nastra commented on code in PR #14800: URL: https://github.com/apache/iceberg/pull/14800#discussion_r2792855795
########## arrow/src/main/java/org/apache/iceberg/arrow/vectorized/parquet/VectorizedDeltaLengthByteArrayValuesReader.java: ########## @@ -0,0 +1,202 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ +package org.apache.iceberg.arrow.vectorized.parquet; + +import java.io.EOFException; +import java.io.IOException; +import java.nio.ByteBuffer; +import java.util.function.IntUnaryOperator; +import org.apache.arrow.vector.BaseVariableWidthVector; +import org.apache.arrow.vector.FieldVector; +import org.apache.parquet.bytes.ByteBufferInputStream; +import org.apache.parquet.column.values.ValuesReader; +import org.apache.parquet.io.ParquetDecodingException; +import org.apache.parquet.io.api.Binary; + +/** + * A {@link VectorizedValuesReader} implementation for the encoding type DELTA_LENGTH_BYTE_ARRAY. + * This is adapted from Spark's VectorizedDeltaLengthByteArrayReader. + * + * @see <a + * href="https://github.com/apache/parquet-format/blob/master/Encodings.md#delta-length-byte-array-delta_length_byte_array--6";> + * Parquet format encodings: DELTA_LENGTH_BYTE_ARRAY</a> + */ +public class VectorizedDeltaLengthByteArrayValuesReader extends ValuesReader + implements VectorizedValuesReader { + + private final VectorizedDeltaEncodedValuesReader lengthReader; + + private ByteBufferInputStream in; + private int[] lengths; + private ByteBuffer byteBuffer; + private int currentIndex; + + VectorizedDeltaLengthByteArrayValuesReader() { + lengthReader = new VectorizedDeltaEncodedValuesReader(); + } + + @Override + public void initFromPage(int valueCount, ByteBufferInputStream inputStream) throws IOException { + lengthReader.initFromPage(valueCount, inputStream); + // actual number of elements in the page may be less than the passed valueCount here due to + // nulls + lengths = lengthReader.readIntegers(lengthReader.getTotalValueCount(), 0); + + in = inputStream.remainingStream(); + currentIndex = 0; + } + + @Override + public Binary readBinary(int len) { + readValues(1, null, 0, x -> len, (f, i, v) -> byteBuffer = v); + return Binary.fromReusedByteBuffer(byteBuffer); + } + + Binary readBinaryForRow(int rowId) { + if (lengths[currentIndex] == 0) { + currentIndex++; + return Binary.EMPTY; + } + readValues(1, null, rowId, ignored -> lengths[currentIndex], (f, i, v) -> byteBuffer = v); + return Binary.fromReusedByteBuffer(byteBuffer); + } + + @Override + public void readBinary(int total, FieldVector vec, int rowId, boolean setArrowValidityVector) { + readValues( + total, + vec, + rowId, + x -> lengths[currentIndex], + (f, i, v) -> + ((BaseVariableWidthVector) vec) + .setSafe( + (int) i, v.array(), v.position() + v.arrayOffset(), v.limit() - v.position())); + } + + @SuppressWarnings("UnusedVariable") + private void readValues( + int total, + FieldVector vec, + int rowId, + IntUnaryOperator getLength, + BinaryOutputWriter outputWriter) { + ByteBuffer buffer; + for (int i = 0; i < total; i++) { + int length = getLength.applyAsInt(rowId + i); + try { + if (length < 0) { + throw new IllegalStateException("Invalid length: " + length); + } + buffer = in.slice(length); + } catch (EOFException e) { + throw new ParquetDecodingException("Failed to read " + length + " bytes"); + } + outputWriter.write(vec, rowId + i, buffer); + currentIndex++; + } + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public boolean readBoolean() { + throw new UnsupportedOperationException("readBoolean is not supported"); + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public byte readByte() { + throw new UnsupportedOperationException("readByte is not supported"); + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public short readShort() { + throw new UnsupportedOperationException("readShort is not supported"); + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public int readInteger() { + throw new UnsupportedOperationException("readInteger is not supported"); + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public long readLong() { + throw new UnsupportedOperationException("readLong is not supported"); + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public float readFloat() { + throw new UnsupportedOperationException("readFloat is not supported"); + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public double readDouble() { + throw new UnsupportedOperationException("readDouble is not supported"); + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public void readIntegers(int total, FieldVector vec, int rowId) { + throw new UnsupportedOperationException("readIntegers is not supported"); + } + + /** DELTA_LENGTH_BYTE_ARRAY only supports BINARY */ + @Override + public void readLongs(int total, FieldVector vec, int rowId) { + throw new UnsupportedOperationException("readLongs is not supported"); Review Comment: rather than having to throw UOE in each subclass we should probably instead do this in one single place -- This is an automated message from the Apache Git Service. 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