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bit_utility.h

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// portable functions for endian swap.
// in replace of ntohl()...
#include <stdint.h> // uint32_t

inline void endian_swap(unsigned short& x)
{
   x = (x >> 8) |
       (x << 8);
}

inline void endian_swap(unsigned int& x)
{
   x = (x >> 24) |
       ((x << 8) & 0x00FF0000) |
       ((x >> 8) & 0x0000FF00) |
       (x << 24);
}

/*
// __int64 for MSVC, "long long" for gcc
inline void endian_swap(unsigned __int64& x)
{
    x = (x>>56) |
        ((x<<40) & 0x00FF000000000000) |
        ((x<<24) & 0x0000FF0000000000) |
        ((x<<8)  & 0x000000FF00000000) |
        ((x>>8)  & 0x00000000FF000000) |
        ((x>>24) & 0x0000000000FF0000) |
        ((x>>40) & 0x000000000000FF00) |
        (x<<56);
}
*/

inline unsigned int get_bits(const uint32_t& word, const unsigned int& offset, const unsigned int& nbits)
{
   uint32_t mask = 0;
   for (unsigned int i = 0; i < nbits; i++)
      mask = (mask << 1) + 1;
   return (word >> offset) & mask;
}

inline bool test_bit(const uint32_t& word, const unsigned int& bit)
{
   uint32_t mask=1;
   mask = mask << bit;
   return (word & mask) == mask;
}

inline unsigned int bcd2dec(const unsigned int code) 
{
  unsigned int dec = 0;
  unsigned int bcd = code;
  int index = 1;
  while(bcd != 0) {
    dec += (bcd & 0xf) * index;
    bcd = bcd >> 4;
    index *= 10;
  }
  return dec;
}

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