Options & Integrity Checks

xz.zig provides structured configuration types for controlling block integrity checks, pre-filters, and safety bounds.

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xz.CheckType

Enumeration of supported XZ integrity check algorithms:

pub const CheckType = enum(u4) {
    none = 0x00,
    crc32 = 0x01,
    crc64 = 0x04,
    sha256 = 0x0A,

    pub fn checkSize(self: CheckType) usize;
    pub fn isValid(id: u4) bool;
};

Methods:

• checkSize(): Returns the byte size of the check field (0 for .none, 4 for .crc32, 8 for .crc64, 32 for .sha256).
• isValid(id): Validates whether a numeric 4-bit check ID corresponds to a recognized check type.

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xz.CompressOptions

Configuration struct passed to xz.compress(), xz.compressInto(), and xz.compressStream():

pub const CompressOptions = struct {
    check: CheckType = .crc64,
    enable_bcj_x86: bool = false,
    delta_distance: ?u8 = null,
    lzma2_options: lzma2.Options = .{},
};

Field Descriptions:

• check: Integrity check algorithm applied to each block. Default is .crc64 (standard XZ specification default).
• enable_bcj_x86: When true, prepends the x86 BCJ branch filter (0x04) to the filter chain to optimize executable machine code.
• delta_distance: When set to a value between 1 and 256, prepends the Delta filter (0x03) to the filter chain.
• lzma2_options: Options passed to the underlying lzma2.zig codec (compression level 0..9, dictionary size, etc.).

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xz.DecompressOptions

Configuration struct passed to xz.decompress(), xz.decompressInto(), and xz.decompressStream():

pub const DecompressOptions = struct {
    max_output_size: ?usize = null,
    dict_size_limit: ?u32 = null,
};

Field Descriptions:

• max_output_size: Maximum number of uncompressed bytes allowed before returning error.ExceededSizeLimit (defense against decompression bombs). Default is unlimited (std.math.maxInt(usize)).
• dict_size_limit: Maximum sliding dictionary memory window permitted. Default is 1 GiB.