/***
*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

}
