skalibs

Mirror/fork of https://skarnet.org/software/skalibs/
git clone https://ccx.te2000.cz/git/skalibs
Log | Files | Refs | README | LICENSE

bitarray_not.c (405B)

      1 /* ISC license. */
      2 
      3 #include <skalibs/bitarray.h>
      4 
      5 void bitarray_not (unsigned char *s, size_t a, size_t b)
      6 {
      7   if (!b) return ;
      8   b += a ;
      9   if ((a >> 3) == ((b-1) >> 3))
     10     s[a>>3] ^= ((1 << (a & 7)) - 1) ^ ((1 << (1 + (b-1 & 7))) - 1) ;
     11   else
     12   {
     13     size_t i = (a>>3) + 1 ;
     14     s[a>>3] ^= ~((1 << (a & 7)) - 1) ;
     15     for (; i < (b>>3) ; i++) s[i] = ~s[i] ;
     16     s[b>>3] ^= (1 << (b & 7)) - 1 ;
     17   }
     18 }