Updated a lot of packed structs to extern struct

Specified int types for remaining packed structs
Instead of manually decoding File & ExtFile structs, decode an extern struct first
Fixed some zstd issues
Some more File stuff

.zed/debug.json

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

src/archive.zig

@@ -48,7 +48,7 @@ pub fn root(self: Archive, alloc: std.mem.Allocator, io: Io) !File {
         self.super.block_size,
         self.super.root_ref,
     );
-    return .init(alloc, root_inode, "");
+    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 {
@@ -61,9 +61,16 @@ pub fn open(self: Archive, alloc: std.mem.Allocator, io: Io, filepath: []const u
 }
 /// 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 {
-    _ = self;
-    _ = alloc;
-    _ = io;
+    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,
+    );
+    _ = root_inode;
     _ = extract_dir;
     _ = options;
     return error.TODO;
@@ -74,7 +81,15 @@ pub fn extract(self: Archive, alloc: std.mem.Allocator, io: Io, extract_dir: []c
 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);
+    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,
@@ -85,6 +100,18 @@ pub fn inode(self: Archive, alloc: std.mem.Allocator, io: Io, num: u32) !Inode {
         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
 
@@ -98,7 +125,7 @@ const SuperblockError = error{
 };
 
 /// A squashfs Superblock
-pub const Superblock = packed struct(u768) {
+pub const Superblock = extern struct {
     magic: u32,
     inode_count: u32,
     mod_time: u32,
@@ -113,7 +140,7 @@ pub const Superblock = packed struct(u768) {
         zstd,
     },
     block_log: u16,
-    flags: packed struct {
+    flags: packed struct(u16) {
         inode_uncompressed: bool,
         data_uncompressed: bool,
         check: bool,

src/decomp/zstd.zig

@@ -57,7 +57,7 @@ fn decomp(d: ?*const Decompressor, alloc: std.mem.Allocator, in: []u8, out: []u8
 
 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(in.len) });
+    var d = zstd.Decompress.init(&rdr, buffer, .{ .window_len = @truncate(out.len) });
 
     return d.reader.readSliceShort(out);
 }
@@ -67,7 +67,7 @@ inline fn zstdDecomp(buffer: []u8, in: []u8, out: []u8) !usize {
 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 + zstd.block_size_max);
+    const buf = try alloc.alloc(u8, out.len + zstd.block_size_max);
     defer alloc.free(buf);
     return zstdDecomp(buf, in, out);
 }

src/directory.zig

@@ -0,0 +1,67 @@
+const std = @import("std");
+const Reader = std.Io.Reader;
+
+const Inode = @import("inode.zig");
+
+const DirEntry = @This();
+
+block_start: u32,
+block_offset: u16,
+type: Inode.Type,
+name: []const u8,
+
+pub fn deinit(self: DirEntry, alloc: std.mem.Allocator) void {
+    alloc.free(self.name);
+}
+
+pub fn readDirectory(alloc: std.mem.Allocator, rdr: *Reader, size: u32) ![]DirEntry {
+    var hdr: Header = undefined;
+    var raw: RawEntry = undefined;
+    var out: std.ArrayList(DirEntry) = try .initCapacity(alloc, 30);
+    errdefer {
+        for (out.items) |ent|
+            alloc.free(ent.name);
+        out.deinit(alloc);
+    }
+
+    var tot_red: u32 = 3;
+    while (tot_red < size) {
+        try rdr.readSliceEndian(Header, @ptrCast(&hdr), .little);
+        try out.ensureUnusedCapacity(alloc, hdr.count + 1);
+
+        tot_red += @sizeOf(Header);
+
+        for (hdr.count + 1) |_| {
+            try rdr.readSliceEndian(RawEntry, @ptrCast(&raw), .little);
+
+            const new_name = try alloc.alloc(u8, raw.name_size + 1);
+            try rdr.readSliceEndian(u8, new_name, .little);
+
+            const new = out.addOneAssumeCapacity();
+            new.* = .{
+                .block_start = hdr.block_start,
+                .block_offset = raw.block_offset,
+                .type = raw.type,
+                .name = new_name,
+            };
+
+            tot_red += @sizeOf(RawEntry) + raw.name_size + 1;
+        }
+    }
+    return out.toOwnedSlice(alloc);
+}
+
+// Types
+
+const Header = extern struct {
+    count: u32,
+    block_start: u32,
+    num: u32,
+};
+
+const RawEntry = extern struct {
+    block_offset: u16,
+    num_offset: i16,
+    type: Inode.Type,
+    name_size: u16,
+};

src/file.zig

@@ -3,6 +3,8 @@
 const std = @import("std");
 const Io = std.Io;
 
+const Archive = @import("archive.zig");
+const DirEntry = @import("directory.zig");
 const ExtractionOptions = @import("options.zig");
 const Inode = @import("inode.zig");
 
@@ -10,17 +12,21 @@ const File = @This();
 
 alloc: std.mem.Allocator,
 
+archive: Archive,
+
 inode: Inode,
 name: []const u8,
 
 /// 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, in: Inode, name: []const u8) !File {
+pub fn init(alloc: std.mem.Allocator, archive: Archive, in: Inode, name: []const u8) !File {
     const new_name = try alloc.alloc(u8, name.len);
     @memcpy(new_name, name);
     return .{
         .alloc = alloc,
 
+        .archive = archive,
+
         .inode = in,
         .name = new_name,
     };
@@ -31,10 +37,10 @@ pub fn deinit(self: File) void {
 }
 
 pub fn open(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u8) !File {
-    _ = self;
-    _ = alloc;
-    _ = io;
-    _ = filepath;
+    switch (self.inode.hdr.inode_type) {
+        .dir, .ext_dir => {},
+        else => return Error.NotDirectory,
+    }
     return error.TODO;
 }
 
@@ -46,3 +52,12 @@ pub fn extract(self: File, alloc: std.mem.Allocator, io: Io, filepath: []const u
     _ = options;
     return error.TODO;
 }
+
+// Types
+
+pub const Error = error{
+    NotDirectory,
+    NotRegularFile,
+    NotSymlink,
+    NotDevice,
+};

src/inode.zig

@@ -87,7 +87,7 @@ pub const Data = union(Type) {
     ext_socket: misc.ExtIPC,
 };
 
-pub const Header = packed struct {
+pub const Header = extern struct {
     inode_type: Type,
     permissions: u16,
     uid_idx: u16,

src/inode_data/dir.zig

@@ -1,6 +1,6 @@
 const Reader = @import("std").Io.Reader;
 
-pub const Dir = packed struct {
+pub const Dir = extern struct {
     block_start: u32,
     hard_links: u32,
     size: u16,
@@ -14,7 +14,7 @@ pub const Dir = packed struct {
     }
 };
 
-pub const ExtDir = packed struct {
+pub const ExtDir = extern struct {
     hard_links: u32,
     size: u32,
     block_start: u32,
@@ -26,7 +26,7 @@ pub const ExtDir = packed struct {
 
     pub fn read(rdr: *Reader) !ExtDir {
         var d: ExtDir = undefined;
-        try rdr.readSliceEndian(Dir, @ptrCast(&d), .little);
+        try rdr.readSliceEndian(ExtDir, @ptrCast(&d), .little);
         return d;
     }
 };

src/inode_data/file.zig

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

src/inode_data/misc.zig

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

src/test.zig

@@ -13,10 +13,7 @@ test "Basics" {
     var fil = try Io.Dir.cwd().openFile(io, TestArchive, .{});
     defer fil.close(io);
     var sfs: Archive = try .init(io, fil, 0);
-    if (sfs.super != LinuxPATestCorrectSuperblock) {
-        std.debug.print("Superblock wrong\nShould be: {}\n\nis: {}\n", .{ LinuxPATestCorrectSuperblock, sfs.super });
-        return error.BadSuperblock;
-    }
+    try std.testing.expectEqualDeep(sfs.super, LinuxPATestCorrectSuperblock);
     const root_file = try sfs.root(alloc, io);
     defer root_file.deinit();
 }

src/util/metadata.zig

@@ -6,7 +6,7 @@ const StreamError = std.Io.Reader.StreamError;
 
 const Decompressor = @import("decompressor.zig");
 
-const BlockHeader = packed struct {
+const BlockHeader = packed struct(u16) {
     size: u15,
     uncompressed: bool,
 };