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