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

90 lines
2.3 KiB
C

/***
*ismbstrail.c - True _ismbstrail function
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Contains the function _ismbstrail, which is a true context-sensitive
* MBCS trail-byte function. While much less efficient than _ismbbtrail,
* it is also much more sophisticated, in that it determines whether a
* given sub-string pointer points to a trail byte or not, taking into
* account the context in the string.
*
*Revision History:
*
* 08-03-93 KRS Ported from 16-bit tree.
* 10-05-93 GJF Replaced _CRTAPI1 with __cdecl.
* 04-15-93 CFW Add _MB_CP_LOCK.
* 05-09-94 CFW Optimize for SBCS.
* 05-19-94 CFW Enable non-Win32.
* 09-11-97 GJF Replaced __mbcodepage == 0 with _ISNOTMBCP.
* 04-02-98 GJF Implemented multithread support based on threadmbcinfo
* structs
*
*******************************************************************************/
#ifdef _MBCS
#include <mtdll.h>
#include <cruntime.h>
#include <stddef.h>
#include <mbdata.h>
#include <mbctype.h>
#include <mbstring.h>
/***
* int _ismbstrail(const unsigned char *string, const unsigned char *current);
*
*Purpose:
*
* _ismbstrail - Check, in context, for MBCS trail byte
*
*Entry:
* unsigned char *string - ptr to start of string or previous known lead byte
* unsigned char *current - ptr to position in string to be tested
*
*Exit:
* TRUE : -1
* FALSE : 0
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _ismbstrail(
const unsigned char *string,
const unsigned char *current
)
{
#ifdef _MT
pthreadmbcinfo ptmbci = _getptd()->ptmbcinfo;
if ( ptmbci != __ptmbcinfo )
ptmbci = __updatetmbcinfo();
if ( _ISNOTMBCP_MT(ptmbci) )
#else
if ( _ISNOTMBCP )
#endif
return 0;
while ( string <= current && *string ) {
#ifdef _MT
if ( __ismbblead_mt(ptmbci, (*string)) ) {
#else
if ( _ismbblead((*string)) ) {
#endif
if (++string == current) /* check trail byte */
return -1;
if (!(*string))
return 0;
}
++string;
}
return 0;
}
#endif