1 // Copyright (c) 2009-2010 Satoshi Nakamoto
2 // Copyright (c) 2009-2012 The Bitcoin developers
3 // Distributed under the MIT/X11 software license, see the accompanying
4 // file license.txt or http://www.opensource.org/licenses/mit-license.php.
5 #ifndef BITCOIN_ALLOCATORS_H
6 #define BITCOIN_ALLOCATORS_H
11 #define _WIN32_WINNT 0x0501
12 #define WIN32_LEAN_AND_MEAN 1
17 // This is used to attempt to keep keying material out of swap
18 // Note that VirtualLock does not provide this as a guarantee on Windows,
19 // but, in practice, memory that has been VirtualLock'd almost never gets written to
20 // the pagefile except in rare circumstances where memory is extremely low.
21 #define mlock(p, n) VirtualLock((p), (n));
22 #define munlock(p, n) VirtualUnlock((p), (n));
26 /* This comes from limits.h if it's not defined there set a sane default */
29 #define PAGESIZE sysconf(_SC_PAGESIZE)
32 mlock(((void *)(((size_t)(a)) & (~((PAGESIZE)-1)))),\
33 (((((size_t)(a)) + (b) - 1) | ((PAGESIZE) - 1)) + 1) - (((size_t)(a)) & (~((PAGESIZE) - 1))))
34 #define munlock(a,b) \
35 munlock(((void *)(((size_t)(a)) & (~((PAGESIZE)-1)))),\
36 (((((size_t)(a)) + (b) - 1) | ((PAGESIZE) - 1)) + 1) - (((size_t)(a)) & (~((PAGESIZE) - 1))))
40 // Allocator that locks its contents from being paged
41 // out of memory and clears its contents before deletion.
44 struct secure_allocator : public std::allocator<T>
46 // MSVC8 default copy constructor is broken
47 typedef std::allocator<T> base;
48 typedef typename base::size_type size_type;
49 typedef typename base::difference_type difference_type;
50 typedef typename base::pointer pointer;
51 typedef typename base::const_pointer const_pointer;
52 typedef typename base::reference reference;
53 typedef typename base::const_reference const_reference;
54 typedef typename base::value_type value_type;
55 secure_allocator() throw() {}
56 secure_allocator(const secure_allocator& a) throw() : base(a) {}
58 secure_allocator(const secure_allocator<U>& a) throw() : base(a) {}
59 ~secure_allocator() throw() {}
60 template<typename _Other> struct rebind
61 { typedef secure_allocator<_Other> other; };
63 T* allocate(std::size_t n, const void *hint = 0)
66 p = std::allocator<T>::allocate(n, hint);
68 mlock(p, sizeof(T) * n);
72 void deallocate(T* p, std::size_t n)
76 memset(p, 0, sizeof(T) * n);
77 munlock(p, sizeof(T) * n);
79 std::allocator<T>::deallocate(p, n);
85 // Allocator that clears its contents before deletion.
88 struct zero_after_free_allocator : public std::allocator<T>
90 // MSVC8 default copy constructor is broken
91 typedef std::allocator<T> base;
92 typedef typename base::size_type size_type;
93 typedef typename base::difference_type difference_type;
94 typedef typename base::pointer pointer;
95 typedef typename base::const_pointer const_pointer;
96 typedef typename base::reference reference;
97 typedef typename base::const_reference const_reference;
98 typedef typename base::value_type value_type;
99 zero_after_free_allocator() throw() {}
100 zero_after_free_allocator(const zero_after_free_allocator& a) throw() : base(a) {}
101 template <typename U>
102 zero_after_free_allocator(const zero_after_free_allocator<U>& a) throw() : base(a) {}
103 ~zero_after_free_allocator() throw() {}
104 template<typename _Other> struct rebind
105 { typedef zero_after_free_allocator<_Other> other; };
107 void deallocate(T* p, std::size_t n)
110 memset(p, 0, sizeof(T) * n);
111 std::allocator<T>::deallocate(p, n);
115 // This is exactly like std::string, but with a custom allocator.
116 // (secure_allocator<> is defined in serialize.h)
117 typedef std::basic_string<char, std::char_traits<char>, secure_allocator<char> > SecureString;