Source code of Windows XP (NT5)
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/***
*mbsnbcmp.c - Compare n bytes of two MBCS strings
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Compare n bytes of two MBCS strings
*
*Revision History:
* 08-03-93 KRS Ported from 16-bit sources.
* 10-05-93 GJF Replaced _CRTAPI1 with __cdecl.
* 04-12-94 CFW Make function generic.
* 04-18-94 CFW Don't ignore case.
* 05-05-94 CFW Work around NT/Chico bug: CompareString ignores
* control characters.
* 05-09-94 CFW Return EQUAL when loop exits.
* 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.
* 05-20-94 CFW Bug fix: if last char is LB, must still test values.
* 05-27-94 CFW Last char LB should end string.
* 06-02-94 CFW Fix comments.
* 09-11-97 GJF Replaced __mbcodepage == 0 with _ISNOTMBCP.
* 04-13-98 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 mbsnbcmp(s1, s2, n) - Compare n bytes of two MBCS strings
*
*Purpose:
* Compares up to n bytes of two strings for lexical order.
*
*Entry:
* unsigned char *s1, *s2 = strings to compare
* size_t n = maximum number of bytes to compare
*
*Exit:
* returns <0 if s1 < s2
* returns 0 if s1 == s2
* returns >0 if s1 > s2
*
*Exceptions:
*
*******************************************************************************/
int __cdecl _mbsnbcmp(
const unsigned char *s1,
const unsigned char *s2,
size_t n
)
{
unsigned short c1, c2;
#ifdef _MT
pthreadmbcinfo ptmbci = _getptd()->ptmbcinfo;
#endif
if (n==0)
return(0);
#ifdef _MT
if ( ptmbci != __ptmbcinfo )
ptmbci = __updatetmbcinfo();
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
{
if (n==0)
{
c1 = 0; /* 'naked' lead - end of string */
#ifdef _MT
c2 = __ismbblead_mt(ptmbci, *s2) ? 0 : *s2;
#else
c2 = _ismbblead(*s2) ? 0 : *s2;
#endif
goto test;
}
c1 = ( (*s1 == '\0') ? 0 : ((c1<<8) | *s1++) );
}
c2 = *s2++;
#ifdef _MT
if ( __ismbblead_mt(ptmbci, c2) )
#else
if ( _ismbblead(c2) )
#endif
{
if (n==0)
{
c2 = 0; /* 'naked' lead - end of string */
goto test;
}
--n;
c2 = ( (*s2 == '\0') ? 0 : ((c2<<8) | *s2++) );
}
test:
if (c1 != c2)
return( (c1 > c2) ? 1 : -1);
if (c1 == 0)
return(0);
}
return(0);
}
#endif /* _MBCS */