/*

* look.c

* Facility: m4 macro processor

* by: oz

*/

#include "mdef.h"

#include "extr.h"

/*

* hash - compute hash value using the proverbial

* hashing function. Taken from K&R.

*/

int hash (name)

register char *name;

{

register int h = 0;

while (*name)

h += *name++;

return (h % HASHSIZE);

}

/*

* lookup - find name in the hash table

*

*/

ndptr lookup(name)

char *name;

{

register ndptr p;

for (p = hashtab[hash(name)]; p != nil; p = p->nxtptr)

if (strcmp(name, p->name) == 0)

break;

return (p);

}

/*

* addent - hash and create an entry in the hash

* table. The new entry is added in front

* of a hash bucket.

*/

ndptr addent(name)

char *name;

{

register int h;

ndptr p;

h = hash(name);

if ((p = (ndptr) malloc(sizeof(struct ndblock))) != NULL) {

p->nxtptr = hashtab[h];

hashtab[h] = p;

p->name = strsave(name);

}

else

error("m4: no more memory.");

return p;

}

/*

* remhash - remove an entry from the hashtable

*

*/

void remhash(name, all)

char *name;

int all;

{

register int h;

register ndptr xp, tp, mp;

h = hash(name);

mp = hashtab[h];

tp = nil;

while (mp != nil) {

if (strcmp(mp->name, name) == 0) {

mp = mp->nxtptr;

if (tp == nil) {

freent(hashtab[h]);

hashtab[h] = mp;

}

else {

xp = tp->nxtptr;

tp->nxtptr = mp;

freent(xp);

}

if (!all)

break;

}

else {

tp = mp;

mp = mp->nxtptr;

}

}

}

/*

* freent - free a hashtable information block

*

*/

void freent(p)

ndptr p;

{

if (!(p->type & STATIC)) {

free(p->name);

if (p->defn != null)

free(p->defn);

}

free(p);

}