windows-nt/Source/XPSP1/NT/base/crts/crtw32/misc/w_cmp.c
2020-09-26 16:20:57 +08:00

297 lines
10 KiB
C

/***
*w_cmp.c - W versions of CompareString.
*
* Copyright (c) 1993-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Use either CompareStringA or CompareStringW depending on which is
* available
*
*Revision History:
* 09-14-93 CFW Module created.
* 09-17-93 CFW Use unsigned chars.
* 09-23-93 CFW Correct NLS API params and comments about same.
* 10-07-93 CFW Optimize WideCharToMultiByte, use NULL default char.
* 10-22-93 CFW Test for invalid MB chars using global preset flag.
* 11-09-93 CFW Allow user to pass in code page.
* 11-18-93 CFW Test for entry point function stubs.
* 02-23-94 CFW Use W flavor whenever possible.
* 03-31-94 CFW Include awint.h.
* 05-09-94 CFW Do not let CompareString compare past NULL.
* 06-03-94 CFW Test for empty string early.
* 11/01-94 CFW But not too early for MB strings.
* 12-21-94 CFW Remove invalid MB chars NT 3.1 hack.
* 12-27-94 CFW Call direct, all OS's have stubs.
* 01-10-95 CFW Debug CRT allocs.
* 02-06-95 CFW assert -> _ASSERTE.
* 02-15-97 RDK For narrow comparsion, try W version first so Windows NT
* can process nonANSI codepage correctly.
* 05-15-97 GJF Split off from aw_cmp.c. Replaced use of _malloc_crt
* and _free_crt with _alloca. Also, detab-ed and cleaned
* up the code a bit.
* 05-27-98 GJF Changed wcsncnt() so that it will never examine the
* (cnt + 1)-th byte of the string.
* 08-18-98 GJF Use _malloc_crt if _alloca fails.
* 04-28-99 GJF Changed dwFlags arg value to 0 in WideCharToMultiByte
* calls to avoid problems with codepage 1258 on NT 5.0.
* 12-10-99 GB Added support for recovery from stack overflow around
* _alloca().
* 05-17-00 GB Use ERROR_CALL_NOT_IMPLEMENTED for existance of W API
* 08-23-00 GB Fixed bug with non Ansi CP on Win9x.
*
*******************************************************************************/
#include <cruntime.h>
#include <internal.h>
#include <dbgint.h>
#include <stdlib.h>
#include <setlocal.h>
#include <locale.h>
#include <awint.h>
#include <dbgint.h>
#include <malloc.h>
#define USE_W 1
#define USE_A 2
/***
*int __cdecl wcsncnt - count wide characters in a string, up to n.
*
*Purpose:
* Internal local support function. Counts characters in string before NULL.
* If NULL not found in n chars, then return n.
*
*Entry:
* const wchar_t *string - start of string
* int n - byte count
*
*Exit:
* returns number of wide characaters from start of string to
* NULL (exclusive), up to n.
*
*Exceptions:
*
*******************************************************************************/
static int __cdecl wcsncnt (
const wchar_t *string,
int cnt
)
{
int n = cnt;
wchar_t *cp = (wchar_t *)string;
while (n-- && *cp)
cp++;
return cnt - n - 1;
}
/***
*int __cdecl __crtCompareStringW - Get type information about a wide string.
*
*Purpose:
* Internal support function. Assumes info in wide string format. Tries
* to use NLS API call CompareStringW if available and uses CompareStringA
* if it must. If neither are available it fails and returns 0.
*
*Entry:
* LCID Locale - locale context for the comparison.
* DWORD dwCmpFlags - see NT\Chicago docs
* LPCWSTR lpStringn - wide string to be compared
* int cchCountn - wide char (word) count (NOT including NULL)
* (-1 if NULL terminated)
* int code_page - for MB/WC conversion. If 0, use __lc_codepage
*
*Exit:
* Success: 1 - if lpString1 < lpString2
* 2 - if lpString1 == lpString2
* 3 - if lpString1 > lpString2
* Failure: 0
*
*Exceptions:
*
*******************************************************************************/
int __cdecl __crtCompareStringW(
LCID Locale,
DWORD dwCmpFlags,
LPCWSTR lpString1,
int cchCount1,
LPCWSTR lpString2,
int cchCount2,
int code_page
)
{
static int f_use = 0;
/*
* Look for unstubbed 'preferred' flavor. Otherwise use available flavor.
* Must actually call the function to ensure it's not a stub.
*/
if (0 == f_use)
{
if (0 != CompareStringW(0, 0, L"\0", 1, L"\0", 1))
f_use = USE_W;
else if (GetLastError() == ERROR_CALL_NOT_IMPLEMENTED)
f_use = USE_A;
}
/*
* CompareString will compare past NULL. Must find NULL if in string
* before cchCountn wide characters.
*/
if (cchCount1 > 0)
cchCount1= wcsncnt(lpString1, cchCount1);
if (cchCount2 > 0)
cchCount2= wcsncnt(lpString2, cchCount2);
if (!cchCount1 || !cchCount2)
return (cchCount1 - cchCount2 == 0) ? 2 :
(cchCount1 - cchCount2 < 0) ? 1 : 3;
/* Use "W" version */
if (USE_W == f_use)
{
return CompareStringW( Locale,
dwCmpFlags,
lpString1,
cchCount1,
lpString2,
cchCount2 );
}
/* Use "A" version */
if (USE_A == f_use || f_use == 0)
{
int buff_size1;
int buff_size2;
unsigned char *buffer1;
unsigned char *buffer2;
int retcode = 0;
int malloc_flag1 = 0;
int malloc_flag2 = 0;
int AnsiCP;
/*
* Use __lc_codepage for conversion if code_page not specified
*/
if (0 == Locale)
Locale = __lc_handle[LC_CTYPE];
if (0 == code_page)
code_page = __lc_codepage;
/*
* Always use Ansi codepage with Ansi WinAPI because they use
* Ansi codepage
*/
if ( code_page != (AnsiCP = __ansicp(Locale)))
{
if (AnsiCP != -1)
code_page = AnsiCP;
}
/*
* Convert strings and return the requested information.
*/
/* find out how big a buffer we need (includes NULL if any) */
if ( 0 == (buff_size1 = WideCharToMultiByte( code_page,
0,
lpString1,
cchCount1,
NULL,
0,
NULL,
NULL )) )
return 0;
/* allocate enough space for chars */
__try {
buffer1 = (unsigned char *)_alloca( buff_size1 * sizeof(char) );
}
__except( EXCEPTION_EXECUTE_HANDLER ) {
_resetstkoflw();
buffer1 = NULL;
}
if ( buffer1 == NULL ) {
if ( (buffer1 = (unsigned char *)_malloc_crt(buff_size1 * sizeof(char)))
== NULL )
return 0;
malloc_flag1++;
}
/* do the conversion */
if ( 0 == WideCharToMultiByte( code_page,
0,
lpString1,
cchCount1,
buffer1,
buff_size1,
NULL,
NULL ) )
goto error_cleanup;
/* find out how big a buffer we need (includes NULL if any) */
if ( 0 == (buff_size2 = WideCharToMultiByte( code_page,
0,
lpString2,
cchCount2,
NULL,
0,
NULL,
NULL )) )
goto error_cleanup;
/* allocate enough space for chars */
__try {
buffer2 = (unsigned char *)_alloca( buff_size2 * sizeof(char) );
}
__except( EXCEPTION_EXECUTE_HANDLER ) {
_resetstkoflw();
buffer2 = NULL;
}
if ( buffer2 == NULL ) {
if ( (buffer2 = (unsigned char *)_malloc_crt(buff_size2 * sizeof(char)))
== NULL )
goto error_cleanup;
malloc_flag2++;
}
/* do the conversion */
if ( 0 != WideCharToMultiByte( code_page,
0,
lpString2,
cchCount2,
buffer2,
buff_size2,
NULL,
NULL ) )
retcode = CompareStringA( Locale,
dwCmpFlags,
buffer1,
buff_size1,
buffer2,
buff_size2 );
if ( malloc_flag2 )
_free_crt(buffer2);
error_cleanup:
if ( malloc_flag1 )
_free_crt(buffer1);
return retcode;
}
else /* f_use is neither USE_A nor USE_W */
return 0;
}