84 lines
1.8 KiB
C
84 lines
1.8 KiB
C
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/* h a s h . c
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*
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* maintains the the lists of hashed patterns
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* Functions : addtohashtable() and printhashtable()
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*/
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# include <stdio.h>
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# include "misc.h"
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struct hlist { /* linear list of pattern numbers */
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int h_patno;
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struct hlist *h_next;
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};
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static struct hlist *hashtable[129]; /* an array of ptr's to these lists,
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* the index in the array is the
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* result of hashing
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*/
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static unsigned
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hash(string) char *string; {
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register char *p;
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register unsigned i,sum;
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if (strcmp(string,"ANY") == 0) return 128;
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for (sum=i=0,p=string;*p;i += 3)
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sum += (*p++)<<(i&07);
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return sum % 127;
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}
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addtohashtable(s,n) char *s; {
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/*
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* Add a new pattern number to the hashtable.
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* s is the key, n the pattern number
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*/
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unsigned hval;
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register struct hlist *p;
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char *malloc();
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hval = hash(s);
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p = (struct hlist *) malloc(sizeof *p);
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p->h_patno = n;
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/*
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* Now insert in front of the list
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* This way, the list will be sorted from high to low, which is the
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* wrong way around, but easy
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*/
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p->h_next = hashtable[hval];
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hashtable[hval] = p;
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}
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static
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prhlist(p) struct hlist *p; {
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/*
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* Print a list in reversed order (see comment above)
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*/
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if (p) {
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prhlist(p->h_next);
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fprintf(genc,"%d, ",p->h_patno - 1);
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}
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}
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printhashtable() {
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/*
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* Print the linear lists, and also output an array of
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* pointers to them
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*/
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register i;
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register struct hlist *p;
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for (i = 1; i <= 128; i++) {
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fprintf(genc,"int hash%d[] = { ",i);
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prhlist(hashtable[i-1]);
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fputs("-1};\n",genc);
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}
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fputs("int hashany[] = { ", genc);
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prhlist(hashtable[128]);
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fputs("-1 };\n",genc);
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fputs("int *hashtab[] = {",genc);
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for (i = 1; i <= 128; i++) fprintf(genc,"hash%d,",i);
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fputs("hashany};\n",genc);
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}
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