Fixed some issues with stateless Lookup Table

It works, but is very slow.

.github/workflows/release-build.yml

@@ -0,0 +1,31 @@
+name: Release Build
+
+on:
+  push:
+    tags:
+      - "v*.*.*"
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+      - uses: mlugg/setup-zig@v2
+      - name: Install deps
+        run: sudo apt update && sudo apt install -y liblzma-dev liblzo2-dev
+      - name: Build normal version
+        run: zig build --release=fast -Duse_zig_decomp=true -Dversion=${{ github.ref_name }}
+      - name: Move zig build out
+        run: mv zig-out/bin/unsquashfs ./unsquashfs-x86_64-zig-libs
+      - name: Rebuild with C libraries
+        run: zig build --release=fast -Dversion="${{ github.ref_name }}"
+      - name: Move C build out
+        run: mv zig-out/bin/unsquashfs ./unsquashfs-x86_64-c-libs
+      - name: Release
+        uses: softprops/action-gh-release@v2
+        with:
+          prerelease: true
+          files: |
+            unsquashfs-x86_64-zig-libs
+            unsquashfs-x86_64-c-libs

.gitignore

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

.zed/debug.json

@@ -0,0 +1,25 @@
+// Project-local debug tasks
+//
+// For more documentation on how to configure debug tasks,
+// see: https://zed.dev/docs/debugger
+[
+	{
+		"label": "Build & Run",
+
+		"adapter": "CodeLLDB",
+		"request": "launch",
+
+		"build": {
+			"command": "zig",
+			"args": ["build", "-Ddebug=true"],
+		},
+
+		"program": "zig-out/bin/unsquashfs",
+		"args": [
+			"--force",
+			"-d",
+			"testing/TestExtractUnsquashfs",
+			"testing/LinuxPATest.sfs",
+		],
+	},
+]

LICENSE

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2025 Caleb Gardner
+Copyright (c) 2026 Caleb Gardner
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

README.md

@@ -1,7 +1,75 @@
 # zig-squashfs
 
-Messing around with zig via making a squashfs library. May amount to something. Or not.
+This is my experiments to learn Zig. Might amount to something. Might not.
 
-## Current state
+A library and application to decompress or view squashfs archives.
 
-Performance is reatively bad (when compared to the official [squashfs-tools](https://github.com/plougher/squashfs-tools), but the basics should fully work.
+## Current State
+
+Overall works, but currently is missing some features ([see below](#capabilities)) and has significantly slow performance compared to `unsquashfs` ([see below](#performance)).
+
+## Build options
+
+> `-Duse_c_libs=true`
+
+Instead of using Zig's standard library for decompression, use the system's C libraries. Has the benefit of being much faster and enabling LZO and LZ4 decompression.
+
+> `-Dallow_lzo=true`
+
+Enable compiling with LZO decompression support. The LZO library currently has some issues with Zig when imported so it's easier to just disable it by default. Only has an effect when using `-Duse_c_libs=true`.
+
+> `-Ddebug=true`
+
+Sets various build options that make debugging easier. Specifically, debug optimization is forced, valgrind support is enabled, error tracing is enabled, stipping is disabled, and copmilation uses LLVM (this is due to some linking issues when on Debug optimization and is required for debugging tools such as `lldb`. In the future this may be removed from the debug flag).
+
+> `-Dversion=0.0.0`
+
+Sets the version of `unsquashfs` shown when `--version` is passed.
+
+## Capabilities
+
+Most features are present except for the following:
+
+* When using Zig decompression libraries then lzo and lz4 compression types are unavailable. I don't _currently_ plan on spending the time to find and validate a library since neither is popular.
+* When using C decompression libraries, lzo is not supported by default due to [some issues](#build-considerations). If it's needed it's trivial to fix, but it's easiest to just leave it disabled.
+
+## Performance
+
+This is some basic observation's I've made about this library's performance when compared to `unsquashfs`. Unless otherwise stated, most observations were made when extracting my test archive (which is fairly small and uses zstd compression) and with `--release=fast`.
+
+Currently, my only performance checks are checking execution time, nothing deeper.
+
+* Under ideal circumstances, my library is ~70% slower (.12s vs .20s).
+* Using Zig decompression libraries *significantly* increases decompression time by ~600%. Under ideal circumstances.
+* Performance improvements/regressions will be common. I'm still learning Zig.
+
+Example Times:
+
+* *unsquashfs, multi-threaded*: .12s
+* *unsquashfs, single-threaded*: .13s
+* *C-libs, single-threaded*: .45s
+* *C-libs, multi-threaded*: .20s
+* *Zig-libs, single-threaded*: 5.78s
+* *Zig-libs, multi-threaded*: 1.08s
+
+## Build considerations
+
+Compilation without `use_c_libs` works completely fine, but Zig has issues with some symbols from the lzo library that needs to be manually fixed. In particular you need to fix the definitions for `lzo_bytep` and `lzo_voidp` to be `*u8` and `?*anyopaque` respectively. Due to this, you have to manually enable LZO decompression using `-Dallow_lzo=true` when building.
+
+```zig
+pub const lzo_bytep = @compileError("unable to translate C expr: unexpected token ''");
+// /usr/include/lzo/lzoconf.h:148:9
+pub const lzo_charp = @compileError("unable to translate C expr: unexpected token ''");
+// /usr/include/lzo/lzoconf.h:149:9
+pub const lzo_voidp = @compileError("unable to translate C expr: unexpected token ''");
+```
+
+to
+
+```zig
+pub const lzo_bytep = *u8;
+// /usr/include/lzo/lzoconf.h:148:9
+pub const lzo_charp = @compileError("unable to translate C expr: unexpected token ''");
+// /usr/include/lzo/lzoconf.h:149:9
+pub const lzo_voidp = ?*anyopaque;
+```

build.zig

@@ -1,53 +1,76 @@
 const std = @import("std");
 
-/// version if version isn't provided during build
-const def_version = "0.0.0+testing";
-
 pub fn build(b: *std.Build) !void {
-    const opt = b.addOptions();
-    const ver = b.option([]const u8, "version", "sematic version") orelse def_version;
-    const sem_ver = try std.SemanticVersion.parse(ver);
-    opt.addOption(std.SemanticVersion, "version", sem_ver);
+    // const use_zig_decomp = b.option(bool, "use_zig_decomp", "Use zig standard library for decompression.") orelse false;
+    // const allow_lzo = b.option(bool, "allow_lzo", "Compile with lzo support") orelse false;
+    const debug = b.option(bool, "debug", "Enable options to make debugging easier.");
+    const version_string_option = b.option([]const u8, "version", "Version of the library/binary");
+
+    // const zig_squashfs_options = b.addOptions();
+    // zig_squashfs_options.addOption(bool, "use_zig_decomp", use_zig_decomp);
+    // zig_squashfs_options.addOption(bool, "allow_lzo", allow_lzo);
+
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
-    const lib_mod = b.createModule(.{
-        .root_source_file = b.path("src/root.zig"),
-        .target = target,
-        .optimize = optimize,
-    });
+
     const lib = b.addLibrary(.{
-        .linkage = .static,
-        .name = "zig_squashfs",
-        .root_module = lib_mod,
-        .version = sem_ver,
+        .name = "squashfs",
+        .root_module = b.createModule(.{
+            .optimize = if (debug == true) .Debug else optimize,
+            .target = target,
+            .valgrind = debug,
+            .root_source_file = b.path("src/root.zig"),
+        }),
+        .use_llvm = debug,
     });
 
-    const exe_mod = b.createModule(.{
-        .root_source_file = b.path("src/bin/unsquashfs.zig"),
-        .target = target,
-        .optimize = optimize,
-    });
-    exe_mod.addImport("squashfs", lib_mod);
-    exe_mod.addOptions("config", opt);
+    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),
+    );
     const exe = b.addExecutable(.{
-        .linkage = .static,
         .name = "unsquashfs",
-        .root_module = exe_mod,
-        .version = sem_ver,
+        .root_module = b.createModule(.{
+            .optimize = if (debug == true) .Debug else optimize,
+            .target = target,
+            .valgrind = debug,
+            .root_source_file = b.path("src/bin/unsquashfs.zig"),
+            .imports = &.{
+                .{ .name = "zig_squashfs", .module = lib.root_module },
+            },
+        }),
+        .use_llvm = debug,
     });
+    exe.root_module.addOptions("config", unsquashfs_options);
 
     b.installArtifact(lib);
     b.installArtifact(exe);
 
-    const lib_unit_tests = b.addTest(.{
-        .root_module = lib_mod,
+    const mod_tests = b.addTest(.{
+        .root_module = b.createModule(.{
+            .optimize = optimize,
+            .target = target,
+            .root_source_file = b.path("src/test.zig"),
+        }),
     });
-    const exe_unit_test = b.addTest(.{
-        .root_module = exe_mod,
+    const run_mod_tests = b.addRunArtifact(mod_tests);
+    const test_step = b.step("test", "Run tests");
+    test_step.dependOn(&run_mod_tests.step);
+
+    // zls build check steps
+    const lib_check = b.addLibrary(.{
+        .name = "squashfs",
+        .root_module = exe.root_module,
     });
-    const run_lib_unit_tests = b.addRunArtifact(lib_unit_tests);
-    const run_exe_unit_tests = b.addRunArtifact(exe_unit_test);
-    const test_step = b.step("test", "Run unit tests");
-    test_step.dependOn(&run_lib_unit_tests.step);
-    test_step.dependOn(&run_exe_unit_tests.step);
+    const exe_check = b.addExecutable(.{
+        .name = "unsquashfs",
+        .root_module = lib.root_module,
+    });
+    const check = b.step("check", "Check if unsquashfs compiles");
+    check.dependOn(&lib_check.step);
+    check.dependOn(&exe_check.step);
 }

build.zig.zon

@@ -1,55 +1,26 @@
 .{
-    .name = .zig_squashfs,
-    .version = "0.0.1",
-    .fingerprint = 0x527960c72c03ffe3, // Changing this has security and trust implications.
-
-    .minimum_zig_version = "0.14.0",
-
-    // This field is optional.
-    // Each dependency must either provide a `url` and `hash`, or a `path`.
-    // `zig build --fetch` can be used to fetch all dependencies of a package, recursively.
-    // Once all dependencies are fetched, `zig build` no longer requires
-    // internet connectivity.
+    .name = .squashfs,
+    .version = "0.0.6",
+    .fingerprint = 0x37ba29474b87f145, // Changing this has security and trust implications.
+    .minimum_zig_version = "0.15.2",
     .dependencies = .{
-        // See `zig fetch --save <url>` for a command-line interface for adding dependencies.
-        //.example = .{
-        //    // When updating this field to a new URL, be sure to delete the corresponding
-        //    // `hash`, otherwise you are communicating that you expect to find the old hash at
-        //    // the new URL. If the contents of a URL change this will result in a hash mismatch
-        //    // which will prevent zig from using it.
-        //    .url = "https://example.com/foo.tar.gz",
-        //
-        //    // This is computed from the file contents of the directory of files that is
-        //    // obtained after fetching `url` and applying the inclusion rules given by
-        //    // `paths`.
-        //    //
-        //    // This field is the source of truth; packages do not come from a `url`; they
-        //    // come from a `hash`. `url` is just one of many possible mirrors for how to
-        //    // obtain a package matching this `hash`.
-        //    //
-        //    // Uses the [multihash](https://multiformats.io/multihash/) format.
-        //    .hash = "...",
-        //
-        //    // When this is provided, the package is found in a directory relative to the
-        //    // build root. In this case the package's hash is irrelevant and therefore not
-        //    // computed. This field and `url` are mutually exclusive.
-        //    .path = "foo",
-        //
-        //    // When this is set to `true`, a package is declared to be lazily
-        //    // fetched. This makes the dependency only get fetched if it is
-        //    // actually used.
-        //    .lazy = false,
-        //},
+        .zlib_ng = .{
+            .url = "git+https://github.com/CalebQ42/zig-zlib-ng#5f2f02dfb28acca2517dacbbd09e9b987f57b133",
+            .hash = "zlib_ng-2.3.3-pre1-2HYS4ClFAABW8KlHMyBHtlNKE3V7kCS8wqfxawG7xeaa",
+        },
+        .zstd = .{
+            .url = "git+https://github.com/allyourcodebase/zstd.git?ref=1.5.7-1#e1a501be57f42c541e8a5597e4b59a074dfd09a3",
+            .hash = "zstd-1.5.7-1-KEItkAMwAAD6OKY3m0OOmXG7aL-aLUfrDqbP5J5oYapU",
+        },
+        .lz4 = .{
+            .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",
+        },
     },
-
-    // Specifies the set of files and directories that are included in this package.
-    // Only files and directories listed here are included in the `hash` that
-    // is computed for this package. Only files listed here will remain on disk
-    // when using the zig package manager. As a rule of thumb, one should list
-    // files required for compilation plus any license(s).
-    // Paths are relative to the build root. Use the empty string (`""`) to refer to
-    // the build root itself.
-    // A directory listed here means that all files within, recursively, are included.
     .paths = .{
         "build.zig",
         "build.zig.zon",

run_tests.sh

@@ -0,0 +1,10 @@
+#!/bin/sh
+
+zig test \
+	-lc \
+	-lz \
+	-llzma \
+	-lminilzo \
+	-llz4 \
+	-lzstd \
+		src/test.zig

src/archive.zig

@@ -0,0 +1,178 @@
+const std = @import("std");
+const Io = std.Io;
+
+const ExtractionOptions = @import("options.zig");
+const File = @import("file.zig");
+const Inode = @import("inode.zig");
+const LookupTable = @import("lookup_table.zig");
+const Decompressor = @import("util/decompressor.zig");
+const MetadataReader = @import("util/metadata.zig");
+const Utils = @import("util/misc.zig");
+const OffsetFile = @import("util/offset_file.zig");
+
+const Archive = @This();
+
+file: OffsetFile,
+super: Superblock,
+
+stateless_decomp: Decompressor,
+
+pub fn init(io: Io, file: std.Io.File, offset: u64) !Archive {
+    var rdr = file.reader(io, &[0]u8{});
+    try rdr.seekTo(offset);
+    var super: Superblock = undefined;
+    try rdr.interface.readSliceEndian(Superblock, @ptrCast(&super), .little);
+    return .{
+        .file = .init(file, offset),
+        .super = super,
+
+        .stateless_decomp = switch (super.compression) {
+            .gzip => @import("decomp/zlib.zig").stateless_decompressor,
+            .lzma => @import("decomp/lzma.zig").stateless_decompressor,
+            .lzo => return error.LzoUnsupported,
+            .xz => @import("decomp/xz.zig").stateless_decompressor,
+            .lz4 => return error.Lz4Unsupported,
+            .zstd => @import("decomp/zstd.zig").stateless_decompressor,
+        },
+    };
+}
+
+/// The root folder of the Archive. Used to open other Files.
+pub fn root(self: Archive, alloc: std.mem.Allocator, io: Io) !File {
+    const root_inode = try Utils.inodeFromRef(
+        alloc,
+        io,
+        self.file,
+        &self.stateless_decomp,
+        self.super.inode_start,
+        self.super.block_size,
+        self.super.root_ref,
+    );
+    return .init(alloc, self, root_inode, "");
+}
+/// Opens a File within the archive.
+pub fn open(self: Archive, alloc: std.mem.Allocator, io: Io, filepath: []const u8) !File {
+    const root_file = try self.root(alloc, io);
+    const path = std.mem.trim(u8, filepath, "/");
+    if (Utils.pathIsSelf(path))
+        return root_file;
+    defer root_file.deinit();
+    return root_file.open(alloc, io, filepath);
+}
+/// Extract the entire archive contents to the given directory.
+pub fn extract(self: Archive, alloc: std.mem.Allocator, io: Io, extract_dir: []const u8, options: ExtractionOptions) !void {
+    const root_inode = try Utils.inodeFromRef(
+        alloc,
+        io,
+        self.file,
+        &self.stateless_decomp,
+        self.super.inode_start,
+        self.super.block_size,
+        self.super.root_ref,
+    );
+    return root_inode.extract(alloc, io, self.file, self.super, extract_dir, options);
+}
+
+/// Returns the inode with the given inode number.
+/// Requires that the archive is exportable (has an export lookup table).
+pub fn inode(self: Archive, alloc: std.mem.Allocator, io: Io, num: u32) !Inode {
+    if (!self.super.flags.exportable)
+        return error.NotExportable;
+    const ref = try LookupTable.lookupValue(
+        Inode.Ref,
+        alloc,
+        io,
+        &self.stateless_decomp,
+        self.file,
+        self.super.export_start,
+        num + 1,
+    );
+    return Utils.inodeFromRef(
+        alloc,
+        io,
+        self.file,
+        &self.stateless_decomp,
+        self.super.inode_start,
+        self.super.block_size,
+        ref,
+    );
+}
+/// Returns a value at the given index from the Archive's id (uid/gid) table.
+pub fn idTable(self: Archive, alloc: std.mem.Allocator, io: Io, idx: u32) !u16 {
+    return LookupTable.lookupValue(
+        u16,
+        alloc,
+        io,
+        &self.stateless_decomp,
+        self.file,
+        self.super.id_start,
+        idx,
+    );
+}
+
+// Superblock
+
+const SQUASHFS_MAGIC: u32 = std.mem.readInt(u32, "hsqs", .little);
+
+const SuperblockError = error{
+    InvalidMagic,
+    InvalidBlockLog,
+    InvalidVersion,
+    InvalidCheck,
+};
+
+/// A squashfs Superblock
+pub const Superblock = extern struct {
+    magic: u32,
+    inode_count: u32,
+    mod_time: u32,
+    block_size: u32,
+    frag_count: u32,
+    compression: enum(u16) {
+        gzip = 1,
+        lzma,
+        lzo,
+        xz,
+        lz4,
+        zstd,
+    },
+    block_log: u16,
+    flags: packed struct(u16) {
+        inode_uncompressed: bool,
+        data_uncompressed: bool,
+        check: bool,
+        frag_uncompressed: bool,
+        fragment_never: bool,
+        fragment_always: bool,
+        duplicates: bool,
+        exportable: bool,
+        xattr_uncompressed: bool,
+        xattr_never: bool,
+        compression_options: bool,
+        ids_uncompressed: bool,
+        _: u4,
+    },
+    id_count: u16,
+    ver_maj: u16,
+    ver_min: u16,
+    root_ref: Inode.Ref,
+    size: u64,
+    id_start: u64,
+    xattr_start: u64,
+    inode_start: u64,
+    dir_start: u64,
+    frag_start: u64,
+    export_start: u64,
+
+    /// Validate the Superblock. If an error is returned, it's likely the archive is corrupted or not a squashfs archive.
+    pub fn validate(self: Superblock) !void {
+        if (self.magic != SQUASHFS_MAGIC)
+            return SuperblockError.InvalidMagic;
+        if (self.flags.check)
+            return SuperblockError.InvalidCheck;
+        if (self.ver_maj != 4 or self.ver_min != 0)
+            return SuperblockError.InvalidVersion;
+        if (std.math.log2(self.block_size) != self.block_log)
+            return SuperblockError.InvalidBlockLog;
+    }
+};

src/bin/unsquashfs.zig

@@ -1,146 +1,140 @@
 const std = @import("std");
-const config = @import("config");
-const squashfs = @import("squashfs");
+const Io = std.Io;
+const Writer = Io.Writer;
+const builtin = @import("builtin");
 
-const help_msg =
-    \\Basic Usage: zig-unsquashfs [Options] SQUASHFS_FILE <EXTRACT_LOCATION>
+const config = @import("config");
+const squashfs = @import("zig_squashfs");
+
+//TODO: Add more options
+const help_mgs =
     \\
-    \\General options:
-    \\  -e <path>           Path to a file or directory inside the archive to extract instead of the whole archive.
-    \\                          Can be given multiple times.
-    \\  -o <bytes>          Skip <bytes> before reading from the archive.
-    \\  -v                  Verbose output.
+    \\Usage: unsquashfs [options] <archive>
     \\
-    \\Extraction options:
-    \\  --unbreak-symlinks  Attempt extract symlink targets along with symlinks. Will not place files outside of the extraction location.
-    \\  -us                 Same as --unbreak-symlinks
-    \\  --deref-symlinks    Replace symlink files with their target.
-    \\  -ds                 Same as --deref-symlinks
-    \\  -p <#>              Use at most # of processors. Defaults to logical core count.
+    \\Options:
+    \\  -d <location>   Extract to the given location instead of "squashfs-root"
     \\
-    \\Listing Options:
-    \\  -l                  List files instead of extracting. When used, you do not need to specify an extraction location.
-    \\  -ll                 Similiar to -l, but with file attributes.
-    \\  -lln                Similiar to -ll, but with numeric uids and gids.
+    \\  -o <offset>     Start reading the archive at the given offset.
+    \\  -dx             Don't set xattr values
+    \\  -dp             Don't set permissions (includes setting uid & gid owner)
     \\
-    \\Other:
-    \\  --help              Prints this help message.
-    \\  -h                  Same as --help
-    \\  --version           Print version number.
+    \\  -p <threads>    Specify how many threads to use. If not present or zero, the system's logical cores count is used.
+    \\  -v              Verbose
+    \\
+    \\  --force         Force extraction. If the destination already exists, it will be deleted.
+    \\
+    \\  --help          Display this messages
+    \\  --version       Display the version
     \\
 ;
 
-const stdout = std.io.getStdOut();
+const errors = error{InvalidArguments};
 
-var extr_files: std.ArrayList([]const u8) = undefined;
+var archive: []const u8 = "";
+var extLoc: []const u8 = "squashfs-root";
 var offset: u64 = 0;
+var threads: u32 = 0;
 var verbose: bool = false;
-var unbreak: bool = false;
-var deref: bool = false;
-var processors: u16 = 0;
-var list: ListTypes = .None;
+var ignore_xattrs: bool = false;
+var ignore_permissions: bool = false;
+var force: bool = false;
 
-var filename: []const u8 = "";
-var extr_location: []const u8 = "";
+pub fn main(init: std.process.Init) !void {
+    const alloc = init.gpa;
+    const io = init.io;
 
-const ListTypes = enum {
-    None,
-    List,
-    ListAttr,
-    ListNumeric,
-};
+    var stdout = std.Io.File.stdout();
+    defer stdout.close(io);
+    var out = stdout.writer(io, &[0]u8{});
+    defer out.interface.flush() catch {};
 
-pub fn main() !void {
-    const alloc = std.heap.smp_allocator;
-    extr_files = .init(alloc);
-    defer extr_files.deinit();
-    var args = std.process.argsWithAllocator(alloc) catch {
-        _ = try stdout.writeAll("Unable to allocate memory");
+    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 = try Io.Dir.cwd().openFile(io, archive, .{}); //TODO: Handle error gracefully.
+    defer fil.close(io);
+
+    var arc: squashfs.Archive = try .init(io, fil, offset); //TODO: Handle error gracefully.
+    const options: squashfs.ExtractionOptions = .{
+        .threads = if (threads == 0) try std.Thread.getCpuCount() else threads,
+        .verbose = verbose,
+        .verbose_writer = if (verbose) &out.interface else null,
+        .ignore_xattr = ignore_xattrs,
+        .ignore_permissions = ignore_permissions,
     };
-    defer args.deinit();
-    _ = args.next();
-    while (args.next()) |arg| {
-        if (std.mem.eql(u8, arg, "--help") or std.mem.eql(u8, arg, "-h")) {
-            _ = try stdout.writeAll(help_msg);
-            return;
-        } else if (std.mem.eql(u8, arg, "--version")) {
-            try config.version.format("", .{}, stdout.writer());
-            _ = try stdout.write("\n");
-            return;
+
+    if (force)
+        try Io.Dir.cwd().deleteTree(io, extLoc);
+    try arc.extract(alloc, io, extLoc, options); //TODO: Handle error gracefully.
+}
+
+fn handleArgs(args: std.process.Args, out: *Writer) !void {
+    var arg_iter = args.iterate();
+    defer arg_iter.deinit();
+    _ = arg_iter.next(); // args[0] is the application launch command.
+    while (arg_iter.next()) |arg| {
+        if (std.mem.eql(u8, arg, "-o")) {
+            const nxt = arg_iter.next();
+            if (nxt == null or nxt.?.len == 0) {
+                try out.print("-o must be followed by a number\n", .{});
+                return errors.InvalidArguments;
+            }
+            offset = std.fmt.parseInt(u64, nxt.?, 10) catch {
+                try out.print("-o must be followed by a number\n", .{});
+                return errors.InvalidArguments;
+            };
+            continue;
+        } else if (std.mem.eql(u8, arg, "-d")) {
+            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;
+            }
+            extLoc = nxt.?;
+            continue;
+        } else if (std.mem.eql(u8, arg, "-p")) {
+            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;
+            }
+            threads = std.fmt.parseInt(u32, nxt.?, 10) catch {
+                try out.print("-p must be followed by a number\n", .{});
+                return errors.InvalidArguments;
+            };
+            continue;
         } else if (std.mem.eql(u8, arg, "-v")) {
             verbose = true;
-        } else if (std.mem.eql(u8, arg, "--unbreak-symlinks") or std.mem.eql(u8, arg, "-us")) {
-            unbreak = true;
-        } else if (std.mem.eql(u8, arg, "--deref-symlinks") or std.mem.eql(u8, arg, "-ds")) {
-            deref = true;
-        } else if (std.mem.eql(u8, arg, "-l")) {
-            list = .List;
-        } else if (std.mem.eql(u8, arg, "-ll")) {
-            list = .ListAttr;
-        } else if (std.mem.eql(u8, arg, "-lln")) {
-            list = .ListNumeric;
-        } else if (std.mem.eql(u8, arg, "-e")) {
-            const next = args.next();
-            if (next == null) {
-                _ = try stdout.writeAll("path required after -e\n");
-                return;
-            }
-            try extr_files.append(next.?);
-        } else if (std.mem.eql(u8, arg, "-o")) {
-            const next = args.next();
-            if (next == null) {
-                _ = try stdout.writeAll("offset required after -o\n");
-                return;
-            }
-            offset = try std.fmt.parseInt(u64, next.?, 10);
-        } else if (std.mem.eql(u8, arg, "-p")) {
-            const next = args.next();
-            if (next == null) {
-                _ = try stdout.writeAll("number required after -p\n");
-                return;
-            }
-            processors = try std.fmt.parseInt(u16, next.?, 10);
-        } else if (filename.len == 0) {
-            filename = arg;
-        } else if (extr_location.len == 0) {
-            extr_location = arg;
-        } else {
-            _ = try stdout.writeAll("invalid or too many arguments\n");
+            continue;
+        } else if (std.mem.eql(u8, arg, "-dx")) {
+            ignore_xattrs = true;
+            continue;
+        } else if (std.mem.eql(u8, arg, "-dp")) {
+            ignore_permissions = true;
+            continue;
+        } else if (std.mem.eql(u8, arg, "--force")) {
+            force = true;
+            continue;
+        } else if (std.mem.eql(u8, arg, "--version")) {
+            try out.print("zig-unsquashfs v", .{});
+            try config.version.format(out);
+            try out.print("\nBuilt using Zig {s} in {} mode\n", .{ builtin.zig_version_string, builtin.mode });
+            std.process.exit(0);
+            return;
+        } else if (std.mem.eql(u8, arg, "--help")) {
+            try out.print(help_mgs, .{});
+            std.process.exit(0);
             return;
         }
+        if (archive.len > 0) {
+            try out.print("you can only provide one file at a time\n", .{});
+            try out.print(help_mgs, .{});
+            return errors.InvalidArguments;
+        }
+        archive = arg;
     }
-    if (filename.len == 0) {
-        _ = try stdout.writeAll("no archive given\n");
-        return;
-    }
-    if (list == .None and extr_location.len == 0) {
-        _ = try stdout.writeAll("no extract location given\n");
-        return;
-    }
-    const fil = try std.fs.cwd().openFile(filename, .{});
-    defer fil.close();
-    var th_alloc: std.heap.ThreadSafeAllocator = .{ .child_allocator = std.heap.smp_allocator };
-    var rdr = squashfs.SfsFile.init(
-        th_alloc.allocator(),
-        fil,
-        offset,
-    ) catch |err| {
-        try std.fmt.format(stdout.writer(), "Error opening {s} as squashfs: {any}\n", .{ filename, err });
-        return;
-    };
-    defer rdr.deinit();
-    //TODO: list and extr_files;
-    var op: squashfs.ExtractionOptions = squashfs.ExtractionOptions.init() catch |err| {
-        try std.fmt.format(stdout.writer(), "Error setting extraction options: {any}\n", .{err});
-        return;
-    };
-    op.verbose = verbose;
-    op.dereference_symlinks = deref;
-    op.unbreak_symlinks = unbreak;
-    if (processors != 0) op.thread_count = processors;
-    rdr.extract(op, extr_location) catch |err| {
-        try std.fmt.format(stdout.writer(), "Error extracting archive: {any}\n", .{err});
-        return;
-    };
 }

src/decomp.zig

@@ -0,0 +1,32 @@
+const std = @import("std");
+
+const Decompressor = @import("util/decompressor.zig");
+
+pub const Decomp = union(enum) {
+    gzip: @import("decomp/zlib.zig"),
+    lzma: @import("decomp/lzma.zig"),
+    lzo: void,
+    xz: @import("decomp/xz.zig"),
+    lz4: void,
+    zstd: @import("decomp/zstd.zig"),
+
+    pub fn deinit(self: *Decomp) void {
+        switch (self.*) {
+            .gzip => self.gzip.deinit(),
+            .lzma => self.lzma.deinit(),
+            .xz => self.xz.deinit(),
+            .zstd => self.zstd.deinit(),
+            else => unreachable,
+        }
+    }
+
+    pub fn decompressor(self: *Decomp) *Decompressor {
+        return switch (self.*) {
+            .gzip => &self.gzip.interface,
+            .lzma => &self.lzma.interface,
+            .xz => &self.xz.interface,
+            .zstd => &self.zstd.interface,
+            else => unreachable,
+        };
+    }
+};

src/decomp/lzma.zig

@@ -0,0 +1,86 @@
+const std = @import("std");
+const Reader = std.Io.Reader;
+const lzma = std.compress.lzma;
+const Node = std.SinglyLinkedList.Node;
+
+const Decompressor = @import("../util/decompressor.zig");
+const Error = Decompressor.Error;
+
+const Self = @This();
+
+const Buffer = struct {
+    node: Node,
+    buf: []u8,
+};
+
+interface: Decompressor = .{ .decomp_fn = decomp },
+
+alloc: std.mem.Allocator,
+
+block_size: u32,
+buffers: std.ArrayList(Buffer),
+buffer_queue: std.SinglyLinkedList = .{},
+
+pub fn init(alloc: std.mem.Allocator, block_size: u32) !Self {
+    return .{
+        .alloc = alloc,
+
+        .block_size = block_size,
+        .buffers = try .initCapacity(alloc, 5),
+    };
+}
+pub fn deinit(self: *Self) void {
+    for (self.buffers.items) |buf|
+        self.alloc.free(buf.buf);
+    self.buffers.deinit(self.alloc);
+}
+
+fn decomp(d: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    if (d == null) {
+        var buf = try alloc.alloc(u8, in.len * 2);
+        defer alloc.free(buf);
+        return lzmaDecomp(alloc, &buf, in, out) catch |err| return switch (err) {
+            error.OutOfMemory => Error.OutOfMemory,
+            else => Error.ReadFailed,
+        };
+    }
+    var self: *Self = @fieldParentPtr("interface", @constCast(d.?));
+    const buf_node = self.buffer_queue.popFirst();
+    var buf: *Buffer = undefined;
+    if (buf_node == null) {
+        const new_buf = try self.buffers.addOne(self.alloc);
+        new_buf.* = .{ .node = .{}, .buf = try self.alloc.alloc(u8, self.block_size) };
+        buf = new_buf;
+    } else {
+        buf = @fieldParentPtr("node", buf_node.?);
+    }
+    defer self.buffer_queue.prepend(&buf.node);
+    return lzmaDecomp(self.alloc, &buf.buf, in, out) catch |err| {
+        // self.err = err;
+        return switch (err) {
+            error.OutOfMemory => Error.OutOfMemory,
+            else => Error.ReadFailed,
+        };
+    };
+}
+
+inline fn lzmaDecomp(alloc: std.mem.Allocator, buffer: *[]u8, in: []u8, out: []u8) !usize {
+    var rdr: Reader = .fixed(in);
+    var d = try lzma.Decompress.initOptions(&rdr, alloc, buffer.*, .{ .allow_incomplete = true }, 3 * 1024 * 1024);
+    defer {
+        buffer.* = d.takeBuffer();
+        d.deinit();
+    }
+
+    return d.reader.readSliceShort(out);
+}
+
+// Stateless
+
+pub const stateless_decompressor: Decompressor = .{ .decomp_fn = statelessDecomp };
+
+fn statelessDecomp(_: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    var buf = try alloc.alloc(u8, in.len);
+    defer alloc.free(buf);
+    return lzmaDecomp(alloc, &buf, in, out) catch return Error.ReadFailed;
+}

src/decomp/xz.zig

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

src/decomp/zlib.zig

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

src/decomp/zstd.zig

@@ -0,0 +1,74 @@
+const std = @import("std");
+const Io = std.Io;
+const Reader = std.Io.Reader;
+const zstd = std.compress.zstd;
+const Node = std.SinglyLinkedList.Node;
+
+const Decompressor = @import("../util/decompressor.zig");
+const Error = Decompressor.Error;
+
+const Queue = std.Io.Queue([]u8);
+
+const Self = @This();
+
+interface: Decompressor = .{ .decomp_fn = decomp },
+
+alloc: std.mem.Allocator,
+io: Io,
+
+block_size: u32,
+buf: [][]u8,
+buf_queue: Queue,
+
+pub fn init(alloc: std.mem.Allocator, io: Io, block_size: u32) !Self {
+    const buf = try alloc.alloc([]u8, 20); // TODO: Choose a better number instead of a random one.
+    var queue: Queue = .init(buf);
+    for (0..20) |_|
+        try queue.putOne(io, try alloc.alloc(u8, block_size + zstd.block_size_max));
+
+    return .{
+        .alloc = alloc,
+        .io = io,
+
+        .block_size = block_size,
+        .buf = buf,
+        .buf_queue = queue,
+    };
+}
+pub fn deinit(self: *Self) void {
+    self.buf_queue.close(self.io);
+    for (self.buf) |buf|
+        self.alloc.free(buf);
+    self.alloc.free(self.buf);
+}
+
+fn decomp(d: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    if (d == null) {
+        const buf = try alloc.alloc(u8, in.len * 2);
+        defer alloc.free(buf);
+        return zstdDecomp(buf, in, out);
+    }
+    var self: *Self = @fieldParentPtr("interface", @constCast(d.?));
+
+    const buf = self.buf_queue.getOne(self.io) catch return Error.ReadFailed;
+    defer self.buf_queue.putOne(self.io, buf) catch {};
+
+    return zstdDecomp(buf, in, out);
+}
+
+inline fn zstdDecomp(buffer: []u8, in: []u8, out: []u8) !usize {
+    var rdr: Reader = .fixed(in);
+    var d = zstd.Decompress.init(&rdr, buffer, .{ .window_len = @truncate(out.len) });
+
+    return d.reader.readSliceShort(out);
+}
+
+// Stateless
+
+pub const stateless_decompressor: Decompressor = .{ .decomp_fn = statelessDecomp };
+
+fn statelessDecomp(_: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
+    const buf = try alloc.alloc(u8, out.len + zstd.block_size_max);
+    defer alloc.free(buf);
+    return zstdDecomp(buf, in, out);
+}

src/directory.zig

@@ -1,70 +1,69 @@
 const std = @import("std");
+const Reader = std.Io.Reader;
 
-const InodeType = @import("inode.zig").Type;
-const Compression = @import("superblock.zig").Compression;
+const Inode = @import("inode.zig");
 
-const Header = extern struct { //use extern instead of packed, due to bit alignment
-    count: u32,
-    block: u32,
-    num: u32,
-};
+pub const Error = error{OutOfMemory} || Reader.Error;
 
-const RawEntry = struct {
-    offset: u16,
-    num_offset: i16,
-    type: InodeType,
-    size: u16,
-    name: []const u8,
+const DirEntry = @This();
 
-    pub fn init(alloc: std.mem.Allocator, rdr: anytype) !RawEntry {
-        var fixed: [8]u8 = undefined;
-        _ = try rdr.read(&fixed);
-        const size = std.mem.readInt(u16, fixed[6..8], .little);
-        const name = try alloc.alloc(u8, size + 1);
-        _ = try rdr.read(name);
-        return .{
-            .offset = std.mem.readInt(u16, fixed[0..2], .little),
-            .num_offset = std.mem.readInt(i16, fixed[2..4], .little),
-            .type = @enumFromInt(std.mem.readInt(u16, fixed[4..6], .little)),
-            .size = size,
-            .name = name,
-        };
-    }
-};
+block_start: u32,
+block_offset: u16,
+type: Inode.Type,
+name: []const u8,
 
-pub const Entry = struct {
-    block: u32,
-    offset: u16,
-    num: u32,
-    type: InodeType,
-    name: []const u8,
+pub fn deinit(self: DirEntry, alloc: std.mem.Allocator) void {
+    alloc.free(self.name);
+}
 
-    pub fn deinit(self: Entry, alloc: std.mem.Allocator) void {
-        alloc.free(self.name);
-    }
-};
-
-pub fn readDirectory(alloc: std.mem.Allocator, rdr: anytype, size: u32) ![]Entry {
-    var entries: std.ArrayList(Entry) = .init(alloc);
-    errdefer entries.deinit();
-    var cur_red: u32 = 3; // dir size includes "." & "..", so its actual size is off by 3.
+pub fn readDirectory(alloc: std.mem.Allocator, rdr: *Reader, size: u32) Error![]DirEntry {
     var hdr: Header = undefined;
-    while (cur_red < size) {
-        _ = try rdr.read(std.mem.asBytes(&hdr));
-        cur_red += 12;
-        try entries.ensureUnusedCapacity(hdr.count + 1);
+    var raw: RawEntry = undefined;
+    var out: std.ArrayList(DirEntry) = try .initCapacity(alloc, 30);
+    errdefer {
+        for (out.items) |ent|
+            alloc.free(ent.name);
+        out.deinit(alloc);
+    }
+
+    var tot_red: u32 = 3;
+    while (tot_red < size) {
+        try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
+        try out.ensureUnusedCapacity(alloc, hdr.count + 1);
+
+        tot_red += @sizeOf(Header);
+
         for (0..hdr.count + 1) |_| {
-            const raw_ent: RawEntry = try .init(alloc, rdr);
-            cur_red += 9 + raw_ent.size;
-            errdefer alloc.free(raw_ent.name);
-            entries.appendAssumeCapacity(.{
-                .block = hdr.block,
-                .offset = raw_ent.offset,
-                .num = @truncate(@abs(@as(i64, hdr.num) + raw_ent.num_offset)),
-                .type = raw_ent.type,
-                .name = raw_ent.name,
-            });
+            try rdr.readSliceEndian(RawEntry, @ptrCast(&raw), .little);
+
+            const new_name = try alloc.alloc(u8, raw.name_size + 1);
+            try rdr.readSliceEndian(u8, new_name, .little);
+
+            const new = out.addOneAssumeCapacity();
+            new.* = .{
+                .block_start = hdr.block_start,
+                .block_offset = raw.block_offset,
+                .type = raw.type,
+                .name = new_name,
+            };
+
+            tot_red += @sizeOf(RawEntry) + raw.name_size + 1;
         }
     }
-    return entries.toOwnedSlice();
+    return out.toOwnedSlice(alloc);
 }
+
+// Types
+
+const Header = extern struct {
+    count: u32,
+    block_start: u32,
+    num: u32,
+};
+
+const RawEntry = extern struct {
+    block_offset: u16,
+    num_offset: i16,
+    type: Inode.Type,
+    name_size: u16,
+};

src/extract_options.zig

@@ -1,23 +0,0 @@
-const std = @import("std");
-
-const Self = @This();
-
-/// Replace symlinks with their targets
-dereference_symlinks: bool = false,
-/// Always extract a symlink's target if it's part of the archive.
-/// May result in the symlink's target being changed.
-unbreak_symlinks: bool = false,
-/// Do not set file's permissions & owner when extracted.
-ignore_permissions: bool = false,
-/// Verbose logging
-verbose: bool = false,
-/// Verbose logging writer. If not set, stdout is used.
-verbose_logger: std.io.AnyWriter = std.io.getStdOut().writer().any(),
-/// Number of threads used during extraction. Defualts to std.Thread.getCpuCount().
-thread_count: usize,
-
-pub fn init() !Self {
-    return .{
-        .thread_count = try std.Thread.getCpuCount(),
-    };
-}

src/file.zig

@@ -1,355 +1,95 @@
+//! An easier to use wrapper around an inode.
+
 const std = @import("std");
-const builtin = @import("builtin");
+const Io = std.Io;
 
-const dir = @import("directory.zig");
-
-const DirEntry = dir.Entry;
+const Archive = @import("archive.zig");
+const DirEntry = @import("directory.zig");
+const ExtractionOptions = @import("options.zig");
 const Inode = @import("inode.zig");
-const SfsReader = @import("reader.zig").SfsReader;
-const ToReader = @import("reader/to_read.zig").ToRead;
-const ExtractionOptions = @import("extract_options.zig");
-const DataReader = @import("reader/data.zig").DataReader;
-const Compression = @import("superblock.zig").Compression;
-const MetadataReader = @import("reader/metadata.zig").MetadataReader;
+const DataExtractor = @import("util/data_extractor.zig");
+const Decompressor = @import("util/decompressor.zig");
+const MetadataReader = @import("util/metadata.zig");
+const SharedCache = @import("util/shared_cache.zig");
 
-pub fn File(comptime T: type) type {
-    return struct {
-        pub const FileError = error{
-            NotRegular,
-            NotDirectory,
-            NotFound,
-        };
+const File = @This();
 
-        const Self = @This();
+alloc: std.mem.Allocator,
 
-        rdr: *SfsReader(T),
-        // parent: *File(T),
+archive: Archive,
 
-        inode: Inode,
-        name: []const u8,
+inode: Inode,
+name: []const u8,
 
-        /// Directory entries. Only populated on directories.
-        entries: ?[]DirEntry = null,
-        /// File reader. Only populated on regular files.
-        data_reader: ?DataReader(T) = null,
+/// Creates a new File from an inode. Takes ownership of the Inode and creates a copy of the given name.
+/// Requires the given allocator was used to create the Inode.
+pub fn init(alloc: std.mem.Allocator, archive: Archive, in: Inode, name: []const u8) !File {
+    const new_name = try alloc.alloc(u8, name.len);
+    @memcpy(new_name, name);
+    return .{
+        .alloc = alloc,
 
-        pub fn init(rdr: *SfsReader(T), inode: Inode, name: []const u8) !Self {
-            const name_cpy: []u8 = try rdr.alloc.alloc(u8, name.len);
-            @memcpy(name_cpy, name);
-            var out = Self{
-                .rdr = rdr,
-                .inode = inode,
-                .name = name_cpy,
-            };
-            switch (inode.data) {
-                .dir => |d| {
-                    var meta = MetadataReader(T).init(
-                        rdr.alloc,
-                        rdr.super.comp,
-                        rdr.rdr,
-                        d.block + rdr.super.dir_start,
-                    );
-                    try meta.skip(d.offset);
-                    out.entries = try dir.readDirectory(rdr.alloc, &meta, d.size);
-                },
-                .ext_dir => |d| {
-                    var meta = MetadataReader(T).init(
-                        rdr.alloc,
-                        rdr.super.comp,
-                        rdr.rdr,
-                        d.block + rdr.super.dir_start,
-                    );
-                    try meta.skip(d.offset);
-                    out.entries = try dir.readDirectory(rdr.alloc, &meta, d.size);
-                },
-                .file => |f| {
-                    out.data_reader = try .init(rdr, inode);
-                    _ = f;
-                    //TODO: fragments
-                    // if (f.hasFragment()) {
-                    //     try out.data_reader.?.addFragment(
-                    //         try rdr.frag_table.get(f.frag_idx),
-                    //         f.frag_offset,
-                    //     );
-                    // }
-                },
-                .ext_file => |f| {
-                    out.data_reader = try .init(rdr, inode);
-                    _ = f;
-                    //TODO: Fragments
-                    // if (f.hasFragment()) {
-                    //     try out.data_reader.?.addFragment(
-                    //         try rdr.frag_table.get(f.frag_idx),
-                    //         f.frag_offset,
-                    //     );
-                    // }
-                },
-                else => {},
-            }
-            return out;
-        }
-        pub fn initFromRef(rdr: *SfsReader(T), ref: Inode.Ref, name: []const u8) !Self {
-            var meta: MetadataReader(T) = .init(rdr.alloc, rdr.super.comp, rdr.rdr, ref.block + rdr.super.inode_start);
-            try meta.skip(ref.offset);
-            const inode: Inode = try .init(&meta, rdr.alloc, rdr.super.block_size);
-            return .init(rdr, inode, name);
-        }
-        pub fn initFromEntry(rdr: *SfsReader(T), ent: DirEntry) !Self {
-            var meta: MetadataReader(T) = .init(rdr.alloc, rdr.super.comp, rdr.rdr, ent.block + rdr.super.inode_start);
-            try meta.skip(ent.offset);
-            const inode: Inode = try .init(&meta, rdr.alloc, rdr.super.block_size);
-            return .init(rdr, inode, ent.name);
-        }
-        pub fn deinit(self: *Self) void {
-            self.rdr.alloc.free(self.name);
-            self.inode.deinit(self.rdr.alloc);
-            if (self.entries != null) {
-                for (self.entries.?) |e| {
-                    e.deinit(self.rdr.alloc);
-                }
-                self.rdr.alloc.free(self.entries.?);
-            }
-            if (self.data_reader != null) {
-                self.data_reader.?.deinit();
-            }
-        }
+        .archive = archive,
 
-        pub fn uid(self: Self) !u32 {
-            return self.rdr.id_table.get(self.inode.hdr.uid_idx);
-        }
-        pub fn gid(self: Self) !u32 {
-            return self.rdr.id_table.get(self.inode.hdr.uid_idx);
-        }
-
-        const Reader = std.io.GenericReader(*DataReader(T), anyerror, DataReader(T).read);
-
-        pub fn read(self: *Self, buf: []u8) !usize {
-            if (self.data_reader == null) return FileError.NotRegular;
-            return self.data_reader.?.read(buf);
-        }
-        pub fn reader(self: *Self) !Reader {
-            if (self.data_reader == null) return FileError.NotRegular;
-            return self.data_reader.?.reader();
-        }
-
-        pub fn open(self: Self, path: []const u8) !Self {
-            if (self.entries == null) return FileError.NotDirectory;
-            if (path.len == 0) return self;
-            const idx = std.mem.indexOf(u8, path, "/") orelse path.len;
-            if (idx == 0) return self.open(path[1..]);
-            const name = path[0..idx];
-            for (self.entries.?) |e| {
-                if (std.mem.eql(u8, e.name, name)) {
-                    var fil: Self = try .initFromEntry(self.rdr, e);
-                    if (idx >= path.len - 1) return fil;
-                    defer fil.deinit();
-                    return fil.open(path[idx + 1 ..]);
-                }
-            }
-            return FileError.NotFound;
-        }
-        pub fn iterate(self: Self) Iterator {
-            return .{
-                .rdr = self.rdr,
-                .entries = self.entries.?,
-            };
-        }
-
-        const Iterator = struct {
-            rdr: *SfsReader(T),
-            entries: []DirEntry,
-
-            idx: u32 = 0,
-
-            pub fn next(self: *Iterator) !?File(T) {
-                if (self.idx >= self.entries.len) return null;
-                const out = try Self.initFromEntry(self.rdr, self.entries[self.idx]);
-                self.idx += 1;
-                return out;
-            }
-            pub fn reset(self: *Iterator) void {
-                self.idx = 0;
-            }
-        };
-
-        const WaitGroup = std.Thread.WaitGroup;
-        const Pool = std.Thread.Pool;
-        const Mutex = std.Thread.Mutex;
-
-        pub const ExtractError = error{FileExists};
-
-        pub fn extract(self: *Self, op: ExtractionOptions, path: []const u8) !void {
-            var wg: WaitGroup = .{};
-            var pol: Pool = undefined;
-            try pol.init(.{
-                .n_jobs = op.thread_count,
-                .allocator = self.rdr.alloc,
-            });
-            defer pol.deinit();
-            var errs: std.ArrayList(anyerror) = .init(self.rdr.alloc);
-            defer errs.deinit();
-            try self.extractInode(op, &wg, &errs, &pol, self.inode, path);
-            wg.wait();
-            if (errs.items.len > 0) return errs.items[0];
-        }
-        fn extractInode(
-            self: *Self,
-            op: ExtractionOptions,
-            wg: *WaitGroup,
-            errs: *std.ArrayList(anyerror),
-            pol: *Pool,
-            inode: Inode,
-            path: []const u8,
-        ) !void {
-            wg.start();
-            defer wg.finish(); //TODO: When everthing is threaded, this will need to be handled by the threads, not here.
-            switch (inode.hdr.type) {
-                .file, .ext_file => {
-                    var fil = try std.fs.cwd().createFile(path, .{});
-                    defer fil.close();
-                    var data: DataReader(T) = try .init(self.rdr, inode);
-                    defer data.deinit();
-                    try data.writeTo(fil); // TODO: Thread
-                    const fil_uid = self.rdr.id_table.get(inode.hdr.uid_idx) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error getting uid {} from table: {}\n", .{ inode.hdr.uid_idx, err }) catch {};
-                        }
-                        return;
-                    };
-                    const fil_gid = self.rdr.id_table.get(inode.hdr.gid_idx) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error getting gid {} from table: {}\n", .{ inode.hdr.gid_idx, err }) catch {};
-                        }
-                        return;
-                    };
-                    fil.chmod(inode.hdr.perm) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error chmod {s}: {}\n", .{ path, err }) catch {};
-                        }
-                        return;
-                    };
-                    fil.chown(fil_uid, fil_gid) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error chmod {s}: {}\n", .{ path, err }) catch {};
-                        }
-                        return;
-                    };
-                    //TODO: update mtime.
-                },
-                .dir, .ext_dir => {
-                    std.fs.cwd().makeDir(path) catch |err| {
-                        if (err != std.fs.Dir.MakeError.PathAlreadyExists) {
-                            return err;
-                        }
-                    };
-                    var dir_block: u32 = 0;
-                    var dir_offset: u16 = 0;
-                    var dir_size: u32 = 0;
-                    switch (inode.data) {
-                        .dir => |d| {
-                            dir_block = d.block;
-                            dir_offset = d.offset;
-                            dir_size = d.size;
-                        },
-                        .ext_dir => |d| {
-                            dir_block = d.block;
-                            dir_offset = d.offset;
-                            dir_size = d.size;
-                        },
-                        else => unreachable,
-                    }
-                    var meta: MetadataReader(T) = .init(self.rdr.alloc, self.rdr.super.comp, self.rdr.rdr, dir_block + self.rdr.super.dir_start);
-                    try meta.skip(dir_offset);
-                    const entries = try dir.readDirectory(self.rdr.alloc, &meta, dir_size);
-                    defer self.rdr.alloc.free(entries);
-                    for (entries) |ent| {
-                        defer ent.deinit(self.rdr.alloc);
-                        var new_path: []u8 = undefined;
-                        if (path[path.len - 1] == '/') {
-                            new_path = self.rdr.alloc.alloc(u8, path.len + ent.name.len) catch |err| {
-                                if (op.verbose) {
-                                    std.fmt.format(op.verbose_logger, "error allocating memory: {}\n", .{err}) catch {};
-                                }
-                                errs.append(err) catch {};
-                                continue;
-                            };
-                            @memcpy(new_path[0..path.len], path);
-                            @memcpy(new_path[path.len..], ent.name);
-                        } else {
-                            new_path = self.rdr.alloc.alloc(u8, path.len + ent.name.len + 1) catch |err| {
-                                if (op.verbose) {
-                                    std.fmt.format(op.verbose_logger, "error allocating memory: {}\n", .{err}) catch {};
-                                }
-                                errs.append(err) catch {};
-                                continue;
-                            };
-                            @memcpy(new_path[0..path.len], path);
-                            new_path[path.len] = '/';
-                            @memcpy(new_path[path.len + 1 ..], ent.name);
-                        }
-                        defer self.rdr.alloc.free(new_path);
-
-                        meta = .init(self.rdr.alloc, self.rdr.super.comp, self.rdr.rdr, ent.block + self.rdr.super.inode_start);
-                        meta.skip(ent.offset) catch |err| {
-                            if (op.verbose) {
-                                std.fmt.format(op.verbose_logger, "error reading inode: {}\n", .{err}) catch {};
-                            }
-                            errs.append(err) catch {};
-                            continue;
-                        };
-                        const new_inode = Inode.init(&meta, self.rdr.alloc, self.rdr.super.block_size) catch |err| {
-                            if (op.verbose) {
-                                std.fmt.format(op.verbose_logger, "error reading inode: {}\n", .{err}) catch {};
-                            }
-                            errs.append(err) catch {};
-                            continue;
-                        };
-                        defer new_inode.deinit(self.rdr.alloc);
-                        self.extractInode(op, wg, errs, pol, new_inode, new_path) catch |err| {
-                            if (op.verbose) {
-                                std.fmt.format(op.verbose_logger, "error extracting {s}: {}\n", .{ new_path, err }) catch {};
-                            }
-                            errs.append(err) catch {};
-                            continue;
-                        };
-                    }
-
-                    var fil = std.fs.cwd().openDir(path, .{ .iterate = true }) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error openning {s} to set permissions: {}\n", .{ path, err }) catch {};
-                        }
-                        return;
-                    };
-                    const fil_uid = self.rdr.id_table.get(inode.hdr.uid_idx) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error getting uid {} from table: {}\n", .{ inode.hdr.uid_idx, err }) catch {};
-                        }
-                        return;
-                    };
-                    const fil_gid = self.rdr.id_table.get(inode.hdr.gid_idx) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error getting gid {} from table: {}\n", .{ inode.hdr.gid_idx, err }) catch {};
-                        }
-                        return;
-                    };
-                    fil.chmod(inode.hdr.perm) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error chmod {s}: {}\n", .{ path, err }) catch {};
-                        }
-                        return;
-                    };
-                    fil.chown(fil_uid, fil_gid) catch |err| {
-                        if (op.verbose) {
-                            std.fmt.format(op.verbose_logger, "error chmod {s}: {}\n", .{ path, err }) catch {};
-                        }
-                        return;
-                    };
-                },
-                // .symlink, .ext_symlink => {},
-                else => {
-                    std.debug.print("TODO: {}\n", .{inode.hdr.type});
-                },
-            }
-        }
+        .inode = in,
+        .name = new_name,
     };
 }
+pub fn fromDirEntry(alloc: std.mem.Allocator, io: Io, archive: Archive, ent: DirEntry) !File {
+    var rdr = try archive.file.readerAt(io, archive.super.inode_start + ent.block_start, &[0]u8{});
+    var meta: MetadataReader = .init(alloc, &rdr.interface, &archive.stateless_decomp);
+    try meta.interface.discardAll(ent.block_offset);
+
+    var in: Inode = try .read(alloc, &meta.interface, archive.super.block_size);
+    errdefer in.deinit(alloc);
+    return .init(alloc, archive, in, ent.name);
+}
+pub fn deinit(self: File) void {
+    self.alloc.free(self.name);
+    self.inode.deinit(self.alloc);
+}
+
+pub fn open(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8) !File {
+    const entries = try self.inode.readDirectory(
+        alloc,
+        io,
+        self.archive.file,
+        &self.archive.stateless_decomp,
+        self.archive.super.dir_start,
+    );
+    defer {
+        for (entries) |ent|
+            alloc.free(ent.name);
+        alloc.free(entries);
+    }
+    const path = std.mem.trim(u8, filepath, "/");
+    const first_element: []const u8 = std.mem.sliceTo(path, '/');
+
+    var search_slice = entries;
+    var idx: usize = undefined;
+    while (search_slice.len > 0) {
+        idx = search_slice.len / 2;
+        const middle = search_slice[idx];
+        switch (std.mem.order(u8, first_element, middle.name)) {
+            .eq => break,
+            .lt => search_slice = search_slice[0..idx],
+            .gt => search_slice = search_slice[idx + 1 ..],
+        }
+    } else return Error.FileNotFound;
+
+    const first_elem_file = try fromDirEntry(alloc, io, self.archive, search_slice[idx]);
+    if (first_element.len == path.len)
+        return first_elem_file;
+    defer first_elem_file.deinit();
+    return first_elem_file.open(alloc, io, path[first_element.len + 1 ..]);
+}
+
+pub fn extract(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8, options: ExtractionOptions) !void {
+    return self.inode.extract(alloc, io, self.archive.file, self.archive.super, filepath, options);
+}
+
+// Types
+
+pub const Error = error{
+    FileNotFound,
+} || Inode.Error;

src/frag.zig

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

src/fragment.zig

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

src/inode.zig

@@ -1,13 +1,165 @@
+//! A file-system object. Represents a File or directory.
+
 const std = @import("std");
+const Reader = std.Io.Reader;
+const Io = std.Io;
 
-const dir = @import("inode/dir.zig");
-const file = @import("inode/file.zig");
-const misc = @import("inode/misc.zig");
+const Archive = @import("archive.zig");
+const Decomp = @import("decomp.zig").Decomp;
+const DirEntry = @import("directory.zig");
+const ExtractionOptions = @import("options.zig");
+const FragEntry = @import("frag.zig").FragEntry;
+const dir = @import("inode_data/dir.zig");
+const file = @import("inode_data/file.zig");
+const misc = @import("inode_data/misc.zig");
+const LookupTable = @import("lookup_table.zig");
+const CachedTable = LookupTable.CachedTable;
+const DataExtractor = @import("util/data_extractor.zig");
+const DataReader = @import("util/data_reader.zig");
+const Decompressor = @import("util/decompressor.zig");
+const MetadataReader = @import("util/metadata.zig");
+const OffsetFile = @import("util/offset_file.zig");
+const SharedCache = @import("util/shared_cache.zig");
+const XattrTable = @import("xattr_table.zig");
 
-pub const Ref = packed struct {
-    offset: u16,
-    block: u32,
-    _: u16,
+const Inode = @This();
+
+hdr: Header,
+data: Data,
+
+pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !Inode {
+    var hdr: Header = undefined;
+    try rdr.readSliceEndian(Header, @ptrCast(&hdr), .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) },
+        },
+    };
+}
+pub fn deinit(self: Inode, alloc: std.mem.Allocator) void {
+    switch (self.data) {
+        .file => |d| d.deinit(alloc),
+        .symlink => |d| d.deinit(alloc),
+        .ext_file => |d| d.deinit(alloc),
+        .ext_symlink => |d| d.deinit(alloc),
+        else => {},
+    }
+}
+
+// Utility Functions
+
+/// Read the directory entries
+pub fn readDirectory(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, dir_offset: u64) ![]DirEntry {
+    return switch (self.data) {
+        .dir => |d| readDirFromData(alloc, io, fil, decomp, dir_offset, d),
+        .ext_dir => |d| readDirFromData(alloc, io, fil, decomp, dir_offset, d),
+        else => Error.NotDirectory,
+    };
+}
+fn readDirFromData(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, dir_offset: u64, d: anytype) ![]DirEntry {
+    var rdr = try fil.readerAt(io, dir_offset + d.block_start, &[0]u8{});
+    var meta: MetadataReader = .init(alloc, &rdr.interface, decomp);
+    try meta.interface.discardAll(d.block_offset);
+
+    return DirEntry.readDirectory(alloc, &meta.interface, d.size);
+}
+/// Get a reader for a regular file's data.
+pub fn dataReader(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32) !DataReader {
+    return switch (self.data) {
+        .file => |f| getReaderFromData(alloc, io, fil, cache, decomp, block_size, f),
+        .ext_file => |f| getReaderFromData(alloc, io, fil, cache, decomp, block_size, f),
+        else => Error.NotRegularFile,
+    };
+}
+fn getReaderFromData(alloc: std.mem.Allocator, io: Io, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32, d: anytype) !DataReader {
+    const ext: DataReader = .init(alloc, io, fil, cache, decomp, block_size, d.size, d.block_start, d.blocks);
+    if (d.frag_block_offset == 0xFFFFFFFF) {
+        // TODO:
+        return error.TODO;
+    }
+    return ext;
+}
+/// Get an extractor for a regular file's data.
+pub fn dataExtractor(self: Inode, fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32) !DataExtractor {
+    return switch (self.data) {
+        .file => |f| getExtractorFromData(fil, cache, decomp, block_size, f),
+        .ext_file => |f| getExtractorFromData(fil, cache, decomp, block_size, f),
+        else => Error.NotRegularFile,
+    };
+}
+fn getExtractorFromData(fil: OffsetFile, cache: *SharedCache, decomp: *const Decompressor, block_size: u32, d: anytype) !DataExtractor {
+    const ext: DataExtractor = .init(fil, cache, decomp, block_size, d.size, d.block_start, d.blocks);
+    if (d.frag_block_offset == 0xFFFFFFFF) {
+        // TODO:
+        return error.TODO;
+    }
+    return ext;
+}
+/// Get a symlink's target path
+pub fn symlinkTarget(self: Inode) ![]const u8 {
+    return switch (self.data) {
+        .symlink => |s| s.target,
+        .ext_symlink => |s| s.target,
+        else => Error.NotSymlink,
+    };
+}
+/// Get inode's gid
+pub fn gid(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, id_table_start: u64) !u16 {
+    return LookupTable.lookupValue(u16, alloc, io, decomp, fil, id_table_start, self.hdr.gid_idx);
+}
+/// Get inode's uid
+pub fn uid(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, id_table_start: u64) !u16 {
+    return LookupTable.lookupValue(u16, alloc, io, decomp, fil, id_table_start, self.hdr.uid_idx);
+}
+/// Get the inode's xattr values as an index into the Archive's xattr table.
+/// Returns error.NoXattr if the inode doesn't have extended attributes.
+pub fn xattrIndex(self: Inode) !u32 {
+    const idx = switch (self.data) {
+        .ext_dir => |e| e.xattr_idx,
+        .ext_file => |e| e.xattr_idx,
+        .ext_symlink => |e| e.xattr_idx,
+        .ext_block_dev => |e| e.xattr_idx,
+        .ext_char_dev => |e| e.xattr_idx,
+        .ext_fifo => |e| e.xattr_idx,
+        .ext_socket => |e| e.xattr_idx,
+        else => Error.NoXattr,
+    };
+    if (idx == 0xFFFFFFFF) return Error.NoXattr;
+    return idx;
+}
+// Get an inode's xattr values. If the inode does not have xattr values (including if the inode is not an extended type), an empty slice is returned.
+pub fn xattrValues(self: Inode, alloc: std.mem.Allocator, io: Io, fil: OffsetFile, decomp: *const Decompressor, xattr_table_start: u64) ![]XattrTable.XattrOwned {
+    const idx = self.xattrIndex() catch &[0]XattrTable.XattrOwned{};
+    return XattrTable.statelessLookup(alloc, io, decomp, fil, xattr_table_start, idx);
+}
+
+// Types
+
+pub const Error = error{
+    NotDirectory,
+    NotRegularFile,
+    NotSymlink,
+    NotExtended,
+};
+
+pub const Ref = packed struct(u64) {
+    block_offset: u16,
+    block_start: u32,
+    _: u16 = 0,
 };
 
 pub const Type = enum(u16) {
@@ -27,16 +179,7 @@ pub const Type = enum(u16) {
     ext_socket,
 };
 
-pub const Header = packed struct {
-    type: Type,
-    perm: u16,
-    uid_idx: u16,
-    gid_idx: u16,
-    mod_time: u32,
-    num: u32,
-};
-
-pub const Data = union(enum) {
+pub const Data = union(Type) {
     dir: dir.Dir,
     file: file.File,
     symlink: misc.Symlink,
@@ -53,41 +196,317 @@ pub const Data = union(enum) {
     ext_socket: misc.ExtIPC,
 };
 
-const Self = @This();
+pub const Header = extern struct {
+    inode_type: Type,
+    permissions: u16,
+    uid_idx: u16,
+    gid_idx: u16,
+    mod_time: u32,
+    num: u32,
+};
 
-hdr: Header,
-data: Data,
+// Extract
 
-pub fn init(rdr: anytype, alloc: std.mem.Allocator, block_size: u32) !Self {
-    var hdr: Header = undefined;
-    _ = try rdr.read(std.mem.asBytes(&hdr));
-    const data: Data = switch (hdr.type) {
-        .dir => .{ .dir = try .init(rdr) },
-        .file => .{ .file = try .init(rdr, alloc, block_size) },
-        .symlink => .{ .symlink = try .init(rdr, alloc) },
-        .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(rdr, alloc, block_size) },
-        .ext_symlink => .{ .ext_symlink = try .init(rdr, alloc) },
-        .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) },
+const ExtractError = error{ MknodFailed, CannotSetXattr, ConcurrencyUnavailable } || DataExtractor.Error || Io.Dir.CreateFileAtomicError || LookupTable.Error ||
+    Io.File.Reader.SeekError || Io.File.Atomic.LinkError || Io.Dir.CreateDirError || Io.File.OpenError ||
+    Io.File.SetPermissionsError || Io.File.SetOwnerError || Io.Dir.SymLinkError || Io.Dir.CreateDirPathError;
+const PathRet = struct {
+    path: []const u8,
+    inode: Inode,
+    xattr_idx: ?u32 = null,
+};
+const ExtractReturnUnion = union(enum) {
+    path_ret: ExtractError!PathRet,
+};
+const Tables = struct {
+    id: LookupTable.CachedTable(u16),
+    frag: LookupTable.CachedTable(FragEntry),
+    xattr: XattrTable,
+};
+
+/// Extracts the given inode to the given path. If the inode not a directory, the given path must not exist.
+/// If the inode is a directory the path must not exist or be a directory.
+pub fn extract(
+    self: Inode,
+    alloc: std.mem.Allocator,
+    io: Io,
+    fil: OffsetFile,
+    super: Archive.Superblock,
+    filepath: []const u8,
+    options: ExtractionOptions,
+) !void {
+    const path = std.mem.trimEnd(u8, filepath, "/");
+
+    var decomp_base: Decomp = switch (super.compression) {
+        .gzip => .{ .gzip = try .init(alloc, super.block_size) },
+        .lzma => .{ .lzma = try .init(alloc, super.block_size) },
+        .xz => .{ .xz = try .init(alloc, super.block_size) },
+        .zstd => .{ .zstd = try .init(alloc, io, super.block_size) },
+        else => unreachable,
     };
-    return .{
-        .hdr = hdr,
-        .data = data,
-    };
-}
-pub fn deinit(self: Self, 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 => {},
+    defer decomp_base.deinit();
+    const decomp = decomp_base.decompressor();
+
+    var frag_table: CachedTable(FragEntry) = .init(alloc, fil, decomp, super.frag_start, super.frag_count);
+    defer if (!options.ignore_permissions) frag_table.deinit(io);
+    try frag_table.fill(io);
+
+    var arena: std.heap.ArenaAllocator = .init(alloc);
+    defer arena.deinit();
+
+    var sel_buf = [1]ExtractReturnUnion{undefined} ** 10;
+    var sel: Io.Select(ExtractReturnUnion) = .init(io, &sel_buf);
+    defer sel.cancelDiscard();
+
+    switch (self.hdr.inode_type) {
+        .dir, .ext_dir => try sel.concurrent(
+            .path_ret,
+            extractDir,
+            .{ self, alloc, io, fil, decomp, &sel, &arena, super.dir_start, super.inode_start, &frag_table, super.block_size, path },
+        ),
+        .file, .ext_file => try sel.concurrent(
+            .path_ret,
+            extractFile,
+            .{ self, alloc, io, fil, decomp, &frag_table, super.block_size, path },
+        ),
+        .symlink, .ext_symlink => try sel.concurrent(.path_ret, extractSymlink, .{ self, io, path }),
+        else => if (@hasField(std.os, "linux"))
+            try sel.concurrent(.path_ret, extractDevOrIPC, .{ self, alloc, path }),
+    }
+
+    var xattr_table: ?XattrTable = if (!options.ignore_xattr)
+        try .init(alloc, io, fil, decomp, super.xattr_start)
+    else
+        null;
+    defer if (!options.ignore_xattr) xattr_table.?.deinit(io);
+    if (xattr_table != null) try xattr_table.?.table.fill(io);
+
+    var id_table: ?CachedTable(u16) = if (!options.ignore_xattr)
+        .init(alloc, fil, decomp, super.id_start, super.id_count)
+    else
+        null;
+    defer if (!options.ignore_xattr) id_table.?.deinit(io);
+    if (id_table != null) try id_table.?.fill(io);
+
+    while (true) {
+        const group_token = sel.group.token.load(.acquire);
+        if (group_token == null) break;
+        // std.debug.print("{any}\n", .{sel.group.state});
+
+        // std.debug.print("Waiting for return...", .{});
+        const ret = try sel.await();
+        // std.debug.print("Got One...\n", .{});
+        const path_ret = try ret.path_ret;
+
+        if (options.ignore_permissions and options.ignore_xattr) continue;
+        if (options.ignore_permissions and path_ret.xattr_idx == null) continue;
+
+        var ret_file = try Io.Dir.cwd().openFile(io, path_ret.path, .{});
+        defer ret_file.close(io);
+
+        if (!options.ignore_permissions) {
+            try ret_file.setPermissions(io, @enumFromInt(path_ret.inode.hdr.permissions));
+            try ret_file.setOwner(
+                io,
+                try id_table.?.get(io, path_ret.inode.hdr.uid_idx),
+                try id_table.?.get(io, path_ret.inode.hdr.gid_idx),
+            );
+        }
+        if (@hasField(std.os, "linux") and !options.ignore_xattr and path_ret.xattr_idx != null) {
+            const xattrs = try xattr_table.?.get(alloc, io, path_ret.xattr_idx.?);
+            defer {
+                for (xattrs) |x|
+                    alloc.free(x.key);
+                alloc.free(xattrs);
+            }
+
+            for (xattrs) |x| {
+                const res = std.os.linux.fsetxattr(ret_file.handle, x.key, x.value.ptr, x.value.len, 0);
+                if (res != 0)
+                    return error.CannotSetXattr;
+            }
+        }
     }
 }
+fn extractDir(
+    self: Inode,
+    alloc: std.mem.Allocator,
+    io: Io,
+    fil: OffsetFile,
+    decomp: *const Decompressor,
+    parent_select: *Io.Select(ExtractReturnUnion),
+    arena: *std.heap.ArenaAllocator,
+    dir_start: u64,
+    inode_start: u64,
+    frag: *CachedTable(FragEntry),
+    block_size: u32,
+    path: []const u8,
+) ExtractError!PathRet {
+    try Io.Dir.cwd().createDirPath(io, path);
+
+    var sel_buf = [1]ExtractReturnUnion{undefined} ** 10;
+    var sel: Io.Select(ExtractReturnUnion) = .init(io, &sel_buf);
+    defer sel.cancelDiscard();
+
+    var num: usize = 0;
+    {
+        const dir_entries = self.readDirectory(alloc, io, fil, decomp, dir_start) catch |err| switch (err) {
+            Error.NotDirectory => unreachable,
+            else => return @errorCast(err),
+        };
+        num = dir_entries.len;
+        defer {
+            for (dir_entries) |d|
+                d.deinit(alloc);
+            alloc.free(dir_entries);
+        }
+
+        for (dir_entries) |d| {
+            var rdr = try fil.readerAt(io, d.block_start + inode_start, &[0]u8{});
+            var meta_rdr: MetadataReader = .init(alloc, &rdr.interface, decomp);
+            try meta_rdr.interface.discardAll(d.block_offset);
+            const inode = try read(arena.allocator(), &meta_rdr.interface, block_size);
+            errdefer inode.deinit(arena.allocator());
+
+            const new_path = try std.mem.concat(arena.allocator(), u8, &[_][]const u8{ path, "/", d.name });
+            errdefer arena.allocator().free(new_path);
+
+            switch (d.type) {
+                .dir => try sel.concurrent(
+                    .path_ret,
+                    extractDir,
+                    .{ inode, alloc, io, fil, decomp, parent_select, arena, dir_start, inode_start, frag, block_size, new_path },
+                ),
+                .file => try sel.concurrent(
+                    .path_ret,
+                    extractFile,
+                    .{ inode, alloc, io, fil, decomp, frag, block_size, new_path },
+                ),
+                .symlink => try sel.concurrent(.path_ret, extractSymlink, .{ inode, io, new_path }),
+                else => try sel.concurrent(.path_ret, extractDevOrIPC, .{ inode, alloc, new_path }),
+            }
+        }
+    }
+
+    while (num > 0) {
+        const ret = sel.await() catch break;
+        num -= 1;
+
+        parent_select.queue.putOne(io, ret) catch |err| switch (err) {
+            error.Canceled => return error.Canceled,
+            else => break,
+        };
+    }
+    return .{
+        .path = path,
+        .inode = self,
+    };
+}
+fn extractFile(
+    self: Inode,
+    alloc: std.mem.Allocator,
+    io: Io,
+    fil: OffsetFile,
+    decomp: *const Decompressor,
+    frag: *CachedTable(FragEntry),
+    block_size: u32,
+    path: []const u8,
+) ExtractError!PathRet {
+    var atomic = try Io.Dir.cwd().createFileAtomic(io, path, .{});
+    defer atomic.deinit(io);
+
+    var ret: PathRet = .{
+        .inode = self,
+        .path = path,
+    };
+    const data: DataExtractor = blk: {
+        switch (self.data) {
+            .file => |f| {
+                var data: DataExtractor = .init(fil, decomp, block_size, f.size, f.block_start, f.block_sizes);
+                if (f.frag_idx != 0xFFFFFFFF)
+                    data.addFrag(f.frag_block_offset, try frag.get(io, f.frag_idx));
+
+                break :blk data;
+            },
+            .ext_file => |f| {
+                if (f.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = f.xattr_idx;
+                var data: DataExtractor = .init(fil, decomp, block_size, f.size, f.block_start, f.block_sizes);
+                if (f.frag_idx != 0xFFFFFFFF)
+                    data.addFrag(f.frag_block_offset, try frag.get(io, f.frag_idx));
+
+                break :blk data;
+            },
+            else => unreachable,
+        }
+    };
+
+    try data.extractAsync(alloc, io, atomic.file);
+    try atomic.link(io);
+
+    return ret;
+}
+fn extractSymlink(self: Inode, io: Io, path: []const u8) ExtractError!PathRet {
+    const target = switch (self.data) {
+        .symlink => |s| s.target,
+        .ext_symlink => |s| s.target,
+        else => unreachable,
+    };
+
+    try Io.Dir.cwd().symLink(io, target, path, .{});
+
+    return .{
+        .path = path,
+        .inode = self,
+    };
+}
+fn extractDevOrIPC(self: Inode, alloc: std.mem.Allocator, path: []const u8) ExtractError!PathRet {
+    var dev_num: u32 = 0;
+    var mode: u32 = 0;
+
+    const DT = std.posix.DT;
+
+    var ret: PathRet = .{
+        .inode = self,
+        .path = path,
+    };
+
+    switch (self.data) {
+        .block_dev => |d| {
+            dev_num = d.dev;
+            mode = DT.BLK;
+        },
+        .ext_block_dev => |d| {
+            dev_num = d.dev;
+            mode = DT.BLK;
+            if (d.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = d.xattr_idx;
+        },
+        .char_dev => |d| {
+            dev_num = d.dev;
+            mode = DT.CHR;
+        },
+        .ext_char_dev => |d| {
+            dev_num = d.dev;
+            mode = DT.CHR;
+            if (d.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = d.xattr_idx;
+        },
+        .fifo => mode = DT.FIFO,
+        .ext_fifo => |f| {
+            mode = DT.FIFO;
+            if (f.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = f.xattr_idx;
+        },
+        .socket => mode = DT.SOCK,
+        .ext_socket => |s| {
+            mode = DT.SOCK;
+            if (s.xattr_idx != 0xFFFFFFFF) ret.xattr_idx = s.xattr_idx;
+        },
+        else => unreachable,
+    }
+
+    const sentinel_path = try std.mem.concatWithSentinel(alloc, u8, &[_][]const u8{path}, 0);
+    defer alloc.free(sentinel_path);
+
+    const res = std.os.linux.mknod(sentinel_path, mode, dev_num);
+    if (res != 0) return ExtractError.MknodFailed;
+
+    return ret;
+}

src/inode/dir.zig

@@ -1,31 +0,0 @@
-const std = @import("std");
-
-pub const Dir = packed struct {
-    block: u32,
-    hard_link: u32,
-    size: u16,
-    offset: u16,
-    parent_num: u32,
-
-    pub fn init(rdr: anytype) !Dir {
-        var out: Dir = undefined;
-        _ = try rdr.read(std.mem.asBytes(&out));
-        return out;
-    }
-};
-
-pub const ExtDir = packed struct {
-    hard_link: u32,
-    size: u32,
-    block: u32,
-    parent_num: u32,
-    idx_count: u16,
-    offset: u16,
-    xattr_idx: u32,
-
-    pub fn init(rdr: anytype) !ExtDir {
-        var out: ExtDir = undefined;
-        _ = try rdr.read(std.mem.asBytes(&out));
-        return out;
-    }
-};

src/inode/file.zig

@@ -1,77 +0,0 @@
-const std = @import("std");
-
-pub const BlockSize = packed struct {
-    size: u24,
-    uncompressed: bool,
-    _: u7,
-};
-
-pub const File = struct {
-    block: u32,
-    frag_idx: u32,
-    frag_offset: u32,
-    size: u32,
-    block_sizes: []BlockSize,
-
-    pub fn init(rdr: anytype, alloc: std.mem.Allocator, block_size: u32) !File {
-        var fixed: [16]u8 = undefined;
-        _ = try rdr.read(&fixed);
-        const frag_idx = std.mem.readInt(u32, fixed[4..8], .little);
-        const size = std.mem.readInt(u32, fixed[12..16], .little);
-        var blocks: u32 = size / block_size;
-        if (size % block_size > 0 and frag_idx == 0xffffffff) {
-            blocks += 1;
-        }
-        const block_sizes = try alloc.alloc(BlockSize, blocks);
-        errdefer alloc.free(block_sizes);
-        _ = try rdr.read(std.mem.sliceAsBytes(block_sizes));
-        return .{
-            .block = std.mem.readInt(u32, fixed[0..4], .little),
-            .frag_idx = frag_idx,
-            .frag_offset = std.mem.readInt(u32, fixed[8..12], .little),
-            .size = size,
-            .block_sizes = block_sizes,
-        };
-    }
-    pub fn hasFragment(self: File) bool {
-        return self.frag_idx != 0xffffffff;
-    }
-};
-
-pub const ExtFile = struct {
-    block: u64,
-    size: u64,
-    sparse: u64,
-    hard_link: u32,
-    frag_idx: u32,
-    frag_offset: u32,
-    xattr_idx: u32,
-    block_sizes: []BlockSize,
-
-    pub fn init(rdr: anytype, alloc: std.mem.Allocator, block_size: u32) !ExtFile {
-        var fixed: [40]u8 = undefined;
-        _ = try rdr.read(&fixed);
-        const size = std.mem.readInt(u64, fixed[8..16], .little);
-        const frag_idx = std.mem.readInt(u32, fixed[28..32], .little);
-        var blocks: u32 = @truncate(size / block_size);
-        if (size % block_size > 0 and frag_idx == 0xffffffff) {
-            blocks += 1;
-        }
-        const block_sizes = try alloc.alloc(BlockSize, blocks);
-        errdefer alloc.free(block_sizes);
-        _ = try rdr.read(std.mem.sliceAsBytes(block_sizes));
-        return .{
-            .block = std.mem.readInt(u64, fixed[0..8], .little),
-            .size = size,
-            .sparse = std.mem.readInt(u64, fixed[16..24], .little),
-            .hard_link = std.mem.readInt(u32, fixed[24..28], .little),
-            .frag_idx = frag_idx,
-            .frag_offset = std.mem.readInt(u32, fixed[32..36], .little),
-            .xattr_idx = std.mem.readInt(u32, fixed[36..40], .little),
-            .block_sizes = block_sizes,
-        };
-    }
-    pub fn hasFragment(self: ExtFile) bool {
-        return self.frag_idx != 0xffffffff;
-    }
-};

src/inode/misc.zig

@@ -1,87 +0,0 @@
-const std = @import("std");
-
-pub const Symlink = struct {
-    hard_link: u32,
-    // size: u32,
-    target: []const u8,
-
-    pub fn init(rdr: anytype, alloc: std.mem.Allocator) !Symlink {
-        var fixed: [8]u8 = undefined;
-        _ = try rdr.read(&fixed);
-        const size = std.mem.readInt(u32, fixed[4..8], .little);
-        const target = try alloc.alloc(u8, size);
-        errdefer alloc.free(target);
-        _ = try rdr.read(target);
-        return .{
-            .hard_link = std.mem.readInt(u32, fixed[0..4], .little),
-            .target = target,
-        };
-    }
-};
-
-pub const ExtSymlink = struct {
-    hard_link: u32,
-    // size: u32,
-    target: []const u8,
-    xattr_idx: u32,
-
-    pub fn init(rdr: anytype, alloc: std.mem.Allocator) !ExtSymlink {
-        var fixed: [8]u8 = undefined;
-        _ = try rdr.read(&fixed);
-        const size = std.mem.readInt(u32, fixed[4..8], .little);
-        const target = try alloc.alloc(u8, size);
-        errdefer alloc.free(target);
-        _ = try rdr.read(target);
-        var xattr_idx: u32 = 0;
-        _ = try rdr.read(std.mem.asBytes(&xattr_idx));
-        return .{
-            .hard_link = std.mem.readInt(u32, fixed[0..4], .little),
-            .target = target,
-            .xattr_idx = xattr_idx,
-        };
-    }
-};
-
-pub const Dev = packed struct {
-    hard_link: u32,
-    device: u32,
-
-    pub fn init(rdr: anytype) !Dev {
-        var out: Dev = undefined;
-        _ = try rdr.read(std.mem.asBytes(&out));
-        return out;
-    }
-};
-
-pub const ExtDev = packed struct {
-    hard_link: u32,
-    device: u32,
-    xattr_idx: u32,
-
-    pub fn init(rdr: anytype) !ExtDev {
-        var out: ExtDev = undefined;
-        _ = try rdr.read(std.mem.asBytes(&out));
-        return out;
-    }
-};
-
-pub const IPC = packed struct {
-    hard_link: u32,
-
-    pub fn init(rdr: anytype) !IPC {
-        var out: IPC = undefined;
-        _ = try rdr.read(std.mem.asBytes(&out));
-        return out;
-    }
-};
-
-pub const ExtIPC = packed struct {
-    hard_link: u32,
-    xattr_idx: u32,
-
-    pub fn init(rdr: anytype) !ExtIPC {
-        var out: ExtIPC = undefined;
-        _ = try rdr.read(std.mem.asBytes(&out));
-        return out;
-    }
-};

src/inode_data/dir.zig

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

src/inode_data/file.zig

@@ -0,0 +1,97 @@
+const std = @import("std");
+const Reader = std.Io.Reader;
+
+pub const BlockSize = packed struct(u32) {
+    size: u24,
+    uncompressed: bool,
+    _: u7,
+};
+
+const FileRawRead = extern struct {
+    block_start: u32,
+    frag_idx: u32,
+    frag_block_offset: u32,
+    size: u32,
+};
+
+pub const File = struct {
+    block_start: u32,
+    frag_idx: u32,
+    frag_block_offset: u32,
+    size: u32,
+    block_sizes: []BlockSize,
+
+    pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !File {
+        var raw: FileRawRead = undefined;
+        try rdr.readSliceEndian(FileRawRead, @ptrCast(&raw), .little);
+
+        var num_blocks: u32 = raw.size / block_size;
+        if (raw.size % block_size != 0 and raw.frag_idx == 0xFFFFFFFF)
+            num_blocks += 1;
+
+        const sizes = try alloc.alloc(BlockSize, num_blocks);
+        errdefer alloc.free(sizes);
+        try rdr.readSliceEndian(BlockSize, sizes, .little);
+
+        return .{
+            .block_start = raw.block_start,
+            .frag_idx = raw.frag_idx,
+            .frag_block_offset = raw.frag_block_offset,
+            .size = raw.size,
+            .block_sizes = sizes,
+        };
+    }
+
+    pub fn deinit(self: File, alloc: std.mem.Allocator) void {
+        alloc.free(self.block_sizes);
+    }
+};
+
+const ExtFileRawRead = extern struct {
+    block_start: u64,
+    size: u64,
+    sparse: u64,
+    hard_links: u32,
+    frag_idx: u32,
+    frag_block_offset: u32,
+    xattr_idx: u32,
+};
+
+pub const ExtFile = struct {
+    block_start: u64,
+    size: u64,
+    sparse: u64,
+    hard_links: u32,
+    frag_idx: u32,
+    frag_block_offset: u32,
+    xattr_idx: u32,
+    block_sizes: []BlockSize,
+
+    pub fn read(alloc: std.mem.Allocator, rdr: *Reader, block_size: u32) !ExtFile {
+        var raw: ExtFileRawRead = undefined;
+        try rdr.readSliceEndian(ExtFileRawRead, @ptrCast(&raw), .little);
+
+        var num_blocks: u32 = @truncate(raw.size / block_size);
+        if (raw.size % block_size != 0 and raw.frag_idx == 0xFFFFFFFF)
+            num_blocks += 1;
+
+        const sizes = try alloc.alloc(BlockSize, num_blocks);
+        errdefer alloc.free(sizes);
+        try rdr.readSliceEndian(BlockSize, sizes, .little);
+
+        return .{
+            .block_start = raw.block_start,
+            .size = raw.size,
+            .sparse = raw.sparse,
+            .hard_links = raw.hard_links,
+            .frag_idx = raw.frag_idx,
+            .frag_block_offset = raw.frag_block_offset,
+            .xattr_idx = raw.xattr_idx,
+            .block_sizes = sizes,
+        };
+    }
+
+    pub fn deinit(self: ExtFile, alloc: std.mem.Allocator) void {
+        alloc.free(self.block_sizes);
+    }
+};

src/inode_data/misc.zig

@@ -0,0 +1,98 @@
+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 = extern 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 = extern 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 = extern 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 = extern 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_table.zig

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

src/options.zig

@@ -0,0 +1,33 @@
+//! Options for file/directory extraction.
+
+const std = @import("std");
+const Writer = std.Io.Writer;
+
+const ExtractionOptions = @This();
+
+/// The number of threads used for extraction. 0 implies single threaded.
+threads: usize = 1, // TODO: Update to better integrate with zig 0.16 Io. Maybe limit to only single or multi-threaded.
+/// Don't set the file's owner & permissions after extraction
+ignore_permissions: bool = false,
+/// Don't set xattr values. Currently xattrs are never set anyway.
+ignore_xattr: bool = false,
+/// Replace symlinks with their target.
+dereference_symlinks: bool = false,
+/// Verbose logging. If true, verbose_writer must be set
+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 fn VerboseDefault(wrt: *Writer) !ExtractionOptions {
+    return .{
+        .verbose = true,
+        .verbose_writer = wrt,
+        .threads = try std.Thread.getCpuCount(),
+    };
+}

src/reader.zig

@@ -1,85 +0,0 @@
-const std = @import("std");
-
-const Inode = @import("inode.zig");
-const File = @import("file.zig").File;
-const Table = @import("table.zig").Table;
-const PRead = @import("reader/p_read.zig").PRead;
-const FragEntry = @import("fragment.zig").FragEntry;
-const Superblock = @import("superblock.zig").Superblock;
-const ExtractionOptions = @import("extract_options.zig");
-const MetadataReader = @import("reader/metadata.zig").MetadataReader;
-
-pub const SfsError = error{
-    NotExportable,
-};
-
-pub fn SfsReader(comptime T: type) type {
-    comptime std.debug.assert(std.meta.hasFn(T, "pread"));
-
-    return struct {
-        const Self = @This();
-
-        alloc: std.mem.Allocator,
-        rdr: PRead(T),
-
-        super: Superblock = undefined,
-        /// ID table. Can be accessed directly
-        id_table: Table(u32, T) = undefined,
-        /// Fragment table. Can be accessed directly
-        frag_table: Table(FragEntry, T) = undefined,
-        /// Export table. Each element is an inode referce.
-        /// If accessing directly, keep in mind, the table starts at inode 1, as such it's recommended to use the InodeAt function instead.
-        export_table: Table(Inode.Ref, T) = undefined,
-
-        pub fn init(alloc: std.mem.Allocator, rdr: T, offset: u64) !Self {
-            var out: Self = .{
-                .alloc = alloc,
-                .rdr = .init(rdr, offset),
-            };
-            _ = try rdr.pread(std.mem.asBytes(&out.super), 0);
-            out.frag_table = .init(alloc, out.rdr, out.super.comp, out.super.frag_start, out.super.frag_count);
-            out.id_table = .init(alloc, out.rdr, out.super.comp, out.super.id_start, out.super.id_count);
-            out.export_table = .init(alloc, out.rdr, out.super.comp, out.super.export_start, out.super.inode_count);
-            return out;
-        }
-        pub fn deinit(self: *Self) void {
-            self.id_table.deinit();
-            self.frag_table.deinit();
-            self.export_table.deinit();
-        }
-
-        /// A representation of the archives root folder.
-        pub fn root(self: *Self) !File(T) {
-            return .initFromRef(self, self.super.root_ref, "");
-        }
-        /// Get the file at path. Equivelent to calling open on the root File.
-        pub fn open(self: *Self, path: []const u8) !File(T) {
-            var rt = try self.root();
-            if (path.len == 0 or (path.len == 1 and path[0] == '/') or path.len == 1 and path[0] == '.') return rt;
-            defer rt.deinit();
-            return rt.open(path);
-        }
-        /// Extract the entire archive to the given path & with the given options.
-        /// Equivelent to calling extract on the root File.
-        pub fn extract(self: *Self, op: ExtractionOptions, path: []const u8) !void {
-            var rt = try self.root();
-            defer rt.deinit();
-            return rt.extract(op, path);
-        }
-
-        /// Returns the Inode with the given Inode Number.
-        /// Requires the archive to have an export table.
-        pub fn inodeAt(self: Self, num: u32) !Inode {
-            if (!self.super.flags.has_export) return SfsError.NotExportable;
-            const ref = try self.export_table.get(num - 1);
-            var meta = MetadataReader(T).init(
-                self.alloc,
-                self.super.comp,
-                self.rdr,
-                self.super.inode_start + ref.block,
-            );
-            try meta.skip(ref.offset);
-            return .init(meta, self.alloc, self.super.block_size);
-        }
-    };
-}

src/reader/data.zig

@@ -1,271 +0,0 @@
-const std = @import("std");
-
-const Inode = @import("../inode.zig");
-const PRead = @import("p_read.zig").PRead;
-const SfsReader = @import("../reader.zig").SfsReader;
-const FragEntry = @import("../fragment.zig").FragEntry;
-const BlockSize = @import("../inode/file.zig").BlockSize;
-const Compression = @import("../superblock.zig").Compression;
-
-const DataReaderError = error{
-    EOF,
-    InvalidIndex,
-    ExtractionActive,
-};
-
-const DecompCompletion = struct {
-    errs: std.ArrayList(anyerror),
-    map: std.AutoArrayHashMap(usize, []u8),
-    mut: std.Thread.Mutex = .{},
-    cond: std.Thread.Condition = .{},
-
-    fn init(alloc: std.mem.Allocator) DecompCompletion {
-        return .{
-            .errs = .init(alloc),
-            .map = .init(alloc),
-        };
-    }
-    fn deinit(self: *DecompCompletion) void {
-        self.errs.deinit();
-        self.map.deinit();
-    }
-
-    fn clear(self: *DecompCompletion) void {
-        self.mut.lock();
-        defer self.mut.unlock();
-        self.errs.clearAndFree();
-        self.map.clearAndFree();
-    }
-
-    fn add(self: *DecompCompletion, idx: usize, data: []u8) !void {
-        self.mut.lock();
-        defer self.mut.unlock();
-        defer self.cond.signal();
-        try self.map.put(idx, data);
-    }
-    fn addErr(self: *DecompCompletion, err: anyerror) void {
-        self.mut.lock();
-        defer self.mut.unlock();
-        defer self.cond.signal();
-        self.errs.append(err) catch {};
-    }
-
-    fn getBlock(self: *DecompCompletion, idx: usize) ?[]u8 {
-        const res = self.map.fetchSwapRemove(idx);
-        if (res == null) return null;
-        return res.?.value;
-    }
-    fn hasErrs(self: DecompCompletion) bool {
-        return self.errs.items.len > 0;
-    }
-    fn condWait(self: *DecompCompletion) void {
-        self.cond.wait(&self.mut);
-    }
-};
-
-pub fn DataReader(comptime T: type) type {
-    return struct {
-        const Self = @This();
-
-        alloc: std.mem.Allocator,
-        rdr: PRead(T),
-        comp: Compression,
-        block_size: u32,
-
-        sizes: []BlockSize,
-        offsets: []u64,
-        file_size: u64,
-
-        frag: ?[]u8 = null,
-
-        completion: DecompCompletion,
-
-        pub fn init(rdr: *SfsReader(T), inode: Inode) !Self {
-            var sizes: []BlockSize = undefined;
-            var file_size: u64 = 0;
-            var offsets: []u64 = undefined;
-            switch (inode.data) {
-                .file => |f| {
-                    sizes = f.block_sizes;
-                    file_size = f.size;
-                    offsets = try rdr.alloc.alloc(u64, sizes.len);
-                    if (sizes.len > 0) offsets[0] = f.block;
-                },
-                .ext_file => |f| {
-                    sizes = f.block_sizes;
-                    file_size = f.size;
-                    offsets = try rdr.alloc.alloc(u64, sizes.len);
-                    if (sizes.len > 0) offsets[0] = f.block;
-                },
-                else => unreachable,
-            }
-            if (offsets.len > 1) {
-                for (1..offsets.len) |i| {
-                    offsets[i] = offsets[i - 1] + sizes[i - 1].size;
-                }
-            }
-            return .{
-                .alloc = rdr.alloc,
-                .rdr = rdr.rdr,
-                .comp = rdr.super.comp,
-                .block_size = rdr.super.block_size,
-                .sizes = sizes,
-                .offsets = offsets,
-                .file_size = file_size,
-                .completion = .init(rdr.alloc),
-            };
-        }
-        pub fn deinit(self: *Self) void {
-            self.alloc.free(self.offsets);
-            self.completion.deinit();
-        }
-
-        pub fn addFragment(self: *Self, data: []u8) void {
-            self.frag = data;
-        }
-
-        pub fn writeTo(self: *Self, wrt: anytype) !void {
-            comptime std.debug.assert(std.meta.hasFn(@TypeOf(wrt), "write") or std.meta.hasFn(@TypeOf(wrt), "pwrite"));
-            var write_thr = try std.Thread.spawn(
-                .{ .allocator = self.alloc },
-                writeThread,
-                .{ self, wrt, null, null },
-            );
-            defer self.completion.clear();
-            for (0..self.numBlocks()) |i| {
-                var thr = std.Thread.spawn(
-                    .{ .allocator = self.alloc },
-                    decompThread,
-                    .{ self, i },
-                ) catch |err| {
-                    self.completion.addErr(err);
-                    continue;
-                };
-                thr.detach();
-            }
-            write_thr.join();
-            if (self.completion.hasErrs()) return self.completion.errs.items[0];
-        }
-
-        pub fn writeToNoBlock(self: *Self, wrt: anytype, comptime finish: anytype, finish_args: anytype) !void {
-            comptime std.debug.assert(std.meta.hasFn(@TypeOf(wrt), "write") or std.meta.hasFn(@TypeOf(wrt), "pwrite"));
-            errdefer self.completion.clear();
-            var write_thr = try std.Thread.spawn(
-                .{ .allocator = self.alloc },
-                writeThread,
-                .{ self, wrt, finish, finish_args },
-            );
-            write_thr.detach();
-            for (0..self.numBlocks()) |i| {
-                var thr = std.Thread.spawn(
-                    .{ .allocator = self.alloc },
-                    decompThread,
-                    .{ self, i },
-                ) catch |err| {
-                    self.completion.addErr(err);
-                    continue;
-                };
-                thr.detach();
-            }
-        }
-
-        fn numBlocks(self: Self) usize {
-            var out = self.sizes.len;
-            if (self.frag != null) out += 1;
-            return out;
-        }
-        /// Returns the decompressed data block at the given idx.
-        /// If the block is sparse (filled with 0s), a zero length slice is returned.
-        fn blockAt(self: Self, idx: usize) ![]u8 {
-            if (idx >= self.numBlocks()) return DataReaderError.InvalidIndex;
-            const size = self.sizes[idx];
-            if (size.size == 0) return &[0]u8{};
-            const block = try self.alloc.alloc(u8, blk: {
-                if (idx == self.numBlocks() - 1) break :blk self.file_size % self.block_size;
-                break :blk self.block_size;
-            });
-            if (idx == self.sizes.len and self.frag != null) {
-                @memcpy(block, self.frag.?);
-                return block;
-            }
-            if (size.uncompressed) {
-                _ = try self.rdr.pread(block, self.offsets[idx]);
-                return block;
-            }
-            _ = try self.comp.decompress(
-                1024 * 1024,
-                self.alloc,
-                self.rdr.readerAt(self.offsets[idx]).reader(),
-                block,
-            );
-            return block;
-        }
-
-        fn writeThread(
-            self: *Self,
-            wrt: anytype,
-            comptime finish: anytype,
-            finish_args: anytype,
-        ) void {
-            var cur_idx: usize = 0;
-            self.completion.mut.lock();
-            defer self.completion.mut.unlock();
-            while (cur_idx < self.numBlocks() and !self.completion.hasErrs()) {
-                self.completion.condWait();
-                if (self.completion.hasErrs()) break;
-                if (comptime std.meta.hasFn(@TypeOf(wrt), "pwrite")) {
-                    for (self.completion.map.keys()) |_| {
-                        const k = self.completion.map.keys()[0];
-                        const blk = self.completion.getBlock(k).?;
-                        defer self.alloc.free(blk);
-                        if (blk.len > 0) {
-                            _ = wrt.pwrite(blk, self.block_size * k) catch |err| {
-                                self.completion.addErr(err);
-                                break;
-                            };
-                        } else {
-                            _ = wrt.pwrite(&[1]u8{0}, (self.block_size * (k + 1)) - 1) catch |err| {
-                                self.completion.addErr(err);
-                                break;
-                            };
-                        }
-                        cur_idx += 1;
-                    }
-                    continue;
-                } else {
-                    while (self.completion.getBlock(cur_idx)) |blk| {
-                        defer self.alloc.free(blk);
-                        if (blk.len > 0) {
-                            _ = wrt.write(blk) catch |err| {
-                                self.completion.addErr(err);
-                                break;
-                            };
-                        } else {
-                            const blank: [1024 * 1024]u8 = [1]u8{0} ** (1024 * 1024);
-                            _ = wrt.write(blank[0..self.block_size]) catch |err| {
-                                self.completion.addErr(err);
-                                break;
-                            };
-                        }
-                        cur_idx += 1;
-                    }
-                }
-            }
-            if (comptime @TypeOf(finish) != @TypeOf(null) and @TypeOf(finish_args) != @TypeOf(null)) @call(.auto, finish, finish_args);
-        }
-        fn decompThread(
-            self: *Self,
-            idx: usize,
-        ) void {
-            if (self.completion.hasErrs()) return;
-            defer self.completion.cond.signal();
-            const block = self.blockAt(idx) catch |err| {
-                self.completion.addErr(err);
-                return;
-            };
-            self.completion.add(idx, block) catch |err| {
-                self.completion.addErr(err);
-            };
-        }
-    };
-}

src/reader/metadata.zig

@@ -1,82 +0,0 @@
-const std = @import("std");
-
-const PRead = @import("p_read.zig").PRead;
-const Compression = @import("../superblock.zig").Compression;
-
-const MetaHeader = packed struct {
-    size: u15,
-    uncompressed: bool,
-};
-
-pub fn MetadataReader(comptime T: type) type {
-    comptime std.debug.assert(std.meta.hasFn(T, "read"));
-    return struct {
-        const Self = @This();
-
-        alloc: std.mem.Allocator,
-        comp: Compression,
-        rdr: PRead(T),
-        offset: u64,
-
-        block: [8192]u8 = undefined,
-        block_size: usize = 0,
-        block_offset: u32 = 0,
-
-        pub fn init(alloc: std.mem.Allocator, comp: Compression, rdr: PRead(T), offset: u64) Self {
-            return .{
-                .alloc = alloc,
-                .comp = comp,
-                .rdr = rdr,
-                .offset = offset,
-            };
-        }
-
-        fn readNextBlock(self: *Self) !void {
-            var hdr: MetaHeader = undefined;
-            _ = try self.rdr.pread(std.mem.asBytes(&hdr), self.offset);
-            self.offset += 2;
-            if (hdr.uncompressed) {
-                self.block_size = try self.rdr.pread(self.block[0..hdr.size], self.offset);
-            } else {
-                self.block_size = try self.comp.decompress(
-                    8192,
-                    self.alloc,
-                    self.rdr.readerAt(self.offset).reader(),
-                    &self.block,
-                );
-            }
-            self.offset += hdr.size;
-            self.block_offset = 0;
-        }
-
-        pub fn skip(self: *Self, offset: u32) !void {
-            var skipped: u32 = 0;
-            var hdr: MetaHeader = undefined;
-            while (offset - skipped >= 8192) {
-                _ = try self.rdr.pread(std.mem.asBytes(&hdr), self.offset);
-                self.offset += 2 + hdr.size;
-                skipped += 8192;
-            }
-            var to_skip: u32 = 0;
-            while (skipped < offset) {
-                if (self.block_offset >= self.block_size) try self.readNextBlock();
-                to_skip = @min(self.block_size - self.block_offset, offset - skipped);
-                self.block_offset += to_skip;
-                skipped += to_skip;
-            }
-        }
-
-        pub fn read(self: *Self, buf: []u8) !usize {
-            var cur_red: usize = 0;
-            var to_read: usize = 0;
-            while (cur_red < buf.len) {
-                if (self.block_offset >= self.block_size) try self.readNextBlock();
-                to_read = @min(buf.len - cur_red, self.block_size - self.block_offset);
-                @memcpy(buf[cur_red .. cur_red + to_read], self.block[self.block_offset .. self.block_offset + to_read]);
-                cur_red += to_read;
-                self.block_offset += @truncate(to_read);
-            }
-            return cur_red;
-        }
-    };
-}

src/reader/p_read.zig

@@ -1,29 +0,0 @@
-const std = @import("std");
-
-const ToRead = @import("to_read.zig").ToRead;
-
-/// A simple wrapper around a type with the pread([]u8, u64) function.
-/// Provides a couple useful utility functions.
-pub fn PRead(comptime T: type) type {
-    comptime std.debug.assert(std.meta.hasFn(T, "pread"));
-    return struct {
-        const Self = @This();
-
-        rdr: T,
-        offset: u64,
-
-        pub fn init(rdr: T, offset: u64) Self {
-            return .{
-                .rdr = rdr,
-                .offset = offset,
-            };
-        }
-
-        pub fn pread(self: Self, buf: []u8, offset: u64) !usize {
-            return self.rdr.pread(buf, self.offset + offset);
-        }
-        pub fn readerAt(self: Self, offset: u64) ToRead(T) {
-            return .init(self.rdr, self.offset + offset);
-        }
-    };
-}

src/reader/to_read.zig

@@ -1,43 +0,0 @@
-const std = @import("std");
-
-pub fn ToRead(comptime T: type) type {
-    comptime std.debug.assert(std.meta.hasFn(T, "pread"));
-    return struct {
-        const Self = @This();
-
-        pub const Error = anyerror;
-
-        rdr: T,
-        offset: u64,
-
-        pub fn init(rdr: T, init_offset: u64) Self {
-            return .{
-                .rdr = rdr,
-                .offset = init_offset,
-            };
-        }
-
-        pub fn read(self: *Self, buf: []u8) !usize {
-            const red = try self.rdr.pread(buf, self.offset);
-            self.offset += red;
-            return red;
-        }
-        pub fn readAll(self: *Self, buf: []u8) !usize {
-            var cur_red = try self.read(buf);
-            if (cur_red == 0) return cur_red;
-            var res: usize = 0;
-            while (cur_red < buf.len) {
-                res = try self.read(buf[cur_red..]);
-                if (res == 0) break;
-                cur_red += res;
-            }
-            return cur_red;
-        }
-        const Reader = std.io.GenericReader(*Self, anyerror, read);
-        pub fn reader(self: anytype) Reader {
-            return .{
-                .context = @constCast(self),
-            };
-        }
-    };
-}

src/root.zig

@@ -1,62 +1,2 @@
-const std = @import("std");
-
-pub const SfsReader = @import("reader.zig").SfsReader;
-pub const ExtractionOptions = @import("extract_options.zig");
-
-pub const SfsFile = SfsReader(std.fs.File);
-
-const test_archive = "testing/LinuxPATest.sfs";
-
-test "OpenFile" {
-    const sfs_fil = try std.fs.cwd().openFile(test_archive, .{});
-    defer sfs_fil.close();
-    var rdr: SfsFile = try .init(std.testing.allocator, sfs_fil, 0);
-    defer rdr.deinit();
-    _ = try rdr.frag_table.get(rdr.super.frag_count - 1);
-    _ = try rdr.id_table.get(rdr.super.id_count - 1);
-    _ = try rdr.export_table.get(rdr.super.inode_count - 1);
-    std.debug.print("{}\n", .{rdr.super});
-    var root = try rdr.root();
-    defer root.deinit();
-    var iter = root.iterate();
-    while (true) {
-        var f = try iter.next();
-        if (f == null) break;
-        defer f.?.deinit();
-        std.debug.print("{s}\n", .{f.?.name});
-    }
-    std.debug.print("Finished OpenFile test\n", .{});
-}
-
-test "ExtractSingleFile" {
-    const single_file = "PortableApps/Notepad++Portable/App/Notepad++/doLocalConf.xml";
-    const single_file_extr_loc = "testing/doLocalConf.xml";
-
-    std.fs.cwd().deleteFile(single_file_extr_loc) catch {};
-    const sfs_fil = try std.fs.cwd().openFile(test_archive, .{});
-    defer sfs_fil.close();
-    var rdr: SfsFile = try .init(std.testing.allocator, sfs_fil, 0);
-    defer rdr.deinit();
-    var fil = try rdr.open(single_file);
-    defer fil.deinit();
-    var op: ExtractionOptions = try .init();
-    op.verbose = true;
-    try fil.extract(op, single_file_extr_loc);
-
-    std.debug.print("Finished ExtractSingleFile test\n", .{});
-}
-
-test "ExtractAll" {
-    const extr_dir = "testing/testExtract";
-
-    std.fs.cwd().deleteTree(extr_dir) catch {};
-    const sfs_fil = try std.fs.cwd().openFile(test_archive, .{});
-    defer sfs_fil.close();
-    var rdr: SfsFile = try .init(std.testing.allocator, sfs_fil, 0);
-    defer rdr.deinit();
-    const op: ExtractionOptions = try .init();
-    // op.verbose = true;
-    try rdr.extract(op, extr_dir);
-
-    std.debug.print("Finished ExtractAll test\n", .{});
-}
+pub const Archive = @import("archive.zig");
+pub const ExtractionOptions = @import("options.zig");

src/superblock.zig

@@ -1,79 +0,0 @@
-const std = @import("std");
-
-const InodeRef = @import("inode.zig").Ref;
-
-pub const Superblock = packed struct {
-    magic: u32,
-    inode_count: u32,
-    mod_time: u32,
-    block_size: u32,
-    frag_count: u32,
-    comp: Compression,
-    block_log: u16,
-    flags: packed struct {
-        _: u4,
-        id_uncomp: bool,
-        comp_options: bool,
-        no_xattr: bool,
-        xattr_uncomp: bool,
-        has_export: bool,
-        de_dupe: bool,
-        frag_always: bool,
-        no_frag: bool,
-        frag_uncomp: bool,
-        check: bool,
-        data_uncomp: bool,
-        inode_uncomp: bool,
-    },
-    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,
-};
-
-pub const DecompressError = error{
-    LzoUnavailable,
-    Lz4Unavailable,
-};
-
-pub const Compression = enum(u16) {
-    gzip = 1,
-    lzma,
-    lzo,
-    xz,
-    lz4,
-    zstd,
-
-    pub fn decompress(self: Compression, comptime max_size: u32, alloc: std.mem.Allocator, source: anytype, dest: []u8) !usize {
-        switch (self) {
-            .gzip => {
-                var decomp = std.compress.zlib.decompressor(source);
-                return decomp.read(dest);
-            },
-            .lzma => {
-                var decomp = try std.compress.lzma.decompress(alloc, source);
-                defer decomp.deinit();
-                return decomp.read(dest);
-            },
-            .lzo => return DecompressError.LzoUnavailable,
-            .xz => {
-                var decomp = try std.compress.xz.decompress(alloc, source);
-                defer decomp.deinit();
-                return decomp.read(dest);
-            },
-            .lz4 => return DecompressError.Lz4Unavailable,
-            .zstd => {
-                var window: [max_size]u8 = undefined;
-                var decomp = std.compress.zstd.decompressor(source, .{ .window_buffer = &window });
-                return decomp.read(dest);
-            },
-        }
-    }
-};

src/table.zig

@@ -1,75 +0,0 @@
-const std = @import("std");
-
-const PRead = @import("reader/p_read.zig").PRead;
-const Compression = @import("superblock.zig").Compression;
-const MetadataReader = @import("reader/metadata.zig").MetadataReader;
-
-pub const TableError = error{
-    InvalidIndex,
-};
-
-pub fn Table(comptime T: type, comptime R: type) type {
-    comptime std.debug.assert(std.meta.hasFn(R, "pread"));
-    return struct {
-        const Self = @This();
-
-        alloc: std.mem.Allocator,
-        rdr: PRead(R),
-        comp: Compression,
-
-        offset: u64,
-        table_count: u32,
-        mut: std.Thread.RwLock = .{},
-
-        table: []T = &[0]T{},
-
-        pub fn init(alloc: std.mem.Allocator, rdr: PRead(R), comp: Compression, offset: u64, table_count: u32) Self {
-            return .{
-                .alloc = alloc,
-                .rdr = rdr,
-                .comp = comp,
-                .offset = offset,
-                .table_count = table_count,
-            };
-        }
-        pub fn deinit(self: Self) void {
-            self.alloc.free(self.table);
-        }
-
-        fn resize(self: *Self, to_add: usize) !void {
-            if (!self.alloc.resize(self.table, self.table.len + to_add)) {
-                const new_table = try self.alloc.alloc(T, self.table.len + to_add);
-                @memcpy(new_table[0..self.table.len], self.table);
-                self.alloc.free(self.table);
-                self.table = new_table;
-            }
-        }
-
-        pub fn get(self: *Self, idx: u32) !T {
-            if (idx >= self.table_count) return TableError.InvalidIndex;
-            self.mut.lockShared();
-            defer self.mut.unlockShared();
-            if (idx >= self.table.len) {
-                return self.getAndFill(idx);
-            }
-            return self.table[idx];
-        }
-        fn getAndFill(self: *Self, idx: u32) !T {
-            self.mut.unlockShared();
-            defer self.mut.lockShared();
-            self.mut.lock();
-            defer self.mut.unlock();
-            var to_read: usize = 0;
-            var offset: u64 = 0;
-            while (idx >= self.table.len) {
-                to_read = @min(self.table_count - self.table.len, comptime 8192 / @sizeOf(T));
-                try self.resize(to_read);
-                _ = try self.rdr.pread(std.mem.asBytes(&offset), self.offset);
-                self.offset += 8;
-                var meta: MetadataReader(R) = .init(self.alloc, self.comp, self.rdr, offset);
-                _ = try meta.read(std.mem.sliceAsBytes(self.table[self.table.len - to_read ..]));
-            }
-            return self.table[idx];
-        }
-    };
-}

src/test.zig

@@ -0,0 +1,89 @@
+const std = @import("std");
+const Io = std.Io;
+const io = std.testing.io;
+const alloc = std.testing.allocator;
+const stuff = @import("builtin");
+
+const Archive = @import("archive.zig");
+const Superblock = Archive.Superblock;
+
+const TestArchive = "testing/LinuxPATest.sfs";
+
+test "Basics" {
+    std.debug.print("Starting test: Basics...\n", .{});
+
+    var fil = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer fil.close(io);
+    var sfs: Archive = try .init(io, fil, 0);
+    try std.testing.expectEqualDeep(sfs.super, LinuxPATestCorrectSuperblock);
+    const root_file = try sfs.root(alloc, io);
+    defer root_file.deinit();
+}
+
+const TestFile = "Start.exe";
+const TestFileExtractLocation = "testing/Start.exe";
+
+test "ExtractSingleFile" {
+    std.debug.print("Starting test: ExtractSingleFile...\n", .{});
+
+    Io.Dir.cwd().deleteFile(io, TestFileExtractLocation) catch {};
+    var fil = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer fil.close(io);
+    var sfs: Archive = try .init(io, fil, 0);
+    var test_fil = try sfs.open(alloc, io, TestFile);
+    defer test_fil.deinit();
+    try test_fil.extract(alloc, io, TestFileExtractLocation, try .Default());
+    //TODO: validate extracted file.
+}
+
+const TestFullExtractLocation = "testing/TestExtract";
+
+test "ExtractCompleteArchive" {
+    std.debug.print("Starting test: ExtractCompleteArchive...\n", .{});
+
+    Io.Dir.cwd().deleteTree(io, TestFullExtractLocation) catch {};
+    var fil = try Io.Dir.cwd().openFile(io, TestArchive, .{});
+    defer fil.close(io);
+    var sfs: Archive = try .init(io, fil, 0);
+    try sfs.extract(alloc, io, TestFullExtractLocation, try .Default());
+}
+
+const LinuxPATestCorrectSuperblock: Superblock = .{
+    .magic = std.mem.readInt(u32, "hsqs", .little),
+    .inode_count = 2974,
+    .mod_time = 1632696724,
+    .block_size = 131072,
+    .frag_count = 264,
+    .compression = .zstd,
+    .block_log = 17,
+    .flags = .{
+        .inode_uncompressed = false,
+        .data_uncompressed = false,
+        .check = false,
+        .frag_uncompressed = false,
+        .fragment_never = false,
+        .fragment_always = false,
+        .duplicates = true,
+        .exportable = true,
+        .xattr_uncompressed = false,
+        .xattr_never = false,
+        .compression_options = false,
+        .ids_uncompressed = false,
+        ._ = 0,
+    },
+    .id_count = 1,
+    .ver_maj = 4,
+    .ver_min = 0,
+    .root_ref = .{
+        .block_offset = 1363,
+        .block_start = 29237,
+        ._ = 0,
+    },
+    .size = 106841744,
+    .id_start = 106841632,
+    .xattr_start = 106841720,
+    .inode_start = 106778274,
+    .dir_start = 106807998,
+    .frag_start = 106837747,
+    .export_start = 106841602,
+};

src/util/data_extractor.zig

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

src/util/data_reader.zig

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

src/util/decompressor.zig

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

src/util/metadata.zig

@@ -0,0 +1,103 @@
+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 Decompressor = @import("decompressor.zig");
+
+const BlockHeader = packed struct(u16) {
+    size: u15,
+    uncompressed: bool,
+};
+
+const This = @This();
+
+alloc: std.mem.Allocator,
+rdr: *Reader,
+decomp: *const Decompressor,
+
+cur_block_start: u32 = 0,
+next_start_start: u32 = 0,
+buf: [8192]u8 = undefined,
+
+err: ?anyerror = null,
+interface: Reader = .{
+    .buffer = &[0]u8{},
+    .end = 0,
+    .seek = 0,
+    .vtable = &.{
+        .stream = stream,
+        .discard = discard,
+        .readVec = readVec,
+        // TODO: Potentially add rebase so that we can guarentee that self.block_start & interface.seek is correct.
+    },
+},
+
+pub fn init(alloc: std.mem.Allocator, rdr: *Reader, decomp: *const Decompressor) This {
+    return .{
+        .alloc = alloc,
+        .rdr = rdr,
+        .decomp = decomp,
+    };
+}
+
+fn advance(self: *This) !void {
+    self.interface.seek = 0;
+    var hdr: BlockHeader = undefined;
+    try self.rdr.readSliceEndian(BlockHeader, @ptrCast(&hdr), .little);
+    self.cur_block_start = self.next_start_start;
+    self.next_start_start += hdr.size;
+    if (hdr.uncompressed) {
+        try self.rdr.readSliceEndian(u8, self.buf[0..hdr.size], .little);
+        self.interface.end = hdr.size;
+        self.interface.buffer = self.buf[0..hdr.size];
+        return;
+    } else {
+        @branchHint(.likely);
+        var tmp_buf: [8192]u8 = undefined;
+        try self.rdr.readSliceAll(tmp_buf[0..hdr.size]);
+        self.interface.end = try self.decomp.Decompress(self.alloc, tmp_buf[0..hdr.size], &self.buf);
+        self.interface.buffer = self.buf[0..self.interface.end];
+    }
+}
+
+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) Reader.Error!usize {
+    const self: *This = @fieldParentPtr("interface", rdr);
+    if (rdr.end == rdr.seek) self.advance() catch |err| {
+        self.err = err;
+        return error.ReadFailed;
+    };
+    if (@intFromEnum(limit) == 0) return 0;
+    const to_skip = @min(rdr.end - rdr.seek, @intFromEnum(limit));
+    rdr.seek += to_skip;
+    return to_skip;
+}
+fn readVec(rdr: *Reader, vec: [][]u8) Reader.Error!usize {
+    const self: *This = @fieldParentPtr("interface", rdr);
+    if (rdr.end == rdr.seek) self.advance() catch |err| {
+        self.err = err;
+        return 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], 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/misc.zig

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

src/util/offset_file.zig

@@ -0,0 +1,24 @@
+//! A File where it's meaningful (to us) content starts at a given offset.
+
+const std = @import("std");
+const Io = std.Io;
+const File = Io.File;
+const Reader = 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, io: Io, offset: u64, buffer: []u8) Reader.SeekError!Reader {
+    var rdr = self.fil.reader(io, buffer);
+    try rdr.seekTo(self.offset + offset);
+    return rdr;
+}
+pub fn readAt(self: OffsetFile, io: Io, offset: u64, buf: []u8) File.ReadPositionalError!void {
+    _ = try self.fil.readPositionalAll(io, buf, self.offset + offset);
+}

src/util/shared_cache.zig

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

src/xattr_table.zig

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