php-src/Zend/zend_hash.h

/*
   +----------------------------------------------------------------------+
   | Zend Engine                                                          |
   +----------------------------------------------------------------------+
   | Copyright (c) 1998-2003 Zend Technologies Ltd. (http://www.zend.com) |
   +----------------------------------------------------------------------+
   | This source file is subject to version 2.00 of the Zend license,     |
   | that is bundled with this package in the file LICENSE, and is        | 
   | available at through the world-wide-web at                           |
   | http://www.zend.com/license/2_00.txt.                                |
   | If you did not receive a copy of the Zend license and are unable to  |
   | obtain it through the world-wide-web, please send a note to          |
   | license@zend.com so we can mail you a copy immediately.              |
   +----------------------------------------------------------------------+
   | Authors: Andi Gutmans <andi@zend.com>                                |
   |          Zeev Suraski <zeev@zend.com>                                |
   +----------------------------------------------------------------------+
*/

#ifndef ZEND_HASH_H
#define ZEND_HASH_H

#include <sys/types.h>
#include "zend.h"

#define HASH_KEY_IS_STRING 1
#define HASH_KEY_IS_LONG 2
#define HASH_KEY_NON_EXISTANT 3

#define HASH_UPDATE 		(1<<0)
#define HASH_ADD			(1<<1)
#define HASH_NEXT_INSERT	(1<<2)

#define HASH_DEL_KEY 0
#define HASH_DEL_INDEX 1

typedef ulong (*hash_func_t)(char *arKey, uint nKeyLength);
typedef int  (*compare_func_t)(const void *, const void * TSRMLS_DC);
typedef void (*sort_func_t)(void *, size_t, register size_t, compare_func_t TSRMLS_DC);
typedef void (*dtor_func_t)(void *pDest);
typedef void (*copy_ctor_func_t)(void *pElement);
typedef void (*copy_ctor_param_func_t)(void *pElement, void *pParam);

struct _hashtable;

typedef struct bucket {
	ulong h;						/* Used for numeric indexing */
	uint nKeyLength;
	void *pData;
	void *pDataPtr;
	struct bucket *pListNext;
	struct bucket *pListLast;
	struct bucket *pNext;
	struct bucket *pLast;
	char arKey[1]; /* Must be last element */
} Bucket;

typedef struct _hashtable {
	uint nTableSize;
	uint nTableMask;
	uint nNumOfElements;
	ulong nNextFreeElement;
	Bucket *pInternalPointer;	/* Used for element traversal */
	Bucket *pListHead;
	Bucket *pListTail;
	Bucket **arBuckets;
	dtor_func_t pDestructor;
	zend_bool persistent;
	unsigned char nApplyCount;
	zend_bool bApplyProtection;
#if ZEND_DEBUG
	int inconsistent;
#endif
} HashTable;

typedef Bucket* HashPosition;

BEGIN_EXTERN_C()

/* startup/shutdown */
ZEND_API int _zend_hash_init(HashTable *ht, uint nSize, hash_func_t pHashFunction, dtor_func_t pDestructor, zend_bool persistent ZEND_FILE_LINE_DC);
ZEND_API int _zend_hash_init_ex(HashTable *ht, uint nSize, hash_func_t pHashFunction, dtor_func_t pDestructor, zend_bool persistent, zend_bool bApplyProtection ZEND_FILE_LINE_DC);
ZEND_API void zend_hash_destroy(HashTable *ht);
ZEND_API void zend_hash_clean(HashTable *ht);
#define zend_hash_init(ht, nSize, pHashFunction, pDestructor, persistent)						_zend_hash_init((ht), (nSize), (pHashFunction), (pDestructor), (persistent) ZEND_FILE_LINE_CC)
#define zend_hash_init_ex(ht, nSize, pHashFunction, pDestructor, persistent, bApplyProtection)		_zend_hash_init_ex((ht), (nSize), (pHashFunction), (pDestructor), (persistent), (bApplyProtection) ZEND_FILE_LINE_CC)

/* additions/updates/changes */
ZEND_API int zend_hash_add_or_update(HashTable *ht, char *arKey, uint nKeyLength, void *pData, uint nDataSize, void **pDest, int flag);
#define zend_hash_update(ht, arKey, nKeyLength, pData, nDataSize, pDest) \
		zend_hash_add_or_update(ht, arKey, nKeyLength, pData, nDataSize, pDest, HASH_UPDATE)
#define zend_hash_add(ht, arKey, nKeyLength, pData, nDataSize, pDest) \
		zend_hash_add_or_update(ht, arKey, nKeyLength, pData, nDataSize, pDest, HASH_ADD)

ZEND_API int zend_hash_quick_add_or_update(HashTable *ht, char *arKey, uint nKeyLength, ulong h, void *pData, uint nDataSize, void **pDest, int flag);
#define zend_hash_quick_update(ht, arKey, nKeyLength, h, pData, nDataSize, pDest) \
		zend_hash_quick_add_or_update(ht, arKey, nKeyLength, h, pData, nDataSize, pDest, HASH_UPDATE)
#define zend_hash_quick_add(ht, arKey, nKeyLength, h, pData, nDataSize, pDest) \
		zend_hash_quick_add_or_update(ht, arKey, nKeyLength, h, pData, nDataSize, pDest, HASH_ADD)

ZEND_API int zend_hash_index_update_or_next_insert(HashTable *ht, ulong h, void *pData, uint nDataSize, void **pDest, int flag);
#define zend_hash_index_update(ht, h, pData, nDataSize, pDest) \
		zend_hash_index_update_or_next_insert(ht, h, pData, nDataSize, pDest, HASH_UPDATE)
#define zend_hash_next_index_insert(ht, pData, nDataSize, pDest) \
		zend_hash_index_update_or_next_insert(ht, 0, pData, nDataSize, pDest, HASH_NEXT_INSERT)

ZEND_API int zend_hash_add_empty_element(HashTable *ht, char *arKey, uint nKeyLength);


#define ZEND_HASH_APPLY_KEEP				0
#define ZEND_HASH_APPLY_REMOVE				1<<0
#define ZEND_HASH_APPLY_STOP				1<<1

typedef struct _zend_hash_key {
	char *arKey;
	uint nKeyLength;
	ulong h;
} zend_hash_key;


typedef int (*apply_func_t)(void *pDest TSRMLS_DC);
typedef int (*apply_func_arg_t)(void *pDest, void *argument TSRMLS_DC);
typedef int (*apply_func_args_t)(void *pDest, int num_args, va_list args, zend_hash_key *hash_key);

ZEND_API void zend_hash_graceful_destroy(HashTable *ht);
ZEND_API void zend_hash_graceful_reverse_destroy(HashTable *ht);
ZEND_API void zend_hash_apply(HashTable *ht, apply_func_t apply_func TSRMLS_DC);
ZEND_API void zend_hash_apply_with_argument(HashTable *ht, apply_func_arg_t apply_func, void * TSRMLS_DC);
ZEND_API void zend_hash_apply_with_arguments(HashTable *ht, apply_func_args_t apply_func, int, ...);

/* This function should be used with special care (in other words,
 * it should usually not be used).  When used with the ZEND_HASH_APPLY_STOP
 * return value, it assumes things about the order of the elements in the hash.
 * Also, it does not provide the same kind of reentrancy protection that
 * the standard apply functions do.
 */
ZEND_API void zend_hash_reverse_apply(HashTable *ht, apply_func_t apply_func TSRMLS_DC);


/* Deletes */
ZEND_API int zend_hash_del_key_or_index(HashTable *ht, char *arKey, uint nKeyLength, ulong h, int flag);
#define zend_hash_del(ht, arKey, nKeyLength) \
		zend_hash_del_key_or_index(ht, arKey, nKeyLength, 0, HASH_DEL_KEY)
#define zend_hash_index_del(ht, h) \
		zend_hash_del_key_or_index(ht, NULL, 0, h, HASH_DEL_INDEX)

ZEND_API ulong zend_get_hash_value(HashTable *ht, char *arKey, uint nKeyLength);

/* Data retreival */
ZEND_API int zend_hash_find(HashTable *ht, char *arKey, uint nKeyLength, void **pData);
ZEND_API int zend_hash_quick_find(HashTable *ht, char *arKey, uint nKeyLength, ulong h, void **pData);
ZEND_API int zend_hash_index_find(HashTable *ht, ulong h, void **pData);

/* Misc */
ZEND_API int zend_hash_exists(HashTable *ht, char *arKey, uint nKeyLength);
ZEND_API int zend_hash_index_exists(HashTable *ht, ulong h);
ZEND_API ulong zend_hash_next_free_element(HashTable *ht);

/* traversing */
ZEND_API int zend_hash_move_forward_ex(HashTable *ht, HashPosition *pos);
ZEND_API int zend_hash_move_backwards_ex(HashTable *ht, HashPosition *pos);
ZEND_API int zend_hash_get_current_key_ex(HashTable *ht, char **str_index, uint *str_length, ulong *num_index, zend_bool duplicate, HashPosition *pos);
ZEND_API int zend_hash_get_current_key_type_ex(HashTable *ht, HashPosition *pos);
ZEND_API int zend_hash_get_current_data_ex(HashTable *ht, void **pData, HashPosition *pos);
ZEND_API void zend_hash_internal_pointer_reset_ex(HashTable *ht, HashPosition *pos);
ZEND_API void zend_hash_internal_pointer_end_ex(HashTable *ht, HashPosition *pos);

#define zend_hash_move_forward(ht) \
	zend_hash_move_forward_ex(ht, NULL)
#define zend_hash_move_backwards(ht) \
	zend_hash_move_backwards_ex(ht, NULL)
#define zend_hash_get_current_key(ht, str_index, num_index, duplicate) \
	zend_hash_get_current_key_ex(ht, str_index, NULL, num_index, duplicate, NULL)
#define zend_hash_get_current_key_type(ht) \
	zend_hash_get_current_key_type_ex(ht, NULL)
#define zend_hash_get_current_data(ht, pData) \
	zend_hash_get_current_data_ex(ht, pData, NULL)
#define zend_hash_internal_pointer_reset(ht) \
	zend_hash_internal_pointer_reset_ex(ht, NULL)
#define zend_hash_internal_pointer_end(ht) \
	zend_hash_internal_pointer_end_ex(ht, NULL)

/* Copying, merging and sorting */
ZEND_API void zend_hash_copy(HashTable *target, HashTable *source, copy_ctor_func_t pCopyConstructor, void *tmp, uint size);
ZEND_API void zend_hash_merge(HashTable *target, HashTable *source, copy_ctor_func_t pCopyConstructor, void *tmp, uint size, int overwrite);
ZEND_API void zend_hash_merge_ex(HashTable *target, HashTable *source, copy_ctor_func_t pCopyConstructor, uint size, zend_bool (*pReplaceOrig)(void *orig, void *p_new));
ZEND_API int zend_hash_sort(HashTable *ht, sort_func_t sort_func, compare_func_t compare_func, int renumber TSRMLS_DC);
ZEND_API int zend_hash_compare(HashTable *ht1, HashTable *ht2, compare_func_t compar, zend_bool ordered TSRMLS_DC);
ZEND_API int zend_hash_minmax(HashTable *ht, compare_func_t compar, int flag, void **pData TSRMLS_DC);

ZEND_API int zend_hash_num_elements(HashTable *ht);

ZEND_API int zend_hash_rehash(HashTable *ht);

/*
 * DJBX33A (Daniel J. Bernstein, Times 33 with Addition)
 *
 * This is Daniel J. Bernstein's popular `times 33' hash function as
 * posted by him years ago on comp.lang.c. It basically uses a function
 * like ``hash(i) = hash(i-1) * 33 + str[i]''. This is one of the best
 * known hash functions for strings. Because it is both computed very
 * fast and distributes very well.
 *
 * The magic of number 33, i.e. why it works better than many other
 * constants, prime or not, has never been adequately explained by
 * anyone. So I try an explanation: if one experimentally tests all
 * multipliers between 1 and 256 (as RSE did now) one detects that even
 * numbers are not useable at all. The remaining 128 odd numbers
 * (except for the number 1) work more or less all equally well. They
 * all distribute in an acceptable way and this way fill a hash table
 * with an average percent of approx. 86%. 
 *
 * If one compares the Chi^2 values of the variants, the number 33 not
 * even has the best value. But the number 33 and a few other equally
 * good numbers like 17, 31, 63, 127 and 129 have nevertheless a great
 * advantage to the remaining numbers in the large set of possible
 * multipliers: their multiply operation can be replaced by a faster
 * operation based on just one shift plus either a single addition
 * or subtraction operation. And because a hash function has to both
 * distribute good _and_ has to be very fast to compute, those few
 * numbers should be preferred and seems to be the reason why Daniel J.
 * Bernstein also preferred it.
 *
 *
 *                  -- Ralf S. Engelschall <rse@engelschall.com>
 */

static inline ulong zend_inline_hash_func(char *arKey, uint nKeyLength)
{
	register ulong hash = 5381;

	/* variant with the hash unrolled eight times */
	for (; nKeyLength >= 8; nKeyLength -= 8) {
		hash = ((hash << 5) + hash) + *arKey++;
		hash = ((hash << 5) + hash) + *arKey++;
		hash = ((hash << 5) + hash) + *arKey++;
		hash = ((hash << 5) + hash) + *arKey++;
		hash = ((hash << 5) + hash) + *arKey++;
		hash = ((hash << 5) + hash) + *arKey++;
		hash = ((hash << 5) + hash) + *arKey++;
		hash = ((hash << 5) + hash) + *arKey++;
	}
	switch (nKeyLength) {
		case 7: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */
		case 6: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */
		case 5: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */
		case 4: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */
		case 3: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */
		case 2: hash = ((hash << 5) + hash) + *arKey++; /* fallthrough... */
		case 1: hash = ((hash << 5) + hash) + *arKey++; break;
		case 0: break;
EMPTY_SWITCH_DEFAULT_CASE()
	}
	return hash;
}


ZEND_API ulong zend_hash_func(char *arKey, uint nKeyLength);

#if ZEND_DEBUG
/* debug */
void zend_hash_display_pListTail(HashTable *ht);
void zend_hash_display(HashTable *ht);
#endif

END_EXTERN_C()

#define ZEND_INIT_SYMTABLE(ht)								\
	ZEND_INIT_SYMTABLE_EX(ht, 2, 0)

#define ZEND_INIT_SYMTABLE_EX(ht, n, persistent)			\
	zend_hash_init(ht, n, NULL, ZVAL_PTR_DTOR, persistent)


#endif							/* ZEND_HASH_H */