@Override
public Block readBlock(Type type) throws IOException {
if (!rowGroupOpen) {
openRowGroup();
}
if (readOffset > 0) {
if (presentStream != null) {
// skip ahead the present bit reader, but count the set bits
// and use this as the skip size for the field readers
readOffset = presentStream.countBitsSet(readOffset);
}
for (StreamReader structField : structFields) {
structField.prepareNextRead(readOffset);
}
}
List<Type> typeParameters = type.getTypeParameters();
boolean[] nullVector = new boolean[nextBatchSize];
Block[] blocks = new Block[typeParameters.size()];
if (presentStream == null) {
for (int i = 0; i < typeParameters.size(); i++) {
StreamReader structField = structFields[i];
structField.prepareNextRead(nextBatchSize);
blocks[i] = structField.readBlock(typeParameters.get(i));
}
} else {
int nullValues = presentStream.getUnsetBits(nextBatchSize, nullVector);
if (nullValues != nextBatchSize) {
for (int i = 0; i < typeParameters.size(); i++) {
StreamReader structField = structFields[i];
structField.prepareNextRead(nextBatchSize - nullValues);
blocks[i] = structField.readBlock(typeParameters.get(i));
}
} else {
for (int i = 0; i < typeParameters.size(); i++) {
blocks[i] = typeParameters.get(i).createBlockBuilder(new BlockBuilderStatus(), 0).build();
}
}
}
// Build offsets for array block (null valued have no positions)
int[] offsets = new int[nextBatchSize];
offsets[0] = (nullVector[0] ? 0 : typeParameters.size());
for (int i = 1; i < nextBatchSize; i++) {
offsets[i] = offsets[i - 1] + (nullVector[i] ? 0 : typeParameters.size());
}
// Struct is represented as an array block holding an interleaved block
InterleavedBlock interleavedBlock = new InterleavedBlock(blocks);
ArrayBlock arrayBlock =
new ArrayBlock(
interleavedBlock,
Slices.wrappedIntArray(offsets),
0,
Slices.wrappedBooleanArray(nullVector));
readOffset = 0;
nextBatchSize = 0;
return arrayBlock;
}
