Overall works, but currently is missing some features (see below). Extraction is a bit slow compared to the normal unsquashfs (from my very basic testing it's about ~3x slower). Only properly work on Linux, any other OSes probably won't work fully and are untested.

Build options

-Duse_c_libs

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

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.

-Dversion

Sets the version of unsquashfs shown when --version is passed.

Capabilities

Most features are present except for the following:

mod_time is not set on extraction
xattrs are not applied on extraction
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.

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. Due to this, you have to manually enable LZO decompression using -Dallow_lzo=true when building.

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 ''");

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;