Java tutorial
/** * Copyright 2016 Yahoo Inc. * * Licensed 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 com.yahoo.pulsar.utils; import io.netty.buffer.ByteBuf; public class NumberFormat { static void format(ByteBuf out, long num) { if (num == 0) { out.writeByte('0'); return; } // Long.MIN_VALUE needs special handling since abs(Long.MIN_VALUE) = abs(Long.MAX_VALUE) + 1 boolean encounteredMinValue = (num == Long.MIN_VALUE); if (num < 0) { out.writeByte('-'); num += encounteredMinValue ? 1 : 0; num *= -1; } // Putting the number in bytebuf in reverse order int start = out.writerIndex(); formatHelper(out, num); int end = out.writerIndex(); if (encounteredMinValue) { out.setByte(start, out.getByte(start) + 1); } // Reversing the digits end--; for (int i = 0; i <= (end - start) / 2; i++) { byte tmp = out.getByte(end - i); out.setByte(end - i, out.getByte(start + i)); out.setByte(start + i, tmp); } } static void formatHelper(ByteBuf out, long num) { while (num != 0) { out.writeByte((int) ('0' + num % 10)); num /= 10; } } }