/**
* Serializes a long to a binary stream with zero-compressed encoding. For -112 <= i <= 127,
* only one byte is used with the actual value. For other values of i, the first byte value
* indicates whether the long is positive or negative, and the number of bytes that follow. If
* the first byte value v is between -113 and -120, the following long is positive, with number
* of bytes that follow are -(v+112). If the first byte value v is between -121 and -128, the
* following long is negative, with number of bytes that follow are -(v+120). Bytes are stored
* in the high-non-zero-byte-first order.
*
* @param buffer DrillBuf to write to
* @param i Long to be serialized
*/
public static void writeVLong(DrillBuf buffer, int start, int end, long i) {
int availableBytes = (end - start);
if (availableBytes < getVIntSize(i)) {
throw new NumberFormatException(
"Expected "
+ getVIntSize(i)
+ " bytes but the buffer '"
+ DrillStringUtils.toBinaryString(buffer, start, end)
+ "' has only "
+ availableBytes
+ " bytes.");
}
buffer.writerIndex(start);
if (i >= -112 && i <= 127) {
buffer.writeByte((byte) i);
return;
}
int len = -112;
if (i < 0) {
i ^= -1L; // take one's complement'
len = -120;
}
long tmp = i;
while (tmp != 0) {
tmp = tmp >> 8;
len--;
}
buffer.writeByte((byte) len);
len = (len < -120) ? -(len + 120) : -(len + 112);
for (int idx = len; idx != 0; idx--) {
int shiftbits = (idx - 1) * 8;
long mask = 0xFFL << shiftbits;
buffer.writeByte((byte) ((i & mask) >> shiftbits));
}
}
@Override
public DrillBuf slice(int index, int length) {
DrillBuf buf = new DrillBuf(this, index, length);
buf.writerIndex = length;
return buf;
}