Dogcows Code - chaz/yoink/blob - src/stlplus/persistence/persistent_bitset.tpp

   1 ////////////////////////////////////////////////////////////////////////////////
   2
   3 //   Author:    Andy Rushton
   4 //   Copyright: (c) Southampton University 1999-2004
   5 //              (c) Andy Rushton           2004-2009
   6 //   License:   BSD License, see ../docs/license.html
   7
   8 ////////////////////////////////////////////////////////////////////////////////
   9 #include "persistent_int.hpp"
  10
  11 namespace stlplus
  12 {
  13
  14   ////////////////////////////////////////////////////////////////////////////////
  15   // format: data msB first, packed into bytes with lowest index at the byte's lsb
  16
  17   // Note: the interface does not provide access to the internal storage and yet
  18   // to be efficient the std::bitset must be packed as bytes. Thus I have to do it the
  19   // hard way.
  20
  21   template<size_t N>
  22   void dump_bitset(dump_context& context, const std::bitset<N>& data)
  23     throw(persistent_dump_failed)
  24   {
  25     size_t bits = data.size();
  26     size_t bytes = (bits+7)/8;
  27     for (size_t B = bytes; B--; )
  28     {
  29       unsigned char ch = 0;
  30       for (size_t b = 0; b < 8; b++)
  31       {
  32         size_t bit = B*8+b;
  33         if (bit < bits && data.test(bit))
  34           ch |= (0x01 << b);
  35       }
  36       dump_unsigned_char(context,ch);
  37     }
  38   }
  39
  40   template<size_t N>
  41   void restore_bitset(restore_context& context, std::bitset<N>& data)
  42     throw(persistent_restore_failed)
  43   {
  44     size_t bits = data.size();
  45     size_t bytes = (bits+7)/8;
  46     for (size_t B = bytes; B--; )
  47     {
  48       unsigned char ch = 0;
  49       restore_unsigned_char(context,ch);
  50       for (size_t b = 0; b < 8; b++)
  51       {
  52         size_t bit = B*8+b;
  53         if (bit >= bits) break;
  54         data.set(bit, ch & (0x01 << b) ? true : false);
  55       }
  56     }
  57   }
  58
  59   ////////////////////////////////////////////////////////////////////////////////
  60
  61 } // end namespace stlplus