Leaked source code of windows server 2003
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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.
; 06-12-01 PML inc->add 1, dec->sub 1 for Pentium 4 perf (vs7#267015)
;
;*******************************************************************************
.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
add edx,1
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 <add ecx,1>
mov al,[esi]
or al,al
jz short dstdone
add esi,1
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