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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
#ifndef PALLOC_ALLOCATOR_H
#define PALLOC_ALLOCATOR_H
// these extern declarations are to avoid including postgres.h in C++ code
extern "C" {
extern void *palloc(unsigned long long size);
extern void pfree(void *pointer);
}
#include <new>
#include <utility>
template <class T> class palloc_allocator {
public:
typedef T value_type;
typedef value_type* pointer;
typedef const value_type* const_pointer;
typedef value_type& reference;
typedef const value_type& const_reference;
typedef std::size_t size_type;
typedef std::ptrdiff_t difference_type;
template <class U>
struct rebind { typedef palloc_allocator<U> other; };
palloc_allocator() = default;
template <class U>
palloc_allocator(const palloc_allocator<U>&) {}
pointer address(reference x) const { return &x; }
const_pointer address(const_reference x) const {
return &x;
}
pointer allocate(size_type n, const_pointer = 0) {
void* p = palloc(n * sizeof(T));
if (!p) throw std::bad_alloc();
return static_cast<pointer>(p);
}
void deallocate(pointer p, size_type) { if (p) pfree(p); }
size_type max_size() const {
return static_cast<size_type>(-1) / sizeof(T);
}
template<typename... Args>
void construct(pointer p, Args&&... args) {
new(p) value_type(std::forward<Args>(args)...);
}
void destroy(pointer p) { p->~value_type(); }
};
template<> class palloc_allocator<void> {
public:
typedef void value_type;
typedef void* pointer;
typedef const void* const_pointer;
template <class U>
struct rebind { typedef palloc_allocator<U> other; };
};
template <class T>
inline bool operator==(const palloc_allocator<T>&, const palloc_allocator<T>&) {
return true;
}
template <class T>
inline bool operator!=(const palloc_allocator<T>&, const palloc_allocator<T>&) {
return false;
}
#endif