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/*
* intern.c logo data interning module dvb
*
* Copyright (C) 1993 by the Regents of the University of California
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
*/
#include "logo.h"
#include "globals.h"
NODE *hash_table[HASH_LEN] = {NIL};
void map_oblist(void (*fcn)()) {
int i;
NODE *nd;
for (i = 0; i < HASH_LEN; i++)
for (nd = hash_table[i]; nd != NIL; nd = cdr(nd))
(*fcn) (car(nd));
}
FIXNUM hash(char *s, int len) {
/* Map S to an integer in the range 0 .. HASH_LEN-1. */
/* Method attributed to Peter Weinberger, adapted from Aho, Sethi, */
/* and Ullman's book, Compilers: Principles, Techniques, and */
/* Tools; figure 7.35. */
unsigned FIXNUM h = 0, g;
while (--len >= 0) {
h = (h << 4) + (FIXNUM)(*s++);
g = h & (0xf << (WORDSIZE-4));
if (g != 0) {
h ^= g ^ (g >> (WORDSIZE-8));
}
}
return h % HASH_LEN;
}
NODE *make_case(NODE *casestrnd, NODE *obj) {
NODE *new_caseobj, *clistptr;
clistptr = caselistptr__object(obj);
new_caseobj = make_caseobj(casestrnd, obj);
setcdr(clistptr, cons(new_caseobj, cdr(clistptr)));
return(new_caseobj);
}
NODE *make_object(NODE *canonical, NODE *oproc, NODE *val,
NODE *plist, NODE *casestrnd) {
NODE *temp;
temp = cons_list(0, canonical, oproc, val, plist,
make_intnode((FIXNUM)0), END_OF_LIST);
make_case(casestrnd, temp);
return(temp);
}
NODE *make_instance(NODE *casend, NODE *lownd) {
NODE *obj;
FIXNUM hashind;
/* Called only if arg isn't already in hash table */
obj = make_object(lownd, UNDEFINED, UNBOUND, NIL, casend);
hashind = hash(getstrptr(lownd), getstrlen(lownd));
push(obj,(hash_table[hashind]));
return car(caselist__object(obj));
}
NODE *find_instance(NODE *lownd) {
NODE *hash_entry, *thisobj = NIL;
int cmpresult;
hash_entry = hash_table[hash(getstrptr(lownd), getstrlen(lownd))];
while (hash_entry != NIL) {
thisobj = car(hash_entry);
cmpresult = compare_node(lownd, canonical__object(thisobj), FALSE);
if (cmpresult == 0)
break;
else
hash_entry = cdr(hash_entry);
}
if (hash_entry == NIL) return(NIL);
else return(thisobj);
}
int case_compare(NODE *nd1, NODE *nd2) {
if (backslashed(nd1) && backslashed(nd2)) {
if (getstrlen(nd1) != getstrlen(nd2)) return(1);
return(strncmp(getstrptr(nd1), getstrptr(nd2),
getstrlen(nd1)));
}
if (backslashed(nd1) || backslashed(nd2))
return(1);
return(compare_node(nd1, nd2, FALSE));
}
NODE *find_case(NODE *strnd, NODE *obj) {
NODE *clist;
clist = caselist__object(obj);
while (clist != NIL &&
case_compare(strnd, strnode__caseobj(car(clist))))
clist = cdr(clist);
if (clist == NIL) return(NIL);
else return(car(clist));
}
NODE *intern(NODE *nd) {
NODE *obj, *casedes, *lownd;
if (nodetype(nd) == CASEOBJ) return(nd);
nd = cnv_node_to_strnode(nd);
lownd = make_strnode(getstrptr(nd), (struct string_block *)NULL,
getstrlen(nd), STRING, noparitylow_strnzcpy);
if ((obj = find_instance(lownd)) != NIL) {
if ((casedes = find_case(nd, obj)) == NIL)
casedes = make_case(nd, obj);
} else
casedes = make_instance(nd, lownd);
return(casedes);
}
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