1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/epoc32/include/stdapis/boost/detail/quick_allocator.hpp Tue Mar 16 16:12:26 2010 +0000
1.3 @@ -0,0 +1,198 @@
1.4 +#ifndef BOOST_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED
1.5 +#define BOOST_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED
1.6 +
1.7 +// MS compatible compilers support #pragma once
1.8 +
1.9 +#if defined(_MSC_VER) && (_MSC_VER >= 1020)
1.10 +# pragma once
1.11 +#endif
1.12 +
1.13 +//
1.14 +// detail/quick_allocator.hpp
1.15 +//
1.16 +// Copyright (c) 2003 David Abrahams
1.17 +// Copyright (c) 2003 Peter Dimov
1.18 +//
1.19 +// Distributed under the Boost Software License, Version 1.0. (See
1.20 +// accompanying file LICENSE_1_0.txt or copy at
1.21 +// http://www.boost.org/LICENSE_1_0.txt)
1.22 +//
1.23 +
1.24 +#include <boost/config.hpp>
1.25 +
1.26 +#include <boost/detail/lightweight_mutex.hpp>
1.27 +#include <boost/type_traits/type_with_alignment.hpp>
1.28 +#include <boost/type_traits/alignment_of.hpp>
1.29 +
1.30 +#include <new> // ::operator new, ::operator delete
1.31 +#include <cstddef> // std::size_t
1.32 +
1.33 +namespace boost
1.34 +{
1.35 +
1.36 +namespace detail
1.37 +{
1.38 +
1.39 +template<unsigned size, unsigned align_> union freeblock
1.40 +{
1.41 + typedef typename boost::type_with_alignment<align_>::type aligner_type;
1.42 + aligner_type aligner;
1.43 + char bytes[size];
1.44 + freeblock * next;
1.45 +};
1.46 +
1.47 +template<unsigned size, unsigned align_> struct allocator_impl
1.48 +{
1.49 + typedef freeblock<size, align_> block;
1.50 +
1.51 + // It may seem odd to use such small pages.
1.52 + //
1.53 + // However, on a typical Windows implementation that uses
1.54 + // the OS allocator, "normal size" pages interact with the
1.55 + // "ordinary" operator new, slowing it down dramatically.
1.56 + //
1.57 + // 512 byte pages are handled by the small object allocator,
1.58 + // and don't interfere with ::new.
1.59 + //
1.60 + // The other alternative is to use much bigger pages (1M.)
1.61 + //
1.62 + // It is surprisingly easy to hit pathological behavior by
1.63 + // varying the page size. g++ 2.96 on Red Hat Linux 7.2,
1.64 + // for example, passionately dislikes 496. 512 seems OK.
1.65 +
1.66 +#if defined(BOOST_QA_PAGE_SIZE)
1.67 +
1.68 + enum { items_per_page = BOOST_QA_PAGE_SIZE / size };
1.69 +
1.70 +#else
1.71 +
1.72 + enum { items_per_page = 512 / size }; // 1048560 / size
1.73 +
1.74 +#endif
1.75 +
1.76 +#ifdef BOOST_HAS_THREADS
1.77 +
1.78 + static lightweight_mutex & mutex()
1.79 + {
1.80 + static lightweight_mutex m;
1.81 + return m;
1.82 + }
1.83 +
1.84 + static lightweight_mutex * mutex_init;
1.85 +
1.86 +#endif
1.87 +
1.88 + static block * free;
1.89 + static block * page;
1.90 + static unsigned last;
1.91 +
1.92 + static inline void * alloc()
1.93 + {
1.94 +#ifdef BOOST_HAS_THREADS
1.95 + lightweight_mutex::scoped_lock lock( mutex() );
1.96 +#endif
1.97 + if(block * x = free)
1.98 + {
1.99 + free = x->next;
1.100 + return x;
1.101 + }
1.102 + else
1.103 + {
1.104 + if(last == items_per_page)
1.105 + {
1.106 + // "Listen to me carefully: there is no memory leak"
1.107 + // -- Scott Meyers, Eff C++ 2nd Ed Item 10
1.108 + page = ::new block[items_per_page];
1.109 + last = 0;
1.110 + }
1.111 +
1.112 + return &page[last++];
1.113 + }
1.114 + }
1.115 +
1.116 + static inline void * alloc(std::size_t n)
1.117 + {
1.118 + if(n != size) // class-specific new called for a derived object
1.119 + {
1.120 + return ::operator new(n);
1.121 + }
1.122 + else
1.123 + {
1.124 +#ifdef BOOST_HAS_THREADS
1.125 + lightweight_mutex::scoped_lock lock( mutex() );
1.126 +#endif
1.127 + if(block * x = free)
1.128 + {
1.129 + free = x->next;
1.130 + return x;
1.131 + }
1.132 + else
1.133 + {
1.134 + if(last == items_per_page)
1.135 + {
1.136 + page = ::new block[items_per_page];
1.137 + last = 0;
1.138 + }
1.139 +
1.140 + return &page[last++];
1.141 + }
1.142 + }
1.143 + }
1.144 +
1.145 + static inline void dealloc(void * pv)
1.146 + {
1.147 + if(pv != 0) // 18.4.1.1/13
1.148 + {
1.149 +#ifdef BOOST_HAS_THREADS
1.150 + lightweight_mutex::scoped_lock lock( mutex() );
1.151 +#endif
1.152 + block * pb = static_cast<block *>(pv);
1.153 + pb->next = free;
1.154 + free = pb;
1.155 + }
1.156 + }
1.157 +
1.158 + static inline void dealloc(void * pv, std::size_t n)
1.159 + {
1.160 + if(n != size) // class-specific delete called for a derived object
1.161 + {
1.162 + ::operator delete(pv);
1.163 + }
1.164 + else if(pv != 0) // 18.4.1.1/13
1.165 + {
1.166 +#ifdef BOOST_HAS_THREADS
1.167 + lightweight_mutex::scoped_lock lock( mutex() );
1.168 +#endif
1.169 + block * pb = static_cast<block *>(pv);
1.170 + pb->next = free;
1.171 + free = pb;
1.172 + }
1.173 + }
1.174 +};
1.175 +
1.176 +#ifdef BOOST_HAS_THREADS
1.177 +
1.178 +template<unsigned size, unsigned align_>
1.179 + lightweight_mutex * allocator_impl<size, align_>::mutex_init = &allocator_impl<size, align_>::mutex();
1.180 +
1.181 +#endif
1.182 +
1.183 +template<unsigned size, unsigned align_>
1.184 + freeblock<size, align_> * allocator_impl<size, align_>::free = 0;
1.185 +
1.186 +template<unsigned size, unsigned align_>
1.187 + freeblock<size, align_> * allocator_impl<size, align_>::page = 0;
1.188 +
1.189 +template<unsigned size, unsigned align_>
1.190 + unsigned allocator_impl<size, align_>::last = allocator_impl<size, align_>::items_per_page;
1.191 +
1.192 +template<class T>
1.193 +struct quick_allocator: public allocator_impl< sizeof(T), boost::alignment_of<T>::value >
1.194 +{
1.195 +};
1.196 +
1.197 +} // namespace detail
1.198 +
1.199 +} // namespace boost
1.200 +
1.201 +#endif // #ifndef BOOST_DETAIL_QUICK_ALLOCATOR_HPP_INCLUDED