archie/prospero/lib/psrv/magic.c

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2024-05-27 16:13:40 +02:00
/*
* Copyright (c) 1993 by the University of Southern California
*
* For copying and distribution information, please see the file
* <usc-license.h>.
*/
#include <usc-license.h>
#include <pfs.h> /* assert, internal_error, prototypes */
/* Generate a unique magic number (positive long). This is based upon hashing
the vlink VL's HSONAME field. */
long
generate_magic(VLINK vl)
{
long retval = 0L;
int n = p_bstlen(vl->hsoname);
int rvoffset = 0; /* offset for xoring with the return value. */
while(n--) {
rvoffset += 8;
if (rvoffset >= 8 * sizeof retval) rvoffset = 0;
retval ^= ((vl->hsoname[n]) << rvoffset);
}
if (retval < 0) return ~retval;
if (retval == 0) return 1;
return retval;
}
/* Is the magic number MAGIC anywhere in use in the list of vlinks LINKS? */
int
magic_no_in_list(long magic, VLINK links)
{
for ( ;links ; links = links->next) {
if (links->f_magic_no == magic) return TRUE;
}
return FALSE;
}