/*
 * 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 com.alipay.sofa.jraft.util;

import java.util.zip.Checksum;

/**
 * CRC64
 * @author boyan(boyan@antfin.com)
 *
 */
public class CRC64 implements Checksum {
    /**
     * CRC-64-ECMA-182
     *
     * <pre>
     * The polynomial code used is 0x42F0E1EBA9EA3693 (CRC64-ECMA-182)
     * x64+x62+x57+x55+x54+x53+x52+x47+x46+x45+x40+x39+x38+x37+x35+x33+
     * x32+x31+x29+x27+x24+x23+x22+x21+x19+x17+x13+x12+x10+x9+x7+x4+x+1
     * </pre>
     *
     * poly=0x42f0e1eba9ea3693 init=0x0 refin=false refout=false xorout=0x0
     *
     * @see <a href="http://en.wikipedia.org/wiki/Cyclic_redundancy_check">http://en.wikipedia.org/wiki/Cyclic_redundancy_check</a>
     * @see <a href="http://reveng.sourceforge.net/crc-catalogue/17plus.htm">http://reveng.sourceforge.net/crc-catalogue/17plus.htm</a>
     */
    private static final long[] CRC_TABLE = new long[] { 0x0000000000000000L, 0x42F0E1EBA9EA3693L, 0x85E1C3D753D46D26L,
            0xC711223CFA3E5BB5L, 0x493366450E42ECDFL, 0x0BC387AEA7A8DA4CL, 0xCCD2A5925D9681F9L, 0x8E224479F47CB76AL,
            0x9266CC8A1C85D9BEL, 0xD0962D61B56FEF2DL, 0x17870F5D4F51B498L, 0x5577EEB6E6BB820BL, 0xDB55AACF12C73561L,
            0x99A54B24BB2D03F2L, 0x5EB4691841135847L, 0x1C4488F3E8F96ED4L, 0x663D78FF90E185EFL, 0x24CD9914390BB37CL,
            0xE3DCBB28C335E8C9L, 0xA12C5AC36ADFDE5AL, 0x2F0E1EBA9EA36930L, 0x6DFEFF5137495FA3L, 0xAAEFDD6DCD770416L,
            0xE81F3C86649D3285L, 0xF45BB4758C645C51L, 0xB6AB559E258E6AC2L, 0x71BA77A2DFB03177L, 0x334A9649765A07E4L,
            0xBD68D2308226B08EL, 0xFF9833DB2BCC861DL, 0x388911E7D1F2DDA8L, 0x7A79F00C7818EB3BL, 0xCC7AF1FF21C30BDEL,
            0x8E8A101488293D4DL, 0x499B3228721766F8L, 0x0B6BD3C3DBFD506BL, 0x854997BA2F81E701L, 0xC7B97651866BD192L,
            0x00A8546D7C558A27L, 0x4258B586D5BFBCB4L, 0x5E1C3D753D46D260L, 0x1CECDC9E94ACE4F3L, 0xDBFDFEA26E92BF46L,
            0x990D1F49C77889D5L, 0x172F5B3033043EBFL, 0x55DFBADB9AEE082CL, 0x92CE98E760D05399L, 0xD03E790CC93A650AL,
            0xAA478900B1228E31L, 0xE8B768EB18C8B8A2L, 0x2FA64AD7E2F6E317L, 0x6D56AB3C4B1CD584L, 0xE374EF45BF6062EEL,
            0xA1840EAE168A547DL, 0x66952C92ECB40FC8L, 0x2465CD79455E395BL, 0x3821458AADA7578FL, 0x7AD1A461044D611CL,
            0xBDC0865DFE733AA9L, 0xFF3067B657990C3AL, 0x711223CFA3E5BB50L, 0x33E2C2240A0F8DC3L, 0xF4F3E018F031D676L,
            0xB60301F359DBE0E5L, 0xDA050215EA6C212FL, 0x98F5E3FE438617BCL, 0x5FE4C1C2B9B84C09L, 0x1D14202910527A9AL,
            0x93366450E42ECDF0L, 0xD1C685BB4DC4FB63L, 0x16D7A787B7FAA0D6L, 0x5427466C1E109645L, 0x4863CE9FF6E9F891L,
            0x0A932F745F03CE02L, 0xCD820D48A53D95B7L, 0x8F72ECA30CD7A324L, 0x0150A8DAF8AB144EL, 0x43A04931514122DDL,
            0x84B16B0DAB7F7968L, 0xC6418AE602954FFBL, 0xBC387AEA7A8DA4C0L, 0xFEC89B01D3679253L, 0x39D9B93D2959C9E6L,
            0x7B2958D680B3FF75L, 0xF50B1CAF74CF481FL, 0xB7FBFD44DD257E8CL, 0x70EADF78271B2539L, 0x321A3E938EF113AAL,
            0x2E5EB66066087D7EL, 0x6CAE578BCFE24BEDL, 0xABBF75B735DC1058L, 0xE94F945C9C3626CBL, 0x676DD025684A91A1L,
            0x259D31CEC1A0A732L, 0xE28C13F23B9EFC87L, 0xA07CF2199274CA14L, 0x167FF3EACBAF2AF1L, 0x548F120162451C62L,
            0x939E303D987B47D7L, 0xD16ED1D631917144L, 0x5F4C95AFC5EDC62EL, 0x1DBC74446C07F0BDL, 0xDAAD56789639AB08L,
            0x985DB7933FD39D9BL, 0x84193F60D72AF34FL, 0xC6E9DE8B7EC0C5DCL, 0x01F8FCB784FE9E69L, 0x43081D5C2D14A8FAL,
            0xCD2A5925D9681F90L, 0x8FDAB8CE70822903L, 0x48CB9AF28ABC72B6L, 0x0A3B7B1923564425L, 0x70428B155B4EAF1EL,
            0x32B26AFEF2A4998DL, 0xF5A348C2089AC238L, 0xB753A929A170F4ABL, 0x3971ED50550C43C1L, 0x7B810CBBFCE67552L,
            0xBC902E8706D82EE7L, 0xFE60CF6CAF321874L, 0xE224479F47CB76A0L, 0xA0D4A674EE214033L, 0x67C58448141F1B86L,
            0x253565A3BDF52D15L, 0xAB1721DA49899A7FL, 0xE9E7C031E063ACECL, 0x2EF6E20D1A5DF759L, 0x6C0603E6B3B7C1CAL,
            0xF6FAE5C07D3274CDL, 0xB40A042BD4D8425EL, 0x731B26172EE619EBL, 0x31EBC7FC870C2F78L, 0xBFC9838573709812L,
            0xFD39626EDA9AAE81L, 0x3A28405220A4F534L, 0x78D8A1B9894EC3A7L, 0x649C294A61B7AD73L, 0x266CC8A1C85D9BE0L,
            0xE17DEA9D3263C055L, 0xA38D0B769B89F6C6L, 0x2DAF4F0F6FF541ACL, 0x6F5FAEE4C61F773FL, 0xA84E8CD83C212C8AL,
            0xEABE6D3395CB1A19L, 0x90C79D3FEDD3F122L, 0xD2377CD44439C7B1L, 0x15265EE8BE079C04L, 0x57D6BF0317EDAA97L,
            0xD9F4FB7AE3911DFDL, 0x9B041A914A7B2B6EL, 0x5C1538ADB04570DBL, 0x1EE5D94619AF4648L, 0x02A151B5F156289CL,
            0x4051B05E58BC1E0FL, 0x87409262A28245BAL, 0xC5B073890B687329L, 0x4B9237F0FF14C443L, 0x0962D61B56FEF2D0L,
            0xCE73F427ACC0A965L, 0x8C8315CC052A9FF6L, 0x3A80143F5CF17F13L, 0x7870F5D4F51B4980L, 0xBF61D7E80F251235L,
            0xFD913603A6CF24A6L, 0x73B3727A52B393CCL, 0x31439391FB59A55FL, 0xF652B1AD0167FEEAL, 0xB4A25046A88DC879L,
            0xA8E6D8B54074A6ADL, 0xEA16395EE99E903EL, 0x2D071B6213A0CB8BL, 0x6FF7FA89BA4AFD18L, 0xE1D5BEF04E364A72L,
            0xA3255F1BE7DC7CE1L, 0x64347D271DE22754L, 0x26C49CCCB40811C7L, 0x5CBD6CC0CC10FAFCL, 0x1E4D8D2B65FACC6FL,
            0xD95CAF179FC497DAL, 0x9BAC4EFC362EA149L, 0x158E0A85C2521623L, 0x577EEB6E6BB820B0L, 0x906FC95291867B05L,
            0xD29F28B9386C4D96L, 0xCEDBA04AD0952342L, 0x8C2B41A1797F15D1L, 0x4B3A639D83414E64L, 0x09CA82762AAB78F7L,
            0x87E8C60FDED7CF9DL, 0xC51827E4773DF90EL, 0x020905D88D03A2BBL, 0x40F9E43324E99428L, 0x2CFFE7D5975E55E2L,
            0x6E0F063E3EB46371L, 0xA91E2402C48A38C4L, 0xEBEEC5E96D600E57L, 0x65CC8190991CB93DL, 0x273C607B30F68FAEL,
            0xE02D4247CAC8D41BL, 0xA2DDA3AC6322E288L, 0xBE992B5F8BDB8C5CL, 0xFC69CAB42231BACFL, 0x3B78E888D80FE17AL,
            0x7988096371E5D7E9L, 0xF7AA4D1A85996083L, 0xB55AACF12C735610L, 0x724B8ECDD64D0DA5L, 0x30BB6F267FA73B36L,
            0x4AC29F2A07BFD00DL, 0x08327EC1AE55E69EL, 0xCF235CFD546BBD2BL, 0x8DD3BD16FD818BB8L, 0x03F1F96F09FD3CD2L,
            0x41011884A0170A41L, 0x86103AB85A2951F4L, 0xC4E0DB53F3C36767L, 0xD8A453A01B3A09B3L, 0x9A54B24BB2D03F20L,
            0x5D45907748EE6495L, 0x1FB5719CE1045206L, 0x919735E51578E56CL, 0xD367D40EBC92D3FFL, 0x1476F63246AC884AL,
            0x568617D9EF46BED9L, 0xE085162AB69D5E3CL, 0xA275F7C11F7768AFL, 0x6564D5FDE549331AL, 0x279434164CA30589L,
            0xA9B6706FB8DFB2E3L, 0xEB46918411358470L, 0x2C57B3B8EB0BDFC5L, 0x6EA7525342E1E956L, 0x72E3DAA0AA188782L,
            0x30133B4B03F2B111L, 0xF7021977F9CCEAA4L, 0xB5F2F89C5026DC37L, 0x3BD0BCE5A45A6B5DL, 0x79205D0E0DB05DCEL,
            0xBE317F32F78E067BL, 0xFCC19ED95E6430E8L, 0x86B86ED5267CDBD3L, 0xC4488F3E8F96ED40L, 0x0359AD0275A8B6F5L,
            0x41A94CE9DC428066L, 0xCF8B0890283E370CL, 0x8D7BE97B81D4019FL, 0x4A6ACB477BEA5A2AL, 0x089A2AACD2006CB9L,
            0x14DEA25F3AF9026DL, 0x562E43B4931334FEL, 0x913F6188692D6F4BL, 0xD3CF8063C0C759D8L, 0x5DEDC41A34BBEEB2L,
            0x1F1D25F19D51D821L, 0xD80C07CD676F8394L, 0x9AFCE626CE85B507L };
    private long                crc       = 0;

    @Override
    public void update(final int b) {
        update((byte) (b & 0xFF));
    }

    public void update(final byte b) {
        final int tab_index = ((int) (this.crc >> 56) ^ b) & 0xFF;
        this.crc = CRC_TABLE[tab_index] ^ (this.crc << 8);
    }

    @Override
    public void update(final byte[] buffer, final int offset, int length) {
        for (int i = offset; length > 0; length--) {
            update(buffer[i++]);
        }
    }

    public void update(final byte[] buffer) {
        for (int i = 0; i < buffer.length; i++) {
            update(buffer[i]);
        }
    }

    @Override
    public long getValue() {
        return this.crc;
    }

    @Override
    public void reset() {
        this.crc = 0;
    }

}
