mariadb/storage/innobase/include/hash0hash.h

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

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Copyright (c) 2018, 2022, MariaDB Corporation.

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this program; if not, write to the Free Software Foundation, Inc.,
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*****************************************************************************/

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

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

#pragma once
#include "ut0rnd.h"
#include "ut0new.h"

struct hash_table_t;
struct hash_cell_t
{
  /** singly-linked, nullptr terminated list of hash buckets */
  void *node;

  /** Append an element.
  @tparam T      type of the element
  @param insert  the being-inserted element
  @param next    the next-element pointer in T */
  template<typename T>
  void append(T &insert, T *T::*next)
  {
    void **after;
    for (after= &node; *after;
         after= reinterpret_cast<void**>(&(static_cast<T*>(*after)->*next)));
    insert.*next= nullptr;
    *after= &insert;
  }

  /** Insert an element after another.
  @tparam T  type of the element
  @param after   the element after which to insert
  @param insert  the being-inserted element
  @param next    the next-element pointer in T */
  template<typename T>
  void insert_after(T &after, T &insert, T *T::*next)
  {
#ifdef UNIV_DEBUG
    for (const T *c= static_cast<const T*>(node); c; c= c->*next)
      if (c == &after)
        goto found;
    ut_error;
  found:
#endif
    insert.*next= after.*next;
    after.*next= &insert;
  }
};

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

#define HASH_INSERT(TYPE, NAME, TABLE, FOLD, DATA)\
do {\
	hash_cell_t*	cell3333;\
	TYPE*		struct3333;\
\
	(DATA)->NAME = NULL;\
\
	cell3333 = &(TABLE)->array[(TABLE)->calc_hash(FOLD)];	\
\
	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;\
\
	cell3333 = &(TABLE)->array[(TABLE)->calc_hash(FOLD)]; \
\
	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) (TABLE)->array[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)\
{\
	(DATA) = (TYPE) HASH_GET_FIRST(TABLE, (TABLE)->calc_hash(FOLD)); \
	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)

/** Hash table with singly-linked overflow lists */
struct hash_table_t
{
  /** number of elements in array (a prime number) */
  ulint n_cells;
  /** the hash array */
  hash_cell_t *array;

  /** Create the hash table.
  @param n  the lower bound of n_cells */
  void create(ulint n)
  {
    n_cells= ut_find_prime(n);
    array= static_cast<hash_cell_t*>(ut_zalloc_nokey(n_cells * sizeof *array));
  }

  /** Clear the hash table. */
  void clear() { memset(array, 0, n_cells * sizeof *array); }

  /** Free the hash table. */
  void free() { ut_free(array); array= nullptr; }

  ulint calc_hash(ulint fold) const { return ut_hash_ulint(fold, n_cells); }
};