windows-nt/Source/XPSP1/NT/base/crts/crtw32/string/i386/strspn.asm

	page	,132
	title	strspn - search for init substring of chars from control str
;***
;strspn.asm - find length of initial substring of chars from a control string
;
;	Copyright (c) 1985-2001, 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:
;	10-28-83  RN	initial version
;	06-30-87  SKS	Faster version -- also reentrant
;	05-18-88  SJM	Add model-independent (large model) ifdef
;	08-02-88  SJM	Created 386-specific version.
;	08-23-88  JCR	386 cleanup
;	10-10-88  JCR	Misc bug fixes
;	10-26-88  JCR	General cleanup for 386-only code
;	03-26-90  GJF	Changed to _stdcall. Also, fixed the copyright.
;	05-10-91  GJF	Back to _cdecl, sigh...
;	09-25-91  JCR	Build "strspn" if no other directives are given
;	01-17-92  GJF	Fixed build of "strspn".
;	01-17-95  GJF	Tuned.
;
;*******************************************************************************

	.xlist
	include cruntime.inc
	.list

page
;***
;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.
;
;	Algorithm:
;	int
;	strspn (string, control)
;		unsigned char *string, *control;
;	{
;		unsigned char map[32];
;		int count;
;
;		for (count = 0; count < 32; count++)
;			map[count] = 0;
;		while (*control)
;		{
;			map[*control >> 3] |= (1 << (*control & 7));
;			control++;
;		}
;		if (*string)
;		{
;			while (map[*string >> 3] & (1 << (*string & 7)))
;			{
;				count++;
;				string++;
;			}
;			return(count);
;		}
;		return(0);
;	}
;
;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
;
;Uses:
;
;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.
;
;	Algorithm:
;	int
;	strcspn (string, control)
;		unsigned char *string, *control;
;	{
;		unsigned char map[32];
;		int count;
;
;		for (count = 0; count < 32; count++)
;			map[count] = 0;
;		while (*control)
;		{
;			map[*control >> 3] |= (1 << (*control & 7));
;			control++;
;		}
;		map[0] |= 1;
;		while (!(map[*string >> 3] & (1 << (*string & 7))))
;		{
;			count++;
;			string++;
;		}
;		return(count);
;	}
;
;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.
;
;Uses:
;
;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.
;
;	Algorithm:
;	char *
;	strpbrk (string, control)
;		unsigned char *string, *control;
;	{
;		unsigned char map[32];
;		int count;
;
;		for (count = 0; count < 32; count++)
;			map[count] = 0;
;		while (*control)
;		{
;			map[*control >> 3] |= (1 << (*control & 7));
;			control++;
;		}
;		while (*string)
;		{
;			if (map[*string >> 3] & (1 << (*string & 7)))
;				return(string);
;			string++;
;		}
;		return(NULL);
;	}
;
;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.
;
;Uses:
;
;Exceptions:
;
;*******************************************************************************


ifdef SSTRCSPN

    _STRSPN_ equ <strcspn>

elseifdef SSTRPBRK

    _STRSPN_ equ <strpbrk>

else

; Default is to build strspn()

    SSTRSPN equ 1
    _STRSPN_ equ <strspn>

endif

% public  _STRSPN_

    CODESEG

_STRSPN_ proc \
	uses esi, \
	string:ptr byte, \
	control:ptr byte

; create and zero out char bit map

	xor	eax,eax
	push	eax		; 32
	push	eax
	push	eax
	push	eax		; 128
	push	eax
	push	eax
	push	eax
	push	eax		; 256

map	equ	[esp]

; Set control char bits in map

	mov	edx,control	; si = control string

	align	@WordSize
lab listnext			; init char bit map
	mov	al,[edx]
	or	al,al
	jz	short listdone
	inc	edx
	bts	map,eax
	jmp	short listnext

lab listdone

; Loop through comparing source string with control bits

	mov	esi,string	; si = string

_ifnd	SSTRPBRK <or	 ecx,-1> ; set ecx to -1

	align	@WordSize
lab dstnext

_ifnd	SSTRPBRK <inc	 ecx>

	mov	al,[esi]
	or	al,al
	jz	short dstdone
	inc	esi
	bt	map, eax

ifdef SSTRSPN
	jc	short dstnext	; strspn: found char, continue
elseifdef SSTRCSPN
	jnc	short dstnext	; strcspn: did not find char, continue
elseifdef SSTRPBRK
	jnc	short dstnext	; strpbrk: did not find char, continue
	lea	eax,[esi - 1]	; found char, return address of it
endif

; Return code

lab dstdone

_ifnd	SSTRPBRK <mov	eax,ecx> ; strspn/strcspn: return index

	add	esp,32

	ret			; _cdecl return

_STRSPN_ endp
	 end