CompressionOptions

Options for brotli.compressWithOptions, Encoder and StreamingCompressor. Defined in src/compress/encode.zig and re-exported as brotli.CompressionOptions.

Definition

pub const Options = struct {
    quality: u32 = 11,
    lgwin: u32 = 22,
    mode: Mode = .generic,
    lgblock: u32 = 0,
    disable_literal_context_modeling: bool = false,
    size_hint: usize = 0,
    large_window: bool = false,
    npostfix: u32 = 0,
    ndirect: u32 = 0,
    progress: ?ProgressCallback = null,
    progress_ctx: ?*anyopaque = null,
};

Fields

Field	Type	Default	Description
quality	u32	11	Quality level 0..11; higher = better ratio, slower
lgwin	u32	22	Window bits 10..24 (clamped); bounds match distance
mode	Mode	.generic	.generic, .text, or .font analysis hint
lgblock	u32	0	Block-size hint (accepted for API parity)
disable_literal_context_modeling	bool	false	Accepted for API parity; encoder uses a fixed context layout
size_hint	usize	0	Expected total input size; improves progress reporting
large_window	bool	false	Accept LGWIN values up to 30 for interoperability
npostfix / ndirect	u32	0	Distance parameterization (accepted for API parity)
progress	?ProgressCallback	null	Called with (ctx, bytes_done, bytes_total) during streaming
progress_ctx	?*anyopaque	null	User pointer passed to the callback

Usage

const compressed = try brotli.compressWithOptions(allocator, data, .{
    .quality = 9,
    .lgwin = 22,
    .mode = .text,
    .size_hint = data.len,
});

Progress Callbacks

const Ctx = struct { total: usize = 0 };
fn onProgress(ctx: ?*anyopaque, done: usize, total: usize) void {
    const c: *Ctx = @ptrCast(@alignCast(ctx.?));
    c.total = done;
}

var opts = brotli.CompressionOptions{ .quality = 9, .size_hint = file_size };
opts.progress = onProgress;
opts.progress_ctx = &ctx;

Parameter Identifiers

For Encoder.setParameter(id, value) — mirrors the C enumeration:

Constant	Value	Controls
PARAM_MODE	0	mode
PARAM_QUALITY	1	quality
PARAM_LGWIN	2	lgwin
PARAM_LGBLOCK	3	lgblock
PARAM_DISABLE_LITERAL_CONTEXT_MODELING	4	context modeling flag
PARAM_SIZE_HINT	5	size_hint
PARAM_LARGE_WINDOW	6	large_window
PARAM_NPOSTFIX	7	npostfix
PARAM_NDIRECT	8	ndirect