func compress()

in compress.go [108:194]
84 lines of code
21 McCabe index (conditional complexity)

func compress(cc CompressionCodec, level int, data []byte) ([]byte, error) {
	switch cc {
	case CompressionNone:
		return data, nil
	case CompressionGZIP:
		var (
			err    error
			buf    bytes.Buffer
			writer *gzip.Writer
		)

		switch level {
		case CompressionLevelDefault:
			writer = gzipWriterPool.Get().(*gzip.Writer)
			defer gzipWriterPool.Put(writer)
			writer.Reset(&buf)
		case 1:
			writer = gzipWriterPoolForCompressionLevel1.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel1.Put(writer)
			writer.Reset(&buf)
		case 2:
			writer = gzipWriterPoolForCompressionLevel2.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel2.Put(writer)
			writer.Reset(&buf)
		case 3:
			writer = gzipWriterPoolForCompressionLevel3.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel3.Put(writer)
			writer.Reset(&buf)
		case 4:
			writer = gzipWriterPoolForCompressionLevel4.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel4.Put(writer)
			writer.Reset(&buf)
		case 5:
			writer = gzipWriterPoolForCompressionLevel5.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel5.Put(writer)
			writer.Reset(&buf)
		case 6:
			writer = gzipWriterPoolForCompressionLevel6.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel6.Put(writer)
			writer.Reset(&buf)
		case 7:
			writer = gzipWriterPoolForCompressionLevel7.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel7.Put(writer)
			writer.Reset(&buf)
		case 8:
			writer = gzipWriterPoolForCompressionLevel8.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel8.Put(writer)
			writer.Reset(&buf)
		case 9:
			writer = gzipWriterPoolForCompressionLevel9.Get().(*gzip.Writer)
			defer gzipWriterPoolForCompressionLevel9.Put(writer)
			writer.Reset(&buf)
		default:
			writer, err = gzip.NewWriterLevel(&buf, level)
			if err != nil {
				return nil, err
			}
		}
		if _, err := writer.Write(data); err != nil {
			return nil, err
		}
		if err := writer.Close(); err != nil {
			return nil, err
		}
		return buf.Bytes(), nil
	case CompressionSnappy:
		return snappy.Encode(data), nil
	case CompressionLZ4:
		writer := lz4WriterPool.Get().(*lz4.Writer)
		defer lz4WriterPool.Put(writer)

		var buf bytes.Buffer
		writer.Reset(&buf)

		if _, err := writer.Write(data); err != nil {
			return nil, err
		}
		if err := writer.Close(); err != nil {
			return nil, err
		}
		return buf.Bytes(), nil
	case CompressionZSTD:
		return zstdCompress(ZstdEncoderParams{level}, nil, data)
	default:
		return nil, PacketEncodingError{fmt.Sprintf("unsupported compression codec (%d)", cc)}
	}
}