cpython/Parser/bitset.c

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/* Bitset primitives used by the parser generator */
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#include "pgenheaders.h"
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#include "bitset.h"
bitset
newbitset(int nbits)
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{
int nbytes = NBYTES(nbits);
bitset ss = (char *)PyObject_MALLOC(sizeof(BYTE) * nbytes);
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if (ss == NULL)
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Py_FatalError("no mem for bitset");
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ss += nbytes;
while (--nbytes >= 0)
*--ss = 0;
return ss;
}
void
delbitset(bitset ss)
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{
PyObject_FREE(ss);
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}
int
addbit(bitset ss, int ibit)
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{
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)
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{
return (ss[BIT2BYTE(ibit)] & BIT2MASK(ibit)) != 0;
}
#endif
int
samebitset(bitset ss1, bitset ss2, int nbits)
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{
int i;
for (i = NBYTES(nbits); --i >= 0; )
if (*ss1++ != *ss2++)
return 0;
return 1;
}
void
mergebitset(bitset ss1, bitset ss2, int nbits)
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{
int i;
for (i = NBYTES(nbits); --i >= 0; )
*ss1++ |= *ss2++;
}