1
2 /* Bitset primitives used by the parser generator */
3
4 #include "pgenheaders.h"
5 #include "bitset.h"
6
7 bitset
newbitset(int nbits)8 newbitset(int nbits)
9 {
10 int nbytes = NBYTES(nbits);
11 bitset ss = (char *)PyObject_MALLOC(sizeof(BYTE) * nbytes);
12
13 if (ss == NULL)
14 Py_FatalError("no mem for bitset");
15
16 ss += nbytes;
17 while (--nbytes >= 0)
18 *--ss = 0;
19 return ss;
20 }
21
22 void
delbitset(bitset ss)23 delbitset(bitset ss)
24 {
25 PyObject_FREE(ss);
26 }
27
28 int
addbit(bitset ss,int ibit)29 addbit(bitset ss, int ibit)
30 {
31 int ibyte = BIT2BYTE(ibit);
32 BYTE mask = BIT2MASK(ibit);
33
34 if (ss[ibyte] & mask)
35 return 0; /* Bit already set */
36 ss[ibyte] |= mask;
37 return 1;
38 }
39
40 #if 0 /* Now a macro */
41 int
42 testbit(bitset ss, int ibit)
43 {
44 return (ss[BIT2BYTE(ibit)] & BIT2MASK(ibit)) != 0;
45 }
46 #endif
47
48 int
samebitset(bitset ss1,bitset ss2,int nbits)49 samebitset(bitset ss1, bitset ss2, int nbits)
50 {
51 int i;
52
53 for (i = NBYTES(nbits); --i >= 0; )
54 if (*ss1++ != *ss2++)
55 return 0;
56 return 1;
57 }
58
59 void
mergebitset(bitset ss1,bitset ss2,int nbits)60 mergebitset(bitset ss1, bitset ss2, int nbits)
61 {
62 int i;
63
64 for (i = NBYTES(nbits); --i >= 0; )
65 *ss1++ |= *ss2++;
66 }
67