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/*************************************************
* Bit/Word Operations Header File *
* (C) 1999-2008 Jack Lloyd *
*************************************************/
#ifndef BOTAN_BIT_OPS_H__
#define BOTAN_BIT_OPS_H__
#include <botan/types.h>
namespace Botan {
/*************************************************
* Word Rotation Functions *
*************************************************/
template<typename T> inline T rotate_left(T input, u32bit rot)
{
return static_cast<T>((input << rot) | (input >> (8*sizeof(T)-rot)));;
}
template<typename T> inline T rotate_right(T input, u32bit rot)
{
return static_cast<T>((input >> rot) | (input << (8*sizeof(T)-rot)));
}
/*************************************************
* Byte Swapping Functions *
*************************************************/
inline u16bit reverse_bytes(u16bit input)
{
return rotate_left(input, 8);
}
inline u32bit reverse_bytes(u32bit input)
{
asm("bswapl %0" : "=r" (input) : "0" (input));
return input;
}
inline u64bit reverse_bytes(u64bit input)
{
asm("bswapq %0" : "=r" (input) : "0" (input));
return input;
}
/*************************************************
* XOR Arrays *
*************************************************/
inline void xor_buf(byte out[], const byte in[], u32bit length)
{
while(length >= 8)
{
*reinterpret_cast<u64bit*>(out) ^= *reinterpret_cast<const u64bit*>(in);
in += 8; out += 8; length -= 8;
}
for(u32bit j = 0; j != length; ++j)
out[j] ^= in[j];
}
/*************************************************
* XOR Arrays *
*************************************************/
inline void xor_buf(byte out[], const byte in[],
const byte in2[], u32bit length)
{
while(length >= 8)
{
*reinterpret_cast<u64bit*>(out) =
*reinterpret_cast<const u64bit*>(in) ^
*reinterpret_cast<const u64bit*>(in2);
in += 8; in2 += 8; out += 8; length -= 8;
}
for(u32bit j = 0; j != length; ++j)
out[j] = in[j] ^ in2[j];
}
/*************************************************
* Simple Bit Manipulation *
*************************************************/
bool power_of_2(u64bit);
u32bit high_bit(u64bit);
u32bit low_bit(u64bit);
u32bit significant_bytes(u64bit);
u32bit hamming_weight(u64bit);
}
#endif
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