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