84 lines
1.8 KiB
C
84 lines
1.8 KiB
C
/* h a s h . c
|
|
*
|
|
* maintains the the lists of hashed patterns
|
|
* Functions : addtohashtable() and printhashtable()
|
|
*/
|
|
# include <stdio.h>
|
|
# include "misc.h"
|
|
|
|
struct hlist { /* linear list of pattern numbers */
|
|
int h_patno;
|
|
struct hlist *h_next;
|
|
};
|
|
|
|
static struct hlist *hashtable[129]; /* an array of ptr's to these lists,
|
|
* the index in the array is the
|
|
* result of hashing
|
|
*/
|
|
|
|
static unsigned
|
|
hash(string) char *string; {
|
|
register char *p;
|
|
register unsigned i,sum;
|
|
|
|
if (strcmp(string,"ANY") == 0) return 128;
|
|
for (sum=i=0,p=string;*p;i += 3)
|
|
sum += (*p++)<<(i&03);
|
|
return sum % 128;
|
|
}
|
|
|
|
|
|
addtohashtable(s,n) char *s; {
|
|
/*
|
|
* Add a new pattern number to the hashtable.
|
|
* s is the key, n the pattern number
|
|
*/
|
|
unsigned hval;
|
|
register struct hlist *p;
|
|
char *malloc();
|
|
|
|
hval = hash(s);
|
|
p = (struct hlist *) malloc(sizeof *p);
|
|
p->h_patno = n;
|
|
/*
|
|
* Now insert in front of the list
|
|
* This way, the list will be sorted from high to low, which is the
|
|
* wrong way around, but easy
|
|
*/
|
|
p->h_next = hashtable[hval];
|
|
hashtable[hval] = p;
|
|
}
|
|
|
|
static
|
|
prhlist(p) struct hlist *p; {
|
|
/*
|
|
* Print a list in reversed order (see comment above)
|
|
*/
|
|
|
|
if (p) {
|
|
prhlist(p->h_next);
|
|
fprintf(genc,"%d, ",p->h_patno - 1);
|
|
}
|
|
}
|
|
|
|
printhashtable() {
|
|
/*
|
|
* Print the linear lists, and also output an array of
|
|
* pointers to them
|
|
*/
|
|
register i;
|
|
register struct hlist *p;
|
|
|
|
for (i = 1; i <= 128; i++) {
|
|
fprintf(genc,"int hash%d[] = { ",i);
|
|
prhlist(hashtable[i-1]);
|
|
fputs("-1};\n",genc);
|
|
}
|
|
fputs("int hashany[] = { ", genc);
|
|
prhlist(hashtable[128]);
|
|
fputs("-1 };\n",genc);
|
|
fputs("int *hashtab[] = {",genc);
|
|
for (i = 1; i <= 128; i++) fprintf(genc,"hash%d,",i);
|
|
fputs("hashany};\n",genc);
|
|
}
|