127 lines
2.7 KiB
C
Executable File
127 lines
2.7 KiB
C
Executable File
/* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
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/* All Rights Reserved */
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/* THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE OF AT&T */
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/* The copyright notice above does not evidence any */
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/* actual or intended publication of such source code. */
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#ident "@(#)hashlook.c 1.10 95/03/16 SMI" /* SVr4.0 1.8 */
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#include <stdlib.h>
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#include <stdio.h>
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#include "hash.h"
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#include "huff.h"
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unsigned *table;
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int index[NI];
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#define B (BYTE * sizeof (unsigned))
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#define L (BYTE * sizeof (long)-1)
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#define MASK (~((unsigned long)1L<<L))
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#ifdef pdp11 /* sizeof (unsigned)==sizeof(long)/2 */
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#define fetch(wp, bp)\
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(((((long)wp[0]<<B)|wp[1])<<(B-bp))|(wp[2]>>bp))
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#else /* sizeof (unsigned)==sizeof(long) */
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#define fetch(wp, bp) ((wp[0] << (B - bp)) | (wp[1] >> bp))
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#endif
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int
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hashlook(char *s)
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{
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unsigned long h;
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unsigned long t;
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register bp;
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register unsigned *wp;
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long sum;
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unsigned *tp;
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h = hash(s);
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t = h>>(HASHWIDTH-INDEXWIDTH);
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wp = &table[index[t]];
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tp = &table[index[t+1]];
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bp = B;
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sum = (long)t<<(HASHWIDTH-INDEXWIDTH);
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for (;;) {
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{
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/*
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* this block is equivalent to:
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* bp -= decode((fetch(wp, bp) >> 1) & MASK, &t);
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*/
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long y;
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long v;
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#if u3b || u3b5 || u3b2 || sparc || i386
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/*
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* shift 32 on those machines leaves destination
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* unchanged
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*/
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if (bp == 0)
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y = 0;
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else
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y = wp[0] << (B - bp);
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if (bp < 32)
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y |= (wp[1] >> bp);
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y = (y >> 1) & MASK;
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#else
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y = (fetch(wp, bp) >> 1) & MASK;
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#endif
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if (y < cs) {
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t = y >> (long) (L+1-w);
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bp -= w-1;
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} else {
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for (bp -= w, v = v0; y >= qcs;
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y = (y << 1) & MASK, v += n)
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bp -= 1;
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t = v + (y>> (long)(L-w));
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}
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}
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while (bp <= 0) {
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bp += B;
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wp++;
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}
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if (wp >= tp && (wp > tp||bp < B))
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return (0);
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sum += t;
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if (sum < h)
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continue;
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return (sum == h);
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}
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}
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int
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prime(char *file)
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{
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register FILE *f;
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#ifdef pdp11 /* because of insufficient address space for buffers */
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fd = dup(0);
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close(0);
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if (open(file, 0) != 0)
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return (0);
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f = stdin;
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if (rhuff(f) == 0 || read(fileno(f), (char *)index,
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NI * sizeof (*index)) != NI * sizeof (*index) ||
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(table = (unsigned *)malloc(index[NI-1] * sizeof (*table))) == 0 ||
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read(fileno(f), (char *)table, sizeof (*table) * index[NI-1]) !=
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index[NI-1] * sizeof (*table))
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return (0);
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close(0);
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if (dup(fd) != 0)
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return (0);
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close(fd);
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#else
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if ((f = fopen(file, "r")) == NULL)
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return (0);
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if (rhuff(f) == 0 ||
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fread((char *)index, sizeof (*index), NI, f) != NI ||
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(table = (unsigned *)malloc(index[NI-1] * sizeof (*table))) == 0 ||
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fread((char *)table, sizeof (*table), index[NI-1], f) !=
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index[NI-1])
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return (0);
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(void) fclose(f);
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#endif
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hashinit();
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return (1);
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}
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