misc.h

加密函数库:包括多种加密解密算法,数字签名,散列算法

#ifndef CRYPTOPP_MISC_H
#define CRYPTOPP_MISC_H

#include "config.h"
#include "cryptlib.h"
#include <assert.h>
#include <string.h>		// CodeWarrior doesn't have memory.h
#include <algorithm>
#include <string>

#ifdef INTEL_INTRINSICS
#include <stdlib.h>
#endif

NAMESPACE_BEGIN(CryptoPP)

// ************** compile-time assertion ***************

template <bool b>
struct CompileAssert
{
	static char dummy[2*b-1];
};

#define CRYPTOPP_COMPILE_ASSERT(assertion) CRYPTOPP_COMPILE_ASSERT_INSTANCE(assertion, __LINE__)
#define CRYPTOPP_COMPILE_ASSERT_INSTANCE(assertion, instance) static CompileAssert<(assertion)> CRYPTOPP_ASSERT_JOIN(cryptopp_assert_, instance)
#define CRYPTOPP_ASSERT_JOIN(X, Y) CRYPTOPP_DO_ASSERT_JOIN(X, Y)
#define CRYPTOPP_DO_ASSERT_JOIN(X, Y) X##Y

// ************** misc classes ***************

class Empty
{
};

template <class BASE1, class BASE2>
class TwoBases : public BASE1, public BASE2
{
};

template <class BASE1, class BASE2, class BASE3>
class ThreeBases : public BASE1, public BASE2, public BASE3
{
};

template <class T>
class ObjectHolder
{
protected:
	T m_object;
};

class NotCopyable
{
public:
	NotCopyable() {}
private:
    NotCopyable(const NotCopyable &);
    void operator=(const NotCopyable &);
};

// ************** misc functions ***************

// can't use std::min or std::max in MSVC60 or Cygwin 1.1.0
template <class _Tp> inline const _Tp& STDMIN(const _Tp& __a, const _Tp& __b)
{
	return __b < __a ? __b : __a;
}

template <class _Tp> inline const _Tp& STDMAX(const _Tp& __a, const _Tp& __b)
{
	return  __a < __b ? __b : __a;
}

#define RETURN_IF_NONZERO(x) unsigned int returnedValue = x; if (returnedValue) return returnedValue

// this version of the macro is fastest on Pentium 3 and Pentium 4 with MSVC 6 SP5 w/ Processor Pack
#define GETBYTE(x, y) (unsigned int)byte((x)>>(8*(y)))
// these may be faster on other CPUs/compilers
// #define GETBYTE(x, y) (unsigned int)(((x)>>(8*(y)))&255)
// #define GETBYTE(x, y) (((byte *)&(x))[y])

unsigned int Parity(unsigned long);
unsigned int BytePrecision(unsigned long);
unsigned int BitPrecision(unsigned long);
unsigned long Crop(unsigned long, unsigned int size);

inline unsigned int BitsToBytes(unsigned int bitCount)
{
	return ((bitCount+7)/(8));
}

inline unsigned int BytesToWords(unsigned int byteCount)
{
	return ((byteCount+WORD_SIZE-1)/WORD_SIZE);
}

inline unsigned int BitsToWords(unsigned int bitCount)
{
	return ((bitCount+WORD_BITS-1)/(WORD_BITS));
}

void xorbuf(byte *buf, const byte *mask, unsigned int count);
void xorbuf(byte *output, const byte *input, const byte *mask, unsigned int count);

template <class T>
inline bool IsPowerOf2(T n)
{
	return n > 0 && (n & (n-1)) == 0;
}

template <class T1, class T2>
inline T2 ModPowerOf2(T1 a, T2 b)
{
	assert(IsPowerOf2(b));
	return T2(a) & (b-1);
}

template <class T>
inline T RoundDownToMultipleOf(T n, T m)
{
	return n - (IsPowerOf2(m) ? ModPowerOf2(n, m) : (n%m));
}

template <class T>
inline T RoundUpToMultipleOf(T n, T m)
{
	return RoundDownToMultipleOf(n+m-1, m);
}

template <class T>
inline unsigned int GetAlignment(T *dummy=NULL)	// VC60 workaround
{
#if (_MSC_VER >= 1300)
	return __alignof(T);
#elif defined(__GNUC__)
	return __alignof__(T);
#else
	return sizeof(T);
#endif
}

inline bool IsAlignedOn(const void *p, unsigned int alignment)
{
	return IsPowerOf2(alignment) ? ModPowerOf2((unsigned int)p, alignment) == 0 : (unsigned int)p % alignment == 0;
}

template <class T>
inline bool IsAligned(const void *p, T *dummy=NULL)	// VC60 workaround
{
	return IsAlignedOn(p, GetAlignment<T>());
}

#ifdef IS_LITTLE_ENDIAN
	typedef LittleEndian NativeByteOrder;
#else
	typedef BigEndian NativeByteOrder;
#endif

inline ByteOrder GetNativeByteOrder()
{
	return NativeByteOrder::ToEnum();
}

inline bool NativeByteOrderIs(ByteOrder order)
{
	return order == GetNativeByteOrder();
}

template <class T>		// can't use <sstream> because GCC 2.95.2 doesn't have it
std::string IntToString(T a, unsigned int base = 10)
{
	if (a == 0)
		return "0";
	bool negate = false;
	if (a < 0)
	{
		negate = true;
		a = 0-a;	// VC .NET does not like -a
	}
	std::string result;
	while (a > 0)
	{
		T digit = a % base;
		result = char((digit < 10 ? '0' : ('a' - 10)) + digit) + result;
		a /= base;
	}
	if (negate)
		result = "-" + result;
	return result;
}

template <class T1, class T2>
inline T1 SaturatingSubtract(T1 a, T2 b)
{
	CRYPTOPP_COMPILE_ASSERT_INSTANCE(T1(-1)>0, 0);	// T1 is unsigned type
	CRYPTOPP_COMPILE_ASSERT_INSTANCE(T2(-1)>0, 1);	// T2 is unsigned type
	return T1((a > b) ? (a - b) : 0);
}

template <class T>
inline CipherDir GetCipherDir(const T &obj)
{
	return obj.IsForwardTransformation() ? ENCRYPTION : DECRYPTION;
}

// ************** rotate functions ***************

template <class T> inline T rotlFixed(T x, unsigned int y)
{
	assert(y < sizeof(T)*8);
	return (x<<y) | (x>>(sizeof(T)*8-y));
}

template <class T> inline T rotrFixed(T x, unsigned int y)
{
	assert(y < sizeof(T)*8);
	return (x>>y) | (x<<(sizeof(T)*8-y));
}

template <class T> inline T rotlVariable(T x, unsigned int y)
{
	assert(y < sizeof(T)*8);
	return (x<<y) | (x>>(sizeof(T)*8-y));
}

template <class T> inline T rotrVariable(T x, unsigned int y)
{
	assert(y < sizeof(T)*8);
	return (x>>y) | (x<<(sizeof(T)*8-y));
}

template <class T> inline T rotlMod(T x, unsigned int y)
{
	y %= sizeof(T)*8;
	return (x<<y) | (x>>(sizeof(T)*8-y));
}

template <class T> inline T rotrMod(T x, unsigned int y)
{
	y %= sizeof(T)*8;
	return (x>>y) | (x<<(sizeof(T)*8-y));
}

#ifdef INTEL_INTRINSICS

#pragma intrinsic(_lrotl, _lrotr)

template<> inline word32 rotlFixed<word32>(word32 x, unsigned int y)
{
	assert(y < 32);
	return y ? _lrotl(x, y) : x;
}

template<> inline word32 rotrFixed<word32>(word32 x, unsigned int y)
{
	assert(y < 32);
	return y ? _lrotr(x, y) : x;
}

template<> inline word32 rotlVariable<word32>(word32 x, unsigned int y)
{
	assert(y < 32);
	return _lrotl(x, y);
}

template<> inline word32 rotrVariable<word32>(word32 x, unsigned int y)
{
	assert(y < 32);
	return _lrotr(x, y);
}

template<> inline word32 rotlMod<word32>(word32 x, unsigned int y)
{
	return _lrotl(x, y);
}

template<> inline word32 rotrMod<word32>(word32 x, unsigned int y)
{
	return _lrotr(x, y);
}

#endif // #ifdef INTEL_INTRINSICS

#ifdef PPC_INTRINSICS

template<> inline word32 rotlFixed<word32>(word32 x, unsigned int y)
{
	assert(y < 32);
	return y ? __rlwinm(x,y,0,31) : x;
}

template<> inline word32 rotrFixed<word32>(word32 x, unsigned int y)
{
	assert(y < 32);
	return y ? __rlwinm(x,32-y,0,31) : x;
}

template<> inline word32 rotlVariable<word32>(word32 x, unsigned int y)
{
	assert(y < 32);
	return (__rlwnm(x,y,0,31));
}

template<> inline word32 rotrVariable<word32>(word32 x, unsigned int y)
{
	assert(y < 32);
	return (__rlwnm(x,32-y,0,31));
}

template<> inline word32 rotlMod<word32>(word32 x, unsigned int y)
{
	return (__rlwnm(x,y,0,31));
}

template<> inline word32 rotrMod<word32>(word32 x, unsigned int y)
{
	return (__rlwnm(x,32-y,0,31));
}

#endif // #ifdef PPC_INTRINSICS

// ************** endian reversal ***************

template <class T>
inline unsigned int GetByte(ByteOrder order, T value, unsigned int index)
{
	if (order == LITTLE_ENDIAN_ORDER)
		return GETBYTE(value, index);
	else
		return GETBYTE(value, sizeof(T)-index-1);
}

inline byte ByteReverse(byte value)
{
	return value;
}

inline word16 ByteReverse(word16 value)
{
	return rotlFixed(value, 8U);
}

inline word32 ByteReverse(word32 value)
{