forked from osmocom/wireshark
61 lines
1.5 KiB
C
61 lines
1.5 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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* 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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* SPDX-License-Identifier: GPL-2.0-or-later
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*/
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#include <string.h>
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#include <glib.h>
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#include <wsutil/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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/*
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* Editor modelines - https://www.wireshark.org/tools/modelines.html
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*
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* Local Variables:
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* c-basic-offset: 2
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* ex: set shiftwidth=2 tabstop=8 expandtab:
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* :indentSize=2:tabSize=8:noTabs=true:
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*/
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