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

108 lines
2.7 KiB
C

/***
*mbsncmp.c - Compare n characters of two MBCS strings
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Compare n characters of two MBCS strings
*
*Revision History:
* 11-19-92 KRS Ported from 16-bit sources.
* 10-05-93 GJF Replaced _CRTAPI1 with __cdecl.
* 04-12-94 CFW Make function generic.
* 04-15-93 CFW Add _MB_CP_LOCK.
* 04-21-93 CFW Update pointer.
* 05-05-94 CFW Work around NT/Chico bug: CompareString ignores
* control characters.
* 05-09-94 CFW Optimize for SBCS, no re-scan if CompareString fixed.
* 05-12-94 CFW Back to hard-coded, CompareString sort is backwards.
* 05-19-94 CFW Enable non-Win32.
* 09-11-97 GJF Replaced __mbcodepage == 0 with _ISNOTMBCP.
* 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 <string.h>
#include <mbstring.h>
/***
*int mbsncmp(s1, s2, n) - Compare n characters of two MBCS strings
*
*Purpose:
* Compares up to n charcters of two strings for lexical order.
* Strings are compared on a character basis, not a byte basis.
*
*Entry:
* unsigned char *s1, *s2 = strings to compare
* size_t n = maximum number of characters to compare
*
*Exit:
* returns <0 if s1 < s2
* returns 0 if s1 == s2
* returns >0 if s1 > s2
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _mbsncmp(
const unsigned char *s1,
const unsigned char *s2,
size_t n
)
{
unsigned short c1, c2;
#ifdef _MT
pthreadmbcinfo ptmbci = _getptd()->ptmbcinfo;
if ( ptmbci != __ptmbcinfo )
ptmbci = __updatetmbcinfo();
#endif
if (n==0)
return(0);
#ifdef _MT
if ( _ISNOTMBCP_MT(ptmbci) )
#else
if ( _ISNOTMBCP )
#endif
return strncmp(s1, s2, n);
while (n--) {
c1 = *s1++;
#ifdef _MT
if ( __ismbblead_mt(ptmbci, c1) )
#else
if ( _ismbblead(c1) )
#endif
c1 = ( (*s1 == '\0') ? 0 : ((c1<<8) | *s1++) );
c2 = *s2++;
#ifdef _MT
if ( __ismbblead_mt(ptmbci, c2) )
#else
if ( _ismbblead(c2) )
#endif
c2 = ( (*s2 == '\0') ? 0 : ((c2<<8) | *s2++) );
if (c1 != c2)
return( (c1 > c2) ? 1 : -1);
if (c1 == 0)
return(0);
}
return(0);
}
#endif /* _MBCS */