private void readPageV1(DataPageV1 page) throws IOException {
this.pageValueCount = page.getValueCount();
ValuesReader rlReader = page.getRlEncoding().getValuesReader(descriptor, REPETITION_LEVEL);
ValuesReader dlReader;
// Initialize the decoders.
if (page.getDlEncoding() != Encoding.RLE && descriptor.getMaxDefinitionLevel() != 0) {
throw new UnsupportedOperationException("Unsupported encoding: " + page.getDlEncoding());
}
int bitWidth = BytesUtils.getWidthFromMaxInt(descriptor.getMaxDefinitionLevel());
this.defColumn = new VectorizedRleValuesReader(bitWidth);
dlReader = this.defColumn;
this.repetitionLevelColumn = new ValuesReaderIntIterator(rlReader);
this.definitionLevelColumn = new ValuesReaderIntIterator(dlReader);
try {
byte[] bytes = page.getBytes().toByteArray();
rlReader.initFromPage(pageValueCount, bytes, 0);
int next = rlReader.getNextOffset();
dlReader.initFromPage(pageValueCount, bytes, next);
next = dlReader.getNextOffset();
initDataReader(page.getValueEncoding(), bytes, next);
} catch (IOException e) {
throw new IOException("could not read page " + page + " in col " + descriptor, e);
}
}
@Override
public ValuesReader getValuesReader(ColumnDescriptor descriptor, ValuesType valuesType) {
int bitWidth = BytesUtils.getWidthFromMaxInt(getMaxLevel(descriptor, valuesType));
if (bitWidth == 0) {
return new ZeroIntegerValuesReader();
}
return new RunLengthBitPackingHybridValuesReader(bitWidth);
}
public static int readIntLittleEndianPaddedOnBitWidth(InputStream in, int bitWidth)
throws IOException {
int bytesWidth = paddedByteCountFromBits(bitWidth);
switch (bytesWidth) {
case 0:
return 0;
case 1:
return BytesUtils.readIntLittleEndianOnOneByte(in);
case 2:
return BytesUtils.readIntLittleEndianOnTwoBytes(in);
case 3:
return BytesUtils.readIntLittleEndianOnThreeBytes(in);
case 4:
return BytesUtils.readIntLittleEndian(in);
default:
throw new IOException(
String.format("Encountered bitWidth (%d) that requires more than 4 bytes", bitWidth));
}
}
private void readPageV2(DataPageV2 page) throws IOException {
this.pageValueCount = page.getValueCount();
this.repetitionLevelColumn =
createRLEIterator(
descriptor.getMaxRepetitionLevel(), page.getRepetitionLevels(), descriptor);
int bitWidth = BytesUtils.getWidthFromMaxInt(descriptor.getMaxDefinitionLevel());
this.defColumn = new VectorizedRleValuesReader(bitWidth);
this.definitionLevelColumn = new ValuesReaderIntIterator(this.defColumn);
this.defColumn.initFromBuffer(this.pageValueCount, page.getDefinitionLevels().toByteArray());
try {
initDataReader(page.getDataEncoding(), page.getData().toByteArray(), 0);
} catch (IOException e) {
throw new IOException("could not read page " + page + " in col " + descriptor, e);
}
}