private void moveToPrevious() {
if (!previous.isValid()) {
throw new IllegalStateException(
"Can move back only once and not in first key in the block.");
}
STATE tmp = previous;
previous = current;
current = tmp;
// move after last key value
currentBuffer.position(current.nextKvOffset);
// Already decoded the tag bytes. We cache this tags into current state and also the total
// compressed length of the tags bytes. For the next time decodeNext() we don't need to decode
// the tags again. This might pollute the Data Dictionary what we use for the compression.
// When current.uncompressTags is false, we will just reuse the current.tagsBuffer and skip
// 'tagsCompressedLength' bytes of source stream.
// See in decodeTags()
current.tagsBuffer = previous.tagsBuffer;
current.tagsCompressedLength = previous.tagsCompressedLength;
current.uncompressTags = false;
// The current key has to be reset with the previous Cell
current.setKey(current.keyBuffer, current.memstoreTS);
previous.invalidate();
}
@Override
public int seekToKeyInBlock(Cell seekCell, boolean seekBefore) {
int rowCommonPrefix = 0;
int familyCommonPrefix = 0;
int qualCommonPrefix = 0;
previous.invalidate();
do {
int comp;
keyOnlyKV.setKey(current.keyBuffer, 0, current.keyLength);
if (current.lastCommonPrefix != 0) {
// The KV format has row key length also in the byte array. The
// common prefix
// includes it. So we need to subtract to find out the common prefix
// in the
// row part alone
rowCommonPrefix = Math.min(rowCommonPrefix, current.lastCommonPrefix - 2);
}
if (current.lastCommonPrefix <= 2) {
rowCommonPrefix = 0;
}
rowCommonPrefix += findCommonPrefixInRowPart(seekCell, keyOnlyKV, rowCommonPrefix);
comp = compareCommonRowPrefix(seekCell, keyOnlyKV, rowCommonPrefix);
if (comp == 0) {
comp = compareTypeBytes(seekCell, keyOnlyKV);
if (comp == 0) {
// Subtract the fixed row key length and the family key fixed length
familyCommonPrefix =
Math.max(
0,
Math.min(
familyCommonPrefix,
current.lastCommonPrefix - (3 + keyOnlyKV.getRowLength())));
familyCommonPrefix +=
findCommonPrefixInFamilyPart(seekCell, keyOnlyKV, familyCommonPrefix);
comp = compareCommonFamilyPrefix(seekCell, keyOnlyKV, familyCommonPrefix);
if (comp == 0) {
// subtract the rowkey fixed length and the family key fixed
// length
qualCommonPrefix =
Math.max(
0,
Math.min(
qualCommonPrefix,
current.lastCommonPrefix
- (3 + keyOnlyKV.getRowLength() + keyOnlyKV.getFamilyLength())));
qualCommonPrefix +=
findCommonPrefixInQualifierPart(seekCell, keyOnlyKV, qualCommonPrefix);
comp = compareCommonQualifierPrefix(seekCell, keyOnlyKV, qualCommonPrefix);
if (comp == 0) {
comp = CellComparator.compareTimestamps(seekCell, keyOnlyKV);
if (comp == 0) {
// Compare types. Let the delete types sort ahead of puts;
// i.e. types
// of higher numbers sort before those of lesser numbers.
// Maximum
// (255)
// appears ahead of everything, and minimum (0) appears
// after
// everything.
comp = (0xff & keyOnlyKV.getTypeByte()) - (0xff & seekCell.getTypeByte());
}
}
}
}
}
if (comp == 0) { // exact match
if (seekBefore) {
if (!previous.isValid()) {
// The caller (seekBefore) has to ensure that we are not at the
// first key in the block.
throw new IllegalStateException(
"Cannot seekBefore if "
+ "positioned at the first key in the block: key="
+ Bytes.toStringBinary(seekCell.getRowArray()));
}
moveToPrevious();
return 1;
}
return 0;
}
if (comp < 0) { // already too large, check previous
if (previous.isValid()) {
moveToPrevious();
} else {
return HConstants.INDEX_KEY_MAGIC; // using optimized index key
}
return 1;
}
// move to next, if more data is available
if (currentBuffer.hasRemaining()) {
previous.copyFromNext(current);
decodeNext();
current.setKey(current.keyBuffer, current.memstoreTS);
} else {
break;
}
} while (true);
// we hit the end of the block, not an exact match
return 1;
}
