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/** @file include/hash0hash.ic
 The simple hash table utility

 Created 5/20/1997 Heikki Tuuri
 *******************************************************/

#include "ut0rnd.h"

/** Gets the nth cell in a hash table.
 @return pointer to cell */
UNIV_INLINE
hash_cell_t *hash_get_nth_cell(hash_table_t *table, /*!< in: hash table */
                               ulint n)             /*!< in: cell index */
{
  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
  ut_ad(n < table->n_cells);

  return (table->cells + n);
}

/** Clears a hash table so that all the cells become empty. */
UNIV_INLINE
void hash_table_clear(hash_table_t *table) /*!< in/out: hash table */
{
  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
  memset(table->cells, 0x0, table->n_cells * sizeof(*table->cells));
}

/** Returns the number of cells in a hash table.
 @return number of cells */
UNIV_INLINE
ulint hash_get_n_cells(hash_table_t *table) /*!< in: table */
{
  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
  return (table->n_cells);
}

/** Calculates the hash value from a folded value.
 @return hashed value */
UNIV_INLINE
ulint hash_calc_hash(ulint fold,          /*!< in: folded value */
                     hash_table_t *table) /*!< in: hash table */
{
  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
  return (ut_hash_ulint(fold, table->n_cells));
}

#ifndef UNIV_HOTBACKUP
/** Gets the sync object index for a fold value in a hash table.
 @return index */
UNIV_INLINE
ulint hash_get_sync_obj_index(hash_table_t *table, /*!< in: hash table */
                              ulint fold)          /*!< in: fold */
{
  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
  ut_ad(table->type != HASH_TABLE_SYNC_NONE);
  ut_ad(ut_is_2pow(table->n_sync_obj));
  return (ut_2pow_remainder(hash_calc_hash(fold, table), table->n_sync_obj));
}

/** Gets the nth heap in a hash table.
 @return mem heap */
UNIV_INLINE
mem_heap_t *hash_get_nth_heap(hash_table_t *table, /*!< in: hash table */
                              ulint i)             /*!< in: index of the heap */
{
  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
  ut_ad(table->type != HASH_TABLE_SYNC_NONE);
  ut_ad(i < table->n_sync_obj);

  return (table->heaps[i]);
}

/** Gets the heap for a fold value in a hash table.
 @return mem heap */
UNIV_INLINE
mem_heap_t *hash_get_heap(hash_table_t *table, /*!< in: hash table */
                          ulint fold)          /*!< in: fold */
{
  ulint i;

  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);

  if (table->heap) {
    return (table->heap);
  }

  i = hash_get_sync_obj_index(table, fold);

  return (hash_get_nth_heap(table, i));
}

/** Gets the nth mutex in a hash table.
 @return mutex */
UNIV_INLINE
ib_mutex_t *hash_get_nth_mutex(hash_table_t *table, /*!< in: hash table */
                               ulint i) /*!< in: index of the mutex */
{
  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
  ut_ad(table->type == HASH_TABLE_SYNC_MUTEX);
  ut_ad(i < table->n_sync_obj);

  return (table->sync_obj.mutexes + i);
}

/** Gets the mutex for a fold value in a hash table.
 @return mutex */
UNIV_INLINE
ib_mutex_t *hash_get_mutex(hash_table_t *table, /*!< in: hash table */
                           ulint fold)          /*!< in: fold */
{
  ulint i;

  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);

  i = hash_get_sync_obj_index(table, fold);

  return (hash_get_nth_mutex(table, i));
}

/** Gets the nth rw_lock in a hash table.
 @return rw_lock */
UNIV_INLINE
rw_lock_t *hash_get_nth_lock(hash_table_t *table, /*!< in: hash table */
                             ulint i) /*!< in: index of the rw_lock */
{
  ut_ad(table);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);
  ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);
  ut_ad(i < table->n_sync_obj);

  return (table->sync_obj.rw_locks + i);
}

/** Gets the rw_lock for a fold value in a hash table.
 @return rw_lock */
UNIV_INLINE
rw_lock_t *hash_get_lock(hash_table_t *table, /*!< in: hash table */
                         ulint fold)          /*!< in: fold */
{
  ulint i;

  ut_ad(table);
  ut_ad(table->type == HASH_TABLE_SYNC_RW_LOCK);
  ut_ad(table->magic_n == HASH_TABLE_MAGIC_N);

  i = hash_get_sync_obj_index(table, fold);

  return (hash_get_nth_lock(table, i));
}

/** If not appropriate rw_lock for a fold value in a hash table,
relock S-lock the another rw_lock until appropriate for a fold value.
@param[in]	hash_lock	latched rw_lock to be confirmed
@param[in]	table		hash table
@param[in]	fold		fold value
@return	latched rw_lock */
UNIV_INLINE
rw_lock_t *hash_lock_s_confirm(rw_lock_t *hash_lock, hash_table_t *table,
                               ulint fold) {
  ut_ad(rw_lock_own(hash_lock, RW_LOCK_S));

  rw_lock_t *hash_lock_tmp = hash_get_lock(table, fold);

  while (hash_lock_tmp != hash_lock) {
    rw_lock_s_unlock(hash_lock);
    hash_lock = hash_lock_tmp;
    rw_lock_s_lock(hash_lock);
    hash_lock_tmp = hash_get_lock(table, fold);
  }

  return (hash_lock);
}

/** If not appropriate rw_lock for a fold value in a hash table,
relock X-lock the another rw_lock until appropriate for a fold value.
@param[in]	hash_lock	latched rw_lock to be confirmed
@param[in]	table		hash table
@param[in]	fold		fold value
@return	latched rw_lock */
UNIV_INLINE
rw_lock_t *hash_lock_x_confirm(rw_lock_t *hash_lock, hash_table_t *table,
                               ulint fold) {
  ut_ad(rw_lock_own(hash_lock, RW_LOCK_X));

  rw_lock_t *hash_lock_tmp = hash_get_lock(table, fold);

  while (hash_lock_tmp != hash_lock) {
    rw_lock_x_unlock(hash_lock);
    hash_lock = hash_lock_tmp;
    rw_lock_x_lock(hash_lock);
    hash_lock_tmp = hash_get_lock(table, fold);
  }

  return (hash_lock);
}
#endif /* !UNIV_HOTBACKUP */