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/* str/diff.c - Differentiate two strings
* Copyright (C) 2001,2005 Bruce Guenter <bruce@untroubled.org>
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include <string.h>
#include "str.h"
/** Differentiate two strings.
The first non-zero difference between \c a and \c b is returned. If \c
a is longer than \c b and no differences are found up to the length of
\c b, then the return value is positive. If \c b is longer than \c a
and no differences are found up to the length of \c a, then the return
value is negative.
*/
int str_diff(const str* a, const str* b)
{
return str_diffb(a, b->s, b->len);
}
/** Differentiate a string and a C string. */
int str_diffs(const str* a, const char* b)
{
return str_diffb(a, b, strlen(b));
}
/** Differentiate a string and a binary block. */
int str_diffb(const str* a, const char* b, unsigned len)
{
unsigned max;
char* aptr;
max = a->len;
if (max > len) max = len;
for (aptr = a->s; max; ++aptr, ++b, --max)
if (*b - *aptr) return *b - *aptr;
if (a->len > len) return 1;
if (a->len < len) return -1;
return 0;
}
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