1 /* Copyright (c) 2006, Google Inc. 2 * All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions are 6 * met: 7 * 8 * * Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * * Redistributions in binary form must reproduce the above 11 * copyright notice, this list of conditions and the following disclaimer 12 * in the documentation and/or other materials provided with the 13 * distribution. 14 * * Neither the name of Google Inc. nor the names of its 15 * contributors may be used to endorse or promote products derived from 16 * this software without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * --- 31 * Author: Maxim Lifantsev 32 */ 33 34 35 #ifndef BASE_STL_ALLOCATOR_H_ 36 #define BASE_STL_ALLOCATOR_H_ 37 38 #include <config.h> 39 40 #include <stddef.h> // for ptrdiff_t 41 #include <limits> 42 43 #include "base/logging.h" 44 45 // Generic allocator class for STL objects 46 // that uses a given type-less allocator Alloc, which must provide: 47 // static void* Alloc::Allocate(size_t size); 48 // static void Alloc::Free(void* ptr, size_t size); 49 // 50 // STL_Allocator<T, MyAlloc> provides the same thread-safety 51 // guarantees as MyAlloc. 52 // 53 // Usage example: 54 // set<T, less<T>, STL_Allocator<T, MyAlloc> > my_set; 55 // CAVEAT: Parts of the code below are probably specific 56 // to the STL version(s) we are using. 57 // The code is simply lifted from what std::allocator<> provides. 58 template <typename T, class Alloc> 59 class STL_Allocator { 60 public: 61 typedef size_t size_type; 62 typedef ptrdiff_t difference_type; 63 typedef T* pointer; 64 typedef const T* const_pointer; 65 typedef T& reference; 66 typedef const T& const_reference; 67 typedef T value_type; 68 69 template <class T1> struct rebind { 70 typedef STL_Allocator<T1, Alloc> other; 71 }; 72 73 STL_Allocator() { } 74 STL_Allocator(const STL_Allocator&) { } 75 template <class T1> STL_Allocator(const STL_Allocator<T1, Alloc>&) { } 76 ~STL_Allocator() { } 77 78 pointer address(reference x) const { return &x; } 79 const_pointer address(const_reference x) const { return &x; } 80 81 pointer allocate(size_type n, const void* = 0) { 82 RAW_DCHECK((n * sizeof(T)) / sizeof(T) == n, "n is too big to allocate"); 83 return static_cast<T*>(Alloc::Allocate(n * sizeof(T))); 84 } 85 void deallocate(pointer p, size_type n) { Alloc::Free(p, n * sizeof(T)); } 86 87 size_type max_size() const { return size_t(-1) / sizeof(T); } 88 89 void construct(pointer p, const T& val) { ::new(p) T(val); } 90 void construct(pointer p) { ::new(p) T(); } 91 void destroy(pointer p) { p->~T(); } 92 93 // There's no state, so these allocators are always equal 94 bool operator==(const STL_Allocator&) const { return true; } 95 }; 96 97 #endif // BASE_STL_ALLOCATOR_H_ 98
