Windows NT 4.0 source code leak
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294 lines
5.8 KiB

page ,132
title stricmp
;***
;stricmp.asm - contains case-insensitive string comparision routine
; _stricmp/_strcmpi
;
; Copyright (c) 1985-1995, Microsoft Corporation. All rights reserved.
;
;Purpose:
; contains _stricmpi(), also known as _strcmpi()
;
;Revision History:
; 05-18-88 SJM Add model-independent (large model) ifdef
; 08-04-88 SJM convert to cruntime/ add 32-bit support
; 08-23-88 JCR Minor 386 cleanup
; 10-10-88 JCR Added strcmpi() entry for compatiblity with early revs
; 10-25-88 JCR General cleanup for 386-only code
; 10-27-88 JCR Shuffled regs so no need to save/restore ebx
; 03-23-90 GJF Changed to _stdcall. Also, fixed the copyright.
; 01-18-91 GJF ANSI naming.
; 05-10-91 GJF Back to _cdecl, sigh...
; 10-20-94 GJF Made locale sensitive (i.e., now works for all
; single-byte character locales). Made multi-thread
; safe. Also, deleted obsolete _STDCALL_ code.
; 10-27-94 GJF Adapted above change for Win32S.
; 11-12-94 GJF Must avoid volatile regs or save them across function
; calls. Also, fixed bug in reg operand size.
; 07-03-95 CFW Changed offset of _lc_handle[LC_CTYPE], added sanity check
; to crtlib.c to catch changes to win32s.h that modify offset.
; 10-03-95 GJF New locale locking scheme.
; 11-13-95 GJF Made _strcmpi a proc instead of a label.
;
;*******************************************************************************
.xlist
include cruntime.inc
.list
ifdef _MT
; Def and decls necessary to assert the lock for the LC_CTYPE locale category
_SETLOCALE_LOCK EQU 19
extrn _lock:proc
extrn _unlock:proc
endif
; Defs and decl necessary to test for the C locale.
_CLOCALEHANDLE EQU 0
LC_CTYPE EQU 2 * 4
ifndef DLL_FOR_WIN32S
extrn __lc_handle:dword
ifdef _MT
extrn __setlc_active:dword
extrn __unguarded_readlc_active:dword
endif
else
extrn _GetPPD:proc
endif
ifdef DLL_FOR_WIN32S
crt_tolower EQU tolower
else
ifdef _MT
crt_tolower EQU _tolower_lk
else
crt_tolower EQU tolower
endif
endif
extrn crt_tolower:proc
page
;***
;int _stricmp(dst, src), _strcmpi(dst, src) - compare strings, ignore case
;
;Purpose:
; _stricmp/_strcmpi perform a case-insensitive string comparision.
; For differences, upper case letters are mapped to lower case.
; Thus, "abc_" < "ABCD" since "_" < "d".
;
; Algorithm:
;
; int _strcmpi (char * dst, char * src)
; {
; int f,l;
;
; do {
; f = tolower(*dst);
; l = tolower(*src);
; dst++;
; src++;
; } while (f && f == l);
;
; return(f - l);
; }
;
;Entry:
; char *dst, *src - strings to compare
;
;Exit:
; AX = -1 if dst < src
; AX = 0 if dst = src
; AX = +1 if dst > src
;
;Uses:
; CX, DX
;
;Exceptions:
;
;*******************************************************************************
CODESEG
public _strcmpi ; alternate entry point for compatibility
_strcmpi proc
_strcmpi endp
public _stricmp
_stricmp proc \
uses edi esi ebx, \
dst:ptr, \
src:ptr
.FPO ( 0, 2, 0, 3, 0, 0 )
; load up args
mov esi,[src] ; esi = src
mov edi,[dst] ; edi = dst
; test locale
ifndef DLL_FOR_WIN32S
lea eax,__lc_handle
cmp [eax + LC_CTYPE],_CLOCALEHANDLE
else
; the following was obtained by compiling stricmp.c and inspecting the
; code listing.
call _GetPPD
;
; IMPORTANT NOTE:
; stricmp.asm, strnicmp.asm, and memicmp.asm hard-code the offset
; of the _lc_handle[2] field within the _CRTDLLPPD structure.
;
; This field MUST be first in the _CRTDLLPPD structure (win32s.h).
;
; Otherwise a debug assertion at Win32s DLL startup will be triggered (crtlib.c).
;
cmp dword ptr [eax + 8],0
endif
jne notclocale
; C locale
mov al,-1 ; fall into loop
align 4
chk_null:
or al,al
jz short done
mov al,[esi] ; al = next source byte
inc esi
mov ah,[edi] ; ah = next dest byte
inc edi
cmp ah,al ; first try case-sensitive comparision
je short chk_null ; match
sub al,'A'
cmp al,'Z'-'A'+1
sbb cl,cl
and cl,'a'-'A'
add al,cl
add al,'A' ; tolower(*dst)
xchg ah,al ; operations on AL are shorter than AH
sub al,'A'
cmp al,'Z'-'A'+1
sbb cl,cl
and cl,'a'-'A'
add al,cl
add al,'A' ; tolower(*src)
cmp al,ah ; inverse of above comparison -- AL & AH are swapped
je short chk_null
; dst < src dst > src
sbb al,al ; AL=-1, CY=1 AL=0, CY=0
sbb al,-1 ; AL=-1 AL=1
done:
movsx eax,al ; extend al to eax
jmp short doret
notclocale:
; Not the C locale. Must call tolower/_tolower_lk to convert chars
; to lower case.
ifndef DLL_FOR_WIN32S
ifdef _MT
cmp __setlc_active,0 ; is setlocale() is active?
jg short do_lock ; yes, go assert lock
inc __unguarded_readlc_active ; no, bump unguarded locale
; read flag
push 0 ; local lock flag is 0
jmp short end_lock
do_lock:
push _SETLOCALE_LOCK
call _lock
mov [esp],1 ; local lock flag is 1
end_lock:
endif
endif
mov eax,255
xor ebx,ebx
align 4
chk_null2:
or al,al ; not that if al == 0, then eax == 0!
jz short done2
mov al,[esi] ; al = next src byte
inc esi
mov bl,[edi] ; bl = next dst byte
inc edi
cmp al,bl ; first try case-sensitive comparision
je short chk_null2 ; match
push eax
push ebx
call crt_tolower ; convert dst char to lower case
mov ebx,eax
add esp,4
call crt_tolower ; convert src char to lower case
add esp,4
cmp bl,al
je chk_null2
sbb eax,eax
sbb eax,-1
done2:
ifndef DLL_FOR_WIN32S
ifdef _MT
mov ebx,eax ; save return value in ebx
pop eax ; get local lock flag
or eax,eax ; lock held?
jnz do_unlock ; yes
dec __unguarded_readlc_active
jmp short end_unlock
do_unlock:
push _SETLOCALE_LOCK
call _unlock
add esp,4
end_unlock:
mov eax,ebx ; recover return value
endif
endif
doret:
ret
_stricmp endp
end