Re: bz1311954 - multilib variations in LC_COLLATE files, with fixes

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Wed, Mar 20, 2019 at 9:09 PM DJ Delorie <dj@redhat.com> wrote:
>
> "Carlos O'Donell" <codonell@redhat.com> writes:
> > Very minor. Thanks, I think this means that using 50% is the simplest
> > and easiest option then. Care to post patches that use 50% with >> ?
>
> iconv, localedef: avoid floating point rounding differences
>
> Two cases of "int * 1.4" may result in imprecise results, which
> in at least one case resulted in i686 and x86-64 producing
> different locale files.  This replaced that floating point multiply
> with integer operations.  While the hash table margin is increased
> from 40% to 50%, testing shows only 2% increase in overall size
> of the locale archive.
>
> https://bugzilla.redhat.com/show_bug.cgi?id=1311954
>
> diff --git a/iconv/iconvconfig.c b/iconv/iconvconfig.c
> index 0201450742..1e6066cdf0 100644
> --- a/iconv/iconvconfig.c
> +++ b/iconv/iconvconfig.c
> @@ -1079,9 +1079,9 @@ write_output (void)
>
>    /* Create the hashing table.  We know how many strings we have.
>       Creating a perfect hash table is not reasonable here.  Therefore
> -     we use open hashing and a table size which is the next prime 40%
> +     we use open hashing and a table size which is the next prime 50%
>       larger than the number of strings.  */
> -  hash_size = next_prime (nnames * 1.4);
> +  hash_size = next_prime (nnames + nnames >> 1);
>    hash_table = (struct hash_entry *) xcalloc (hash_size,
>                                               sizeof (struct hash_entry));
>    /* Fill the hash table.  */
> diff --git a/locale/programs/ld-collate.c b/locale/programs/ld-collate.c
> index bb4e2c539d..19b23c2453 100644
> --- a/locale/programs/ld-collate.c
> +++ b/locale/programs/ld-collate.c
> @@ -2401,8 +2401,8 @@ collate_output (struct localedef_t *locale, const struct charmap_t *charmap,
>
>        runp = runp->next;
>      }
> -  /* Add 40% and find the next prime number.  */
> -  elem_size = next_prime (elem_size * 1.4);
> +  /* Add 50% and find the next prime number.  */
> +  elem_size = next_prime (elem_size + elem_size >> 1);
>
>    /* Allocate the table.  Each entry consists of two words: the hash
>       value and an index in a secondary table which provides the index

This caused:

https://sourceware.org/bugzilla/show_bug.cgi?id=24442

-- 
H.J.