assert CodecUtil.headerLength(codecNameDat) == vectorsStream.getFilePointer();
packedIntsVersion = vectorsStream.readVInt();
chunkSize = vectorsStream.readVInt();
decompressor = compressionMode.newDecompressor();
this.reader = new BlockPackedReaderIterator(vectorsStream, packedIntsVersion, BLOCK_SIZE, 0);
success = true;
} finally {
if (!success) {
IOUtils.closeWhileHandlingException(this, indexStream);