diff options
Diffstat (limited to 'gcc-4.4.3/libstdc++-v3/include/ext/rc_string_base.h')
| -rw-r--r-- | gcc-4.4.3/libstdc++-v3/include/ext/rc_string_base.h | 718 |
1 files changed, 718 insertions, 0 deletions
diff --git a/gcc-4.4.3/libstdc++-v3/include/ext/rc_string_base.h b/gcc-4.4.3/libstdc++-v3/include/ext/rc_string_base.h new file mode 100644 index 000000000..dce5e0671 --- /dev/null +++ b/gcc-4.4.3/libstdc++-v3/include/ext/rc_string_base.h @@ -0,0 +1,718 @@ +// Reference-counted versatile string base -*- C++ -*- + +// Copyright (C) 2005, 2006, 2007, 2008, 2009 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 3, 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. + +// Under Section 7 of GPL version 3, you are granted additional +// permissions described in the GCC Runtime Library Exception, version +// 3.1, as published by the Free Software Foundation. + +// You should have received a copy of the GNU General Public License and +// a copy of the GCC Runtime Library Exception along with this program; +// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see +// <http://www.gnu.org/licenses/>. + +/** @file ext/rc_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 _RC_STRING_BASE_H +#define _RC_STRING_BASE_H 1 + +#include <ext/atomicity.h> +#include <bits/stl_iterator_base_funcs.h> + +_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) + + /** + * Documentation? What's that? + * Nathan Myers <ncm@cantrip.org>. + * + * A string looks like this: + * + * @code + * [_Rep] + * _M_length + * [__rc_string_base<char_type>] _M_capacity + * _M_dataplus _M_refcount + * _M_p ----------------> unnamed array of char_type + * @endcode + * + * Where the _M_p points to the first character in the string, and + * you cast it to a pointer-to-_Rep and subtract 1 to get a + * pointer to the header. + * + * This approach has the enormous advantage that a string object + * requires only one allocation. All the ugliness is confined + * within a single pair of inline functions, which each compile to + * a single "add" instruction: _Rep::_M_refdata(), and + * __rc_string_base::_M_rep(); and the allocation function which gets a + * block of raw bytes and with room enough and constructs a _Rep + * object at the front. + * + * The reason you want _M_data pointing to the character array and + * not the _Rep is so that the debugger can see the string + * contents. (Probably we should add a non-inline member to get + * the _Rep for the debugger to use, so users can check the actual + * string length.) + * + * Note that the _Rep object is a POD so that you can have a + * static "empty string" _Rep object already "constructed" before + * static constructors have run. The reference-count encoding is + * chosen so that a 0 indicates one reference, so you never try to + * destroy the empty-string _Rep object. + * + * All but the last paragraph is considered pretty conventional + * for a C++ string implementation. + */ + template<typename _CharT, typename _Traits, typename _Alloc> + class __rc_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 __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: + // _Rep: string representation + // Invariants: + // 1. String really contains _M_length + 1 characters: due to 21.3.4 + // must be kept null-terminated. + // 2. _M_capacity >= _M_length + // Allocated memory is always (_M_capacity + 1) * sizeof(_CharT). + // 3. _M_refcount has three states: + // -1: leaked, one reference, no ref-copies allowed, non-const. + // 0: one reference, non-const. + // n>0: n + 1 references, operations require a lock, const. + // 4. All fields == 0 is an empty string, given the extra storage + // beyond-the-end for a null terminator; thus, the shared + // empty string representation needs no constructor. + struct _Rep + { + union + { + struct + { + size_type _M_length; + size_type _M_capacity; + _Atomic_word _M_refcount; + } _M_info; + + // Only for alignment purposes. + _CharT _M_align; + }; + + typedef typename _Alloc::template rebind<_Rep>::other _Rep_alloc_type; + + _CharT* + _M_refdata() throw() + { return reinterpret_cast<_CharT*>(this + 1); } + + _CharT* + _M_refcopy() throw() + { + __atomic_add_dispatch(&_M_info._M_refcount, 1); + return _M_refdata(); + } // XXX MT + + void + _M_set_length(size_type __n) + { + _M_info._M_refcount = 0; // One reference. + _M_info._M_length = __n; + // grrr. (per 21.3.4) + // You cannot leave those LWG people alone for a second. + traits_type::assign(_M_refdata()[__n], _CharT()); + } + + // Create & Destroy + static _Rep* + _S_create(size_type, size_type, const _Alloc&); + + void + _M_destroy(const _Alloc&) throw(); + + _CharT* + _M_clone(const _Alloc&, size_type __res = 0); + }; + + struct _Rep_empty + : public _Rep + { + _CharT _M_terminal; + }; + + static _Rep_empty _S_empty_rep; + + // 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 = sizeof(_Rep) + (m * sizeof(_CharT)) + sizeof(_CharT) + // + sizeof(_Rep) - 1 + // (NB: last two terms for rounding reasons, see _M_create below) + // Solving for m: + // m = ((npos - 2 * sizeof(_Rep) + 1) / sizeof(_CharT)) - 1 + // In addition, this implementation halves this amount. + enum { _S_max_size = (((static_cast<size_type>(-1) - 2 * sizeof(_Rep) + + 1) / sizeof(_CharT)) - 1) / 2 }; + + // Data Member (private): + mutable typename _Util_Base::template _Alloc_hider<_Alloc> _M_dataplus; + + void + _M_data(_CharT* __p) + { _M_dataplus._M_p = __p; } + + _Rep* + _M_rep() const + { return &((reinterpret_cast<_Rep*>(_M_data()))[-1]); } + + _CharT* + _M_grab(const _Alloc& __alloc) const + { + return (!_M_is_leaked() && _M_get_allocator() == __alloc) + ? _M_rep()->_M_refcopy() : _M_rep()->_M_clone(__alloc); + } + + void + _M_dispose() + { + if (__exchange_and_add_dispatch(&_M_rep()->_M_info._M_refcount, + -1) <= 0) + _M_rep()->_M_destroy(_M_get_allocator()); + } // XXX MT + + bool + _M_is_leaked() const + { return _M_rep()->_M_info._M_refcount < 0; } + + void + _M_set_sharable() + { _M_rep()->_M_info._M_refcount = 0; } + + void + _M_leak_hard(); + + // _S_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> + static _CharT* + _S_construct_aux(_InIterator __beg, _InIterator __end, + const _Alloc& __a, std::__false_type) + { + typedef typename iterator_traits<_InIterator>::iterator_category _Tag; + return _S_construct(__beg, __end, __a, _Tag()); + } + + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 438. Ambiguity in the "do the right thing" clause + template<typename _Integer> + static _CharT* + _S_construct_aux(_Integer __beg, _Integer __end, + const _Alloc& __a, std::__true_type) + { return _S_construct(static_cast<size_type>(__beg), __end, __a); } + + template<typename _InIterator> + static _CharT* + _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a) + { + typedef typename std::__is_integer<_InIterator>::__type _Integral; + return _S_construct_aux(__beg, __end, __a, _Integral()); + } + + // For Input Iterators, used in istreambuf_iterators, etc. + template<typename _InIterator> + static _CharT* + _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a, + std::input_iterator_tag); + + // For forward_iterators up to random_access_iterators, used for + // string::iterator, _CharT*, etc. + template<typename _FwdIterator> + static _CharT* + _S_construct(_FwdIterator __beg, _FwdIterator __end, const _Alloc& __a, + std::forward_iterator_tag); + + static _CharT* + _S_construct(size_type __req, _CharT __c, const _Alloc& __a); + + 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_rep()->_M_info._M_length; } + + size_type + _M_capacity() const + { return _M_rep()->_M_info._M_capacity; } + + bool + _M_is_shared() const + { return _M_rep()->_M_info._M_refcount > 0; } + + void + _M_set_leaked() + { _M_rep()->_M_info._M_refcount = -1; } + + void + _M_leak() // for use in begin() & non-const op[] + { + if (!_M_is_leaked()) + _M_leak_hard(); + } + + void + _M_set_length(size_type __n) + { _M_rep()->_M_set_length(__n); } + + __rc_string_base() + : _M_dataplus(_S_empty_rep._M_refcopy()) { } + + __rc_string_base(const _Alloc& __a); + + __rc_string_base(const __rc_string_base& __rcs); + +#ifdef __GXX_EXPERIMENTAL_CXX0X__ + __rc_string_base(__rc_string_base&& __rcs) + : _M_dataplus(__rcs._M_get_allocator(), __rcs._M_data()) + { __rcs._M_data(_S_empty_rep._M_refcopy()); } +#endif + + __rc_string_base(size_type __n, _CharT __c, const _Alloc& __a); + + template<typename _InputIterator> + __rc_string_base(_InputIterator __beg, _InputIterator __end, + const _Alloc& __a); + + ~__rc_string_base() + { _M_dispose(); } + + allocator_type& + _M_get_allocator() + { return _M_dataplus; } + + const allocator_type& + _M_get_allocator() const + { return _M_dataplus; } + + void + _M_swap(__rc_string_base& __rcs); + + void + _M_assign(const __rc_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); + + void + _M_clear() + { _M_erase(size_type(0), _M_length()); } + + bool + _M_compare(const __rc_string_base&) const + { return false; } + }; + + template<typename _CharT, typename _Traits, typename _Alloc> + typename __rc_string_base<_CharT, _Traits, _Alloc>::_Rep_empty + __rc_string_base<_CharT, _Traits, _Alloc>::_S_empty_rep; + + template<typename _CharT, typename _Traits, typename _Alloc> + typename __rc_string_base<_CharT, _Traits, _Alloc>::_Rep* + __rc_string_base<_CharT, _Traits, _Alloc>::_Rep:: + _S_create(size_type __capacity, size_type __old_capacity, + const _Alloc& __alloc) + { + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 83. String::npos vs. string::max_size() + if (__capacity > size_type(_S_max_size)) + std::__throw_length_error(__N("__rc_string_base::_Rep::_S_create")); + + // The standard places no restriction on allocating more memory + // than is strictly needed within this layer at the moment or as + // requested by an explicit application call to reserve(). + + // Many malloc implementations perform quite poorly when an + // application attempts to allocate memory in a stepwise fashion + // growing each allocation size by only 1 char. Additionally, + // it makes little sense to allocate less linear memory than the + // natural blocking size of the malloc implementation. + // Unfortunately, we would need a somewhat low-level calculation + // with tuned parameters to get this perfect for any particular + // malloc implementation. Fortunately, generalizations about + // common features seen among implementations seems to suffice. + + // __pagesize need not match the actual VM page size for good + // results in practice, thus we pick a common value on the low + // side. __malloc_header_size is an estimate of the amount of + // overhead per memory allocation (in practice seen N * sizeof + // (void*) where N is 0, 2 or 4). According to folklore, + // picking this value on the high side is better than + // low-balling it (especially when this algorithm is used with + // malloc implementations that allocate memory blocks rounded up + // to a size which is a power of 2). + const size_type __pagesize = 4096; + const size_type __malloc_header_size = 4 * sizeof(void*); + + // 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; + // Never allocate a string bigger than _S_max_size. + if (__capacity > size_type(_S_max_size)) + __capacity = size_type(_S_max_size); + } + + // NB: Need an array of char_type[__capacity], plus a terminating + // null char_type() element, plus enough for the _Rep data structure, + // plus sizeof(_Rep) - 1 to upper round to a size multiple of + // sizeof(_Rep). + // Whew. Seemingly so needy, yet so elemental. + size_type __size = ((__capacity + 1) * sizeof(_CharT) + + 2 * sizeof(_Rep) - 1); + + const size_type __adj_size = __size + __malloc_header_size; + if (__adj_size > __pagesize && __capacity > __old_capacity) + { + const size_type __extra = __pagesize - __adj_size % __pagesize; + __capacity += __extra / sizeof(_CharT); + if (__capacity > size_type(_S_max_size)) + __capacity = size_type(_S_max_size); + __size = (__capacity + 1) * sizeof(_CharT) + 2 * sizeof(_Rep) - 1; + } + + // NB: Might throw, but no worries about a leak, mate: _Rep() + // does not throw. + _Rep* __place = _Rep_alloc_type(__alloc).allocate(__size / sizeof(_Rep)); + _Rep* __p = new (__place) _Rep; + __p->_M_info._M_capacity = __capacity; + return __p; + } + + template<typename _CharT, typename _Traits, typename _Alloc> + void + __rc_string_base<_CharT, _Traits, _Alloc>::_Rep:: + _M_destroy(const _Alloc& __a) throw () + { + const size_type __size = ((_M_info._M_capacity + 1) * sizeof(_CharT) + + 2 * sizeof(_Rep) - 1); + _Rep_alloc_type(__a).deallocate(this, __size / sizeof(_Rep)); + } + + template<typename _CharT, typename _Traits, typename _Alloc> + _CharT* + __rc_string_base<_CharT, _Traits, _Alloc>::_Rep:: + _M_clone(const _Alloc& __alloc, size_type __res) + { + // Requested capacity of the clone. + const size_type __requested_cap = _M_info._M_length + __res; + _Rep* __r = _Rep::_S_create(__requested_cap, _M_info._M_capacity, + __alloc); + + if (_M_info._M_length) + _S_copy(__r->_M_refdata(), _M_refdata(), _M_info._M_length); + + __r->_M_set_length(_M_info._M_length); + return __r->_M_refdata(); + } + + template<typename _CharT, typename _Traits, typename _Alloc> + __rc_string_base<_CharT, _Traits, _Alloc>:: + __rc_string_base(const _Alloc& __a) + : _M_dataplus(__a, _S_construct(size_type(), _CharT(), __a)) { } + + template<typename _CharT, typename _Traits, typename _Alloc> + __rc_string_base<_CharT, _Traits, _Alloc>:: + __rc_string_base(const __rc_string_base& __rcs) + : _M_dataplus(__rcs._M_get_allocator(), + __rcs._M_grab(__rcs._M_get_allocator())) { } + + template<typename _CharT, typename _Traits, typename _Alloc> + __rc_string_base<_CharT, _Traits, _Alloc>:: + __rc_string_base(size_type __n, _CharT __c, const _Alloc& __a) + : _M_dataplus(__a, _S_construct(__n, __c, __a)) { } + + template<typename _CharT, typename _Traits, typename _Alloc> + template<typename _InputIterator> + __rc_string_base<_CharT, _Traits, _Alloc>:: + __rc_string_base(_InputIterator __beg, _InputIterator __end, + const _Alloc& __a) + : _M_dataplus(__a, _S_construct(__beg, __end, __a)) { } + + template<typename _CharT, typename _Traits, typename _Alloc> + void + __rc_string_base<_CharT, _Traits, _Alloc>:: + _M_leak_hard() + { + if (_M_is_shared()) + _M_erase(0, 0); + _M_set_leaked(); + } + + // 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> + _CharT* + __rc_string_base<_CharT, _Traits, _Alloc>:: + _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a, + std::input_iterator_tag) + { + if (__beg == __end && __a == _Alloc()) + return _S_empty_rep._M_refcopy(); + + // Avoid reallocation for common case. + _CharT __buf[128]; + size_type __len = 0; + while (__beg != __end && __len < sizeof(__buf) / sizeof(_CharT)) + { + __buf[__len++] = *__beg; + ++__beg; + } + _Rep* __r = _Rep::_S_create(__len, size_type(0), __a); + _S_copy(__r->_M_refdata(), __buf, __len); + __try + { + while (__beg != __end) + { + if (__len == __r->_M_info._M_capacity) + { + // Allocate more space. + _Rep* __another = _Rep::_S_create(__len + 1, __len, __a); + _S_copy(__another->_M_refdata(), __r->_M_refdata(), __len); + __r->_M_destroy(__a); + __r = __another; + } + __r->_M_refdata()[__len++] = *__beg; + ++__beg; + } + } + __catch(...) + { + __r->_M_destroy(__a); + __throw_exception_again; + } + __r->_M_set_length(__len); + return __r->_M_refdata(); + } + + template<typename _CharT, typename _Traits, typename _Alloc> + template<typename _InIterator> + _CharT* + __rc_string_base<_CharT, _Traits, _Alloc>:: + _S_construct(_InIterator __beg, _InIterator __end, const _Alloc& __a, + std::forward_iterator_tag) + { + if (__beg == __end && __a == _Alloc()) + return _S_empty_rep._M_refcopy(); + + // NB: Not required, but considered best practice. + if (__builtin_expect(__is_null_pointer(__beg) && __beg != __end, 0)) + std::__throw_logic_error(__N("__rc_string_base::" + "_S_construct NULL not valid")); + + const size_type __dnew = static_cast<size_type>(std::distance(__beg, + __end)); + // Check for out_of_range and length_error exceptions. + _Rep* __r = _Rep::_S_create(__dnew, size_type(0), __a); + __try + { _S_copy_chars(__r->_M_refdata(), __beg, __end); } + __catch(...) + { + __r->_M_destroy(__a); + __throw_exception_again; + } + __r->_M_set_length(__dnew); + return __r->_M_refdata(); + } + + template<typename _CharT, typename _Traits, typename _Alloc> + _CharT* + __rc_string_base<_CharT, _Traits, _Alloc>:: + _S_construct(size_type __n, _CharT __c, const _Alloc& __a) + { + if (__n == 0 && __a == _Alloc()) + return _S_empty_rep._M_refcopy(); + + // Check for out_of_range and length_error exceptions. + _Rep* __r = _Rep::_S_create(__n, size_type(0), __a); + if (__n) + _S_assign(__r->_M_refdata(), __n, __c); + + __r->_M_set_length(__n); + return __r->_M_refdata(); + } + + template<typename _CharT, typename _Traits, typename _Alloc> + void + __rc_string_base<_CharT, _Traits, _Alloc>:: + _M_swap(__rc_string_base& __rcs) + { + if (_M_is_leaked()) + _M_set_sharable(); + if (__rcs._M_is_leaked()) + __rcs._M_set_sharable(); + + _CharT* __tmp = _M_data(); + _M_data(__rcs._M_data()); + __rcs._M_data(__tmp); + + // _GLIBCXX_RESOLVE_LIB_DEFECTS + // 431. Swapping containers with unequal allocators. + std::__alloc_swap<allocator_type>::_S_do_it(_M_get_allocator(), + __rcs._M_get_allocator()); + } + + template<typename _CharT, typename _Traits, typename _Alloc> + void + __rc_string_base<_CharT, _Traits, _Alloc>:: + _M_assign(const __rc_string_base& __rcs) + { + if (_M_rep() != __rcs._M_rep()) + { + _CharT* __tmp = __rcs._M_grab(_M_get_allocator()); + _M_dispose(); + _M_data(__tmp); + } + } + + template<typename _CharT, typename _Traits, typename _Alloc> + void + __rc_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(); + + if (__res != _M_capacity() || _M_is_shared()) + { + _CharT* __tmp = _M_rep()->_M_clone(_M_get_allocator(), + __res - _M_length()); + _M_dispose(); + _M_data(__tmp); + } + } + + template<typename _CharT, typename _Traits, typename _Alloc> + void + __rc_string_base<_CharT, _Traits, _Alloc>:: + _M_mutate(size_type __pos, size_type __len1, const _CharT* __s, + size_type __len2) + { + const size_type __how_much = _M_length() - __pos - __len1; + + _Rep* __r = _Rep::_S_create(_M_length() + __len2 - __len1, + _M_capacity(), _M_get_allocator()); + + if (__pos) + _S_copy(__r->_M_refdata(), _M_data(), __pos); + if (__s && __len2) + _S_copy(__r->_M_refdata() + __pos, __s, __len2); + if (__how_much) + _S_copy(__r->_M_refdata() + __pos + __len2, + _M_data() + __pos + __len1, __how_much); + + _M_dispose(); + _M_data(__r->_M_refdata()); + } + + template<typename _CharT, typename _Traits, typename _Alloc> + void + __rc_string_base<_CharT, _Traits, _Alloc>:: + _M_erase(size_type __pos, size_type __n) + { + const size_type __new_size = _M_length() - __n; + const size_type __how_much = _M_length() - __pos - __n; + + if (_M_is_shared()) + { + // Must reallocate. + _Rep* __r = _Rep::_S_create(__new_size, _M_capacity(), + _M_get_allocator()); + + if (__pos) + _S_copy(__r->_M_refdata(), _M_data(), __pos); + if (__how_much) + _S_copy(__r->_M_refdata() + __pos, + _M_data() + __pos + __n, __how_much); + + _M_dispose(); + _M_data(__r->_M_refdata()); + } + else if (__how_much && __n) + { + // Work in-place. + _S_move(_M_data() + __pos, + _M_data() + __pos + __n, __how_much); + } + + _M_rep()->_M_set_length(__new_size); + } + + template<> + inline bool + __rc_string_base<char, std::char_traits<char>, + std::allocator<char> >:: + _M_compare(const __rc_string_base& __rcs) const + { + if (_M_rep() == __rcs._M_rep()) + return true; + return false; + } + +#ifdef _GLIBCXX_USE_WCHAR_T + template<> + inline bool + __rc_string_base<wchar_t, std::char_traits<wchar_t>, + std::allocator<wchar_t> >:: + _M_compare(const __rc_string_base& __rcs) const + { + if (_M_rep() == __rcs._M_rep()) + return true; + return false; + } +#endif + +_GLIBCXX_END_NAMESPACE + +#endif /* _RC_STRING_BASE_H */ |