strspn.c File Reference

#include <string.h>

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Macros
#define	_STRSPN   1
#define	_STRCSPN   2
#define	_STRPBRK   3
#define	ROUTINE   _STRSPN

Functions
size_t __cdecl	strspn (const char *string, const char *control)

Macro Definition Documentation

_STRCSPN

#define _STRCSPN   2

Definition at line 25 of file strspn.c.

_STRPBRK

#define _STRPBRK   3

Definition at line 26 of file strspn.c.

_STRSPN

#define _STRSPN   1

Definition at line 24 of file strspn.c.

ROUTINE

#define ROUTINE   _STRSPN

Definition at line 33 of file strspn.c.

Function Documentation

strspn()

size_t __cdecl strspn	(	const char *	string,
		const char *	control
	)

Definition at line 103 of file strspn.c.

{
        const unsigned char *str = (unsigned char const*)string;
        const unsigned char *ctrl = (unsigned char const*)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 == _STRCSPN */
 
        /* 1st char in control map stops search */
        while (*str)
        {
                if (map[*str >> 3] & (1 << (*str & 7)))
                        return((char *)str);
                str++;
        }
        return(NULL);
 
#endif  /* ROUTINE == _STRCSPN */
 
}