---

more/gen/identifier.h

Go to the documentation of this file.

//  Copyright (C) 2001--2002  Petter Urkedal
//
//  This file 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 file 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.
//
//  You should have received a copy of the GNU General Public License
//  along with this program; if not, write to the Free Software
//  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
//
//  As a special exception, you may use this file as part of a free
//  software library without restriction.  Specifically, if other files
//  instantiate templates or use macros or inline functions from this
//  file, or you compile this file and link it with other files to
//  produce an executable, this file does not by itself cause the
//  resulting executable to be covered by the GNU General Public
//  License.  This exception does not however invalidate any other
//  reasons why the executable file might be covered by the GNU General
//  Public License.
//
//  $Id: identifier.h,v 1.2 2002/08/24 13:58:10 petter_urkedal Exp $


#ifndef MORE_GEN_IDENTIFIER_H
#define MORE_GEN_IDENTIFIER_H

#include <iosfwd>
#include <more/io/fwd.h>
#include <cstring>

namespace more {
namespace gen {

  /** \class identifier identifier.h more/gen/identifier.h
   **
   ** An identifier.  This is just a simple string-like class with
   ** constant-time comparison.  String manipulation is not provided
   ** by intention, as that would lead to generation of redundant
   ** unique string pointers.  Use \c std::string or \c gc_string to
   ** create the string first, if needed. */
  struct identifier
  {
      typedef std::size_t size_type;

      /** Construct an invalid identifier.  Ideally this ctor would
          create an anonymous unique identifier, but that may have
          lead to many redundant allocations declared and defined
          separately. */
      identifier()
          : m_str(0) {}

      /// Construct an object identified by "str".
      identifier(char const* str);

      /** Return a C string which is lexically equal to the string
          this object was constructed from. */
      char const* c_str() const { return m_str; }

      size_type length() const { return m_str? std::strlen(m_str) : 0; }

      /// True iff the identifier is valid.
      bool is_defined() const { return m_str; }

      /// Equivalent to "strcmp(c_str(), rhs.c_str()) == 0", but faster.
      bool operator==(identifier const& rhs) const
      {
          return m_str == rhs.m_str;
      }

      /// True if the identifiers are different.
      bool operator!=(identifier const& rhs) const
      {
          return m_str != rhs.m_str;
      }

      /// Provides an arbitrary ordering if identifiers.
      bool operator<(identifier const& rhs) const
      {
          return m_str < rhs.m_str;
      }

      void sync(io::syncstream&);

      friend std::ostream& operator<<(std::ostream&, identifier const&);

    private:
      char const* m_str;
  };

}}

#endif

---