Work on extraction

Created DataExtractor & DataReader
Created Lookup tables

.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

@@ -1,101 +1,125 @@
 const std = @import("std");
+const Build = std.Build;
 
 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 allow_lzo = b.option(bool, "allow_lzo", "Compile with lzo support") orelse false;
+    const allow_lzo = b.option(bool, "allow_lzo", "Compile with lzo decompression support.") orelse false;
+    const dynamic = b.option(bool, "dynamic", "Dynamic link C decompression libraries.") orelse false;
     const debug = b.option(bool, "debug", "Enable options to make debugging easier.") orelse false;
-    const version_string_option = b.option([]const u8, "version", "Version of the library/binary");
+    const version_string = b.option([]const u8, "version", "Version of the library/binary") orelse "0.0.0-testing";
+
+    const version: std.SemanticVersion = try .parse(version_string);
 
     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"),
+    const target = b.standardTargetOptions(.{});
+
+    const c = b.addTranslateC(.{
+        .optimize = optimize,
         .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,
+        .root_source_file = b.path("src/c.h"),
     });
-    mod.addOptions("config", zig_squashfs_options);
-    if (!use_zig_decomp) {
-        var zlib_ng = b.dependency("zlib_ng", .{});
-        mod.linkLibrary(zlib_ng.artifact("zng"));
-
-        mod.linkSystemLibrary("lzma", .{ .preferred_link_mode = .static });
-        if (allow_lzo == true)
-            mod.linkSystemLibrary("minilzo", .{ .preferred_link_mode = .static });
-
-        var lz4 = b.dependency("lz4", .{});
-        mod.linkLibrary(lz4.artifact("lz4"));
-
-        var zstd = b.dependency("zstd", .{});
-        mod.linkLibrary(zstd.artifact("zstd"));
+    if (allow_lzo)
+        c.defineCMacro("ALLOW_LZO", null);
+    if (dynamic) {
+        c.linkSystemLibrary("z", .{});
+        c.linkSystemLibrary("lzma", .{});
+        c.linkSystemLibrary("lz4", .{});
+        c.linkSystemLibrary("zstd", .{});
+        if (allow_lzo)
+            c.linkSystemLibrary("minilzo", .{});
     }
 
-    var version = version_string_option orelse "0.0.0-testing";
-    if (version[0] == 'v') version = version[1..];
-    const unsquashfs_options = b.addOptions();
-    unsquashfs_options.addOption(
-        std.SemanticVersion,
-        "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 deps = try getDependencies(b, optimize, target, allow_lzo);
 
     const lib = b.addLibrary(.{
         .name = "squashfs",
-        .root_module = mod,
         .use_llvm = debug,
+        .version = version,
+        .root_module = b.createModule(.{
+            .imports = &.{
+                .{ .name = "options", .module = zig_squashfs_options.createModule() },
+                .{ .name = "c", .module = c.createModule() },
+            },
+            .optimize = optimize,
+            .target = target,
+            .root_source_file = b.path("src/root.zig"),
+            .valgrind = debug,
+        }),
     });
 
+    for (deps) |d|
+        lib.root_module.linkLibrary(d);
+
     b.installArtifact(lib);
+
+    const exe_config = b.addOptions();
+    exe_config.addOption(std.SemanticVersion,"version", version);
+
+    const exe = b.addExecutable(.{
+        .name = "unsquashfs",
+        .use_llvm = debug,
+        .version = version,
+        .root_module = b.createModule(.{
+            .optimize = optimize,
+            .target = target,
+            .root_source_file = b.path("src/bin/unsquashfs.zig"),
+            .valgrind = debug,
+            .imports = &.{
+                .{ .name = "config", .module = exe_config.createModule() },
+                .{ .name = "squashfs", .module = lib.root_module }
+            },
+        }),
+    });
+
     b.installArtifact(exe);
 
-    const mod_tests = b.addTest(.{
-        .root_module = mod,
+    const lib_test = b.addTest(.{
+        .name = "squashfs-test",
+        .root_module = lib.root_module,
     });
-    const run_mod_tests = b.addRunArtifact(mod_tests);
-    const exe_tests = b.addTest(.{
+    const test_step = b.step("test", "Run tests");
+    test_step.dependOn(&lib_test.step);
+
+    // zls check step
+    const lib_check = b.addLibrary(.{
+        .name = "squashfs-check",
+        .root_module = lib.root_module,
+    });
+    const exe_check = b.addLibrary(.{
+        .name = "unsquashfs-check",
         .root_module = exe.root_module,
     });
-    const run_exe_tests = b.addRunArtifact(exe_tests);
-    const test_step = b.step("test", "Run tests");
-    test_step.dependOn(&run_mod_tests.step);
-    test_step.dependOn(&run_exe_tests.step);
 
-    // zls build check steps
-    const lib_check = b.addLibrary(.{
-        .name = "squashfs",
-        .root_module = mod,
-    });
-    const exe_check = b.addExecutable(.{
-        .name = "unsquashfs",
-        .root_module = exe_mod,
-    });
-    const check = b.step("check", "Check if unsquashfs compiles");
+    const check = b.step("check", "Check if squashfs compiles");
     check.dependOn(&lib_check.step);
     check.dependOn(&exe_check.step);
 }
+
+fn getDependencies(b: *Build, optimize: std.builtin.OptimizeMode, target: Build.ResolvedTarget, allow_lzo: bool) ![]*Build.Step.Compile {
+    const alloc = b.allocator;
+
+    var list: std.ArrayList(*Build.Step.Compile) = .empty;
+
+    const zlib_ng = b.dependency("zlib_ng", .{ .optimize = optimize, .target = target });
+    try list.append(alloc, zlib_ng.artifact("zng"));
+
+    const xz = b.dependency("xz", .{ .optimize = optimize, .target = target });
+    try list.append(alloc, xz.artifact("lzma"));
+
+    const lz4 = b.dependency("lz4", .{ .optimize = optimize, .target = target });
+    try list.append(alloc, lz4.artifact("lz4"));
+
+    const zstd = b.dependency("zstd", .{ .optimize = optimize, .target = target });
+    try list.append(alloc, zstd.artifact("zstd"));
+
+    if (allow_lzo) {
+        const minilzo = b.dependency("minilzo", .{ .optimize = optimize, .target = target });
+        try list.append(alloc, minilzo.artifact("minilzo"));
+    }
+
+    return list.toOwnedSlice(b.allocator);
+}

build.zig.zon

@@ -2,7 +2,7 @@
     .name = .squashfs,
     .version = "0.0.6",
     .fingerprint = 0x37ba29474b87f145, // Changing this has security and trust implications.
-    .minimum_zig_version = "0.15.2",
+    .minimum_zig_version = "0.16.0",
     .dependencies = .{
         .zlib_ng = .{
             .url = "git+https://github.com/CalebQ42/zig-zlib-ng#5f2f02dfb28acca2517dacbbd09e9b987f57b133",
@@ -16,6 +16,14 @@
             .url = "git+https://github.com/allyourcodebase/lz4.git?ref=1.10.0-6#41f52ab227caf9d48cf88c89a4d2946caa12b102",
             .hash = "lz4-1.10.0-6-ewyzw-4NAAAWDpY4xpiqr4LQhZQAC0x_rGnW2iPh6jk2",
         },
+        .minilzo = .{
+            .url = "git+https://github.com/CalebQ42/zig-minilzo.git#7cbae997b91a44d74b7cd6c073584dc9562a6c90",
+            .hash = "minilzo-2.10.0-Ij7BO8wLAADeWI4Pe4jp8XTDsDaquZR14oZ7_9yKKDWP",
+        },
+        .xz = .{
+            .url = "git+https://github.com/akunaakwei/zig-xz.git#e2d389262c8291907e3e4c6fb119819141c16c0f",
+            .hash = "xz-5.8.2-6v47_JYeAABSL-jonprpL5-E_YaaGc4B5xrbe93WsJ3G",
+        },
     },
     .paths = .{
         "build.zig",

src/archive.zig

@@ -1,97 +1,185 @@
-//! 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 File = Io.File;
+const MemoryMap = File.MemoryMap;
 
 const Decomp = @import("decomp.zig");
+const DecompCache = @import("decomp_cache.zig");
+const Extract = @import("extract.zig");
 const ExtractionOptions = @import("options.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 MetadataReader = @import("util/metadata.zig");
-const OffsetFile = @import("util/offset_file.zig");
-const XattrTable = @import("xattr.zig");
-
-const config = if (builtin.is_test) .{
-    .use_zig_decomp = !builtin.link_libc,
-    .allow_lzo = false,
-} else @import("config");
 
 const Archive = @This();
 
-alloc: std.mem.Allocator,
-
-fil: OffsetFile,
-decomp: Decomp.DecompFn,
+const CACHE_MEM_MAX = 1024 * 1024 * 1024;
 
 super: Superblock,
 
-tables: ?Tables = null,
+cache: DecompCache,
 
-/// 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(alloc: std.mem.Allocator, io: Io, fil: File) !Archive {
+    return initAdvanced(alloc, io, fil, 0, 0);
+}
+pub fn initAdvanced(alloc: std.mem.Allocator, io: Io, fil: File, offset: u64, cache_memory_max: u64) !Archive {
+    var rdr = fil.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 rdr.interface.readSliceEndian(Superblock, @ptrCast(&super), .little);
     try super.validate();
-    const off_fil: OffsetFile = .init(fil, offset);
-    const decomp: Decomp.DecompFn = switch (super.compression) {
-        .gzip => Decomp.gzipDecompress,
-        .lzma => Decomp.lzmaDecompress,
-        .xz => Decomp.xzDecompress,
-        .zstd => Decomp.zstdDecompress,
-        .lz4 => if (!config.use_zig_decomp) Decomp.cLz4 else return error.Lz4Unsupported,
-        .lzo => if (!config.use_zig_decomp and config.allow_lzo) Decomp.lzoDecompress else return error.LzoUnsupported,
-    };
+
+    const map = try fil.createMemoryMap(io, .{
+        .offset = offset,
+        .len = super.size,
+        .protection = .{ .read = true },
+    });
+
     return .{
-        .alloc = alloc,
-        .fil = off_fil,
-        .decomp = decomp,
         .super = super,
+
+        .cache = try .init(
+            alloc,
+            map,
+            super.compression,
+            if (cache_memory_max != 0)
+                cache_memory_max
+            else
+                @min(CACHE_MEM_MAX, (try std.process.totalSystemMemory()) / 2),
+        ),
     };
 }
-pub fn deinit(self: *Archive) void {
-    if (self.tables != null)
-        self.tables.?.deinit();
+pub fn deinit(self: *Archive, io: Io) void {
+    self.cache.deinit(io);
 }
 
-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);
+pub fn root(self: *Archive, alloc: std.mem.Allocator, io: Io) !SfsFile {
+    const inode: Inode = try .initRef(
+        alloc,
+        io,
+        &self.cache,
+        self.super.inode_start,
+        self.super.block_size,
+        self.super.root_ref,
+    );
+    return .init(alloc, self, inode, "");
+}
+pub fn open(self: *Archive, alloc: std.mem.Allocator, io: Io, filepath: []const u8) !SfsFile {
+    const path = std.mem.trim(u8, filepath, "/");
+
+    var root_file = try self.root(alloc, io);
+
+    if (path.len == 0 or path[0] == '.') return root_file;
+
+    defer root_file.deinit();
+    return root_file.open(alloc, io, filepath);
 }
 
-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, "");
+pub fn extract(self: *Archive, alloc: std.mem.Allocator, io: Io, ext_loc: []const u8, options: ExtractionOptions) !void {
+    const root_inode: Inode = try .initRef(
+        alloc,
+        io,
+        &self.cache,
+        self.super.inode_start,
+        self.super.block_size,
+        self.super.root_ref,
+    );
+    return Extract.extract(alloc, io, root_inode, &self.cache, self.super, ext_loc, options);
 }
 
-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);
+// Superblock
+
+pub const Superblock = extern struct {
+    magic: u32,
+    inode_count: u32,
+    mod_time: u32,
+    block_size: u32,
+    frag_count: u32,
+    compression: Decomp.Enum,
+    block_log: u16,
+    flags: packed struct(u16) {
+        inode_uncompressed: bool,
+        data_uncompressed: bool,
+        check: bool,
+        frag_uncompressed: bool,
+        frag_never: bool,
+        frag_always: bool,
+        de_dupe: bool,
+        exportable: bool,
+        xattr_uncompressed: bool,
+        xattr_never: bool,
+        compression_options: bool,
+        id_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,
+
+    pub fn validate(self: Superblock) !void {
+        if (self.magic != std.mem.readInt(u32, "hsqs", .little))
+            return error.BadMagic;
+        if (self.ver_maj != 4 or self.ver_min != 0)
+            return error.InvalidVersion;
+        if (self.block_log != std.math.log2(self.block_size))
+            return error.BadBlockLog;
+        if (self.flags.check)
+            return error.BadCheckFlag;
+    }
+};
+
+// Test
+
+const TestArchive = "testing/LinuxPATest.sfs";
+
+test "Basics" {
+    const alloc = std.testing.allocator;
+    const io = std.testing.io;
+
+    var archive_file = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer archive_file.close(io);
+    var arc: Archive = try .init(alloc, io, archive_file);
+    defer arc.deinit(io);
+
+    var root_file = try arc.root(alloc, io);
+    defer root_file.deinit();
 }
 
-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 TestFile = "Start.exe";
+const TestFileExtractLocation = "testing/Start.exe";
+
+test "SingleFileExtraction" {
+    const alloc = std.testing.allocator;
+    const io = std.testing.io;
+
+    var archive_file = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer archive_file.close(io);
+    var arc: Archive = try .init(alloc, io, archive_file);
+    defer arc.deinit(io);
+
+    var ext_file = try arc.open(alloc, io, TestFile);
+    defer ext_file.deinit();
+
+    try ext_file.extract(alloc, io, TestFileExtractLocation, .default);
+}
+
+const TestFullExtractLocation = "testing/TestExtract";
+
+test "FullExtraction" {
+    const alloc = std.testing.allocator;
+    const io = std.testing.io;
+
+    var archive_file = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer archive_file.close(io);
+    var arc: Archive = try .init(alloc, io, archive_file);
+    defer arc.deinit(io);
+
+    try arc.extract(alloc, io, TestFullExtractLocation, .default);
 }

src/bin/unsquashfs.zig

@@ -1,9 +1,11 @@
 const std = @import("std");
-const Writer = std.Io.Writer;
+const Io = std.Io;
+const Writer = Io.Writer;
+const File = Io.File;
 const builtin = @import("builtin");
 
 const config = @import("config");
-const squashfs = @import("zig_squashfs");
+const squashfs = @import("squashfs");
 
 //TODO: Add more options
 const help_mgs =
@@ -38,40 +40,41 @@ 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 = File.stdout();
+    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: File = try Io.Dir.cwd().openFile(io, archive, .{}); //TODO: Handle error gracefully.
+    defer fil.close(io);
+    var arc: squashfs.Archive = try .initAdvanced(alloc, io, fil, offset, 0); //TODO: Update when memory size matters. //TODO: Handle error gracefully.
+    defer arc.deinit(io);
     const options: squashfs.ExtractionOptions = .{
-        .threads = if (threads == 0) try std.Thread.getCpuCount() else threads,
         .verbose = verbose,
         .verbose_writer = if (verbose) &out.interface else null,
         .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.skip(); // 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 +85,7 @@ 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 +93,7 @@ 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/c.h

@@ -0,0 +1,7 @@
+#include <zlib.h>
+#include <lzma.h>
+#include <lz4.h>
+#include <zstd.h>
+#ifdef ALLOW_LZO
+#include <lzo/minilzo.h>
+#endif

src/c_decomp.zig

@@ -0,0 +1,61 @@
+const std = @import("std");
+
+const c = @import("c");
+
+const Error = @import("decomp.zig").Error;
+
+pub fn zlibDecompress(_: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var strem: c.z_stream = .{
+        .next_in = in.ptr,
+        .avail_in = @truncate(in.len),
+        .next_out = out.ptr,
+        .avail_out = @truncate(out.len),
+    };
+    var res = c.inflateInit(&strem);
+    if (res != c.Z_OK) return Error.ReadFailed;
+    defer _ = c.inflateEnd(&strem);
+
+    res = c.inflate(&strem, c.Z_FULL_FLUSH);
+    if (res != c.Z_OK) return Error.ReadFailed;
+
+    return strem.total_out;
+}
+pub fn lzmaDecompress(_: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var strem: 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(&strem, out.len * 2, 0);
+    if (res != c.LZMA_OK) return Error.ReadFailed;
+    defer c.lzma_end(&strem);
+
+    while (res == c.LZMA_OK)
+        res = c.lzma_code(&strem, c.LZMA_RUN);
+    if (res != c.LZMA_FINISH) return Error.ReadFailed;
+
+    return strem.total_out;
+}
+pub fn lzoDecompress(_: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var out_len = out.len;
+    const res = c.lzo1x_decompress(in.ptr, in.len, out.ptr, &out_len, null);
+    if (res != c.LZO_E_OK) return Error.ReadFailed;
+    return out_len;
+}
+pub fn lz4Decompress(_: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    const res = c.LZ4_decompress_safe(
+        in.ptr,
+        out.ptr,
+        @bitCast(@as(u32, @truncate(in.len))),
+        @bitCast(@as(u32, @truncate(out.len))),
+    );
+    if (res < 0) return Error.ReadFailed;
+    return @abs(res);
+}
+pub fn zstdDecompress(_: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    const res = c.ZSTD_decompress(out.ptr, out.len, in.ptr, in.len);
+    if (c.ZSTD_isError(res) != 0)
+        return Error.ReadFailed;
+    return res;
+}

src/data/extractor.zig

@@ -0,0 +1,102 @@
+const std = @import("std");
+const Io = std.Io;
+
+const DecompCache = @import("../decomp_cache.zig");
+const DataBlock = @import("../inode.zig").DataBlock;
+
+const Extractor = @This();
+
+cache: *DecompCache,
+block_size: u32,
+
+start: u64,
+size: u64,
+blocks: []DataBlock,
+
+frag_data: ?[]u8 = null,
+frag_offset: u32 = 0,
+
+pub fn init(cache: *DecompCache, block_size: u32, size: u64, start: u64, blocks: []DataBlock) Extractor {
+    return .{
+        .cache = cache,
+        .block_size = block_size,
+
+        .start = start,
+        .size = size,
+        .blocks = blocks,
+    };
+}
+
+pub fn addFragment(self: *Extractor, data: []u8, offset: u32) void {
+    self.frag_data = data;
+    self.frag_offset = offset;
+}
+
+pub fn asyncExtract(self: Extractor, io: Io, fil: Io.File) Error!void {
+    try fil.writePositionalAll(io, &.{&.{0}}, self.size - 1);
+
+    var map = try fil.createMemoryMap(io, .{ .len = self.size, .protection = .{ .write = true } });
+    defer map.destroy(io);
+
+    var group: Io.Group = .init;
+    defer group.cancel(io);
+
+    var ret_err: ?Error = null;
+
+    var offset = self.start;
+    for (0..self.blocks.len) |i| {
+        group.async(io, blockThread, .{ self, io, map, offset, i, &ret_err });
+
+        offset += self.blocks[i].size;
+    }
+    if (self.frag_data != null)
+        group.async(io, fragThread, .{ self, map });
+
+    group.await(io) catch |err| return ret_err orelse err;
+
+    try map.write(io);
+}
+
+fn blockThread(self: Extractor, io: Io, map: Io.File.MemoryMap, read_offset: u64, idx: usize, ret_err: *?Error) error{Canceled}!void {
+    const write_pos = idx * self.block_size;
+    const size = if (self.frag_data == null and idx == self.block_size.len - 1)
+        self.size % self.block_size
+    else
+        self.block_size;
+    const block = self.blocks[idx];
+
+    if (block.size == 0) {
+        @memset(map.memory[write_pos..][0..size], 0);
+        return;
+    }
+    if (block.uncompressed) {
+        @memcpy(map[write_pos..][0..size], self.cache.map.memory[read_offset..][0..size]);
+        return;
+    }
+    const data = self.cache.get(io, read_offset, block.size, size) catch |err| switch (err) {
+        error.Canceled => {
+            io.recancel();
+            return error.Canceled;
+        },
+        else => |e| {
+            ret_err.* = e;
+            return error.Canceled;
+        },
+    };
+    defer self.cache.finished(io, read_offset);
+    if (data.len != size) {
+        std.debug.print("Size of decompression at {} is {} and should be {}\n", .{ read_offset, data.len, size });
+        return Error.BadDecompressionSize;
+    }
+    @memcpy(map[write_pos..][0..size], data);
+}
+fn fragThread(self: Extractor, map: Io.File.MemoryMap) error{Canceled}!void {
+    const write_pos = self.blocks.len * self.block_size;
+    const size = self.size % self.block_size;
+
+    @memcpy(map.memory[write_pos..][0..size], self.frag_data.?[self.frag_offset..][0..size]);
+}
+
+// Types
+
+pub const Error = error{BadDecompressionSize} || Io.File.WritePositionalError || Io.File.MemoryMap.CreateError;

src/data/reader.zig

@@ -0,0 +1,151 @@
+const std = @import("std");
+const Io = std.Io;
+
+const DecompCache = @import("../decomp_cache.zig");
+const DataBlock = @import("../inode.zig").DataBlock;
+
+const Reader = @This();
+
+io: Io,
+
+cache: *DecompCache,
+block_size: u32,
+
+size: u64,
+blocks: []DataBlock,
+
+frag_data: ?[]u8 = null,
+frag_offset: u32 = 0,
+
+cur_offset: u64 = 0,
+next_offset: u64,
+
+idx: u32 = 0,
+cur_block_sparse: bool = false,
+
+interface: Io.Reader = .{
+    .buffer = &[0]u8{},
+    .end = 0,
+    .seek = 0,
+    .vtable = &.{
+        .stream = stream,
+        .discard = discard,
+        .readVec = readVec,
+    },
+},
+
+pub fn init(io: Io, cache: *DecompCache, block_size: u32, size: u64, start: u64, blocks: []DataBlock) Reader {
+    return .{
+        .io = io,
+
+        .cache = cache,
+        .block_size = block_size,
+
+        .size = size,
+        .blocks = blocks,
+
+        .next_offset = start,
+    };
+}
+pub fn deinit(self: Reader) void {
+    self.cache.finished(self.io);
+}
+
+pub fn addFragment(self: *Reader, data: []u8, offset: u32) void {
+    self.frag_data = data;
+    self.frag_offset = offset;
+}
+
+fn advance(self: *Reader) Io.Reader.Error!void {
+    errdefer self.interface.end = 0;
+    self.interface.seek = 0;
+
+    if (self.idx > self.blocks.len) return error.EndOfStream;
+    defer self.idx += 1;
+    self.cache.finished(self.io, self.cur_offset);
+
+    if (self.idx == self.blocks.len) {
+        if (self.frag_data == null) return error.EndOfStream;
+        self.cur_offset = 0;
+
+        const size = self.size % self.block_size;
+        self.interface.buffer = self.frag_data.?[self.frag_offset..][0..size];
+        self.interface.end = size;
+        return;
+    }
+
+    const block = self.blocks[self.idx];
+
+    const size = if (self.idx == self.blocks.len - 1 and self.frag_data == null)
+        self.size % self.block_size
+    else
+        self.block_size;
+
+    if (block.size == 0) {
+        self.interface.buffer = &[0]u8{};
+        self.cur_block_sparse = true;
+        self.interface.end = size;
+        return;
+    } else {
+        self.cur_block_sparse = false;
+    }
+
+    self.cur_offset = self.next_offset;
+    self.next_offset = self.cur_offset + block.size;
+
+    if (block.uncompressed) {
+        self.interface.buffer = self.cache.map.memory[self.cur_offset..][0..size];
+        self.interface.end = size;
+        return;
+    }
+    const data = self.cache.get(self.io, self.cur_offset, block.size, size);
+    if (data.len != size) {
+        std.debug.print("Size of decompression at {} is {} and should be {}\n", .{ self.cur_offset, data.len, size });
+        return Io.Reader.Error.ReadFailed;
+    }
+    self.interface.buffer = data;
+    self.interface.end = size;
+}
+
+fn stream(r: *Io.Reader, w: *Io.Writer, limit: Io.Limit) Io.Reader.StreamError!usize {
+    const self: *Reader = @fieldParentPtr("interface", r);
+    if (r.seek >= r.end) {
+        try self.advance();
+    }
+    const to_write = @min(@intFromEnum(limit), r.end - r.seek);
+    const wrote = try if (self.cur_block_sparse)
+        w.splatByte(0, to_write)
+    else
+        w.write(r.buffer[r.seek..][0..to_write]);
+    r.seek += wrote;
+    return wrote;
+}
+fn discard(r: *Io.Reader, limit: Io.Limit) Io.Reader.Error!usize {
+    if (r.seek >= r.end) {
+        const self: *Reader = @fieldParentPtr("interface", r);
+        try self.advance();
+    }
+    const to_discard = @min(@intFromEnum(limit), r.end - r.seek);
+    r.seek += to_discard;
+    return to_discard;
+}
+fn readVec(r: *Io.Reader, vec: [][]u8) Io.Reader.Error!usize {
+    const self: *Reader = @fieldParentPtr("interface", r);
+    if (r.seek >= r.end) {
+        try self.advance();
+    }
+    var total: usize = 0;
+    for (vec) |v| {
+        const to_copy = @min(v.len, r.end - r.seek);
+        if (self.cur_block_sparse) {
+            @memset(v[0..to_copy], 0);
+        } else {
+            @memcpy(v[0..to_copy], r.buffer[r.seek..][0..to_copy]);
+        }
+        total += to_copy;
+        r.seek += to_copy;
+
+        if (r.seek >= r.end) break;
+    }
+    return total;
+}

src/decomp.zig

@@ -1,27 +1,14 @@
-//! Implementations for decompression.
-//! TODO: change to vtable interface to allow for shared decompressors for better performance/resource usage.
-
 const std = @import("std");
-const Reader = std.Io.Reader;
-const builtin = @import("builtin");
 
-const config = if (builtin.is_test) .{
-    .use_zig_decomp = !builtin.link_libc,
-    .allow_lzo = false, // Change once LZO compilation is fixed
-} else @import("config");
+const options = @import("options");
 
-const c = @cImport({
-    @cInclude("zlib-ng.h");
-    @cInclude("lzma.h");
-    @cInclude("lz4.h");
-    @cInclude("zstd.h");
-    @cInclude("zstd_errors.h");
-    if (config.allow_lzo)
-        @cInclude("lzo/minilzo.h");
-});
+const c_decomp = @import("c_decomp.zig");
+const zig_decomp = @import("zig_decomp.zig");
 
-pub const CompressionType = enum(u16) {
-    gzip = 1,
+pub const Error = error{} || std.Io.Reader.UnlimitedAllocError;
+
+pub const Enum = enum(u16) {
+    zlib = 1,
     lzma,
     lzo,
     xz,
@@ -29,233 +16,26 @@ pub const CompressionType = enum(u16) {
     zstd,
 };
 
-pub const DecompFn = *const fn (alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize; // TODO: replace anyerror to definitive error types.
+pub const Fn = *const fn (std.mem.Allocator, in: []u8, out: []u8) Error!usize;
 
-pub const gzipDecompress = if (!config.use_zig_decomp) cGzip else zigGzip;
-
-fn zigGzip(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 fn DecompFn(comp: Enum) !Fn {
+    return if (options.use_zig_decomp)
+        switch (comp) {
+            .zlib => zig_decomp.zlibDecompress,
+            .lzma => zig_decomp.lzmaDecompress,
+            .xz => zig_decomp.xzDecompress,
+            .zstd => zig_decomp.zstdDecompress,
+            .lz4 => error.Lz4Unsupported,
+            .lzo => error.LzoUnsupported,
         }
-fn cGzip(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    _ = alloc;
-    var out_len: usize = 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 => error.NotEnoughMemory,
-        c.Z_BUF_ERROR => error.OutBufferTooSmall,
-        c.Z_DATA_ERROR => error.BadData,
-        else => error.UnknownResult,
+    else switch (comp) {
+        .zlib => c_decomp.zlibDecompress,
+        .lzma, .xz => c_decomp.lzmaDecompress,
+        .zstd => c_decomp.zstdDecompress,
+        .lz4 => c_decomp.lz4Decompress,
+        .lzo => if (options.allow_lzo)
+            c_decomp.zstdDecompress
+        else
+            error.LzoUnsupported,
     };
 }
-
-pub const lzmaDecompress = if (!config.use_zig_decomp) cLzma else zigLzma;
-
-fn zigLzma(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);
-}
-fn cLzma(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    _ = alloc;
-    var stream: c.lzma_stream = .{
-        .next_in = in.ptr,
-        .avail_in = in.len,
-        .next_out = out.ptr,
-        .avail_out = out.len,
-    };
-    var res = c.lzma_alone_decoder(&stream, in.len * 2);
-    switch (res) {
-        c.LZMA_OK => {},
-        c.LZMA_MEM_ERROR => return error.LzmaMemoryError,
-        c.LZMA_PROG_ERROR => return error.LzmaProgramError,
-        else => return error.UnknownResult,
-    }
-    defer c.lzma_end(&stream);
-    while (res == c.LZMA_OK)
-        res = c.lzma_code(&stream, c.LZMA_RUN);
-    return switch (res) {
-        c.LZMA_STREAM_END => stream.total_out,
-        c.LZMA_MEM_ERROR => error.LzmaMemoryError,
-        c.LZMA_MEMLIMIT_ERROR => error.LzmaMemoryLimit,
-        c.LZMA_FORMAT_ERROR => error.LzmaBadFormat,
-        c.LZMA_DATA_ERROR => error.LzmaDataCorrupt,
-        c.LZMA_BUF_ERROR => error.LzmaCannotProgress,
-        c.LZMA_PROG_ERROR => error.LzmaProgramError,
-        else => error.UnknownResult,
-    };
-}
-
-// pub const lzoDecompress = if (!config.use_zig_decomp) cLzo else zigLzo;
-
-// fn zigLzo(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-//     _ = alloc;
-//     _ = in;
-//     _ = out;
-//     return error.LzoUnsupported;
-// }
-pub fn cLzo(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    _ = alloc;
-    var res = c.lzo_init();
-    if (res != 0) return error.LzoInitFailed;
-    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_ERROR => error.LzoError,
-        c.LZO_E_OUT_OF_MEMORY => error.LzoOutOfMemory,
-        c.LZO_E_NOT_COMPRESSIBLE => error.LzoNotCompressible,
-        c.LZO_E_INPUT_OVERRUN => error.LzoInputOverrun,
-        c.LZO_E_OUTPUT_OVERRUN => error.LzoOutputOverrun,
-        c.LZO_E_LOOKBEHIND_OVERRUN => error.LzoLookbehindOverrun,
-        c.LZO_E_EOF_NOT_FOUND => error.LzoEofNotFound,
-        c.LZO_E_INPUT_NOT_CONSUMED => error.LzoInputNotConsumed,
-        c.LZO_E_NOT_YET_IMPLEMENTED => error.LzoNotYetImplemented,
-        c.LZO_E_INVALID_ARGUMENT => error.LzoInvalidArgument,
-        c.LZO_E_INVALID_ALIGNMENT => error.LzoInvalidAlignment,
-        c.LZO_E_OUTPUT_NOT_CONSUMED => error.LzoOutputNotConsumed,
-        c.LZO_E_INTERNAL_ERROR => error.LzoInternalError,
-        else => error.UnknownResult,
-    };
-}
-
-pub const xzDecompress = if (!config.use_zig_decomp) cXz else zigXz;
-
-fn zigXz(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);
-}
-fn cXz(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    _ = alloc;
-    var stream: c.lzma_stream = .{
-        .next_in = in.ptr,
-        .avail_in = in.len,
-        .next_out = out.ptr,
-        .avail_out = out.len,
-        // .allocator = _, TODO: create a custom allocator based on alloc,
-    };
-    var res = c.lzma_stream_decoder(&stream, in.len * 2, 0);
-    switch (res) {
-        c.LZMA_OK => {},
-        c.LZMA_MEM_ERROR => return error.LzmaMemoryError,
-        c.LZMA_PROG_ERROR => return error.LzmaProgramError,
-        else => return error.UnknownResult,
-    }
-    defer c.lzma_end(&stream);
-    while (res == c.LZMA_OK)
-        res = c.lzma_code(&stream, c.LZMA_RUN);
-    return switch (res) {
-        c.LZMA_STREAM_END => stream.total_out,
-        c.LZMA_MEM_ERROR => error.LzmaMemoryError,
-        c.LZMA_MEMLIMIT_ERROR => error.LzmaMemoryLimit,
-        c.LZMA_FORMAT_ERROR => error.LzmaBadFormat,
-        c.LZMA_DATA_ERROR => error.LzmaDataCorrupt,
-        c.LZMA_BUF_ERROR => error.LzmaCannotProgress,
-        c.LZMA_PROG_ERROR => error.LzmaProgramError,
-        else => error.UnknownResult,
-    };
-}
-
-// pub const lz4Decompress = if (!config.use_zig_decomp) cLz4 else zigLz4;
-
-// fn zigLz4(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-//     _ = alloc;
-//     _ = in;
-//     _ = out;
-//     return error.Lz4Unsupported;
-// }
-pub fn cLz4(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    _ = alloc;
-    const res = c.LZ4_decompress_safe(in.ptr, out.ptr, @intCast(in.len), @intCast(out.len));
-    if (res > 0) return @abs(res); // TODO: Find out what error values it can return.
-    return error.Lz4DecompressFailed;
-}
-
-pub const zstdDecompress = if (!config.use_zig_decomp) cZstd else zigZstd;
-
-pub fn zigZstd(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;
-    };
-}
-fn cZstd(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
-    _ = alloc;
-    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_prefix_unknown => cZstdError.PrefixUnknown,
-        c.ZSTD_error_version_unsupported => cZstdError.VersionUnsupported,
-        c.ZSTD_error_frameParameter_unsupported => cZstdError.FrameParameterUnsupported,
-        c.ZSTD_error_frameParameter_windowTooLarge => cZstdError.FrameParameterWindowTooLarge,
-        c.ZSTD_error_corruption_detected => cZstdError.CorruptionDetected,
-        c.ZSTD_error_checksum_wrong => cZstdError.ChecksumWrong,
-        c.ZSTD_error_literals_headerWrong => cZstdError.LiteralsHeaderWrong,
-        c.ZSTD_error_dictionary_corrupted => cZstdError.DictionaryCorrupted,
-        c.ZSTD_error_dictionary_wrong => cZstdError.DictionaryWrong,
-        c.ZSTD_error_dictionaryCreation_failed => cZstdError.DictionaryCreationFailed,
-        c.ZSTD_error_parameter_unsupported => cZstdError.ParameterUnsupported,
-        c.ZSTD_error_parameter_combination_unsupported => cZstdError.ParameterCombinationUnsupported,
-        c.ZSTD_error_parameter_outOfBound => cZstdError.ParameterOutOfBound,
-        c.ZSTD_error_tableLog_tooLarge => cZstdError.TableLogTooLarge,
-        c.ZSTD_error_maxSymbolValue_tooLarge => cZstdError.MaxSymbolValueTooLarge,
-        c.ZSTD_error_maxSymbolValue_tooSmall => cZstdError.MaxSymbolValueTooSmall,
-        c.ZSTD_error_stabilityCondition_notRespected => cZstdError.StabilityConditionNotRespected,
-        c.ZSTD_error_stage_wrong => cZstdError.StageWrong,
-        c.ZSTD_error_init_missing => cZstdError.InitMissing,
-        c.ZSTD_error_memory_allocation => cZstdError.MemoryAllocation,
-        c.ZSTD_error_workSpace_tooSmall => cZstdError.WorkSpaceTooSmall,
-        c.ZSTD_error_dstSize_tooSmall => cZstdError.DstSizeTooSmall,
-        c.ZSTD_error_srcSize_wrong => cZstdError.SrcSizeWrong,
-        c.ZSTD_error_dstBuffer_null => cZstdError.DstBufferNull,
-        c.ZSTD_error_noForwardProgress_destFull => cZstdError.NoForwardProgressDestFull,
-        c.ZSTD_error_noForwardProgress_inputEmpty => cZstdError.NoForwardProgressInputEmpty,
-        else => cZstdError.Generic,
-    };
-}
-
-pub const cZstdError = error{
-    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/decomp_cache.zig

@@ -0,0 +1,116 @@
+const std = @import("std");
+const Io = std.Io;
+const File = Io.File;
+const MemoryMap = File.MemoryMap;
+const Atomic = std.atomic.Value;
+
+const Decomp = @import("decomp.zig");
+
+const DecompCache = @This();
+
+alloc: std.mem.Allocator,
+map: MemoryMap,
+decomp_fn: Decomp.Fn,
+
+cache: std.AutoHashMap(u64, Cache),
+mut: std.Io.RwLock = .init,
+cond: std.Io.Condition = .init,
+
+max_mem: u64,
+cur_mem: u64 = 0,
+
+pub fn init(alloc: std.mem.Allocator, map: MemoryMap, compression: Decomp.Enum, max_mem: u64) !DecompCache {
+    return .{
+        .alloc = alloc,
+        .map = map,
+        .decomp_fn = try Decomp.DecompFn(compression),
+
+        .cache = .init(alloc),
+
+        .max_mem = max_mem,
+    };
+}
+pub fn deinit(self: *DecompCache, io: Io) void {
+    self.mut.lockUncancelable(io);
+
+    var iter = self.cache.valueIterator();
+    while (iter.next()) |v|
+        self.alloc.free(v.data);
+    self.cache.deinit();
+}
+
+pub fn get(self: *DecompCache, io: Io, offset: u64, compressed_size: u32, max_size: u32) ![]u8 {
+    {
+        try self.mut.lockShared(io);
+        defer self.mut.unlockShared(io);
+
+        const cache = self.cache.getPtr(offset);
+        if (cache != null) {
+            _ = cache.?.usage.fetchAdd(1, .acquire);
+            return cache.?.data;
+        }
+    }
+    try self.mut.lock(io);
+    defer self.mut.unlock(io);
+
+    const cache = try self.cache.getOrPut(offset);
+    if (cache.found_existing) {
+        _ = cache.value_ptr.usage.fetchAdd(1, .acquire);
+        return cache.value_ptr.data;
+    }
+    errdefer self.cache.removeByPtr(cache.key_ptr);
+
+    try self.ensureSpace(io, max_size);
+
+    var out = try self.alloc.alloc(u8, max_size);
+    errdefer self.alloc.free(out);
+
+    const decomp_size = try self.decomp_fn(self.alloc, self.map.memory[offset..][0..compressed_size], out);
+    if (decomp_size != max_size) {
+        if (!self.alloc.resize(out, decomp_size)) {
+            const new_out = try self.alloc.alloc(u8, decomp_size);
+            @memcpy(new_out, out[0..decomp_size]);
+            out = new_out;
+        } else {
+            out.len = decomp_size;
+        }
+    }
+    self.cur_mem += decomp_size;
+
+    cache.value_ptr.data = out;
+    _ = cache.value_ptr.usage.fetchAdd(1, .acquire);
+    return out;
+}
+pub fn finished(self: *DecompCache, io: Io, offset: u64) void {
+    const cache = self.cache.getPtr(offset);
+    if (cache == null) {
+        std.debug.print("Finished using cache, but cache does not exist: {}\n", .{offset});
+        return;
+    }
+    const use = cache.?.usage.fetchSub(1, .acquire);
+    if (use == 0)
+        self.cond.broadcast(io);
+}
+
+fn ensureSpace(self: *DecompCache, io: Io, size: u64) !void {
+    while (self.cur_mem + size > self.max_mem) {
+        var iter = self.cache.valueIterator();
+        while (iter.next()) |cache| {
+            if (cache.usage.load(.unordered) == 0) {
+                self.alloc.free(cache.data);
+                self.cur_mem -= cache.data.len;
+
+                if (self.cur_mem + size <= self.max_mem) return;
+            }
+        }
+        if (self.cur_mem + size <= self.max_mem) return;
+        try self.cond.wait(io, &self.mut.mutex);
+    }
+}
+
+// Types
+
+const Cache = struct {
+    data: []u8,
+    usage: Atomic(u32),
+};

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 +1,83 @@
+const std = @import("std");
+const Io = std.Io;
+const Reader = Io.Reader;
+
+const Inode = @import("inode.zig");
+
+const Directory = @This();
+
+entries: []Entry,
+
+pub fn init(alloc: std.mem.Allocator, rdr: *Reader, size: u32) Error!Directory {
+    if (size <= 3) return .{ .entries = &[0]Entry{} };
+
+    var entries: std.ArrayList(Entry) = try .initCapacity(alloc, 50);
+    errdefer {
+        for (entries.items) |ent|
+            ent.deinit(alloc);
+        entries.deinit(alloc);
+    }
+
+    var read: u32 = 3;
+    while (read < size) {
+        var hdr: Header = undefined;
+        try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
+        read += @sizeOf(Header);
+
+        try entries.ensureUnusedCapacity(alloc, hdr.count + 1);
+        for (0..hdr.count + 1) |_| {
+            var raw: RawEntry = undefined;
+            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);
+
+            entries.appendAssumeCapacity(.{
+                .inode_num = if (raw.inode_num_offset > 0)
+                    hdr.inode_num + @abs(raw.inode_num_offset)
+                else
+                    hdr.inode_num - @abs(raw.inode_num_offset),
+                .block_start = hdr.block_start,
+                .block_offset = raw.block_offset,
+                .type = raw.type,
+                .name = name,
+            });
+        }
+    }
+
+    return .{ .entries = try entries.toOwnedSlice(alloc) };
+}
+pub fn deinit(self: Directory, alloc: std.mem.Allocator) void {
+    for (self.entries) |entry|
+        entry.deinit(alloc);
+    alloc.free(self.entries);
+}
+
+// Types
+
+pub const Error = Reader.Error || std.mem.Allocator.Error;
+
+pub const Entry = struct {
+    inode_num: u32,
+    block_start: u32,
+    block_offset: u16,
+    type: Inode.Enum,
+    name: []const u8,
+
+    pub fn deinit(self: Entry, alloc: std.mem.Allocator) void {
+        alloc.free(self.name);
+    }
+};
+
+const Header = extern struct {
+    count: u32,
+    block_start: u32,
+    inode_num: u32,
+};
+const RawEntry = extern struct {
+    block_offset: u16,
+    inode_num_offset: i16,
+    type: Inode.Enum,
+    name_size: u16,
+};

src/extract.zig

@@ -0,0 +1,242 @@
+const std = @import("std");
+const Io = std.Io;
+
+const Atomic = std.atomic.Value;
+
+const DecompCache = @import("decomp_cache.zig");
+const ExtractionOptions = @import("options.zig");
+const Inode = @import("inode.zig");
+const Superblock = @import("archive.zig").Superblock;
+const Directory = @import("directory.zig");
+const DataExtractor = @import("data/extractor.zig");
+const DataReader = @import("data/reader.zig");
+
+pub fn extract(alloc: std.mem.Allocator, io: Io, inode: Inode, cache: *DecompCache, super: Superblock, ext_loc: []const u8, options: ExtractionOptions) !void {
+    const path = std.mem.trim(u8, ext_loc, "/");
+
+    var buf: [50]ReturnUnion = undefined;
+    var sel: Io.Select(ReturnUnion) = .init(io, &buf);
+    defer sel.cancelDiscard();
+
+    var ret_loop = io.async(returnLoop, .{ alloc, &sel, options });
+
+    try extractReal(alloc, io, cache, super, &sel, path, inode, null, false);
+
+    ret_loop.await(io) catch |err| {
+        // TODO: Drain sel
+        return err;
+    };
+}
+
+fn extractReal(
+    alloc: std.mem.Allocator,
+    io: Io,
+    cache: *DecompCache,
+    super: Superblock,
+    sel: *Io.Select(ReturnUnion),
+    path: []const u8,
+    inode: Inode,
+    parent: ?*Atomic(usize),
+    origin: bool,
+) Error!void {
+    try io.checkCancel();
+
+    switch (inode.data) {
+        .dir, .ext_dir => sel.async(
+            .dir_ret,
+            extractDir,
+            .{ alloc, io, cache, super, sel, path, inode, parent, origin },
+        ),
+        else => return error.Canceled,
+    }
+}
+
+fn extractDir(
+    alloc: std.mem.Allocator,
+    io: Io,
+    cache: *DecompCache,
+    super: Superblock,
+    sel: *Io.Select(ReturnUnion),
+    path: []const u8,
+    inode: Inode,
+    parent: ?*Atomic(usize),
+    origin: bool,
+) Error!DirReturn {
+    defer {
+        if (parent != null)
+            _ = parent.?.fetchSub(1, .acquire);
+        if (!origin) inode.deinit(alloc);
+    }
+    errdefer if (!origin) alloc.free(path);
+
+    const dir = inode.directory(alloc, io, cache, super.dir_start) catch |err| switch (err) {
+        error.NotDirectory => unreachable,
+        else => |e| return e,
+    };
+    defer dir.deinit(alloc);
+
+    const sub_files = try alloc.create(Atomic(usize));
+    sub_files.* = .init(dir.entries.len);
+
+    const ret: DirReturn = .{
+        .path = path,
+        .sub_files = sub_files,
+        .origin = origin,
+
+        .uid_idx = inode.hdr.uid_idx,
+        .gid_idx = inode.hdr.gid_idx,
+        .mod_time = inode.hdr.mod_time,
+        .permissions = inode.hdr.permission,
+
+        .xattr_idx = switch (inode.data) {
+            .ext_dir => |d| if (d.xattr_idx != 0xFFFFFFFF) d.xattr_idx else null,
+            else => null,
+        },
+    };
+
+    for (dir.entries) |entry| {
+        const new_inode: Inode = try .initDirEntry(alloc, io, cache, super.inode_start, super.block_size, entry);
+        errdefer new_inode.deinit(alloc);
+
+        const new_path = try std.mem.concat(alloc, u8, &.{ path, "/", entry.name });
+
+        try extractReal(
+            alloc,
+            io,
+            cache,
+            super,
+            sel,
+            new_path,
+            new_inode,
+            sub_files,
+            false,
+        );
+    }
+    return ret;
+}
+fn extractFile(
+    alloc: std.mem.Allocator,
+    io: Io,
+    cache: *DecompCache,
+    block_size: u32,
+    path: []const u8,
+    inode: Inode,
+    parent: ?*Atomic(usize),
+    origin: bool,
+) Error!FileReturn {
+    defer {
+        if (parent != null)
+            _ = parent.?.fetchSub(1, .acquire);
+        if (!origin) inode.deinit(alloc);
+    }
+    errdefer if (!origin) alloc.free(path);
+
+    const atomic = try Io.Dir.cwd().createFileAtomic(io, path, .{});
+    defer atomic.deinit(io);
+
+    var ret: FileReturn = .{
+        .path = path,
+        .origin = origin,
+
+        .uid_idx = inode.hdr.uid_idx,
+        .gid_idx = inode.hdr.gid_idx,
+        .permissions = inode.hdr.permission,
+        .mod_time = inode.hdr.mod_time,
+    };
+
+    var data: DataExtractor = switch (inode.data) {
+        .file => |f| blk: {
+            var data: DataExtractor = .init(cache, block_size, f.size, f.data_start, f.blocks);
+            if (f.frag_idx != 0xFFFFFFFF) {
+                // TODO
+            }
+            break :blk data;
+        },
+        .ext_file => |f| blk: {
+            var data: DataExtractor = .init(cache, block_size, f.size, f.data_start, f.blocks);
+            if (f.frag_idx != 0xFFFFFFFF) {
+                //TODO
+            }
+            break :blk data;
+        },
+        else => unreachable,
+    };
+
+    try atomic.link(io);
+    // return .{
+    //     .path = path,
+    // };
+    return error.Canceled;
+}
+
+// Loop
+
+fn returnLoop(alloc: std.mem.Allocator, sel: *Io.Select(ReturnUnion), options: ExtractionOptions) !void {
+    while (true) {
+        const finished = try sel.await();
+
+        switch (finished) {
+            .dir_ret => |d| {
+                const ret = try d;
+                if (ret.sub_files.load(.unordered) != 0) {
+                    sel.queue.putOne(sel.io, .{ .dir_ret = ret }) catch |err| {
+                        if (!ret.origin) alloc.free(ret.path);
+                        return err;
+                    };
+                    continue;
+                }
+                if (!ret.origin) alloc.free(ret.path);
+                alloc.destroy(ret.sub_files);
+
+                if (!options.ignore_permissions and !options.ignore_xattr) {
+                    // TODO: set permissions & xattr.
+                }
+            },
+            .file_ret => |f| {
+                const ret = try f;
+                if (!ret.origin) alloc.free(ret.path);
+
+                if (!options.ignore_permissions and !options.ignore_xattr) {
+                    // TODO: set permissions & xattr.
+                }
+            },
+            .void_ret => |v| try v,
+        }
+
+        if (sel.group.token.load(.unordered) == null) break;
+    }
+}
+
+// Utility types
+
+const ReturnUnion = union(enum) {
+    file_ret: Error!FileReturn,
+    dir_ret: Error!DirReturn,
+    void_ret: Error!void,
+};
+
+const Error = error{Canceled} || Directory.Error;
+
+const FileReturn = struct {
+    path: []const u8,
+    origin: bool,
+
+    uid_idx: u32,
+    gid_idx: u32,
+    mod_time: u32,
+    permissions: u16,
+
+    xattr_idx: ?u32 = null,
+};
+const DirReturn = struct {
+    path: []const u8,
+    sub_files: *Atomic(usize),
+    origin: bool,
+
+    uid_idx: u32,
+    gid_idx: u32,
+    mod_time: u32,
+    permissions: u16,
+
+    xattr_idx: ?u32 = null,
+};

src/file.zig

@@ -1,202 +1,102 @@
-//! A file/directory within the squashfs archive.
-
 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 Directory = @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 MetadataReader = @import("util/metadata.zig");
-
-const FileError = error{
-    NotDirectory,
-    NotRegularFile,
-    NotSymlink,
-    NotDevice,
-    NotFound,
-    ExtractionPathExists,
-};
 
 const SfsFile = @This();
 
+alloc: std.mem.Allocator,
 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);
-    @memcpy(new_name, name);
+/// The given allocator must have been used to create the Inode and name.
+pub fn init(alloc: std.mem.Allocator, archive: *Archive, inode: Inode, name: []const u8) SfsFile {
     return .{
+        .alloc = alloc,
         .archive = archive,
+
         .inode = inode,
+        .name = name,
+    };
+}
+pub fn initDirEntry(alloc: std.mem.Allocator, io: Io, archive: *Archive, entry: Directory.Entry) !SfsFile {
+    const new_name = try alloc.alloc(u8, entry.name.len);
+    defer alloc.free(new_name);
+    @memcpy(new_name, entry.name);
+
+    return .{
+        .alloc = alloc,
+        .archive = archive,
+
+        .inode = try .initDirEntry(
+            alloc,
+            io,
+            &archive.cache,
+            archive.super.inode_start,
+            archive.super.block_size,
+            entry,
+        ),
         .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);
-}
+/// Creates a new copy of the given SfsFile using the given allocator
+pub fn copy(self: SfsFile, alloc: std.mem.Allocator) !SfsFile {
+    const new_name = try alloc(u8, self.name.len);
+    errdefer alloc.free(new_name);
 
-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(),
+        .alloc = alloc,
         .archive = self.archive,
+
+        .inode = try self.inode.copy(alloc),
+        .name = new_name,
     };
 }
-/// 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();
-    defer {
-        for (entries) |e| {
-            e.deinit(alloc);
+pub fn deinit(self: SfsFile) void {
+    self.inode.deinit(self.alloc);
+    self.alloc.free(self.name);
 }
-        alloc.free(entries);
-    }
-    var cur_slice = entries;
-    var split = cur_slice.len / 2;
+
+/// Attempts to open the filepath if the SfsFile is a directory.
+/// If the given path refers to itself (such as "" or "."), a copied SfsFile is returned.
+pub fn open(self: SfsFile, alloc: std.mem.Allocator, io: Io, filepath: []const u8) !SfsFile {
+    const path = std.mem.trim(u8, filepath, "/");
+
+    const first_element: []const u8 = std.mem.sliceTo(path, '/');
+
+    const dir: Directory = try self.inode.directory(alloc, io, &self.archive.cache, self.archive.super.dir_start);
+    defer dir.deinit(alloc);
+
+    var cur_slice = dir.entries;
+    var idx: usize = undefined;
     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;
+        idx = cur_slice.len / 2;
+        switch (std.mem.order(u8, first_element, cur_slice[idx].name)) {
+            .eq => break,
+            .lt => cur_slice = cur_slice[0..idx],
+            .gt => cur_slice = cur_slice[idx..],
         }
-                defer fil.deinit();
-                return fil.open(alloc, path[idx + 1 ..]);
-            },
-            .lt => cur_slice = cur_slice[0..split],
-            .gt => cur_slice = cur_slice[split + 1 ..],
+    } else {
+        return error.NotFound;
     }
-    }
-    return FileError.NotFound;
+    if (first_element.len == path.len) return .initDirEntry(alloc, io, self.archive, cur_slice[idx]);
+    if (cur_slice[idx].type != .dir) return error.NotFound;
+    const tmp_file: SfsFile = try .initDirEntry(alloc, io, self.archive, cur_slice[idx]);
+    defer tmp_file.deinit();
+
+    return tmp_file.open(alloc, io, path[first_element.len..]);
 }
 
-pub fn isSymlink(self: SfsFile) bool {
-    return switch (self.inode.hdr.inode_type) {
-        .symlink, .ext_symlink => true,
-        else => false,
-    };
+pub fn extract(self: SfsFile, alloc: std.mem.Allocator, io: Io, ext_dir: []const u8, options: ExtractionOptions) !void {
+    _ = self;
+    _ = alloc;
+    _ = io;
+    _ = ext_dir;
+    _ = options;
+    return error.TODO;
 }
-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,
-    };
-}
-
-/// 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,
-    };
-}
-
-/// 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);
-    }
-};

src/inode.zig

@@ -1,32 +1,118 @@
-//! A file-system object. Represents a File or directory.
-
 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 Reader = Io.Reader;
 
-const Archive = @import("archive.zig");
-const DirEntry = @import("dir_entry.zig");
-const ExtractionOptions = @import("options.zig");
-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 MetadataReader = @import("util/metadata.zig");
+const DecompCache = @import("decomp_cache.zig");
+const Directory = @import("directory.zig");
+const MetadataReader = @import("meta_rdr.zig");
 
-pub const Ref = packed struct {
+const Inode = @This();
+
+hdr: Header,
+data: Data,
+
+/// Read an inode given an inode Ref.
+pub fn initRef(alloc: std.mem.Allocator, io: Io, cache: *DecompCache, inode_start: u64, block_size: u32, ref: Ref) !Inode {
+    var meta: MetadataReader = .init(io, cache, inode_start + ref.block_start);
+    defer meta.deinit(io);
+    try meta.interface.discardAll(ref.block_offset);
+
+    return .init(alloc, &meta.interface, block_size);
+}
+pub fn initDirEntry(alloc: std.mem.Allocator, io: Io, cache: *DecompCache, inode_start: u64, block_size: u32, entry: Directory.Entry) !Inode {
+    var meta: MetadataReader = .init(io, cache, inode_start + entry.block_start);
+    defer meta.deinit(io);
+    try meta.interface.discardAll(entry.block_offset);
+
+    return .init(alloc, &meta.interface, block_size);
+}
+/// Read the inode from the given Reader.
+pub fn init(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Inode {
+    var hdr: Header = undefined;
+    try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
+    const data: Data = switch (hdr.type) {
+        .dir => .{ .dir = try .init(rdr) },
+        .file => .{ .file = try .init(alloc, rdr, block_size) },
+        .symlink => .{ .symlink = try .init(alloc, rdr) },
+        .block_dev => .{ .block_dev = try .init(rdr) },
+        .char_dev => .{ .char_dev = try .init(rdr) },
+        .fifo => .{ .fifo = try .init(rdr) },
+        .socket => .{ .socket = try .init(rdr) },
+        .ext_dir => .{ .ext_dir = try .init(rdr) },
+        .ext_file => .{ .ext_file = try .init(alloc, rdr, block_size) },
+        .ext_symlink => .{ .ext_symlink = try .init(alloc, rdr) },
+        .ext_block_dev => .{ .ext_block_dev = try .init(rdr) },
+        .ext_char_dev => .{ .ext_char_dev = try .init(rdr) },
+        .ext_fifo => .{ .ext_fifo = try .init(rdr) },
+        .ext_socket => .{ .ext_socket = try .init(rdr) },
+    };
+    return .{
+        .hdr = hdr,
+        .data = data,
+    };
+}
+pub fn copy(self: Inode, alloc: std.mem.Allocator) !Inode {
+    var new_inode = self;
+    switch (new_inode.data) {
+        .file => |*f| {
+            if (f.blocks.len > 0) {
+                f.blocks = try alloc.alloc(DataBlock, f.blocks.len);
+                @memcpy(f.blocks, self.data.file.blocks);
+            }
+        },
+        .ext_file => |*f| {
+            if (f.blocks.len > 0) {
+                f.blocks = try alloc.alloc(DataBlock, f.blocks.len);
+                @memcpy(f.blocks, self.data.ext_file.blocks);
+            }
+        },
+        .symlink => |*s| {
+            s.target = try alloc.alloc(u8, s.target.len);
+            @memcpy(s.target, self.data.symlink.target);
+        },
+        .ext_symlink => |*s| {
+            s.target = try alloc.alloc(u8, s.target.len);
+            @memcpy(s.target, self.data.ext_symlink.target);
+        },
+    }
+    return new_inode;
+}
+pub fn deinit(self: Inode, alloc: std.mem.Allocator) void {
+    switch (self.data) {
+        .file => |f| f.deinit(alloc),
+        .ext_file => |f| f.deinit(alloc),
+        .symlink => |s| s.deinit(alloc),
+        .ext_symlink => |s| s.deinit(alloc),
+        else => {},
+    }
+}
+
+// Utility functions
+
+pub fn directory(self: Inode, alloc: std.mem.Allocator, io: Io, cache: *DecompCache, dir_start: u64) !Directory {
+    return switch (self.data) {
+        .dir => |d| readDirectory(alloc, io, cache, dir_start, d),
+        .ext_dir => |d| readDirectory(alloc, io, cache, dir_start, d),
+        else => error.NotDirectory,
+    };
+}
+fn readDirectory(alloc: std.mem.Allocator, io: Io, cache: *DecompCache, dir_start: u64, d: anytype) !Directory {
+    var meta: MetadataReader = .init(io, cache, dir_start + d.block_start);
+    defer meta.deinit(io);
+    try meta.interface.discardAll(d.block_offset);
+
+    return .init(alloc, &meta.interface, d.size);
+}
+
+// Types
+
+pub const Ref = packed struct(u64) {
     block_offset: u16,
     block_start: u32,
     _: u16,
 };
 
-pub const InodeType = enum(u16) {
+pub const Enum = enum(u16) {
     dir = 1,
     file,
     symlink,
@@ -43,147 +129,270 @@ pub const InodeType = enum(u16) {
     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,
+pub const Header = extern struct {
+    type: Enum,
+    permission: u16,
     uid_idx: u16,
     gid_idx: u16,
     mod_time: u32,
     num: u32,
 };
 
-const Inode = @This();
+pub const Data = union(Enum) {
+    dir: Dir,
+    file: File,
+    symlink: Symlink,
+    block_dev: Device,
+    char_dev: Device,
+    fifo: IPC,
+    socket: IPC,
+    ext_dir: ExtDir,
+    ext_file: ExtFile,
+    ext_symlink: ExtSymlink,
+    ext_block_dev: ExtDevice,
+    ext_char_dev: ExtDevice,
+    ext_fifo: ExtIPC,
+    ext_socket: ExtIPC,
+};
 
-hdr: Header,
-data: InodeData,
+pub const DataBlock = packed struct(u32) {
+    size: u24,
+    uncompressed: bool,
+    _: u7,
+};
 
-pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Inode {
-    var hdr: Header = undefined;
-    try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
+const Dir = extern struct {
+    block_start: u32,
+    hard_links: u32,
+    size: u16,
+    block_offset: u16,
+    parent: u32,
+
+    const Self = @This();
+
+    fn init(rdr: *Reader) !Self {
+        var dir: Self = undefined;
+        try rdr.readSliceEndian(Self, @ptrCast(&dir), .little);
+        return dir;
+    }
+};
+const ExtDir = extern struct {
+    hard_links: u32,
+    size: u32,
+    block_start: u32,
+    parent: u32,
+    idx_count: u16,
+    block_offset: u16,
+    xattr_idx: u32,
+    // []DirIndex
+
+    const Self = @This();
+
+    fn init(rdr: *Reader) !Self {
+        var dir: Self = undefined;
+        try rdr.readSliceEndian(Self, @ptrCast(&dir), .little);
+        return dir;
+    }
+};
+
+const File = struct {
+    data_start: u32,
+    frag_idx: u32,
+    frag_offset: u32,
+    size: u32,
+    blocks: []DataBlock,
+
+    const Raw = extern struct {
+        data_start: u32,
+        frag_idx: u32,
+        frag_offset: u32,
+        size: u32,
+    };
+
+    const Self = @This();
+
+    pub fn init(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Self {
+        var raw: Raw = undefined;
+        try rdr.readSliceEndian(Raw, @ptrCast(&raw), .little);
+
+        var blocks_num = raw.size / block_size;
+        if (raw.frag_idx == 0xFFFFFFFF and raw.size % block_size > 0)
+            blocks_num += 1;
+
+        const blocks: []DataBlock = try alloc.alloc(DataBlock, blocks_num);
+        errdefer alloc.free(blocks);
+
+        try rdr.readSliceEndian(DataBlock, blocks, .little);
         return .{
-        .hdr = hdr,
-        .data = switch (hdr.inode_type) {
-            .dir => .{ .dir = try .read(rdr) },
-            .file => .{ .file = try .read(alloc, rdr, block_size) },
-            .symlink => .{ .symlink = try .read(alloc, rdr) },
-            .block_dev => .{ .block_dev = try .read(rdr) },
-            .char_dev => .{ .char_dev = try .read(rdr) },
-            .fifo => .{ .fifo = try .read(rdr) },
-            .socket => .{ .socket = try .read(rdr) },
-            .ext_dir => .{ .ext_dir = try .read(rdr) },
-            .ext_file => .{ .ext_file = try .read(alloc, rdr, block_size) },
-            .ext_symlink => .{ .ext_symlink = try .read(alloc, rdr) },
-            .ext_block_dev => .{ .ext_block_dev = try .read(rdr) },
-            .ext_char_dev => .{ .ext_char_dev = try .read(rdr) },
-            .ext_fifo => .{ .ext_fifo = try .read(rdr) },
-            .ext_socket => .{ .ext_socket = try .read(rdr) },
-        },
+            .data_start = raw.data_start,
+            .frag_idx = raw.frag_idx,
+            .frag_offset = raw.frag_offset,
+            .size = raw.size,
+            .blocks = blocks,
         };
     }
-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: File, alloc: std.mem.Allocator) void {
+        alloc.free(self.blocks);
     }
+};
+const ExtFile = struct {
+    data_start: u64,
+    size: u64,
+    sparse: u64,
+    hard_links: u32,
+    frag_idx: u32,
+    frag_offset: u32,
+    xattr_idx: u32,
+    blocks: []DataBlock,
 
-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),
-        else => {},
-    }
-}
+    const Raw = extern struct {
+        data_start: u64,
+        size: u64,
+        sparse: u64,
+        hard_links: u32,
+        frag_idx: u32,
+        frag_offset: u32,
+        xattr_idx: u32,
+    };
 
-/// 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,
+    const Self = @This();
+
+    pub fn init(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Self {
+        var raw: Raw = undefined;
+        try rdr.readSliceEndian(Raw, @ptrCast(&raw), .little);
+
+        var blocks_num = raw.size / block_size;
+        if (raw.frag_idx == 0xFFFFFFFF and raw.size % block_size > 0)
+            blocks_num += 1;
+
+        const blocks: []DataBlock = try alloc.alloc(DataBlock, blocks_num);
+        errdefer alloc.free(blocks);
+
+        try rdr.readSliceEndian(DataBlock, blocks, .little);
+        return .{
+            .data_start = raw.data_start,
+            .size = raw.size,
+            .sparse = raw.sparse,
+            .hard_links = raw.hard_links,
+            .frag_idx = raw.frag_idx,
+            .frag_offset = raw.frag_offset,
+            .xattr_idx = raw.xattr_idx,
+            .blocks = blocks,
         };
     }
-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;
+    pub fn deinit(self: ExtFile, alloc: std.mem.Allocator) void {
+        alloc.free(self.blocks);
     }
+};
 
-/// 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,
+const Symlink = struct {
+    hard_links: u32,
+    target: []const u8,
+
+    const Raw = extern struct {
+        hard_links: u32,
+        target_size: u32,
+    };
+
+    const Self = @This();
+
+    pub fn init(alloc: std.mem.Allocator, rdr: *Reader) !Self {
+        var raw: Raw = undefined;
+        try rdr.readSliceEndian(Raw, @ptrCast(&raw), .little);
+
+        const target = try alloc.alloc(u8, raw.target_size);
+        try rdr.readSliceEndian(u8, target, .little);
+
+        return .{
+            .hard_links = raw.hard_links,
+            .target = target,
         };
     }
-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);
+    pub fn deinit(self: Symlink, alloc: std.mem.Allocator) void {
+        alloc.free(self.target);
     }
+};
+const ExtSymlink = struct {
+    hard_links: u32,
+    xattr_idx: u32,
+    target: []const u8,
 
-/// 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 {
-    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,
+    const Raw = extern struct {
+        hard_links: u32,
+        target_size: u32,
+    };
+
+    const Self = @This();
+
+    pub fn init(alloc: std.mem.Allocator, rdr: *Reader) !Self {
+        var raw: Raw = undefined;
+        try rdr.readSliceEndian(Raw, @ptrCast(&raw), .little);
+
+        const target = try alloc.alloc(u8, raw.target_size);
+        errdefer alloc.free(target);
+        try rdr.readSliceEndian(u8, target, .little);
+
+        var xattr_idx: u32 = undefined;
+        try rdr.readSliceEndian(u32, @ptrCast(&xattr_idx), .little);
+
+        return .{
+            .hard_links = raw.hard_links,
+            .target = target,
+            .xattr_idx = xattr_idx,
         };
     }
 
-/// 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));
-    }
-    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;
-            }
-        }
-    }
+    pub fn deinit(self: ExtSymlink, alloc: std.mem.Allocator) void {
+        alloc.free(self.target);
     }
+};
 
-/// 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);
+const Device = extern struct {
+    hard_links: u32,
+    device: u32,
+
+    const Self = @This();
+
+    fn init(rdr: *Reader) !Self {
+        var dir: Self = undefined;
+        try rdr.readSliceEndian(Self, @ptrCast(&dir), .little);
+        return dir;
     }
+};
+const ExtDevice = extern struct {
+    hard_links: u32,
+    device: u32,
+    xattr_idx: u32,
+
+    const Self = @This();
+
+    fn init(rdr: *Reader) !Self {
+        var dir: Self = undefined;
+        try rdr.readSliceEndian(Self, @ptrCast(&dir), .little);
+        return dir;
+    }
+};
+
+const IPC = extern struct {
+    hard_links: u32,
+
+    const Self = @This();
+
+    fn init(rdr: *Reader) !Self {
+        var dir: Self = undefined;
+        try rdr.readSliceEndian(Self, @ptrCast(&dir), .little);
+        return dir;
+    }
+};
+const ExtIPC = extern struct {
+    hard_links: u32,
+    xattr_idx: u32,
+
+    const Self = @This();
+
+    fn init(rdr: *Reader) !Self {
+        var dir: Self = undefined;
+        try rdr.readSliceEndian(Self, @ptrCast(&dir), .little);
+        return dir;
+    }
+};

src/inode_data/dir.zig

@@ -1,32 +0,0 @@
-const Reader = @import("std").Io.Reader;
-
-pub const Dir = packed struct {
-    block_start: u32,
-    hard_links: u32,
-    size: u16,
-    block_offset: u16,
-    parent_num: u32,
-
-    pub fn read(rdr: *Reader) !Dir {
-        var d: Dir = undefined;
-        try rdr.readSliceEndian(Dir, @ptrCast(&d), .little);
-        return d;
-    }
-};
-
-pub const ExtDir = packed struct {
-    hard_links: u32,
-    size: u32,
-    block_start: u32,
-    parent_num: u32,
-    idx_count: u16,
-    block_offset: u16,
-    xattr_id: u32,
-    // index: []DirIndex
-
-    pub fn read(rdr: *Reader) !ExtDir {
-        var d: ExtDir = undefined;
-        try rdr.readSliceEndian(Dir, @ptrCast(&d), .little);
-        return d;
-    }
-};

src/inode_data/file.zig

@@ -1,76 +0,0 @@
-const std = @import("std");
-const Reader = std.Io.Reader;
-
-pub const BlockSize = packed struct {
-    size: u24,
-    uncompressed: bool,
-    _: u7,
-};
-
-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_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;
-        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_sizes = sizes,
-        };
-    }
-
-    pub fn deinit(self: File, alloc: std.mem.Allocator) void {
-        alloc.free(self.block_sizes);
-    }
-};
-
-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_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;
-        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_sizes = sizes,
-        };
-    }
-
-    pub fn deinit(self: ExtFile, alloc: std.mem.Allocator) void {
-        alloc.free(self.block_sizes);
-    }
-};

src/inode_data/misc.zig

@@ -1,98 +0,0 @@
-const std = @import("std");
-const Reader = std.Io.Reader;
-
-pub const Symlink = struct {
-    hard_links: u32,
-    target: []const u8,
-
-    pub fn read(alloc: std.mem.Allocator, rdr: *Reader) !Symlink {
-        var start: [8]u8 = undefined;
-        try rdr.readSliceAll(&start);
-        const target_size = std.mem.readInt(u32, start[4..8], .little);
-        const target = try alloc.alloc(u8, target_size + 1);
-        errdefer alloc.free(target);
-        try rdr.readSliceEndian(u8, target, .little);
-        return .{
-            .hard_links = std.mem.readInt(u32, start[0..4], .little),
-            .target = target,
-        };
-    }
-
-    pub fn deinit(self: Symlink, alloc: std.mem.Allocator) void {
-        alloc.free(self.target);
-    }
-};
-
-pub const ExtSymlink = struct {
-    hard_links: u32,
-    target: []const u8,
-    xattr_idx: u32,
-
-    pub fn read(alloc: std.mem.Allocator, rdr: *Reader) !ExtSymlink {
-        var start: [8]u8 = undefined;
-        try rdr.readSliceAll(&start);
-        const target_size = std.mem.readInt(u32, start[4..8], .little);
-        const target = try alloc.alloc(u8, target_size + 1);
-        errdefer alloc.free(target);
-        try rdr.readSliceEndian(u8, target, .little);
-        var xattr_idx: u32 = undefined;
-        try rdr.readSliceEndian(u32, @ptrCast(&xattr_idx), .little);
-        return .{
-            .hard_links = std.mem.readInt(u32, start[0..4], .little),
-            .target = target,
-            .xattr_idx = xattr_idx,
-        };
-    }
-
-    pub fn deinit(self: ExtSymlink, alloc: std.mem.Allocator) void {
-        alloc.free(self.target);
-    }
-};
-
-/// A block or character device.
-pub const Dev = packed struct {
-    hard_links: u32,
-    dev: u32,
-
-    pub fn read(rdr: *Reader) !Dev {
-        var d: Dev = undefined;
-        try rdr.readSliceEndian(Dev, @ptrCast(&d), .little);
-        return d;
-    }
-};
-
-/// An extended block or character device.
-pub const ExtDev = packed struct {
-    hard_links: u32,
-    dev: u32,
-    xattr_idx: u32,
-
-    pub fn read(rdr: *Reader) !ExtDev {
-        var d: ExtDev = undefined;
-        try rdr.readSliceEndian(ExtDev, @ptrCast(&d), .little);
-        return d;
-    }
-};
-
-/// A socket or FIFO file.
-pub const IPC = packed struct {
-    hard_links: u32,
-
-    pub fn read(rdr: *Reader) !IPC {
-        var d: IPC = undefined;
-        try rdr.readSliceEndian(IPC, @ptrCast(&d), .little);
-        return d;
-    }
-};
-
-/// An extended socket or FIFO file.
-pub const ExtIPC = packed struct {
-    hard_links: u32,
-    xattr_idx: u32,
-
-    pub fn read(rdr: *Reader) !ExtIPC {
-        var d: ExtIPC = undefined;
-        try rdr.readSliceEndian(ExtIPC, @ptrCast(&d), .little);
-        return d;
-    }
-};

src/lookup.zig

@@ -0,0 +1,104 @@
+const std = @import("std");
+const Io = std.Io;
+
+const DecompCache = @import("decomp_cache.zig");
+const MetadataReader = @import("meta_rdr.zig");
+
+pub fn stateless(comptime T: anytype, io: Io, cache: *DecompCache, table_start: u64, idx: u32) !T {
+    const PER_BLOCK = 8192 / @sizeOf(T);
+
+    const block = idx / PER_BLOCK;
+    const block_idx = idx % PER_BLOCK;
+
+    const offset_offset = table_start + (block * 8);
+    const offset: u64 = std.mem.readInt(u64, cache.map.memory[offset_offset..][0..2], .little);
+
+    var meta: MetadataReader = .init(io, cache, offset);
+    defer meta.deinit(io);
+    try meta.discardAll(block_idx * @sizeOf(T));
+
+    var new: T = undefined;
+    try meta.interface.readSliceEndian(T, @ptrCast(&new), .little);
+    return new;
+}
+
+pub fn Table(comptime T: anytype) type {
+    return struct {
+        const PER_BLOCK = 8192 / @sizeOf(T);
+
+        const Table = @This();
+
+        alloc: std.mem.Allocator,
+
+        cache: *DecompCache,
+        table_start: u64,
+
+        num: u32,
+        values: std.AutoHashMap(u32, []T),
+        mut: Io.RwLock,
+
+        pub fn init(alloc: std.mem.Allocator, cache: *DecompCache, table_start: u64, num_values: u32) Table {
+            return .{
+                .alloc = alloc,
+
+                .cache = cache,
+                .table_start = table_start,
+
+                .num = num_values,
+                .values = .init(alloc),
+            };
+        }
+        pub fn deinit(self: *Table) void {
+            var iter = self.values.valueIterator();
+            while (iter.next()) |v|
+                self.alloc.free(v);
+            self.values.deinit();
+        }
+
+        pub fn get(self: *Table, io: Io, idx: u32) Error!T {
+            const block = idx / PER_BLOCK;
+            const block_idx = idx % PER_BLOCK;
+            {
+                try self.mut.lockShared(io);
+                defer self.mut.unlockShared(io);
+
+                const val = self.values.get(block);
+                if (val != null) return val.*[block_idx];
+            }
+            try self.mut.lock(io);
+            defer self.mut.unlock(io);
+
+            const val = try self.values.getOrPut(block);
+            if (val.found_existing)
+                return val.value_ptr.*[block_idx];
+            errdefer self.values.removeByPtr(val.key_ptr);
+
+            const offset_offset = self.table_start + (block * 8);
+            const offset: u64 = std.mem.readInt(u64, self.cache.map.memory[offset_offset..][0..2], .little);
+
+            var meta: MetadataReader = .init(io, self.cache, offset);
+            defer meta.deinit(io);
+
+            const size = if (block == ((self.num - 1) / PER_BLOCK))
+                self.num % PER_BLOCK
+            else
+                PER_BLOCK;
+
+            const new_block = try self.alloc.alloc(T, size);
+            errdefer self.alloc.free(new_block);
+            try meta.interface.readSliceEndian(T, new_block, .little);
+
+            val.value_ptr.* = new_block;
+
+            return new_block[block_idx];
+        }
+    };
+}
+
+// Types
+
+pub const Error = error{} || std.mem.Allocator.Error;
+
+pub const FragmentEntry = extern struct {};
+
+pub const XattrEntry = extern struct {};

src/meta_rdr.zig

@@ -0,0 +1,109 @@
+const std = @import("std");
+const Io = std.Io;
+const Reader = Io.Reader;
+const Writer = Io.Writer;
+const Limit = Io.Limit;
+
+const DecompCache = @import("decomp_cache.zig");
+
+const MetadataReader = @This();
+
+io: Io,
+cache: *DecompCache,
+
+cur_offset: u64 = 0,
+next_offset: u64,
+
+interface: Reader = .{
+    .buffer = &[0]u8{},
+    .end = 0,
+    .seek = 0,
+    .vtable = &.{
+        .stream = stream,
+        .discard = discard,
+        .readVec = readVec,
+    },
+},
+
+pub fn init(io: Io, cache: *DecompCache, start: u64) MetadataReader {
+    return .{
+        .io = io,
+        .cache = cache,
+
+        .next_offset = start,
+    };
+}
+pub fn deinit(self: *MetadataReader, io: Io) void {
+    self.cache.finished(io, self.cur_offset);
+}
+
+fn advance(self: *MetadataReader) !void {
+    self.cache.finished(self.io, self.cur_offset);
+
+    self.interface.seek = 0;
+    errdefer self.interface.end = 0;
+
+    const hdr: Header = @bitCast(std.mem.readInt(u16, self.cache.map.memory[self.next_offset..][0..2], .little));
+    self.cur_offset = self.next_offset + 2;
+    self.next_offset = self.cur_offset + hdr.size;
+
+    if (hdr.uncompressed) {
+        self.interface.buffer = self.cache.map.memory[self.cur_offset..][0..hdr.size];
+        self.interface.end = hdr.size;
+        return;
+    }
+    self.interface.buffer = try self.cache.get(self.io, self.cur_offset, hdr.size, 8192);
+    self.interface.end = self.interface.buffer.len;
+}
+
+fn stream(r: *Reader, w: *Writer, limit: Limit) Reader.StreamError!usize {
+    if (r.seek >= r.end) {
+        const self: *MetadataReader = @fieldParentPtr("interface", r);
+        self.advance() catch |err| {
+            std.debug.print("error advancing metadata reader: {}\n", .{err});
+            return Reader.Error.ReadFailed;
+        };
+    }
+    const to_write = @min(r.end - r.seek, @intFromEnum(limit));
+    const wrote = try w.write(r.buffer[r.seek..][0..to_write]);
+    r.seek += wrote;
+    return wrote;
+}
+fn discard(r: *Reader, limit: Limit) Reader.Error!usize {
+    if (r.seek >= r.end) {
+        const self: *MetadataReader = @fieldParentPtr("interface", r);
+        self.advance() catch |err| {
+            std.debug.print("error advancing metadata reader: {}\n", .{err});
+            return Reader.Error.ReadFailed;
+        };
+    }
+    const to_discard = @min(r.end - r.seek, @intFromEnum(limit));
+    r.seek += to_discard;
+    return to_discard;
+}
+fn readVec(r: *Reader, vec: [][]u8) Reader.Error!usize {
+    if (r.seek >= r.end) {
+        const self: *MetadataReader = @fieldParentPtr("interface", r);
+        self.advance() catch |err| {
+            std.debug.print("error advancing metadata reader: {}\n", .{err});
+            return Reader.Error.ReadFailed;
+        };
+    }
+    var total: usize = 0;
+    for (vec) |v| {
+        const to_copy = @min(r.end - r.seek, v.len);
+        @memcpy(v[0..to_copy], r.buffer[r.seek..][0..to_copy]);
+        r.seek += to_copy;
+        total += to_copy;
+        if (r.seek >= r.end)
+            break;
+    }
+    return total;
+}
+
+// Types
+
+const Header = packed struct(u16) {
+    size: u15,
+    uncompressed: bool,
+};

src/options.zig

@@ -5,8 +5,6 @@ const Writer = std.Io.Writer;
 
 const ExtractionOptions = @This();
 
-/// The number of threads used for extraction. 0 implies single threaded.
-threads: usize = 1,
 /// 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.
@@ -18,16 +16,10 @@ verbose: bool = false,
 /// Where to print verbose log.
 verbose_writer: ?*Writer = null,
 
-pub const SingleThreadedDefault: ExtractionOptions = .{};
-pub fn Default() !ExtractionOptions {
-    return .{
-        .threads = try std.Thread.getCpuCount(),
-    };
-}
+pub const default: ExtractionOptions = .{};
 pub fn VerboseDefault(wrt: *Writer) !ExtractionOptions {
     return .{
         .verbose = true,
         .verbose_writer = wrt,
-        .threads = try std.Thread.getCpuCount(),
     };
 }

src/root.zig

@@ -1,2 +1,8 @@
 pub const Archive = @import("archive.zig");
 pub const ExtractionOptions = @import("options.zig");
+
+test {
+    const std = @import("std");
+
+    std.testing.refAllDecls(Archive);
+}

src/super.zig

@@ -1,63 +0,0 @@
-const std = @import("std");
-const math = std.math;
-
-const CompressionType = @import("decomp.zig").CompressionType;
-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: CompressionType,
-    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

@@ -1,108 +0,0 @@
-const std = @import("std");
-const Mutex = std.Thread.Mutex;
-
-const Archive = @import("archive.zig");
-const DecompFn = @import("decomp.zig").DecompFn;
-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/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_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/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

@@ -1,97 +0,0 @@
-const std = @import("std");
-const Reader = std.Io.Reader;
-const Writer = std.Io.Writer;
-const Limit = std.Io.Limit;
-const StreamError = std.Io.Reader.StreamError;
-
-const DecompFn = @import("../decomp.zig").DecompFn;
-
-const BlockHeader = packed struct {
-    size: u15,
-    uncompressed: bool,
-};
-
-const This = @This();
-
-alloc: std.mem.Allocator,
-rdr: *Reader,
-decomp: DecompFn,
-
-buf: [8192]u8 = undefined,
-
-interface: Reader,
-err: ?anyerror = null,
-
-pub fn init(alloc: std.mem.Allocator, rdr: *Reader, decomp: DecompFn) This {
-    return .{
-        .alloc = alloc,
-        .rdr = rdr,
-        .decomp = decomp,
-        .interface = .{
-            .buffer = &[0]u8{},
-            .end = 0,
-            .seek = 0,
-            .vtable = &.{
-                .stream = stream,
-                .discard = discard,
-                .readVec = readVec,
-            },
-        },
-    };
-}
-
-fn advance(self: *This) !void {
-    self.interface.seek = 0;
-    var hdr: BlockHeader = undefined;
-    try self.rdr.readSliceEndian(BlockHeader, @ptrCast(&hdr), .little);
-    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;
-    }
-    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 {
-    const self: *This = @fieldParentPtr("interface", rdr);
-    if (rdr.end == rdr.seek) self.advance() catch |err| {
-        self.err = err;
-        return StreamError.ReadFailed;
-    };
-    if (@intFromEnum(limit) == 0) return 0;
-    const to_write = @min(rdr.end - rdr.seek, @intFromEnum(limit));
-    const wrote = try wrt.write(self.buf[rdr.seek .. rdr.seek + to_write]);
-    self.interface.seek += wrote;
-    return wrote;
-}
-fn discard(rdr: *Reader, limit: Limit) error{ EndOfStream, ReadFailed }!usize {
-    const self: *This = @fieldParentPtr("interface", rdr);
-    if (rdr.end == rdr.seek) self.advance() catch |err| {
-        self.err = err;
-        return StreamError.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 {
-    const self: *This = @fieldParentPtr("interface", rdr);
-    if (rdr.end == rdr.seek) self.advance() catch |err| {
-        self.err = err;
-        return StreamError.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], self.buf[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/offset_file.zig

@@ -1,20 +0,0 @@
-//! 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 OffsetFile = @This();
-
-fil: File,
-offset: u64,
-
-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);
-    try rdr.seekTo(self.offset + offset);
-    return rdr;
-}

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/zig_decomp.zig

@@ -0,0 +1,40 @@
+const std = @import("std");
+const Reader = std.Io.Reader;
+const flate = std.compress.flate;
+const zstd = std.compress.zstd;
+const xz = std.compress.xz;
+const lzma = std.compress.lzma;
+
+const Error = @import("decomp.zig").Error;
+
+pub fn zlibDecompress(_: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var buf: [flate.max_window_len]u8 = undefined;
+
+    var rdr: Reader = .fixed(in);
+    var decomp: flate.Decompress = .init(&rdr, .zlib, &buf);
+
+    return decomp.reader.readSliceShort(out);
+}
+pub fn zstdDecompress(alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    const buf = try alloc.alloc(u8, in.len + zstd.block_size_max);
+    defer alloc.free(buf);
+
+    var rdr: Reader = .fixed(in);
+    var decomp: zstd.Decompress = .init(&rdr, buf, .{ .window_len = in.len });
+
+    return decomp.reader.readSliceShort(out);
+}
+pub fn lzmaDecompress(alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var rdr: Reader = .fixed(in);
+    var decomp: lzma.Decompress = .initOptions(&rdr, alloc, &[0]u8{}, .{}, 2 * out.len);
+    defer decomp.deinit();
+
+    return decomp.reader.readSliceShort(out);
+}
+pub fn xzDecompress(alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var rdr: Reader = .fixed(in);
+    var decomp: xz.Decompress = .init(&rdr, alloc, &[0]u8{});
+    defer decomp.deinit();
+
+    return decomp.reader.readSliceShort(out);
+}