// -*- related-file-name: "../include/lcdf/globmatch.hh" -*-

/* globmatch.{cc,hh} -- glob_match() function for shell globbing
 *
 * Copyright (c) 2000-2023 Eddie Kohler
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version. This program is distributed in the hope that it will be
 * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
 * Public License for more details.
 */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <lcdf/globmatch.hh>
#include <lcdf/string.hh>
#include <lcdf/vector.hh>

bool
glob_match(const String& str, const String& pattern)
{
    const char* sdata = str.data();
    const char* pdata = pattern.data();
    int slen = str.length();
    int plen = pattern.length();
    int spos = 0, ppos = 0;
    Vector<int> glob_ppos, glob_spos1, glob_spos2;

    while (1) {
        while (ppos < plen)
            switch (pdata[ppos]) {

              case '?':
                if (spos >= slen)
                    goto done;
                spos++;
                ppos++;
                break;

              case '*':
                glob_ppos.push_back(ppos + 1);
                glob_spos1.push_back(spos);
                glob_spos2.push_back(slen);
                spos = slen;
                ppos++;
                break;

              case '[': {
                  if (spos >= slen)
                      goto done;

                  // find end of character class
                  int p = ppos + 1;
                  bool negated = false;
                  if (p < plen && pdata[p] == '^') {
                      negated = true;
                      p++;
                  }
                  int first = p;
                  if (p < plen && pdata[p] == ']')
                      p++;
                  while (p < plen && pdata[p] != ']')
                      p++;
                  if (p >= plen) // not a character class at all
                      goto ordinary;

                  // parse character class
                  bool in = false;
                  for (int i = first; i < p && !in; i++) {
                      int c1 = pdata[i];
                      int c2 = c1;
                      if (i < p - 2 && pdata[i+1] == '-') {
                          c2 = pdata[i+2];
                          i += 2;
                      }
                      if (sdata[spos] >= c1 && sdata[spos] <= c2)
                          in = true;
                  }

                  if ((negated && in) || (!negated && !in))
                      goto done;
                  ppos = p + 1;
                  spos++;
                  break;
              }

              default:
              ordinary:
                if (spos >= slen || sdata[spos] != pdata[ppos])
                    goto done;
                spos++;
                ppos++;
                break;

            }

      done:
        if (spos == slen && ppos == plen)
            return true;
        while (glob_ppos.size() && glob_spos1.back() == glob_spos2.back()) {
            glob_ppos.pop_back();
            glob_spos1.pop_back();
            glob_spos2.pop_back();
        }
        if (glob_ppos.size()) {
            glob_spos2.back()--;
            spos = glob_spos2.back();
            ppos = glob_ppos.back();
        } else
            return false;
    }
}
