gcc/libstdc++-v3/include/ext/sso_string_base.h
Paolo Carlini c54c1b2b52 sso_string_base.h (struct __sso_string_local): Remove...
2005-10-05  Paolo Carlini  <pcarlini@suse.de>

	* include/ext/sso_string_base.h (struct __sso_string_local):
	Remove, actually POD types cannot have user defined constructors
	(being aggregates) and therefore can always be members of unions.
	(class __sso_string_base): Adjust consistently.

From-SVN: r105021
2005-10-05 23:50:18 +00:00

553 lines
16 KiB
C++

// Short-string-optimized versatile string base -*- C++ -*-
// Copyright (C) 2005 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 _Alloc allocator_type;
typedef typename __vstring_utility<_CharT, _Traits, _Alloc>::
_CharT_alloc_type _CharT_alloc_type;
typedef typename _CharT_alloc_type::size_type size_type;
// 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.
static const size_type _S_max_size;
private:
static const _CharT _S_terminal;
// Use empty-base optimization: http://www.cantrip.org/emptyopt.html
struct _Alloc_hider : _Alloc
{
_Alloc_hider(const _Alloc& __a, _CharT* __ptr)
: _Alloc(__a), _M_p(__ptr) { }
_CharT* _M_p; // The actual data.
};
// Data Members (private):
_Alloc_hider _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;
};
_CharT*
_M_data(_CharT* __p)
{ return (_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() throw()
{
if (!_M_is_local())
_M_destroy(_M_allocated_capacity + 1);
}
void
_M_destroy(size_type) throw();
// _M_construct_aux is used to implement the 21.3.1 para 15 which
// requires special behaviour if _InIter is an integral type
template<class _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<class _InIterator>
void
_M_construct_aux(_InIterator __beg, _InIterator __end, __true_type)
{ _M_construct(static_cast<size_type>(__beg),
static_cast<value_type>(__end)); }
template<class _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<class _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<class _FwdIterator>
void
_M_construct(_FwdIterator __beg, _FwdIterator __end,
std::forward_iterator_tag);
void
_M_construct(size_type __req, _CharT __c);
public:
_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; }
bool
_M_is_leaked() const
{ return false; }
void
_M_set_sharable() { }
void
_M_set_leaked() { }
void
_M_set_length(size_type __n)
{
_M_length(__n);
// grrr. (per 21.3.4)
// You cannot leave those LWG people alone for a second.
traits_type::assign(_M_data()[__n], _S_terminal);
}
void
_M_leak() { }
__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(); }
allocator_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, size_type __len2);
};
template<typename _CharT, typename _Traits, typename _Alloc>
void
__sso_string_base<_CharT, _Traits, _Alloc>::
_M_destroy(size_type __size) throw()
{ _CharT_alloc_type(_M_get_allocator()).deallocate(_M_data(), __size); }
template<typename _CharT, typename _Traits, typename _Alloc>
void
__sso_string_base<_CharT, _Traits, _Alloc>::
_M_swap(__sso_string_base& __rcs)
{
const bool __local = _M_is_local();
const bool __rcs_local = __rcs._M_is_local();
if (__local && __rcs_local)
{
_CharT __tmp_data[_S_local_capacity + 1];
const size_type __tmp_length = __rcs._M_length();
_S_copy(__tmp_data, __rcs._M_data(), __rcs._M_length() + 1);
__rcs._M_length(_M_length());
_S_copy(__rcs._M_data(), _M_data(), _M_length() + 1);
_M_length(__tmp_length);
_S_copy(_M_data(), __tmp_data, __tmp_length + 1);
}
else if (__local && !__rcs_local)
{
const size_type __tmp_capacity = __rcs._M_allocated_capacity;
const size_type __tmp_length = __rcs._M_length();
_CharT* __tmp_ptr = __rcs._M_data();
__rcs._M_data(__rcs._M_local_data);
_S_copy(__rcs._M_data(), _M_data(), _M_length() + 1);
__rcs._M_length(_M_length());
_M_data(__tmp_ptr);
_M_length(__tmp_length);
_M_capacity(__tmp_capacity);
}
else if (!__local && __rcs_local)
{
const size_type __tmp_capacity = _M_allocated_capacity;
const size_type __tmp_length = _M_length();
_CharT* __tmp_ptr = _M_data();
_M_data(_M_local_data);
_S_copy(_M_data(), __rcs._M_data(), __rcs._M_length() + 1);
_M_length(__rcs._M_length());
__rcs._M_data(__tmp_ptr);
__rcs._M_length(__tmp_length);
__rcs._M_capacity(__tmp_capacity);
}
else
{
const size_type __tmp_capacity = _M_allocated_capacity;
const size_type __tmp_length = _M_length();
_CharT* __tmp_ptr = _M_data();
_M_data(__rcs._M_data());
_M_length(__rcs._M_length());
_M_capacity(__rcs._M_allocated_capacity);
__rcs._M_data(__tmp_ptr);
__rcs._M_length(__tmp_length);
__rcs._M_capacity(__tmp_capacity);
}
}
template<typename _CharT, typename _Traits, typename _Alloc>
const typename __sso_string_base<_CharT, _Traits, _Alloc>::size_type
__sso_string_base<_CharT, _Traits, _Alloc>::
_S_max_size = ((static_cast<size_type>(-1) / sizeof(_CharT)) - 1) / 4;
template<typename _CharT, typename _Traits, typename _Alloc>
const _CharT
__sso_string_base<_CharT, _Traits, _Alloc>::_S_terminal = _CharT();
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 > _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.
// It's active for allocations requiring an amount of memory above
// system pagesize. This is consistent with the requirements of the
// standard: http://gcc.gnu.org/ml/libstdc++/2001-07/msg00130.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 _CharT_alloc_type(_M_get_allocator()).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)
{
// Avoid reallocation for common case.
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(__is_null_p(__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)
{
size_type __size = __rcs._M_length();
_CharT* __tmp = _M_local_data;
if (__size > size_type(_S_local_capacity))
__tmp = _M_create(__size, size_type(0));
_M_dispose();
_M_data(__tmp);
if (__size)
_S_copy(_M_data(), __rcs._M_data(), __size);
if (!_M_is_local())
_M_capacity(__size);
_M_set_length(__size);
}
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
__sso_string_base<_CharT, _Traits, _Alloc>::
_M_reserve(size_type __res)
{
const size_type __capacity = _M_capacity();
if (__res != __capacity)
{
// Make sure we don't shrink below the current size.
if (__res < _M_length())
__res = _M_length();
if (__res > __capacity
|| __res > size_type(_S_local_capacity))
{
_CharT* __tmp = _M_create(__res, __capacity);
if (_M_length())
_S_copy(__tmp, _M_data(), _M_length());
_M_dispose();
_M_data(__tmp);
_M_capacity(__res);
}
else if (!_M_is_local())
{
const size_type __tmp_capacity = _M_allocated_capacity;
if (_M_length())
_S_copy(_M_local_data, _M_data(), _M_length());
_M_destroy(__tmp_capacity + 1);
_M_data(_M_local_data);
}
_M_set_length(_M_length());
}
}
template<typename _CharT, typename _Traits, typename _Alloc>
void
__sso_string_base<_CharT, _Traits, _Alloc>::
_M_mutate(size_type __pos, size_type __len1, size_type __len2)
{
const size_type __old_size = _M_length();
const size_type __new_size = __old_size + __len2 - __len1;
const size_type __how_much = __old_size - __pos - __len1;
if (__new_size > _M_capacity())
{
// Must reallocate.
size_type __new_capacity = __new_size;
_CharT* __r = _M_create(__new_capacity, _M_capacity());
if (__pos)
_S_copy(__r, _M_data(), __pos);
if (__how_much)
_S_copy(__r + __pos + __len2,
_M_data() + __pos + __len1, __how_much);
_M_dispose();
_M_data(__r);
_M_capacity(__new_capacity);
}
else if (__how_much && __len1 != __len2)
{
// Work in-place.
_S_move(_M_data() + __pos + __len2,
_M_data() + __pos + __len1, __how_much);
}
_M_set_length(__new_size);
}
} // namespace __gnu_cxx
#endif /* _SSO_STRING_BASE_H */