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

114 lines
3.3 KiB
C

/***
*mbsnbset.c - Sets first n bytes of string to given character (MBCS)
*
* Copyright (c) 1985-2001, Microsoft Corporation. All rights reserved.
*
*Purpose:
* Sets first n bytes of string to given character (MBCS)
*
*Revision History:
* 08-03-93 KRS Ported from 16-bit sources.
* 08-20-93 CFW Change short params to int for 32-bit tree.
* 10-05-93 GJF Replaced _CRTAPI1 with __cdecl.
* 04-15-93 CFW Fix history.
* 05-09-94 CFW Optimize for SBCS.
* 09-11-97 GJF Replaced __mbcodepage == 0 with _ISNOTMBCP.
*
*******************************************************************************/
#ifdef _MBCS
#include <cruntime.h>
#include <string.h>
#include <mbdata.h>
#include <mbctype.h>
#include <mbstring.h>
/***
* _mbsnbset - Sets first n bytes of string to given character (MBCS)
*
*Purpose:
* Sets the first n bytes of string to the supplied
* character value. If the length of string is less than n,
* the length of string is used in place of n. Handles
* MBCS chars correctly.
*
* There are several factors that make this routine complicated:
* (1) The fill value may be 1 or 2 bytes long.
* (2) The fill operation may end by hitting the count value
* or by hitting the end of the string.
* (3) A null terminating char is NOT placed at the end of
* the string.
*
* Cases to be careful of (both of these can occur at once):
* (1) Leaving an "orphaned" trail byte in the string (e.g.,
* overwriting a lead byte but not the corresponding trail byte).
* (2) Writing only the 1st byte of a 2-byte fill value because the
* end of string was encountered.
*
*Entry:
* unsigned char *string = string to modify
* unsigned int val = value to fill string with
* size_t count = count of characters to fill
*
*
*Exit:
* Returns string = now filled with char val
*
*Uses:
*
*Exceptions:
*
*******************************************************************************/
unsigned char * __cdecl _mbsnbset(
unsigned char *string,
unsigned int val,
size_t count
)
{
unsigned char *start = string;
unsigned char highval, lowval;
if ( _ISNOTMBCP )
return _strnset(string, val, count);
/*
* leadbyte flag indicates if the last byte we overwrote was
* a lead byte or not.
*/
if (highval = (unsigned char)(val>>8)) {
/* double byte value */
lowval = (unsigned char)(val & 0x00ff);
while ((count--) && *string) {
/* pad with ' ' if no room for both bytes -- odd len */
if ((!count--) || (!*(string+1))) {
*string = ' ';
break;
}
*string++ = highval;
*string++ = lowval;
}
}
else {
/* single byte value */
while (count-- && *string) {
*string++ = (unsigned char)val;
}
}
return( start );
}
#endif /* _MBCS */