143 lines
4.1 KiB
C
143 lines
4.1 KiB
C
/*------------------------------------------------------------------
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* strfirstdiff_s.c
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*
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* November 2008, Bo Berry
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*
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* Copyright (c) 2008-2011 by Cisco Systems, Inc
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* All rights reserved.
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or
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* sell copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*------------------------------------------------------------------
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*/
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#include "safeclib_private.h"
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#include "safe_str_constraint.h"
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#include "safe_str_lib.h"
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/**
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* NAME
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* strfirstdiff_s
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*
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* SYNOPSIS
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* #include "safe_str_lib.h"
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* errno_t
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* strfirstdiff_s(const char *dest, rsize_t dmax,
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* const char *src, rsize_t *index)
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*
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* DESCRIPTION
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* Returns the index of the first character that is different
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* between dest and src. Index is valid only for OK.
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* The scanning stops at the first null in dest or src, or
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* after dmax characters.
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*
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* EXTENSION TO
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* ISO/IEC TR 24731, Programming languages, environments
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* and system software interfaces, Extensions to the C Library,
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* Part I: Bounds-checking interfaces
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*
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* INPUT PARAMETERS
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* dest pointer to string to compare against
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*
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* dmax restricted maximum length of string dest
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*
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* src pointer to the string to be compared to dest
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*
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* index pointer to returned index to first difference
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*
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* OUTPUT PARAMETERS
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* index returned index to first difference
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*
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* RUNTIME CONSTRAINTS
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* Neither dest nor src shall be a null pointer.
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* indicator shall not be a null pointer.
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* dmax shall not be 0.
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* dmax shall not be greater than RSIZE_MAX_STR.
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*
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* RETURN VALUE
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* index to first difference, when the return code is OK
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*
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* EOK index to first diff is returned
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* ESNODIFF no difference
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* ESNULLP NULL pointer
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* ESZEROL zero length
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* ESLEMAX length exceeds max limit
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*
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* ALSO SEE
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* strfirstchar_s(), strfirstsame_s(), strlastchar_s(),
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* strlastdiff_s(), strlastsame_s()
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*
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*/
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errno_t
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strfirstdiff_s (const char *dest, rsize_t dmax,
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const char *src, rsize_t *index)
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{
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const char *rp;
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if (index == NULL) {
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invoke_safe_str_constraint_handler("strfirstdiff_s: index is null",
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NULL, ESNULLP);
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return (ESNULLP);
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}
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*index = 0;
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if (dest == NULL) {
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invoke_safe_str_constraint_handler("strfirstdiff_s: dest is null",
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NULL, ESNULLP);
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return (ESNULLP);
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}
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if (src == NULL) {
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invoke_safe_str_constraint_handler("strfirstdiff_s: src is null",
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NULL, ESNULLP);
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return (ESNULLP);
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}
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if (dmax == 0 ) {
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invoke_safe_str_constraint_handler("strfirstdiff_s: dmax is 0",
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NULL, ESZEROL);
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return (ESZEROL);
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}
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if (dmax > RSIZE_MAX_STR) {
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invoke_safe_str_constraint_handler("strfirstdiff_s: dmax exceeds max",
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NULL, ESLEMAX);
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return (ESLEMAX);
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}
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/* hold reference point */
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rp = dest;
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while (*dest && *src && dmax) {
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if (*dest != *src) {
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*index = dest - rp;
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return (EOK);
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}
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dmax--;
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dest++;
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src++;
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}
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return (ESNODIFF);
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}
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