/**
* lz4 壓縮
*
* @param value
* @return
*/
public static byte[] lz4(byte[] value) {
byte[] result = new byte[0];
try {
LZ4Factory factory = LZ4Factory.fastestInstance();
LZ4Compressor compressor = factory.fastCompressor();
//
final int INTEGER_BYTES = 4;
int length = value.length;
int maxCompressedLength = compressor.maxCompressedLength(length);
byte[] buff = new byte[INTEGER_BYTES + maxCompressedLength];
// 用4個byte紀錄原始長度
buff[0] = (byte) (length >>> 24);
buff[1] = (byte) (length >>> 16);
buff[2] = (byte) (length >>> 8);
buff[3] = (byte) (length);
// 壓縮後長度
int written = compressor.compress(value, 0, length, buff, INTEGER_BYTES, maxCompressedLength);
// 新長度=4+壓縮後長度
int newLength = INTEGER_BYTES + written;
result = new byte[newLength];
System.arraycopy(buff, 0, result, 0, newLength);
} catch (Exception ex) {
ex.printStackTrace();
}
return result;
}
/** Serialize the write. */
private ByteBuffer serialize(
final TableKey key, final TableValue value, final WriteOptions options) {
int size;
int optionSize = 0;
byte[] optionBuf = null;
byte[] keyData = key.serialize();
byte[] valueData = value.getBytes();
int maxCompressed = compressor.maxCompressedLength(valueData.length);
byte[] compressed = new byte[maxCompressed];
int actualCompressed =
compressor.compress(valueData, 0, valueData.length, compressed, 0, maxCompressed);
size =
(Short.SIZE / 8)
+ 4 * (Integer.SIZE / 8)
+ (Long.SIZE / 8)
+ keyData.length
+ actualCompressed;
if (options != null) {
optionBuf = OptionsSerializer.getBytes(options);
if (optionBuf != null) {
optionSize = optionBuf.length;
} else {
optionSize = 0;
}
size += optionSize;
}
ByteBuffer buf = ByteBuffer.allocateDirect(size);
buf.putLong(System.currentTimeMillis());
buf.putShort(MAGIC_NUMBER); // Magic number.
buf.putInt(keyData.length);
buf.putInt(valueData.length);
buf.putInt(actualCompressed);
buf.putInt(optionSize);
buf.put(keyData);
buf.put(compressed, 0, actualCompressed);
if (optionBuf != null) {
buf.put(optionBuf);
}
return buf;
}
