dist/include/apr_hash.h

/* Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef APR_HASH_H
#define APR_HASH_H

/**
 * @file apr_hash.h
 * @brief APR Hash Tables
 */

#include "apr_pools.h"

#ifdef __cplusplus
extern "C" {
#endif

/**
 * @defgroup apr_hash Hash Tables
 * @ingroup APR 
 * @{
 */

/**
 * When passing a key to apr_hash_set or apr_hash_get, this value can be
 * passed to indicate a string-valued key, and have apr_hash compute the
 * length automatically.
 *
 * @remark apr_hash will use strlen(key) for the length. The NUL terminator
 *         is not included in the hash value (why throw a constant in?).
 *         Since the hash table merely references the provided key (rather
 *         than copying it), apr_hash_this() will return the NUL-term'd key.
 */
#define APR_HASH_KEY_STRING     (-1)

/**
 * Abstract type for hash tables.
 */
typedef struct apr_hash_t apr_hash_t;

/**
 * Abstract type for scanning hash tables.
 */
typedef struct apr_hash_index_t apr_hash_index_t;

/**
 * Callback functions for calculating hash values.
 * @param key The key.
 * @param klen The length of the key, or APR_HASH_KEY_STRING to use the string 
 *             length. If APR_HASH_KEY_STRING then returns the actual key length.
 */
typedef unsigned int (*apr_hashfunc_t)(const char *key, apr_ssize_t *klen);

/**
 * The default hash function.
 */
APR_DECLARE_NONSTD(unsigned int) apr_hashfunc_default(const char *key,
                                                      apr_ssize_t *klen);

/**
 * Create a hash table.
 * @param pool The pool to allocate the hash table out of
 * @return The hash table just created
  */
APR_DECLARE(apr_hash_t *) apr_hash_make(apr_pool_t *pool);

/**
 * Create a hash table with a custom hash function
 * @param pool The pool to allocate the hash table out of
 * @param hash_func A custom hash function.
 * @return The hash table just created
  */
APR_DECLARE(apr_hash_t *) apr_hash_make_custom(apr_pool_t *pool, 
                                               apr_hashfunc_t hash_func);

/**
 * Make a copy of a hash table
 * @param pool The pool from which to allocate the new hash table
 * @param h The hash table to clone
 * @return The hash table just created
 * @remark Makes a shallow copy
 */
APR_DECLARE(apr_hash_t *) apr_hash_copy(apr_pool_t *pool,
                                        const apr_hash_t *h);

/**
 * Associate a value with a key in a hash table.
 * @param ht The hash table
 * @param key Pointer to the key
 * @param klen Length of the key. Can be APR_HASH_KEY_STRING to use the string length.
 * @param val Value to associate with the key
 * @remark If the value is NULL the hash entry is deleted.
 */
APR_DECLARE(void) apr_hash_set(apr_hash_t *ht, const void *key,
                               apr_ssize_t klen, const void *val);

/**
 * Look up the value associated with a key in a hash table.
 * @param ht The hash table
 * @param key Pointer to the key
 * @param klen Length of the key. Can be APR_HASH_KEY_STRING to use the string length.
 * @return Returns NULL if the key is not present.
 */
APR_DECLARE(void *) apr_hash_get(apr_hash_t *ht, const void *key,
                                 apr_ssize_t klen);

/**
 * Start iterating over the entries in a hash table.
 * @param p The pool to allocate the apr_hash_index_t iterator. If this
 *          pool is NULL, then an internal, non-thread-safe iterator is used.
 * @param ht The hash table
 * @return The iteration state
 * @remark  There is no restriction on adding or deleting hash entries during
 * an iteration (although the results may be unpredictable unless all you do
 * is delete the current entry) and multiple iterations can be in
 * progress at the same time.
 *
 * @par Example:
 *
 * @code
 * int sum_values(apr_pool_t *p, apr_hash_t *ht)
 * {
 *     apr_hash_index_t *hi;
 *     void *val;
 *     int sum = 0;
 *     for (hi = apr_hash_first(p, ht); hi; hi = apr_hash_next(hi)) {
 *         apr_hash_this(hi, NULL, NULL, &val);
 *         sum += *(int *)val;
 *     }
 *     return sum;
 * }
 * @endcode
 */
APR_DECLARE(apr_hash_index_t *) apr_hash_first(apr_pool_t *p, apr_hash_t *ht);

/**
 * Continue iterating over the entries in a hash table.
 * @param hi The iteration state
 * @return a pointer to the updated iteration state.  NULL if there are no more  
 *         entries.
 */
APR_DECLARE(apr_hash_index_t *) apr_hash_next(apr_hash_index_t *hi);

/**
 * Get the current entry's details from the iteration state.
 * @param hi The iteration state
 * @param key Return pointer for the pointer to the key.
 * @param klen Return pointer for the key length.
 * @param val Return pointer for the associated value.
 * @remark The return pointers should point to a variable that will be set to the
 *         corresponding data, or they may be NULL if the data isn't interesting.
 */
APR_DECLARE(void) apr_hash_this(apr_hash_index_t *hi, const void **key, 
                                apr_ssize_t *klen, void **val);

/**
 * Get the current entry's key from the iteration state.
 * @param hi The iteration state
 * @return The pointer to the key
 */
APR_DECLARE(const void*) apr_hash_this_key(apr_hash_index_t *hi);

/**
 * Get the current entry's key length from the iteration state.
 * @param hi The iteration state
 * @return The key length
 */
APR_DECLARE(apr_ssize_t) apr_hash_this_key_len(apr_hash_index_t *hi);

/**
 * Get the current entry's value from the iteration state.
 * @param hi The iteration state
 * @return The pointer to the value
 */
APR_DECLARE(void*) apr_hash_this_val(apr_hash_index_t *hi);

/**
 * Get the number of key/value pairs in the hash table.
 * @param ht The hash table
 * @return The number of key/value pairs in the hash table.
 */
APR_DECLARE(unsigned int) apr_hash_count(apr_hash_t *ht);

/**
 * Clear any key/value pairs in the hash table.
 * @param ht The hash table
 */
APR_DECLARE(void) apr_hash_clear(apr_hash_t *ht);

/**
 * Merge two hash tables into one new hash table. The values of the overlay
 * hash override the values of the base if both have the same key.  Both
 * hash tables must use the same hash function.
 * @param p The pool to use for the new hash table
 * @param overlay The table to add to the initial table
 * @param base The table that represents the initial values of the new table
 * @return A new hash table containing all of the data from the two passed in
 */
APR_DECLARE(apr_hash_t *) apr_hash_overlay(apr_pool_t *p,
                                           const apr_hash_t *overlay, 
                                           const apr_hash_t *base);

/**
 * Merge two hash tables into one new hash table. If the same key
 * is present in both tables, call the supplied merge function to
 * produce a merged value for the key in the new table.  Both
 * hash tables must use the same hash function.
 * @param p The pool to use for the new hash table
 * @param h1 The first of the tables to merge
 * @param h2 The second of the tables to merge
 * @param merger A callback function to merge values, or NULL to
 *  make values from h1 override values from h2 (same semantics as
 *  apr_hash_overlay())
 * @param data Client data to pass to the merger function
 * @return A new hash table containing all of the data from the two passed in
 */
APR_DECLARE(apr_hash_t *) apr_hash_merge(apr_pool_t *p,
                                         const apr_hash_t *h1,
                                         const apr_hash_t *h2,
                                         void * (*merger)(apr_pool_t *p,
                                                     const void *key,
                                                     apr_ssize_t klen,
                                                     const void *h1_val,
                                                     const void *h2_val,
                                                     const void *data),
                                         const void *data);

/**
 * Declaration prototype for the iterator callback function of apr_hash_do().
 *
 * @param rec The data passed as the first argument to apr_hash_[v]do()
 * @param key The key from this iteration of the hash table
 * @param klen The key length from this iteration of the hash table
 * @param value The value from this iteration of the hash table
 * @remark Iteration continues while this callback function returns non-zero.
 * To export the callback function for apr_hash_do() it must be declared 
 * in the _NONSTD convention.
 */
typedef int (apr_hash_do_callback_fn_t)(void *rec, const void *key,
                                                   apr_ssize_t klen,
                                                   const void *value);

/** 
 * Iterate over a hash table running the provided function once for every
 * element in the hash table. The @param comp function will be invoked for
 * every element in the hash table.
 *
 * @param comp The function to run
 * @param rec The data to pass as the first argument to the function
 * @param ht The hash table to iterate over
 * @return FALSE if one of the comp() iterations returned zero; TRUE if all
 *            iterations returned non-zero
 * @see apr_hash_do_callback_fn_t
 */
APR_DECLARE(int) apr_hash_do(apr_hash_do_callback_fn_t *comp,
                             void *rec, const apr_hash_t *ht);

/**
 * Get a pointer to the pool which the hash table was created in
 */
APR_POOL_DECLARE_ACCESSOR(hash);

/** @} */

#ifdef __cplusplus
}
#endif

#endif  /* !APR_HASH_H */
Revision:	9273
Committed:	Mon Feb 20 03:07:37 2017 UTC (7 years, 2 months ago) by laffer1
Content type:	text/plain
File size:	10219 byte(s)
Log Message:	update apr to 1.5.2.
#	Content
1	/* Licensed to the Apache Software Foundation (ASF) under one or more
2	* contributor license agreements. See the NOTICE file distributed with
3	* this work for additional information regarding copyright ownership.
4	* The ASF licenses this file to You under the Apache License, Version 2.0
5	* (the "License"); you may not use this file except in compliance with
6	* the License. You may obtain a copy of the License at
7	*
8	* http://www.apache.org/licenses/LICENSE-2.0
9	*
10	* Unless required by applicable law or agreed to in writing, software
11	* distributed under the License is distributed on an "AS IS" BASIS,
12	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13	* See the License for the specific language governing permissions and
14	* limitations under the License.
15	*/
16
17	#ifndef APR_HASH_H
18	#define APR_HASH_H
19
20	/**
21	* @file apr_hash.h
22	* @brief APR Hash Tables
23	*/
24
25	#include "apr_pools.h"
26
27	#ifdef __cplusplus
28	extern "C" {
29	#endif
30
31	/**
32	* @defgroup apr_hash Hash Tables
33	* @ingroup APR
34	* @{
35	*/
36
37	/**
38	* When passing a key to apr_hash_set or apr_hash_get, this value can be
39	* passed to indicate a string-valued key, and have apr_hash compute the
40	* length automatically.
41	*
42	* @remark apr_hash will use strlen(key) for the length. The NUL terminator
43	* is not included in the hash value (why throw a constant in?).
44	* Since the hash table merely references the provided key (rather
45	* than copying it), apr_hash_this() will return the NUL-term'd key.
46	*/
47	#define APR_HASH_KEY_STRING (-1)
48
49	/**
50	* Abstract type for hash tables.
51	*/
52	typedef struct apr_hash_t apr_hash_t;
53
54	/**
55	* Abstract type for scanning hash tables.
56	*/
57	typedef struct apr_hash_index_t apr_hash_index_t;
58
59	/**
60	* Callback functions for calculating hash values.
61	* @param key The key.
62	* @param klen The length of the key, or APR_HASH_KEY_STRING to use the string
63	* length. If APR_HASH_KEY_STRING then returns the actual key length.
64	*/
65	typedef unsigned int (apr_hashfunc_t)(const char key, apr_ssize_t *klen);
66
67	/**
68	* The default hash function.
69	*/
70	APR_DECLARE_NONSTD(unsigned int) apr_hashfunc_default(const char *key,
71	apr_ssize_t *klen);
72
73	/**
74	* Create a hash table.
75	* @param pool The pool to allocate the hash table out of
76	* @return The hash table just created
77	*/
78	APR_DECLARE(apr_hash_t ) apr_hash_make(apr_pool_t pool);
79
80	/**
81	* Create a hash table with a custom hash function
82	* @param pool The pool to allocate the hash table out of
83	* @param hash_func A custom hash function.
84	* @return The hash table just created
85	*/
86	APR_DECLARE(apr_hash_t ) apr_hash_make_custom(apr_pool_t pool,
87	apr_hashfunc_t hash_func);
88
89	/**
90	* Make a copy of a hash table
91	* @param pool The pool from which to allocate the new hash table
92	* @param h The hash table to clone
93	* @return The hash table just created
94	* @remark Makes a shallow copy
95	*/
96	APR_DECLARE(apr_hash_t ) apr_hash_copy(apr_pool_t pool,
97	const apr_hash_t *h);
98
99	/**
100	* Associate a value with a key in a hash table.
101	* @param ht The hash table
102	* @param key Pointer to the key
103	* @param klen Length of the key. Can be APR_HASH_KEY_STRING to use the string length.
104	* @param val Value to associate with the key
105	* @remark If the value is NULL the hash entry is deleted.
106	*/
107	APR_DECLARE(void) apr_hash_set(apr_hash_t ht, const void key,
108	apr_ssize_t klen, const void *val);
109
110	/**
111	* Look up the value associated with a key in a hash table.
112	* @param ht The hash table
113	* @param key Pointer to the key
114	* @param klen Length of the key. Can be APR_HASH_KEY_STRING to use the string length.
115	* @return Returns NULL if the key is not present.
116	*/
117	APR_DECLARE(void ) apr_hash_get(apr_hash_t ht, const void *key,
118	apr_ssize_t klen);
119
120	/**
121	* Start iterating over the entries in a hash table.
122	* @param p The pool to allocate the apr_hash_index_t iterator. If this
123	* pool is NULL, then an internal, non-thread-safe iterator is used.
124	* @param ht The hash table
125	* @return The iteration state
126	* @remark There is no restriction on adding or deleting hash entries during
127	* an iteration (although the results may be unpredictable unless all you do
128	* is delete the current entry) and multiple iterations can be in
129	* progress at the same time.
130	*
131	* @par Example:
132	*
133	* @code
134	* int sum_values(apr_pool_t p, apr_hash_t ht)
135	* {
136	* apr_hash_index_t *hi;
137	* void *val;
138	* int sum = 0;
139	* for (hi = apr_hash_first(p, ht); hi; hi = apr_hash_next(hi)) {
140	* apr_hash_this(hi, NULL, NULL, &val);
141	* sum += (int )val;
142	* }
143	* return sum;
144	* }
145	* @endcode
146	*/
147	APR_DECLARE(apr_hash_index_t ) apr_hash_first(apr_pool_t p, apr_hash_t *ht);
148
149	/**
150	* Continue iterating over the entries in a hash table.
151	* @param hi The iteration state
152	* @return a pointer to the updated iteration state. NULL if there are no more
153	* entries.
154	*/
155	APR_DECLARE(apr_hash_index_t ) apr_hash_next(apr_hash_index_t hi);
156
157	/**
158	* Get the current entry's details from the iteration state.
159	* @param hi The iteration state
160	* @param key Return pointer for the pointer to the key.
161	* @param klen Return pointer for the key length.
162	* @param val Return pointer for the associated value.
163	* @remark The return pointers should point to a variable that will be set to the
164	* corresponding data, or they may be NULL if the data isn't interesting.
165	*/
166	APR_DECLARE(void) apr_hash_this(apr_hash_index_t hi, const void *key,
167	apr_ssize_t klen, void *val);
168
169	/**
170	* Get the current entry's key from the iteration state.
171	* @param hi The iteration state
172	* @return The pointer to the key
173	*/
174	APR_DECLARE(const void) apr_hash_this_key(apr_hash_index_t hi);
175
176	/**
177	* Get the current entry's key length from the iteration state.
178	* @param hi The iteration state
179	* @return The key length
180	*/
181	APR_DECLARE(apr_ssize_t) apr_hash_this_key_len(apr_hash_index_t *hi);
182
183	/**
184	* Get the current entry's value from the iteration state.
185	* @param hi The iteration state
186	* @return The pointer to the value
187	*/
188	APR_DECLARE(void) apr_hash_this_val(apr_hash_index_t hi);
189
190	/**
191	* Get the number of key/value pairs in the hash table.
192	* @param ht The hash table
193	* @return The number of key/value pairs in the hash table.
194	*/
195	APR_DECLARE(unsigned int) apr_hash_count(apr_hash_t *ht);
196
197	/**
198	* Clear any key/value pairs in the hash table.
199	* @param ht The hash table
200	*/
201	APR_DECLARE(void) apr_hash_clear(apr_hash_t *ht);
202
203	/**
204	* Merge two hash tables into one new hash table. The values of the overlay
205	* hash override the values of the base if both have the same key. Both
206	* hash tables must use the same hash function.
207	* @param p The pool to use for the new hash table
208	* @param overlay The table to add to the initial table
209	* @param base The table that represents the initial values of the new table
210	* @return A new hash table containing all of the data from the two passed in
211	*/
212	APR_DECLARE(apr_hash_t ) apr_hash_overlay(apr_pool_t p,
213	const apr_hash_t *overlay,
214	const apr_hash_t *base);
215
216	/**
217	* Merge two hash tables into one new hash table. If the same key
218	* is present in both tables, call the supplied merge function to
219	* produce a merged value for the key in the new table. Both
220	* hash tables must use the same hash function.
221	* @param p The pool to use for the new hash table
222	* @param h1 The first of the tables to merge
223	* @param h2 The second of the tables to merge
224	* @param merger A callback function to merge values, or NULL to
225	* make values from h1 override values from h2 (same semantics as
226	* apr_hash_overlay())
227	* @param data Client data to pass to the merger function
228	* @return A new hash table containing all of the data from the two passed in
229	*/
230	APR_DECLARE(apr_hash_t ) apr_hash_merge(apr_pool_t p,
231	const apr_hash_t *h1,
232	const apr_hash_t *h2,
233	void * (merger)(apr_pool_t p,
234	const void *key,
235	apr_ssize_t klen,
236	const void *h1_val,
237	const void *h2_val,
238	const void *data),
239	const void *data);
240
241	/**
242	* Declaration prototype for the iterator callback function of apr_hash_do().
243	*
244	* @param rec The data passed as the first argument to apr_hash_[v]do()
245	* @param key The key from this iteration of the hash table
246	* @param klen The key length from this iteration of the hash table
247	* @param value The value from this iteration of the hash table
248	* @remark Iteration continues while this callback function returns non-zero.
249	* To export the callback function for apr_hash_do() it must be declared
250	* in the _NONSTD convention.
251	*/
252	typedef int (apr_hash_do_callback_fn_t)(void rec, const void key,
253	apr_ssize_t klen,
254	const void *value);
255
256	/**
257	* Iterate over a hash table running the provided function once for every
258	* element in the hash table. The @param comp function will be invoked for
259	* every element in the hash table.
260	*
261	* @param comp The function to run
262	* @param rec The data to pass as the first argument to the function
263	* @param ht The hash table to iterate over
264	* @return FALSE if one of the comp() iterations returned zero; TRUE if all
265	* iterations returned non-zero
266	* @see apr_hash_do_callback_fn_t
267	*/
268	APR_DECLARE(int) apr_hash_do(apr_hash_do_callback_fn_t *comp,
269	void rec, const apr_hash_t ht);
270
271	/**
272	* Get a pointer to the pool which the hash table was created in
273	*/
274	APR_POOL_DECLARE_ACCESSOR(hash);
275
276	/** @} */
277
278	#ifdef __cplusplus
279	}
280	#endif
281
282	#endif /* !APR_HASH_H */