#include "libiberty.h"
#include "hashtab.h"
-/* The following variable is used for debugging. Its value is number
- of all calls of `find_hash_table_entry' for all hash tables. */
-
-static int all_searches = 0;
-
-/* The following variable is used for debugging. Its value is number
- of collisions fixed for time of work with all hash tables. */
-
-static int all_collisions = 0;
-
-/* The following variable is used for debugging. Its value is number
- of all table expansions fixed for time of work with all hash
- tables. */
-
-static int all_expansions = 0;
-
/* This macro defines reserved value for empty table entry. */
-#define EMPTY_ENTRY NULL
+#define EMPTY_ENTRY ((void *) 0)
/* This macro defines reserved value for table entry which contained
a deleted element. */
greater than given source number. */
static unsigned long
-higher_prime_number (number)
- unsigned long number;
+higher_prime_number (n)
+ unsigned long n;
{
unsigned long i;
- for (number = (number / 2) * 2 + 3;; number += 2)
+ n |= 0x01; /* Force N to be odd. */
+ if (n < 9)
+ return n; /* All odd numbers < 9 are prime. */
+
+ next:
+ n += 2;
+ i = 3;
+ do
{
- for (i = 3; i * i <= number; i += 2)
- if (number % i == 0)
- break;
- if (i * i > number)
- return number;
+ if (n % i == 0)
+ goto next;
+ i += 2;
}
+ while ((i * i) <= n);
+
+ return n;
}
/* This function creates table with length slightly longer than given
hash table entries are EMPTY_ENTRY). The function returns the
created hash table. */
-hash_table_t
-create_hash_table (size, hash_function, eq_function)
+htab_t
+htab_create (size, hash_f, eq_f)
size_t size;
- unsigned (*hash_function) PARAMS ((hash_table_entry_t));
- int (*eq_function) PARAMS ((hash_table_entry_t, hash_table_entry_t));
+ htab_hash hash_f;
+ htab_eq eq_f;
{
- hash_table_t result;
+ htab_t result;
size = higher_prime_number (size);
- result = (hash_table_t) xmalloc (sizeof (*result));
- result->entries
- = (hash_table_entry_t *) xmalloc (size * sizeof (hash_table_entry_t));
+ result = (htab_t) xcalloc (1, sizeof (struct htab));
+ result->entries = (void **) xcalloc (size, sizeof (void *));
result->size = size;
- result->hash_function = hash_function;
- result->eq_function = eq_function;
- result->number_of_elements = 0;
- result->number_of_deleted_elements = 0;
- result->searches = 0;
- result->collisions = 0;
- memset (result->entries, 0, size * sizeof (hash_table_entry_t));
+ result->hash_f = hash_f;
+ result->eq_f = eq_f;
return result;
}
Naturally the hash table must already exist. */
void
-delete_hash_table (htab)
- hash_table_t htab;
+htab_delete (htab)
+ htab_t htab;
{
free (htab->entries);
free (htab);
/* This function clears all entries in the given hash table. */
void
-empty_hash_table (htab)
- hash_table_t htab;
+htab_empty (htab)
+ htab_t htab;
{
- memset (htab->entries, 0, htab->size * sizeof (hash_table_entry_t));
+ memset (htab->entries, 0, htab->size * sizeof (void *));
}
/* The following function changes size of memory allocated for the
table entries is changed. */
static void
-expand_hash_table (htab)
- hash_table_t htab;
+htab_expand (htab)
+ htab_t htab;
{
- hash_table_t new_htab;
- hash_table_entry_t *entry_ptr;
- hash_table_entry_t *new_entry_ptr;
-
- new_htab = create_hash_table (htab->number_of_elements * 2,
- htab->hash_function, htab->eq_function);
- for (entry_ptr = htab->entries; entry_ptr < htab->entries + htab->size;
- entry_ptr++)
- if (*entry_ptr != EMPTY_ENTRY && *entry_ptr != DELETED_ENTRY)
- {
- new_entry_ptr = find_hash_table_entry (new_htab, *entry_ptr, 1);
- *new_entry_ptr = (*entry_ptr);
- }
- free (htab->entries);
- *htab = (*new_htab);
- free (new_htab);
+ void **oentries;
+ void **olimit;
+ void **p;
+
+ oentries = htab->entries;
+ olimit = oentries + htab->size;
+
+ htab->size = higher_prime_number (htab->size * 2);
+ htab->entries = xcalloc (htab->size, sizeof (void **));
+
+ htab->n_elements -= htab->n_deleted;
+ htab->n_deleted = 0;
+
+ p = oentries;
+ do
+ {
+ void *x = *p;
+ if (x != EMPTY_ENTRY && x != DELETED_ENTRY)
+ {
+ void **q = htab_find_slot (htab, x, 1);
+ *q = x;
+ }
+ p++;
+ }
+ while (p < olimit);
+ free (oentries);
}
-/* This function searches for hash table entry which contains element
- equal to given value or empty entry in which given value can be
- placed (if the element with given value does not exist in the
- table). The function works in two regimes. The first regime is
- used only for search. The second is used for search and
- reservation empty entry for given value. The table is expanded if
- occupancy (taking into accout also deleted elements) is more than
- 75%. Naturally the hash table must already exist. If reservation
- flag is TRUE then the element with given value should be inserted
- into the table entry before another call of
- `find_hash_table_entry'. */
-
-hash_table_entry_t *
-find_hash_table_entry (htab, element, reserve)
- hash_table_t htab;
- hash_table_entry_t element;
- int reserve;
+/* This function searches for a hash table entry equal to the given
+ element. It cannot be used to insert or delete an element. */
+
+void *
+htab_find (htab, element)
+ htab_t htab;
+ const void *element;
{
- hash_table_entry_t *entry_ptr;
- hash_table_entry_t *first_deleted_entry_ptr;
- unsigned index, hash_value, secondary_hash_value;
+ unsigned int index, hash, hash2;
+ size_t size;
+
+ htab->searches++;
+ size = htab->size;
+ hash = (*htab->hash_f) (element);
+ hash2 = 1 + hash % (size - 2);
+ index = hash % size;
- if (htab->size * 3 <= htab->number_of_elements * 4)
+ for (;;)
{
- all_expansions++;
- expand_hash_table (htab);
+ void *entry = htab->entries[index];
+ if (entry == EMPTY_ENTRY)
+ return NULL;
+ else if (entry != DELETED_ENTRY && (*htab->eq_f) (entry, element))
+ return entry;
+
+ htab->collisions++;
+ index += hash2;
+ if (index >= size)
+ index -= size;
}
- hash_value = (*htab->hash_function) (element);
- secondary_hash_value = 1 + hash_value % (htab->size - 2);
- index = hash_value % htab->size;
+}
+
+/* This function searches for a hash table slot containing an entry
+ 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. */
+
+void **
+htab_find_slot (htab, element, insert)
+ htab_t htab;
+ const void *element;
+ int insert;
+{
+ void **first_deleted_slot;
+ unsigned int index, hash, hash2;
+ size_t size;
+
+ if (insert && htab->size * 3 <= htab->n_elements * 4)
+ htab_expand (htab);
+
+ size = htab->size;
+ hash = (*htab->hash_f) (element);
+ hash2 = 1 + hash % (size - 2);
+ index = hash % size;
+
htab->searches++;
- all_searches++;
- first_deleted_entry_ptr = NULL;
- for (;;htab->collisions++, all_collisions++)
+ first_deleted_slot = NULL;
+
+ for (;;)
{
- entry_ptr = htab->entries + index;
- if (*entry_ptr == EMPTY_ENTRY)
- {
- if (reserve)
+ void *entry = htab->entries[index];
+ if (entry == EMPTY_ENTRY)
+ {
+ if (!insert)
+ return NULL;
+
+ htab->n_elements++;
+
+ if (first_deleted_slot)
{
- htab->number_of_elements++;
- if (first_deleted_entry_ptr != NULL)
- {
- entry_ptr = first_deleted_entry_ptr;
- *entry_ptr = EMPTY_ENTRY;
- }
+ *first_deleted_slot = EMPTY_ENTRY;
+ return first_deleted_slot;
}
- break;
- }
- else if (*entry_ptr != DELETED_ENTRY)
- {
- if ((*htab->eq_function) (*entry_ptr, element))
- break;
- }
- else if (first_deleted_entry_ptr == NULL)
- first_deleted_entry_ptr = entry_ptr;
- index += secondary_hash_value;
- if (index >= htab->size)
- index -= htab->size;
+
+ return &htab->entries[index];
+ }
+
+ if (entry == DELETED_ENTRY)
+ {
+ if (!first_deleted_slot)
+ first_deleted_slot = &htab->entries[index];
+ }
+ else
+ {
+ if ((*htab->eq_f) (entry, element))
+ return &htab->entries[index];
+ }
+
+ htab->collisions++;
+ index += hash2;
+ if (index >= size)
+ index -= size;
}
- return entry_ptr;
}
-/* This function deletes element with given value from hash table.
- The hash table entry value will be `DELETED_ENTRY' after the
- function call. Naturally the hash table must already exist. Hash
- table entry for given value should be not empty (or deleted). */
+/* This function deletes an element with the given value from hash
+ table. If there is no matching element in the hash table, this
+ function does nothing. */
void
-remove_element_from_hash_table_entry (htab, element)
- hash_table_t htab;
- hash_table_entry_t element;
+htab_remove_elt (htab, element)
+ htab_t htab;
+ void *element;
{
- hash_table_entry_t *entry_ptr;
+ void **slot;
- entry_ptr = find_hash_table_entry (htab, element, 0);
- *entry_ptr = DELETED_ENTRY;
- htab->number_of_deleted_elements++;
+ slot = htab_find_slot (htab, element, 0);
+ if (*slot == EMPTY_ENTRY)
+ return;
+
+ *slot = DELETED_ENTRY;
+ htab->n_deleted++;
}
-/* This function clears a specified slot in a hash table.
- It is useful when you've already done the lookup and don't want to
- do it again. */
+/* This function clears a specified slot in a hash table. It is
+ useful when you've already done the lookup and don't want to do it
+ again. */
void
-clear_hash_table_slot (htab, slot)
- hash_table_t htab;
- hash_table_entry_t *slot;
+htab_clear_slot (htab, slot)
+ htab_t htab;
+ void **slot;
{
if (slot < htab->entries || slot >= htab->entries + htab->size
|| *slot == EMPTY_ENTRY || *slot == DELETED_ENTRY)
abort ();
*slot = DELETED_ENTRY;
- htab->number_of_deleted_elements++;
+ htab->n_deleted++;
}
/* This function scans over the entire hash table calling
argument. */
void
-traverse_hash_table (htab, callback, info)
- hash_table_t htab;
- int (*callback) PARAMS ((hash_table_entry_t, void *));
+htab_traverse (htab, callback, info)
+ htab_t htab;
+ htab_trav callback;
void *info;
{
- hash_table_entry_t *entry_ptr;
- for (entry_ptr = htab->entries; entry_ptr < htab->entries + htab->size;
- entry_ptr++)
- if (*entry_ptr != EMPTY_ENTRY && *entry_ptr != DELETED_ENTRY)
- if (!callback (*entry_ptr, info))
- break;
+ void **slot, **limit;
+ slot = htab->entries;
+ limit = slot + htab->size;
+ do
+ {
+ void *x = *slot;
+ if (x != EMPTY_ENTRY && x != DELETED_ENTRY)
+ if (!(*callback) (x, info))
+ break;
+ }
+ while (++slot < limit);
}
/* The following function returns current size of given hash table. */
size_t
-hash_table_size (htab)
- hash_table_t htab;
+htab_size (htab)
+ htab_t htab;
{
return htab->size;
}
hash table. */
size_t
-hash_table_elements_number (htab)
- hash_table_t htab;
+htab_elements (htab)
+ htab_t htab;
{
- return htab->number_of_elements - htab->number_of_deleted_elements;
+ return htab->n_elements - htab->n_deleted;
}
/* The following function returns number of percents of fixed
collisions during all work with given hash table. */
-int
-hash_table_collisions (htab)
- hash_table_t htab;
+double
+htab_collisions (htab)
+ htab_t htab;
{
int searches;
searches = htab->searches;
if (searches == 0)
- searches++;
- return htab->collisions * 100 / searches;
-}
-
-/* The following function returns number of percents of fixed
- collisions during all work with all hash tables. */
-
-int
-all_hash_table_collisions ()
-{
- int searches;
-
- searches = all_searches;
- if (searches == 0)
- searches++;
- return all_collisions * 100 / searches;
+ return 0.0;
+ return (double)htab->collisions / (double)searches;
}
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