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/*------------------------------------------------------------------
* strnlen_s.c
*
* October 2008, Bo Berry
*
* Copyright (c) 2008-2011 by Cisco Systems, Inc
* All rights reserved.
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*------------------------------------------------------------------
*/
#include "safeclib_private.h"
#include "safe_str_constraint.h"
#include "safe_str_lib.h"
/**
* NAME
* strnlen_s
*
* SYNOPSIS
* #include "safe_str_lib.h"
* rsize_t
* strnlen_s(const char *dest, rsize_t dmax)
*
* DESCRIPTION
* The strnlen_s function computes the length of the string pointed
* to by dest.
*
* SPECIFIED IN
* ISO/IEC TR 24731-1, Programming languages, environments
* and system software interfaces, Extensions to the C Library,
* Part I: Bounds-checking interfaces
*
* INPUT PARAMETERS
* dest pointer to string
*
* dmax restricted maximum length.
*
* OUTPUT PARAMETERS
* none
*
* RUNTIME CONSTRAINTS
* dest shall not be a null pointer
* dmax shall not be greater than RSIZE_MAX_STR
* dmax shall not equal zero
*
* RETURN VALUE
* The function returns the string length, excluding the terminating
* null character. If dest is NULL, then strnlen_s returns 0.
*
* Otherwise, the strnlen_s function returns the number of characters
* that precede the terminating null character. If there is no null
* character in the first dmax characters of dest then strnlen_s returns
* dmax. At most the first dmax characters of dest are accessed
* by strnlen_s.
*
* ALSO SEE
* strnterminate_s()
*
*/
rsize_t
strnlen_s (const char *dest, rsize_t dmax)
{
rsize_t count;
if (dest == NULL) {
return RCNEGATE(0);
}
if (dmax == 0) {
invoke_safe_str_constraint_handler("strnlen_s: dmax is 0",
NULL, ESZEROL);
return RCNEGATE(0);
}
if (dmax > RSIZE_MAX_STR) {
invoke_safe_str_constraint_handler("strnlen_s: dmax exceeds max",
NULL, ESLEMAX);
return RCNEGATE(0);
}
count = 0;
while (*dest && dmax) {
count++;
dmax--;
dest++;
}
return RCNEGATE(count);
}
EXPORT_SYMBOL(strnlen_s);
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