snappy.StreamingDecompressor

StreamingDecompressor enables pull-based, chunk-by-chunk decompression of Snappy framed streams (.sz). Compressed byte slices are fed as they arrive from a socket, pipe, or file, and decompressed bytes are drained into caller-provided buffers.

pub const StreamingDecompressor = struct {
    allocator: std.mem.Allocator,
    options: DecompressionOptions,
    in_buffer: std.ArrayList(u8),
    out_buffer: std.ArrayList(u8),
    header_verified: bool,
    // ...
};

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Methods

init

pub fn init(allocator: std.mem.Allocator, options: DecompressionOptions) StreamingDecompressor

Initializes an incremental decompressor with the specified options.

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deinit

pub fn deinit(self: *StreamingDecompressor) void

Frees internal accumulation buffers.

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reset

pub fn reset(self: *StreamingDecompressor, new_options: DecompressionOptions) void

Clears buffers and resets state for decoding a new stream while retaining allocated capacity.

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feed

pub fn feed(self: *StreamingDecompressor, chunk: []const u8) Error!void

Appends chunk of compressed data to the internal input buffer, and processes any complete chunks present.

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take

pub fn take(self: *StreamingDecompressor, dst: []u8) Error!usize

Extracts available uncompressed bytes into dst. Returns the number of bytes written. If more decompressed data is available than can fit in dst, subsequent calls to take will continue draining the buffer until it returns 0.

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isFinished

pub fn isFinished(self: *const StreamingDecompressor) bool

Returns true when all input chunks have been completely decoded and all uncompressed data has been drained via take.

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Example Usage

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

pub fn processStream(allocator: std.mem.Allocator, chunks: [][]const u8) !void {
    var decompressor = snappy.StreamingDecompressor.init(allocator, .{
        .verifyChecksums = true,
    });
    defer decompressor.deinit();

    var output_buf: [4096]u8 = undefined;

    for (chunks) |chunk| {
        try decompressor.feed(chunk);

        while (true) {
            const count = try decompressor.take(&output_buf);
            if (count == 0) break;

            // Handle uncompressed bytes in output_buf[0..count]
            _ = count;
        }
    }
}