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/***
*strspn.c - find length of initial substring of chars from a control string
*
* Copyright (c) 1985-1993, Microsoft Corporation. All rights reserved.
*
*Purpose:
* defines strspn() - finds the length of the initial substring of
* a string consisting entirely of characters from a control string.
*
* defines strcspn()- finds the length of the initial substring of
* a string consisting entirely of characters not in a control string.
*
* defines strpbrk()- finds the index of the first character in a string
* that is not in a control string
*
*Revision History:
* 06-01-89 JCR C version created.
* 02-27-90 GJF Fixed calling type, #include <cruntime.h>, fixed
* copyright.
* 08-14-90 SBM Removed now redundant #include <stddef.h>
* 10-02-90 GJF New-style function declarators.
* 12-04-90 SRW Made it default to compiling for strspn
* 05-21-93 GJF Used unsigned char pointers to access control and
* source strings.
*
********************************************************************************
/* Determine which routine we're compiling for (default to STRSPN) */
#define _STRSPN 1
#define _STRCSPN 2
#define _STRPBRK 3
#if defined(SSTRCSPN)
#define ROUTINE _STRCSPN
#elif defined(SSTRPBRK)
#define ROUTINE _STRPBRK
#else
#define ROUTINE _STRSPN
#endif
#include <cruntime.h>
#include <string.h>
/***
*int strspn(string, control) - find init substring of control chars
*
*Purpose:
* Finds the index of the first character in string that does belong
* to the set of characters specified by control. This is
* equivalent to the length of the initial substring of string that
* consists entirely of characters from control. The '\0' character
* that terminates control is not considered in the matching process.
*
*Entry:
* char *string - string to search
* char *control - string containing characters not to search for
*
*Exit:
* returns index of first char in string not in control
*
*Exceptions:
*
*******************************************************************************/
/***
*int strcspn(string, control) - search for init substring w/o control chars
*
*Purpose:
* returns the index of the first character in string that belongs
* to the set of characters specified by control. This is equivalent
* to the length of the length of the initial substring of string
* composed entirely of characters not in control. Null chars not
* considered.
*
*Entry:
* char *string - string to search
* char *control - set of characters not allowed in init substring
*
*Exit:
* returns the index of the first char in string
* that is in the set of characters specified by control.
*
*Exceptions:
*
*******************************************************************************/
/***
*char *strpbrk(string, control) - scans string for a character from control
*
*Purpose:
* Finds the first occurence in string of any character from
* the control string.
*
*Entry:
* char *string - string to search in
* char *control - string containing characters to search for
*
*Exit:
* returns a pointer to the first character from control found
* in string.
* returns NULL if string and control have no characters in common.
*
*Exceptions:
*
*******************************************************************************/
/* Routine prototype */
#if (ROUTINE == _STRSPN)
size_t _CALLTYPE1 strspn (
#elif (ROUTINE == _STRCSPN)
size_t _CALLTYPE1 strcspn (
#else /* (ROUTINE == STRPBRK) */
char * _CALLTYPE1 strpbrk (
#endif
const char * string,
const char * control
)
{
const unsigned char *str = string;
const unsigned char *ctrl = control;
unsigned char map[32];
int count;
/* Clear out bit map */
for (count=0; count<32; count++)
map[count] = 0;
/* Set bits in control map */
while (*ctrl)
{
map[*ctrl >> 3] |= (1 << (*ctrl & 7));
ctrl++;
}
#if (ROUTINE == _STRSPN)
/* 1st char NOT in control map stops search */
if (*str)
{
count=0;
while (map[*str >> 3] & (1 << (*str & 7)))
{
count++;
str++;
}
return(count);
}
return(0);
#elif (ROUTINE == _STRCSPN)
/* 1st char in control map stops search */
count=0;
map[0] |= 1; /* null chars not considered */
while (!(map[*str >> 3] & (1 << (*str & 7))))
{
count++;
str++;
}
return(count);
#else /* (ROUTINE == _STRPBRK) */
/* 1st char in control map stops search */
while (*str)
{
if (map[*str >> 3] & (1 << (*str & 7)))
return((char *)str);
str++;
}
return(NULL);
#endif
}
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