zeroafterfree.h

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// Copyright (c) 2009-2010 Satoshi Nakamoto
// Copyright (c) 2009-2015 The Bitcoin Core developers
// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
#ifndef BITCOIN_SUPPORT_ALLOCATORS_ZEROAFTERFREE_H
#define BITCOIN_SUPPORT_ALLOCATORS_ZEROAFTERFREE_H
 
#include <support/cleanse.h>
 
#include <memory>
#include <vector>
 
template <typename T>
struct zero_after_free_allocator : public std::allocator<T> {
    // MSVC8 default copy constructor is broken
    typedef std::allocator<T> base;
    typedef typename base::size_type size_type;
    typedef typename base::difference_type difference_type;
    typedef typename base::pointer pointer;
    typedef typename base::const_pointer const_pointer;
    typedef typename base::reference reference;
    typedef typename base::const_reference const_reference;
    typedef typename base::value_type value_type;
    zero_after_free_allocator() noexcept {}
    zero_after_free_allocator(const zero_after_free_allocator &a) noexcept
        : base(a) {}
    template <typename U>
    zero_after_free_allocator(const zero_after_free_allocator<U> &a) noexcept
        : base(a) {}
    ~zero_after_free_allocator() noexcept {}
    template <typename _Other> struct rebind {
        typedef zero_after_free_allocator<_Other> other;
    };
 
    void deallocate(T *p, std::size_t n) {
        if (p != nullptr) memory_cleanse(p, sizeof(T) * n);
        std::allocator<T>::deallocate(p, n);
    }
};
 
// Byte-vector that clears its contents before deletion.
typedef std::vector<char, zero_after_free_allocator<char>> CSerializeData;
 
#endif // BITCOIN_SUPPORT_ALLOCATORS_ZEROAFTERFREE_H