/*************************************************
* 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)
   {
   input = ((input & 0xFF00FF00) >> 8) | ((input & 0x00FF00FF) << 8);
   return rotate_left(input, 16);
   }

inline u64bit reverse_bytes(u64bit input)
   {
   u32bit hi = ((input >> 40) & 0x00FF00FF) | ((input >> 24) & 0xFF00FF00);
   u32bit lo = ((input & 0xFF00FF00) >> 8) | ((input & 0x00FF00FF) << 8);
   hi = (hi << 16) | (hi >> 16);
   lo = (lo << 16) | (lo >> 16);
   return (static_cast<u64bit>(lo) << 32) | hi;
   }

/*************************************************
* XOR Arrays                                     *
*************************************************/
inline void xor_buf(byte data[], const byte mask[], u32bit length)
   {
   while(length >= 8)
      {
      data[0] ^= mask[0]; data[1] ^= mask[1];
      data[2] ^= mask[2]; data[3] ^= mask[3];
      data[4] ^= mask[4]; data[5] ^= mask[5];
      data[6] ^= mask[6]; data[7] ^= mask[7];
      data += 8; mask += 8; length -= 8;
      }
   for(u32bit j = 0; j != length; ++j)
      data[j] ^= mask[j];
   }

/*************************************************
* XOR Arrays                                     *
*************************************************/
inline void xor_buf(byte out[], const byte in[],
                    const byte mask[], u32bit length)
   {
   while(length >= 8)
      {
      out[0] = in[0] ^ mask[0]; out[1] = in[1] ^ mask[1];
      out[2] = in[2] ^ mask[2]; out[3] = in[3] ^ mask[3];
      out[4] = in[4] ^ mask[4]; out[5] = in[5] ^ mask[5];
      out[6] = in[6] ^ mask[6]; out[7] = in[7] ^ mask[7];
      in += 8; out += 8; mask += 8; length -= 8;
      }
   for(u32bit j = 0; j != length; ++j)
      out[j] = in[j] ^ mask[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