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Diffstat (limited to 'wsutil/adler32.c')
-rw-r--r-- | wsutil/adler32.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/wsutil/adler32.c b/wsutil/adler32.c new file mode 100644 index 0000000000..542876dc6f --- /dev/null +++ b/wsutil/adler32.c @@ -0,0 +1,61 @@ +/* adler32.c + * Compute the Adler32 checksum (RFC 1950) + * 2003 Tomas Kukosa + * Based on code from RFC 1950 (Chapter 9. Appendix: Sample code) + * + * $Id$ + * + * Wireshark - Network traffic analyzer + * By Gerald Combs <gerald@wireshark.org> + * Copyright 1998 Gerald Combs + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * 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 General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + */ + +#include <string.h> + +#include <glib.h> + +#include <epan/adler32.h> + +#define BASE 65521 /* largest prime smaller than 65536 */ + +/*--- update_adler32 --------------------------------------------------------*/ +guint32 update_adler32(guint32 adler, const guint8 *buf, size_t len) +{ + guint32 s1 = adler & 0xffff; + guint32 s2 = (adler >> 16) & 0xffff; + size_t n; + + for (n = 0; n < len; n++) { + s1 = (s1 + buf[n]) % BASE; + s2 = (s2 + s1) % BASE; + } + return (s2 << 16) + s1; +} + +/*--- adler32 ---------------------------------------------------------------*/ +guint32 adler32_bytes(const guint8 *buf, size_t len) +{ + return update_adler32(1, buf, len); +} + +/*--- adler32_str -----------------------------------------------------------*/ +guint32 adler32_str(const char *buf) +{ + return update_adler32(1, (const guint8*)buf, strlen(buf)); +} + +/*---------------------------------------------------------------------------*/ |