Java tutorial
/* * Copyright (c) 2015 Uber Technologies, Inc. * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ package com.uber.tchannel.checksum; import com.uber.tchannel.frames.CallFrame; import io.netty.buffer.ByteBuf; import java.util.zip.Adler32; public final class Checksums { public static boolean verifyChecksum(CallFrame msg) { return (calculateChecksum(msg) == msg.getChecksum()); } public static boolean verifyExistingChecksum(CallFrame msg, long checksum) { return (msg.getChecksum() == checksum); } public static long calculateChecksum(CallFrame msg) { return calculateChecksum(msg, 0L); } public static long calculateChecksum(CallFrame msg, long digestSeed) { // TODO: this is bad ByteBuf payloadCopy = msg.getPayload().slice(); byte[] payloadBytes = new byte[msg.getPayloadSize()]; payloadCopy.readBytes(payloadBytes); switch (msg.getChecksumType()) { case Adler32: Adler32 f = new Adler32(); f.update((int) digestSeed); f.update(payloadBytes); return f.getValue(); case FarmhashFingerPrint32: case NoChecksum: case CRC32C: default: return 0; } } }