caseless-str.h

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////////////////////////////////////////////////////////////////////////
//
// Copyright (C) 2007-2021 The Octave Project Developers
//
// See the file COPYRIGHT.md in the top-level directory of this
// distribution or <https://octave.org/copyright/>.
//
// This file is part of Octave.
//
// Octave 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 3 of the License, or
// (at your option) any later version.
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// 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.
//
// You should have received a copy of the GNU General Public License
// along with Octave; see the file COPYING.  If not, see
// <https://www.gnu.org/licenses/>.
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////////////////////////////////////////////////////////////////////////
 
#if ! defined (octave_caseless_str_h)
#define octave_caseless_str_h 1
 
#include "octave-config.h"
 
#include <cctype>
#include <string>
 
class caseless_str : public std::string
{
public:
 
  typedef std::string::iterator iterator;
  typedef std::string::const_iterator const_iterator;
 
  caseless_str (void) = default;
 
  caseless_str (const std::string& s) : std::string (s) { }
  caseless_str (const char *s) : std::string (s) { }
 
  caseless_str (const caseless_str&) = default;
 
  caseless_str& operator = (const caseless_str&) = default;
 
  ~caseless_str (void) = default;
 
  bool operator < (const std::string& s) const
  {
    auto p1 = begin ();
    auto p2 = s.begin ();
 
    while (p1 != end () && p2 != s.end ())
      {
        char lp1 = std::tolower (*p1);
        char lp2 = std::tolower (*p2);
 
        if (lp1 > lp2)
          return false;
        if (lp1 < lp2)
          return true;
 
        p1++;
        p2++;
      }
 
    if (length () >= s.length ())
      return false;
    else
      return true;
  }
 
  // Case-insensitive comparison.
  bool compare (const std::string& s, size_t limit = std::string::npos) const
  {
    auto p1 = begin ();
    auto p2 = s.begin ();
 
    size_t k = 0;
 
    while (p1 != end () && p2 != s.end () && k++ < limit)
      {
        if (std::tolower (*p1) != std::tolower (*p2))
          return false;
 
        p1++;
        p2++;
      }
 
    return (limit == std::string::npos) ? size () == s.size () : k == limit;
  }
};
 
#endif