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113 lines
2.9 KiB
C
113 lines
2.9 KiB
C
/* Copyright (C) 2007-2010 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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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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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* \file
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*
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* \author Victor Julien <victor@inliniac.net>
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*
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* Binary search utility functions
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*
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* \todo replace this by a better algo
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*/
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#include "suricata-common.h"
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#include "suricata.h"
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void BinSearchInit (void)
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{
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/* nothing no more */
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}
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/* Binary search.
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*
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* Returns:
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* - ptr to start of the match
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* - null if no match
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*/
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/* simple bin search modelled loosely after strstr */
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uint8_t *
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BinSearch(const uint8_t *haystack, size_t haystack_len,
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const uint8_t *needle, size_t needle_len)
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{
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const uint8_t *h, *n;
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const uint8_t *hmax = haystack + haystack_len;
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const uint8_t *nmax = needle + (needle_len - 1);
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if (needle_len == 0)
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return NULL;
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for (n = needle; haystack != hmax; haystack++) {
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if (*haystack != *n) {
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continue;
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}
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/* one byte needles */
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if (needle_len == 1)
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return (uint8_t *)haystack;
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for (h = haystack+1, n++; h != hmax; h++, n++) {
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//printf("h %c n %c\n", isprint(*h) ? *h : 'X', *n);
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if (*h != *n) {
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break;
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}
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/* if we run out of needle we fully matched */
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if (n == nmax) {
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return (uint8_t *)haystack;
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}
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}
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n = needle;
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}
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return NULL;
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}
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/* Caseless binary search. More expensive that the one that
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* respects case.
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*
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* Returns:
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* - ptr to start of the match
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* - null if no match
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*/
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uint8_t *
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BinSearchNocase(const uint8_t *haystack, size_t haystack_len,
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const uint8_t *needle, size_t needle_len)
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{
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const uint8_t *h, *n;
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const uint8_t *hmax = haystack + haystack_len;
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const uint8_t *nmax = needle + (needle_len - 1);
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if (needle_len == 0)
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return NULL;
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for (n = needle; haystack != hmax; haystack++) {
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if (*haystack != *n && *haystack != u8_tolower(*n)) {
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continue;
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}
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for (h = haystack+1, n++; h != hmax; h++, n++) {
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if (*h != *n && *h != u8_tolower(*n)) {
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break;
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}
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/* if we run out of needle we fully matched */
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if (n == nmax) {
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return (uint8_t *)haystack;
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}
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}
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n = needle;
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}
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return NULL;
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}
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