docs / stdlib / wire

Compressor

cajeta.wire.Compressor is the compress stage of a byte-to-byte codec, the inverse of Decompressor. It carries no T, so it stays separate from Encoder<T>. Block containers (Parquet, ORC, Avro) call compress(src). HTTP content coding picks a level with compress(src, len, level) and streams a body through stream(level).

import cajeta.wire.Compressor;
import cajeta.wire.CompressStream;

// The stream a pass-through codec hands out: it returns what was written.
final class PassStream implements CompressStream {
    int8[] held;
    int64 n;

    PassStream() {
        this.held = heap int8[4096];
        this.n = 0;
    }

    public void write(int8[] src, int64 len) {
        int64 i = 0;
        while (i < len) {
            this.held[this.n + i] = src[i];
            i = i + 1;
        }
        this.n = this.n + len;
    }

    public #int8[] flush() {
        int8[] out #= CopyCompressor.take(this.held, this.n);
        this.n = 0;
        return #out;
    }

    public #int8[] finish() {
        return this.flush();
    }
}

// A pass-through codec showing the contract's shape.
public final class CopyCompressor implements Compressor {
    public CopyCompressor() { }

    static #int8[] take(int8[] src, int64 len) {
        int8[] out = heap int8[len];
        int64 i = 0;
        while (i < len) {
            out[i] = src[i];
            i = i + 1;
        }
        return #out;
    }

    public #int8[] compress(int8[] src) {
        return CopyCompressor.take(src, src.count());
    }

    public #int8[] compress(int8[] src, int64 len, int32 level) {
        return CopyCompressor.take(src, len);
    }

    public #CompressStream stream(int32 level) {
        return heap PassStream();
    }
}

Methods

⚑ = @EntryPoint

See also

• Decompressor, the inverse stage
• CompressStream, the streaming form
• Encoder, the typed (T-carrying) wire codec
• Source: runtime/src/cajeta/wire/Compressor.cajeta

Source: docs/stdlib/wire/Compressor.md · 1 min read · 144 words