(Mostly) Finished extraction (currently infinitely hanging)

Added DataExtract
Added LookupTable

.zed/settings.json

@@ -9,14 +9,9 @@
 				"usePlaceholders": false,
 			},
 			"settings": {
-				// "build_on_save": true,
+				"build_on_save": true,
 				"use_placeholders": false,
-				"build_on_save_args": [
-					"-fincremental",
-					"-Dallow_lzo=true",
-					"-Ddebug=true",
-					"test",
-				],
+				"build_on_save_args": ["-fincremental", "-Dallow_lzo=true"],
 			},
 		},
 	},

mise.toml

@@ -1,2 +1,2 @@
 [tools]
-zig = "master"
+zig = "0.16.0"

src/archive.zig

@@ -7,6 +7,7 @@ const config = @import("config");
 
 const ExtractionOptions = @import("options.zig");
 const File = @import("file.zig");
+const Inode = @import("inode.zig");
 const Superblock = @import("super.zig").Superblock;
 const DecompCache = @import("util/decomp_cache.zig");
 const CompressionType = @import("util/decompress.zig").CompressionType;
@@ -16,7 +17,6 @@ const Archive = @This();
 const CACHE_MIN = 16 * 1024 * 1024;
 const CACHE_MAX = 1 * 1024 * 1024 * 1024;
 
-map: MemoryMap,
 cache: DecompCache,
 
 super: Superblock,
@@ -37,14 +37,6 @@ pub fn initAdvanced(alloc: std.mem.Allocator, io: Io, file: Io.File, offset: u64
     if (!config.use_zig_decomp and config.allow_lzo)
         _ = c.lzo_init();
 
-    const map = try file.createMemoryMap(
-        io,
-        .{
-            .offset = offset,
-            .len = super.size,
-            .protection = .{ .read = true },
-        },
-    );
     const cache_size = blk: {
         if (max_cache_size > CACHE_MIN) break :blk CACHE_MIN;
         const sys_mem = std.process.totalSystemMemory() catch break :blk CACHE_MIN;
@@ -54,10 +46,16 @@ pub fn initAdvanced(alloc: std.mem.Allocator, io: Io, file: Io.File, offset: u64
         break :blk min;
     };
     return .{
-        .map = map,
         .cache = try .init(
             alloc,
-            map,
+            try file.createMemoryMap(
+                io,
+                .{
+                    .offset = offset,
+                    .len = super.size,
+                    .protection = .{ .read = true },
+                },
+            ),
             super.compression,
             cache_size,
         ),
@@ -67,7 +65,6 @@ pub fn initAdvanced(alloc: std.mem.Allocator, io: Io, file: Io.File, offset: u64
 }
 pub fn deinit(self: *Archive, io: Io) void {
     self.cache.deinit(io);
-    self.map.destroy(io);
 }
 
 pub fn root(self: *Archive, alloc: std.mem.Allocator, io: Io) !File {
@@ -86,10 +83,18 @@ pub fn open(self: *Archive, alloc: std.mem.Allocator, io: Io, filepath: []const
 }
 
 pub fn extract(self: *Archive, alloc: std.mem.Allocator, io: Io, ext_dir: []const u8, options: ExtractionOptions) !void {
-    _ = self;
-    _ = alloc;
-    _ = io;
-    _ = ext_dir;
-    _ = options;
-    return error.TODO;
+    const root_inode: Inode = try .fromRef(alloc, io, &self.cache, self.super.inode_start, self.super.block_size, self.super.root_ref);
+    return root_inode.extract(
+        alloc,
+        io,
+        &self.cache,
+        self.super.dir_start,
+        self.super.inode_start,
+        self.super.frag_start,
+        self.super.block_size,
+        self.super.id_start,
+        self.super.xattr_start,
+        ext_dir,
+        options,
+    );
 }

src/dir_entry.zig

@@ -15,6 +15,8 @@ const Entry = extern struct {
     name_size: u16,
 };
 
+pub const Error = error{OutOfMemory} || std.Io.Reader.Error;
+
 const DirEntry = @This();
 
 inode_type: Inode.Type,
@@ -28,7 +30,7 @@ pub fn deinit(self: DirEntry, alloc: std.mem.Allocator) void {
     alloc.free(self.name);
 }
 
-pub fn readEntries(alloc: std.mem.Allocator, rdr: *Reader, size: u32) ![]DirEntry {
+pub fn readEntries(alloc: std.mem.Allocator, rdr: *Reader, size: u32) Error![]DirEntry {
     var out: std.ArrayList(DirEntry) = try .initCapacity(alloc, 50);
     errdefer out.deinit(alloc);
 

src/file.zig

@@ -7,6 +7,7 @@ const Archive = @import("archive.zig");
 const DirEntry = @import("dir_entry.zig");
 const ExtractionOptions = @import("options.zig");
 const Inode = @import("inode.zig");
+const LookupTable = @import("lookup_table.zig");
 const MetadataReader = @import("util/metadata.zig");
 
 pub const Error = error{
@@ -108,11 +109,18 @@ pub fn open(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8)
     return fil.open(alloc, io, filepath[first_element.len..]);
 }
 
-pub fn extract(self: File, alloc: std.mem.Allocator, io: Io, ext_loc: []const u8, options: ExtractionOptions) !void {
-    _ = self;
-    _ = alloc;
-    _ = io;
-    _ = ext_loc;
-    _ = options;
-    return error.TODO;
+pub fn extract(self: File, alloc: std.mem.Allocator, io: Io, path: []const u8, options: ExtractionOptions) !void {
+    return self.inode.extract(
+        alloc,
+        io,
+        &self.archive.cache,
+        self.archive.super.dir_start,
+        self.archive.super.inode_start,
+        self.archive.super.frag_start,
+        self.archive.super.block_size,
+        self.archive.super.id_start,
+        self.archive.super.xattr_start,
+        path,
+        options,
+    );
 }

src/frag.zig

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

src/inode.zig

@@ -5,9 +5,13 @@ const Io = std.Io;
 const Reader = Io.Reader;
 
 const DirEntry = @import("dir_entry.zig");
+const ExtractionOptions = @import("options.zig");
+const FragEntry = @import("frag.zig").FragEntry;
 const DirTypes = @import("inode_data/dir.zig");
 const FileTypes = @import("inode_data/file.zig");
 const MiscTypes = @import("inode_data/misc.zig");
+const LookupTable = @import("lookup_table.zig");
+const DataExtract = @import("util/data_extract.zig");
 const DecompCache = @import("util/decomp_cache.zig");
 const MetadataReader = @import("util/metadata.zig");
 
@@ -147,3 +151,255 @@ fn readDirectoryFromData(alloc: std.mem.Allocator, io: Io, cache: *DecompCache,
 
     return DirEntry.readEntries(alloc, &meta.interface, d.size);
 }
+
+// Extraction
+
+pub const ExtractionError = error{ SetXattr, Mknod, Canceled } || DirEntry.Error || Io.Dir.CreateFileAtomicError || DataExtract.Error || Io.File.Atomic.LinkError ||
+    Io.Dir.SymLinkError;
+
+const ExtractReturn = struct {
+    path: []const u8,
+    inode: Inode,
+
+    fn deinit(self: ExtractReturn, alloc: std.mem.Allocator) void {
+        self.inode.deinit(alloc);
+        alloc.free(self.path);
+    }
+    fn setMetadata(self: ExtractReturn, alloc: std.mem.Allocator, io: Io, cache: *DecompCache, id_start: u64, xattr_start: u64, options: ExtractionOptions) !void {
+        defer self.deinit(alloc);
+        if (options.ignore_permissions and options.ignore_xattr) return;
+
+        var fil = try Io.Dir.cwd().openFile(io, self.path, .{});
+        defer fil.close(io);
+
+        if (!options.ignore_permissions) {
+            try fil.setTimestamps(io, .{ .modify_timestamp = .{
+                .new = .{ .nanoseconds = self.inode.hdr.mod_time * std.time.ns_per_s },
+            } });
+            try fil.setPermissions(io, @enumFromInt(self.inode.hdr.permissions));
+            try fil.setOwner(
+                io,
+                try LookupTable.lookup(u16, io, cache, id_start, self.inode.hdr.uid_idx),
+                try LookupTable.lookup(u16, io, cache, id_start, self.inode.hdr.gid_idx),
+            );
+        }
+        if (options.ignore_xattr or @hasField(std.os, "linux")) return;
+        const xattr_idx: u32 = switch (self.inode.data) {
+            .ext_dir => |d| d.xattr_idx,
+            .ext_file => |f| f.xattr_idx,
+            .ext_symlink => |s| s.xattr_idx,
+            .ext_block_dev, .ext_char_dev => |d| d.xattr_idx,
+            .ext_fifo, .ext_socket => |i| i.xattr_idx,
+            else => return,
+        };
+        if (xattr_idx == 0xFFFFFFFF) return;
+        const xattrs = try LookupTable.xattrLookup(alloc, io, cache, xattr_start, xattr_idx);
+        defer {
+            for (xattrs) |kv|
+                kv.deinit(alloc);
+            alloc.free(xattrs);
+        }
+
+        for (xattrs) |kv| {
+            const res = std.os.linux.fsetxattr(fil.handle, kv.key.ptr, kv.value.ptr, kv.value.len, 0);
+            if (res != 0)
+                return ExtractionError.SetXattr;
+        }
+    }
+};
+const ExtractUnion = union { ret: ExtractionError!ExtractReturn };
+
+pub fn extract(
+    self: Inode,
+    alloc: std.mem.Allocator,
+    io: Io,
+    cache: *DecompCache,
+    dir_start: u64,
+    inode_start: u64,
+    frag_start: u64,
+    block_size: u32,
+    id_start: u64,
+    xattr_start: u64,
+    ext_loc: []const u8,
+    options: ExtractionOptions,
+) !void {
+    const path = std.mem.trimEnd(u8, ext_loc, "/");
+
+    var sel_buf: [5]ExtractUnion = undefined;
+    var sel: Io.Select(ExtractUnion) = .init(io, &sel_buf);
+    defer sel.cancelDiscard();
+
+    var meta_loop = io.async(metadataLoop, .{ alloc, io, cache, id_start, xattr_start, &sel, options });
+
+    sel.async(.ret, extractReal, .{ self, alloc, io, cache, dir_start, inode_start, frag_start, block_size, &sel, path, true });
+
+    try meta_loop.await(io);
+}
+fn extractReal(
+    self: Inode,
+    alloc: std.mem.Allocator,
+    io: Io,
+    cache: *DecompCache,
+    dir_start: u64,
+    inode_start: u64,
+    frag_start: u64,
+    block_size: u32,
+    master_sel: *Io.Select(ExtractUnion),
+    path: []const u8,
+    origin: bool,
+) ExtractionError!ExtractReturn {
+    errdefer if (!origin) {
+        self.deinit(alloc);
+        alloc.free(path);
+    };
+    switch (self.hdr.inode_type) {
+        .dir, .ext_dir => {
+            const entries = self.readDirectory(alloc, io, cache, dir_start) catch |err| switch (err) {
+                error.NotDirectory => unreachable,
+                else => |e| return e,
+            };
+            defer {
+                for (entries) |entry|
+                    entry.deinit(alloc);
+                alloc.free(entries);
+            }
+
+            var sel_buf: [5]ExtractUnion = undefined;
+            var sel: Io.Select(ExtractUnion) = .init(io, &sel_buf);
+            defer sel.cancelDiscard();
+
+            var dir_loop = io.async(dirLoop, .{ alloc, io, &sel, master_sel });
+
+            for (entries) |entry| {
+                var meta: MetadataReader = .init(io, cache, inode_start + entry.block_start);
+                defer meta.deinit();
+                try meta.interface.discardAll(entry.block_offset);
+
+                var new_inode: Inode = try .fromReader(alloc, &meta.interface, block_size);
+                errdefer new_inode.deinit(alloc);
+
+                const new_path = try std.mem.concat(alloc, u8, &.{ path, "/", entry.name });
+                errdefer alloc.free(new_path);
+
+                sel.async(.ret, extractReal, .{ new_inode, alloc, io, cache, dir_start, inode_start, frag_start, block_size, master_sel, new_path, false });
+            }
+
+            try dir_loop.await(io);
+        },
+        .file, .ext_file => {
+            var atomic = try Io.Dir.cwd().createFileAtomic(io, path, .{});
+            defer atomic.deinit(io);
+
+            var data: DataExtract = undefined;
+            var frag_offset: ?u64 = null;
+            switch (self.data) {
+                .file => |f| {
+                    data = .init(cache.decomp, cache.map, block_size, f.block_start, f.size, f.block_sizes);
+                    if (f.frag_idx != 0xFFFFFFFF) {
+                        const entry: FragEntry = try LookupTable.lookup(FragEntry, io, cache, frag_start, f.frag_idx);
+                        if (entry.size.uncompressed) {
+                            data.addFrag(cache.map.memory[entry.start..][0..entry.size.size], f.frag_offset);
+                        } else {
+                            frag_offset = entry.start;
+                            const block = try cache.checkoutBlock(io, entry.start, entry.size.size, block_size);
+                            data.addFrag(block, f.frag_offset);
+                        }
+                    }
+                },
+                .ext_file => |f| {
+                    data = .init(cache.decomp, cache.map, block_size, f.block_start, f.size, f.block_sizes);
+                    if (f.frag_idx != 0xFFFFFFFF) {
+                        const entry: FragEntry = try LookupTable.lookup(FragEntry, io, cache, frag_start, f.frag_idx);
+                        if (entry.size.uncompressed) {
+                            data.addFrag(cache.map.memory[entry.start..][0..entry.size.size], f.frag_offset);
+                        } else {
+                            frag_offset = entry.start;
+                            const block = try cache.checkoutBlock(io, entry.start, entry.size.size, block_size);
+                            data.addFrag(block, f.frag_offset);
+                        }
+                    }
+                },
+                else => unreachable,
+            }
+            defer if (frag_offset != null) cache.checkinBlock(io, frag_offset.?);
+
+            try data.asyncExtract(alloc, io, atomic.file);
+
+            try atomic.link(io);
+        },
+        .symlink, .ext_symlink => {
+            const target = switch (self.data) {
+                .symlink => |s| s.target,
+                .ext_symlink => |s| s.target,
+                else => unreachable,
+            };
+            try Io.Dir.cwd().symLink(io, target, path, .{});
+        },
+        else => {
+            var dev: u32 = 0;
+            var mode: u32 = undefined;
+
+            const DT = std.os.linux.DT;
+
+            switch (self.data) {
+                .block_dev => |d| {
+                    mode = DT.BLK;
+                    dev = d.dev;
+                },
+                .ext_block_dev => |d| {
+                    mode = DT.BLK;
+                    dev = d.dev;
+                },
+                .char_dev => |d| {
+                    mode = DT.CHR;
+                    dev = d.dev;
+                },
+                .ext_char_dev => |d| {
+                    mode = DT.CHR;
+                    dev = d.dev;
+                },
+                .fifo, .ext_fifo => mode = DT.FIFO,
+                .socket, .ext_socket => mode = DT.SOCK,
+                else => unreachable,
+            }
+
+            const sentinel_path = try std.mem.concatWithSentinel(alloc, u8, &.{path}, 0);
+            defer alloc.free(sentinel_path);
+            const res = std.os.linux.mknod(sentinel_path, mode, dev);
+            if (res != 0)
+                return ExtractionError.Mknod;
+        },
+    }
+
+    return .{
+        .path = path,
+        .inode = self,
+    };
+}
+fn metadataLoop(alloc: std.mem.Allocator, io: Io, cache: *DecompCache, id_start: u64, xattr_start: u64, sel: *Io.Select(ExtractUnion), options: ExtractionOptions) !void {
+    defer {
+        while (sel.cancel()) |ret| {
+            const res = ret.ret catch continue;
+            res.deinit(alloc);
+        }
+    }
+    while (sel.group.token.load(.unordered) != null) {
+        const ret = try sel.await();
+
+        const res = try ret.ret;
+
+        try res.setMetadata(alloc, io, cache, id_start, xattr_start, options);
+    }
+}
+fn dirLoop(alloc: std.mem.Allocator, io: Io, dir_sel: *Io.Select(ExtractUnion), master_sel: *Io.Select(ExtractUnion)) ExtractionError!void {
+    while (dir_sel.group.token.load(.unordered) != null) {
+        const ret = try dir_sel.await();
+        master_sel.queue.putOne(io, ret) catch |err| switch (err) {
+            error.Closed => {
+                const res = try ret.ret;
+                res.deinit(alloc);
+            },
+            else => |e| return e,
+        };
+    }
+}

src/inode_data/dir.zig

@@ -21,7 +21,7 @@ pub const ExtDir = extern struct {
     parent_num: u32,
     idx_count: u16,
     block_offset: u16,
-    xattr_id: u32,
+    xattr_idx: u32,
     // index: []DirIndex
 
     pub fn read(rdr: *Reader) !ExtDir {

src/inode_data/file.zig

@@ -1,7 +1,7 @@
 const std = @import("std");
 const Reader = std.Io.Reader;
 
-pub const BlockSize = packed struct {
+pub const BlockSize = packed struct(u32) {
     size: u24,
     uncompressed: bool,
     _: u7,

src/lookup_table.zig

@@ -0,0 +1,117 @@
+const std = @import("std");
+const Io = std.Io;
+
+const Inode = @import("inode.zig");
+const DecompCache = @import("util/decomp_cache.zig");
+const MetadataReader = @import("util/metadata.zig");
+
+pub fn lookup(comptime T: anytype, io: Io, cache: *DecompCache, table_start: u64, idx: u32) !T {
+    const PER_BLOCK = 8192 / @sizeOf(T);
+
+    const block_idx = idx / PER_BLOCK;
+    const block_offset = idx % PER_BLOCK;
+
+    const offset: u64 = std.mem.readInt(u64, cache.map.memory[table_start + (block_idx * 8) ..][0..8], .little);
+
+    var meta: MetadataReader = .init(io, cache, offset);
+    defer meta.deinit();
+    try meta.interface.discardAll(block_offset * @sizeOf(T));
+
+    var new: T = undefined;
+    try meta.interface.readSliceEndian(T, @ptrCast(&new), .little);
+    return new;
+}
+
+pub const XattrKV = struct {
+    key: [:0]u8,
+    value: []u8,
+
+    pub fn deinit(self: XattrKV, alloc: std.mem.Allocator) void {
+        alloc.free(self.key);
+        alloc.free(self.value);
+    }
+};
+
+const LookupValue = extern struct {
+    ref: Inode.Ref,
+    count: u32,
+    size: u32,
+};
+const KeyEntry = extern struct {
+    prefix: packed struct(u16) {
+        prefix: enum(u8) {
+            user,
+            trusted,
+            security,
+        },
+        out_of_line: bool,
+        _: u7,
+    },
+    name_size: u8,
+};
+
+pub fn xattrLookup(alloc: std.mem.Allocator, io: Io, cache: *DecompCache, xattr_start: u64, idx: u32) ![]XattrKV {
+    const table_start = std.mem.readInt(u64, cache.map.memory[xattr_start..][0..8], .little);
+
+    const val: LookupValue = try lookup(
+        LookupValue,
+        io,
+        cache,
+        xattr_start + 16,
+        idx,
+    );
+
+    const out = try alloc.alloc(XattrKV, val.count);
+    errdefer alloc.free(out);
+
+    var meta: MetadataReader = .init(io, cache, table_start + val.ref.block_start);
+    defer meta.deinit();
+    try meta.interface.discardAll(val.ref.block_offset);
+
+    for (out) |*kv| {
+        var key_entry: KeyEntry = undefined;
+        try meta.interface.readSliceEndian(KeyEntry, @ptrCast(&key_entry), .little);
+
+        var key_len = key_entry.name_size;
+        key_len += switch (key_entry.prefix.prefix) {
+            .user => 5,
+            .trusted => 8,
+            .security => 9,
+        };
+
+        kv.key = try alloc.allocSentinel(u8, key_len, 0);
+        errdefer alloc.free(kv.key);
+
+        try meta.interface.readSliceEndian(u8, kv.key, .little);
+
+        if (key_entry.prefix.out_of_line) {
+            try meta.interface.discardAll(8);
+
+            var ool_ref: Inode.Ref = undefined;
+            try meta.interface.readSliceEndian(Inode.Ref, @ptrCast(&ool_ref), .little);
+
+            var ool_meta: MetadataReader = .init(io, cache, table_start + ool_ref.block_start);
+            defer ool_meta.deinit();
+            try ool_meta.interface.discardAll(ool_ref.block_offset);
+
+            kv.value = try readValue(alloc, &ool_meta.interface);
+            errdefer alloc.free(kv.value);
+        } else {
+            kv.value = try readValue(alloc, &meta.interface);
+        }
+    }
+
+    return out;
+}
+
+fn readValue(alloc: std.mem.Allocator, rdr: *Io.Reader) ![]u8 {
+    var val_size: u32 = undefined;
+    try rdr.readSliceEndian(u32, @ptrCast(&val_size), .little);
+
+    const val = try alloc.alloc(u8, val_size);
+    errdefer alloc.free(val);
+
+    try rdr.readSliceEndian(u8, val, .little);
+
+    return val;
+}

src/util/c_decomp.zig

@@ -2,7 +2,7 @@ const std = @import("std");
 
 const c = @import("c");
 
-const Error = @import("decompress.zig").DecompressionError;
+const Error = @import("decompress.zig").Error;
 
 pub fn zlibDecompress(_: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
     var strem: c.zng_stream = .{

src/util/data_extract.zig

@@ -0,0 +1,84 @@
+const std = @import("std");
+const Io = std.Io;
+
+const BlockSize = @import("../inode_data/file.zig").BlockSize;
+const Decompress = @import("decompress.zig");
+
+const DataExtract = @This();
+
+decomp: Decompress.Fn,
+map: Io.File.MemoryMap,
+
+block_size: u32,
+block_start: u64,
+size: u64,
+blocks: []BlockSize,
+
+frag_data: ?[]u8 = null,
+frag_offset: u32 = undefined,
+
+pub fn init(decomp: Decompress.Fn, map: Io.File.MemoryMap, block_size: u32, block_start: u64, size: u64, blocks: []BlockSize) DataExtract {
+    return .{
+        .decomp = decomp,
+        .map = map,
+
+        .block_size = block_size,
+        .block_start = block_start,
+        .size = size,
+        .blocks = blocks,
+    };
+}
+pub fn addFrag(self: *DataExtract, frag_block: []u8, frag_offset: u32) void {
+    self.frag_data = frag_block;
+    self.frag_offset = frag_offset;
+}
+
+pub const Error = error{} || Io.File.MemoryMap.CreateError || Io.File.WritePositionalError || Decompress.Error;
+
+pub fn asyncExtract(self: DataExtract, alloc: std.mem.Allocator, io: Io, fil: Io.File) Error!void {
+    var err: ?Error = null;
+
+    var map = try fil.createMemoryMap(io, .{ .len = self.size, .protection = .{ .write = true }, .undefined_contents = true });
+    defer map.destroy(io);
+
+    var group: Io.Group = .init;
+    defer group.cancel(io);
+
+    var offset: u64 = self.block_start;
+    for (0..self.blocks.len) |i| {
+        group.async(io, blockThread, .{ self, alloc, map, offset, i, &err });
+        offset += self.blocks[i].size;
+    }
+    if (self.frag_data != null)
+        group.async(io, fragThread, .{ self, map });
+
+    try group.await(io);
+    if (err != null) return err.?;
+    return map.write(io);
+}
+fn blockThread(self: DataExtract, alloc: std.mem.Allocator, map: Io.File.MemoryMap, read_offset: u64, idx: usize, ret_err: *?Error) error{Canceled}!void {
+    const block = self.blocks[idx];
+    const write_offset = idx * self.block_size;
+
+    const size = if (self.frag_data == null and idx == self.blocks.len - 1)
+        self.size % self.block_size
+    else
+        self.block_size;
+
+    if (block.size == 0) {
+        @memset(map.memory[write_offset..][0..size], 0);
+        return;
+    } else if (block.uncompressed) {
+        @memcpy(self.map.memory[read_offset..][0..size], map.memory[write_offset..][0..size]);
+    }
+    var tmp: [1024 * 1024]u8 = undefined;
+    _ = self.decomp(alloc, self.map.memory[read_offset..][0..block.size], tmp[0..size]) catch |err| {
+        ret_err.* = err;
+        return error.Canceled;
+    };
+    @memcpy(map.memory[write_offset..][0..size], tmp[0..size]);
+}
+fn fragThread(self: DataExtract, map: Io.File.MemoryMap) error{Canceled}!void {
+    const size = self.size % self.block_size;
+    @memcpy(map.memory[self.blocks.len * self.block_size ..][0..size], self.frag_data.?[self.frag_offset..][0..size]);
+}

src/util/decomp_cache.zig

@@ -4,7 +4,7 @@ const ArrayHashMap = std.array_hash_map.Auto;
 const Atomic = std.atomic.Value;
 
 const Decompress = @import("decompress.zig");
-const DecompressFn = Decompress.DecompressFn;
+const Fn = Decompress.Fn;
 const DecompressType = Decompress.CompressionType;
 
 const DecompCache = @This();
@@ -15,7 +15,7 @@ const Cache = struct {
 };
 
 arena: std.heap.ArenaAllocator,
-decomp: DecompressFn,
+decomp: Fn,
 
 map: Io.File.MemoryMap,
 
@@ -42,6 +42,7 @@ pub fn deinit(self: *DecompCache, io: Io) void {
     self.mut.lockUncancelable(io);
     self.cache.deinit(self.arena.child_allocator);
     self.arena.deinit();
+    self.map.destroy(io);
 }
 
 fn makeRoom(self: *DecompCache, io: Io, size: u32) !void {
@@ -68,7 +69,7 @@ pub fn checkinBlock(self: *DecompCache, io: Io, offset: u64) void {
     const res = get.?.usage.fetchSub(1, .acq_rel);
     if (res == 0) self.cond.broadcast(io);
 }
-pub fn checkoutBlock(self: *DecompCache, io: Io, offset: u64, block_size: u32, max_result_size: u32) ![]u8 {
+pub fn checkoutBlock(self: *DecompCache, io: Io, offset: u64, data_size: u32, max_result_size: u32) ![]u8 {
     {
         try self.mut.lockShared(io);
         defer self.mut.unlockShared(io);
@@ -90,7 +91,7 @@ pub fn checkoutBlock(self: *DecompCache, io: Io, offset: u64, block_size: u32, m
     var out = try alloc.alloc(u8, max_result_size);
     errdefer alloc.free(out);
 
-    const out_size = try self.decomp(buf_alloc, self.map.memory[offset..][0..block_size], out);
+    const out_size = try self.decomp(buf_alloc, self.map.memory[offset..][0..data_size], out);
     if (out_size != max_result_size) {
         if (alloc.resize(out, out_size)) {
             out.len = out_size;

src/util/decompress.zig

@@ -6,9 +6,9 @@ const config = @import("config");
 const c_decomp = @import("c_decomp.zig");
 const zig_decomp = @import("zig_decomp.zig");
 
-pub const DecompressionError = Io.Reader.Error || std.mem.Allocator.Error;
+pub const Error = Io.Reader.Error || std.mem.Allocator.Error;
 
-pub const DecompressFn = *const fn (alloc: std.mem.Allocator, in: []u8, out: []u8) DecompressionError!usize;
+pub const Fn = *const fn (alloc: std.mem.Allocator, in: []u8, out: []u8) Error!usize;
 
 pub const CompressionType = enum(u16) {
     gzip = 1,
@@ -19,7 +19,7 @@ pub const CompressionType = enum(u16) {
     zstd,
 };
 
-pub fn getDecompressFn(t: CompressionType) !DecompressFn {
+pub fn getDecompressFn(t: CompressionType) !Fn {
     return if (config.use_zig_decomp) switch (t) {
         .lzo => error.LzoUnsupported,
         .lz4 => error.Lz4Unsupported,

src/util/zig_decomp.zig

@@ -5,7 +5,7 @@ const zstd = std.compress.zstd;
 const xz = std.compress.xz;
 const lzma = std.compress.lzma;
 
-const Error = @import("decompress.zig").DecompressionError;
+const Error = @import("decompress.zig").Error;
 
 pub fn zlibDecompress(_: std.mem.Allocator, in: []u8, out: []u8) Error!usize {
     var buf: [flate.max_window_len]u8 = undefined;