/*****************************************************************************

Copyright (c) 1997, 2021, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License, version 2.0,
as published by the Free Software Foundation.

This program is also distributed with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
documentation.  The authors of MySQL hereby grant you an additional
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but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License, version 2.0, for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

*****************************************************************************/

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

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

#ifndef hash0hash_h
#define hash0hash_h

#include "univ.i"
#include "mem0mem.h"
#ifndef UNIV_HOTBACKUP
# include "sync0rw.h"
#endif /* !UNIV_HOTBACKUP */

struct hash_table_t;
struct hash_cell_t;

typedef void*	hash_node_t;

/* Fix Bug #13859: symbol collision between imap/mysql */
#define hash_create hash0_create

/* Differnt types of hash_table based on the synchronization
method used for it. */
enum hash_table_sync_t {
	HASH_TABLE_SYNC_NONE = 0,	/*!< Don't use any internal
					synchronization objects for
					this hash_table. */
	HASH_TABLE_SYNC_MUTEX,		/*!< Use mutexes to control
					access to this hash_table. */
	HASH_TABLE_SYNC_RW_LOCK		/*!< Use rw_locks to control
					access to this hash_table. */
};

/*************************************************************//**
Creates a hash table with >= n array cells. The actual number
of cells is chosen to be a prime number slightly bigger than n.
@return own: created table */
hash_table_t*
hash_create(
/*========*/
	ulint	n);	/*!< in: number of array cells */
#ifndef UNIV_HOTBACKUP
/*************************************************************//**
Creates a sync object array array to protect a hash table.
::sync_obj can be mutexes or rw_locks depening on the type of
hash table. */
void
hash_create_sync_obj(
/*=================*/
	hash_table_t*		table,	/*!< in: hash table */
	hash_table_sync_t	type,	/*!< in: HASH_TABLE_SYNC_MUTEX
					or HASH_TABLE_SYNC_RW_LOCK */
	latch_id_t		id,	/*!< in: mutex/rw_lock ID */
	ulint			n_sync_obj);/*!< in: number of sync objects,
					must be a power of 2 */
#endif /* !UNIV_HOTBACKUP */

/*************************************************************//**
Frees a hash table. */
void
hash_table_free(
/*============*/
	hash_table_t*	table);	/*!< in, own: hash table */
/**************************************************************//**
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 */
#ifndef UNIV_HOTBACKUP
/********************************************************************//**
Assert that the mutex for the table is held */
# define HASH_ASSERT_OWN(TABLE, FOLD)				\
	ut_ad((TABLE)->type != HASH_TABLE_SYNC_MUTEX		\
	      || (mutex_own(hash_get_mutex((TABLE), FOLD))));
#else /* !UNIV_HOTBACKUP */
# define HASH_ASSERT_OWN(TABLE, FOLD)
#endif /* !UNIV_HOTBACKUP */

/*******************************************************************//**
Inserts a struct to a hash table. */

#define HASH_INSERT(TYPE, NAME, TABLE, FOLD, DATA)\
do {\
	hash_cell_t*	cell3333;\
	TYPE*		struct3333;\
\
	HASH_ASSERT_OWN(TABLE, FOLD)\
\
	(DATA)->NAME = NULL;\
\
	cell3333 = hash_get_nth_cell(TABLE, hash_calc_hash(FOLD, TABLE));\
\
	if (cell3333->node == NULL) {\
		cell3333->node = DATA;\
	} else {\
		struct3333 = (TYPE*) cell3333->node;\
\
		while (struct3333->NAME != NULL) {\
\
			struct3333 = (TYPE*) struct3333->NAME;\
		}\
\
		struct3333->NAME = DATA;\
	}\
} while (0)

#ifdef UNIV_HASH_DEBUG
# define HASH_ASSERT_VALID(DATA) ut_a((void*) (DATA) != (void*) -1)
# define HASH_INVALIDATE(DATA, NAME) *(void**) (&DATA->NAME) = (void*) -1
#else
# define HASH_ASSERT_VALID(DATA) do {} while (0)
# define HASH_INVALIDATE(DATA, NAME) do {} while (0)
#endif

/*******************************************************************//**
Deletes a struct from a hash table. */

#define HASH_DELETE(TYPE, NAME, TABLE, FOLD, DATA)\
do {\
	hash_cell_t*	cell3333;\
	TYPE*		struct3333;\
\
	HASH_ASSERT_OWN(TABLE, FOLD)\
\
	cell3333 = hash_get_nth_cell(TABLE, hash_calc_hash(FOLD, TABLE));\
\
	if (cell3333->node == DATA) {\
		HASH_ASSERT_VALID(DATA->NAME);\
		cell3333->node = DATA->NAME;\
	} else {\
		struct3333 = (TYPE*) cell3333->node;\
\
		while (struct3333->NAME != DATA) {\
\
			struct3333 = (TYPE*) struct3333->NAME;\
			ut_a(struct3333);\
		}\
\
		struct3333->NAME = DATA->NAME;\
	}\
	HASH_INVALIDATE(DATA, NAME);\
} while (0)

/*******************************************************************//**
Gets the first struct in a hash chain, NULL if none. */

#define HASH_GET_FIRST(TABLE, HASH_VAL)\
	(hash_get_nth_cell(TABLE, HASH_VAL)->node)

/*******************************************************************//**
Gets the next struct in a hash chain, NULL if none. */

#define HASH_GET_NEXT(NAME, DATA)	((DATA)->NAME)

/********************************************************************//**
Looks for a struct in a hash table. */
#define HASH_SEARCH(NAME, TABLE, FOLD, TYPE, DATA, ASSERTION, TEST)\
{\
\
	HASH_ASSERT_OWN(TABLE, FOLD)\
\
	(DATA) = (TYPE) HASH_GET_FIRST(TABLE, hash_calc_hash(FOLD, TABLE));\
	HASH_ASSERT_VALID(DATA);\
\
	while ((DATA) != NULL) {\
		ASSERTION;\
		if (TEST) {\
			break;\
		} else {\
			HASH_ASSERT_VALID(HASH_GET_NEXT(NAME, DATA));\
			(DATA) = (TYPE) HASH_GET_NEXT(NAME, DATA);\
		}\
	}\
}

/********************************************************************//**
Looks for an item in all hash buckets. */
#define HASH_SEARCH_ALL(NAME, TABLE, TYPE, DATA, ASSERTION, TEST)	\
do {									\
	ulint	i3333;							\
									\
	for (i3333 = (TABLE)->n_cells; i3333--; ) {			\
		(DATA) = (TYPE) HASH_GET_FIRST(TABLE, i3333);		\
									\
		while ((DATA) != NULL) {				\
			HASH_ASSERT_VALID(DATA);			\
			ASSERTION;					\
									\
			if (TEST) {					\
				break;					\
			}						\
									\
			(DATA) = (TYPE) HASH_GET_NEXT(NAME, DATA);	\
		}							\
									\
		if ((DATA) != NULL) {					\
			break;						\
		}							\
	}								\
} while (0)

/************************************************************//**
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 */

/*************************************************************//**
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 */

/*************************************************************//**
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 */
/*******************************************************************//**
Deletes a struct which is stored in the heap of the hash table, and compacts
the heap. The fold value must be stored in the struct NODE in a field named
'fold'. */

#define HASH_DELETE_AND_COMPACT(TYPE, NAME, TABLE, NODE)\
do {\
	TYPE*		node111;\
	TYPE*		top_node111;\
	hash_cell_t*	cell111;\
	ulint		fold111;\
\
	fold111 = (NODE)->fold;\
\
	HASH_DELETE(TYPE, NAME, TABLE, fold111, NODE);\
\
	top_node111 = (TYPE*) mem_heap_get_top(\
				hash_get_heap(TABLE, fold111),\
							sizeof(TYPE));\
\
	/* If the node to remove is not the top node in the heap, compact the\
	heap of nodes by moving the top node in the place of NODE. */\
\
	if (NODE != top_node111) {\
\
		/* Copy the top node in place of NODE */\
\
		*(NODE) = *top_node111;\
\
		cell111 = hash_get_nth_cell(TABLE,\
				hash_calc_hash(top_node111->fold, TABLE));\
\
		/* Look for the pointer to the top node, to update it */\
\
		if (cell111->node == top_node111) {\
			/* The top node is the first in the chain */\
\
			cell111->node = NODE;\
		} else {\
			/* We have to look for the predecessor of the top\
			node */\
			node111 = static_cast<TYPE*>(cell111->node);\
\
			while (top_node111 != HASH_GET_NEXT(NAME, node111)) {\
\
				node111 = static_cast<TYPE*>(\
					HASH_GET_NEXT(NAME, node111));\
			}\
\
			/* Now we have the predecessor node */\
\
			node111->NAME = NODE;\
		}\
	}\
\
	/* Free the space occupied by the top node */\
\
	mem_heap_free_top(hash_get_heap(TABLE, fold111), sizeof(TYPE));\
} while (0)

#ifndef UNIV_HOTBACKUP
/****************************************************************//**
Move all hash table entries from OLD_TABLE to NEW_TABLE. */

#define HASH_MIGRATE(OLD_TABLE, NEW_TABLE, NODE_TYPE, PTR_NAME, FOLD_FUNC) \
do {\
	ulint		i2222;\
	ulint		cell_count2222;\
\
	cell_count2222 = hash_get_n_cells(OLD_TABLE);\
\
	for (i2222 = 0; i2222 < cell_count2222; i2222++) {\
		NODE_TYPE*	node2222 = static_cast<NODE_TYPE*>(\
			HASH_GET_FIRST((OLD_TABLE), i2222));\
\
		while (node2222) {\
			NODE_TYPE*	next2222 = static_cast<NODE_TYPE*>(\
				node2222->PTR_NAME);\
			ulint		fold2222 = FOLD_FUNC(node2222);\
\
			HASH_INSERT(NODE_TYPE, PTR_NAME, (NEW_TABLE),\
				fold2222, node2222);\
\
			node2222 = next2222;\
		}\
	}\
} while (0)

/************************************************************//**
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 */
/************************************************************//**
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 */
/************************************************************//**
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 */
/************************************************************//**
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 */
/************************************************************//**
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 */
/************************************************************//**
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 */
/************************************************************//**
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 */

/** 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);

/** 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);

/************************************************************//**
Reserves the mutex for a fold value in a hash table. */
void
hash_mutex_enter(
/*=============*/
	hash_table_t*	table,	/*!< in: hash table */
	ulint		fold);	/*!< in: fold */
/************************************************************//**
Releases the mutex for a fold value in a hash table. */
void
hash_mutex_exit(
/*============*/
	hash_table_t*	table,	/*!< in: hash table */
	ulint		fold);	/*!< in: fold */
/************************************************************//**
Reserves all the mutexes of a hash table, in an ascending order. */
void
hash_mutex_enter_all(
/*=================*/
	hash_table_t*	table);	/*!< in: hash table */
/************************************************************//**
Releases all the mutexes of a hash table. */
void
hash_mutex_exit_all(
/*================*/
	hash_table_t*	table);	/*!< in: hash table */
/************************************************************//**
Releases all but the passed in mutex of a hash table. */
void
hash_mutex_exit_all_but(
/*====================*/
	hash_table_t*	table,		/*!< in: hash table */
	ib_mutex_t*	keep_mutex);	/*!< in: mutex to keep */
/************************************************************//**
s-lock a lock for a fold value in a hash table. */
void
hash_lock_s(
/*========*/
	hash_table_t*	table,	/*!< in: hash table */
	ulint		fold);	/*!< in: fold */
/************************************************************//**
x-lock a lock for a fold value in a hash table. */
void
hash_lock_x(
/*========*/
	hash_table_t*	table,	/*!< in: hash table */
	ulint		fold);	/*!< in: fold */
/************************************************************//**
unlock an s-lock for a fold value in a hash table. */
void
hash_unlock_s(
/*==========*/

	hash_table_t*	table,	/*!< in: hash table */
	ulint		fold);	/*!< in: fold */
/************************************************************//**
unlock x-lock for a fold value in a hash table. */
void
hash_unlock_x(
/*==========*/
	hash_table_t*	table,	/*!< in: hash table */
	ulint		fold);	/*!< in: fold */
/************************************************************//**
Reserves all the locks of a hash table, in an ascending order. */
void
hash_lock_x_all(
/*============*/
	hash_table_t*	table);	/*!< in: hash table */
/************************************************************//**
Releases all the locks of a hash table, in an ascending order. */
void
hash_unlock_x_all(
/*==============*/
	hash_table_t*	table);	/*!< in: hash table */
/************************************************************//**
Releases all but passed in lock of a hash table, */
void
hash_unlock_x_all_but(
/*==================*/
	hash_table_t*	table,		/*!< in: hash table */
	rw_lock_t*	keep_lock);	/*!< in: lock to keep */

#else /* !UNIV_HOTBACKUP */
# define hash_get_heap(table, fold)	((table)->heap)
# define hash_mutex_enter(table, fold)	((void) 0)
# define hash_mutex_exit(table, fold)	((void) 0)
# define hash_mutex_enter_all(table)	((void) 0)
# define hash_mutex_exit_all(table)	((void) 0)
# define hash_mutex_exit_all_but(t, m)	((void) 0)
# define hash_lock_s(t, f)		((void) 0)
# define hash_lock_x(t, f)		((void) 0)
# define hash_unlock_s(t, f)		((void) 0)
# define hash_unlock_x(t, f)		((void) 0)
# define hash_lock_x_all(t)		((void) 0)
# define hash_unlock_x_all(t)		((void) 0)
# define hash_unlock_x_all_but(t, l)	((void) 0)
#endif /* !UNIV_HOTBACKUP */

struct hash_cell_t{
	void*	node;	/*!< hash chain node, NULL if none */
};

/* The hash table structure */
struct hash_table_t {
	enum hash_table_sync_t	type;	/*<! type of hash_table. */
#if defined UNIV_AHI_DEBUG || defined UNIV_DEBUG
# ifndef UNIV_HOTBACKUP
	ibool			adaptive;/* TRUE if this is the hash
					table of the adaptive hash
					index */
# endif /* !UNIV_HOTBACKUP */
#endif /* UNIV_AHI_DEBUG || UNIV_DEBUG */
	ulint			n_cells;/* number of cells in the hash table */
	hash_cell_t*		array;	/*!< pointer to cell array */
#ifndef UNIV_HOTBACKUP
	ulint			n_sync_obj;/* if sync_objs != NULL, then
					the number of either the number
					of mutexes or the number of
					rw_locks depending on the type.
					Must be a power of 2 */
	union {
		ib_mutex_t*	mutexes;/* NULL, or an array of mutexes
					used to protect segments of the
					hash table */
		rw_lock_t*	rw_locks;/* NULL, or an array of rw_lcoks
					used to protect segments of the
					hash table */
	} sync_obj;

	mem_heap_t**		heaps;	/*!< if this is non-NULL, hash
					chain nodes for external chaining
					can be allocated from these memory
					heaps; there are then n_mutexes
					many of these heaps */
#endif /* !UNIV_HOTBACKUP */
	mem_heap_t*		heap;
#ifdef UNIV_DEBUG
	ulint			magic_n;
# define HASH_TABLE_MAGIC_N	76561114
#endif /* UNIV_DEBUG */
};

#ifndef UNIV_NONINL
#include "hash0hash.ic"
#endif

#endif
