rdblue commented on code in PR #3202: URL: https://github.com/apache/parquet-java/pull/3202#discussion_r2073888933
########## parquet-variant/src/main/java/org/apache/parquet/variant/VariantBuilder.java: ########## @@ -0,0 +1,590 @@ +/* + * 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.parquet.variant; + +import java.math.BigDecimal; +import java.math.BigInteger; +import java.nio.ByteBuffer; +import java.nio.ByteOrder; +import java.nio.charset.StandardCharsets; +import java.util.ArrayList; +import java.util.Arrays; +import java.util.Collections; +import java.util.Comparator; +import java.util.HashMap; + +/** + * Builder for creating Variant value and metadata. + */ +public class VariantBuilder { + /** + * Creates a VariantBuilder. + * @param allowDuplicateKeys if true, only the last occurrence of a duplicate key will be kept. + * Otherwise, an exception will be thrown. + */ + public VariantBuilder(boolean allowDuplicateKeys) { + this.allowDuplicateKeys = allowDuplicateKeys; + } + + /** + * @return the Variant value + */ + public Variant build() { + int numKeys = dictionaryKeys.size(); + // Use long to avoid overflow in accumulating lengths. + long dictionaryStringSize = 0; + for (byte[] key : dictionaryKeys) { + dictionaryStringSize += key.length; + } + // Determine the number of bytes required per offset entry. + // The largest offset is the one-past-the-end value, which is total string size. It's very + // unlikely that the number of keys could be larger, but incorporate that into the calculation + // in case of pathological data. + long maxSize = Math.max(dictionaryStringSize, numKeys); + int offsetSize = getMinIntegerSize((int) maxSize); + + int offsetStart = 1 + offsetSize; + int stringStart = offsetStart + (numKeys + 1) * offsetSize; + long metadataSize = stringStart + dictionaryStringSize; + + byte[] metadata = new byte[(int) metadataSize]; + int headerByte = VariantUtil.VERSION | ((offsetSize - 1) << 6); + VariantUtil.writeLong(metadata, 0, headerByte, 1); + VariantUtil.writeLong(metadata, 1, numKeys, offsetSize); + int currentOffset = 0; + for (int i = 0; i < numKeys; ++i) { + VariantUtil.writeLong(metadata, offsetStart + i * offsetSize, currentOffset, offsetSize); + byte[] key = dictionaryKeys.get(i); + System.arraycopy(key, 0, metadata, stringStart + currentOffset, key.length); + currentOffset += key.length; + } + VariantUtil.writeLong(metadata, offsetStart + numKeys * offsetSize, currentOffset, offsetSize); + return new Variant(Arrays.copyOfRange(writeBuffer, 0, writePos), metadata); Review Comment: If we aren't going to support reuse right away, then there is no reason to copy. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
