/* Bitset primitives used by the parser generator */

#include "pgenheaders.h"
#include "bitset.h"

bitset
newbitset(int nbits)
{
 int nbytes = NBYTES(nbits);
 bitset ss = (char *)PyObject_MALLOC(sizeof(BYTE) * nbytes);

 if (ss == NULL)
 Py_FatalError("no mem for bitset");

 ss += nbytes;
 while (--nbytes >= 0)
 *--ss = 0;
 return ss;
}

void
delbitset(bitset ss)
{
 PyObject_FREE(ss);
}

int
addbit(bitset ss, int ibit)
{
 int ibyte = BIT2BYTE(ibit);
 BYTE mask = BIT2MASK(ibit);

 if (ss[ibyte] & mask)
 return 0; /* Bit already set */
 ss[ibyte] |= mask;
 return 1;
}

#if 0 /* Now a macro */
int
testbit(bitset ss, int ibit)
{
 return (ss[BIT2BYTE(ibit)] & BIT2MASK(ibit)) != 0;
}
#endif

int
samebitset(bitset ss1, bitset ss2, int nbits)
{
 int i;

 for (i = NBYTES(nbits); --i >= 0; )
 if (*ss1++ != *ss2++)
 return 0;
 return 1;
}

void
mergebitset(bitset ss1, bitset ss2, int nbits)
{
 int i;

 for (i = NBYTES(nbits); --i >= 0; )
 *ss1++ |= *ss2++;
}