Botan
1.11.15
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00001 /* 00002 * Memory Operations 00003 * (C) 1999-2009,2012 Jack Lloyd 00004 * 00005 * Botan is released under the Simplified BSD License (see license.txt) 00006 */ 00007 00008 #ifndef BOTAN_MEMORY_OPS_H__ 00009 #define BOTAN_MEMORY_OPS_H__ 00010 00011 #include <botan/types.h> 00012 #include <cstring> 00013 00014 namespace Botan { 00015 00016 /** 00017 * Zeroize memory 00018 * @param ptr a pointer to memory to zero out 00019 * @param n the number of bytes pointed to by ptr 00020 */ 00021 BOTAN_DLL void zero_mem(void* ptr, size_t n); 00022 00023 /** 00024 * Zeroize memory 00025 * @param ptr a pointer to an array 00026 * @param n the number of Ts pointed to by ptr 00027 */ 00028 template<typename T> inline void clear_mem(T* ptr, size_t n) 00029 { 00030 std::memset(ptr, 0, sizeof(T)*n); 00031 } 00032 00033 /** 00034 * Copy memory 00035 * @param out the destination array 00036 * @param in the source array 00037 * @param n the number of elements of in/out 00038 */ 00039 template<typename T> inline void copy_mem(T* out, const T* in, size_t n) 00040 { 00041 std::memmove(out, in, sizeof(T)*n); 00042 } 00043 00044 /** 00045 * Set memory to a fixed value 00046 * @param ptr a pointer to an array 00047 * @param n the number of Ts pointed to by ptr 00048 * @param val the value to set each byte to 00049 */ 00050 template<typename T> 00051 inline void set_mem(T* ptr, size_t n, byte val) 00052 { 00053 std::memset(ptr, val, sizeof(T)*n); 00054 } 00055 00056 /** 00057 * Memory comparison, input insensitive 00058 * @param p1 a pointer to an array 00059 * @param p2 a pointer to another array 00060 * @param n the number of Ts in p1 and p2 00061 * @return true iff p1[i] == p2[i] forall i in [0...n) 00062 */ 00063 template<typename T> inline bool same_mem(const T* p1, const T* p2, size_t n) 00064 { 00065 volatile T difference = 0; 00066 00067 for(size_t i = 0; i != n; ++i) 00068 difference |= (p1[i] ^ p2[i]); 00069 00070 return difference == 0; 00071 } 00072 00073 } 00074 00075 #endif