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74 lines
1.9 KiB
74 lines
1.9 KiB
/*
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* Copyright (C) 2002-2003 Fhg Fokus
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*
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* This file is part of SEMS, a free SIP media server.
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*
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* SEMS is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version. This program is released under
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* the GPL with the additional exemption that compiling, linking,
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* and/or using OpenSSL is allowed.
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*
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* For a license to use the SEMS software under conditions
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* other than those described here, or to purchase support for this
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* software, please contact iptel.org by e-mail at the following addresses:
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* info@iptel.org
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*
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* SEMS is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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#ifndef __crc32calc_h__
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#define __crc32calc_h__
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static DWORD table[256];
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static bool inited;
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class CRC32Calc
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{
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public:
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CRC32Calc()
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{
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//Check if inited globally
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if (!inited)
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{
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for (DWORD i = 0; i < 256; ++i) {
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DWORD c = i;
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for (DWORD j = 0; j < 8; ++j) {
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if (c & 1) {
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c = 0xEDB88320 ^ (c >> 1);
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} else {
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c >>= 1;
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}
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}
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table[i] = c;
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}
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//Initied
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inited = true;
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}
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crc = 0;
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}
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DWORD Update(BYTE *data, DWORD size)
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{
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DWORD c = crc ^ 0xFFFFFFFF;
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for (DWORD i = 0; i < size; ++i)
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c = table[(c ^ data[i]) & 0xFF] ^ (c >> 8);
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crc = c ^ 0xFFFFFFFF;
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return crc;
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}
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private:
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DWORD crc;
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};
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#endif
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