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99 lines
3.6 KiB
C++
99 lines
3.6 KiB
C++
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// -*- Mode: C++; c-basic-offset: 2; indent-tabs-mode: nil -*-
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/* Copyright (c) 2006, Google Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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*
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following disclaimer
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* in the documentation and/or other materials provided with the
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* distribution.
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* * Neither the name of Google Inc. nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* ---
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* Author: Maxim Lifantsev
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*/
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#ifndef BASE_STL_ALLOCATOR_H_
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#define BASE_STL_ALLOCATOR_H_
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#include "../config.h"
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#include <stddef.h> // for ptrdiff_t
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#include <limits>
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#include "base/logging.h"
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// Generic allocator class for STL objects
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// that uses a given type-less allocator Alloc, which must provide:
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// static void* Alloc::Allocate(size_t size);
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// static void Alloc::Free(void* ptr, size_t size);
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//
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// STL_Allocator<T, MyAlloc> provides the same thread-safety
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// guarantees as MyAlloc.
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//
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// Usage example:
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// set<T, less<T>, STL_Allocator<T, MyAlloc> > my_set;
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// CAVEAT: Parts of the code below are probably specific
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// to the STL version(s) we are using.
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// The code is simply lifted from what std::allocator<> provides.
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template <typename T, class Alloc>
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class STL_Allocator {
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public:
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typedef size_t size_type;
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typedef ptrdiff_t difference_type;
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typedef T* pointer;
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typedef const T* const_pointer;
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typedef T& reference;
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typedef const T& const_reference;
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typedef T value_type;
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template <class T1> struct rebind {
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typedef STL_Allocator<T1, Alloc> other;
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};
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STL_Allocator() { }
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STL_Allocator(const STL_Allocator&) { }
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template <class T1> STL_Allocator(const STL_Allocator<T1, Alloc>&) { }
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~STL_Allocator() { }
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pointer address(reference x) const { return &x; }
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const_pointer address(const_reference x) const { return &x; }
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pointer allocate(size_type n, const void* = 0) {
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RAW_DCHECK((n * sizeof(T)) / sizeof(T) == n, "n is too big to allocate");
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return static_cast<T*>(Alloc::Allocate(n * sizeof(T)));
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}
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void deallocate(pointer p, size_type n) { Alloc::Free(p, n * sizeof(T)); }
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size_type max_size() const { return size_t(-1) / sizeof(T); }
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void construct(pointer p, const T& val) { ::new(p) T(val); }
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void construct(pointer p) { ::new(p) T(); }
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void destroy(pointer p) { p->~T(); }
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// There's no state, so these allocators are always equal
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bool operator==(const STL_Allocator&) const { return true; }
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};
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#endif // BASE_STL_ALLOCATOR_H_
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