windows-nt/Source/XPSP1/NT/base/crts/crtw32/mbstring/mbsnccnt.c

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2020-09-26 03:20:57 -05:00
/***
*mbsnccnt.c - Return char count of MBCS string
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Return char count of MBCS string
*
*Revision History:
* 11-19-92 KRS Ported from 16-bit sources.
* 10-05-93 GJF Replaced _CRTAPI1 with __cdecl.
* 04-15-93 CFW Add _MB_CP_LOCK.
* 05-19-94 CFW Enable non-Win32.
* 04-15-98 GJF Revised multithread support based on threadmbcinfo
* structs
*
*******************************************************************************/
#ifdef _MBCS
#include <mtdll.h>
#include <cruntime.h>
#include <mbdata.h>
#include <mbctype.h>
#include <mbstring.h>
/***
* _mbsnccnt - Return char count of MBCS string
*
*Purpose:
* Returns the number of chars between the start of the supplied
* string and the byte count supplied. That is, this routine
* indicates how many chars are in the first "bcnt" bytes
* of the string.
*
*Entry:
* const unsigned char *string = pointer to string
* unsigned int bcnt = number of bytes to scan
*
*Exit:
* Returns number of chars between string and bcnt.
*
* If the end of the string is encountered before bcnt chars were
* scanned, then the length of the string in chars is returned.
*
*Exceptions:
*
*******************************************************************************/
size_t __cdecl _mbsnccnt(
const unsigned char *string,
size_t bcnt
)
{
unsigned int n;
#ifdef _MT
pthreadmbcinfo ptmbci = _getptd()->ptmbcinfo;
if ( ptmbci != __ptmbcinfo )
ptmbci = __updatetmbcinfo();
#endif
for (n = 0; (bcnt-- && *string); n++, string++) {
#ifdef _MT
if ( __ismbblead_mt(ptmbci, *string) ) {
#else
if ( _ismbblead(*string) ) {
#endif
if ( (!bcnt--) || (*++string == '\0'))
break;
}
}
return(n);
}
#endif /* _MBCS */