111 lines
1.6 KiB
C
111 lines
1.6 KiB
C
/*
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* look.c
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* Facility: m4 macro processor
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* by: oz
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*/
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#include "mdef.h"
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#include "extr.h"
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/*
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* hash - compute hash value using the proverbial
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* hashing function. Taken from K&R.
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*/
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int hash (name)
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register char *name;
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{
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register int h = 0;
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while (*name)
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h += *name++;
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return (h % HASHSIZE);
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}
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/*
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* lookup - find name in the hash table
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*
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*/
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ndptr lookup(name)
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char *name;
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{
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register ndptr p;
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for (p = hashtab[hash(name)]; p != nil; p = p->nxtptr)
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if (strcmp(name, p->name) == 0)
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break;
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return (p);
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}
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/*
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* addent - hash and create an entry in the hash
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* table. The new entry is added in front
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* of a hash bucket.
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*/
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ndptr addent(name)
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char *name;
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{
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register int h;
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ndptr p;
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h = hash(name);
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if ((p = (ndptr) malloc(sizeof(struct ndblock))) != NULL) {
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p->nxtptr = hashtab[h];
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hashtab[h] = p;
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p->name = strsave(name);
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}
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else
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error("m4: no more memory.");
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return p;
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}
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/*
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* remhash - remove an entry from the hashtable
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*
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*/
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void remhash(name, all)
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char *name;
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int all;
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{
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register int h;
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register ndptr xp, tp, mp;
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h = hash(name);
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mp = hashtab[h];
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tp = nil;
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while (mp != nil) {
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if (strcmp(mp->name, name) == 0) {
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mp = mp->nxtptr;
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if (tp == nil) {
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freent(hashtab[h]);
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hashtab[h] = mp;
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}
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else {
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xp = tp->nxtptr;
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tp->nxtptr = mp;
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freent(xp);
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}
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if (!all)
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break;
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}
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else {
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tp = mp;
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mp = mp->nxtptr;
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}
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}
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}
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/*
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* freent - free a hashtable information block
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*
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*/
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void freent(p)
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ndptr p;
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{
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if (!(p->type & STATIC)) {
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free(p->name);
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if (p->defn != null)
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free(p->defn);
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}
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free(p);
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}
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