forked from osmocom/wireshark
62 lines
1.9 KiB
C
62 lines
1.9 KiB
C
/* adler32.c
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* Compute the Adler32 checksum (RFC 1950)
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* 2003 Tomas Kukosa
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* Based on code from RFC 1950 (Chapter 9. Appendix: Sample code)
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 1998 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <string.h>
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#include <glib.h>
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#include <epan/adler32.h>
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#define BASE 65521 /* largest prime smaller than 65536 */
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/*--- update_adler32 --------------------------------------------------------*/
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guint32 update_adler32(guint32 adler, const guint8 *buf, size_t len)
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{
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guint32 s1 = adler & 0xffff;
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guint32 s2 = (adler >> 16) & 0xffff;
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size_t n;
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for (n = 0; n < len; n++) {
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s1 = (s1 + buf[n]) % BASE;
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s2 = (s2 + s1) % BASE;
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}
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return (s2 << 16) + s1;
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}
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/*--- adler32 ---------------------------------------------------------------*/
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guint32 adler32_bytes(const guint8 *buf, size_t len)
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{
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return update_adler32(1, buf, len);
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}
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/*--- adler32_str -----------------------------------------------------------*/
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guint32 adler32_str(const char *buf)
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{
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return update_adler32(1, (const guint8*)buf, strlen(buf));
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}
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/*---------------------------------------------------------------------------*/
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