Re: [Bug-gnulib] proposed fixes for hash and hash-pjw modules

[Jim Meyering]

Paul Eggert <address@hidden> wrote:
> I found many address-calculation bugs in the hash module of gnulib.
> Much of it was due to its use of unsigned int rather than size_t, so I
> propose that we change its interfaces to use size_t rather than
> unsigned int.  There are a few more-subtle bugs (some involving
> potential rounding errors in the floating-point calculations, urk!).
>
> Here is a proposed patch.
>
> 2003-10-25  Paul Eggert  <address@hidden>
>
>       Fix several address-calculation bugs, plus some minor code cleanup.
>       While we're at it, modify hash-pjw to use the algorithm that
>       Bruno Haible recommends.
>
>       * hash.h: Include <stdbool.h>, for bool.
>       * hash.c: Don't include <stdbool.h>, since hash.h does it now.
>       * hash.h (Hash_hasher, hash_get_n_buckets, hash_get_n_buckets_used,
>       hash_get_n_entries, hash_get_max_bucket_length,
>       hash_get_entries, hash_do_for_each, hash_string, hash_initialize,
>       hash_rehash): Use size_t rather than unsigned.
>       * hash.c (struct hash_table, hash_get_n_buckets,
>       hash_get_n_buckets_used, hash_get_n_entries,
>       hash_get_max_bucket_length, hash_table_ok, hash_print_statistics,
>       hash_get_entries, hash_do_for_each, hash_string, is_prime,
>       next_prime, hash_initialize, hash_rehash, hash_delete, hash_print):
>       Likewise.
>       (SIZE_MAX): Define if not defined.
>       (hash_get_max_bucket_length, hash_table_ok, hash_lookup,
>       hash_get_first, hash_get_next, hash_get_entries, hash_do_for_each,
>       hash_print):
>       Use const * when possible.
>       (hash_string): Use (unsigned char) *P rather than *(unsigned char *) P.
>       (check_tuning): Fix bug: if tuning parameters were very close to
>       0 or 1, rounding errors could have caused subscript violations.
>       (hash_initialize, allocate_entry, hash_print): Remove unnecessary cast.
>       (hash_initialize): Add 'fail:' label
>       to free table and return NULL, and use it to simplify code.
>       Use calloc rather than clearing the storage ourself.
>       (hash_initialize, hash_rehash): Check for arithmetic overflow in
>       buffer size calculations.
>       * hash-pjw.h (hash_pjw): Use size_t, not unsigned.
>       * hash-pjw.c (hash_pjw): Likewise.
>       Switch to method described by Bruno Haible.
>       Include <limits.h>, for CHAR_BIT.
>       (SIZE_BITS): New macro.

Thanks!
I've applied all of that and have made the corresponding
adjustments in coreutils.