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C++ write bit by bit

Stormy Stag answered on December 17, 2023 Popularity 3/10 Helpfulness 1/10

answer C++ write bit by bit

C++ write bit by bit

Comment

unsigned buf = 0, bits = 0;

...

// some loop
{
   ...

   // write one bit (don't need the & if you know x is 0 or 1)
   buf = (buf << 1) | (x & 1);
   bits++;

   ...

   // write three bits
   buf = (buf << 3) | (y & 7);
   bits += 3;

   ...

   // write bytes from the buffer before it fills the integer length
   if (bits >= 8) {     // the if could be a while if expect 16 or more
       // out is an ostream -- must be in binary mode if on Windows
       bits -= 8;
       out.put(buf >> bits);
   }

   ...

}

...

// write any leftover bits (it is assumed here that bits is in 0..7 --
// if not, first repeat if or while from above to clear out bytes)
if (bits) {
    out.put(buf << (8 - bits));
    bits = 0;
}

...

Popularity 3/10 Helpfulness 1/10 Language cpp

Source: stackoverflow.com

Tags: bit c++

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