| Rev | Line | |
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| [9] | 1 | /*
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| 2 | * look.c
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| 3 | * Facility: m4 macro processor
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| 4 | * by: oz
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| 5 | */
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| 6 |
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| 7 | #include "mdef.h"
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| 8 | #include "extr.h"
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| 9 |
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| 10 | /*
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| 11 | * hash - compute hash value using the proverbial
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| 12 | * hashing function. Taken from K&R.
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| 13 | */
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| 14 | int hash (name)
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| 15 | register char *name;
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| 16 | {
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| 17 | register int h = 0;
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| 18 | while (*name)
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| 19 | h += *name++;
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| 20 | return (h % HASHSIZE);
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| 21 | }
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| 22 |
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| 23 | /*
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| 24 | * lookup - find name in the hash table
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| 25 | *
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| 26 | */
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| 27 | ndptr lookup(name)
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| 28 | char *name;
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| 29 | {
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| 30 | register ndptr p;
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| 31 |
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| 32 | for (p = hashtab[hash(name)]; p != nil; p = p->nxtptr)
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| 33 | if (strcmp(name, p->name) == 0)
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| 34 | break;
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| 35 | return (p);
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| 36 | }
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| 37 |
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| 38 | /*
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| 39 | * addent - hash and create an entry in the hash
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| 40 | * table. The new entry is added in front
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| 41 | * of a hash bucket.
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| 42 | */
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| 43 | ndptr addent(name)
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| 44 | char *name;
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| 45 | {
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| 46 | register int h;
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| 47 | ndptr p;
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| 48 |
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| 49 | h = hash(name);
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| 50 | if ((p = (ndptr) malloc(sizeof(struct ndblock))) != NULL) {
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| 51 | p->nxtptr = hashtab[h];
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| 52 | hashtab[h] = p;
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| 53 | p->name = strsave(name);
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| 54 | }
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| 55 | else
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| 56 | error("m4: no more memory.");
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| 57 | return p;
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| 58 | }
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| 59 |
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| 60 | /*
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| 61 | * remhash - remove an entry from the hashtable
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| 62 | *
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| 63 | */
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| 64 | void remhash(name, all)
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| 65 | char *name;
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| 66 | int all;
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| 67 | {
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| 68 | register int h;
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| 69 | register ndptr xp, tp, mp;
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| 70 |
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| 71 | h = hash(name);
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| 72 | mp = hashtab[h];
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| 73 | tp = nil;
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| 74 | while (mp != nil) {
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| 75 | if (strcmp(mp->name, name) == 0) {
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| 76 | mp = mp->nxtptr;
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| 77 | if (tp == nil) {
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| 78 | freent(hashtab[h]);
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| 79 | hashtab[h] = mp;
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| 80 | }
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| 81 | else {
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| 82 | xp = tp->nxtptr;
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| 83 | tp->nxtptr = mp;
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| 84 | freent(xp);
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| 85 | }
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| 86 | if (!all)
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| 87 | break;
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| 88 | }
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| 89 | else {
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| 90 | tp = mp;
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| 91 | mp = mp->nxtptr;
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| 92 | }
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| 93 | }
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| 94 | }
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| 95 |
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| 96 | /*
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| 97 | * freent - free a hashtable information block
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| 98 | *
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| 99 | */
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| 100 | void freent(p)
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| 101 | ndptr p;
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| 102 | {
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| 103 | if (!(p->type & STATIC)) {
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| 104 | free(p->name);
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| 105 | if (p->defn != null)
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| 106 | free(p->defn);
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| 107 | }
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| 108 | free(p);
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| 109 | }
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| 110 |
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