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Finished adding (untested) C decompression libraries.

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This commit is contained in:
Caleb J. Gardner
2026-02-08 06:52:14 -06:00
parent 61311433b9
commit 2760ad6ccb
4 changed files with 149 additions and 12 deletions
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README.md
+22
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@@ -26,3 +26,25 @@ Most features are present except for the following:
* xattrs are not applied on extraction
* Only zstd c library is implemented (all others result in error.TODO).
* When using Zig decompression libraries then lzo and lz4 compression types are unavailable. I don't _really_ plan on spending the time to find and validate a library since neither is popular.
## Building 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.
```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
+6 -1
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@@ -16,8 +16,13 @@ pub fn build(b: *std.Build) !void {
.link_libc = if (use_c_libs_option == true) true else false,
});
mod.addOptions("config", zig_squashfs_options);
if (use_c_libs_option == true)
if (use_c_libs_option == true) {
mod.linkSystemLibrary("zlib", .{});
mod.linkSystemLibrary("lzma", .{});
mod.linkSystemLibrary("minilzo", .{});
mod.linkSystemLibrary("lz4", .{});
mod.linkSystemLibrary("zstd", .{});
}
const unsquashfs_options = b.addOptions();
unsquashfs_options.addOption(std.SemanticVersion, "version", try std.SemanticVersion.parse(version_string_option orelse "0.0.0-testing"));
src/archive.zig
+5 -1
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@@ -3,6 +3,7 @@
const std = @import("std");
const File = std.fs.File;
const builtin = @import("builtin");
const Decomp = @import("decomp.zig");
const ExtractionOptions = @import("options.zig");
@@ -15,6 +16,8 @@ const Table = @import("table.zig").Table;
const MetadataReader = @import("util/metadata.zig");
const OffsetFile = @import("util/offset_file.zig");
const config = if (builtin.is_test) .{ .use_c_libs = true } else @import("config");
/// Information about a fragment section. Multiple fragments are contained in the block described by a single FragEntry.
/// The offset into the block and fragment size is stored in the file's inode.
pub const FragEntry = packed struct {
@@ -77,7 +80,8 @@ pub fn initAdvanced(alloc: std.mem.Allocator, fil: File, offset: u64, threads: u
.lzma => Decomp.lzmaDecompress,
.xz => Decomp.xzDecompress,
.zstd => Decomp.zstdDecompress,
else => return error.UnsupportedCompressionType,
.lz4 => if (config.use_c_libs) Decomp.cLz4 else return error.Lz4Unsupported,
.lzo => if (config.use_c_libs) Decomp.cLzo else return error.LzoUnsupported,
},
.super = super,
src/decomp.zig
+116 -10
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@@ -8,7 +8,13 @@ const builtin = @import("builtin");
const config = if (builtin.is_test) .{ .use_c_libs = true } else @import("config");
const c = @cImport({
@cInclude("zstd.h");
if (config.use_c_libs) {
@cInclude("zlib.h");
@cInclude("lzma.h");
@cInclude("lzo/minilzo.h");
@cInclude("lz4.h");
@cInclude("zstd.h");
}
});
pub const CompressionType = enum(u16) {
@@ -33,9 +39,15 @@ fn zigGzip(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
}
fn cGzip(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
_ = alloc;
_ = in;
_ = out;
return error.TODO;
var out_len: usize = out.len;
const res = c.uncompress(out.ptr, &out_len, in.ptr, in.len);
return switch (res) {
c.Z_OK => out_len,
c.Z_MEM_ERROR => error.NotEnoughMemory,
c.Z_BUF_ERROR => error.OutBufferTooSmall,
c.Z_DATA_ERROR => error.BadData,
else => error.UnknownResult,
};
}
pub const lzmaDecompress = if (config.use_c_libs) cLzma else zigLzma;
@@ -47,9 +59,65 @@ fn zigLzma(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
}
fn cLzma(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
_ = alloc;
_ = in;
_ = out;
return error.TODO;
var stream: c.lzma_stream = .{
.next_in = in.ptr,
.avail_in = in.len,
.next_out = out.ptr,
.avail_out = out.len,
};
var res = c.lzma_alone_decoder(&stream, in.len * 2);
switch (res) {
c.LZMA_OK => {},
c.LZMA_MEM_ERROR => return error.LzmaMemoryError,
c.LZMA_PROG_ERROR => return error.LzmaProgramError,
else => return error.UnknownResult,
}
defer c.lzma_end(&stream);
while (res == c.LZMA_OK)
res = c.lzma_code(&stream, c.LZMA_RUN);
return switch (res) {
c.LZMA_STREAM_END => stream.total_out,
c.LZMA_MEM_ERROR => error.LzmaMemoryError,
c.LZMA_MEMLIMIT_ERROR => error.LzmaMemoryLimit,
c.LZMA_FORMAT_ERROR => error.LzmaBadFormat,
c.LZMA_DATA_ERROR => error.LzmaDataCorrupt,
c.LZMA_BUF_ERROR => error.LzmaCannotProgress,
c.LZMA_PROG_ERROR => error.LzmaProgramError,
else => error.UnknownResult,
};
}
// pub const lzoDecompress = if (config.use_c_libs) cLzo else zigLzo;
// fn zigLzo(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
// _ = alloc;
// _ = in;
// _ = out;
// return error.LzoUnsupported;
// }
pub fn cLzo(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
_ = alloc;
var res = c.lzo_init();
if (res != 0) return error.LzoInitFailed;
var out_len: usize = out.len;
res = c.lzo1x_decompress(in.ptr, in.len, out.ptr, &out_len, null);
return switch (res) {
c.LZO_E_OK => out_len,
c.LZO_E_ERROR => error.LzoError,
c.LZO_E_OUT_OF_MEMORY => error.LzoOutOfMemory,
c.LZO_E_NOT_COMPRESSIBLE => error.LzoNotCompressible,
c.LZO_E_INPUT_OVERRUN => error.LzoInputOverrun,
c.LZO_E_OUTPUT_OVERRUN => error.LzoOutputOverrun,
c.LZO_E_LOOKBEHIND_OVERRUN => error.LzoLookbehindOverrun,
c.LZO_E_EOF_NOT_FOUND => error.LzoEofNotFound,
c.LZO_E_INPUT_NOT_CONSUMED => error.LzoInputNotConsumed,
c.LZO_E_NOT_YET_IMPLEMENTED => error.LzoNotYetImplemented,
c.LZO_E_INVALID_ARGUMENT => error.LzoInvalidArgument,
c.LZO_E_INVALID_ALIGNMENT => error.LzoInvalidAlignment,
c.LZO_E_OUTPUT_NOT_CONSUMED => error.LzoOutputNotConsumed,
c.LZO_E_INTERNAL_ERROR => error.LzoInternalError,
else => error.UnknownResult,
};
}
pub const xzDecompress = if (config.use_c_libs) cXz else zigXz;
@@ -61,9 +129,47 @@ fn zigXz(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
}
fn cXz(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
_ = alloc;
_ = in;
_ = out;
return error.TODO;
var stream: c.lzma_stream = .{
.next_in = in.ptr,
.avail_in = in.len,
.next_out = out.ptr,
.avail_out = out.len,
};
var res = c.lzma_stream_decoder(&stream, in.len * 2, 0);
switch (res) {
c.LZMA_OK => {},
c.LZMA_MEM_ERROR => return error.LzmaMemoryError,
c.LZMA_PROG_ERROR => return error.LzmaProgramError,
else => return error.UnknownResult,
}
defer c.lzma_end(&stream);
while (res == c.LZMA_OK)
res = c.lzma_code(&stream, c.LZMA_RUN);
return switch (res) {
c.LZMA_STREAM_END => stream.total_out,
c.LZMA_MEM_ERROR => error.LzmaMemoryError,
c.LZMA_MEMLIMIT_ERROR => error.LzmaMemoryLimit,
c.LZMA_FORMAT_ERROR => error.LzmaBadFormat,
c.LZMA_DATA_ERROR => error.LzmaDataCorrupt,
c.LZMA_BUF_ERROR => error.LzmaCannotProgress,
c.LZMA_PROG_ERROR => error.LzmaProgramError,
else => error.UnknownResult,
};
}
// pub const lz4Decompress = if (config.use_c_libs) cLz4 else zigLz4;
// fn zigLz4(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
// _ = alloc;
// _ = in;
// _ = out;
// return error.Lz4Unsupported;
// }
pub fn cLz4(alloc: std.mem.Allocator, in: []u8, out: []u8) anyerror!usize {
_ = alloc;
const res = c.LZ4_decompress_safe(in.ptr, out.ptr, @intCast(in.len), @intCast(out.len));
if (res > 0) return @abs(res); // TODO: Find out what error values it can return.
return error.Lz4DecompressFailed;
}
pub const zstdDecompress = if (config.use_c_libs) cZstd else zigZstd;