lexcmp.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 95 行

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*
*                            Open Watcom Project
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*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
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*    This file contains Original Code and/or Modifications of Original
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//
// LEXCMP    : compare 2 strings
//

#include "ftnstd.h"
#include "rtenv.h"


static  int     ChkBlanks( char PGM *ptr, uint len ) {
//====================================================

    for(;;) {
        --len;
        if( len == 0 ) break;
        if( *ptr != ' ' ) break;
        ++ptr;
    }
    return( *ptr - ' ' );
}


int     LexStrCmp( char PGM *ptr1, uint len1, char PGM *ptr2, uint len2 ) {
//=========================================================================

// Compare two strings (compile-time entry point).

    int         result;

    for(;;) {
        if( *ptr1 != *ptr2 ) break;
        ++ptr1;
        ++ptr2;
        --len1;
        --len2;
        if( len1 == 0 ) break;
        if( len2 == 0 ) break;
    }
    if( len1 == 0 ) {
        if( len2 == 0 ) return( 0 );
        result = -ChkBlanks( ptr2, len2 );
    } else if( len2 == 0 ) {
        result = ChkBlanks( ptr1, len1 );
    } else {
        result = *ptr1;
        result -= *ptr2;
    }
    if( result < 0 ) {
        result = -1;
    } else if( result > 0 ) {
        result = 1;
    }
    return( result );
}


int     LexCmp( string PGM *str1, string PGM *str2 ) {
//====================================================

// Compare two strings (run-time entry point).

    return( LexStrCmp( str1->strptr, str1->len, str2->strptr, str2->len ) );
}