path: root/misc.h

#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)
{
#ifdef PPC_INTRINSICS
	// PPC: load reverse indexed instruction
	return (word32)__lwbrx(&value,0);
#elif defined(FAST_ROTATE)
	// 5 instructions with rotate instruction, 9 without
	return (rotrFixed(value, 8U) & 0xff00ff00) | (rotlFixed(value, 8U) & 0x00ff00ff);
#else
	// 6 instructions with rotate instruction, 8 without
	value = ((value & 0xFF00FF00) >> 8) | ((value & 0x00FF00FF) << 8);
	return rotlFixed(value, 16U);
#endif
}

#ifdef WORD64_AVAILABLE
inline word64 ByteReverse(word64 value)
{
#ifdef SLOW_WORD64
	return (word64(ByteReverse(word32(value))) << 32) | ByteReverse(word32(value>>32));
#else
	value = ((value & W64LIT(0xFF00FF00FF00FF00)) >> 8) | ((value & W64LIT(0x00FF00FF00FF00FF)) << 8);
	value = ((value & W64LIT(0xFFFF0000FFFF0000)) >> 16) | ((value & W64LIT(0x0000FFFF0000FFFF)) << 16);
	return rotlFixed(value, 32U);
#endif
}
#endif

inline byte BitReverse(byte value)
{
	value = ((value & 0xAA) >> 1) | ((value & 0x55) << 1);
	value = ((value & 0xCC) >> 2) | ((value & 0x33) << 2);
	return rotlFixed(value, 4);
}

inline word16 BitReverse(word16 value)
{
	value = ((value & 0xAAAA) >> 1) | ((value & 0x5555) << 1);
	value = ((value & 0xCCCC) >> 2) | ((value & 0x3333) << 2);
	value = ((value & 0xF0F0) >> 4) | ((value & 0x0F0F) << 4);
	return ByteReverse(value);
}

inline word32 BitReverse(word32 value)
{
	value = ((value & 0xAAAAAAAA) >> 1) | ((value & 0x55555555) << 1);
	value = ((value & 0xCCCCCCCC) >> 2) | ((value & 0x33333333) << 2);
	value = ((value & 0xF0F0F0F0) >> 4) | ((value & 0x0F0F0F0F) << 4);
	return ByteReverse(value);
}

#ifdef WORD64_AVAILABLE
inline word64 BitReverse(word64 value)
{
#ifdef SLOW_WORD64
	return (word64(BitReverse(word32(value))) << 32) | BitReverse(word32(value>>32));
#else
	value = ((value & W64LIT(0xAAAAAAAAAAAAAAAA)) >> 1) | ((value & W64LIT(0x5555555555555555)) << 1);
	value = ((value & W64LIT(0xCCCCCCCCCCCCCCCC)) >> 2) | ((value & W64LIT(0x3333333333333333)) << 2);
	value = ((value & W64LIT(0xF0F0F0F0F0F0F0F0)) >> 4) | ((value & W64LIT(0x0F0F0F0F0F0F0F0F)) << 4);
	return ByteReverse(value);
#endif
}
#endif

template <class T>
inline T BitReverse(T value)
{
	if (sizeof(T) == 1)
		return (T)BitReverse((byte)value);
	else if (sizeof(T) == 2)
		return (T)BitReverse((word16)value);
	else if (sizeof(T) == 4)
		return (T)BitReverse((word32)value);
	else
	{
#ifdef WORD64_AVAILABLE
		assert(sizeof(T) == 8);
		return (T)BitReverse((word64)value);
#else
		assert(false);
		return 0;
#endif
	}
}

template <class T>
inline T ConditionalByteReverse(ByteOrder order, T value)
{
	return NativeByteOrderIs(order) ? value : ByteReverse(value);
}

template <class T>
void ByteReverse(T *out, const T *in, unsigned int byteCount)
{
	assert(byteCount % sizeof(T) == 0);
	unsigned int count = byteCount/sizeof(T);
	for (unsigned int i=0; i<count; i++)
		out[i] = ByteReverse(in[i]);
}

template <class T>
inline void ConditionalByteReverse(ByteOrder order, T *out, const T *in, unsigned int byteCount)
{
	if (!NativeByteOrderIs(order))
		ByteReverse(out, in, byteCount);
	else if (in != out)
		memcpy(out, in, byteCount);
}

template <class T>
inline void GetUserKey(ByteOrder order, T *out, unsigned int outlen, const byte *in, unsigned int inlen)
{
	const unsigned int U = sizeof(T);
	assert(inlen <= outlen*U);
	memcpy(out, in, inlen);
	memset((byte *)out+inlen, 0, outlen*U-inlen);
	ConditionalByteReverse(order, out, out, RoundUpToMultipleOf(inlen, U));
}

inline byte UnalignedGetWordNonTemplate(ByteOrder order, const byte *block, byte*)
{
	return block[0];
}

inline word16 UnalignedGetWordNonTemplate(ByteOrder order, const byte *block, word16*)
{
	return (order == BIG_ENDIAN_ORDER)
		? block[1] | (block[0] << 8)
		: block[0] | (block[1] << 8);
}

inline word32 UnalignedGetWordNonTemplate(ByteOrder order, const byte *block, word32*)
{
	return (order == BIG_ENDIAN_ORDER)
		? word32(block[3]) | (word32(block[2]) << 8) | (word32(block[1]) << 16) | (word32(block[0]) << 24)
		: word32(block[0]) | (word32(block[1]) << 8) | (word32(block[2]) << 16) | (word32(block[3]) << 24);
}

#ifdef WORD64_AVAILABLE
inline word64 UnalignedGetWordNonTemplate(ByteOrder order, const byte *block, word64*)
{
	return (order == BIG_ENDIAN_ORDER)
		?
		(word64(block[7]) |
		(word64(block[6]) <<  8) |
		(word64(block[5]) << 16) |
		(word64(block[4]) << 24) |
		(word64(block[3]) << 32) |
		(word64(block[2]) << 40) |
		(word64(block[1]) << 48) |
		(word64(block[0]) << 56))
		:
		(word64(block[0]) |
		(word64(block[1]) <<  8) |
		(word64(block[2]) << 16) |
		(word64(block[3]) << 24) |
		(word64(block[4]) << 32) |
		(word64(block[5]) << 40) |
		(word64(block[6]) << 48) |
		(word64(block[7]) << 56));
}
#endif

template <class T>
inline T UnalignedGetWord(ByteOrder order, const byte *block, T*dummy=NULL)
{
	return UnalignedGetWordNonTemplate(order, block, dummy);
}

inline void UnalignedPutWord(ByteOrder order, byte *block, byte value, const byte *xorBlock = NULL)
{
	block[0] = xorBlock ? (value ^ xorBlock[0]) : value;
}

inline void UnalignedPutWord(ByteOrder order, byte *block, word16 value, const byte *xorBlock = NULL)
{
	if (order == BIG_ENDIAN_ORDER)
	{
		block[0] = GETBYTE(value, 1);
		block[1] = GETBYTE(value, 0);
	}
	else
	{
		block[0] = GETBYTE(value, 0);
		block[1] = GETBYTE(value, 1);
	}

	if (xorBlock)
	{
		block[0] ^= xorBlock[0];
		block[1] ^= xorBlock[1];
	}
}

inline void UnalignedPutWord(ByteOrder order, byte *block, word32 value, const byte *xorBlock = NULL)
{
	if (order == BIG_ENDIAN_ORDER)
	{
		block[0] = GETBYTE(value, 3);
		block[1] = GETBYTE(value, 2);
		block[2] = GETBYTE(value, 1);
		block[3] = GETBYTE(value, 0);
	}
	else
	{
		block[0] = GETBYTE(value, 0);
		block[1] = GETBYTE(value, 1);
		block[2] = GETBYTE(value, 2);
		block[3] = GETBYTE(value, 3);
	}

	if (xorBlock)
	{
		block[0] ^= xorBlock[0];
		block[1] ^= xorBlock[1];
		block[2] ^= xorBlock[2];
		block[3] ^= xorBlock[3];
	}
}

#ifdef WORD64_AVAILABLE
inline void UnalignedPutWord(ByteOrder order, byte *block, word64 value, const byte *xorBlock = NULL)
{
	if (order == BIG_ENDIAN_ORDER)
	{
		block[0] = GETBYTE(value, 7);
		block[1] = GETBYTE(value, 6);
		block[2] = GETBYTE(value, 5);
		block[3] = GETBYTE(value, 4);
		block[4] = GETBYTE(value, 3);
		block[5] = GETBYTE(value, 2);
		block[6] = GETBYTE(value, 1);
		block[7] = GETBYTE(value, 0);
	}
	else
	{
		block[0] = GETBYTE(value, 0);
		block[1] = GETBYTE(value, 1);
		block[2] = GETBYTE(value, 2);
		block[3] = GETBYTE(value, 3);
		block[4] = GETBYTE(value, 4);
		block[5] = GETBYTE(value, 5);
		block[6] = GETBYTE(value, 6);
		block[7] = GETBYTE(value, 7);
	}

	if (xorBlock)
	{
		block[0] ^= xorBlock[0];
		block[1] ^= xorBlock[1];
		block[2] ^= xorBlock[2];
		block[3] ^= xorBlock[3];
		block[4] ^= xorBlock[4];
		block[5] ^= xorBlock[5];
		block[6] ^= xorBlock[6];
		block[7] ^= xorBlock[7];
	}
}
#endif

template <class T>
inline T GetWord(bool assumeAligned, ByteOrder order, const byte *block)
{
	if (assumeAligned)
	{
		assert(IsAligned<T>(block));
		return ConditionalByteReverse(order, *reinterpret_cast<const T *>(block));
	}
	else
		return UnalignedGetWord<T>(order, block);
}

template <class T>
inline void GetWord(bool assumeAligned, ByteOrder order, T &result, const byte *block)
{
	result = GetWord<T>(assumeAligned, order, block);
}

template <class T>
inline void PutWord(bool assumeAligned, ByteOrder order, byte *block, T value, const byte *xorBlock = NULL)
{
	if (assumeAligned)
	{
		assert(IsAligned<T>(block));
		if (xorBlock)
			*reinterpret_cast<T *>(block) = ConditionalByteReverse(order, value) ^ *reinterpret_cast<const T *>(xorBlock);
		else
			*reinterpret_cast<T *>(block) = ConditionalByteReverse(order, value);
	}
	else
		UnalignedPutWord(order, block, value, xorBlock);
}

template <class T, class B, bool A=true>
class GetBlock
{
public:
	GetBlock(const void *block)
		: m_block((const byte *)block) {}

	template <class U>
	inline GetBlock<T, B, A> & operator()(U &x)
	{
		CRYPTOPP_COMPILE_ASSERT(sizeof(U) >= sizeof(T));
		x = GetWord<T>(A, B::ToEnum(), m_block);
		m_block += sizeof(T);
		return *this;
	}

private:
	const byte *m_block;
};

template <class T, class B, bool A=true>
class PutBlock
{
public:
	PutBlock(const void *xorBlock, void *block)
		: m_xorBlock((const byte *)xorBlock), m_block((byte *)block) {}

	template <class U>
	inline PutBlock<T, B, A> & operator()(U x)
	{
		PutWord(A, B::ToEnum(), m_block, (T)x, m_xorBlock);
		m_block += sizeof(T);
		if (m_xorBlock)
			m_xorBlock += sizeof(T);
		return *this;
	}

private:
	const byte *m_xorBlock;
	byte *m_block;
};

template <class T, class B, bool A=true>
struct BlockGetAndPut
{
	// function needed because of C++ grammatical ambiguity between expression-statements and declarations
	static inline GetBlock<T, B, A> Get(const void *block) {return GetBlock<T, B, A>(block);}
	typedef PutBlock<T, B, A> Put;
};

template <class T>
std::string WordToString(T value, ByteOrder order = BIG_ENDIAN_ORDER)
{
	if (!NativeByteOrderIs(order))
		value = ByteReverse(value);

	return std::string((char *)&value, sizeof(value));
}

template <class T>
T StringToWord(const std::string &str, ByteOrder order = BIG_ENDIAN_ORDER)
{
	T value = 0;
	memcpy(&value, str.data(), STDMIN(sizeof(value), str.size()));
	return NativeByteOrderIs(order) ? value : ByteReverse(value);
}

// ************** help remove warning on g++ ***************

template <bool overflow> struct SafeShifter;

template<> struct SafeShifter<true>
{
	template <class T>
	static inline T RightShift(T value, unsigned int bits)
	{
		return 0;
	}

	template <class T>
	static inline T LeftShift(T value, unsigned int bits)
	{
		return 0;
	}
};

template<> struct SafeShifter<false>
{
	template <class T>
	static inline T RightShift(T value, unsigned int bits)
	{
		return value >> bits;
	}

	template <class T>
	static inline T LeftShift(T value, unsigned int bits)
	{
		return value << bits;
	}
};

template <unsigned int bits, class T>
inline T SafeRightShift(T value)
{
	return SafeShifter<(bits>=(8*sizeof(T)))>::RightShift(value, bits);
}

template <unsigned int bits, class T>
inline T SafeLeftShift(T value)
{
	return SafeShifter<(bits>=(8*sizeof(T)))>::LeftShift(value, bits);
}

NAMESPACE_END

#endif // MISC_H