lz4.StreamingCompressor

StreamingCompressor enables push-based, chunk-by-chunk compression where data arrives in arbitrary increments and is emitted directly into a std.Io.Writer.

pub const StreamingCompressor = struct {
    allocator: std.mem.Allocator,
    stream: FrameCompressStream,
    header_written: bool = false,
    // ...
};

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Methods

init

pub fn init(allocator: std.mem.Allocator, opts: CompressionOptions) !StreamingCompressor

Initializes the streaming compressor, allocating necessary block buffers and state based on CompressionOptions.

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deinit

pub fn deinit(self: *StreamingCompressor) void

Releases all internal streaming buffers.

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write

pub fn write(self: *StreamingCompressor, chunk: []const u8, w: *std.Io.Writer) !void

Appends chunk to the compressor. If the accumulated input fills a complete block (as configured by blockMaxSize), the block is compressed and written immediately to w.

On the first call to write, the standard LZ4 Frame Header is automatically written to w.

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finish

pub fn finish(self: *StreamingCompressor, w: *std.Io.Writer) !void

Flushes any remaining buffered input as the final block, emits the standard 4-byte END_MARK (0x00000000), appends the 4-byte content checksum if enabled, and flushes w.

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Example Usage

const std = @import("std");
const lz4 = @import("lz4");

pub fn streamData(allocator: std.mem.Allocator, chunks: [][]const u8, file: std.fs.File) !void {
    var out_buffer: [65536]u8 = undefined;
    var writer = file.writer(&out_buffer);

    var compressor = try lz4.StreamingCompressor.init(allocator, .{
        .level = 1,
        .contentChecksum = true,
        .blockMaxSize = .max_64kb,
    });
    defer compressor.deinit();

    for (chunks) |chunk| {
        try compressor.write(chunk, &writer.interface);
    }

    try compressor.finish(&writer.interface);
}