windows-nt/Source/XPSP1/NT/com/ole32/common/cruntime/chicago/wcslwr.c
2020-09-26 16:20:57 +08:00

99 lines
2.5 KiB
C

/***
*wcslwr.c - routine to map upper-case characters in a wchar_t string
* to lower-case
*
* Copyright (c) 1985-1992, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Converts all the upper case characters in a wchar_t string
* to lower case, in place.
*
*Revision History:
* 09-09-91 ETC Created from strlwr.c.
* 04-06-92 KRS Make work without _INTL also.
* 08-19-92 KRS Activate NLS support.
* 08-22-92 SRW Allow INTL definition to be conditional for building ntcrt.lib
* 09-02-92 SRW Get _INTL definition via ..\crt32.def
* 06-02-93 SRW ignore _INTL if _NTSUBSET_ defined.
*
*******************************************************************************/
#include <windows.h>
#include <cruntime.h>
/***
*wchar_t *_wcslwr(string) - map upper-case characters in a string to lower-case
*
*Purpose:
* wcslwr converts upper-case characters in a null-terminated wchar_t
* string to their lower-case equivalents. The result may be longer or
* shorter than the original string. Assumes enough space in string
* to hold the result.
*
*Entry:
* wchar_t *wsrc - wchar_t string to change to lower case
*
*Exit:
* input string address
*
*Exceptions:
* on an error, the original string is unaltered
*
*******************************************************************************/
wchar_t * _CALLTYPE1 _wcslwr (
wchar_t * wsrc
)
{
wchar_t * p;
// Prescan the buffer. If all this is in the first 128 characters, it's just
// ANSII, and we can do it ourselves...
for (p = wsrc; *p; p++)
{
if (*p < 128)
{
*p = (wchar_t)CharLowerA((LPSTR)*p);
}
else
{
// We can't handle this character in place, so convert the remainder of the string
// to MBS, lower-case it, and convert it back to Unicode.
int wLength = lstrlenW (p);
int mbsLength;
CHAR * mbsBuffer = (CHAR *)LocalAlloc (LMEM_FIXED, 2 * sizeof (CHAR) * wLength + 1);
if (mbsBuffer == NULL)
{
return NULL;
}
mbsLength = WideCharToMultiByte (CP_ACP,
WC_COMPOSITECHECK,
p,
wLength,
mbsBuffer,
2 * sizeof (CHAR) * wLength,
NULL,
NULL);
if (mbsLength == 0)
{
// We don't know what happened, but it wasn't good
return NULL;
}
mbsBuffer[mbsLength] = '\0';
CharLowerA (mbsBuffer);
if (MultiByteToWideChar (CP_ACP, MB_PRECOMPOSED, mbsBuffer, mbsLength, p, wLength) == 0)
{
return NULL;
}
break;
}
}
return wsrc;
}