| /* $Id$ */ |
| /* |
| * Copyright (C) 2008-2011 Teluu Inc. (http://www.teluu.com) |
| * Copyright (C) 2003-2008 Benny Prijono <benny@prijono.org> |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License as published by |
| * the Free Software Foundation; either version 2 of the License, or |
| * (at your option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA |
| */ |
| #ifndef __PJ_HASH_H__ |
| #define __PJ_HASH_H__ |
| |
| /** |
| * @file hash.h |
| * @brief Hash Table. |
| */ |
| |
| #include <pj/types.h> |
| |
| PJ_BEGIN_DECL |
| |
| /** |
| * @defgroup PJ_HASH Hash Table |
| * @ingroup PJ_DS |
| * @{ |
| * A hash table is a dictionary in which keys are mapped to array positions by |
| * hash functions. Having the keys of more than one item map to the same |
| * position is called a collision. In this library, we will chain the nodes |
| * that have the same key in a list. |
| */ |
| |
| /** |
| * If this constant is used as keylen, then the key is interpreted as |
| * NULL terminated string. |
| */ |
| #define PJ_HASH_KEY_STRING ((unsigned)-1) |
| |
| /** |
| * This indicates the size of of each hash entry. |
| */ |
| #define PJ_HASH_ENTRY_BUF_SIZE (3*sizeof(void*) + 2*sizeof(pj_uint32_t)) |
| |
| /** |
| * Type declaration for entry buffer, used by #pj_hash_set_np() |
| */ |
| typedef void *pj_hash_entry_buf[(PJ_HASH_ENTRY_BUF_SIZE+sizeof(void*)-1)/(sizeof(void*))]; |
| |
| /** |
| * This is the function that is used by the hash table to calculate hash value |
| * of the specified key. |
| * |
| * @param hval the initial hash value, or zero. |
| * @param key the key to calculate. |
| * @param keylen the length of the key, or PJ_HASH_KEY_STRING to treat |
| * the key as null terminated string. |
| * |
| * @return the hash value. |
| */ |
| PJ_DECL(pj_uint32_t) pj_hash_calc(pj_uint32_t hval, |
| const void *key, unsigned keylen); |
| |
| |
| /** |
| * Convert the key to lowercase and calculate the hash value. The resulting |
| * string is stored in \c result. |
| * |
| * @param hval The initial hash value, normally zero. |
| * @param result Optional. Buffer to store the result, which must be enough |
| * to hold the string. |
| * @param key The input key to be converted and calculated. |
| * |
| * @return The hash value. |
| */ |
| PJ_DECL(pj_uint32_t) pj_hash_calc_tolower(pj_uint32_t hval, |
| char *result, |
| const pj_str_t *key); |
| |
| /** |
| * Create a hash table with the specified 'bucket' size. |
| * |
| * @param pool the pool from which the hash table will be allocated from. |
| * @param size the bucket size, which will be round-up to the nearest 2^n-1 |
| * |
| * @return the hash table. |
| */ |
| PJ_DECL(pj_hash_table_t*) pj_hash_create(pj_pool_t *pool, unsigned size); |
| |
| |
| /** |
| * Get the value associated with the specified key. |
| * |
| * @param ht the hash table. |
| * @param key the key to look for. |
| * @param keylen the length of the key, or PJ_HASH_KEY_STRING to use the |
| * string length of the key. |
| * @param hval if this argument is not NULL and the value is not zero, |
| * the value will be used as the computed hash value. If |
| * the argument is not NULL and the value is zero, it will |
| * be filled with the computed hash upon return. |
| * |
| * @return the value associated with the key, or NULL if the key is not found. |
| */ |
| PJ_DECL(void *) pj_hash_get( pj_hash_table_t *ht, |
| const void *key, unsigned keylen, |
| pj_uint32_t *hval ); |
| |
| |
| /** |
| * Variant of #pj_hash_get() with the key being converted to lowercase when |
| * calculating the hash value. |
| * |
| * @see pj_hash_get() |
| */ |
| PJ_DECL(void *) pj_hash_get_lower( pj_hash_table_t *ht, |
| const void *key, unsigned keylen, |
| pj_uint32_t *hval ); |
| |
| |
| /** |
| * Associate/disassociate a value with the specified key. If value is not |
| * NULL and entry already exists, the entry's value will be overwritten. |
| * If value is not NULL and entry does not exist, a new one will be created |
| * with the specified pool. Otherwise if value is NULL, entry will be |
| * deleted if it exists. |
| * |
| * @param pool the pool to allocate the new entry if a new entry has to be |
| * created. |
| * @param ht the hash table. |
| * @param key the key. If pool is not specified, the key MUST point to |
| * buffer that remains valid for the duration of the entry. |
| * @param keylen the length of the key, or PJ_HASH_KEY_STRING to use the |
| * string length of the key. |
| * @param hval if the value is not zero, then the hash table will use |
| * this value to search the entry's index, otherwise it will |
| * compute the key. This value can be obtained when calling |
| * #pj_hash_get(). |
| * @param value value to be associated, or NULL to delete the entry with |
| * the specified key. |
| */ |
| PJ_DECL(void) pj_hash_set( pj_pool_t *pool, pj_hash_table_t *ht, |
| const void *key, unsigned keylen, pj_uint32_t hval, |
| void *value ); |
| |
| |
| /** |
| * Variant of #pj_hash_set() with the key being converted to lowercase when |
| * calculating the hash value. |
| * |
| * @see pj_hash_set() |
| */ |
| PJ_DECL(void) pj_hash_set_lower( pj_pool_t *pool, pj_hash_table_t *ht, |
| const void *key, unsigned keylen, |
| pj_uint32_t hval, void *value ); |
| |
| |
| /** |
| * Associate/disassociate a value with the specified key. This function works |
| * like #pj_hash_set(), except that it doesn't use pool (hence the np -- no |
| * pool suffix). If new entry needs to be allocated, it will use the entry_buf. |
| * |
| * @param ht the hash table. |
| * @param key the key. |
| * @param keylen the length of the key, or PJ_HASH_KEY_STRING to use the |
| * string length of the key. |
| * @param hval if the value is not zero, then the hash table will use |
| * this value to search the entry's index, otherwise it will |
| * compute the key. This value can be obtained when calling |
| * #pj_hash_get(). |
| * @param entry_buf Buffer which will be used for the new entry, when one needs |
| * to be created. |
| * @param value value to be associated, or NULL to delete the entry with |
| * the specified key. |
| */ |
| PJ_DECL(void) pj_hash_set_np(pj_hash_table_t *ht, |
| const void *key, unsigned keylen, |
| pj_uint32_t hval, pj_hash_entry_buf entry_buf, |
| void *value); |
| |
| /** |
| * Variant of #pj_hash_set_np() with the key being converted to lowercase |
| * when calculating the hash value. |
| * |
| * @see pj_hash_set_np() |
| */ |
| PJ_DECL(void) pj_hash_set_np_lower(pj_hash_table_t *ht, |
| const void *key, unsigned keylen, |
| pj_uint32_t hval, |
| pj_hash_entry_buf entry_buf, |
| void *value); |
| |
| /** |
| * Get the total number of entries in the hash table. |
| * |
| * @param ht the hash table. |
| * |
| * @return the number of entries in the hash table. |
| */ |
| PJ_DECL(unsigned) pj_hash_count( pj_hash_table_t *ht ); |
| |
| |
| /** |
| * Get the iterator to the first element in the hash table. |
| * |
| * @param ht the hash table. |
| * @param it the iterator for iterating hash elements. |
| * |
| * @return the iterator to the hash element, or NULL if no element presents. |
| */ |
| PJ_DECL(pj_hash_iterator_t*) pj_hash_first( pj_hash_table_t *ht, |
| pj_hash_iterator_t *it ); |
| |
| |
| /** |
| * Get the next element from the iterator. |
| * |
| * @param ht the hash table. |
| * @param it the hash iterator. |
| * |
| * @return the next iterator, or NULL if there's no more element. |
| */ |
| PJ_DECL(pj_hash_iterator_t*) pj_hash_next( pj_hash_table_t *ht, |
| pj_hash_iterator_t *it ); |
| |
| /** |
| * Get the value associated with a hash iterator. |
| * |
| * @param ht the hash table. |
| * @param it the hash iterator. |
| * |
| * @return the value associated with the current element in iterator. |
| */ |
| PJ_DECL(void*) pj_hash_this( pj_hash_table_t *ht, |
| pj_hash_iterator_t *it ); |
| |
| |
| /** |
| * @} |
| */ |
| |
| PJ_END_DECL |
| |
| #endif |
| |
| |