Fixed some issues with stateless Lookup Table

It works, but is very slow.

.gitignore

@@ -2,3 +2,4 @@ testing/
 
 .zig-cache/
 zig-out/
+zig-pkg/

.zed/debug.json

@@ -11,7 +11,7 @@
 
 		"build": {
 			"command": "zig",
-			"args": ["build", "-Duse_c_libs=true", "-Ddebug=true"],
+			"args": ["build", "-Ddebug=true"],
 		},
 
 		"program": "zig-out/bin/unsquashfs",

build.zig

@@ -1,54 +1,28 @@
 const std = @import("std");
 
 pub fn build(b: *std.Build) !void {
-    const use_zig_decomp = b.option(bool, "use_zig_decomp", "Use zig standard library for decompression.") orelse false;
+    // const use_zig_decomp = b.option(bool, "use_zig_decomp", "Use zig standard library for decompression.") orelse false;
     // const allow_lzo = b.option(bool, "allow_lzo", "Compile with lzo support") orelse false;
-    const debug = b.option(bool, "debug", "Enable options to make debugging easier.") orelse false;
+    const debug = b.option(bool, "debug", "Enable options to make debugging easier.");
     const version_string_option = b.option([]const u8, "version", "Version of the library/binary");
 
-    const zig_squashfs_options = b.addOptions();
-    zig_squashfs_options.addOption(bool, "use_zig_decomp", use_zig_decomp);
+    // const zig_squashfs_options = b.addOptions();
+    // zig_squashfs_options.addOption(bool, "use_zig_decomp", use_zig_decomp);
     // zig_squashfs_options.addOption(bool, "allow_lzo", allow_lzo);
 
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
-    const mod = b.addModule("zig_squashfs", .{
-        .root_source_file = b.path("src/root.zig"),
-        .target = target,
-        .optimize = if (debug == true) .Debug else optimize,
-        .link_libc = !use_zig_decomp,
-        .valgrind = debug,
-        .error_tracing = debug,
-        .strip = if (debug == true) false else null,
+
+    const lib = b.addLibrary(.{
+        .name = "squashfs",
+        .root_module = b.createModule(.{
+            .optimize = if (debug == true) .Debug else optimize,
+            .target = target,
+            .valgrind = debug,
+            .root_source_file = b.path("src/root.zig"),
+        }),
+        .use_llvm = debug,
     });
-    mod.addOptions("config", zig_squashfs_options);
-    if (!use_zig_decomp) {
-        var zlib_ng = b.dependency("zlib_ng", .{
-            .target = target,
-            .optimize = optimize,
-        });
-        mod.linkLibrary(zlib_ng.artifact("zng"));
-
-        mod.linkSystemLibrary("lzma", .{ .preferred_link_mode = .static });
-
-        var minilzo = b.dependency("minilzo", .{
-            .target = target,
-            .optimize = optimize,
-        });
-        mod.linkLibrary(minilzo.artifact("minilzo"));
-
-        var lz4 = b.dependency("lz4", .{
-            .target = target,
-            .optimize = optimize,
-        });
-        mod.linkLibrary(lz4.artifact("lz4"));
-
-        var zstd = b.dependency("zstd", .{
-            .target = target,
-            .optimize = optimize,
-        });
-        mod.linkLibrary(zstd.artifact("zstd"));
-    }
 
     var version = version_string_option orelse "0.0.0-testing";
     if (version[0] == 'v') version = version[1..];
@@ -58,41 +32,30 @@ pub fn build(b: *std.Build) !void {
         "version",
         try std.SemanticVersion.parse(version),
     );
-
-    var exe_mod = b.createModule(.{
-        .root_source_file = b.path("src/bin/unsquashfs.zig"),
-        .target = target,
-        .optimize = if (debug == true) .Debug else optimize,
-        .link_libc = !use_zig_decomp,
-        .imports = &.{
-            .{ .name = "zig_squashfs", .module = mod },
-        },
-        .valgrind = debug,
-        .error_tracing = debug,
-        .strip = if (debug == true) false else null,
-    });
-    exe_mod.addOptions("config", unsquashfs_options);
     const exe = b.addExecutable(.{
         .name = "unsquashfs",
-        .root_module = exe_mod,
-        .use_llvm = debug,
-    });
-
-    const lib = b.addLibrary(.{
-        .name = "squashfs",
-        .root_module = mod,
+        .root_module = b.createModule(.{
+            .optimize = if (debug == true) .Debug else optimize,
+            .target = target,
+            .valgrind = debug,
+            .root_source_file = b.path("src/bin/unsquashfs.zig"),
+            .imports = &.{
+                .{ .name = "zig_squashfs", .module = lib.root_module },
+            },
+        }),
         .use_llvm = debug,
     });
+    exe.root_module.addOptions("config", unsquashfs_options);
 
     b.installArtifact(lib);
     b.installArtifact(exe);
 
     const mod_tests = b.addTest(.{
-        .root_module = mod,
-        .test_runner = .{
-            .mode = .simple,
-            .path = b.path("src/test.zig"),
-        },
+        .root_module = b.createModule(.{
+            .optimize = optimize,
+            .target = target,
+            .root_source_file = b.path("src/test.zig"),
+        }),
     });
     const run_mod_tests = b.addRunArtifact(mod_tests);
     const test_step = b.step("test", "Run tests");
@@ -101,11 +64,11 @@ pub fn build(b: *std.Build) !void {
     // zls build check steps
     const lib_check = b.addLibrary(.{
         .name = "squashfs",
-        .root_module = mod,
+        .root_module = exe.root_module,
     });
     const exe_check = b.addExecutable(.{
         .name = "unsquashfs",
-        .root_module = exe_mod,
+        .root_module = lib.root_module,
     });
     const check = b.step("check", "Check if unsquashfs compiles");
     check.dependOn(&lib_check.step);

src/archive.zig

@@ -1,121 +1,178 @@
-//! A squashfs archive read from a file.
-//! Can be used to directly access File's contents or extract to the filesystem.
-
 const std = @import("std");
-const File = std.fs.File;
-const builtin = @import("builtin");
+const Io = std.Io;
 
-const config = @import("config");
-
-const cDecomp = @import("decomp/misc_c.zig");
-const Decomp = @import("decomp/zig_decomp.zig");
 const ExtractionOptions = @import("options.zig");
+const File = @import("file.zig");
 const Inode = @import("inode.zig");
-const InodeRef = Inode.Ref;
-const BlockSize = @import("inode_data/file.zig").BlockSize;
-const SfsFile = @import("file.zig");
-const Superblock = @import("super.zig").Superblock;
-const Tables = @import("tables.zig");
+const LookupTable = @import("lookup_table.zig");
+const Decompressor = @import("util/decompressor.zig");
 const MetadataReader = @import("util/metadata.zig");
+const Utils = @import("util/misc.zig");
 const OffsetFile = @import("util/offset_file.zig");
-const XattrTable = @import("xattr.zig");
 
 const Archive = @This();
 
-alloc: std.mem.Allocator,
-
-fil: OffsetFile,
-
+file: OffsetFile,
 super: Superblock,
 
-tables: ?Tables = null,
+stateless_decomp: Decompressor,
 
-decomp: if (config.use_zig_decomp) Decomp.DecompFn else union(enum) {
-    gzip: @import("decomp/gzip.zig"),
-    lzma: @import("decomp/lzma.zig"),
-    lzo: void,
-    xz: @import("decomp/lzma.zig"),
-    lz4: void,
-    zstd: @import("decomp/zstd.zig"),
-
-    pub fn decomp(self: @This(), in: []u8, out: []u8) !usize {
-        return switch (self) {
-            .gzip => |*g| g.decompress(in, out),
-            .zstd => |*z| z.decompress(in, out),
-            .lzma, .xz => |*d| d.decompress(in, out),
-            .lz4 => cDecomp.lz4(in, out),
-            .lzo => cDecomp.lzo(in, out),
-        };
-    }
-},
-
-/// Default settings using std.Thread.getCpuCount() threads and the minimum of 4gb or half of system memory for memory usage.
-pub fn init(alloc: std.mem.Allocator, fil: File, offset: u64) !Archive {
+pub fn init(io: Io, file: std.Io.File, offset: u64) !Archive {
+    var rdr = file.reader(io, &[0]u8{});
+    try rdr.seekTo(offset);
     var super: Superblock = undefined;
-    const red = try fil.pread(@ptrCast(&super), offset);
-    std.debug.assert(red == @sizeOf(Superblock));
-    try super.validate();
-    const off_fil: OffsetFile = .init(fil, offset);
+    try rdr.interface.readSliceEndian(Superblock, @ptrCast(&super), .little);
     return .{
-        .alloc = alloc,
-        .fil = off_fil,
-        .decomp = if (config.use_zig_decomp)
-            switch (super.compression) {
-                .lz4 => return error.Lz4Unsupported,
-                .lzo => return error.LzoUnsupported,
-                .gzip => Decomp.gzip,
-                .lzma => Decomp.lzma,
-                .xz => Decomp.xz,
-                .zstd => Decomp.zstd,
-            }
-        else switch (super.compression) {
-            .gzip => .{ .gzip = .init(alloc) },
-            .zstd => .{ .zstd = .init(alloc) },
-            .xz => .{ .xz = .init(alloc, true) },
-            .lzma => .{ .lzma = .init(alloc, false) },
-            .lzo => .{ .lzo = .{} },
-            .lz4 => .{ .lz4 = .{} },
-        },
+        .file = .init(file, offset),
         .super = super,
+
+        .stateless_decomp = switch (super.compression) {
+            .gzip => @import("decomp/zlib.zig").stateless_decompressor,
+            .lzma => @import("decomp/lzma.zig").stateless_decompressor,
+            .lzo => return error.LzoUnsupported,
+            .xz => @import("decomp/xz.zig").stateless_decompressor,
+            .lz4 => return error.Lz4Unsupported,
+            .zstd => @import("decomp/zstd.zig").stateless_decompressor,
+        },
     };
 }
-pub fn deinit(self: *Archive) void {
-    if (self.tables != null)
-        self.tables.?.deinit();
+
+/// The root folder of the Archive. Used to open other Files.
+pub fn root(self: Archive, alloc: std.mem.Allocator, io: Io) !File {
+    const root_inode = try Utils.inodeFromRef(
+        alloc,
+        io,
+        self.file,
+        &self.stateless_decomp,
+        self.super.inode_start,
+        self.super.block_size,
+        self.super.root_ref,
+    );
+    return .init(alloc, self, root_inode, "");
+}
+/// Opens a File within the archive.
+pub fn open(self: Archive, alloc: std.mem.Allocator, io: Io, filepath: []const u8) !File {
+    const root_file = try self.root(alloc, io);
+    const path = std.mem.trim(u8, filepath, "/");
+    if (Utils.pathIsSelf(path))
+        return root_file;
+    defer root_file.deinit();
+    return root_file.open(alloc, io, filepath);
+}
+/// Extract the entire archive contents to the given directory.
+pub fn extract(self: Archive, alloc: std.mem.Allocator, io: Io, extract_dir: []const u8, options: ExtractionOptions) !void {
+    const root_inode = try Utils.inodeFromRef(
+        alloc,
+        io,
+        self.file,
+        &self.stateless_decomp,
+        self.super.inode_start,
+        self.super.block_size,
+        self.super.root_ref,
+    );
+    return root_inode.extract(alloc, io, self.file, self.super, extract_dir, options);
 }
 
-pub fn inode(self: *Archive, alloc: std.mem.Allocator, num: u32) !Inode {
-    if (self.tables == null)
-        self.tables = try .init(alloc, self);
-    const ref = try self.export_table.get(num - 1);
-    var rdr = try self.fil.readerAt(ref.block_start + self.super.inode_start, &[0]u8{});
-    var meta: MetadataReader = .init(alloc, &rdr.interface, &self.decomp);
-    try meta.interface.discardAll(ref.block_offset);
-    return try .read(alloc, &meta.interface, self.super.block_size);
+/// Returns the inode with the given inode number.
+/// Requires that the archive is exportable (has an export lookup table).
+pub fn inode(self: Archive, alloc: std.mem.Allocator, io: Io, num: u32) !Inode {
+    if (!self.super.flags.exportable)
+        return error.NotExportable;
+    const ref = try LookupTable.lookupValue(
+        Inode.Ref,
+        alloc,
+        io,
+        &self.stateless_decomp,
+        self.file,
+        self.super.export_start,
+        num + 1,
+    );
+    return Utils.inodeFromRef(
+        alloc,
+        io,
+        self.file,
+        &self.stateless_decomp,
+        self.super.inode_start,
+        self.super.block_size,
+        ref,
+    );
+}
+/// Returns a value at the given index from the Archive's id (uid/gid) table.
+pub fn idTable(self: Archive, alloc: std.mem.Allocator, io: Io, idx: u32) !u16 {
+    return LookupTable.lookupValue(
+        u16,
+        alloc,
+        io,
+        &self.stateless_decomp,
+        self.file,
+        self.super.id_start,
+        idx,
+    );
 }
 
-pub fn root(self: *Archive, alloc: std.mem.Allocator) !SfsFile {
-    if (self.tables == null)
-        self.tables = try .init(alloc, self);
-    var rdr = try self.fil.readerAt(self.super.root_ref.block_start + self.super.inode_start, &[0]u8{});
-    var meta: MetadataReader = .init(alloc, &rdr.interface, self.decomp);
-    try meta.interface.discardAll(self.super.root_ref.block_offset);
-    const in: Inode = try .read(alloc, &meta.interface, self.super.block_size);
-    return .init(self, in, "");
-}
+// Superblock
 
-pub fn open(self: *Archive, alloc: std.mem.Allocator, path: []const u8) !SfsFile {
-    if (self.tables == null)
-        self.tables = try .init(alloc, self);
-    var root_fil = try self.root(alloc);
-    defer if (!SfsFile.pathIsSelf(path)) root_fil.deinit();
-    return root_fil.open(path);
-}
+const SQUASHFS_MAGIC: u32 = std.mem.readInt(u32, "hsqs", .little);
 
-pub fn extract(self: Archive, alloc: std.mem.Allocator, path: []const u8, options: ExtractionOptions) !void {
-    var rdr = try self.fil.readerAt(self.super.root_ref.block_start + self.super.inode_start, &[0]u8{});
-    var meta: MetadataReader = .init(self.alloc, &rdr.interface, self.decomp);
-    try meta.interface.discardAll(self.super.root_ref.block_offset);
-    const in: Inode = try .read(self.alloc, &meta.interface, self.super.block_size);
-    try in.extractTo(alloc, self, path, options);
-}
+const SuperblockError = error{
+    InvalidMagic,
+    InvalidBlockLog,
+    InvalidVersion,
+    InvalidCheck,
+};
+
+/// A squashfs Superblock
+pub const Superblock = extern struct {
+    magic: u32,
+    inode_count: u32,
+    mod_time: u32,
+    block_size: u32,
+    frag_count: u32,
+    compression: enum(u16) {
+        gzip = 1,
+        lzma,
+        lzo,
+        xz,
+        lz4,
+        zstd,
+    },
+    block_log: u16,
+    flags: packed struct(u16) {
+        inode_uncompressed: bool,
+        data_uncompressed: bool,
+        check: bool,
+        frag_uncompressed: bool,
+        fragment_never: bool,
+        fragment_always: bool,
+        duplicates: bool,
+        exportable: bool,
+        xattr_uncompressed: bool,
+        xattr_never: bool,
+        compression_options: bool,
+        ids_uncompressed: bool,
+        _: u4,
+    },
+    id_count: u16,
+    ver_maj: u16,
+    ver_min: u16,
+    root_ref: Inode.Ref,
+    size: u64,
+    id_start: u64,
+    xattr_start: u64,
+    inode_start: u64,
+    dir_start: u64,
+    frag_start: u64,
+    export_start: u64,
+
+    /// Validate the Superblock. If an error is returned, it's likely the archive is corrupted or not a squashfs archive.
+    pub fn validate(self: Superblock) !void {
+        if (self.magic != SQUASHFS_MAGIC)
+            return SuperblockError.InvalidMagic;
+        if (self.flags.check)
+            return SuperblockError.InvalidCheck;
+        if (self.ver_maj != 4 or self.ver_min != 0)
+            return SuperblockError.InvalidVersion;
+        if (std.math.log2(self.block_size) != self.block_log)
+            return SuperblockError.InvalidBlockLog;
+    }
+};

src/bin/unsquashfs.zig

@@ -1,5 +1,6 @@
 const std = @import("std");
-const Writer = std.Io.Writer;
+const Io = std.Io;
+const Writer = Io.Writer;
 const builtin = @import("builtin");
 
 const config = @import("config");
@@ -17,7 +18,7 @@ const help_mgs =
     \\  -dx             Don't set xattr values
     \\  -dp             Don't set permissions (includes setting uid & gid owner)
     \\
-    \\  -p <threads>    Specify how many threads to use. If no present or zero, the system's logical cores count is used.
+    \\  -p <threads>    Specify how many threads to use. If not present or zero, the system's logical cores count is used.
     \\  -v              Verbose
     \\
     \\  --force         Force extraction. If the destination already exists, it will be deleted.
@@ -38,21 +39,26 @@ var ignore_xattrs: bool = false;
 var ignore_permissions: bool = false;
 var force: bool = false;
 
-pub fn main() !void {
-    const alloc = std.heap.smp_allocator;
-    var stdout = std.fs.File.stdout();
-    var out = stdout.writer(&[0]u8{});
+pub fn main(init: std.process.Init) !void {
+    const alloc = init.gpa;
+    const io = init.io;
+
+    var stdout = std.Io.File.stdout();
+    defer stdout.close(io);
+    var out = stdout.writer(io, &[0]u8{});
     defer out.interface.flush() catch {};
-    try handleArgs(alloc, &out.interface);
+
+    try handleArgs(init.minimal.args, &out.interface);
     if (archive.len == 0) {
         try out.interface.print("You must provide a squashfs archive\n", .{});
         try out.interface.print(help_mgs, .{});
         return;
     }
-    var fil: std.fs.File = try std.fs.cwd().openFile(archive, .{}); //TODO: Handle error gracefully.
-    defer fil.close();
-    var arc: squashfs.Archive = try .init(alloc, fil, offset); //TODO: Update when memory size matters. //TODO: Handle error gracefully.
-    defer arc.deinit();
+
+    var fil = try Io.Dir.cwd().openFile(io, archive, .{}); //TODO: Handle error gracefully.
+    defer fil.close(io);
+
+    var arc: squashfs.Archive = try .init(io, fil, offset); //TODO: Handle error gracefully.
     const options: squashfs.ExtractionOptions = .{
         .threads = if (threads == 0) try std.Thread.getCpuCount() else threads,
         .verbose = verbose,
@@ -60,18 +66,19 @@ pub fn main() !void {
         .ignore_xattr = ignore_xattrs,
         .ignore_permissions = ignore_permissions,
     };
+
     if (force)
-        try std.fs.cwd().deleteTree(extLoc);
-    try arc.extract(alloc, extLoc, options); //TODO: Handle error gracefully.
+        try Io.Dir.cwd().deleteTree(io, extLoc);
+    try arc.extract(alloc, io, extLoc, options); //TODO: Handle error gracefully.
 }
 
-fn handleArgs(alloc: std.mem.Allocator, out: *Writer) !void {
-    var args = try std.process.argsWithAllocator(alloc);
-    defer args.deinit();
-    _ = args.next(); // args[0] is the application launch command.
-    while (args.next()) |arg| {
+fn handleArgs(args: std.process.Args, out: *Writer) !void {
+    var arg_iter = args.iterate();
+    defer arg_iter.deinit();
+    _ = arg_iter.next(); // args[0] is the application launch command.
+    while (arg_iter.next()) |arg| {
         if (std.mem.eql(u8, arg, "-o")) {
-            const nxt = args.next();
+            const nxt = arg_iter.next();
             if (nxt == null or nxt.?.len == 0) {
                 try out.print("-o must be followed by a number\n", .{});
                 return errors.InvalidArguments;
@@ -82,7 +89,7 @@ fn handleArgs(alloc: std.mem.Allocator, out: *Writer) !void {
             };
             continue;
         } else if (std.mem.eql(u8, arg, "-d")) {
-            const nxt = args.next();
+            const nxt = arg_iter.next();
             if (nxt == null or nxt.?.len == 0) {
                 try out.print("-d must be followed by a location\n", .{});
                 return errors.InvalidArguments;
@@ -90,7 +97,7 @@ fn handleArgs(alloc: std.mem.Allocator, out: *Writer) !void {
             extLoc = nxt.?;
             continue;
         } else if (std.mem.eql(u8, arg, "-p")) {
-            const nxt = args.next();
+            const nxt = arg_iter.next();
             if (nxt == null or nxt.?.len == 0) {
                 try out.print("-p must be followed by a number\n", .{});
                 return errors.InvalidArguments;

src/decomp.zig

@@ -1,25 +1,32 @@
 const std = @import("std");
 
-const Decompressor = @This();
+const Decompressor = @import("util/decompressor.zig");
 
-pub const Error = error{
-    OutOfMemory,
-    BadInput,
-    OutputTooSmall,
-    ReadFailed,
-    WriteFailed,
-    EndOfStream,
+pub const Decomp = union(enum) {
+    gzip: @import("decomp/zlib.zig"),
+    lzma: @import("decomp/lzma.zig"),
+    lzo: void,
+    xz: @import("decomp/xz.zig"),
+    lz4: void,
+    zstd: @import("decomp/zstd.zig"),
+
+    pub fn deinit(self: *Decomp) void {
+        switch (self.*) {
+            .gzip => self.gzip.deinit(),
+            .lzma => self.lzma.deinit(),
+            .xz => self.xz.deinit(),
+            .zstd => self.zstd.deinit(),
+            else => unreachable,
+        }
+    }
+
+    pub fn decompressor(self: *Decomp) *Decompressor {
+        return switch (self.*) {
+            .gzip => &self.gzip.interface,
+            .lzma => &self.lzma.interface,
+            .xz => &self.xz.interface,
+            .zstd => &self.zstd.interface,
+            else => unreachable,
+        };
+    }
 };
-
-vtable: *const struct {
-    decompress: *const fn (*Decompressor, []u8, []u8) Error!usize = DefaultDecompress,
-    stateless: *const fn (std.mem.Allocator, []u8, []u8) Error!usize,
-},
-
-pub fn decompress(self: *Decompressor, in: []u8, out: []u8) Error!usize {
-    return self.vtable.decompress(self, in, out);
-}
-
-fn DefaultDecompress(self: *Decompressor, in: []u8, out: []u8) Error!usize {
-    return self.vtable.stateless(std.heap.smp_allocator, in, out);
-}

src/decomp/c.zig

@@ -1,14 +0,0 @@
-const std = @import("std");
-const Reader = std.Io.Reader;
-const builtin = @import("builtin");
-
-const config = @import("config");
-
-pub const c = @cImport({
-    @cInclude("zlib-ng.h");
-    @cInclude("lzma.h");
-    @cInclude("lz4.h");
-    @cInclude("zstd.h");
-    @cInclude("zstd_errors.h");
-    @cInclude("lzo/minilzo.h");
-});

src/decomp/gzip.zig

@@ -1,114 +0,0 @@
-const std = @import("std");
-const Reader = std.Io.Reader;
-const builtin = @import("builtin");
-
-const Decompressor = @import("../decomp.zig");
-const c = @import("c.zig").c;
-const zng_stream = c.zng_stream;
-
-const ZlibErrors = error{
-    OutOfMemory,
-    OutputBufferTooSmall,
-    BadData,
-    StreamError,
-    Unknown,
-};
-
-const Self = @This();
-
-alloc: std.mem.Allocator,
-
-streams: std.AutoHashMap(std.Thread.Id, zng_stream),
-interface: Decompressor = .{ .vtable = &.{
-    .decompress = decompress,
-    .stateless = stateless,
-} },
-
-err: ?ZlibErrors = null,
-
-pub fn init(alloc: std.mem.Allocator) !Self {
-    return .{
-        .alloc = alloc,
-        .streams = .init(alloc),
-    };
-}
-pub fn deinit(self: Self) void {
-    var iter = self.streams.keyIterator();
-    while (iter.next()) |key| {
-        _ = c.inflateEnd(self.streams.getPtr(key).?);
-    }
-    self.streams.deinit(self.alloc);
-}
-
-fn decompress(decomp: *Decompressor, in: []u8, out: []u8) Decompressor.Error!usize {
-    var self: *Self = @fieldParentPtr("interface", decomp);
-
-    var stream = try self.getOrCreate();
-    stream.next_in = in.ptr;
-    stream.avail_in = @truncate(in.len);
-    stream.next_out = out.ptr;
-    stream.avail_out = @truncate(out.len);
-    var res = c.zng_inflateReset(stream);
-    switch (res) {
-        c.Z_OK => {},
-        c.Z_STREAM_ERROR => {
-            self.err = ZlibErrors.StreamError;
-            return Decompressor.Error.BadInput;
-        },
-        else => {
-            self.err = ZlibErrors.Unknown;
-            return Decompressor.Error.BadInput;
-        },
-    }
-    res = c.zng_inflate(stream, c.Z_FINISH);
-    switch (res) {
-        c.Z_OK => return stream.total_out,
-        c.Z_MEM_ERROR => {
-            self.err = ZlibErrors.OutOfMemory;
-            return Decompressor.Error.OutOfMemory;
-        },
-        c.Z_BUF_ERROR => {
-            self.err = ZlibErrors.OutputBufferTooSmall;
-            return Decompressor.Error.OutputTooSmall;
-        },
-        c.Z_DATA_ERROR => {
-            self.err = ZlibErrors.BadData;
-            return Decompressor.Error.BadInput;
-        },
-        else => {
-            self.err = ZlibErrors.Unknown;
-            return Decompressor.Error.BadInput;
-        },
-    }
-}
-inline fn getOrCreate(self: *Self) Decompressor.Error!*zng_stream {
-    const res = try self.streams.getOrPut(std.Thread.getCurrentId());
-    if (res.found_existing) return res.value_ptr;
-    res.value_ptr.* = .{
-        .zalloc = zalloc,
-        .zfree = zfree,
-        .@"opaque" = @ptrCast(self),
-    };
-    return res.value_ptr;
-}
-
-fn zalloc(self_ptr: ?*anyopaque, items: c_uint, size: c_uint) callconv(.c) ?*anyopaque {
-    var self: *Self = @ptrCast(@alignCast(self_ptr));
-    return self.alloc.rawAlloc(items * size, .@"1", 0);
-}
-fn zfree(self_ptr: ?*anyopaque, alloc_ptr: ?*anyopaque) callconv(.c) void {
-    var self: *Self = @ptrCast(@alignCast(self_ptr));
-    self.alloc.rawFree(@ptrCast(alloc_ptr), .@"1", 0);
-}
-
-fn stateless(_: std.mem.Allocator, in: []u8, out: []u8) Decompressor.Error!usize {
-    var out_len = out.len;
-    const res = c.zng_uncompress(out.ptr, &out_len, in.ptr, in.len);
-    return switch (res) {
-        c.Z_OK => out_len,
-        c.Z_MEM_ERROR => Decompressor.Error.OutOfMemory,
-        c.Z_BUF_ERROR => Decompressor.Error.OutputTooSmall,
-        c.Z_DATA_ERROR => Decompressor.Error.BadInput,
-        else => Decompressor.Error.BadInput,
-    };
-}

src/decomp/lzma.zig

@@ -1,146 +1,86 @@
 const std = @import("std");
-const builtin = @import("builtin");
+const Reader = std.Io.Reader;
+const lzma = std.compress.lzma;
+const Node = std.SinglyLinkedList.Node;
 
-const Decompressor = @import("../decomp.zig");
-const c = @import("c.zig").c;
-const stream = c.lzma_stream;
+const Decompressor = @import("../util/decompressor.zig");
+const Error = Decompressor.Error;
 
 const Self = @This();
 
+const Buffer = struct {
+    node: Node,
+    buf: []u8,
+};
+
+interface: Decompressor = .{ .decomp_fn = decomp },
+
 alloc: std.mem.Allocator,
-streams: std.AutoHashMap(std.Thread.Id, stream),
 
-xz: bool,
-interface: Decompressor = .{ .vtable = &.{
-    .decompress = decompress,
-    .stateless = stateless,
-} },
+block_size: u32,
+buffers: std.ArrayList(Buffer),
+buffer_queue: std.SinglyLinkedList = .{},
 
-err: ?LzmaError = null,
-
-pub fn init(alloc: std.mem.Allocator, xz: bool) !Self {
+pub fn init(alloc: std.mem.Allocator, block_size: u32) !Self {
     return .{
         .alloc = alloc,
-        .streams = .init(alloc),
-        .xz = xz,
+
+        .block_size = block_size,
+        .buffers = try .initCapacity(alloc, 5),
     };
 }
-pub fn deinit(self: Self) void {
-    var iter = self.streams.keyIterator();
-    while (iter.next()) |key|
-        c.lzma_end(self.streams.getPtr(key));
-    self.streams.deinit();
+pub fn deinit(self: *Self) void {
+    for (self.buffers.items) |buf|
+        self.alloc.free(buf.buf);
+    self.buffers.deinit(self.alloc);
 }
 
-pub fn decompress(decomp: *Decompressor, in: []u8, out: []u8) Decompressor.Error!usize {
-    var self: *Self = @fieldParentPtr("interface", decomp);
-
-    var strm = try self.getOrCreate();
-    strm.next_in = in.ptr;
-    strm.avail_in = in.len;
-    strm.next_out = out.ptr;
-    strm.avail_out = out.len;
-
-    var res = if (self.xz)
-        c.lzma_stream_decoder(strm, in.len * 2, 0)
-    else
-        c.lzma_alone_decoder(strm, in.len * 2);
-    switch (res) {
-        c.LZMA_OK => {},
-        c.LZMA_MEM_ERROR => {
-            self.err = LzmaError.LzmaMemoryError;
-            return Decompressor.Error.OutOfMemory;
-        },
-        c.LZMA_PROG_ERROR => {
-            self.err = LzmaError.LzmaProgramError;
-            return Decompressor.Error.BadInput;
-        },
-        else => {
-            self.err = LzmaError.Unknown;
-            return Decompressor.Error.BadInput;
-        },
+fn decomp(d: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    if (d == null) {
+        var buf = try alloc.alloc(u8, in.len * 2);
+        defer alloc.free(buf);
+        return lzmaDecomp(alloc, &buf, in, out) catch |err| return switch (err) {
+            error.OutOfMemory => Error.OutOfMemory,
+            else => Error.ReadFailed,
+        };
     }
-    while (res == c.LZMA_OK)
-        res = c.lzma_code(strm, c.LZMA_RUN);
-    switch (res) {
-        c.LZMA_STREAM_END => return strm.total_out,
-        c.LZMA_MEM_ERROR => {
-            self.err = LzmaError.LzmaMemoryError;
-            return Decompressor.Error.OutOfMemory;
-        },
-        c.LZMA_MEMLIMIT_ERROR => {
-            self.err = LzmaError.LzmaMemoryLimit;
-            return Decompressor.Error.OutOfMemory;
-        },
-        c.LZMA_FORMAT_ERROR => {
-            self.err = LzmaError.LzmaBadFormat;
-            return Decompressor.Error.BadInput;
-        },
-        c.LZMA_DATA_ERROR => {
-            self.err = LzmaError.LzmaDataCorrupt;
-            return Decompressor.Error.BadInput;
-        },
-        c.LZMA_BUF_ERROR => {
-            self.err = LzmaError.LzmaCannotProgress;
-            return Decompressor.Error.BadInput;
-        },
-        c.LZMA_PROG_ERROR => {
-            self.err = LzmaError.LzmaProgramError;
-            return Decompressor.Error.BadInput;
-        },
-        else => {
-            self.err = LzmaError.Unknown;
-            return Decompressor.Error.BadInput;
-        },
+    var self: *Self = @fieldParentPtr("interface", @constCast(d.?));
+    const buf_node = self.buffer_queue.popFirst();
+    var buf: *Buffer = undefined;
+    if (buf_node == null) {
+        const new_buf = try self.buffers.addOne(self.alloc);
+        new_buf.* = .{ .node = .{}, .buf = try self.alloc.alloc(u8, self.block_size) };
+        buf = new_buf;
+    } else {
+        buf = @fieldParentPtr("node", buf_node.?);
     }
-}
-pub fn stateless(_: std.mem.Allocator, in: []u8, out: []u8) Decompressor.Error!usize {
-    var strm = c.lzma_stream{
-        .next_in = in.ptr,
-        .avail_in = in.len,
-        .next_out = out.ptr,
-        .avail_out = out.len,
-    };
-
-    var res = c.lzma_auto_decoder(&strm, out.len * 2, 0);
-    switch (res) {
-        c.LZMA_OK => {},
-        c.LZMA_MEM_ERROR => return Decompressor.Error.OutOfMemory,
-        c.LZMA_PROG_ERROR => return Decompressor.Error.BadInput,
-        else => return Decompressor.Error.BadInput,
-    }
-    while (res == c.LZMA_OK)
-        res = c.lzma_code(&strm, c.LZMA_RUN);
-    return switch (res) {
-        c.LZMA_STREAM_END => strm.total_out,
-        c.LZMA_MEM_ERROR => Decompressor.Error.OutOfMemory,
-        c.LZMA_MEMLIMIT_ERROR => Decompressor.Error.OutOfMemory,
-        c.LZMA_FORMAT_ERROR => Decompressor.Error.BadInput,
-        c.LZMA_DATA_ERROR => Decompressor.Error.BadInput,
-        c.LZMA_BUF_ERROR => Decompressor.Error.BadInput,
-        c.LZMA_PROG_ERROR => Decompressor.Error.BadInput,
-        else => Decompressor.Error.BadInput,
+    defer self.buffer_queue.prepend(&buf.node);
+    return lzmaDecomp(self.alloc, &buf.buf, in, out) catch |err| {
+        // self.err = err;
+        return switch (err) {
+            error.OutOfMemory => Error.OutOfMemory,
+            else => Error.ReadFailed,
+        };
     };
 }
 
-inline fn getOrCreate(self: *Self) Decompressor.Error!*stream {
-    const res = try self.streams.getOrPut(std.Thread.getCurrentId());
-    if (res.found_existing) return res.value_ptr;
+inline fn lzmaDecomp(alloc: std.mem.Allocator, buffer: *[]u8, in: []u8, out: []u8) !usize {
+    var rdr: Reader = .fixed(in);
+    var d = try lzma.Decompress.initOptions(&rdr, alloc, buffer.*, .{ .allow_incomplete = true }, 3 * 1024 * 1024);
+    defer {
+        buffer.* = d.takeBuffer();
+        d.deinit();
+    }
 
-    // Ideally, the zero value should be LZMA_STREAM_INIT, but translate-c can't handle it properly.
-    // According to lzma, setting it to entirely zero values *should* work.
-    // res.value_ptr.* = c.LZMA_STREAM_INIT;
-    res.value_ptr.* = std.mem.zeroInit(stream, .{});
-    return res.value_ptr;
+    return d.reader.readSliceShort(out);
 }
 
-pub const LzmaError = error{
-    OutOfMemory,
-    LzmaMemoryError,
-    LzmaMemoryLimit,
-    LzmaBadFormat,
-    LzmaDataCorrupt,
-    LzmaCannotProgress,
-    LzmaProgramError,
-    Unknown,
-};
+// Stateless
+
+pub const stateless_decompressor: Decompressor = .{ .decomp_fn = statelessDecomp };
+
+fn statelessDecomp(_: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var buf = try alloc.alloc(u8, in.len);
+    defer alloc.free(buf);
+    return lzmaDecomp(alloc, &buf, in, out) catch return Error.ReadFailed;
+}

src/decomp/misc_c.zig

@@ -1,43 +0,0 @@
-const std = @import("std");
-
-const Decompressor = @import("../decomp.zig");
-const c = @import("c.zig").c;
-
-pub const Lzo = struct {
-    interface: Decompressor = .{ .vtable = &.{ .stateless = lzo } },
-};
-
-fn lzo(_: std.mem.Allocator, in: []u8, out: []u8) Decompressor.Error!usize {
-    var res = c.lzo_init();
-    if (res != 0) return Decompressor.Error.BadInput;
-    var out_len: usize = out.len;
-    res = c.lzo1x_decompress(in.ptr, in.len, out.ptr, &out_len, null);
-
-    return switch (res) {
-        c.LZO_E_OK => out_len,
-        c.LZO_E_OUT_OF_MEMORY => Decompressor.Error.OutOfMemory,
-        c.LZO_E_ERROR,
-        c.LZO_E_INPUT_OVERRUN,
-        c.LZO_E_LOOKBEHIND_OVERRUN,
-        c.LZO_E_EOF_NOT_FOUND,
-        c.LZO_E_NOT_YET_IMPLEMENTED,
-        c.LZO_E_INVALID_ARGUMENT,
-        c.LZO_E_INVALID_ALIGNMENT,
-        => Decompressor.Error.BadInput,
-        c.LZO_E_INPUT_NOT_CONSUMED,
-        c.LZO_E_OUTPUT_NOT_CONSUMED,
-        c.LZO_E_OUTPUT_OVERRUN,
-        => Decompressor.Error.OutputTooSmall,
-        else => Decompressor.Error.BadInput,
-    };
-}
-
-pub const Lz4 = struct {
-    interface: Decompressor = .{ .vtable = &.{ .stateless = lz4 } },
-};
-
-fn lz4(_: std.mem.Allocator, in: []u8, out: []u8) Decompressor.Error!usize {
-    const res = c.LZ4_decompress_safe(in.ptr, out.ptr, @intCast(in.len), @intCast(out.len));
-    if (res > 0) return @abs(res);
-    return Decompressor.Error.BadInput; // TODO: Find out what error values it can return.
-}

src/decomp/xz.zig

@@ -0,0 +1,80 @@
+const std = @import("std");
+const Reader = std.Io.Reader;
+const xz = std.compress.xz;
+const Node = std.SinglyLinkedList.Node;
+
+const Decompressor = @import("../util/decompressor.zig");
+const Error = Decompressor.Error;
+
+const Self = @This();
+
+const Buffer = struct {
+    node: Node,
+    buf: []u8,
+};
+
+interface: Decompressor = .{ .decomp_fn = decomp },
+
+alloc: std.mem.Allocator,
+
+block_size: u32,
+buffers: std.ArrayList(Buffer),
+buffer_queue: std.SinglyLinkedList = .{},
+
+pub fn init(alloc: std.mem.Allocator, block_size: u32) !Self {
+    return .{
+        .alloc = alloc,
+
+        .block_size = block_size,
+        .buffers = try .initCapacity(alloc, 5),
+    };
+}
+pub fn deinit(self: *Self) void {
+    for (self.buffers.items) |buf|
+        self.alloc.free(buf.buf);
+    self.buffers.deinit(self.alloc);
+}
+
+fn decomp(d: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    if (d == null) {
+        var buf = try alloc.alloc(u8, in.len * 2);
+        defer alloc.free(buf);
+        return xzDecomp(alloc, &buf, in, out) catch return Error.ReadFailed;
+    }
+    var self: *Self = @fieldParentPtr("interface", @constCast(d.?));
+    const buf_node = self.buffer_queue.popFirst();
+    var buf: *Buffer = undefined;
+    if (buf_node == null) {
+        const new_buf = try self.buffers.addOne(self.alloc);
+        new_buf.* = .{ .node = .{}, .buf = try self.alloc.alloc(u8, self.block_size) };
+        buf = new_buf;
+    } else {
+        buf = @fieldParentPtr("node", buf_node.?);
+    }
+    defer self.buffer_queue.prepend(&buf.node);
+    return xzDecomp(self.alloc, &buf.buf, in, out) catch {
+        // self.err = err;
+        return Error.ReadFailed;
+    };
+}
+
+inline fn xzDecomp(alloc: std.mem.Allocator, buffer: *[]u8, in: []u8, out: []u8) !usize {
+    var rdr: Reader = .fixed(in);
+    var d = try xz.Decompress.init(&rdr, alloc, buffer.*);
+    defer {
+        buffer.* = d.takeBuffer();
+        d.deinit();
+    }
+
+    return d.reader.readSliceShort(out);
+}
+
+// Stateless
+
+pub const stateless_decompressor: Decompressor = .{ .decomp_fn = statelessDecomp };
+
+fn statelessDecomp(_: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var buf = try alloc.alloc(u8, in.len);
+    defer alloc.free(buf);
+    return xzDecomp(alloc, &buf, in, out) catch return Error.ReadFailed;
+}

src/decomp/zig_decomp.zig

@@ -1,51 +0,0 @@
-const std = @import("std");
-const Reader = std.Io.Reader;
-const builtin = @import("builtin");
-
-const Decompressor = @import("../decomp.zig");
-
-pub const Gzip = struct {
-    interface: Decompressor = .{ .vtable = &.{ .stateless = gzip } },
-};
-
-pub fn gzip(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    var rdr: Reader = .fixed(in);
-    const buf = try alloc.alloc(u8, out.len);
-    defer alloc.free(buf);
-    var decomp = std.compress.flate.Decompress.init(&rdr, .zlib, buf);
-    return decomp.reader.readSliceShort(out);
-}
-
-pub const Lzma = struct {
-    interface: Decompressor = .{ .vtable = &.{ .stateless = lzma } },
-};
-
-pub fn lzma(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    var rdr: Reader = .fixed(in);
-    var decomp = try std.compress.lzma.decompress(alloc, rdr.adaptToOldInterface());
-    return decomp.read(out);
-}
-
-pub const Xz = struct {
-    interface: Decompressor = .{ .vtable = &.{ .stateless = xz } },
-};
-
-pub fn xz(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    var rdr: Reader = .fixed(in);
-    var decomp = try std.compress.xz.decompress(alloc, rdr.adaptToOldInterface());
-    return decomp.read(out);
-}
-
-pub const Zstd = struct {
-    interface: Decompressor = .{ .vtable = &.{ .stateless = zstd } },
-};
-
-pub fn zstd(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    var rdr: Reader = .fixed(in);
-    const buf = try alloc.alloc(u8, 1024 * 1024);
-    defer alloc.free(buf);
-    var decomp = std.compress.zstd.Decompress.init(&rdr, buf, .{});
-    return decomp.reader.readSliceShort(out) catch |err| {
-        return decomp.err orelse err;
-    };
-}

src/decomp/zlib.zig

@@ -0,0 +1,73 @@
+const std = @import("std");
+const Reader = std.Io.Reader;
+const flate = std.compress.flate;
+const Node = std.SinglyLinkedList.Node;
+
+const Decompressor = @import("../util/decompressor.zig");
+const Error = Decompressor.Error;
+
+const Self = @This();
+
+const Buffer = struct {
+    node: Node,
+    buf: []u8,
+};
+
+interface: Decompressor = .{ .decomp_fn = decomp },
+
+alloc: std.mem.Allocator,
+
+block_size: u32,
+buffers: std.ArrayList(Buffer),
+buffer_queue: std.SinglyLinkedList = .{},
+
+pub fn init(alloc: std.mem.Allocator, block_size: u32) !Self {
+    return .{
+        .alloc = alloc,
+
+        .block_size = block_size,
+        .buffers = try .initCapacity(alloc, 5),
+    };
+}
+pub fn deinit(self: *Self) void {
+    for (self.buffers.items) |buf|
+        self.alloc.free(buf.buf);
+    self.buffers.deinit(self.alloc);
+}
+
+fn decomp(d: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    if (d == null) {
+        const buf = try alloc.alloc(u8, in.len * 2);
+        defer alloc.free(buf);
+        return zlibDecomp(buf, in, out);
+    }
+    var self: *Self = @fieldParentPtr("interface", @constCast(d.?));
+    const buf_node = self.buffer_queue.popFirst();
+    var buf: *Buffer = undefined;
+    if (buf_node == null) {
+        const new_buf = try self.buffers.addOne(self.alloc);
+        new_buf.* = .{ .node = .{}, .buf = try self.alloc.alloc(u8, self.block_size) };
+        buf = new_buf;
+    } else {
+        buf = @fieldParentPtr("node", buf_node.?);
+    }
+    defer self.buffer_queue.prepend(&buf.node);
+    return zlibDecomp(buf.buf, in, out);
+}
+
+inline fn zlibDecomp(buffer: []u8, in: []u8, out: []u8) !usize {
+    var rdr: Reader = .fixed(in);
+    var d = flate.Decompress.init(&rdr, .zlib, buffer);
+
+    return d.reader.readSliceShort(out);
+}
+
+// Stateless
+
+pub const stateless_decompressor: Decompressor = .{ .decomp_fn = statelessDecomp };
+
+fn statelessDecomp(_: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    const buf = try alloc.alloc(u8, in.len * 2);
+    defer alloc.free(buf);
+    return zlibDecomp(buf, in, out);
+}

src/decomp/zstd.zig

@@ -1,216 +1,74 @@
 const std = @import("std");
-const builtin = @import("builtin");
+const Io = std.Io;
+const Reader = std.Io.Reader;
+const zstd = std.compress.zstd;
+const Node = std.SinglyLinkedList.Node;
 
-const Decompressor = @import("../decomp.zig");
-const c = @import("c.zig").c;
-const DCtx = c.ZSTD_DCtx;
+const Decompressor = @import("../util/decompressor.zig");
+const Error = Decompressor.Error;
+
+const Queue = std.Io.Queue([]u8);
 
 const Self = @This();
 
+interface: Decompressor = .{ .decomp_fn = decomp },
+
 alloc: std.mem.Allocator,
-ctx: std.AutoHashMap(std.Thread.Id, *DCtx),
+io: Io,
 
-interface: Decompressor = .{ .vtable = &.{
-    .decompress = decompress,
-    .stateless = stateless,
-} },
-err: ?ZstdError = null,
+block_size: u32,
+buf: [][]u8,
+buf_queue: Queue,
+
+pub fn init(alloc: std.mem.Allocator, io: Io, block_size: u32) !Self {
+    const buf = try alloc.alloc([]u8, 20); // TODO: Choose a better number instead of a random one.
+    var queue: Queue = .init(buf);
+    for (0..20) |_|
+        try queue.putOne(io, try alloc.alloc(u8, block_size + zstd.block_size_max));
 
-pub fn init(alloc: std.mem.Allocator) !Self {
     return .{
         .alloc = alloc,
-        .ctx = .init(alloc),
+        .io = io,
+
+        .block_size = block_size,
+        .buf = buf,
+        .buf_queue = queue,
     };
 }
-pub fn deinit(self: Self) void {
-    var iter = self.ctx.keyIterator();
-    while (iter.next()) |key| {
-        _ = c.ZSTD_freeDCtx(self.ctx.getPtr(key));
+pub fn deinit(self: *Self) void {
+    self.buf_queue.close(self.io);
+    for (self.buf) |buf|
+        self.alloc.free(buf);
+    self.alloc.free(self.buf);
+}
+
+fn decomp(d: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    if (d == null) {
+        const buf = try alloc.alloc(u8, in.len * 2);
+        defer alloc.free(buf);
+        return zstdDecomp(buf, in, out);
     }
-    self.ctx.deinit(self.alloc);
+    var self: *Self = @fieldParentPtr("interface", @constCast(d.?));
+
+    const buf = self.buf_queue.getOne(self.io) catch return Error.ReadFailed;
+    defer self.buf_queue.putOne(self.io, buf) catch {};
+
+    return zstdDecomp(buf, in, out);
 }
 
-pub fn decompress(decomp: *Decompressor, in: []u8, out: []u8) Decompressor.Error!usize {
-    var self: *Self = @fieldParentPtr("interface", decomp);
+inline fn zstdDecomp(buffer: []u8, in: []u8, out: []u8) !usize {
+    var rdr: Reader = .fixed(in);
+    var d = zstd.Decompress.init(&rdr, buffer, .{ .window_len = @truncate(out.len) });
 
-    const ctx = try self.getOrCreate();
-    const res = c.ZSTD_decompressDCtx(ctx, out.ptr, out.len, in.ptr, in.len);
-    try self.checkError(res);
-    return res;
-}
-inline fn getOrCreate(self: *Self) Decompressor.Error!*DCtx {
-    const res = try self.ctx.getOrPut(std.Thread.getCurrentId());
-    if (res.found_existing) {
-        try self.checkError(c.ZSTD_DCtx_reset(res.value_ptr.*, c.ZSTD_reset_session_only));
-        return res.value_ptr.*;
-    }
-    res.value_ptr.* = c.ZSTD_createDCtx() orelse return Decompressor.Error.OutOfMemory;
-    return res.value_ptr.*;
+    return d.reader.readSliceShort(out);
 }
 
-fn stateless(_: std.mem.Allocator, in: []u8, out: []u8) Decompressor.Error!usize {
-    const res = c.ZSTD_decompress(out.ptr, out.len, in.ptr, in.len);
-    if (c.ZSTD_isError(res) == 0) return res;
-    return switch (c.ZSTD_getErrorCode(res)) {
-        c.ZSTD_error_memory_allocation => Decompressor.Error.OutOfMemory,
-        c.ZSTD_error_workSpace_tooSmall,
-        c.ZSTD_error_dstSize_tooSmall,
-        c.ZSTD_error_dstBuffer_null,
-        c.ZSTD_error_noForwardProgress_destFull,
-        => Decompressor.Error.OutputTooSmall,
-        else => Decompressor.Error.BadInput,
-    };
-}
+// Stateless
 
-inline fn checkError(self: *Self, res: usize) Decompressor.Error!void {
-    if (res == 0) return;
-    if (c.ZSTD_isError(res) == 0) return;
-    switch (c.ZSTD_getErrorCode(res)) {
-        c.ZSTD_error_prefix_unknown => {
-            self.err = ZstdError.PrefixUnknown;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_version_unsupported => {
-            self.err = ZstdError.VersionUnsupported;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_frameParameter_unsupported => {
-            self.err = ZstdError.FrameParameterUnsupported;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_frameParameter_windowTooLarge => {
-            self.err = ZstdError.FrameParameterWindowTooLarge;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_corruption_detected => {
-            self.err = ZstdError.CorruptionDetected;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_checksum_wrong => {
-            self.err = ZstdError.ChecksumWrong;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_literals_headerWrong => {
-            self.err = ZstdError.LiteralsHeaderWrong;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_dictionary_corrupted => {
-            self.err = ZstdError.DictionaryCorrupted;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_dictionary_wrong => {
-            self.err = ZstdError.DictionaryWrong;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_dictionaryCreation_failed => {
-            self.err = ZstdError.DictionaryCreationFailed;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_parameter_unsupported => {
-            self.err = ZstdError.ParameterUnsupported;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_parameter_combination_unsupported => {
-            self.err = ZstdError.ParameterCombinationUnsupported;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_parameter_outOfBound => {
-            self.err = ZstdError.ParameterOutOfBound;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_tableLog_tooLarge => {
-            self.err = ZstdError.TableLogTooLarge;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_maxSymbolValue_tooLarge => {
-            self.err = ZstdError.MaxSymbolValueTooLarge;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_maxSymbolValue_tooSmall => {
-            self.err = ZstdError.MaxSymbolValueTooSmall;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_stabilityCondition_notRespected => {
-            self.err = ZstdError.StabilityConditionNotRespected;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_stage_wrong => {
-            self.err = ZstdError.StageWrong;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_init_missing => {
-            self.err = ZstdError.InitMissing;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_memory_allocation => {
-            self.err = ZstdError.MemoryAllocation;
-            return Decompressor.Error.OutOfMemory;
-        },
-        c.ZSTD_error_workSpace_tooSmall => {
-            self.err = ZstdError.WorkSpaceTooSmall;
-            return Decompressor.Error.OutputTooSmall;
-        },
-        c.ZSTD_error_dstSize_tooSmall => {
-            self.err = ZstdError.DstSizeTooSmall;
-            return Decompressor.Error.OutputTooSmall;
-        },
-        c.ZSTD_error_srcSize_wrong => {
-            self.err = ZstdError.SrcSizeWrong;
-            return Decompressor.Error.BadInput;
-        },
-        c.ZSTD_error_dstBuffer_null => {
-            self.err = ZstdError.DstBufferNull;
-            return Decompressor.Error.OutputTooSmall;
-        },
-        c.ZSTD_error_noForwardProgress_destFull => {
-            self.err = ZstdError.NoForwardProgressDestFull;
-            return Decompressor.Error.OutputTooSmall;
-        },
-        c.ZSTD_error_noForwardProgress_inputEmpty => {
-            self.err = ZstdError.NoForwardProgressInputEmpty;
-            return Decompressor.Error.BadInput;
-        },
-        else => {
-            self.err = ZstdError.Generic;
-            return Decompressor.Error.BadInput;
-        },
-    }
+pub const stateless_decompressor: Decompressor = .{ .decomp_fn = statelessDecomp };
+
+fn statelessDecomp(_: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    const buf = try alloc.alloc(u8, out.len + zstd.block_size_max);
+    defer alloc.free(buf);
+    return zstdDecomp(buf, in, out);
 }
-pub const ZstdError = error{
-    OutOfMemory,
-    Generic,
-    PrefixUnknown,
-    VersionUnsupported,
-    FrameParameterUnsupported,
-    FrameParameterWindowTooLarge,
-    CorruptionDetected,
-    ChecksumWrong,
-    LiteralsHeaderWrong,
-    DictionaryCorrupted,
-    DictionaryWrong,
-    DictionaryCreationFailed,
-    ParameterUnsupported,
-    ParameterCombinationUnsupported,
-    ParameterOutOfBound,
-    TableLogTooLarge,
-    MaxSymbolValueTooLarge,
-    MaxSymbolValueTooSmall,
-    CannotProduceUncompressedBlock,
-    StabilityConditionNotRespected,
-    StageWrong,
-    InitMissing,
-    MemoryAllocation,
-    WorkSpaceTooSmall,
-    DstSizeTooSmall,
-    SrcSizeWrong,
-    DstBufferNull,
-    NoForwardProgressDestFull,
-    NoForwardProgressInputEmpty,
-    FrameIndexTooLarge,
-    SeekableIo,
-    DstBufferWrong,
-    SrcBufferWrong,
-    SequenceProducerFailed,
-    ExternalSequencesInvalid,
-    MaxCode,
-};

src/dir_entry.zig

@@ -1,60 +0,0 @@
-//! Directory entry from the directory table.
-
-const std = @import("std");
-const Reader = std.Io.Reader;
-
-const InodeType = @import("inode.zig").InodeType;
-
-const Entry = @This();
-
-const Header = extern struct { // use extern due to bad alignment with packed.
-    count: u32,
-    block_start: u32,
-    num: u32,
-};
-
-const RawEntry = packed struct {
-    offset: u16,
-    inode_offset: i16,
-    inode_type: InodeType,
-    name_size: u16,
-};
-
-block_start: u32,
-block_offset: u16,
-num: u32,
-inode_type: InodeType,
-name: []const u8,
-
-pub fn readDir(alloc: std.mem.Allocator, rdr: *Reader, size: u32) ![]Entry {
-    var cur_red: u32 = 3; // start at 3 due to "." & ".." being counted in the dir size.
-    var hdr: Header = undefined;
-    var raw: RawEntry = undefined;
-    var out: std.ArrayList(Entry) = try .initCapacity(alloc, 100); // Start out with a decent capacity instead of needing to allocate per header.
-    errdefer out.deinit(alloc);
-    while (cur_red < size) {
-        try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
-        cur_red += @sizeOf(Header);
-        try out.ensureUnusedCapacity(alloc, hdr.count + 1);
-        for (0..hdr.count + 1) |_| {
-            try rdr.readSliceEndian(RawEntry, @ptrCast(&raw), .little);
-            const name = try alloc.alloc(u8, raw.name_size + 1);
-            errdefer alloc.free(name);
-            try rdr.readSliceEndian(u8, name, .little);
-            const val = out.addOneAssumeCapacity();
-            val.* = .{
-                .block_start = hdr.block_start,
-                .block_offset = raw.offset,
-                .num = @abs(hdr.num + raw.offset),
-                .inode_type = raw.inode_type,
-                .name = name,
-            };
-            cur_red += @sizeOf(RawEntry) + raw.name_size + 1;
-        }
-    }
-    return out.toOwnedSlice(alloc);
-}
-
-pub fn deinit(self: Entry, alloc: std.mem.Allocator) void {
-    alloc.free(self.name);
-}

src/directory.zig

@@ -0,0 +1,69 @@
+const std = @import("std");
+const Reader = std.Io.Reader;
+
+const Inode = @import("inode.zig");
+
+pub const Error = error{OutOfMemory} || Reader.Error;
+
+const DirEntry = @This();
+
+block_start: u32,
+block_offset: u16,
+type: Inode.Type,
+name: []const u8,
+
+pub fn deinit(self: DirEntry, alloc: std.mem.Allocator) void {
+    alloc.free(self.name);
+}
+
+pub fn readDirectory(alloc: std.mem.Allocator, rdr: *Reader, size: u32) Error![]DirEntry {
+    var hdr: Header = undefined;
+    var raw: RawEntry = undefined;
+    var out: std.ArrayList(DirEntry) = try .initCapacity(alloc, 30);
+    errdefer {
+        for (out.items) |ent|
+            alloc.free(ent.name);
+        out.deinit(alloc);
+    }
+
+    var tot_red: u32 = 3;
+    while (tot_red < size) {
+        try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
+        try out.ensureUnusedCapacity(alloc, hdr.count + 1);
+
+        tot_red += @sizeOf(Header);
+
+        for (0..hdr.count + 1) |_| {
+            try rdr.readSliceEndian(RawEntry, @ptrCast(&raw), .little);
+
+            const new_name = try alloc.alloc(u8, raw.name_size + 1);
+            try rdr.readSliceEndian(u8, new_name, .little);
+
+            const new = out.addOneAssumeCapacity();
+            new.* = .{
+                .block_start = hdr.block_start,
+                .block_offset = raw.block_offset,
+                .type = raw.type,
+                .name = new_name,
+            };
+
+            tot_red += @sizeOf(RawEntry) + raw.name_size + 1;
+        }
+    }
+    return out.toOwnedSlice(alloc);
+}
+
+// Types
+
+const Header = extern struct {
+    count: u32,
+    block_start: u32,
+    num: u32,
+};
+
+const RawEntry = extern struct {
+    block_offset: u16,
+    num_offset: i16,
+    type: Inode.Type,
+    name_size: u16,
+};

src/file.zig

@@ -1,202 +1,95 @@
-//! A file/directory within the squashfs archive.
+//! An easier to use wrapper around an inode.
 
 const std = @import("std");
-const File = std.fs.File;
-const WaitGroup = std.Thread.WaitGroup;
-const Mutex = std.Thread.Mutex;
+const Io = std.Io;
 
 const Archive = @import("archive.zig");
-const DirEntry = @import("dir_entry.zig");
+const DirEntry = @import("directory.zig");
 const ExtractionOptions = @import("options.zig");
 const Inode = @import("inode.zig");
-const BlockSize = @import("inode_data/file.zig").BlockSize;
-const DataReader = @import("util/data.zig");
+const DataExtractor = @import("util/data_extractor.zig");
+const Decompressor = @import("util/decompressor.zig");
 const MetadataReader = @import("util/metadata.zig");
+const SharedCache = @import("util/shared_cache.zig");
 
-const FileError = error{
-    NotDirectory,
-    NotRegularFile,
-    NotSymlink,
-    NotDevice,
-    NotFound,
-    ExtractionPathExists,
-};
+const File = @This();
 
-const SfsFile = @This();
+alloc: std.mem.Allocator,
 
-archive: *Archive,
+archive: Archive,
 
 inode: Inode,
 name: []const u8,
 
-/// Initialize a new File.
-/// name is copied to the File so can be safely freed afterwards.
-pub fn init(archive: *Archive, inode: Inode, name: []const u8) !SfsFile {
-    const new_name = try archive.allocator().alloc(u8, name.len);
+/// Creates a new File from an inode. Takes ownership of the Inode and creates a copy of the given name.
+/// Requires the given allocator was used to create the Inode.
+pub fn init(alloc: std.mem.Allocator, archive: Archive, in: Inode, name: []const u8) !File {
+    const new_name = try alloc.alloc(u8, name.len);
     @memcpy(new_name, name);
     return .{
+        .alloc = alloc,
+
         .archive = archive,
-        .inode = inode,
+
+        .inode = in,
         .name = new_name,
     };
 }
-pub fn fromEntry(archive: *Archive, entry: DirEntry) !SfsFile {
-    var rdr = try archive.fil.readerAt(entry.block_start + archive.super.inode_start, &[0]u8{});
-    var meta: MetadataReader = .init(archive.allocator(), &rdr.interface, archive.decomp);
-    try meta.interface.discardAll(entry.block_offset);
-    const inode: Inode = try .read(archive.allocator(), &meta.interface, archive.super.block_size);
-    errdefer inode.deinit(archive.allocator());
-    return .init(archive, inode, entry.name);
+pub fn fromDirEntry(alloc: std.mem.Allocator, io: Io, archive: Archive, ent: DirEntry) !File {
+    var rdr = try archive.file.readerAt(io, archive.super.inode_start + ent.block_start, &[0]u8{});
+    var meta: MetadataReader = .init(alloc, &rdr.interface, &archive.stateless_decomp);
+    try meta.interface.discardAll(ent.block_offset);
+
+    var in: Inode = try .read(alloc, &meta.interface, archive.super.block_size);
+    errdefer in.deinit(alloc);
+    return .init(alloc, archive, in, ent.name);
+}
+pub fn deinit(self: File) void {
+    self.alloc.free(self.name);
+    self.inode.deinit(self.alloc);
 }
 
-pub fn deinit(self: SfsFile) void {
-    var alloc = self.archive.allocator();
-    alloc.free(self.name);
-    self.inode.deinit(alloc);
-}
-
-fn getEntries(self: SfsFile) ![]DirEntry {
-    return self.inode.dirEntries(self.archive.allocator(), self.archive.*);
-}
-
-pub fn ownerUid(self: SfsFile) !u16 {
-    return self.archive.id(self.inode.hdr.uid_idx);
-}
-pub fn ownerGid(self: SfsFile) !u16 {
-    return self.archive.id(self.inode.hdr.gid_idx);
-}
-pub fn permissions(self: SfsFile) u16 {
-    return self.inode.hdr.permissions;
-}
-
-pub fn isRegular(self: SfsFile) bool {
-    return switch (self.inode.hdr.inode_type) {
-        .file, .ext_file => true,
-        else => false,
-    };
-}
-/// The returned DataReader will no longer work if the File's deinit function is called
-/// or, more specifically, it's inode's deinit function is called.
-pub fn dataReader(self: SfsFile) !DataReader {
-    return self.inode.dataReader(self.archive);
-}
-
-pub fn isDir(self: SfsFile) bool {
-    return switch (self.inode.hdr.inode_type) {
-        .dir, .ext_dir => true,
-        else => false,
-    };
-}
-pub fn iterate(self: SfsFile) !Iterator {
-    if (!self.isDir()) return FileError.NotDirectory;
-    return .{
-        .entries = try self.getEntries(),
-        .archive = self.archive,
-    };
-}
-/// Open a sub-file/folder within a directory at the given path.
-/// If path is "", ".", "/", or "./", this File is returned.
-pub fn open(self: SfsFile, alloc: std.mem.Allocator, path: []const u8) !SfsFile {
-    if (!self.isDir()) return FileError.NotDirectory;
-    if (pathIsSelf(path)) return self;
-
-    // Recursively stip ending & leading path separators.
-    if (path[0] == '/') return self.open(path[1..]);
-    if (path[path.len - 1] == '/') return self.open(path[0 .. path.len - 1]);
-
-    const idx = std.mem.indexOf(u8, path, "/") orelse path.len;
-    const first_element = path[0..idx];
-    if (std.mem.eql(u8, first_element, ".")) return self.open(path[idx + 1 ..]);
-    const entries = try self.getEntries();
+pub fn open(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8) !File {
+    const entries = try self.inode.readDirectory(
+        alloc,
+        io,
+        self.archive.file,
+        &self.archive.stateless_decomp,
+        self.archive.super.dir_start,
+    );
     defer {
-        for (entries) |e| {
-            e.deinit(alloc);
-        }
+        for (entries) |ent|
+            alloc.free(ent.name);
         alloc.free(entries);
     }
-    var cur_slice = entries;
-    var split = cur_slice.len / 2;
-    while (cur_slice.len > 0) {
-        split = cur_slice.len / 2;
-        const comp = std.mem.order(u8, first_element, cur_slice[split].name);
-        switch (comp) {
-            .eq => {
-                var fil: SfsFile = try .fromEntry(self.archive, cur_slice[split]);
-                if (idx == path.len) {
-                    return fil;
-                }
-                defer fil.deinit();
-                return fil.open(alloc, path[idx + 1 ..]);
-            },
-            .lt => cur_slice = cur_slice[0..split],
-            .gt => cur_slice = cur_slice[split + 1 ..],
+    const path = std.mem.trim(u8, filepath, "/");
+    const first_element: []const u8 = std.mem.sliceTo(path, '/');
+
+    var search_slice = entries;
+    var idx: usize = undefined;
+    while (search_slice.len > 0) {
+        idx = search_slice.len / 2;
+        const middle = search_slice[idx];
+        switch (std.mem.order(u8, first_element, middle.name)) {
+            .eq => break,
+            .lt => search_slice = search_slice[0..idx],
+            .gt => search_slice = search_slice[idx + 1 ..],
         }
-    }
-    return FileError.NotFound;
+    } else return Error.FileNotFound;
+
+    const first_elem_file = try fromDirEntry(alloc, io, self.archive, search_slice[idx]);
+    if (first_element.len == path.len)
+        return first_elem_file;
+    defer first_elem_file.deinit();
+    return first_elem_file.open(alloc, io, path[first_element.len + 1 ..]);
 }
 
-pub fn isSymlink(self: SfsFile) bool {
-    return switch (self.inode.hdr.inode_type) {
-        .symlink, .ext_symlink => true,
-        else => false,
-    };
-}
-pub fn symlinkPath(self: SfsFile) ![]const u8 {
-    if (!self.isSymlink()) return FileError.NotSymlink;
-    return switch (self.inode.data) {
-        .symlink => |s| s.target,
-        .ext_symlink => |s| s.target,
-        else => unreachable,
-    };
+pub fn extract(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8, options: ExtractionOptions) !void {
+    return self.inode.extract(alloc, io, self.archive.file, self.archive.super, filepath, options);
 }
 
-/// Check if the File is a block or character device.
-pub fn isDevice(self: SfsFile) bool {
-    return switch (self.inode.hdr.inode_type) {
-        .block_dev, .char_dev, .ext_block_dev, .ext_char_dev => true,
-        else => false,
-    };
-}
-/// If the File is a block or character device, get's it's device number.
-pub fn devNum(self: SfsFile) !u32 {
-    if (!self.isDevice()) return FileError.NotDevice;
-    return switch (self.inode.data) {
-        .block_dev, .char_dev => |d| d.dev,
-        .ext_block_dev, .ext_char_dev => |d| d.dev,
-        else => unreachable,
-    };
-}
+// Types
 
-/// Extract the given File to the path. If File is a regular file, the path must be a directory or not exist.
-/// If the gievn path is a folder, the File's contents will be extracted within.
-pub fn extract(self: *SfsFile, alloc: std.mem.Allocator, path: []const u8, options: ExtractionOptions) !void {
-    return self.inode.extractToThreaded(alloc, self.archive, path, options);
-}
-
-/// Utility function.
-pub fn pathIsSelf(path: []const u8) bool {
-    if (path.len == 0) return true;
-    if (path.len == 1 and (path[0] == '/' or path[0] == '.')) return true;
-    if (path.len == 2 and (path[0] == '.' and path[1] == '/')) return true;
-    return false;
-}
-
-pub const Iterator = struct {
-    entries: []DirEntry,
-    archive: *Archive,
-
-    idx: u32 = 0,
-
-    pub fn next(self: *Iterator) !?SfsFile {
-        if (self.idx >= self.entries.len) return null;
-        defer self.idx += 1;
-        return try SfsFile.fromEntry(self.archive, self.entries[self.idx]);
-    }
-    pub fn deinit(self: Iterator) void {
-        var alloc = self.archive.allocator();
-        for (self.entries) |e| {
-            e.deinit(alloc);
-        }
-        alloc.free(self.entries);
-    }
-};
+pub const Error = error{
+    FileNotFound,
+} || Inode.Error;

src/frag.zig

@@ -0,0 +1,7 @@
+const BlockSize = @import("inode_data/file.zig").BlockSize;
+
+pub const FragEntry = extern struct {
+    start: u64,
+    size: BlockSize,
+    _: u32,
+};

src/inode.zig

@@ -2,77 +2,30 @@
 
 const std = @import("std");
 const Reader = std.Io.Reader;
-const WaitGroup = std.Thread.WaitGroup;
-const Pool = std.Thread.Pool;
-const Mutex = std.Thread.Mutex;
+const Io = std.Io;
 
 const Archive = @import("archive.zig");
-const DirEntry = @import("dir_entry.zig");
+const Decomp = @import("decomp.zig").Decomp;
+const DirEntry = @import("directory.zig");
 const ExtractionOptions = @import("options.zig");
+const FragEntry = @import("frag.zig").FragEntry;
 const dir = @import("inode_data/dir.zig");
 const file = @import("inode_data/file.zig");
 const misc = @import("inode_data/misc.zig");
-const Tables = @import("tables.zig");
-const DataReader = @import("util/data.zig");
-const ThreadedDataReader = @import("util/data_threaded.zig");
-const InodeExtract = @import("util/extract.zig");
-const InodeFinish = @import("util/inode_finish.zig");
-const FinishUnion = InodeFinish.FinishUnion;
+const LookupTable = @import("lookup_table.zig");
+const CachedTable = LookupTable.CachedTable;
+const DataExtractor = @import("util/data_extractor.zig");
+const DataReader = @import("util/data_reader.zig");
+const Decompressor = @import("util/decompressor.zig");
 const MetadataReader = @import("util/metadata.zig");
-
-pub const Ref = packed struct {
-    block_offset: u16,
-    block_start: u32,
-    _: u16,
-};
-
-pub const InodeType = enum(u16) {
-    dir = 1,
-    file,
-    symlink,
-    block_dev,
-    char_dev,
-    fifo,
-    socket,
-    ext_dir,
-    ext_file,
-    ext_symlink,
-    ext_block_dev,
-    ext_char_dev,
-    ext_fifo,
-    ext_socket,
-};
-
-pub const InodeData = union(InodeType) {
-    dir: dir.Dir,
-    file: file.File,
-    symlink: misc.Symlink,
-    block_dev: misc.Dev,
-    char_dev: misc.Dev,
-    fifo: misc.IPC,
-    socket: misc.IPC,
-    ext_dir: dir.ExtDir,
-    ext_file: file.ExtFile,
-    ext_symlink: misc.ExtSymlink,
-    ext_block_dev: misc.ExtDev,
-    ext_char_dev: misc.ExtDev,
-    ext_fifo: misc.ExtIPC,
-    ext_socket: misc.ExtIPC,
-};
-
-pub const Header = packed struct {
-    inode_type: InodeType,
-    permissions: u16,
-    uid_idx: u16,
-    gid_idx: u16,
-    mod_time: u32,
-    num: u32,
-};
+const OffsetFile = @import("util/offset_file.zig");
+const SharedCache = @import("util/shared_cache.zig");
+const XattrTable = @import("xattr_table.zig");
 
 const Inode = @This();
 
 hdr: Header,
-data: InodeData,
+data: Data,
 
 pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Inode {
     var hdr: Header = undefined;
@@ -97,93 +50,463 @@ pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Inode {
         },
     };
 }
-pub fn readFromEntry(alloc: std.mem.Allocator, archive: Archive, entry: DirEntry) !Inode {
-    var rdr = try archive.fil.readerAt(archive.super.inode_start + entry.block_start, &[0]u8{});
-    var meta: MetadataReader = .init(alloc, &rdr.interface, archive.decomp);
-    try meta.interface.discardAll(entry.block_offset);
-    return read(alloc, &meta.interface, archive.super.block_size);
-}
-
 pub fn deinit(self: Inode, alloc: std.mem.Allocator) void {
     switch (self.data) {
-        .file => |f| alloc.free(f.block_sizes),
-        .ext_file => |f| alloc.free(f.block_sizes),
-        .symlink => |s| alloc.free(s.target),
-        .ext_symlink => |s| alloc.free(s.target),
+        .file => |d| d.deinit(alloc),
+        .symlink => |d| d.deinit(alloc),
+        .ext_file => |d| d.deinit(alloc),
+        .ext_symlink => |d| d.deinit(alloc),
         else => {},
     }
 }
 
-/// Get the data reader for a file inode.
-pub fn dataReader(self: Inode, alloc: std.mem.Allocator, archive: Archive, tables: *Tables) !DataReader {
-    return switch (self.hdr.inode_type) {
-        .file => readerFromData(alloc, archive, tables, self.data.file),
-        .ext_file => readerFromData(alloc, archive, tables, self.data.ext_file),
-        else => error.NotRegularFile,
-    };
-}
-fn readerFromData(alloc: std.mem.Allocator, archive: Archive, tables: *Tables, data: anytype) !DataReader {
-    var out: DataReader = .init(alloc, archive, data.block_sizes, data.block_start, data.size);
-    if (data.frag_idx != 0xFFFFFFFF)
-        out.addFragment(try tables.frag_table.get(data.frag_idx), data.frag_block_offset);
-    return out;
-}
+// Utility Functions
 
-/// Get the directory entries for a directory inode.
-pub fn dirEntries(self: Inode, alloc: std.mem.Allocator, archive: Archive) ![]DirEntry {
-    return switch (self.hdr.inode_type) {
-        .dir => entriesFromData(alloc, archive, self.data.dir),
-        .ext_dir => entriesFromData(alloc, archive, self.data.ext_dir),
-        else => error.NotDirectory,
-    };
-}
-fn entriesFromData(alloc: std.mem.Allocator, archive: Archive, data: anytype) ![]DirEntry {
-    var rdr = try archive.fil.readerAt(archive.super.dir_start + data.block_start, &[0]u8{});
-    var meta: MetadataReader = .init(alloc, &rdr.interface, archive.decomp);
-    try meta.interface.discardAll(data.block_offset);
-    return DirEntry.readDir(alloc, &meta.interface, data.size);
-}
-
-/// Returns the xattr index for the given inode. If the inode isn't an extended variant or doesn't have any, the u32 max is returned (0xFFFFFFFF).
-pub fn xattrIdx(self: Inode) u32 {
+/// Read the directory entries
+pub fn readDirectory(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, dir_offset: u64) ![]DirEntry {
     return switch (self.data) {
-        .ext_dir => |d| d.xattr_id,
-        .ext_file => |f| f.xattr_idx,
-        .ext_symlink => |s| s.xattr_idx,
-        .ext_block_dev, .ext_char_dev => |d| d.xattr_idx,
-        .ext_fifo, .ext_socket => |i| i.xattr_idx,
-        else => 0xFFFFFFFF,
+        .dir => |d| readDirFromData(alloc, io, fil, decomp, dir_offset, d),
+        .ext_dir => |d| readDirFromData(alloc, io, fil, decomp, dir_offset, d),
+        else => Error.NotDirectory,
     };
 }
+fn readDirFromData(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, dir_offset: u64, d: anytype) ![]DirEntry {
+    var rdr = try fil.readerAt(io, dir_offset + d.block_start, &[0]u8{});
+    var meta: MetadataReader = .init(alloc, &rdr.interface, decomp);
+    try meta.interface.discardAll(d.block_offset);
 
-/// Applies the Inode's metadata to the given File.
-/// Mod time is always set, but permissions and xattrs are set based on the given ExtractionOptions.
-pub fn setMetadata(self: Inode, alloc: std.mem.Allocator, tables: *Tables, fil: std.fs.File, options: ExtractionOptions) !void {
-    const time = @as(i128, self.hdr.mod_time) * 1000000000;
-    try fil.updateTimes(time, time);
-    if (!options.ignore_permissions) {
-        try fil.chmod(self.hdr.permissions);
-        try fil.chown(try tables.id_table.get(self.hdr.uid_idx), try tables.id_table.get(self.hdr.gid_idx));
+    return DirEntry.readDirectory(alloc, &meta.interface, d.size);
+}
+/// Get a reader for a regular file's data.
+pub fn dataReader(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32) !DataReader {
+    return switch (self.data) {
+        .file => |f| getReaderFromData(alloc, io, fil, cache, decomp, block_size, f),
+        .ext_file => |f| getReaderFromData(alloc, io, fil, cache, decomp, block_size, f),
+        else => Error.NotRegularFile,
+    };
+}
+fn getReaderFromData(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32, d: anytype) !DataReader {
+    const ext: DataReader = .init(alloc, io, fil, cache, decomp, block_size, d.size, d.block_start, d.blocks);
+    if (d.frag_block_offset == 0xFFFFFFFF) {
+        // TODO:
+        return error.TODO;
     }
-    if (!options.ignore_xattr) {
-        const idx = self.xattrIdx();
-        if (idx == 0xFFFFFFFF) return;
-        const xattrs = try tables.xattr_table.get(alloc, idx);
-        defer alloc.free(xattrs);
-        for (xattrs) |kv| {
-            const res = std.os.linux.fsetxattr(fil.handle, kv.key, kv.value.ptr, kv.value.len, 0);
-            alloc.free(kv.key);
-            alloc.free(kv.value);
-            if (res != 0) {
-                if (options.verbose)
-                    options.verbose_writer.?.print("fsetxattr has result of: {}\n", .{res}) catch {};
-                return error.SetXattr;
+    return ext;
+}
+/// Get an extractor for a regular file's data.
+pub fn dataExtractor(self: Inode, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32) !DataExtractor {
+    return switch (self.data) {
+        .file => |f| getExtractorFromData(fil, cache, decomp, block_size, f),
+        .ext_file => |f| getExtractorFromData(fil, cache, decomp, block_size, f),
+        else => Error.NotRegularFile,
+    };
+}
+fn getExtractorFromData(fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32, d: anytype) !DataExtractor {
+    const ext: DataExtractor = .init(fil, cache, decomp, block_size, d.size, d.block_start, d.blocks);
+    if (d.frag_block_offset == 0xFFFFFFFF) {
+        // TODO:
+        return error.TODO;
+    }
+    return ext;
+}
+/// Get a symlink's target path
+pub fn symlinkTarget(self: Inode) ![]const u8 {
+    return switch (self.data) {
+        .symlink => |s| s.target,
+        .ext_symlink => |s| s.target,
+        else => Error.NotSymlink,
+    };
+}
+/// Get inode's gid
+pub fn gid(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, id_table_start: u64) !u16 {
+    return LookupTable.lookupValue(u16, alloc, io, decomp, fil, id_table_start, self.hdr.gid_idx);
+}
+/// Get inode's uid
+pub fn uid(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, id_table_start: u64) !u16 {
+    return LookupTable.lookupValue(u16, alloc, io, decomp, fil, id_table_start, self.hdr.uid_idx);
+}
+/// Get the inode's xattr values as an index into the Archive's xattr table.
+/// Returns error.NoXattr if the inode doesn't have extended attributes.
+pub fn xattrIndex(self: Inode) !u32 {
+    const idx = switch (self.data) {
+        .ext_dir => |e| e.xattr_idx,
+        .ext_file => |e| e.xattr_idx,
+        .ext_symlink => |e| e.xattr_idx,
+        .ext_block_dev => |e| e.xattr_idx,
+        .ext_char_dev => |e| e.xattr_idx,
+        .ext_fifo => |e| e.xattr_idx,
+        .ext_socket => |e| e.xattr_idx,
+        else => Error.NoXattr,
+    };
+    if (idx == 0xFFFFFFFF) return Error.NoXattr;
+    return idx;
+}
+// Get an inode's xattr values. If the inode does not have xattr values (including if the inode is not an extended type), an empty slice is returned.
+pub fn xattrValues(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, xattr_table_start: u64) ![]XattrTable.XattrOwned {
+    const idx = self.xattrIndex() catch &[0]XattrTable.XattrOwned{};
+    return XattrTable.statelessLookup(alloc, io, decomp, fil, xattr_table_start, idx);
+}
+
+// Types
+
+pub const Error = error{
+    NotDirectory,
+    NotRegularFile,
+    NotSymlink,
+    NotExtended,
+};
+
+pub const Ref = packed struct(u64) {
+    block_offset: u16,
+    block_start: u32,
+    _: u16 = 0,
+};
+
+pub const Type = enum(u16) {
+    dir = 1,
+    file,
+    symlink,
+    block_dev,
+    char_dev,
+    fifo,
+    socket,
+    ext_dir,
+    ext_file,
+    ext_symlink,
+    ext_block_dev,
+    ext_char_dev,
+    ext_fifo,
+    ext_socket,
+};
+
+pub const Data = union(Type) {
+    dir: dir.Dir,
+    file: file.File,
+    symlink: misc.Symlink,
+    block_dev: misc.Dev,
+    char_dev: misc.Dev,
+    fifo: misc.IPC,
+    socket: misc.IPC,
+    ext_dir: dir.ExtDir,
+    ext_file: file.ExtFile,
+    ext_symlink: misc.ExtSymlink,
+    ext_block_dev: misc.ExtDev,
+    ext_char_dev: misc.ExtDev,
+    ext_fifo: misc.ExtIPC,
+    ext_socket: misc.ExtIPC,
+};
+
+pub const Header = extern struct {
+    inode_type: Type,
+    permissions: u16,
+    uid_idx: u16,
+    gid_idx: u16,
+    mod_time: u32,
+    num: u32,
+};
+
+// Extract
+
+const ExtractError = error{ MknodFailed, CannotSetXattr, ConcurrencyUnavailable } || DataExtractor.Error || Io.Dir.CreateFileAtomicError || LookupTable.Error ||
+    Io.File.Reader.SeekError || Io.File.Atomic.LinkError || Io.Dir.CreateDirError || Io.File.OpenError ||
+    Io.File.SetPermissionsError || Io.File.SetOwnerError || Io.Dir.SymLinkError || Io.Dir.CreateDirPathError;
+const PathRet = struct {
+    path: []const u8,
+    inode: Inode,
+    xattr_idx: ?u32 = null,
+};
+const ExtractReturnUnion = union(enum) {
+    path_ret: ExtractError!PathRet,
+};
+const Tables = struct {
+    id: LookupTable.CachedTable(u16),
+    frag: LookupTable.CachedTable(FragEntry),
+    xattr: XattrTable,
+};
+
+/// Extracts the given inode to the given path. If the inode not a directory, the given path must not exist.
+/// If the inode is a directory the path must not exist or be a directory.
+pub fn extract(
+    self: Inode,
+    alloc: std.mem.Allocator,
+    io: Io,
+    fil: OffsetFile,
+    super: Archive.Superblock,
+    filepath: []const u8,
+    options: ExtractionOptions,
+) !void {
+    const path = std.mem.trimEnd(u8, filepath, "/");
+
+    var decomp_base: Decomp = switch (super.compression) {
+        .gzip => .{ .gzip = try .init(alloc, super.block_size) },
+        .lzma => .{ .lzma = try .init(alloc, super.block_size) },
+        .xz => .{ .xz = try .init(alloc, super.block_size) },
+        .zstd => .{ .zstd = try .init(alloc, io, super.block_size) },
+        else => unreachable,
+    };
+    defer decomp_base.deinit();
+    const decomp = decomp_base.decompressor();
+
+    var frag_table: CachedTable(FragEntry) = .init(alloc, fil, decomp, super.frag_start, super.frag_count);
+    defer if (!options.ignore_permissions) frag_table.deinit(io);
+    try frag_table.fill(io);
+
+    var arena: std.heap.ArenaAllocator = .init(alloc);
+    defer arena.deinit();
+
+    var sel_buf = [1]ExtractReturnUnion{undefined} ** 10;
+    var sel: Io.Select(ExtractReturnUnion) = .init(io, &sel_buf);
+    defer sel.cancelDiscard();
+
+    switch (self.hdr.inode_type) {
+        .dir, .ext_dir => try sel.concurrent(
+            .path_ret,
+            extractDir,
+            .{ self, alloc, io, fil, decomp, &sel, &arena, super.dir_start, super.inode_start, &frag_table, super.block_size, path },
+        ),
+        .file, .ext_file => try sel.concurrent(
+            .path_ret,
+            extractFile,
+            .{ self, alloc, io, fil, decomp, &frag_table, super.block_size, path },
+        ),
+        .symlink, .ext_symlink => try sel.concurrent(.path_ret, extractSymlink, .{ self, io, path }),
+        else => if (@hasField(std.os, "linux"))
+            try sel.concurrent(.path_ret, extractDevOrIPC, .{ self, alloc, path }),
+    }
+
+    var xattr_table: ?XattrTable = if (!options.ignore_xattr)
+        try .init(alloc, io, fil, decomp, super.xattr_start)
+    else
+        null;
+    defer if (!options.ignore_xattr) xattr_table.?.deinit(io);
+    if (xattr_table != null) try xattr_table.?.table.fill(io);
+
+    var id_table: ?CachedTable(u16) = if (!options.ignore_xattr)
+        .init(alloc, fil, decomp, super.id_start, super.id_count)
+    else
+        null;
+    defer if (!options.ignore_xattr) id_table.?.deinit(io);
+    if (id_table != null) try id_table.?.fill(io);
+
+    while (true) {
+        const group_token = sel.group.token.load(.acquire);
+        if (group_token == null) break;
+        // std.debug.print("{any}\n", .{sel.group.state});
+
+        // std.debug.print("Waiting for return...", .{});
+        const ret = try sel.await();
+        // std.debug.print("Got One...\n", .{});
+        const path_ret = try ret.path_ret;
+
+        if (options.ignore_permissions and options.ignore_xattr) continue;
+        if (options.ignore_permissions and path_ret.xattr_idx == null) continue;
+
+        var ret_file = try Io.Dir.cwd().openFile(io, path_ret.path, .{});
+        defer ret_file.close(io);
+
+        if (!options.ignore_permissions) {
+            try ret_file.setPermissions(io, @enumFromInt(path_ret.inode.hdr.permissions));
+            try ret_file.setOwner(
+                io,
+                try id_table.?.get(io, path_ret.inode.hdr.uid_idx),
+                try id_table.?.get(io, path_ret.inode.hdr.gid_idx),
+            );
+        }
+        if (@hasField(std.os, "linux") and !options.ignore_xattr and path_ret.xattr_idx != null) {
+            const xattrs = try xattr_table.?.get(alloc, io, path_ret.xattr_idx.?);
+            defer {
+                for (xattrs) |x|
+                    alloc.free(x.key);
+                alloc.free(xattrs);
+            }
+
+            for (xattrs) |x| {
+                const res = std.os.linux.fsetxattr(ret_file.handle, x.key, x.value.ptr, x.value.len, 0);
+                if (res != 0)
+                    return error.CannotSetXattr;
             }
         }
     }
 }
+fn extractDir(
+    self: Inode,
+    alloc: std.mem.Allocator,
+    io: Io,
+    fil: OffsetFile,
+    decomp: *const Decompressor,
+    parent_select: *Io.Select(ExtractReturnUnion),
+    arena: *std.heap.ArenaAllocator,
+    dir_start: u64,
+    inode_start: u64,
+    frag: *CachedTable(FragEntry),
+    block_size: u32,
+    path: []const u8,
+) ExtractError!PathRet {
+    try Io.Dir.cwd().createDirPath(io, path);
 
-/// Extract the inode to the given path.
-pub fn extractTo(self: Inode, alloc: std.mem.Allocator, archive: Archive, path: []const u8, options: ExtractionOptions) !void {
-    return InodeExtract.extractTo(alloc, self, archive, path, options);
+    var sel_buf = [1]ExtractReturnUnion{undefined} ** 10;
+    var sel: Io.Select(ExtractReturnUnion) = .init(io, &sel_buf);
+    defer sel.cancelDiscard();
+
+    var num: usize = 0;
+    {
+        const dir_entries = self.readDirectory(alloc, io, fil, decomp, dir_start) catch |err| switch (err) {
+            Error.NotDirectory => unreachable,
+            else => return @errorCast(err),
+        };
+        num = dir_entries.len;
+        defer {
+            for (dir_entries) |d|
+                d.deinit(alloc);
+            alloc.free(dir_entries);
+        }
+
+        for (dir_entries) |d| {
+            var rdr = try fil.readerAt(io, d.block_start + inode_start, &[0]u8{});
+            var meta_rdr: MetadataReader = .init(alloc, &rdr.interface, decomp);
+            try meta_rdr.interface.discardAll(d.block_offset);
+            const inode = try read(arena.allocator(), &meta_rdr.interface, block_size);
+            errdefer inode.deinit(arena.allocator());
+
+            const new_path = try std.mem.concat(arena.allocator(), u8, &[_][]const u8{ path, "/", d.name });
+            errdefer arena.allocator().free(new_path);
+
+            switch (d.type) {
+                .dir => try sel.concurrent(
+                    .path_ret,
+                    extractDir,
+                    .{ inode, alloc, io, fil, decomp, parent_select, arena, dir_start, inode_start, frag, block_size, new_path },
+                ),
+                .file => try sel.concurrent(
+                    .path_ret,
+                    extractFile,
+                    .{ inode, alloc, io, fil, decomp, frag, block_size, new_path },
+                ),
+                .symlink => try sel.concurrent(.path_ret, extractSymlink, .{ inode, io, new_path }),
+                else => try sel.concurrent(.path_ret, extractDevOrIPC, .{ inode, alloc, new_path }),
+            }
+        }
+    }
+
+    while (num > 0) {
+        const ret = sel.await() catch break;
+        num -= 1;
+
+        parent_select.queue.putOne(io, ret) catch |err| switch (err) {
+            error.Canceled => return error.Canceled,
+            else => break,
+        };
+    }
+    return .{
+        .path = path,
+        .inode = self,
+    };
+}
+fn extractFile(
+    self: Inode,
+    alloc: std.mem.Allocator,
+    io: Io,
+    fil: OffsetFile,
+    decomp: *const Decompressor,
+    frag: *CachedTable(FragEntry),
+    block_size: u32,
+    path: []const u8,
+) ExtractError!PathRet {
+    var atomic = try Io.Dir.cwd().createFileAtomic(io, path, .{});
+    defer atomic.deinit(io);
+
+    var ret: PathRet = .{
+        .inode = self,
+        .path = path,
+    };
+    const data: DataExtractor = blk: {
+        switch (self.data) {
+            .file => |f| {
+                var data: DataExtractor = .init(fil, decomp, block_size, f.size, f.block_start, f.block_sizes);
+                if (f.frag_idx != 0xFFFFFFFF)
+                    data.addFrag(f.frag_block_offset, try frag.get(io, f.frag_idx));
+
+                break :blk data;
+            },
+            .ext_file => |f| {
+                if (f.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = f.xattr_idx;
+                var data: DataExtractor = .init(fil, decomp, block_size, f.size, f.block_start, f.block_sizes);
+                if (f.frag_idx != 0xFFFFFFFF)
+                    data.addFrag(f.frag_block_offset, try frag.get(io, f.frag_idx));
+
+                break :blk data;
+            },
+            else => unreachable,
+        }
+    };
+
+    try data.extractAsync(alloc, io, atomic.file);
+    try atomic.link(io);
+
+    return ret;
+}
+fn extractSymlink(self: Inode, io: Io, path: []const u8) ExtractError!PathRet {
+    const target = switch (self.data) {
+        .symlink => |s| s.target,
+        .ext_symlink => |s| s.target,
+        else => unreachable,
+    };
+
+    try Io.Dir.cwd().symLink(io, target, path, .{});
+
+    return .{
+        .path = path,
+        .inode = self,
+    };
+}
+fn extractDevOrIPC(self: Inode, alloc: std.mem.Allocator, path: []const u8) ExtractError!PathRet {
+    var dev_num: u32 = 0;
+    var mode: u32 = 0;
+
+    const DT = std.posix.DT;
+
+    var ret: PathRet = .{
+        .inode = self,
+        .path = path,
+    };
+
+    switch (self.data) {
+        .block_dev => |d| {
+            dev_num = d.dev;
+            mode = DT.BLK;
+        },
+        .ext_block_dev => |d| {
+            dev_num = d.dev;
+            mode = DT.BLK;
+            if (d.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = d.xattr_idx;
+        },
+        .char_dev => |d| {
+            dev_num = d.dev;
+            mode = DT.CHR;
+        },
+        .ext_char_dev => |d| {
+            dev_num = d.dev;
+            mode = DT.CHR;
+            if (d.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = d.xattr_idx;
+        },
+        .fifo => mode = DT.FIFO,
+        .ext_fifo => |f| {
+            mode = DT.FIFO;
+            if (f.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = f.xattr_idx;
+        },
+        .socket => mode = DT.SOCK,
+        .ext_socket => |s| {
+            mode = DT.SOCK;
+            if (s.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = s.xattr_idx;
+        },
+        else => unreachable,
+    }
+
+    const sentinel_path = try std.mem.concatWithSentinel(alloc, u8, &[_][]const u8{path}, 0);
+    defer alloc.free(sentinel_path);
+
+    const res = std.os.linux.mknod(sentinel_path, mode, dev_num);
+    if (res != 0) return ExtractError.MknodFailed;
+
+    return ret;
 }

src/inode_data/dir.zig

@@ -1,6 +1,6 @@
 const Reader = @import("std").Io.Reader;
 
-pub const Dir = packed struct {
+pub const Dir = extern struct {
     block_start: u32,
     hard_links: u32,
     size: u16,
@@ -14,19 +14,19 @@ pub const Dir = packed struct {
     }
 };
 
-pub const ExtDir = packed struct {
+pub const ExtDir = extern struct {
     hard_links: u32,
     size: u32,
     block_start: u32,
     parent_num: u32,
     idx_count: u16,
     block_offset: u16,
-    xattr_id: u32,
+    xattr_idx: u32,
     // index: []DirIndex
 
     pub fn read(rdr: *Reader) !ExtDir {
         var d: ExtDir = undefined;
-        try rdr.readSliceEndian(Dir, @ptrCast(&d), .little);
+        try rdr.readSliceEndian(ExtDir, @ptrCast(&d), .little);
         return d;
     }
 };

src/inode_data/file.zig

@@ -1,34 +1,43 @@
 const std = @import("std");
 const Reader = std.Io.Reader;
 
-pub const BlockSize = packed struct {
+pub const BlockSize = packed struct(u32) {
     size: u24,
     uncompressed: bool,
     _: u7,
 };
 
+const FileRawRead = extern struct {
+    block_start: u32,
+    frag_idx: u32,
+    frag_block_offset: u32,
+    size: u32,
+};
+
 pub const File = struct {
-    block_start: u32, // bytes 0-3
-    frag_idx: u32, // bytes 4-7
-    frag_block_offset: u32, // bytes 8-11
-    size: u32, // bytes 12-15
+    block_start: u32,
+    frag_idx: u32,
+    frag_block_offset: u32,
+    size: u32,
     block_sizes: []BlockSize,
 
     pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !File {
-        var start: [16]u8 = undefined;
-        try rdr.readSliceAll(&start);
-        const frag_idx: u32 = std.mem.readInt(u32, start[4..8], .little);
-        const size: u32 = std.mem.readInt(u32, start[12..16], .little);
-        var num_blocks: u32 = size / block_size;
-        if (size % block_size != 0 and frag_idx == 0xFFFFFFFF) num_blocks += 1;
+        var raw: FileRawRead = undefined;
+        try rdr.readSliceEndian(FileRawRead, @ptrCast(&raw), .little);
+
+        var num_blocks: u32 = raw.size / block_size;
+        if (raw.size % block_size != 0 and raw.frag_idx == 0xFFFFFFFF)
+            num_blocks += 1;
+
         const sizes = try alloc.alloc(BlockSize, num_blocks);
         errdefer alloc.free(sizes);
         try rdr.readSliceEndian(BlockSize, sizes, .little);
+
         return .{
-            .block_start = std.mem.readInt(u32, start[0..4], .little),
-            .frag_idx = frag_idx,
-            .frag_block_offset = std.mem.readInt(u32, start[8..12], .little),
-            .size = size,
+            .block_start = raw.block_start,
+            .frag_idx = raw.frag_idx,
+            .frag_block_offset = raw.frag_block_offset,
+            .size = raw.size,
             .block_sizes = sizes,
         };
     }
@@ -38,34 +47,46 @@ pub const File = struct {
     }
 };
 
+const ExtFileRawRead = extern struct {
+    block_start: u64,
+    size: u64,
+    sparse: u64,
+    hard_links: u32,
+    frag_idx: u32,
+    frag_block_offset: u32,
+    xattr_idx: u32,
+};
+
 pub const ExtFile = struct {
-    block_start: u64, // bytes 0-7
-    size: u64, // bytes 8-15
-    sparse: u64, // bytes 16-23
-    hard_links: u32, // bytes 24-27
-    frag_idx: u32, // bytes 28-31
-    frag_block_offset: u32, // bytes 32-35
-    xattr_idx: u32, // bytes 36-39
+    block_start: u64,
+    size: u64,
+    sparse: u64,
+    hard_links: u32,
+    frag_idx: u32,
+    frag_block_offset: u32,
+    xattr_idx: u32,
     block_sizes: []BlockSize,
 
     pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !ExtFile {
-        var start: [40]u8 = undefined;
-        try rdr.readSliceAll(&start);
-        const frag_idx: u32 = std.mem.readInt(u32, start[28..32], .little);
-        const size: u64 = std.mem.readInt(u64, start[8..16], .little);
-        var num_blocks: u32 = @truncate(size / block_size);
-        if (size % block_size != 0 and frag_idx == 0xFFFFFFFF) num_blocks += 1;
+        var raw: ExtFileRawRead = undefined;
+        try rdr.readSliceEndian(ExtFileRawRead, @ptrCast(&raw), .little);
+
+        var num_blocks: u32 = @truncate(raw.size / block_size);
+        if (raw.size % block_size != 0 and raw.frag_idx == 0xFFFFFFFF)
+            num_blocks += 1;
+
         const sizes = try alloc.alloc(BlockSize, num_blocks);
         errdefer alloc.free(sizes);
         try rdr.readSliceEndian(BlockSize, sizes, .little);
+
         return .{
-            .block_start = std.mem.readInt(u64, start[0..8], .little),
-            .size = size,
-            .sparse = std.mem.readInt(u64, start[16..24], .little),
-            .hard_links = std.mem.readInt(u32, start[24..28], .little),
-            .frag_idx = frag_idx,
-            .frag_block_offset = std.mem.readInt(u32, start[32..36], .little),
-            .xattr_idx = std.mem.readInt(u32, start[36..40], .little),
+            .block_start = raw.block_start,
+            .size = raw.size,
+            .sparse = raw.sparse,
+            .hard_links = raw.hard_links,
+            .frag_idx = raw.frag_idx,
+            .frag_block_offset = raw.frag_block_offset,
+            .xattr_idx = raw.xattr_idx,
             .block_sizes = sizes,
         };
     }

src/inode_data/misc.zig

@@ -50,7 +50,7 @@ pub const ExtSymlink = struct {
 };
 
 /// A block or character device.
-pub const Dev = packed struct {
+pub const Dev = extern struct {
     hard_links: u32,
     dev: u32,
 
@@ -62,7 +62,7 @@ pub const Dev = packed struct {
 };
 
 /// An extended block or character device.
-pub const ExtDev = packed struct {
+pub const ExtDev = extern struct {
     hard_links: u32,
     dev: u32,
     xattr_idx: u32,
@@ -75,7 +75,7 @@ pub const ExtDev = packed struct {
 };
 
 /// A socket or FIFO file.
-pub const IPC = packed struct {
+pub const IPC = extern struct {
     hard_links: u32,
 
     pub fn read(rdr: *Reader) !IPC {
@@ -86,7 +86,7 @@ pub const IPC = packed struct {
 };
 
 /// An extended socket or FIFO file.
-pub const ExtIPC = packed struct {
+pub const ExtIPC = extern struct {
     hard_links: u32,
     xattr_idx: u32,
 

src/lookup_table.zig

@@ -0,0 +1,122 @@
+const std = @import("std");
+const Io = std.Io;
+
+const Decompressor = @import("util/decompressor.zig");
+const MetadataReader = @import("util/metadata.zig");
+const OffsetFile = @import("util/offset_file.zig");
+
+pub fn lookupValue(comptime T: anytype, alloc: std.mem.Allocator, io: Io, decomp: *const Decompressor, file: OffsetFile, table_start: u64, idx: u32) !T {
+    const T_PER_BLOCK: u16 = 8192 / @sizeOf(T);
+
+    const block = idx / T_PER_BLOCK;
+    const block_offset = idx % T_PER_BLOCK;
+
+    var rdr = try file.readerAt(io, table_start + (8 * block), &[0]u8{});
+    var offset: u64 = undefined;
+    try rdr.interface.readSliceEndian(u64, @ptrCast(&offset), .little);
+
+    rdr = try file.readerAt(io, offset, &[0]u8{});
+    var meta: MetadataReader = .init(alloc, &rdr.interface, decomp);
+
+    try meta.interface.discardAll(@sizeOf(T) * block_offset);
+    var out: T = undefined;
+    try meta.interface.readSliceEndian(T, @ptrCast(&out), .little);
+    return out;
+}
+
+pub const Error = Io.Cancelable || Io.File.Reader.SeekError || Io.Reader.ReadAllocError;
+
+pub fn CachedTable(comptime T: anytype) type {
+    return struct {
+        const T_PER_BLOCK: u16 = 8192 / @sizeOf(T);
+
+        const Table = @This();
+
+        alloc: std.mem.Allocator,
+        fil: OffsetFile,
+        decomp: *const Decompressor,
+
+        table_start: u64,
+        total_num: u32,
+
+        table: std.AutoHashMap(u32, []T),
+
+        mut: Io.Mutex = .init,
+
+        pub fn init(alloc: std.mem.Allocator, fil: OffsetFile, decomp: *const Decompressor, offset: u64, total_num: u32) Table {
+            return .{
+                .alloc = alloc,
+                .fil = fil,
+                .decomp = decomp,
+
+                .table_start = offset,
+                .total_num = total_num,
+
+                .table = .init(alloc),
+            };
+        }
+        pub fn deinit(self: *Table, io: Io) void {
+            self.mut.lockUncancelable(io);
+            var iter = self.table.valueIterator();
+            while (iter.next()) |val|
+                self.alloc.free(val.*);
+            self.table.deinit();
+        }
+
+        pub fn fill(self: *Table, io: Io) Error!void {
+            try self.mut.lock(io);
+            defer self.mut.unlock(io);
+
+            var num_blocks = self.total_num / T_PER_BLOCK;
+            if (self.total_num % T_PER_BLOCK > 0)
+                num_blocks += 1;
+
+            for (0..num_blocks) |block| {
+                var rdr = try self.fil.readerAt(io, self.table_start + (8 * block), &[0]u8{});
+                var offset: u64 = undefined;
+                try rdr.interface.readSliceEndian(u64, @ptrCast(&offset), .little);
+
+                const len: u16 = if (self.total_num % T_PER_BLOCK != 0 and block == (self.total_num - 1) / T_PER_BLOCK)
+                    @truncate(self.total_num % T_PER_BLOCK)
+                else
+                    T_PER_BLOCK;
+
+                rdr = try self.fil.readerAt(io, offset, &[0]u8{});
+                var meta: MetadataReader = .init(self.alloc, &rdr.interface, self.decomp);
+
+                const slice = try meta.interface.readSliceEndianAlloc(self.alloc, T, len, .little);
+                try self.table.put(@truncate(block), slice);
+            }
+        }
+
+        pub fn get(self: *Table, io: Io, idx: u32) Error!T {
+            const block = idx / T_PER_BLOCK;
+            const block_offset = idx % T_PER_BLOCK;
+            if (self.table.contains(block))
+                return self.table.get(block).?[block_offset];
+
+            try self.mut.lock(io);
+            defer self.mut.unlock(io);
+
+            if (self.table.contains(block))
+                return self.table.get(block).?[block_offset];
+
+            var rdr = try self.fil.readerAt(io, self.table_start + (8 * block), &[0]u8{});
+            var offset: u64 = undefined;
+            try rdr.interface.readSliceEndian(u64, @ptrCast(&offset), .little);
+
+            const len: u16 = if (self.total_num % T_PER_BLOCK != 0 and block == (self.total_num - 1) / T_PER_BLOCK)
+                @truncate(self.total_num % T_PER_BLOCK)
+            else
+                T_PER_BLOCK;
+
+            rdr = try self.fil.readerAt(io, offset, &[0]u8{});
+            var meta: MetadataReader = .init(self.alloc, &rdr.interface, self.decomp);
+
+            const slice = try meta.interface.readSliceEndianAlloc(self.alloc, T, len, .little);
+            try self.table.put(block, slice);
+
+            return slice[block_offset];
+        }
+    };
+}

src/options.zig

@@ -6,7 +6,7 @@ const Writer = std.Io.Writer;
 const ExtractionOptions = @This();
 
 /// The number of threads used for extraction. 0 implies single threaded.
-threads: usize = 1,
+threads: usize = 1, // TODO: Update to better integrate with zig 0.16 Io. Maybe limit to only single or multi-threaded.
 /// Don't set the file's owner & permissions after extraction
 ignore_permissions: bool = false,
 /// Don't set xattr values. Currently xattrs are never set anyway.

src/super.zig

@@ -1,69 +0,0 @@
-const std = @import("std");
-const math = std.math;
-
-const InodeRef = @import("inode.zig").Ref;
-
-const SQUASHFS_MAGIC: u32 = std.mem.readInt(u32, "hsqs", .little);
-
-const SuperblockError = error{
-    InvalidMagic,
-    InvalidBlockLog,
-    InvalidVersion,
-    InvalidCheck,
-};
-
-/// A squashfs Superblock
-pub const Superblock = packed struct {
-    magic: u32,
-    inode_count: u32,
-    mod_time: u32,
-    block_size: u32,
-    frag_count: u32,
-    compression: enum(u16) {
-        gzip = 1,
-        lzma,
-        lzo,
-        xz,
-        lz4,
-        zstd,
-    },
-    block_log: u16,
-    flags: packed struct {
-        inode_uncompressed: bool,
-        data_uncompressed: bool,
-        check: bool,
-        frag_uncompressed: bool,
-        fragment_never: bool,
-        fragment_always: bool,
-        duplicates: bool,
-        exportable: bool,
-        xattr_uncompressed: bool,
-        xattr_never: bool,
-        compression_options: bool,
-        ids_uncompressed: bool,
-        _: u4,
-    },
-    id_count: u16,
-    ver_maj: u16,
-    ver_min: u16,
-    root_ref: InodeRef,
-    size: u64,
-    id_start: u64,
-    xattr_start: u64,
-    inode_start: u64,
-    dir_start: u64,
-    frag_start: u64,
-    export_start: u64,
-
-    /// Validate the Superblock. If an error is returned, it's likely the archive is corrupted or not a squashfs archive.
-    pub fn validate(self: Superblock) !void {
-        if (self.magic != SQUASHFS_MAGIC)
-            return SuperblockError.InvalidMagic;
-        if (self.flags.check)
-            return SuperblockError.InvalidCheck;
-        if (self.ver_maj != 4 or self.ver_min != 0)
-            return SuperblockError.InvalidVersion;
-        if (math.log2(self.block_size) != self.block_log)
-            return SuperblockError.InvalidBlockLog;
-    }
-};

src/tables.zig

@@ -1,107 +0,0 @@
-const std = @import("std");
-const Mutex = std.Thread.Mutex;
-
-const Archive = @import("archive.zig");
-const BlockSize = @import("inode_data/file.zig").BlockSize;
-const InodeRef = @import("inode.zig").Ref;
-const Superblock = @import("super.zig").Superblock;
-const MetadataReader = @import("util/metadata.zig");
-const OffsetFile = @import("util/offset_file.zig");
-const XattrTable = @import("xattr.zig");
-
-/// Information about a fragment section. Multiple fragments are contained in the block described by a single FragEntry.
-/// The offset into the block and fragment size is stored in the file's inode.
-pub const FragEntry = packed struct {
-    start: u64,
-    size: BlockSize,
-    _: u32,
-};
-
-const Tables = @This();
-
-frag_table: Table(FragEntry),
-id_table: Table(u16),
-export_table: Table(InodeRef),
-xattr_table: XattrTable,
-
-pub fn init(alloc: std.mem.Allocator, archive: Archive) !Tables {
-    return .{
-        .frag_table = try .init(alloc, archive.fil, archive.decomp, archive.super.frag_start, archive.super.frag_count),
-        .id_table = try .init(alloc, archive.fil, archive.decomp, archive.super.id_start, archive.super.id_count),
-        .export_table = try .init(alloc, archive.fil, archive.decomp, archive.super.export_start, archive.super.inode_count),
-        .xattr_table = try .init(alloc, archive.fil, archive.decomp, archive.super.xattr_start),
-    };
-}
-pub fn deinit(self: *Tables) void {
-    self.frag_table.deinit();
-    self.id_table.deinit();
-    self.export_table.deinit();
-    self.xattr_table.deinit();
-}
-
-/// A two-layer metadata table.
-pub fn Table(T: anytype) type {
-    return struct {
-        const Self = @This();
-
-        const VALS_PER_BLOCK = 8192 / @sizeOf(T);
-
-        alloc: std.mem.Allocator,
-        fil: OffsetFile,
-        decomp: DecompFn,
-        tab_start: u64,
-
-        tab: std.AutoHashMap(u32, []T),
-        values: u32,
-
-        mut: Mutex = .{},
-
-        pub fn init(alloc: std.mem.Allocator, fil: OffsetFile, decomp: DecompFn, tab_start: u64, values: u32) !Self {
-            return .{
-                .alloc = alloc,
-                .fil = fil,
-                .decomp = decomp,
-                .tab_start = tab_start,
-
-                .tab = .init(alloc),
-                .values = values,
-            };
-        }
-
-        pub fn deinit(self: *Self) void {
-            var iter = self.tab.valueIterator();
-            while (iter.next()) |s| {
-                self.alloc.free(s.*);
-            }
-            self.tab.deinit();
-        }
-
-        pub fn get(self: *Self, idx: u32) !T {
-            if (idx >= self.values) return error.InvalidIndex;
-            const block_num = idx / VALS_PER_BLOCK;
-            const idx_offset = idx - (block_num * VALS_PER_BLOCK);
-            if (self.tab.contains(block_num)) {
-                const block = self.tab.get(block_num).?;
-                return block[idx_offset];
-            }
-            self.mut.lock();
-            defer self.mut.unlock();
-            // Double check in case of race condition..
-            if (self.tab.contains(block_num)) {
-                const block = self.tab.get(block_num).?;
-                return block[idx_offset];
-            }
-            const is_last = (self.values - 1) / VALS_PER_BLOCK == block_num;
-            const slice_size = if (is_last) self.values - (block_num * VALS_PER_BLOCK) else VALS_PER_BLOCK;
-            const slice = try self.alloc.alloc(T, slice_size);
-            var rdr = try self.fil.readerAt(self.tab_start + (8 * block_num), &[0]u8{});
-            var offset: u64 = 0;
-            try rdr.interface.readSliceEndian(u64, @ptrCast(&offset), .little);
-            rdr = try self.fil.readerAt(offset, &[0]u8{});
-            var meta: MetadataReader = .init(self.alloc, &rdr.interface, self.decomp);
-            try meta.interface.readSliceEndian(T, @ptrCast(slice), .little);
-            try self.tab.put(block_num, slice);
-            return slice[idx_offset];
-        }
-    };
-}

src/test.zig

@@ -1,46 +1,51 @@
 const std = @import("std");
+const Io = std.Io;
+const io = std.testing.io;
+const alloc = std.testing.allocator;
 const stuff = @import("builtin");
 
 const Archive = @import("archive.zig");
-const Superblock = @import("super.zig").Superblock;
+const Superblock = Archive.Superblock;
 
 const TestArchive = "testing/LinuxPATest.sfs";
 
 test "Basics" {
-    var fil = try std.fs.cwd().openFile(TestArchive, .{});
-    defer fil.close();
-    var sfs: Archive = try .init(std.testing.allocator, fil);
-    defer sfs.deinit();
-    if (sfs.super != LinuxPATestCorrectSuperblock) {
-        std.debug.print("Superblock wrong\nShould be: {}\n\nis: {}\n", .{ LinuxPATestCorrectSuperblock, sfs.super });
-        return error.BadSuperblock;
-    }
+    std.debug.print("Starting test: Basics...\n", .{});
+
+    var fil = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer fil.close(io);
+    var sfs: Archive = try .init(io, fil, 0);
+    try std.testing.expectEqualDeep(sfs.super, LinuxPATestCorrectSuperblock);
+    const root_file = try sfs.root(alloc, io);
+    defer root_file.deinit();
 }
 
 const TestFile = "Start.exe";
 const TestFileExtractLocation = "testing/Start.exe";
 
 test "ExtractSingleFile" {
-    std.fs.cwd().deleteFile(TestFileExtractLocation) catch {};
-    var fil = try std.fs.cwd().openFile(TestArchive, .{});
-    defer fil.close();
-    var sfs: Archive = try .init(std.testing.allocator, fil);
-    defer sfs.deinit();
-    var test_fil = try sfs.open(TestFile);
+    std.debug.print("Starting test: ExtractSingleFile...\n", .{});
+
+    Io.Dir.cwd().deleteFile(io, TestFileExtractLocation) catch {};
+    var fil = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer fil.close(io);
+    var sfs: Archive = try .init(io, fil, 0);
+    var test_fil = try sfs.open(alloc, io, TestFile);
     defer test_fil.deinit();
-    try test_fil.extract(TestFileExtractLocation, .Default);
+    try test_fil.extract(alloc, io, TestFileExtractLocation, try .Default());
     //TODO: validate extracted file.
 }
 
 const TestFullExtractLocation = "testing/TestExtract";
 
 test "ExtractCompleteArchive" {
-    std.fs.cwd().deleteTree(TestFullExtractLocation) catch {};
-    var fil = try std.fs.cwd().openFile(TestArchive, .{});
-    defer fil.close();
-    var sfs: Archive = try .init(std.testing.allocator, fil);
-    defer sfs.deinit();
-    try sfs.extract(TestFullExtractLocation, .Default);
+    std.debug.print("Starting test: ExtractCompleteArchive...\n", .{});
+
+    Io.Dir.cwd().deleteTree(io, TestFullExtractLocation) catch {};
+    var fil = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer fil.close(io);
+    var sfs: Archive = try .init(io, fil, 0);
+    try sfs.extract(alloc, io, TestFullExtractLocation, try .Default());
 }
 
 const LinuxPATestCorrectSuperblock: Superblock = .{

src/util/data.zig

@@ -1,174 +0,0 @@
-//! A reader for a regular file.
-
-const std = @import("std");
-const Reader = std.Io.Reader;
-const Writer = std.Io.Writer;
-const Limit = std.Io.Limit;
-
-const Archive = @import("../archive.zig");
-const DecompFn = @import("../decomp.zig").DecompFn;
-const BlockSize = @import("../inode_data/file.zig").BlockSize;
-const FragEntry = @import("../tables.zig").FragEntry;
-const OffsetFile = @import("offset_file.zig");
-
-const DataReader = @This();
-
-alloc: std.mem.Allocator,
-fil: OffsetFile,
-decomp: DecompFn,
-block_size: u32,
-
-blocks: []BlockSize,
-
-frag: ?FragEntry = null, // TODO: do something better?
-frag_offset: u32 = 0,
-size: u64,
-
-interface: Reader,
-
-cur_offset: u64,
-block_idx: u32 = 0,
-
-pub fn init(alloc: std.mem.Allocator, archive: Archive, blocks: []BlockSize, start: u64, size: u64) DataReader {
-    return .{
-        .alloc = alloc,
-        .fil = archive.fil,
-        .decomp = archive.decomp,
-        .block_size = archive.super.block_size,
-        .blocks = blocks,
-        .size = size,
-        .cur_offset = start,
-        .interface = .{
-            .end = 0,
-            .seek = 0,
-            .buffer = &[0]u8{},
-            .vtable = &.{
-                .stream = stream,
-                .discard = discard,
-                .readVec = readVec,
-            },
-        },
-    };
-}
-pub fn deinit(self: *DataReader) void {
-    self.alloc.free(self.interface.buffer);
-    self.interface.end = 0;
-    self.interface.seek = 0;
-}
-
-pub fn addFragment(self: *DataReader, entry: FragEntry, frag_offset: u32) void {
-    self.frag = entry;
-    self.frag_offset = frag_offset;
-}
-
-fn numBlocks(self: DataReader) usize {
-    var res = self.blocks.len;
-    if (self.frag != null) res += 1;
-    return res;
-}
-
-fn advance(self: *DataReader) !void {
-    if (self.block_idx > self.blocks.len or (self.block_idx == self.blocks.len and self.frag == null)) {
-        if (self.interface.buffer.len > 0) {
-            self.alloc.free(self.interface.buffer);
-            self.interface.buffer = &[0]u8{};
-            self.interface.end = 0;
-            self.interface.seek = 0;
-        }
-        return Reader.Error.EndOfStream;
-    }
-    defer self.block_idx += 1;
-    const cur_block_size = if (self.block_idx == self.numBlocks() - 1) self.size % self.block_size else self.block_size;
-    try self.resizeBuffer(cur_block_size);
-    self.interface.seek = 0;
-    self.interface.end = cur_block_size;
-    if (self.block_idx == self.blocks.len) { // fragment
-        var rdr = try self.fil.readerAt(self.frag.?.start, &[0]u8{});
-        if (self.frag.?.size.uncompressed) {
-            try rdr.interface.discardAll(self.frag_offset);
-            try rdr.interface.readSliceAll(self.interface.buffer);
-            return;
-        }
-        const tmp_buf = try self.alloc.alloc(u8, self.frag.?.size.size);
-        defer self.alloc.free(tmp_buf);
-        try rdr.interface.readSliceAll(tmp_buf);
-        const needed_block = try self.alloc.alloc(u8, self.block_size);
-        defer self.alloc.free(needed_block);
-        _ = try self.decomp(self.alloc, tmp_buf, needed_block);
-        @memcpy(self.interface.buffer, needed_block[self.frag_offset .. self.frag_offset + cur_block_size]);
-        return;
-    }
-    const block = self.blocks[self.block_idx];
-    if (block.size == 0) {
-        @memset(self.interface.buffer, 0);
-        return;
-    }
-    var rdr = try self.fil.readerAt(self.cur_offset, &[0]u8{});
-    self.cur_offset += block.size;
-    if (block.uncompressed) {
-        try rdr.interface.readSliceAll(self.interface.buffer);
-        return;
-    }
-    const tmp_buf = try self.alloc.alloc(u8, block.size);
-    defer self.alloc.free(tmp_buf);
-    try rdr.interface.readSliceAll(tmp_buf);
-    _ = try self.decomp(self.alloc, tmp_buf, self.interface.buffer);
-}
-/// Does not guarentee that data currently in the buffer is retained.
-fn resizeBuffer(self: *DataReader, size: usize) !void {
-    if (self.interface.buffer.len == size) return;
-    if (!self.alloc.resize(self.interface.buffer, size)) {
-        self.alloc.free(self.interface.buffer);
-        self.interface.buffer = self.alloc.alloc(u8, size) catch |err| {
-            self.interface.buffer = &[0]u8{};
-            return err;
-        };
-    } else {
-        self.interface.buffer.len = size;
-    }
-}
-
-fn stream(rdr: *Reader, wrt: *Writer, limit: Limit) Reader.StreamError!usize {
-    var self: *DataReader = @alignCast(@fieldParentPtr("interface", rdr));
-    if (rdr.seek >= rdr.end) self.advance() catch |err| {
-        if (err == error.EndOfStream) return error.EndOfStream;
-        std.log.err("Error advancing data reader: {}\n", .{err});
-        return Reader.Error.ReadFailed;
-    };
-    if (limit == .nothing) return 0;
-    const to_read = @min(rdr.end - rdr.seek, @intFromEnum(limit));
-    const res = try wrt.write(rdr.buffer[rdr.seek .. rdr.seek + to_read]);
-    rdr.seek += res;
-    return res;
-}
-
-fn discard(rdr: *Reader, limit: Limit) Reader.Error!usize {
-    var self: *DataReader = @alignCast(@fieldParentPtr("interface", rdr));
-    if (rdr.seek >= rdr.end) self.advance() catch |err| {
-        if (err == error.EndOfStream) return error.EndOfStream;
-        std.log.err("Error advancing data reader: {}\n", .{err});
-        return Reader.Error.ReadFailed;
-    };
-    if (limit == .nothing) return 0;
-    const to_adv = @min(rdr.end - rdr.seek, @intFromEnum(limit));
-    rdr.seek += to_adv;
-    return to_adv;
-}
-
-fn readVec(rdr: *Reader, vec: [][]u8) Reader.Error!usize {
-    var self: *DataReader = @alignCast(@fieldParentPtr("interface", rdr));
-    if (rdr.seek >= rdr.end) self.advance() catch |err| {
-        if (err == error.EndOfStream) return error.EndOfStream;
-        std.log.err("Error advancing data reader: {}\n", .{err});
-        return Reader.Error.ReadFailed;
-    };
-    var cur_red: usize = 0;
-    for (vec) |s| {
-        const to_copy: usize = @min(rdr.end - rdr.seek, s.len);
-        @memcpy(s[0..to_copy], rdr.buffer[rdr.seek .. rdr.seek + to_copy]);
-        rdr.seek += to_copy;
-        cur_red += to_copy;
-        if (rdr.end == rdr.seek) break;
-    }
-    return cur_red;
-}

src/util/data_extractor.zig

@@ -0,0 +1,180 @@
+//! The DataExtractor is meant to extract a regular file's data to a given file asyncronously.
+
+const std = @import("std");
+const Io = std.Io;
+
+const FragEntry = @import("../frag.zig").FragEntry;
+const BlockSize = @import("../inode_data/file.zig").BlockSize;
+const Decompressor = @import("decompressor.zig");
+const OffsetFile = @import("offset_file.zig");
+
+// const SharedCache = @import("shared_cache.zig");
+
+pub const Error = error{OutOfMemory} || Io.File.Reader.SeekError || Io.Writer.Error;
+
+const DataExtractor = @This();
+
+fil: OffsetFile,
+decomp: *const Decompressor,
+block_size: u32,
+
+file_size: u64,
+start: u64,
+blocks: []BlockSize,
+
+frag_offset: u32 = 0,
+frag_entry: ?FragEntry = null,
+
+err: ?Error = null,
+
+pub fn init(fil: OffsetFile, decomp: *const Decompressor, block_size: u32, file_size: u64, data_start: u64, blocks: []BlockSize) DataExtractor {
+    return .{
+        .fil = fil,
+        .decomp = decomp,
+        .block_size = block_size,
+
+        .file_size = file_size,
+        .start = data_start,
+        .blocks = blocks,
+    };
+}
+pub fn addFrag(self: *DataExtractor, frag_offset: u32, entry: FragEntry) void {
+    self.frag_offset = frag_offset;
+    self.frag_entry = entry;
+}
+
+fn numBlocks(self: DataExtractor) usize {
+    var num = self.blocks.len;
+    if (self.frag_entry != null) num += 1;
+    return num;
+}
+
+/// Starts extracting the data using the given group to spawn async tasks.
+pub fn extractAsync(self: DataExtractor, alloc: std.mem.Allocator, io: Io, fil: Io.File) Error!void {
+    var group: Io.Group = .init;
+    defer group.cancel(io);
+    var err: ?Error = null;
+
+    var read_offset: u64 = self.start;
+    for (0..self.blocks.len) |idx| {
+        group.async(io, blockThread, .{ self, alloc, io, fil, read_offset, idx, &err });
+        read_offset += self.blocks[idx].size;
+    }
+    if (self.frag_entry != null)
+        group.async(io, fragThread, .{ self, alloc, io, fil, &err });
+
+    group.await(io) catch |cancel| return err orelse cancel;
+}
+
+fn blockThread(self: DataExtractor, alloc: std.mem.Allocator, io: Io, fil: Io.File, read_offset: u64, idx: usize, ret_err: *?Error) Io.Cancelable!void {
+    const block = self.blocks[idx];
+
+    const cur_block_size = if (idx == self.numBlocks() - 1)
+        self.file_size % self.block_size
+    else
+        self.block_size;
+
+    var wrt = fil.writer(io, &[0]u8{});
+    wrt.seekTo(self.block_size * idx) catch |err| {
+        ret_err.* = err;
+        if (err == error.Canceled) io.recancel();
+        return Io.Cancelable.Canceled;
+    };
+    defer wrt.flush() catch {};
+
+    if (block.size == 0) {
+        wrt.interface.splatByteAll(0, cur_block_size) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+        return;
+    }
+
+    var rdr = self.fil.readerAt(io, read_offset, &[0]u8{}) catch |err| {
+        ret_err.* = err;
+        if (err == error.Canceled) io.recancel();
+        return Io.Cancelable.Canceled;
+    };
+    if (block.uncompressed) {
+        rdr.interface.streamExact(&wrt.interface, cur_block_size) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+        return;
+    } else {
+        @branchHint(.likely);
+
+        var cache: [1024 * 1024]u8 = undefined;
+        var tmp: [1024 * 1024]u8 = undefined;
+
+        rdr.interface.readSliceAll(cache[0..block.size]) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+        _ = self.decomp.Decompress(alloc, cache[0..block.size], tmp[0..cur_block_size]) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+        wrt.interface.writeAll(tmp[0..cur_block_size]) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+    }
+}
+fn fragThread(self: DataExtractor, alloc: std.mem.Allocator, io: Io, fil: Io.File, ret_err: *?Error) Io.Cancelable!void {
+    const frag = self.frag_entry.?;
+    const cur_block_size = self.file_size % self.block_size;
+
+    var wrt = fil.writer(io, &[0]u8{});
+    wrt.seekTo(self.blocks.len * self.block_size) catch |err| {
+        ret_err.* = err;
+        if (err == error.Canceled) io.recancel();
+        return Io.Cancelable.Canceled;
+    };
+    defer wrt.flush() catch {};
+
+    var rdr = self.fil.readerAt(io, frag.start, &[0]u8{}) catch |err| {
+        ret_err.* = err;
+        if (err == error.Canceled) io.recancel();
+        return Io.Cancelable.Canceled;
+    };
+    if (frag.size.uncompressed) {
+        rdr.interface.discardAll(self.frag_offset) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+        rdr.interface.streamExact(&wrt.interface, cur_block_size) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+        return;
+    } else {
+        @branchHint(.likely);
+
+        var cache: [1024 * 1024]u8 = undefined;
+        var tmp: [1024 * 1024]u8 = undefined;
+
+        rdr.interface.readSliceAll(cache[0..frag.size.size]) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+        _ = self.decomp.Decompress(alloc, cache[0..frag.size.size], tmp[0..self.block_size]) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+        wrt.interface.writeAll(tmp[self.frag_offset .. self.frag_offset + cur_block_size]) catch |err| {
+            ret_err.* = err;
+            if (err == error.Canceled) io.recancel();
+            return Io.Cancelable.Canceled;
+        };
+    }
+}

src/util/data_reader.zig

@@ -0,0 +1,208 @@
+//! DataReader reads a regular file's data linearly from start to finish using Io.Reader interface.
+
+const std = @import("std");
+const Io = std.Io;
+const Reader = Io.Reader;
+const Writer = Io.Writer;
+const Limit = Io.Limit;
+
+const FragEntry = @import("../frag.zig").FragEntry;
+const BlockSize = @import("../inode_data/file.zig").BlockSize;
+const Decompressor = @import("decompressor.zig");
+const OffsetFile = @import("offset_file.zig");
+
+// const SharedCache = @import("shared_cache.zig");
+
+const DataReader = @This();
+
+alloc: std.mem.Allocator,
+
+fil: OffsetFile,
+io: Io,
+decomp: *const Decompressor,
+cache: *Io.Queue([]u8),
+block_size: u32,
+
+file_size: u64,
+cur_offset: u64,
+blocks: []BlockSize,
+
+frag_offset: u32 = 0,
+frag_entry: ?FragEntry = null,
+
+block_idx: usize = 0,
+sparse_block: bool = false,
+
+interface: Io.Reader,
+
+pub fn init(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, cache: *Io.Queue([]u8), block_size: u32, file_size: u64, data_start: u64, blocks: []BlockSize) !DataReader {
+    return .{
+        .alloc = alloc,
+
+        .fil = fil,
+        .io = io,
+        .decomp = decomp,
+        .cache = cache,
+        .block_size = block_size,
+
+        .file_size = file_size,
+        .cur_offset = data_start,
+        .blocks = blocks,
+
+        .interface = .{
+            .buffer = try alloc.alloc(u8, block_size),
+            .seek = 0,
+            .end = 0,
+            .vtable = &.{
+                .stream = stream,
+                .discard = discard,
+                .readVec = readVec,
+            },
+        },
+    };
+}
+pub fn deinit(self: *DataReader) void {
+    self.alloc.free(self.interface.buffer);
+}
+pub fn addFrag(self: *DataReader, frag_offset: u32, entry: FragEntry) void {
+    self.frag_offset = frag_offset;
+    self.frag_entry = entry;
+}
+
+fn numBlocks(self: DataReader) usize {
+    var num = self.blocks.len;
+    if (self.frag_entry != null) num += 1;
+    return num;
+}
+fn advanceBuffer(self: *DataReader) !void {
+    if (self.block_idx >= self.numBlocks()) {
+        return Reader.Error.EndOfStream;
+    }
+    defer self.block_idx += 1;
+
+    self.interface.end = if (self.block_idx == self.numBlocks() - 1)
+        self.size % self.block_size
+    else
+        self.block_size;
+
+    // Fragment
+    if (self.block_idx == self.blocks.len) {
+        const entry = self.frag_entry.?;
+        if (entry.size.uncompressed) {
+            var rdr = try self.fil.readerAt(self.io, entry.start + self.frag_offset, &[0]u8{});
+            try rdr.interface.readSliceAll(self.interface.buffer[0..self.interface.end]);
+        } else {
+            @branchHint(.likely);
+            const tmp = try self.cache.getOne(self.io);
+            defer self.cache.putOne(tmp) catch {};
+
+            var rdr = try self.fil.readerAt(self.io, entry.start, &[0]u8{});
+            try rdr.interface.readSliceAll(tmp.cache[0..entry.size.size]);
+            _ = try self.decomp.Decompress(self.alloc, tmp.cache[0..entry.size.size], self.interface.buffer[0..self.block_size]);
+            @memmove(self.interface.buffer[0..self.interface.end], self.interface.buffer[self.frag_offset .. self.frag_offset + self.interface.end]);
+        }
+        self.interface.seek = 0;
+        return;
+    }
+
+    // Normal Block
+    const block = self.blocks[self.block_idx];
+    if (block.size == 0) {
+        self.interface.seek = 0;
+        self.sparse_block = true;
+        return;
+    } else {
+        self.sparse_block = false;
+    }
+    if (block.uncompressed) {
+        try self.fil.readAt(self.io, self.cur_offset, self.interface.buffer[0..self.interface.end]);
+        self.cur_offset += self.interface.end;
+    } else {
+        @branchHint(.likely);
+        const tmp = try self.cache.getOne(self.io);
+        defer self.cache.putOne(tmp) catch {};
+
+        var rdr = try self.fil.readerAt(self.io, self.cur_offset, &[0]u8{});
+        try rdr.interface.readSliceAll(tmp.cache[0..block.size]);
+        self.cur_offset += block.size;
+        _ = try self.decomp.Decompress(self.alloc, tmp.cache[0..block.size], self.interface.buffer[0..self.interface.end]);
+    }
+    self.interface.seek = 0;
+}
+
+fn stream(rdr: *Reader, wrt: *Writer, limit: Limit) Reader.StreamError!usize {
+    var data: *DataReader = @fieldParentPtr("interface", rdr);
+    if (rdr.seek == rdr.end)
+        data.advanceBuffer() catch |err| return switch (err) {
+            error.ReadFailed => error.ReadFailed,
+            error.EndOfStream => error.EndOfStream,
+            else => error.ReadFailed,
+        };
+
+    switch (limit) {
+        .nothing => return 0,
+        .unlimited => {
+            const wrote = if (data.sparse_block)
+                try wrt.splatByte(0, rdr.end - rdr.seek)
+            else
+                try wrt.write(rdr.buffer[rdr.seek..rdr.end]);
+            rdr.seek += wrote;
+            return wrote;
+        },
+        else => {
+            const to_read = @min(rdr.end - rdr.seek, @intFromEnum(limit));
+            const wrote = if (data.sparse_block)
+                try wrt.splatByte(0, to_read)
+            else
+                try wrt.write(rdr.buffer[rdr.seek .. rdr.seek + to_read]);
+            rdr.seek += wrote;
+            return wrote;
+        },
+    }
+}
+fn discard(rdr: *Reader, limit: Limit) Reader.Error!usize {
+    var data: *DataReader = @fieldParentPtr("interface", rdr);
+    if (rdr.seek == rdr.end)
+        data.advanceBuffer() catch |err| return switch (err) {
+            error.ReadFailed => error.ReadFailed,
+            error.EndOfStream => error.EndOfStream,
+            else => error.ReadFailed,
+        };
+
+    switch (limit) {
+        .nothing => return 0,
+        .unlimited => {
+            const adv = rdr.end - rdr.seek;
+            rdr.seek = rdr.end;
+            return adv;
+        },
+        else => {
+            const adv = @min(rdr.end - rdr.seek, @intFromEnum(limit));
+            rdr.seek += adv;
+            return adv;
+        },
+    }
+}
+fn readVec(rdr: *Reader, vec: [][]u8) Reader.Error!usize {
+    var data: *DataReader = @fieldParentPtr("interface", rdr);
+    if (rdr.seek == rdr.end)
+        data.advanceBuffer() catch |err| return switch (err) {
+            error.ReadFailed => error.ReadFailed,
+            error.EndOfStream => error.EndOfStream,
+            else => error.ReadFailed,
+        };
+
+    var wrote: usize = 0;
+    for (vec) |buf| {
+        if (rdr.seek == rdr.end) break;
+
+        const to_copy = @min(rdr.end - rdr.seek, buf.len);
+        if (data.sparse_block)
+            @memset(buf[0..to_copy], 0)
+        else
+            @memcpy(buf[0..to_copy], rdr.buffer[rdr.seek .. rdr.seek + to_copy]);
+        rdr.seek += to_copy;
+        wrote += to_copy;
+    }
+    return wrote;
+}

src/util/data_threaded.zig

@@ -1,207 +0,0 @@
-//! Similiar to DataReader, but set-up for threaded writing to files.
-
-const std = @import("std");
-const Reader = std.Io.Reader;
-const Writer = std.Io.Writer;
-const Limit = std.Io.Limit;
-const WaitGroup = std.Thread.WaitGroup;
-const Pool = std.Thread.Pool;
-
-const Archive = @import("../archive.zig");
-const DecompFn = @import("../decomp.zig").DecompFn;
-const BlockSize = @import("../inode_data/file.zig").BlockSize;
-const FragEntry = @import("../tables.zig").FragEntry;
-const InodeFinish = @import("inode_finish.zig");
-const OffsetFile = @import("offset_file.zig");
-
-const ThreadedDataReader = @This();
-
-alloc: std.mem.Allocator,
-fil: OffsetFile,
-decomp: DecompFn,
-block_size: u32,
-
-blocks: []BlockSize,
-
-frag: ?FragEntry = null, // TODO: do something better?
-frag_offset: u32 = 0,
-size: u64,
-num_blocks: usize,
-
-start_offset: u64,
-
-pub fn init(alloc: std.mem.Allocator, archive: Archive, blocks: []BlockSize, start: u64, size: u64) ThreadedDataReader {
-    return .{
-        .alloc = alloc,
-        .fil = archive.fil,
-        .decomp = archive.decomp,
-        .block_size = archive.super.block_size,
-
-        .blocks = blocks,
-
-        .size = size,
-        .num_blocks = blocks.len,
-
-        .start_offset = start,
-    };
-}
-
-pub fn addFragment(self: *ThreadedDataReader, entry: FragEntry, frag_offset: u32) void {
-    self.frag = entry;
-    self.frag_offset = frag_offset;
-    self.num_blocks = self.blocks.len + 1;
-}
-
-/// Extract the data to the file threadedly, using pool to spawn threads.
-/// If errors occur, they are set to finish.out_err.
-pub fn extractThreaded(self: ThreadedDataReader, file: std.fs.File, pool: *Pool, finish: *InodeFinish) void {
-    var cur_write_offset: u64 = 0;
-    var cur_read_offset: u64 = self.start_offset;
-    for (0..self.blocks.len) |i| {
-        const cur_block_size = if (i == self.num_blocks - 1) self.size % self.block_size else self.block_size;
-        pool.spawn(workThreadBlocks, .{ self, file, cur_write_offset, cur_read_offset, self.blocks[i], cur_block_size, finish }) catch |res_err| {
-            finish.logError("Can't spawn pool task: {}", .{res_err});
-            finish.out_err.* = res_err;
-            finish.finish();
-        };
-        cur_write_offset += cur_block_size;
-        cur_read_offset += self.blocks[i].size;
-    }
-    if (self.frag != null)
-        pool.spawn(workThreadFragment, .{ self, file, cur_write_offset, finish }) catch |res_err| {
-            finish.logError("Can't spawn pool task: {}", .{res_err});
-            finish.out_err.* = res_err;
-            finish.finish();
-        };
-}
-
-fn workThreadBlocks(
-    self: ThreadedDataReader,
-    fil: std.fs.File,
-    write_offset: u64,
-    read_offset: u64,
-    block: BlockSize,
-    cur_block_size: u64,
-    finish: *InodeFinish,
-) void {
-    defer finish.finish();
-    var wrt = fil.writer(&[0]u8{});
-    wrt.seekTo(write_offset) catch |err| {
-        finish.logError("Error seeking file writer: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    defer wrt.interface.flush() catch |err| {
-        finish.logError("Error flushing file writer: {}", .{err});
-        finish.out_err.* = err;
-    };
-    if (block.size == 0) {
-        wrt.interface.splatByteAll(0, cur_block_size) catch |err| {
-            finish.logError("Error writing zeroes: {}", .{err});
-            finish.out_err.* = err;
-            return;
-        };
-        return;
-    }
-    var rdr = self.fil.readerAt(read_offset, &[0]u8{}) catch |err| {
-        finish.logError("Error creating file reader: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    if (block.uncompressed) {
-        rdr.interface.streamExact(&wrt.interface, block.size) catch |err| {
-            finish.logError("Error streaming data: {}", .{err});
-            finish.out_err.* = err;
-            return;
-        };
-        return;
-    }
-    // TODO: shared buffers
-    const read_buf = self.alloc.alloc(u8, block.size) catch |err| {
-        finish.logError("Error creating reader buffer: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    defer self.alloc.free(read_buf);
-    rdr.interface.readSliceAll(read_buf) catch |err| {
-        finish.logError("Error reading data into reader buffer: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    // TODO: shared buffers
-    const res_buf = self.alloc.alloc(u8, cur_block_size) catch |err| {
-        finish.logError("Error creating result buffer: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    defer self.alloc.free(res_buf);
-    _ = self.decomp(self.alloc, read_buf, res_buf) catch |err| {
-        finish.logError("Error decompressing data block: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    wrt.interface.writeAll(res_buf) catch |err| {
-        finish.logError("Error writing to file: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-}
-fn workThreadFragment(self: ThreadedDataReader, fil: std.fs.File, write_offset: u64, finish: *InodeFinish) void {
-    defer finish.finish();
-
-    var wrt = fil.writer(&[0]u8{});
-    wrt.seekTo(write_offset) catch |err| {
-        finish.logError("Error seeking file writer for file fragment: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    defer wrt.interface.flush() catch |err| {
-        finish.out_err.* = err;
-    };
-
-    var rdr = self.fil.readerAt(self.frag.?.start, &[0]u8{}) catch |err| {
-        finish.logError("Error creating file reader for file fragment: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    if (self.frag.?.size.uncompressed) {
-        rdr.interface.discardAll(self.frag_offset) catch |err| {
-            finish.logError("Error discarding useless fragment data: {}", .{err});
-            finish.out_err.* = err;
-            return;
-        };
-        rdr.interface.streamExact(&wrt.interface, self.size % self.block_size) catch |err| {
-            finish.logError("Error streaming fragment data: {}", .{err});
-            finish.out_err.* = err;
-            return;
-        };
-        return;
-    }
-    const tmp_buf = self.alloc.alloc(u8, self.frag.?.size.size) catch |err| {
-        finish.logError("Error creating a temporary buffer for a file fragment: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    defer self.alloc.free(tmp_buf);
-    rdr.interface.readSliceAll(tmp_buf) catch |err| {
-        finish.logError("Error reading data into fragment buffer: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    const needed_block = self.alloc.alloc(u8, self.block_size) catch |err| {
-        finish.logError("Error allocating fragment decompression results: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    defer self.alloc.free(needed_block);
-    _ = self.decomp(self.alloc, tmp_buf, needed_block) catch |err| {
-        finish.logError("Error decompressing fragment: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-    wrt.interface.writeAll(needed_block[self.frag_offset .. self.frag_offset + (self.size % self.block_size)]) catch |err| {
-        finish.logError("Error writing fragment: {}", .{err});
-        finish.out_err.* = err;
-        return;
-    };
-}

src/util/decompressor.zig

@@ -0,0 +1,15 @@
+//! A decompression interface
+
+const std = @import("std");
+
+const Decompressor = @This();
+
+pub const Error = std.Io.Reader.StreamError || std.mem.Allocator.Error;
+
+/// The actual decompression function.
+/// If the given decompressor is null, then the decompression should be done "stateless" without lasting allocations.
+decomp_fn: *const fn (?*const Decompressor, std.mem.Allocator, in: []u8, out: []u8) Error!usize,
+
+pub fn Decompress(self: *const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    return self.decomp_fn(self, alloc, in, out);
+}

src/util/extract.zig

@@ -1,353 +0,0 @@
-const std = @import("std");
-const Allocator = std.mem.Allocator;
-const Pool = std.Thread.Pool;
-const WaitGroup = std.Thread.WaitGroup;
-
-const Archive = @import("../archive.zig");
-const DirEntry = @import("../dir_entry.zig");
-const Inode = @import("../inode.zig");
-const ExtractionOptions = @import("../options.zig");
-const Tables = @import("../tables.zig");
-const InodeFinish = @import("inode_finish.zig");
-const FinishUnion = InodeFinish.FinishUnion;
-const ThreadedDataReader = @import("data_threaded.zig");
-
-// 1 MB
-const STACK_ALLOC_SIZE = 1024 * 1024;
-
-pub fn extractTo(
-    allocator: Allocator,
-    inode: Inode,
-    archive: Archive,
-    path: []const u8,
-    options: ExtractionOptions,
-) !void {
-    if (path[path.len - 1] == '/')
-        return extractTo(allocator, inode, archive, path[0 .. path.len - 2], options);
-
-    var stack_alloc = std.heap.stackFallback(STACK_ALLOC_SIZE, allocator);
-    var arena: std.heap.ArenaAllocator = .init(stack_alloc.get());
-    defer arena.deinit();
-    if (options.threads <= 1) {
-        const alloc = arena.allocator();
-        var tables: Tables = try .init(alloc, archive);
-        return extractSingleThread(arena.allocator(), inode, archive, &tables, path, options);
-    }
-
-    var thread_alloc = std.heap.ThreadSafeAllocator{ .child_allocator = arena.allocator() };
-    const alloc = thread_alloc.allocator();
-    var tables: Tables = try .init(alloc, archive);
-
-    var pool_alloc = std.heap.stackFallback(10 * 1024, alloc);
-    var pool: Pool = undefined;
-    try pool.init(.{ .allocator = pool_alloc.get(), .n_jobs = options.threads - 1 });
-
-    var wg: WaitGroup = .{};
-    var err: ?anyerror = null;
-    wg.start();
-    try pool.spawn(extractMultiThread, .{
-        alloc,
-        inode,
-        archive,
-        &tables,
-        path,
-        options,
-        &pool,
-        FinishUnion{ .wg = &wg },
-        &err,
-    });
-    pool.waitAndWork(&wg);
-    if (err != null) return err.?;
-}
-
-fn extractSingleThread(
-    alloc: Allocator,
-    inode: Inode,
-    archive: Archive,
-    tables: *Tables,
-    path: []const u8,
-    options: ExtractionOptions,
-) !void {
-    switch (inode.hdr.inode_type) {
-        .dir, .ext_dir => {
-            _ = std.fs.cwd().makeDir(path) catch |err| switch (err) {
-                std.fs.Dir.MakeError.PathAlreadyExists => {},
-                else => return err,
-            };
-
-            // Currently we are ignoring any deinit or free calls since we know we are under an ArenaAllocator.
-            // Possibly in the future, do some simple math to see if it would be safe to ONLY deinit via Arena,
-            // otherwise be more conscientious about freeing memory.
-            // For now, this is good enough.
-
-            const entries = try inode.dirEntries(alloc, archive);
-            for (entries) |ent| {
-                const sub_inode: Inode = try .readFromEntry(alloc, archive, ent);
-                const new_path = try std.mem.concat(alloc, u8, &[_][]const u8{ path, "/", ent.name });
-                try extractSingleThread(alloc, sub_inode, archive, tables, new_path, options);
-            }
-
-            const fil = try std.fs.cwd().openFile(path, .{});
-            defer fil.close();
-            try inode.setMetadata(alloc, tables, fil, options);
-        },
-        .file, .ext_file => {
-            var fil = try std.fs.cwd().createFile(path, .{ .exclusive = true });
-            defer fil.close();
-            var wrt = fil.writer(&[0]u8{});
-            var dat_rdr = try inode.dataReader(alloc, archive, tables);
-            defer dat_rdr.deinit();
-            _ = try dat_rdr.interface.streamRemaining(&wrt.interface);
-            try wrt.interface.flush();
-
-            try inode.setMetadata(alloc, tables, fil, options);
-        },
-        .symlink, .ext_symlink => return extractSymlink(inode, path),
-        else => return extractDeviceAndIPC(inode, alloc, tables, path, options),
-    }
-}
-
-fn extractMultiThread(
-    alloc: Allocator,
-    inode: Inode,
-    archive: Archive,
-    tables: *Tables,
-    path: []const u8,
-    options: ExtractionOptions,
-    pool: *Pool,
-    fin: FinishUnion,
-    err: *?anyerror,
-) void {
-    if (err.* != null) {
-        fin.finish();
-        return;
-    }
-    switch (inode.hdr.inode_type) {
-        .dir, .ext_dir => {
-            _ = std.fs.cwd().makeDir(path) catch |res_err| switch (res_err) {
-                std.fs.Dir.MakeError.PathAlreadyExists => {},
-                else => {
-                    err.* = res_err;
-                    fin.finish();
-                    return;
-                },
-            };
-
-            // Currently we are ignoring any deinit or free calls since we know we are under an ArenaAllocator.
-            // Possibly in the future, do some simple math to see if it would be safe to ONLY deinit via Arena,
-            // otherwise be more conscientious about freeing memory.
-            // For now, this is good enough.
-
-            const entries = inode.dirEntries(alloc, archive) catch |res_err| {
-                err.* = res_err;
-                fin.finish();
-                return;
-            };
-
-            if (entries.len == 0) {
-                fin.finish();
-                return;
-            }
-
-            var dir_fin = InodeFinish.create(
-                alloc,
-                inode,
-                path,
-                tables,
-                options,
-                fin,
-                err,
-                null,
-                entries.len,
-            ) catch |res_err| {
-                err.* = res_err;
-                fin.finish();
-                return;
-            };
-
-            for (entries) |ent| {
-                if (ent.inode_type == .dir) {
-                    extractEntry(
-                        alloc,
-                        ent,
-                        archive,
-                        tables,
-                        path,
-                        options,
-                        pool,
-                        .{ .fin = dir_fin },
-                        err,
-                    );
-                    continue;
-                }
-
-                pool.spawn(
-                    extractEntry,
-                    .{ alloc, ent, archive, tables, path, options, pool, FinishUnion{ .fin = dir_fin }, err },
-                ) catch |res_err| {
-                    err.* = res_err;
-                    dir_fin.finish();
-                    return;
-                };
-            }
-        },
-        .file, .ext_file => {
-            const fil = std.fs.cwd().createFile(path, .{ .exclusive = true }) catch |res_err| {
-                if (options.verbose)
-                    options.verbose_writer.?.print("Can't create file at {s}: {}\n", .{ path, res_err }) catch {};
-                err.* = res_err;
-                fin.finish();
-                return;
-            };
-
-            var data_rdr = threadedDataReader(inode, alloc, archive, tables) catch |res_err| {
-                if (options.verbose)
-                    options.verbose_writer.?.print("Can't create data reader for inode #{} (extracting to {s}): {}\n", .{ inode.hdr.num, path, res_err }) catch {};
-                err.* = res_err;
-                fin.finish();
-                return;
-            };
-            if (data_rdr == null) {
-                inode.setMetadata(alloc, tables, fil, options) catch |res_err| {
-                    if (options.verbose)
-                        options.verbose_writer.?.print("Can't set metadata to {s}: {}\n", .{ path, res_err }) catch {};
-                    err.* = res_err;
-                };
-                fin.finish();
-                return;
-            }
-            const file_fin = InodeFinish.create(
-                alloc,
-                inode,
-                path,
-                tables,
-                options,
-                fin,
-                err,
-                fil,
-                data_rdr.?.num_blocks,
-            ) catch |res_err| {
-                if (options.verbose)
-                    options.verbose_writer.?.print("Can't create callback for inode #{} (extracting to {s}): {}\n", .{ inode.hdr.num, path, res_err }) catch {};
-                err.* = res_err;
-                fin.finish();
-                return;
-            };
-
-            data_rdr.?.extractThreaded(fil, pool, file_fin);
-        },
-        .symlink, .ext_symlink => {
-            extractSymlink(inode, path) catch |res_err| {
-                err.* = res_err;
-            };
-            fin.finish();
-        },
-        else => {
-            extractDeviceAndIPC(inode, alloc, tables, path, options) catch |res_err| {
-                err.* = res_err;
-            };
-            fin.finish();
-        },
-    }
-}
-
-fn extractEntry(
-    alloc: Allocator,
-    ent: DirEntry,
-    archive: Archive,
-    tables: *Tables,
-    path: []const u8,
-    options: ExtractionOptions,
-    pool: *Pool,
-    fin: FinishUnion,
-    err: *?anyerror,
-) void {
-    const new_path = std.mem.concat(alloc, u8, &[_][]const u8{ path, "/", ent.name }) catch |res_err| {
-        err.* = res_err;
-        fin.finish();
-        return;
-    };
-
-    const inode = Inode.readFromEntry(alloc, archive, ent) catch |res_err| {
-        err.* = res_err;
-        fin.finish();
-        return;
-    };
-    extractMultiThread(alloc, inode, archive, tables, new_path, options, pool, fin, err);
-}
-
-/// Get a threaded data reader for a file inode.
-fn threadedDataReader(self: Inode, alloc: std.mem.Allocator, archive: Archive, tables: *Tables) !?ThreadedDataReader {
-    return switch (self.hdr.inode_type) {
-        .file => threadedReaderFromData(alloc, archive, tables, self.data.file),
-        .ext_file => threadedReaderFromData(alloc, archive, tables, self.data.ext_file),
-        else => error.NotRegularFile,
-    };
-}
-fn threadedReaderFromData(alloc: std.mem.Allocator, archive: Archive, tables: *Tables, data: anytype) !?ThreadedDataReader {
-    if (data.block_sizes.len == 0 and data.frag_idx == 0xFFFFFFFF) return null;
-    var out: ThreadedDataReader = .init(alloc, archive, data.block_sizes, data.block_start, data.size);
-    if (data.frag_idx != 0xFFFFFFFF)
-        out.addFragment(try tables.frag_table.get(data.frag_idx), data.frag_block_offset);
-    return out;
-}
-
-/// Creates the symlink described by the inode.
-/// Sets metadata.
-fn extractSymlink(self: Inode, path: []const u8) !void {
-    const target = switch (self.data) {
-        .symlink => |s| s.target,
-        .ext_symlink => |s| s.target,
-        else => unreachable,
-    };
-    try std.fs.cwd().symLink(target, path, .{});
-}
-/// Creates the device described by the inode.
-/// Sets metadata.
-fn extractDeviceAndIPC(self: Inode, alloc: std.mem.Allocator, tables: *Tables, path: []const u8, options: ExtractionOptions) !void {
-    var mode: u32 = undefined;
-    var dev: u32 = 0;
-    switch (self.data) {
-        .char_dev => |d| {
-            mode = std.posix.S.IFCHR;
-            dev = d.dev;
-        },
-        .ext_char_dev => |d| {
-            mode = std.posix.S.IFCHR;
-            dev = d.dev;
-        },
-        .block_dev => |d| {
-            mode = std.posix.S.IFBLK;
-            dev = d.dev;
-        },
-        .ext_block_dev => |d| {
-            mode = std.posix.S.IFBLK;
-            dev = d.dev;
-        },
-        .fifo, .ext_fifo => mode = std.posix.S.IFIFO,
-        .socket, .ext_socket => mode = std.posix.S.IFSOCK,
-        else => unreachable,
-    }
-    const res: std.os.linux.E = @enumFromInt(std.os.linux.mknod(@ptrCast(path), mode, dev));
-    switch (res) {
-        .SUCCESS => {},
-        .ACCES => return std.fs.Dir.MakeError.AccessDenied,
-        .DQUOT => return std.fs.Dir.MakeError.DiskQuota,
-        .EXIST => return std.fs.Dir.MakeError.PathAlreadyExists,
-        .FAULT, .NOENT => return std.fs.Dir.MakeError.BadPathName,
-        .LOOP => return std.fs.Dir.MakeError.SymLinkLoop,
-        .NAMETOOLONG => return std.fs.Dir.MakeError.NameTooLong,
-        .NOMEM => return std.fs.Dir.MakeError.SystemResources,
-        .NOSPC => return std.fs.Dir.MakeError.NoSpaceLeft,
-        .NOTDIR => return std.fs.Dir.MakeError.NotDir,
-        .PERM => return std.fs.Dir.MakeError.PermissionDenied,
-        .ROFS => return std.fs.Dir.MakeError.ReadOnlyFileSystem,
-        else => return blk: {
-            std.debug.print("unhandled mknod result: {}\n", .{res});
-            break :blk std.fs.Dir.MakeError.Unexpected;
-        },
-    }
-    var fil = try std.fs.cwd().openFile(path, .{});
-    defer fil.close();
-    try self.setMetadata(alloc, tables, fil, options);
-}

src/util/inode_finish.zig

@@ -1,101 +0,0 @@
-const std = @import("std");
-const WaitGroup = std.Thread.WaitGroup;
-const Mutex = std.Thread.Mutex;
-
-const Archive = @import("../archive.zig");
-const Inode = @import("../inode.zig");
-const ExtractionOptions = @import("../options.zig");
-const Tables = @import("../tables.zig");
-
-const InodeFinish = @This();
-
-const FinishEnum = enum {
-    wg,
-    fin,
-};
-pub const FinishUnion = union(FinishEnum) {
-    wg: *WaitGroup,
-    fin: *InodeFinish,
-
-    pub fn finish(self: FinishUnion) void {
-        switch (self) {
-            .wg => |wg| wg.finish(),
-            .fin => |fin| fin.finish(),
-        }
-    }
-};
-
-alloc: std.mem.Allocator,
-
-inode: Inode,
-path: []const u8,
-tables: *Tables,
-options: ExtractionOptions,
-parent_finish: FinishUnion,
-fil: ?std.fs.File,
-out_err: *?anyerror,
-
-wg: WaitGroup = .{},
-mut: Mutex = .{},
-
-pub fn create(
-    alloc: std.mem.Allocator,
-    inode: Inode,
-    path: []const u8,
-    tables: *Tables,
-    options: ExtractionOptions,
-    parent_finish: FinishUnion,
-    out_err: *?anyerror,
-    fil: ?std.fs.File,
-    work_size: usize,
-) !*InodeFinish {
-    if (work_size == 0)
-        return error.InvalidWorkSize;
-    const out = try alloc.create(InodeFinish);
-    errdefer alloc.destroy(out);
-    out.* = .{
-        .alloc = alloc,
-
-        .inode = inode,
-        .path = path,
-        .tables = tables,
-        .options = options,
-        .parent_finish = parent_finish,
-        .out_err = out_err,
-        .fil = fil,
-    };
-    out.wg.startMany(work_size);
-    return out;
-}
-
-pub fn logError(self: *InodeFinish, comptime fmt: []const u8, args: anytype) void {
-    if (self.options.verbose)
-        self.options.verbose_writer.?.print(fmt, args) catch {};
-}
-
-pub fn finish(self: *InodeFinish) void {
-    self.mut.lock();
-    {
-        defer self.mut.unlock();
-        self.wg.finish();
-        if (!self.wg.isDone()) return;
-    }
-    defer {
-        self.parent_finish.finish();
-        self.alloc.destroy(self);
-    }
-    if (self.fil == null)
-        self.fil = std.fs.cwd().openFile(self.path, .{}) catch |err| {
-            if (self.options.verbose)
-                self.options.verbose_writer.?.print("Error opening {s} to set metadata: {}\n", .{ self.path, err }) catch {};
-            self.out_err.* = err;
-            return;
-        };
-    defer self.fil.?.close();
-    self.inode.setMetadata(self.alloc, self.tables, self.fil.?, self.options) catch |err| {
-        if (self.options.verbose)
-            self.options.verbose_writer.?.print("Error setting metadata to {s}: {}\n", .{ self.path, err }) catch {};
-        self.out_err.* = err;
-        return;
-    };
-}

src/util/meta_cache.zig

@@ -1,41 +0,0 @@
-const std = @import("std");
-
-const OffsetFile = @import("offset_file.zig");
-
-const MetadataCache = @This();
-
-alloc: std.mem.Allocator,
-
-buf: []u8,
-fixed_alloc: std.heap.FixedBufferAllocator,
-
-cache: std.AutoArrayHashMap(u64, [8192]u8),
-
-mut: std.Thread.Mutex = .{},
-cache_mut: std.AutoArrayHashMap(u64, std.Thread.Mutex),
-
-fil: OffsetFile,
-
-pub fn init(alloc: std.mem.Allocator, cache_size: u64) !MetadataCache {}
-pub fn deinit(self: *MetadataCache) void {
-    self.mut.lock();
-    defer self.mut.unlock();
-    self.cache.deinit();
-    self.cache_mut.deinit();
-    self.alloc.free(self.buf);
-}
-
-pub fn getChunk(self: *MetadataCache, offset: u64) ![8192]u8 {
-    var res = self.cache.get(offset);
-    if (res != null) return res.?;
-    var offset_mut = blk: {
-        self.mut.lock();
-        defer self.mut.unlock();
-        const mut = try self.cache_mut.getOrPut(offset);
-        if (!mut.found_existing)
-            mut.value_ptr.* = .{};
-        break :blk mut.value_ptr;
-    };
-    offset_mut.lock();
-    defer offset_mut.unlock();
-}

src/util/metadata.zig

@@ -4,9 +4,9 @@ const Writer = std.Io.Writer;
 const Limit = std.Io.Limit;
 const StreamError = std.Io.Reader.StreamError;
 
-const DecompFn = @import("../decomp.zig").DecompFn;
+const Decompressor = @import("decompressor.zig");
 
-const BlockHeader = packed struct {
+const BlockHeader = packed struct(u16) {
     size: u15,
     uncompressed: bool,
 };
@@ -15,28 +15,30 @@ const This = @This();
 
 alloc: std.mem.Allocator,
 rdr: *Reader,
-decomp: DecompFn,
+decomp: *const Decompressor,
 
+cur_block_start: u32 = 0,
+next_start_start: u32 = 0,
 buf: [8192]u8 = undefined,
 
-interface: Reader,
 err: ?anyerror = null,
+interface: Reader = .{
+    .buffer = &[0]u8{},
+    .end = 0,
+    .seek = 0,
+    .vtable = &.{
+        .stream = stream,
+        .discard = discard,
+        .readVec = readVec,
+        // TODO: Potentially add rebase so that we can guarentee that self.block_start & interface.seek is correct.
+    },
+},
 
-pub fn init(alloc: std.mem.Allocator, rdr: *Reader, decomp: DecompFn) This {
+pub fn init(alloc: std.mem.Allocator, rdr: *Reader, decomp: *const Decompressor) This {
     return .{
         .alloc = alloc,
         .rdr = rdr,
         .decomp = decomp,
-        .interface = .{
-            .buffer = &[0]u8{},
-            .end = 0,
-            .seek = 0,
-            .vtable = &.{
-                .stream = stream,
-                .discard = discard,
-                .readVec = readVec,
-            },
-        },
     };
 }
 
@@ -44,16 +46,20 @@ fn advance(self: *This) !void {
     self.interface.seek = 0;
     var hdr: BlockHeader = undefined;
     try self.rdr.readSliceEndian(BlockHeader, @ptrCast(&hdr), .little);
+    self.cur_block_start = self.next_start_start;
+    self.next_start_start += hdr.size;
     if (hdr.uncompressed) {
         try self.rdr.readSliceEndian(u8, self.buf[0..hdr.size], .little);
         self.interface.end = hdr.size;
         self.interface.buffer = self.buf[0..hdr.size];
         return;
+    } else {
+        @branchHint(.likely);
+        var tmp_buf: [8192]u8 = undefined;
+        try self.rdr.readSliceAll(tmp_buf[0..hdr.size]);
+        self.interface.end = try self.decomp.Decompress(self.alloc, tmp_buf[0..hdr.size], &self.buf);
+        self.interface.buffer = self.buf[0..self.interface.end];
     }
-    var tmp_buf: [8192]u8 = undefined;
-    try self.rdr.readSliceAll(tmp_buf[0..hdr.size]);
-    self.interface.end = try self.decomp(self.alloc, tmp_buf[0..hdr.size], &self.buf);
-    self.interface.buffer = self.buf[0..self.interface.end];
 }
 
 fn stream(rdr: *Reader, wrt: *Writer, limit: Limit) StreamError!usize {
@@ -68,22 +74,22 @@ fn stream(rdr: *Reader, wrt: *Writer, limit: Limit) StreamError!usize {
     self.interface.seek += wrote;
     return wrote;
 }
-fn discard(rdr: *Reader, limit: Limit) error{ EndOfStream, ReadFailed }!usize {
+fn discard(rdr: *Reader, limit: Limit) Reader.Error!usize {
     const self: *This = @fieldParentPtr("interface", rdr);
     if (rdr.end == rdr.seek) self.advance() catch |err| {
         self.err = err;
-        return StreamError.ReadFailed;
+        return error.ReadFailed;
     };
     if (@intFromEnum(limit) == 0) return 0;
     const to_skip = @min(rdr.end - rdr.seek, @intFromEnum(limit));
     rdr.seek += to_skip;
     return to_skip;
 }
-fn readVec(rdr: *Reader, vec: [][]u8) error{ EndOfStream, ReadFailed }!usize {
+fn readVec(rdr: *Reader, vec: [][]u8) Reader.Error!usize {
     const self: *This = @fieldParentPtr("interface", rdr);
     if (rdr.end == rdr.seek) self.advance() catch |err| {
         self.err = err;
-        return StreamError.ReadFailed;
+        return error.ReadFailed;
     };
     var cur_red: usize = 0;
     for (vec) |s| {

src/util/misc.zig

@@ -0,0 +1,25 @@
+//! Miscellaneous utility functions.
+
+const std = @import("std");
+const Io = std.Io;
+
+const Inode = @import("../inode.zig");
+const Decompressor = @import("decompressor.zig");
+const MetadataReader = @import("metadata.zig");
+const OffsetFile = @import("offset_file.zig");
+
+/// check is the path is referencing itself ("" or ".").
+/// separators must be trimmed before calling this function for it to work properly.
+pub fn pathIsSelf(path: []const u8) bool {
+    if (path.len == 0) return true;
+    if (path.len > 1) return false;
+    return path[0] == '.';
+}
+/// Creates an Inode from an Inode.Ref.
+pub fn inodeFromRef(alloc: std.mem.Allocator, io: Io, file: OffsetFile, decomp: *const Decompressor, inode_start: u64, block_size: u32, ref: Inode.Ref) !Inode {
+    var rdr = try file.readerAt(io, inode_start + ref.block_start, &[0]u8{});
+    var meta: MetadataReader = .init(alloc, &rdr.interface, decomp);
+    try meta.interface.discardAll(ref.block_offset);
+
+    return .read(alloc, &meta.interface, block_size);
+}

src/util/offset_file.zig

@@ -1,8 +1,9 @@
 //! A File where it's meaningful (to us) content starts at a given offset.
 
 const std = @import("std");
-const File = std.fs.File;
-const Reader = std.fs.File.Reader;
+const Io = std.Io;
+const File = Io.File;
+const Reader = File.Reader;
 
 const OffsetFile = @This();
 
@@ -13,8 +14,11 @@ pub fn init(fil: File, init_offset: u64) OffsetFile {
     return .{ .fil = fil, .offset = init_offset };
 }
 
-pub fn readerAt(self: OffsetFile, offset: u64, buffer: []u8) !Reader {
-    var rdr = self.fil.reader(buffer);
+pub fn readerAt(self: OffsetFile, io: Io, offset: u64, buffer: []u8) Reader.SeekError!Reader {
+    var rdr = self.fil.reader(io, buffer);
     try rdr.seekTo(self.offset + offset);
     return rdr;
 }
+pub fn readAt(self: OffsetFile, io: Io, offset: u64, buf: []u8) File.ReadPositionalError!void {
+    _ = try self.fil.readPositionalAll(io, buf, self.offset + offset);
+}

src/util/shared_cache.zig

@@ -0,0 +1,52 @@
+const std = @import("std");
+const Io = std.Io;
+const Node = std.SinglyLinkedList.Node;
+
+const SharedCache = @This();
+
+pub const CACHE_SIZE = 1024 * 1024;
+
+pub const BufferNode = struct {
+    node: Node,
+    cache: [CACHE_SIZE]u8,
+};
+
+alloc: std.mem.Allocator,
+
+caches: std.ArrayList(BufferNode),
+cache_queue: std.SinglyLinkedList,
+queue_mut: Io.Mutex,
+
+pub fn init(alloc: std.mem.Allocator, init_cache_size: u32) !SharedCache {
+    const caches: std.ArrayList(BufferNode) = try .initCapacity(alloc, init_cache_size);
+    var queue: std.SinglyLinkedList = .{};
+    for (caches.items) |item|
+        queue.prepend(&item.node);
+    return .{
+        .alloc = alloc,
+
+        .caches = caches,
+        .cache_queue = queue,
+    };
+}
+pub fn deinit(self: *SharedCache) void {
+    self.caches.deinit(self.alloc);
+}
+
+pub fn getCache(self: *SharedCache, io: Io) !*BufferNode {
+    self.queue_mut.lock(io);
+    const nxt = self.cache_queue.popFirst();
+    self.queue_mut.unlock(io);
+    if (nxt == null) {
+        const new = try self.caches.addOne(self.alloc);
+        new.* = .{
+            .node = .{},
+            .cache = undefined,
+        };
+        return new;
+    }
+    return @fieldParentPtr("node", nxt.?);
+}
+pub fn returnCache(self: *SharedCache, buf: *BufferNode) void {
+    self.cache_queue.prepend(buf);
+}

src/xattr.zig

@@ -1,117 +0,0 @@
-const std = @import("std");
-
-const DecompFn = @import("decomp.zig").DecompFn;
-const Table = @import("tables.zig").Table;
-const MetadataReader = @import("util/metadata.zig");
-const OffsetFile = @import("util/offset_file.zig");
-
-const Ref = packed struct {
-    block_offset: u16,
-    block_start: u32,
-    _: u16,
-};
-const Entry = packed struct {
-    ref: Ref,
-    count: u32,
-    size: u32,
-};
-const KeyPrefix = enum(u8) {
-    user,
-    trusted,
-    security,
-};
-const KeyRaw = packed struct {
-    type: packed struct {
-        prefix: KeyPrefix,
-        out_of_line: bool,
-        _: u7,
-    },
-    name_size: u16,
-};
-
-pub const KeyValue = struct {
-    key: [:0]u8,
-    value: []u8,
-};
-
-const XattrTable = @This();
-
-alloc: std.mem.Allocator,
-fil: OffsetFile,
-decomp: DecompFn,
-
-count: u32,
-start: u64,
-
-table: Table(Entry),
-
-pub fn init(alloc: std.mem.Allocator, fil: OffsetFile, decomp: DecompFn, table_start: u64) !XattrTable {
-    var info = packed struct {
-        start: u64 = undefined,
-        count: u32 = undefined,
-        _: u32 = undefined,
-    }{};
-    var rdr = try fil.readerAt(table_start, &[0]u8{});
-    try rdr.interface.readSliceEndian(@TypeOf(info), @ptrCast(&info), .little);
-    return .{
-        .alloc = alloc,
-        .fil = fil,
-        .decomp = decomp,
-        .count = info.count,
-        .start = info.start,
-        .table = try .init(alloc, fil, decomp, table_start + 16, info.count),
-    };
-}
-pub fn deinit(self: *XattrTable) void {
-    self.table.deinit();
-}
-
-pub fn get(self: *XattrTable, alloc: std.mem.Allocator, idx: u32) ![]KeyValue {
-    const entry: Entry = try self.table.get(idx);
-    const out = try alloc.alloc(KeyValue, entry.count);
-
-    for (out) |*kv| {
-        var rdr = try self.fil.readerAt(self.start + entry.ref.block_start, &[0]u8{});
-        var meta: MetadataReader = .init(alloc, &rdr.interface, self.decomp);
-        try meta.interface.discardAll(entry.ref.block_offset);
-
-        var key_raw: KeyRaw = undefined;
-        try meta.interface.readSliceEndian(KeyRaw, @ptrCast(&key_raw), .little);
-
-        switch (key_raw.type.prefix) {
-            .user => {
-                kv.key = @ptrCast(try alloc.alloc(u8, key_raw.name_size + 5 + 1));
-                @memcpy(kv.key[0..5], "user.");
-                try meta.interface.readSliceAll(kv.key[5 .. kv.key.len - 1]);
-                kv.key[kv.key.len - 1] = 0;
-            },
-            .security => {
-                kv.key = @ptrCast(try alloc.alloc(u8, key_raw.name_size + 9 + 1));
-                @memcpy(kv.key[0..9], "security.");
-                try meta.interface.readSliceAll(kv.key[9 .. kv.key.len - 1]);
-                kv.key[kv.key.len - 1] = 0;
-            },
-            .trusted => {
-                kv.key = @ptrCast(try alloc.alloc(u8, key_raw.name_size + 8 + 1));
-                @memcpy(kv.key[0..8], "trusted.");
-                try meta.interface.readSliceAll(kv.key[8 .. kv.key.len - 1]);
-                kv.key[kv.key.len - 1] = 0;
-            },
-        }
-        if (key_raw.type.out_of_line) {
-            try meta.interface.discardAll(4);
-            var ref: Ref = undefined;
-            try meta.interface.readSliceEndian(Ref, @ptrCast(&ref), .little);
-
-            rdr = try self.fil.readerAt(self.start + ref.block_start, &[0]u8{});
-            meta = .init(alloc, &rdr.interface, self.decomp);
-            try meta.interface.discardAll(ref.block_offset);
-        }
-        var value_size: u32 = undefined;
-        try meta.interface.readSliceEndian(u32, @ptrCast(&value_size), .little);
-        kv.value = try alloc.alloc(u8, value_size);
-        try meta.interface.readSliceAll(kv.value);
-    }
-
-    return out;
-}

src/xattr_table.zig

@@ -0,0 +1,286 @@
+const std = @import("std");
+const Io = std.Io;
+
+const InodeRef = @import("inode.zig").Ref;
+const LookupTable = @import("lookup_table.zig");
+const Decompressor = @import("util/decompressor.zig");
+const MetadataReader = @import("util/metadata.zig");
+const OffsetFile = @import("util/offset_file.zig");
+
+const XattrCachedTable = @This();
+
+alloc: std.mem.Allocator,
+
+fil: OffsetFile,
+decomp: *const Decompressor,
+
+kv_start: u64,
+
+table: LookupTable.CachedTable(TableValue),
+value_cache: std.AutoHashMap(InodeRef, []const u8),
+value_mut: Io.Mutex = .init,
+
+pub fn init(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, xattr_start: u64) !XattrCachedTable {
+    var rdr = try fil.readerAt(io, xattr_start, &[0]u8{});
+
+    var start: u64 = undefined;
+    try rdr.interface.readSliceEndian(u64, @ptrCast(&start), .little);
+    var num: u32 = undefined;
+    try rdr.interface.readSliceEndian(u32, @ptrCast(&num), .little);
+
+    return .{
+        .alloc = alloc,
+
+        .fil = fil,
+        .decomp = decomp,
+
+        .kv_start = start,
+
+        .table = .init(alloc, fil, decomp, xattr_start + 16, num),
+        .value_cache = .init(alloc),
+    };
+}
+pub fn deinit(self: *XattrCachedTable, io: Io) void {
+    self.table.deinit(io);
+    self.value_cache.deinit();
+}
+
+pub fn get(self: *XattrCachedTable, alloc: std.mem.Allocator, io: Io, idx: u32) ![]XattrSemiOwned {
+    const lookup = try self.table.get(io, idx);
+
+    var rdr = try self.fil.readerAt(io, self.kv_start + lookup.ref.block_start, &[0]u8{});
+    var meta: MetadataReader = .init(alloc, &rdr.interface, self.decomp);
+    try meta.interface.discardAll(lookup.ref.block_offset);
+
+    const out = try alloc.alloc(XattrSemiOwned, lookup.count);
+    errdefer alloc.free(out);
+
+    for (0..lookup.count) |i| {
+        var key_entry: KeyEntry = undefined;
+        try meta.interface.readSliceEndian(KeyEntry, @ptrCast(&key_entry), .little);
+
+        const key: [:0]u8 = switch (key_entry.type.namespace) {
+            .user => blk: {
+                const tmp = try alloc.alloc(u8, key_entry.name_size + 1 + 5);
+                errdefer alloc.free(tmp);
+                try meta.interface.readSliceEndian(u8, tmp[5 .. tmp.len - 1], .little);
+                @memcpy(tmp[0..5], "user.");
+                tmp[tmp.len - 1] = 0;
+                break :blk @ptrCast(tmp);
+            },
+            .trusted => blk: {
+                const tmp = try alloc.alloc(u8, key_entry.name_size + 1 + 8);
+                errdefer alloc.free(tmp);
+                try meta.interface.readSliceEndian(u8, tmp[8 .. tmp.len - 1], .little);
+                @memcpy(tmp[0..8], "trusted.");
+                tmp[tmp.len - 1] = 0;
+                break :blk @ptrCast(tmp);
+            },
+            .security => blk: {
+                const tmp = try alloc.alloc(u8, key_entry.name_size + 1 + 9);
+                errdefer alloc.free(tmp);
+                try meta.interface.readSliceEndian(u8, tmp[9 .. tmp.len - 1], .little);
+                @memcpy(tmp[0..9], "security.");
+                tmp[tmp.len - 1] = 0;
+                break :blk @ptrCast(tmp);
+            },
+        };
+        errdefer alloc.free(key);
+
+        if (key_entry.type.out_of_line) {
+            var value: ValueOutOfLineEntry = undefined;
+            try meta.interface.readSliceEndian(ValueOutOfLineEntry, @ptrCast(&value), .little);
+
+            out[i] = .{
+                .key = key,
+                .value = try self.valueAt(io, value.ref),
+            };
+            continue;
+        }
+        const val_ref: InodeRef = .{ .block_start = meta.cur_block_start, .block_offset = @truncate(meta.interface.seek) };
+
+        try self.value_mut.lock(io);
+        defer self.value_mut.unlock(io);
+        if (self.value_cache.contains(val_ref)) {
+            out[i] = .{
+                .key = key,
+                .value = try self.valueAt(io, val_ref),
+            };
+            continue;
+        }
+
+        var val_size: u32 = undefined;
+        try meta.interface.readSliceEndian(u32, @ptrCast(&val_size), .little);
+
+        const val = try self.alloc.alloc(u8, val_size);
+        errdefer alloc.free(val);
+        try meta.interface.readSliceEndian(u8, val, .little);
+
+        try self.value_cache.put(val_ref, val);
+        out[i] = .{
+            .key = key,
+            .value = val,
+        };
+    }
+    return out;
+}
+
+fn valueAt(self: *XattrCachedTable, io: Io, ref: InodeRef) ![]const u8 {
+    try self.value_mut.lock(io);
+    defer self.value_mut.unlock(io);
+
+    if (self.value_cache.contains(ref)) return self.value_cache.get(ref).?;
+
+    var rdr = try self.fil.readerAt(io, self.kv_start + ref.block_start, &[0]u8{});
+    var meta: MetadataReader = .init(self.alloc, &rdr.interface, self.decomp);
+    try meta.interface.discardAll(ref.block_offset);
+
+    var val_size: u32 = undefined;
+    try meta.interface.readSliceEndian(u32, @ptrCast(&val_size), .little);
+
+    const val = try self.alloc.alloc(u8, val_size);
+    errdefer self.alloc.free(val);
+    try meta.interface.readSliceEndian(u8, val, .little);
+
+    try self.value_cache.put(ref, val);
+    return val;
+}
+
+// Types
+
+/// An Xattr return value where the reciever only owns the key value.
+pub const XattrSemiOwned = struct {
+    key: [:0]const u8,
+    value: []const u8,
+
+    pub fn deinit(self: XattrSemiOwned, alloc: std.mem.Allocator) void {
+        alloc.free(self.key);
+    }
+};
+/// An Xattr return value where the reciever owns both the key & value.
+pub const XattrOwned = struct {
+    key: [:0]const u8,
+    value: []const u8,
+
+    pub fn deinit(self: XattrSemiOwned, alloc: std.mem.Allocator) void {
+        alloc.free(self.key);
+        alloc.free(self.value);
+    }
+};
+
+const TableValue = extern struct {
+    ref: InodeRef,
+    count: u32,
+    size: u32,
+};
+
+const KeyEntry = extern struct {
+    type: XattrPrefix,
+    name_size: u16,
+};
+const ValueOutOfLineEntry = extern struct {
+    _: u32,
+    ref: InodeRef,
+};
+
+const XattrPrefix = packed struct(u16) {
+    namespace: enum(u8) {
+        user,
+        trusted,
+        security,
+
+        fn prefixSize(self: @This()) u16 {
+            return switch (self) {
+                .user => 5,
+                .trusted => 8,
+                .security => 9,
+            };
+        }
+    },
+    out_of_line: bool,
+    _: u7,
+};
+
+// Stateless
+
+pub fn statelessLookup(alloc: std.mem.Allocator, io: Io, decomp: *const Decompressor, fil: OffsetFile, table_start: u64, idx: u16) ![]XattrOwned {
+    var rdr = try fil.readerAt(io, table_start, &[0]u8{});
+
+    var kv_start: u64 = undefined;
+    try rdr.interface.readSliceEndian(u64, @ptrCast(&kv_start), .little);
+
+    const lookup = try LookupTable.lookupValue(TableValue, alloc, io, decomp, fil, table_start + 16, idx);
+
+    rdr = try fil.readerAt(io, kv_start + lookup.ref.block_start, &[0]u8{});
+    var meta: MetadataReader = .init(alloc, &rdr.interface, decomp);
+    try meta.interface.discardAll(lookup.ref.block_offset);
+
+    const out = try alloc.alloc(XattrOwned, lookup.count);
+    errdefer alloc.free(out);
+
+    for (0..lookup.count) |i| {
+        const key_entry: KeyEntry = undefined;
+        try meta.interface.readSliceEndian(KeyEntry, @ptrCast(&key_entry), .little);
+
+        const key = switch (key_entry.type.namespace) {
+            .user => blk: {
+                const tmp = try alloc.alloc(u8, key_entry.name_size + 1 + 5);
+                errdefer alloc.free(tmp);
+                try meta.interface.readSliceEndian(u8, tmp[5 .. tmp.len - 1], .little);
+                @memset(tmp[0..5], "user.");
+                break :blk tmp;
+            },
+            .trusted => blk: {
+                const tmp = try alloc.alloc(u8, key_entry.name_size + 1 + 8);
+                errdefer alloc.free(tmp);
+                try meta.interface.readSliceEndian(u8, tmp[8 .. tmp.len - 1], .little);
+                @memset(tmp[0..8], "trusted.");
+                break :blk tmp;
+            },
+            .security => blk: {
+                const tmp = try alloc.alloc(u8, key_entry.name_size + 1 + 9);
+                errdefer alloc.free(tmp);
+                try meta.interface.readSliceEndian(u8, tmp[9 .. tmp.len - 1], .little);
+                @memset(tmp[0..9], "security.");
+                break :blk tmp;
+            },
+        };
+        key[key.len - 1] = 0;
+        errdefer alloc.free(key);
+
+        if (key_entry.type.out_of_line) {
+            const value: ValueOutOfLineEntry = undefined;
+            try meta.interface.readSliceEndian(ValueOutOfLineEntry, @ptrCast(&value), .little);
+
+            var ool_rdr = try fil.readerAt(io, kv_start + value.ref.block_start, &[0]u8{});
+            var ool_meta: MetadataReader = .init(alloc, &ool_rdr.interface, decomp);
+            try ool_meta.interface.discardAll(value.ref.block_offset);
+
+            var val_size: u32 = undefined;
+            try ool_meta.interface.readSliceEndian(val_size, @ptrCast(&val_size), .little);
+
+            const val = try alloc.alloc(u8, val_size);
+            errdefer alloc.free(val);
+            try ool_meta.interface.readSliceEndian(u8, val, .little);
+
+            out[i] = .{
+                .key = key,
+                .value = val,
+            };
+            continue;
+        }
+
+        var val_size: u32 = undefined;
+        try meta.interface.readSliceEndian(val_size, @ptrCast(&val_size), .little);
+
+        const val = try alloc.alloc(u8, val_size);
+        errdefer alloc.free(val);
+        try meta.interface.readSliceEndian(u8, val, .little);
+
+        out[i] = .{
+            .key = key,
+            .value = val,
+        };
+    }
+    return out;
+}