@Override
public int getIntArray(int row, int[] intArray) {
int startOffset = computeStartOffset(row);
int length = computeLength(startOffset);
for (int i = 0; i < length; i++) {
intArray[i] = rawDataReader.getInt(startOffset + i, 0);
}
return length;
}
public FixedBitSkipListSCMVReader(
File file,
int numDocs,
int totalNumValues,
int columnSizeInBits,
boolean signed,
boolean isMmap)
throws Exception {
this.numDocs = numDocs;
this.totalNumValues = totalNumValues;
float averageValuesPerDoc = totalNumValues / numDocs;
this.docsPerChunk = (int) (Math.ceil(PREFERRED_NUM_VALUES_PER_CHUNK / averageValuesPerDoc));
this.numChunks = (numDocs + docsPerChunk - 1) / docsPerChunk;
chunkOffsetHeaderSize = numChunks * SIZE_OF_INT * NUM_COLS_IN_HEADER;
bitsetSize = (totalNumValues + 7) / 8;
rawDataSize = Ints.checkedCast(((long) totalNumValues * columnSizeInBits + 7) / 8);
totalSize = chunkOffsetHeaderSize + bitsetSize + rawDataSize;
raf = new RandomAccessFile(file, "rw");
this.isMmap = isMmap;
if (isMmap) {
chunkOffsetsBuffer =
raf.getChannel().map(FileChannel.MapMode.READ_WRITE, 0, chunkOffsetHeaderSize).load();
bitsetBuffer =
raf.getChannel()
.map(FileChannel.MapMode.READ_WRITE, chunkOffsetHeaderSize, bitsetSize)
.load();
rawDataBuffer =
raf.getChannel()
.map(FileChannel.MapMode.READ_WRITE, chunkOffsetHeaderSize + bitsetSize, rawDataSize)
.load();
chunkOffsetsReader =
new FixedByteWidthRowColDataFileReader(
chunkOffsetsBuffer, numDocs, NUM_COLS_IN_HEADER, new int[] {SIZE_OF_INT});
customBitSet = CustomBitSet.withByteBuffer(bitsetSize, bitsetBuffer);
rawDataReader =
FixedBitWidthRowColDataFileReader.forByteBuffer(
rawDataBuffer,
totalNumValues,
1,
new int[] {columnSizeInBits},
new boolean[] {signed});
} else {
chunkOffsetsBuffer = ByteBuffer.allocateDirect(chunkOffsetHeaderSize);
raf.getChannel().read(chunkOffsetsBuffer);
chunkOffsetsReader =
new FixedByteWidthRowColDataFileReader(
chunkOffsetsBuffer, numDocs, NUM_COLS_IN_HEADER, new int[] {SIZE_OF_INT});
bitsetBuffer = ByteBuffer.allocateDirect(bitsetSize);
raf.getChannel().read(bitsetBuffer);
customBitSet = CustomBitSet.withByteBuffer(bitsetSize, bitsetBuffer);
rawDataBuffer = ByteBuffer.allocateDirect(rawDataSize);
raf.getChannel().read(rawDataBuffer);
rawDataReader =
FixedBitWidthRowColDataFileReader.forByteBuffer(
rawDataBuffer,
totalNumValues,
1,
new int[] {columnSizeInBits},
new boolean[] {signed});
raf.close();
}
}