rstrchr.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 270 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"


#ifdef __WIDECHAR__
 wchar_t *wcschr( const wchar_t *s, wint_t c )
#else
 char *strchr( const char *s, int c )
#endif
/********************************************/
{
#if USE_INT64
    RISC_DATA_LOCALREF;
#endif
    UINT *              dw = ROUND(s);          /* round down to dword */
    UINT                dword, cdword, tmpdword;
    INT                 len = 0;
    int                 offset = OFFSET(s);
#ifdef __WIDECHAR__
    UINT                cShl16;
#else
    INT                 cShl8, cShl16, cShl24;
#if USE_INT64
    INT                 cShl32, cShl40, cShl48, cShl56;
#endif
#endif

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

    /*** Initialize locals ***/
    c &= CHR1MASK;
    #ifdef __WIDECHAR__
        cShl16 = c << 16;
        cdword = cShl16 | c;
    #else
        cShl8 = c << 8;
        cShl16 = c << 16;
        cShl24 = c << 24;
        #if USE_INT64
            cShl32 = (UINT)c << 32;
            cShl40 = (UINT)c << 40;
            cShl48 = (UINT)c << 48;
            cShl56 = (UINT)c << 56;
            cdword = cShl56 | cShl48 | cShl40 | cShl32 | cShl24 | cShl16 | cShl8 | c;
        #else
            cdword = cShl24 | cShl16 | cShl8 | c;
        #endif
    #endif

    /*** Scan any bytes up to a 4-byte alignment ***/
    if( offset != 0 ) {
        dword = *dw++;
        #ifdef __WIDECHAR__
            tmpdword = CHR2(dword);
            if( tmpdword == cShl16 ) {
                return( (CHAR_TYPE*)s+len );
            } else if( tmpdword == 0 ) {
                return( NULL );
            }
            len++;
        #else
            switch( offset ) {
              case 1:
                tmpdword = CHR2(dword);
                if( tmpdword == cShl8 ) {
                    return( (CHAR_TYPE*)s+len );
                } else if( tmpdword == 0 ) {
                    return( NULL );
                }
                len++;
                /* fall through */
              case 2:
                tmpdword = CHR3(dword);
                if( tmpdword == cShl16 ) {
                    return( (CHAR_TYPE*)s+len );
                } else if( tmpdword == 0 ) {
                    return( NULL );
                }
                len++;
                /* fall through */
            #if USE_INT64
              case 3:
                tmpdword = CHR4(dword);
                if( tmpdword == cShl24 ) {
                    return( (CHAR_TYPE*)s+len );
                } else if( tmpdword == 0 ) {
                    return( NULL );
                }
                len++;
                /* fall through */
              case 4:
                tmpdword = CHR5(dword);
                if( tmpdword == cShl32 ) {
                    return( (CHAR_TYPE*)s+len );
                } else if( tmpdword == 0 ) {
                    return( NULL );
                }
                len++;
                /* fall through */
              case 5:
                tmpdword = CHR6(dword);
                if( tmpdword == cShl40 ) {
                    return( (CHAR_TYPE*)s+len );
                } else if( tmpdword == 0 ) {
                    return( NULL );
                }
                len++;
                /* fall through */
              case 6:
                tmpdword = CHR7(dword);
                if( tmpdword == cShl48 ) {
                    return( (CHAR_TYPE*)s+len );
                } else if( tmpdword == 0 ) {
                    return( NULL );
                }
                len++;
                /* fall through */
              default:
                tmpdword = CHR8(dword);
                if( tmpdword == cShl56 ) {
                    return( (CHAR_TYPE*)s+len );
                } else if( tmpdword == 0 ) {
                    return( NULL );
                }
                len++;
            #else
              default:
                tmpdword = CHR4(dword);
                if( tmpdword == cShl24 ) {
                    return( (CHAR_TYPE*)s+len );
                } else if( tmpdword == 0 ) {
                    return( NULL );
                }
                len++;
            #endif
            }
        #endif
    }

    /*** Scan in aligned 4-byte groups ***/
    for( ;; ) {
        dword = *dw++;
        if( GOT_NIL(dword) )  break;
        tmpdword = dword ^ cdword;
        if( GOT_NIL(tmpdword) ) {
            #ifdef __WIDECHAR__
                if( !CHR1(tmpdword) )  return( (CHAR_TYPE*)s+len );
                /* otherwise */        return( (CHAR_TYPE*)s+len+1 );
            #else
                if( !CHR1(tmpdword) )  return( (char*)s+len );
                if( !CHR2(tmpdword) )  return( (char*)s+len+1 );
                if( !CHR3(tmpdword) )  return( (char*)s+len+2 );
                if( !CHR4(tmpdword) )  return( (char*)s+len+3 );
                #if USE_INT64
                    if( !CHR5(tmpdword) )  return( (char*)s+len+4 );
                    if( !CHR6(tmpdword) )  return( (char*)s+len+5 );
                    if( !CHR7(tmpdword) )  return( (char*)s+len+6 );
                    if( !CHR8(tmpdword) )  return( (char*)s+len+7 );
                #endif
            #endif
        }
        len += CHARS_PER_WORD;
    }

    /*** Scan the last byte(s) in the string ***/
    tmpdword = CHR1(dword);
    if( tmpdword == c ) {
        return( (CHAR_TYPE*)s+len );
    } else if( tmpdword == 0 ) {
        return( NULL );
    }

    #ifdef __WIDECHAR__
        tmpdword = CHR2(dword);
        if( tmpdword == cShl16 ) {
            return( (CHAR_TYPE*)s+len+1 );
        } else if( tmpdword == 0 ) {
            return( NULL );
        }
    #else
        tmpdword = CHR2(dword);
        if( tmpdword == cShl8 ) {
            return( (CHAR_TYPE*)s+len+1 );
        } else if( tmpdword == 0 ) {
            return( NULL );
        }

        tmpdword = CHR3(dword);
        if( tmpdword == cShl16 ) {
            return( (CHAR_TYPE*)s+len+2 );
        } else if( tmpdword == 0 ) {
            return( NULL );
        }

        tmpdword = CHR4(dword);
        if( tmpdword == cShl24 ) {
            return( (CHAR_TYPE*)s+len+3 );
        } else if( tmpdword == 0 ) {
            return( NULL );
        }

        #if USE_INT64
            tmpdword = CHR5(dword);
            if( tmpdword == cShl32 ) {
                return( (CHAR_TYPE*)s+len+4 );
            } else if( tmpdword == 0 ) {
                return( NULL );
            }

            tmpdword = CHR6(dword);
            if( tmpdword == cShl40 ) {
                return( (CHAR_TYPE*)s+len+5 );
            } else if( tmpdword == 0 ) {
                return( NULL );
            }

            tmpdword = CHR7(dword);
            if( tmpdword == cShl48 ) {
                return( (CHAR_TYPE*)s+len+6 );
            } else if( tmpdword == 0 ) {
                return( NULL );
            }

            tmpdword = CHR8(dword);
            if( tmpdword == cShl48 ) {
                return( (CHAR_TYPE*)s+len+7 );
            } else if( tmpdword == 0 ) {
                return( NULL );
            }
        #endif
    #endif

    return( NULL );
}