KeyValueCompression.java 文件源码

/**
 * Uncompresses a KeyValue from a DataInput and returns it.
 * 
 * @param in the DataInput
 * @param readContext the compressionContext to use.
 * @return an uncompressed KeyValue
 * @throws IOException
 */

public static KeyValue readKV(DataInput in, CompressionContext readContext)
    throws IOException {
  int keylength = WritableUtils.readVInt(in);
  int vlength = WritableUtils.readVInt(in);
  int tagsLength = WritableUtils.readVInt(in);
  int length = (int) KeyValue.getKeyValueDataStructureSize(keylength, vlength, tagsLength);

  byte[] backingArray = new byte[length];
  int pos = 0;
  pos = Bytes.putInt(backingArray, pos, keylength);
  pos = Bytes.putInt(backingArray, pos, vlength);

  // the row
  int elemLen = Compressor.uncompressIntoArray(backingArray,
      pos + Bytes.SIZEOF_SHORT, in, readContext.rowDict);
  checkLength(elemLen, Short.MAX_VALUE);
  pos = Bytes.putShort(backingArray, pos, (short)elemLen);
  pos += elemLen;

  // family
  elemLen = Compressor.uncompressIntoArray(backingArray,
      pos + Bytes.SIZEOF_BYTE, in, readContext.familyDict);
  checkLength(elemLen, Byte.MAX_VALUE);
  pos = Bytes.putByte(backingArray, pos, (byte)elemLen);
  pos += elemLen;

  // qualifier
  elemLen = Compressor.uncompressIntoArray(backingArray, pos, in,
      readContext.qualifierDict);
  pos += elemLen;

  // the rest
  in.readFully(backingArray, pos, length - pos);

  return new KeyValue(backingArray, 0, length);
}