safec  2.1
Safe C Library - ISO TR24731 Bounds Checking Interface
strfirstdiff_s.c
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1 /*------------------------------------------------------------------
2  * strfirstdiff_s.c
3  *
4  * November 2008, Bo Berry
5  *
6  * Copyright (c) 2008-2011 by Cisco Systems, Inc
7  * All rights reserved.
8  *
9  * Permission is hereby granted, free of charge, to any person
10  * obtaining a copy of this software and associated documentation
11  * files (the "Software"), to deal in the Software without
12  * restriction, including without limitation the rights to use,
13  * copy, modify, merge, publish, distribute, sublicense, and/or
14  * sell copies of the Software, and to permit persons to whom the
15  * Software is furnished to do so, subject to the following
16  * conditions:
17  *
18  * The above copyright notice and this permission notice shall be
19  * included in all copies or substantial portions of the Software.
20  *
21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
22  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
23  * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
24  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
25  * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
26  * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
27  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
28  * OTHER DEALINGS IN THE SOFTWARE.
29  *------------------------------------------------------------------
30  */
31 
32 #include "safeclib_private.h"
33 #include "safe_str_constraint.h"
34 #include "safe_str_lib.h"
35 
36 
71  errno_t
72  strfirstdiff_s (const char *dest, rsize_t dmax,
73  const char *src, rsize_t *index)
74 {
75  const char *rp;
76 
77  if (index == NULL) {
78  invoke_safe_str_constraint_handler("strfirstdiff_s: index is null",
79  NULL, ESNULLP);
80  return (ESNULLP);
81  }
82  *index = 0;
83 
84  if (dest == NULL) {
85  invoke_safe_str_constraint_handler("strfirstdiff_s: dest is null",
86  NULL, ESNULLP);
87  return (ESNULLP);
88  }
89 
90  if (src == NULL) {
91  invoke_safe_str_constraint_handler("strfirstdiff_s: src is null",
92  NULL, ESNULLP);
93  return (ESNULLP);
94  }
95 
96  if (dmax == 0 ) {
97  invoke_safe_str_constraint_handler("strfirstdiff_s: dmax is 0",
98  NULL, ESZEROL);
99  return (ESZEROL);
100  }
101 
102  if (dmax > RSIZE_MAX_STR) {
103  invoke_safe_str_constraint_handler("strfirstdiff_s: dmax exceeds max",
104  NULL, ESLEMAX);
105  return (ESLEMAX);
106  }
107 
108  /* hold reference point */
109  rp = dest;
110 
111  while (*dest && *src && dmax) {
112 
113  if (*dest != *src) {
114  *index = dest - rp;
115  return (EOK);
116  }
117  dmax--;
118  dest++;
119  src++;
120  }
121 
122  return (ESNODIFF);
123 }
void invoke_safe_str_constraint_handler(const char *msg, void *ptr, errno_t error)
Invokes the currently set constraint handler or the default.
errno_t strfirstdiff_s(const char *dest, rsize_t dmax, const char *src, rsize_t *index)
Returns the index of the first character that is different between dest and src.