encode() — netty Function Reference

Architecture documentation for the encode() function in FastLzFrameEncoder.java from the netty codebase.

Function java Buffer Allocators

Entity Profile

Buffer→ Allocators→ encode() — netty Function Reference

Dependency Diagram

graph TD
  64ae0fa9_8743_16dd_ed36_2ca16349d0a3["encode()"]
  6f3dd4d9_7eba_6bcc_7f72_548653d94248["FastLzFrameEncoder"]
  64ae0fa9_8743_16dd_ed36_2ca16349d0a3 -->|defined in| 6f3dd4d9_7eba_6bcc_7f72_548653d94248
  style 64ae0fa9_8743_16dd_ed36_2ca16349d0a3 fill:#6366f1,stroke:#818cf8,color:#fff

Relationship Graph

Source Code

codec-compression/src/main/java/io/netty/handler/codec/compression/FastLzFrameEncoder.java lines 110–172

    @Override
    protected void encode(ChannelHandlerContext ctx, ByteBuf in, ByteBuf out) throws Exception {
        final ByteBufChecksum checksum = this.checksum;

        for (;;) {
            if (!in.isReadable()) {
                return;
            }
            final int idx = in.readerIndex();
            final int length = Math.min(in.readableBytes(), MAX_CHUNK_LENGTH);

            final int outputIdx = out.writerIndex();
            out.setMedium(outputIdx, MAGIC_NUMBER);
            int outputOffset = outputIdx + CHECKSUM_OFFSET + (checksum != null ? 4 : 0);

            final byte blockType;
            final int chunkLength;
            if (length < MIN_LENGTH_TO_COMPRESSION) {
                blockType = BLOCK_TYPE_NON_COMPRESSED;

                out.ensureWritable(outputOffset + 2 + length);
                final int outputPtr = outputOffset + 2;

                if (checksum != null) {
                    checksum.reset();
                    checksum.update(in, idx, length);
                    out.setInt(outputIdx + CHECKSUM_OFFSET, (int) checksum.getValue());
                }
                out.setBytes(outputPtr, in, idx, length);
                chunkLength = length;
            } else {
                // try to compress
                if (checksum != null) {
                    checksum.reset();
                    checksum.update(in, idx, length);
                    out.setInt(outputIdx + CHECKSUM_OFFSET, (int) checksum.getValue());
                }

                final int maxOutputLength = calculateOutputBufferLength(length);
                out.ensureWritable(outputOffset + 4 + maxOutputLength);
                final int outputPtr = outputOffset + 4;
                final int compressedLength = compress(in, in.readerIndex(), length, out, outputPtr, level);

                if (compressedLength < length) {
                    blockType = BLOCK_TYPE_COMPRESSED;
                    chunkLength = compressedLength;

                    out.setShort(outputOffset, chunkLength);
                    outputOffset += 2;
                } else {
                    blockType = BLOCK_TYPE_NON_COMPRESSED;
                    out.setBytes(outputOffset + 2, in, idx, length);
                    chunkLength = length;
                }
            }
            out.setShort(outputOffset, length);

            out.setByte(outputIdx + OPTIONS_OFFSET,
                    blockType | (checksum != null ? BLOCK_WITH_CHECKSUM : BLOCK_WITHOUT_CHECKSUM));
            out.writerIndex(outputOffset + 2 + chunkLength);
            in.skipBytes(length);
        }
    }