/* * Copyright (C) 2012, 2016 higherfrequencytrading.com * Copyright (C) 2016 Roman Leventov * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation, either version 3 of the License. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program. If not, see <http://www.gnu.org/licenses/>. */ package net.openhft.chronicle.hash.impl.stage.entry; import net.openhft.chronicle.algo.hashing.LongHashFunction; import net.openhft.sg.StageRef; import net.openhft.sg.Staged; import static net.openhft.chronicle.hash.impl.stage.entry.ChecksumHashing.hash8To16Bytes; @Staged public class HashEntryChecksumStrategy implements ChecksumStrategy { @StageRef SegmentStages s; @StageRef HashEntryStages<?> e; @StageRef KeyHashCode h; @Override public void computeAndStoreChecksum() { int checksum = computeChecksum(); s.segmentBS.writeInt(e.entryEnd(), checksum); } @Override public int computeChecksum() { long keyHashCode = h.keyHashCode(); long keyEnd = e.keyEnd(); long len = e.entryEnd() - keyEnd; long checksum; if (len > 0) { long addr = s.tierBaseAddr + keyEnd; long payloadChecksum = LongHashFunction.xx_r39().hashMemory(addr, len); checksum = hash8To16Bytes(e.keySize, keyHashCode, payloadChecksum); } else { // non replicated ChronicleSet has no payload checksum = keyHashCode; } return (int) ((checksum >>> 32) ^ checksum); } @Override public boolean innerCheckSum() { int oldChecksum = storedChecksum(); int checksum = computeChecksum(); return oldChecksum == checksum; } @Override public int storedChecksum() { return s.segmentBS.readInt(e.entryEnd()); } @Override public long extraEntryBytes() { return CHECKSUM_STORED_BYTES; } }