private Integer seekToSubColumn(
CFMetaData metadata,
FileDataInput file,
ByteBuffer sblockId,
List<IndexHelper.IndexInfo> indexList)
throws IOException {
file.readInt(); // column count
/* get the various column ranges we have to read */
AbstractType comparator = metadata.comparator;
int index = IndexHelper.indexFor(sblockId, indexList, comparator, false);
if (index == indexList.size()) return null;
IndexHelper.IndexInfo indexInfo = indexList.get(index);
if (comparator.compare(sblockId, indexInfo.firstName) < 0) return null;
FileMark mark = file.mark();
FileUtils.skipBytesFully(file, indexInfo.offset);
while (file.bytesPastMark(mark) < indexInfo.offset + indexInfo.width) {
Integer dataLength = isSubBlockFound(metadata, file, sblockId);
if (dataLength == null) return null;
if (dataLength < 0) continue;
return dataLength;
}
return null;
}
/**
* Checks if the current column is the one we are looking for
*
* @param metadata
* @param file
* @param sblockId
* @return if > 0 the length to read from current file offset. if -1 not relevent. if null out of
* bounds
*/
private Integer isSubBlockFound(CFMetaData metadata, FileDataInput file, ByteBuffer sblockId)
throws IOException {
ByteBuffer name = ByteBufferUtil.readWithShortLength(file);
// Stop if we've gone too far (return null)
if (metadata.comparator.compare(name, sblockId) > 0) return null;
// verify column type;
int b = file.readUnsignedByte();
// skip ts (since we know block ids are unique)
long ts = file.readLong();
int sblockLength = file.readInt();
if (!name.equals(sblockId)
|| (b & ColumnSerializer.DELETION_MASK) != 0
|| (b & ColumnSerializer.EXPIRATION_MASK) != 0) {
FileUtils.skipBytesFully(file, sblockLength);
return -1;
}
return sblockLength;
}