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
15 #define _WIN32_WINNT 0x0501
16 #define WIN32_LEAN_AND_MEAN 1
21 // This is used to attempt to keep keying material out of swap
22 // Note that VirtualLock does not provide this as a guarantee on Windows,
23 // but, in practice, memory that has been VirtualLock'd almost never gets written to
24 // the pagefile except in rare circumstances where memory is extremely low.
25 #define mlock(p, n) VirtualLock((p), (n));
26 #define munlock(p, n) VirtualUnlock((p), (n));
30 /* This comes from limits.h if it's not defined there set a sane default */
33 #define PAGESIZE sysconf(_SC_PAGESIZE)
36 mlock(((void *)(((size_t)(a)) & (~((PAGESIZE)-1)))),\
37 (((((size_t)(a)) + (b) - 1) | ((PAGESIZE) - 1)) + 1) - (((size_t)(a)) & (~((PAGESIZE) - 1))))
38 #define munlock(a,b) \
39 munlock(((void *)(((size_t)(a)) & (~((PAGESIZE)-1)))),\
40 (((((size_t)(a)) + (b) - 1) | ((PAGESIZE) - 1)) + 1) - (((size_t)(a)) & (~((PAGESIZE) - 1))))
44 // Allocator that locks its contents from being paged
45 // out of memory and clears its contents before deletion.
48 struct secure_allocator : public std::allocator<T>
50 // MSVC8 default copy constructor is broken
51 typedef std::allocator<T> base;
52 typedef typename base::size_type size_type;
53 typedef typename base::difference_type difference_type;
54 typedef typename base::pointer pointer;
55 typedef typename base::const_pointer const_pointer;
56 typedef typename base::reference reference;
57 typedef typename base::const_reference const_reference;
58 typedef typename base::value_type value_type;
59 secure_allocator() throw() {}
60 secure_allocator(const secure_allocator& a) throw() : base(a) {}
62 secure_allocator(const secure_allocator<U>& a) throw() : base(a) {}
63 ~secure_allocator() throw() {}
64 template<typename _Other> struct rebind
65 { typedef secure_allocator<_Other> other; };
67 T* allocate(std::size_t n, const void *hint = 0)
70 p = std::allocator<T>::allocate(n, hint);
72 mlock(p, sizeof(T) * n);
76 void deallocate(T* p, std::size_t n)
80 memset(p, 0, sizeof(T) * n);
81 munlock(p, sizeof(T) * n);
83 std::allocator<T>::deallocate(p, n);
89 // Allocator that clears its contents before deletion.
92 struct zero_after_free_allocator : public std::allocator<T>
94 // MSVC8 default copy constructor is broken
95 typedef std::allocator<T> base;
96 typedef typename base::size_type size_type;
97 typedef typename base::difference_type difference_type;
98 typedef typename base::pointer pointer;
99 typedef typename base::const_pointer const_pointer;
100 typedef typename base::reference reference;
101 typedef typename base::const_reference const_reference;
102 typedef typename base::value_type value_type;
103 zero_after_free_allocator() throw() {}
104 zero_after_free_allocator(const zero_after_free_allocator& a) throw() : base(a) {}
105 template <typename U>
106 zero_after_free_allocator(const zero_after_free_allocator<U>& a) throw() : base(a) {}
107 ~zero_after_free_allocator() throw() {}
108 template<typename _Other> struct rebind
109 { typedef zero_after_free_allocator<_Other> other; };
111 void deallocate(T* p, std::size_t n)
114 memset(p, 0, sizeof(T) * n);
115 std::allocator<T>::deallocate(p, n);
119 // This is exactly like std::string, but with a custom allocator.
120 // (secure_allocator<> is defined in serialize.h)
121 typedef std::basic_string<char, std::char_traits<char>, secure_allocator<char> > SecureString;