diff options
Diffstat (limited to 'libiberty/hashtab.c')
| -rw-r--r-- | libiberty/hashtab.c | 66 |
1 files changed, 58 insertions, 8 deletions
diff --git a/libiberty/hashtab.c b/libiberty/hashtab.c index 4bcccee..9778998 100644 --- a/libiberty/hashtab.c +++ b/libiberty/hashtab.c @@ -62,7 +62,7 @@ Boston, MA 02111-1307, USA. */ static unsigned long higher_prime_number PARAMS ((unsigned long)); static hashval_t hash_pointer PARAMS ((const void *)); static int eq_pointer PARAMS ((const void *, const void *)); -static void htab_expand PARAMS ((htab_t)); +static int htab_expand PARAMS ((htab_t)); static PTR *find_empty_slot_for_expand PARAMS ((htab_t, hashval_t)); /* At some point, we could make these be NULL, and modify the @@ -124,7 +124,7 @@ eq_pointer (p1, p2) /* This function creates table with length slightly longer than given source length. Created hash table is initiated as empty (all the hash table entries are EMPTY_ENTRY). The function returns the - created hash table. */ + created hash table. Memory allocation must not fail. */ htab_t htab_create (size, hash_f, eq_f, del_f) @@ -142,6 +142,41 @@ htab_create (size, hash_f, eq_f, del_f) result->hash_f = hash_f; result->eq_f = eq_f; result->del_f = del_f; + result->return_allocation_failure = 0; + return result; +} + +/* This function creates table with length slightly longer than given + source length. The created hash table is initiated as empty (all the + hash table entries are EMPTY_ENTRY). The function returns the created + hash table. Memory allocation may fail; it may return NULL. */ + +htab_t +htab_try_create (size, hash_f, eq_f, del_f) + size_t size; + htab_hash hash_f; + htab_eq eq_f; + htab_del del_f; +{ + htab_t result; + + size = higher_prime_number (size); + result = (htab_t) calloc (1, sizeof (struct htab)); + if (result == NULL) + return NULL; + + result->entries = (PTR *) calloc (size, sizeof (PTR)); + if (result->entries == NULL) + { + free (result); + return NULL; + } + + result->size = size; + result->hash_f = hash_f; + result->eq_f = eq_f; + result->del_f = del_f; + result->return_allocation_failure = 1; return result; } @@ -216,9 +251,11 @@ find_empty_slot_for_expand (htab, hash) entries and repeatedly inserts the table elements. The occupancy of the table after the call will be about 50%. Naturally the hash table must already exist. Remember also that the place of the - table entries is changed. */ + table entries is changed. If memory allocation failures are allowed, + this function will return zero, indicating that the table could not be + expanded. If all goes well, it will return a non-zero value. */ -static void +static int htab_expand (htab) htab_t htab; { @@ -230,7 +267,16 @@ htab_expand (htab) olimit = oentries + htab->size; htab->size = higher_prime_number (htab->size * 2); - htab->entries = (PTR *) xcalloc (htab->size, sizeof (PTR *)); + + if (htab->return_allocation_failure) + { + PTR *nentries = (PTR *) calloc (htab->size, sizeof (PTR *)); + if (nentries == NULL) + return 0; + htab->entries = nentries; + } + else + htab->entries = (PTR *) xcalloc (htab->size, sizeof (PTR *)); htab->n_elements -= htab->n_deleted; htab->n_deleted = 0; @@ -252,6 +298,7 @@ htab_expand (htab) while (p < olimit); free (oentries); + return 1; } /* This function searches for a hash table entry equal to the given @@ -308,7 +355,9 @@ htab_find (htab, element) equal to the given element. To delete an entry, call this with INSERT = 0, then call htab_clear_slot on the slot returned (possibly after doing some checks). To insert an entry, call this with - INSERT = 1, then write the value you want into the returned slot. */ + INSERT = 1, then write the value you want into the returned slot. + When inserting an entry, NULL may be returned if memory allocation + fails. */ PTR * htab_find_slot_with_hash (htab, element, hash, insert) @@ -322,8 +371,9 @@ htab_find_slot_with_hash (htab, element, hash, insert) hashval_t hash2; size_t size; - if (insert == INSERT && htab->size * 3 <= htab->n_elements * 4) - htab_expand (htab); + if (insert == INSERT && htab->size * 3 <= htab->n_elements * 4 + && htab_expand (htab) == 0) + return NULL; size = htab->size; hash2 = 1 + hash % (size - 2); |