Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 1 | /* Bitset primitives used by the parser generator */ |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 2 | |
Guido van Rossum | 3f5da24 | 1990-12-20 15:06:42 +0000 | [diff] [blame] | 3 | #include "pgenheaders.h" |
Guido van Rossum | 85a5fbb | 1990-10-14 12:07:46 +0000 | [diff] [blame] | 4 | #include "bitset.h" |
| 5 | |
| 6 | bitset |
| 7 | newbitset(nbits) |
| 8 | int nbits; |
| 9 | { |
| 10 | int nbytes = NBYTES(nbits); |
| 11 | bitset ss = NEW(BYTE, nbytes); |
| 12 | |
| 13 | if (ss == NULL) |
| 14 | fatal("no mem for bitset"); |
| 15 | |
| 16 | ss += nbytes; |
| 17 | while (--nbytes >= 0) |
| 18 | *--ss = 0; |
| 19 | return ss; |
| 20 | } |
| 21 | |
| 22 | void |
| 23 | delbitset(ss) |
| 24 | bitset ss; |
| 25 | { |
| 26 | DEL(ss); |
| 27 | } |
| 28 | |
| 29 | int |
| 30 | addbit(ss, ibit) |
| 31 | bitset ss; |
| 32 | int ibit; |
| 33 | { |
| 34 | int ibyte = BIT2BYTE(ibit); |
| 35 | BYTE mask = BIT2MASK(ibit); |
| 36 | |
| 37 | if (ss[ibyte] & mask) |
| 38 | return 0; /* Bit already set */ |
| 39 | ss[ibyte] |= mask; |
| 40 | return 1; |
| 41 | } |
| 42 | |
| 43 | #if 0 /* Now a macro */ |
| 44 | int |
| 45 | testbit(ss, ibit) |
| 46 | bitset ss; |
| 47 | int ibit; |
| 48 | { |
| 49 | return (ss[BIT2BYTE(ibit)] & BIT2MASK(ibit)) != 0; |
| 50 | } |
| 51 | #endif |
| 52 | |
| 53 | int |
| 54 | samebitset(ss1, ss2, nbits) |
| 55 | bitset ss1, ss2; |
| 56 | int nbits; |
| 57 | { |
| 58 | int i; |
| 59 | |
| 60 | for (i = NBYTES(nbits); --i >= 0; ) |
| 61 | if (*ss1++ != *ss2++) |
| 62 | return 0; |
| 63 | return 1; |
| 64 | } |
| 65 | |
| 66 | void |
| 67 | mergebitset(ss1, ss2, nbits) |
| 68 | bitset ss1, ss2; |
| 69 | int nbits; |
| 70 | { |
| 71 | int i; |
| 72 | |
| 73 | for (i = NBYTES(nbits); --i >= 0; ) |
| 74 | *ss1++ |= *ss2++; |
| 75 | } |