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/*
* Author: Sven Gothel <sgothel@jausoft.com>
* Copyright (c) 2021 Gothel Software e.K.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef C_ALLOCATOR_HPP
#define C_ALLOCATOR_HPP
#include <cinttypes>
#include <memory>
#include <jau/basic_types.hpp>
namespace jau {
/**
* A simple allocator using POSIX C functions: <code>::malloc()</code>, <code>::free()</code> and <code>::realloc()</code>.<br>
* It is the missing <code>::realloc()</code> in <code>std::allocator</code>, motivating this class.<br>
* Since <code>realloc()</code> requires the passed pointer to originate from <code>malloc()</code> or <code>calloc</code>,
* we have to use it for <code>allocate()</code> as well.
*
* Added method is <code>reallocate()</code> using the native <code>realloc()</code>.
*
* This class shall be compliant with <i>C++ named requirements for Allocator</i>.
*
* Not implementing deprecated (C++17) and removed (C++20)
* methods: address(), max_size(), construct() and destroy().
*/
template <class T>
struct callocator
{
public:
// typedefs' for C++ named requirements: Allocator
typedef T value_type;
typedef std::size_t size_type;
typedef std::ptrdiff_t difference_type;
typedef std::true_type propagate_on_container_move_assignment;
// C++17, deprecated in C++20
typedef std::true_type is_always_equal;
// deprecated in C++17 and removed in C++20
typedef T* pointer;
typedef const T* const_pointer;
typedef T& reference;
typedef const T& const_reference;
template <class U> struct rebind {typedef callocator<U> other;};
private:
typedef std::remove_const_t<T> value_type_mutable;
/** Required to create and move immutable elements, aka const */
typedef value_type_mutable* pointer_mutable;
public:
callocator() noexcept
{ } // C++11
#if __cplusplus > 201703L
constexpr callocator(const callocator& other) noexcept
{} // C++20
#else
callocator(const callocator& other) noexcept
{ (void)other; }
#endif
#if __cplusplus > 201703L
template <typename U>
constexpr callocator(const callocator<U>& other) noexcept
{ (void)other; } // C++20
#else
template <typename U>
callocator(const callocator<U>& other) noexcept
{ (void)other; }
#endif
#if __cplusplus > 201703L
constexpr ~callocator() {} // C++20
#else
~callocator() {}
#endif
#if __cplusplus <= 201703L
value_type* allocate(std::size_t n, const void * hint) { // C++17 deprecated; C++20 removed
(void)hint;
return reinterpret_cast<value_type*>( ::malloc( n * sizeof(value_type) ) );
}
#endif
#if __cplusplus > 201703L
[[nodiscard]] constexpr value_type* allocate(std::size_t n) { // C++20
return reinterpret_cast<value_type*>( malloc( n * sizeof(value_type) ) );
}
#else
value_type* allocate(std::size_t n) { // C++17
return reinterpret_cast<value_type*>( ::malloc( n * sizeof(value_type) ) );
}
#endif
[[nodiscard]] constexpr value_type* reallocate(value_type* p, std::size_t old_size, std::size_t new_size) {
(void)old_size;
return reinterpret_cast<value_type*>(
::realloc( reinterpret_cast<void*>(const_cast<pointer_mutable>(p)), new_size * sizeof(value_type) ) );
}
#if __cplusplus > 201703L
constexpr void deallocate(value_type* p, std::size_t n ) {
(void)n;
free( reinterpret_cast<void*>( p ) );
}
#else
void deallocate(value_type* p, std::size_t n ) {
(void)n;
::free( reinterpret_cast<void*>( const_cast<pointer_mutable>(p) ) );
}
#endif
};
#if __cplusplus > 201703L
template <class T1, class T2>
constexpr bool operator==(const callocator<T1>& lhs, const callocator<T2>& rhs) noexcept {
#if 0
if( &lhs == &rhs ) {
return true;
}
return lhs.memory_usage == rhs.memory_usage;
#else
(void)lhs;
(void)rhs;
return true;
#endif
}
#else
template <class T1, class T2>
bool operator==(const callocator<T1>& lhs, const callocator<T2>& rhs) noexcept {
#if 0
if( &lhs == &rhs ) {
return true;
}
return lhs.memory_usage == rhs.memory_usage;
#else
(void)lhs;
(void)rhs;
return true;
#endif
}
template <class T1, class T2>
bool operator!=(const callocator<T1>& lhs, const callocator<T2>& rhs) noexcept {
return !(lhs==rhs);
}
#endif
} /* namespace jau */
#endif // TEST_ALLOCATOR_HPP
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