/**
* Writes the value and value length for non-first record.
*
* @param kv Key-value writer.
* @return The offset of the new record.
*/
private long writeValueAndLength(KvSource kv) throws SerDeException {
long valueOffset = writeBuffers.getWritePoint();
kv.writeValue(writeBuffers);
long tailOffset = writeBuffers.getWritePoint();
writeBuffers.writeVLong(tailOffset - valueOffset);
// LOG.info("Writing value at " + valueOffset + " length " + (tailOffset - valueOffset));
return tailOffset;
}
/**
* Adds a newly-written record to existing list.
*
* @param lrPtrOffset List record pointer offset.
* @param tailOffset New record offset.
*/
private void addRecordToList(long lrPtrOffset, long tailOffset) {
// Now, insert this record into the list.
long prevHeadOffset = writeBuffers.readNByteLong(lrPtrOffset, 5);
// LOG.info("Reading offset " + prevHeadOffset + " at " + lrPtrOffset);
assert prevHeadOffset < tailOffset; // We replace an earlier element, must have lower offset.
writeBuffers.writeFiveByteULong(lrPtrOffset, tailOffset);
// LOG.info("Writing offset " + tailOffset + " at " + lrPtrOffset);
writeBuffers.writeVLong(prevHeadOffset == 0 ? 0 : (tailOffset - prevHeadOffset));
}
/**
* Writes first value and lengths to finish the first record after the key has been written.
*
* @param kv Key-value writer.
* @param keyOffset
* @param keyLength Key length (already written).
* @param hashCode
* @return The offset of the new record.
*/
private long writeFirstValueRecord(KvSource kv, long keyOffset, int keyLength, int hashCode)
throws SerDeException {
long valueOffset = writeBuffers.getWritePoint();
kv.writeValue(writeBuffers);
long tailOffset = writeBuffers.getWritePoint();
int valueLength = (int) (tailOffset - valueOffset);
// LOG.info("Writing value at " + valueOffset + " length " + valueLength);
// In an unlikely case of 0-length key and value for the very first entry, we want to tell
// this apart from an empty value. We'll just advance one byte; this byte will be lost.
if (tailOffset == 0) {
writeBuffers.reserve(1);
++tailOffset;
}
// LOG.info("First tail offset " + writeBuffers.getWritePoint());
writeBuffers.writeVLong(valueLength);
writeBuffers.writeVLong(keyLength);
long lengthsLength = writeBuffers.getWritePoint() - tailOffset;
if (lengthsLength < 5) { // Reserve space for potential future list
writeBuffers.reserve(5 - (int) lengthsLength);
}
// Finally write the hash code.
writeBuffers.writeInt(keyOffset - 4, hashCode);
return tailOffset;
}