rstrnset.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 180 行

/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
*    Public License version 1.0 (the 'License'). You may not use this file
*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
*    ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
*    provided with the Original Code and Modifications, and is also
*    available at www.sybase.com/developer/opensource.
*
*    The Original Code and all software distributed under the License are
*    distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
*    EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
*    ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
*    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
*    NON-INFRINGEMENT. Please see the License for the specific language
*    governing rights and limitations under the License.
*
*  ========================================================================
*
* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
*               DESCRIBE IT HERE!
*
****************************************************************************/


#include "widechar.h"
#include <string.h>
#include "riscstr.h"


CHAR_TYPE *__F_NAME(strnset,_wcsnset)( CHAR_TYPE *s, int c, size_t n )
/********************************************************************/
{
    RISC_DATA_LOCALREF;
    UINT *           dw = ROUND(s); /* round down to dword */
    UINT             dword, cdword, tmpdword;
    INT              offset = OFFSET(s);

    #ifdef __WIDECHAR__
        if( offset % 2 )  return( __simple__wcsnset( s, c, n ) );
    #endif

    if( n == 0 )  return( s ); // nothing left to set

    /*** Initialize locals ***/
    c &= CHR1MASK;
    #ifdef __WIDECHAR__
        cdword = (c<<16) | c;
    #else
        cdword = (c<<24) | (c<<16) | (c<<8) | c;
    #endif
    dword = *dw;

    /*** Set any bytes up to a 4-byte alignment ***/
    tmpdword = FRONT_CHRS(dword,offset);
    #ifdef __WIDECHAR__
        switch( offset ) {
          case 0:
            if( CHR1(dword) && n ) {
                tmpdword |= CHR1(cdword);
                --n;
            } else {
                return( s );
            }
            /* fall through */
          default:              /* offset must equal 2 (no odd offsets) */
            if( CHR2(dword) && n ) {
                tmpdword |= CHR2(cdword);
                *dw = tmpdword;
                --n;
            } else {
                tmpdword |= SKIP_CHRS(dword,1);
                *dw = tmpdword;
                return( s );
            }
        }
    #else
        switch( offset ) {
          case 0:
            if( CHR1(dword) && n ) {
                tmpdword |= CHR1(cdword);
                --n;
            } else {
                return( s );
            }
            /* fall through */
          case 1:
            if( CHR2(dword) && n ) {
                tmpdword |= CHR2(cdword);
                --n;
            } else {
                tmpdword |= SKIP_CHRS(dword,1);
                *dw = tmpdword;
                return( s );
            }
          case 2:
            if( CHR3(dword) && n ) {
                tmpdword |= CHR3(cdword);
                --n;
            } else {
                tmpdword |= SKIP_CHRS(dword,2);
                *dw = tmpdword;
                return( s );
            }
          default:
            if( CHR4(dword) && n ) {
                tmpdword |= CHR4(cdword);
                *dw = tmpdword;
                --n;
            } else {
                tmpdword |= SKIP_CHRS(dword,3);
                *dw = tmpdword;
                return( s );
            }
        }
    #endif

    dw++;

    /*** Write in aligned 4-byte groups ***/
    for( ;; ) {
        if( n == 0 )  return( s ); // nothing left to set
        dword = *dw;
        if( GOT_NIL(dword) )  break;
        if( n >= CHARS_PER_WORD ) {
            *dw++ = cdword;
            n -= CHARS_PER_WORD;
        } else {
            *dw = FRONT_CHRS(cdword,n) | SKIP_CHRS(dword,n);
            return( s );
        }
    }

    /*** Write in last dword ***/
    #ifdef __WIDECHAR__
        if( !CHR1(dword) ) {
            return( s );
        } else {
            if( n >= 2 ) {
                *dw = SKIP_CHRS(dword,2) | FRONT_CHRS(cdword,2);
            } else if( n == 1 ) {
                *dw = SKIP_CHRS(dword,1) | FRONT_CHRS(cdword,1);
            }
            return( s );
        }
    #else
        if( !CHR1(dword) ) {
            return( s );
        } else if( !CHR2(dword) ) {
            if (n>=1) {
                *dw = (SKIP_CHRS(dword,1) | FRONT_CHRS(cdword,1));
            }
            return( s );
        } else if( !CHR3(dword) ) {
            if (n>=2) {
                *dw = (SKIP_CHRS(dword,2) | FRONT_CHRS(cdword,2));
            } else if (n==1) {
                *dw = (SKIP_CHRS(dword,1) | FRONT_CHRS(cdword,1));
            }
            return( s );
        } else {
            if (n>=3) {
                *dw = (SKIP_CHRS(dword,3) | FRONT_CHRS(cdword,3));
            } else if (n==2) {
                *dw = (SKIP_CHRS(dword,2) | FRONT_CHRS(cdword,2));
            } else if (n==1) {
                *dw = (SKIP_CHRS(dword,1) | FRONT_CHRS(cdword,1));
            }
            return( s );
        }
    #endif
}