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// Short-string-optimized versatile string base -*- C++ -*-

// Copyright (C) 2005, 2006 Free Software Foundation, Inc.

//

// This file is part of the GNU ISO C++ Library.  This library 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, or (at your option)

// any later version.

// This library 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 library; see the file COPYING.  If not, write to the Free

// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// 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.

/** @file ext/sso_string_base.h

 *  This file is a GNU extension to the Standard C++ Library.

 *  This is an internal header file, included by other library headers.

 *  You should not attempt to use it directly.

 */

#ifndef _SSO_STRING_BASE_H

#define _SSO_STRING_BASE_H 1

namespace __gnu_cxx

{

  template<typename _CharT, typename _Traits, typename _Alloc>

    class __sso_string_base

    : protected __vstring_utility<_CharT, _Traits, _Alloc>

    {

    public:

      typedef _Traits                                       traits_type;

      typedef typename _Traits::char_type                   value_type;

      typedef __vstring_utility<_CharT, _Traits, _Alloc>    _Util_Base;

      typedef typename _Util_Base::_CharT_alloc_type        _CharT_alloc_type;

      typedef typename _CharT_alloc_type::size_type         size_type;

    private:

      // The maximum number of individual char_type elements of an

      // individual string is determined by _S_max_size. This is the

      // value that will be returned by max_size().  (Whereas npos

      // is the maximum number of bytes the allocator can allocate.)

      // If one was to divvy up the theoretical largest size string,

      // with a terminating character and m _CharT elements, it'd

      // look like this:

      // npos = m * sizeof(_CharT) + sizeof(_CharT)

      // Solving for m:

      // m = npos / sizeof(_CharT) - 1

      // In addition, this implementation quarters this amount.

      enum { _S_max_size = (((static_cast<size_type>(-1)

                              / sizeof(_CharT)) - 1) / 4) };

      // Data Members (private):

      typename _Util_Base::template _Alloc_hider<_CharT_alloc_type>

                                                            _M_dataplus;

      size_type                                             _M_string_length;

      enum { _S_local_capacity = 15 };

      union

      {

        _CharT           _M_local_data[_S_local_capacity + 1];

        size_type        _M_allocated_capacity;

      };

      void

      _M_data(_CharT* __p)

      { _M_dataplus._M_p = __p; }

      void

      _M_length(size_type __length)

      { _M_string_length = __length; }

      void

      _M_capacity(size_type __capacity)

      { _M_allocated_capacity = __capacity; }

      bool

      _M_is_local() const

      { return _M_data() == _M_local_data; }

      // Create & Destroy

      _CharT*

      _M_create(size_type&, size_type);

      void

      _M_dispose()

      {

        if (!_M_is_local())

          _M_destroy(_M_allocated_capacity);

      }

      void

      _M_destroy(size_type) throw();

      // _M_construct_aux is used to implement the 21.3.1 para 15 which

      // requires special behaviour if _InIterator is an integral type

      template<typename _InIterator>

        void

        _M_construct_aux(_InIterator __beg, _InIterator __end, __false_type)

        {

          typedef typename iterator_traits<_InIterator>::iterator_category _Tag;

          _M_construct(__beg, __end, _Tag());

        }

      template<typename _InIterator>

        void

        _M_construct_aux(_InIterator __beg, _InIterator __end, __true_type)

        { _M_construct(static_cast<size_type>(__beg),

                       static_cast<value_type>(__end)); }

      template<typename _InIterator>

        void

        _M_construct(_InIterator __beg, _InIterator __end)

        {

          typedef typename std::__is_integer<_InIterator>::__type _Integral;

          _M_construct_aux(__beg, __end, _Integral());

        }

      // For Input Iterators, used in istreambuf_iterators, etc.

      template<typename _InIterator>

        void

        _M_construct(_InIterator __beg, _InIterator __end,

                     std::input_iterator_tag);

      // For forward_iterators up to random_access_iterators, used for

      // string::iterator, _CharT*, etc.

      template<typename _FwdIterator>

        void

        _M_construct(_FwdIterator __beg, _FwdIterator __end,

                     std::forward_iterator_tag);

      void

      _M_construct(size_type __req, _CharT __c);

    public:

      size_type

      _M_max_size() const

      { return size_type(_S_max_size); }

      _CharT*

      _M_data() const

      { return _M_dataplus._M_p; }

      size_type

      _M_length() const

      { return _M_string_length; }

      size_type

      _M_capacity() const

      {

        return _M_is_local() ? size_type(_S_local_capacity)

                             : _M_allocated_capacity;

      }

      bool

      _M_is_shared() const

      { return false; }

      void

      _M_set_leaked() { }

      void

      _M_leak() { }

      void

      _M_set_length(size_type __n)

      {

        _M_length(__n);

        traits_type::assign(_M_data()[__n], _CharT());

      }

      __sso_string_base()

      : _M_dataplus(_Alloc(), _M_local_data)

      { _M_set_length(0); }

      __sso_string_base(const _Alloc& __a);

      __sso_string_base(const __sso_string_base& __rcs);

      __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a);

      template<typename _InputIterator>

        __sso_string_base(_InputIterator __beg, _InputIterator __end,

                          const _Alloc& __a);

      ~__sso_string_base()

      { _M_dispose(); }

      _CharT_alloc_type&

      _M_get_allocator()

      { return _M_dataplus; }

      const _CharT_alloc_type&

      _M_get_allocator() const

      { return _M_dataplus; }

      void

      _M_swap(__sso_string_base& __rcs);

      void

      _M_assign(const __sso_string_base& __rcs);

      void

      _M_reserve(size_type __res);

      void

      _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,

                size_type __len2);

      void

      _M_erase(size_type __pos, size_type __n);

      bool

      _M_compare(const __sso_string_base&) const

      { return false; }

    };

  template<typename _CharT, typename _Traits, typename _Alloc>

    void

    __sso_string_base<_CharT, _Traits, _Alloc>::

    _M_destroy(size_type __size) throw()

    { _M_dataplus._CharT_alloc_type::deallocate(_M_data(), __size + 1); }

  template<typename _CharT, typename _Traits, typename _Alloc>

    void

    __sso_string_base<_CharT, _Traits, _Alloc>::

    _M_swap(__sso_string_base& __rcs)

    {

      // NB: Implement Option 3 of DR 431 (see N1599).

      std::__alloc_swap<_CharT_alloc_type>::_S_do_it(_M_get_allocator(),

                                                     __rcs._M_get_allocator());

      if (_M_is_local())

        if (__rcs._M_is_local())

          {

            if (_M_length() && __rcs._M_length())

              {

                _CharT __tmp_data[_S_local_capacity + 1];

                traits_type::copy(__tmp_data, __rcs._M_local_data,

                                  _S_local_capacity + 1);

                traits_type::copy(__rcs._M_local_data, _M_local_data,

                                  _S_local_capacity + 1);

                traits_type::copy(_M_local_data, __tmp_data,

                                  _S_local_capacity + 1);

              }

            else if (__rcs._M_length())

              {

                traits_type::copy(_M_local_data, __rcs._M_local_data,

                                  _S_local_capacity + 1);

                _M_length(__rcs._M_length());

                __rcs._M_set_length(0);

                return;

              }

            else if (_M_length())

              {

                traits_type::copy(__rcs._M_local_data, _M_local_data,

                                  _S_local_capacity + 1);

                __rcs._M_length(_M_length());

                _M_set_length(0);

                return;

              }

          }

        else

          {

            const size_type __tmp_capacity = __rcs._M_allocated_capacity;

            traits_type::copy(__rcs._M_local_data, _M_local_data,

                              _S_local_capacity + 1);

            _M_data(__rcs._M_data());

            __rcs._M_data(__rcs._M_local_data);

            _M_capacity(__tmp_capacity);

          }

      else

        {

          const size_type __tmp_capacity = _M_allocated_capacity;

          if (__rcs._M_is_local())

            {

              traits_type::copy(_M_local_data, __rcs._M_local_data,

                                _S_local_capacity + 1);

              __rcs._M_data(_M_data());

              _M_data(_M_local_data);

            }

          else

            {

              _CharT* __tmp_ptr = _M_data();

              _M_data(__rcs._M_data());

              __rcs._M_data(__tmp_ptr);

              _M_capacity(__rcs._M_allocated_capacity);

            }

          __rcs._M_capacity(__tmp_capacity);

        }

      const size_type __tmp_length = _M_length();

      _M_length(__rcs._M_length());

      __rcs._M_length(__tmp_length);

    }

  template<typename _CharT, typename _Traits, typename _Alloc>

    _CharT*

    __sso_string_base<_CharT, _Traits, _Alloc>::

    _M_create(size_type& __capacity, size_type __old_capacity)

    {

      // _GLIBCXX_RESOLVE_LIB_DEFECTS

      // 83.  String::npos vs. string::max_size()

      if (__capacity > size_type(_S_max_size))

        std::__throw_length_error(__N("__sso_string_base::_M_create"));

      // The below implements an exponential growth policy, necessary to

      // meet amortized linear time requirements of the library: see

      // http://gcc.gnu.org/ml/libstdc++/2001-07/msg00085.html.

      if (__capacity > __old_capacity && __capacity < 2 * __old_capacity)

        __capacity = 2 * __old_capacity;

      // NB: Need an array of char_type[__capacity], plus a terminating

      // null char_type() element.

      return _M_dataplus._CharT_alloc_type::allocate(__capacity + 1);

    }

  template<typename _CharT, typename _Traits, typename _Alloc>

    __sso_string_base<_CharT, _Traits, _Alloc>::

    __sso_string_base(const _Alloc& __a)

    : _M_dataplus(__a, _M_local_data)

    { _M_set_length(0); }

  template<typename _CharT, typename _Traits, typename _Alloc>

    __sso_string_base<_CharT, _Traits, _Alloc>::

    __sso_string_base(const __sso_string_base& __rcs)

    : _M_dataplus(__rcs._M_get_allocator(), _M_local_data)

    { _M_construct(__rcs._M_data(), __rcs._M_data() + __rcs._M_length()); }

  template<typename _CharT, typename _Traits, typename _Alloc>

    __sso_string_base<_CharT, _Traits, _Alloc>::

    __sso_string_base(size_type __n, _CharT __c, const _Alloc& __a)

    : _M_dataplus(__a, _M_local_data)

    { _M_construct(__n, __c); }

  template<typename _CharT, typename _Traits, typename _Alloc>

    template<typename _InputIterator>

    __sso_string_base<_CharT, _Traits, _Alloc>::

    __sso_string_base(_InputIterator __beg, _InputIterator __end,

                      const _Alloc& __a)

    : _M_dataplus(__a, _M_local_data)

    { _M_construct(__beg, __end); }

  // NB: This is the special case for Input Iterators, used in

  // istreambuf_iterators, etc.

  // Input Iterators have a cost structure very different from

  // pointers, calling for a different coding style.

  template<typename _CharT, typename _Traits, typename _Alloc>

    template<typename _InIterator>

      void

      __sso_string_base<_CharT, _Traits, _Alloc>::

      _M_construct(_InIterator __beg, _InIterator __end,

                   std::input_iterator_tag)

      {

        size_type __len = 0;

        size_type __capacity = size_type(_S_local_capacity);

        while (__beg != __end && __len < __capacity)

          {

            _M_data()[__len++] = *__beg;

            ++__beg;

          }

        try

          {

            while (__beg != __end)

              {

                if (__len == __capacity)

                  {

                    // Allocate more space.

                    __capacity = __len + 1;

                    _CharT* __another = _M_create(__capacity, __len);

                    _S_copy(__another, _M_data(), __len);

                    _M_dispose();

                    _M_data(__another);

                    _M_capacity(__capacity);

                  }

                _M_data()[__len++] = *__beg;

                ++__beg;

              }

          }

        catch(...)

          {

            _M_dispose();

            __throw_exception_again;

          }

        _M_set_length(__len);

      }

  template<typename _CharT, typename _Traits, typename _Alloc>

    template<typename _InIterator>

      void

      __sso_string_base<_CharT, _Traits, _Alloc>::

      _M_construct(_InIterator __beg, _InIterator __end,

                   std::forward_iterator_tag)

      {

        // NB: Not required, but considered best practice.

        if (__builtin_expect(_S_is_null_pointer(__beg) && __beg != __end, 0))

          std::__throw_logic_error(__N("__sso_string_base::"

                                       "_M_construct NULL not valid"));

        size_type __dnew = static_cast<size_type>(std::distance(__beg, __end));

        if (__dnew > size_type(_S_local_capacity))

          {

            _M_data(_M_create(__dnew, size_type(0)));

            _M_capacity(__dnew);

          }

        // Check for out_of_range and length_error exceptions.

        try

          { _S_copy_chars(_M_data(), __beg, __end); }

        catch(...)

          {

            _M_dispose();

            __throw_exception_again;

          }

        _M_set_length(__dnew);

      }

  template<typename _CharT, typename _Traits, typename _Alloc>

    void

    __sso_string_base<_CharT, _Traits, _Alloc>::

    _M_construct(size_type __n, _CharT __c)

    {

      if (__n > size_type(_S_local_capacity))

        {

          _M_data(_M_create(__n, size_type(0)));

          _M_capacity(__n);

        }

      if (__n)

        _S_assign(_M_data(), __n, __c);

      _M_set_length(__n);

    }

  template<typename _CharT, typename _Traits, typename _Alloc>

    void

    __sso_string_base<_CharT, _Traits, _Alloc>::

    _M_assign(const __sso_string_base& __rcs)

    {

      if (this != &__rcs)

        {

          const size_type __rsize = __rcs._M_length();

          const size_type __capacity = _M_capacity();

          if (__rsize > __capacity)

            {

              size_type __new_capacity = __rsize;

              _CharT* __tmp = _M_create(__new_capacity, __capacity);

              _M_dispose();

              _M_data(__tmp);

              _M_capacity(__new_capacity);

            }

          if (__rsize)

            _S_copy(_M_data(), __rcs._M_data(), __rsize);

          _M_set_length(__rsize);

        }

    }

  template<typename _CharT, typename _Traits, typename _Alloc>

    void

    __sso_string_base<_CharT, _Traits, _Alloc>::

    _M_reserve(size_type __res)

    {

      // Make sure we don't shrink below the current size.

      if (__res < _M_length())

        __res = _M_length();

      const size_type __capacity = _M_capacity();

      if (__res != __capacity)

        {

          if (__res > __capacity

              || __res > size_type(_S_local_capacity))

            {

              _CharT* __tmp = _M_create(__res, __capacity);

              _S_copy(__tmp, _M_data(), _M_length() + 1);

              _M_dispose();

              _M_data(__tmp);

              _M_capacity(__res);

            }

          else if (!_M_is_local())

            {

              _S_copy(_M_local_data, _M_data(), _M_length() + 1);

              _M_destroy(__capacity);

              _M_data(_M_local_data);

            }

        }

    }

  template<typename _CharT, typename _Traits, typename _Alloc>

    void

    __sso_string_base<_CharT, _Traits, _Alloc>::

    _M_mutate(size_type __pos, size_type __len1, const _CharT* __s,

              const size_type __len2)

    {

      const size_type __how_much = _M_length() - __pos - __len1;

      size_type __new_capacity = _M_length() + __len2 - __len1;

      _CharT* __r = _M_create(__new_capacity, _M_capacity());

      if (__pos)

        _S_copy(__r, _M_data(), __pos);

      if (__s && __len2)

        _S_copy(__r + __pos, __s, __len2);

      if (__how_much)

        _S_copy(__r + __pos + __len2,

                _M_data() + __pos + __len1, __how_much);

      _M_dispose();

      _M_data(__r);

      _M_capacity(__new_capacity);

    }

  template<typename _CharT, typename _Traits, typename _Alloc>

    void

    __sso_string_base<_CharT, _Traits, _Alloc>::

    _M_erase(size_type __pos, size_type __n)

    {

      const size_type __how_much = _M_length() - __pos - __n;

      if (__how_much && __n)

        _S_move(_M_data() + __pos, _M_data() + __pos + __n,

                __how_much);

      _M_set_length(_M_length() - __n);

    }

  template<>

    inline bool

    __sso_string_base<char, std::char_traits<char>,

                      std::allocator<char> >::

    _M_compare(const __sso_string_base& __rcs) const

    {

      if (this == &__rcs)

        return true;

      return false;

    }

  template<>

    inline bool

    __sso_string_base<wchar_t, std::char_traits<wchar_t>,

                      std::allocator<wchar_t> >::

    _M_compare(const __sso_string_base& __rcs) const

    {

      if (this == &__rcs)

        return true;

      return false;

    }

} // namespace __gnu_cxx

#endif /* _SSO_STRING_BASE_H */