regex.cpp

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/* Copyright (c) 2010 Wildfire Games
 *
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 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// minimal regex implementation

#include "precompiled.h"


int match_wildcard(const wchar_t* s, const wchar_t* w)
{
    if(!w)
        return 1;

    // saved position in both strings, used to expand '*':
    // s2 is advanced until match.
    // initially 0 - we abort on mismatch before the first '*'.
    const wchar_t* s2 = 0;
    const wchar_t* w2 = 0;

    while(*s)
    {
        const wchar_t wc = *w;
        if(wc == '*')
        {
            // wildcard string ended with * => match.
            if(*++w == '\0')
                return 1;

            w2 = w;
            s2 = s+1;
        }
        // match one character
        else if(towupper(wc) == towupper(*s) || wc == '?')
        {
            w++;
            s++;
        }
        // mismatched character
        else
        {
            // no '*' found yet => mismatch.
            if(!s2)
                return 0;

            // resume at previous position+1
            w = w2;
            s = s2++;
        }
    }

    // strip trailing * in wildcard string
    while(*w == '*')
        w++;

    return (*w == '\0');
}