wuchong commented on a change in pull request #11651: URL: https://github.com/apache/flink/pull/11651#discussion_r411982907
########## File path: flink-table/flink-table-common/src/main/java/org/apache/flink/table/data/DecimalData.java ########## @@ -0,0 +1,260 @@ +/* + * 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.flink.table.data; + +import org.apache.flink.annotation.PublicEvolving; +import org.apache.flink.table.types.logical.DecimalType; + +import javax.annotation.Nonnull; +import javax.annotation.Nullable; + +import java.math.BigDecimal; +import java.math.BigInteger; +import java.math.RoundingMode; + +import static org.apache.flink.util.Preconditions.checkArgument; + +/** + * An internal data structure representing data of {@link DecimalType}. + * + * <p>This data structure is immutable and might store decimal values in a compact representation (as + * a long value) if values are small enough. + */ +@PublicEvolving +public final class DecimalData implements Comparable<DecimalData> { + + // member fields and static fields are package-visible, + // in order to be accessible for DecimalDataUtils + + static final int MAX_COMPACT_PRECISION = 18; + + /** + * Maximum number of decimal digits an Int can represent. (1e9 < Int.MaxValue < 1e10) + */ + static final int MAX_INT_DIGITS = 9; + + /** + * Maximum number of decimal digits a Long can represent. (1e18 < Long.MaxValue < 1e19) + */ + static final int MAX_LONG_DIGITS = 18; + + static final long[] POW10 = new long[MAX_COMPACT_PRECISION + 1]; + + static { + POW10[0] = 1; + for (int i = 1; i < POW10.length; i++) { + POW10[i] = 10 * POW10[i - 1]; + } + } + + // The semantics of the fields are as follows: + // - `precision` and `scale` represent the precision and scale of SQL decimal type + // - If `decimalVal` is set, it represents the whole decimal value + // - Otherwise, the decimal value is longVal/(10^scale). + // + // Note that the (precision, scale) must be correct. + // if precision > MAX_COMPACT_PRECISION, + // `decimalVal` represents the value. `longVal` is undefined + // otherwise, (longVal, scale) represents the value + // `decimalVal` may be set and cached + + final int precision; + final int scale; + + final long longVal; + BigDecimal decimalVal; + + // this constructor does not perform any sanity check. + DecimalData(int precision, int scale, long longVal, BigDecimal decimalVal) { + this.precision = precision; + this.scale = scale; + this.longVal = longVal; + this.decimalVal = decimalVal; + } + + // ------------------------------------------------------------------------------------------ + // Public Interfaces + // ------------------------------------------------------------------------------------------ + + /** + * Returns the <i>precision</i> of this {@link DecimalData}. + * + * <p>The precision is the number of digits in the unscaled value. + */ + public int precision() { + return precision; + } + + /** + * Returns the <i>scale</i> of this {@link DecimalData}. + */ + public int scale() { + return scale; + } + + /** + * Converts this {@link DecimalData} into an instance of {@link BigDecimal}. + */ + public BigDecimal toBigDecimal() { + BigDecimal bd = decimalVal; + if (bd == null) { + decimalVal = bd = BigDecimal.valueOf(longVal, scale); + } + return bd; + } + + /** + * Returns a long describing the <i>unscaled value</i> of this {@link DecimalData}. + * + * @throws ArithmeticException if this {@link DecimalData} does not exactly fit in a long. + */ + public long toUnscaledLong() { + if (isCompact()) { + return longVal; + } else { + return toBigDecimal().unscaledValue().longValueExact(); + } + } + + /** + * Returns a byte array describing the <i>unscaled value</i> of this {@link DecimalData}. + * + * @return the unscaled byte array of this {@link DecimalData}. + */ + public byte[] toUnscaledBytes() { + if (!isCompact()) { + return toBigDecimal().unscaledValue().toByteArray(); + } + + // big endian; consistent with BigInteger.toByteArray() + byte[] bytes = new byte[8]; Review comment: OK. Will do that in FLINK-16996. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected]
