Ticket #1169: const_string.hpp

#ifndef  CONST_STRING_HPP
#define  CONST_STRING_HPP

#include <string>

// ************************************************************************** //
// **************                 const_string                 ************** //
// ************************************************************************** //

class const_string {
public:
  // Constructors
  const_string()
    : m_begin( "" ), m_end( m_begin ) {}

  const_string( const std::string& s )
    : m_begin( s.c_str() ),
      m_end( m_begin + s.length() ) {}

  const_string( char const* s )
    : m_begin(s), m_end(s + (s?strlen(s):0))
  { if( is_empty()) erase(); } // avoids problems with data() if s == NULL

  const_string( char const* s, size_t length )
    : m_begin( s ), m_end( m_begin + length )
  { if( length == 0 ) erase(); }

  const_string( char const* first, char const* last )
    : m_begin( first ), m_end( last ) {}

  // public members
  char const* data() const     { return m_begin; }
  size_t      length() const   { return m_end - m_begin; }
  bool        is_empty() const { return m_end == m_begin; }
  void        erase()          { m_begin = m_end = ""; }

private:

  // Data members
  char const*     m_begin;
  char const*     m_end;

};

#endif