Hash.c
1.92 KB
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/*
* Hash.c --
*
* Source code for Hash, a utility procedure used by the hash
* table library.
*
* Copyright 1988 Regents of the University of California
* Permission to use, copy, modify, and distribute this
* software and its documentation for any purpose and without
* fee is hereby granted, provided that the above copyright
* notice appear in all copies. The University of California
* makes no representations about the suitability of this
* software for any purpose. It is provided "as is" without
* express or implied warranty.
*/
#ifndef lint
static char rcsid[] = "$Header: /root/leakn64/depot/rf/sw/bbplayer/simos/apps/unix/ethersim/sun/Hash.c,v 1.1.1.1 2002/05/29 01:09:09 blythe Exp $ SPRITE (Berkeley)";
#endif not lint
#include "hash.h"
#include "list.h"
/*
*---------------------------------------------------------
*
* Hash --
* This is a local procedure to compute a hash table
* bucket address based on a string value.
*
* Results:
* The return value is an integer between 0 and size - 1.
*
* Side Effects:
* None.
*
* Design:
* It is expected that most keys are decimal numbers,
* so the algorithm behaves accordingly. The randomizing
* code is stolen straight from the rand library routine.
*
*---------------------------------------------------------
*/
int
Hash(tablePtr, key)
register Hash_Table *tablePtr;
register char *key;
{
register int i = 0;
register int j;
register int *intPtr;
switch (tablePtr->keyType) {
case HASH_STRING_KEYS:
while (*key != 0) {
i = (i * 10) + (*key++ - '0');
}
break;
case HASH_ONE_WORD_KEYS:
i = (int) key;
break;
case 2:
i = ((int *) key)[0] + ((int *) key)[1];
break;
default:
j = tablePtr->keyType;
intPtr = (int *) key;
do {
i += *intPtr++;
j--;
} while (j > 0);
break;
}
return(((i*1103515245 + 12345) >> tablePtr->downShift) & tablePtr->mask);
}