fstrspn.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 56 行

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*                            Open Watcom Project
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#include "variety.h"
#include <string.h>
#include "setbits.h"

/*  The strspn function computes the length of the initial segment of the
    string pointed to by str which consists entirely of characters from
    the string pointed to by charset.
*/

_WCRTLINK size_t _fstrspn( const char _WCFAR *str, const char _WCFAR *charset )
{
    unsigned /*char*/ tc;
    unsigned char vector[32];
    size_t len;

    __fsetbits( vector, charset );
    len = 0;
    for( ; tc = (unsigned char) *str; ++str, ++len ) {
        /* quit if we find any char not in charset */
        if( ( vector[ tc >> 3 ] & _Bits[ tc & 0x07 ] ) == 0 )  break;
    }
    return( len );
}