ByteBufferUtils.java 文件源码

/**
 * Similar to {@link WritableUtils#readVLong(DataInput)} but reads from a
 * {@link ByteBuffer}.
 */
public static long readVLong(ByteBuffer in) {
  byte firstByte = in.get();
  int len = WritableUtils.decodeVIntSize(firstByte);
  if (len == 1) {
    return firstByte;
  }
  long i = 0;
  for (int idx = 0; idx < len-1; idx++) {
    byte b = in.get();
    i = i << 8;
    i = i | (b & 0xFF);
  }
  return (WritableUtils.isNegativeVInt(firstByte) ? (i ^ -1L) : i);
}