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Use XOR, not OR to combine bits.

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* gl/lib/hash-triple.c (triple_hash): Use XOR (^), not OR (|), to
combine the bits from hashing the name and those of the inode number.
Add a few comments and remove out-of-context ones.
This commit is contained in:
Jim Meyering 2007-09-25 21:27:14 +02:00
parent e2a6cbca3b
commit 0359c2e1ca
2 changed files with 10 additions and 12 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2007-09-25 Jim Meyering <jim@meyering.net>
Use XOR, not OR to combine bits.
* gl/lib/hash-triple.c (triple_hash): Use XOR (^), not OR (|), to
combine the bits from hashing the name and those of the inode number.
Add a few comments and remove out-of-context ones.
2007-09-24 Jim Meyering <jim@meyering.net>
* NEWS: The recent rm-diagnostic fix also affects cross-partition "mv".

15
gl/lib/hash-triple.c
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@ -8,27 +8,18 @@
#include "same.h"
#include "same-inode.h"
/* Hash an F_triple. */
/* Hash an F_triple, and *do* consider the file name. */
size_t
triple_hash (void const *x, size_t table_size)
{
struct F_triple const *p = x;
/* Also take the name into account, so that when moving N hard links to the
same file (all listed on the command line) all into the same directory,
we don't experience any N^2 behavior. */
/* FIXME-maybe: is it worth the overhead of doing this
just to avoid N^2 in such an unusual case? N would have
to be very large to make the N^2 factor noticable, and
one would probably encounter a limit on the length of
a command line before it became a problem. */
size_t tmp = hash_pjw (p->name, table_size);
/* Ignoring the device number here should be fine. */
return (tmp | p->st_ino) % table_size;
return (tmp ^ p->st_ino) % table_size;
}
/* Hash an F_triple. */
/* Hash an F_triple, without considering the file name. */
size_t
triple_hash_no_name (void const *x, size_t table_size)
{