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| -rw-r--r-- | include/apr_sdbm.h | 176 |
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diff --git a/include/apr_sdbm.h b/include/apr_sdbm.h new file mode 100644 index 0000000..5759508 --- /dev/null +++ b/include/apr_sdbm.h @@ -0,0 +1,176 @@ +/* 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. + */ + +/* + * sdbm - ndbm work-alike hashed database library + * based on Per-Ake Larson's Dynamic Hashing algorithms. BIT 18 (1978). + * author: oz@nexus.yorku.ca + * status: ex-public domain + */ + +#ifndef APR_SDBM_H +#define APR_SDBM_H + +#include "apu.h" +#include "apr_errno.h" +#include "apr_file_io.h" /* for apr_fileperms_t */ + +/** + * @file apr_sdbm.h + * @brief apr-util SDBM library + */ +/** + * @defgroup APR_Util_DBM_SDBM SDBM library + * @ingroup APR_Util_DBM + * @{ + */ + +/** + * Structure for referencing an sdbm + */ +typedef struct apr_sdbm_t apr_sdbm_t; + +/** + * Structure for referencing the datum record within an sdbm + */ +typedef struct { + /** pointer to the data stored/retrieved */ + char *dptr; + /** size of data */ + /* apr_ssize_t for release 2.0??? */ + int dsize; +} apr_sdbm_datum_t; + +/* The extensions used for the database files */ +/** SDBM Directory file extension */ +#define APR_SDBM_DIRFEXT ".dir" +/** SDBM page file extension */ +#define APR_SDBM_PAGFEXT ".pag" + +/* flags to sdbm_store */ +#define APR_SDBM_INSERT 0 /**< Insert */ +#define APR_SDBM_REPLACE 1 /**< Replace */ +#define APR_SDBM_INSERTDUP 2 /**< Insert with duplicates */ + +/** + * Open an sdbm database by file name + * @param db The newly opened database + * @param name The sdbm file to open + * @param mode The flag values (APR_READ and APR_BINARY flags are implicit) + * <PRE> + * APR_WRITE open for read-write access + * APR_CREATE create the sdbm if it does not exist + * APR_TRUNCATE empty the contents of the sdbm + * APR_EXCL fail for APR_CREATE if the file exists + * APR_DELONCLOSE delete the sdbm when closed + * APR_SHARELOCK support locking across process/machines + * </PRE> + * @param perms Permissions to apply to if created + * @param p The pool to use when creating the sdbm + * @remark The sdbm name is not a true file name, as sdbm appends suffixes + * for seperate data and index files. + */ +APU_DECLARE(apr_status_t) apr_sdbm_open(apr_sdbm_t **db, const char *name, + apr_int32_t mode, + apr_fileperms_t perms, apr_pool_t *p); + +/** + * Close an sdbm file previously opened by apr_sdbm_open + * @param db The database to close + */ +APU_DECLARE(apr_status_t) apr_sdbm_close(apr_sdbm_t *db); + +/** + * Lock an sdbm database for concurency of multiple operations + * @param db The database to lock + * @param type The lock type + * <PRE> + * APR_FLOCK_SHARED + * APR_FLOCK_EXCLUSIVE + * </PRE> + * @remark Calls to apr_sdbm_lock may be nested. All apr_sdbm functions + * perform implicit locking. Since an APR_FLOCK_SHARED lock cannot be + * portably promoted to an APR_FLOCK_EXCLUSIVE lock, apr_sdbm_store and + * apr_sdbm_delete calls will fail if an APR_FLOCK_SHARED lock is held. + * The apr_sdbm_lock call requires the database to be opened with the + * APR_SHARELOCK mode value. + */ +APU_DECLARE(apr_status_t) apr_sdbm_lock(apr_sdbm_t *db, int type); + +/** + * Release an sdbm lock previously aquired by apr_sdbm_lock + * @param db The database to unlock + */ +APU_DECLARE(apr_status_t) apr_sdbm_unlock(apr_sdbm_t *db); + +/** + * Fetch an sdbm record value by key + * @param db The database + * @param value The value datum retrieved for this record + * @param key The key datum to find this record + */ +APU_DECLARE(apr_status_t) apr_sdbm_fetch(apr_sdbm_t *db, + apr_sdbm_datum_t *value, + apr_sdbm_datum_t key); + +/** + * Store an sdbm record value by key + * @param db The database + * @param key The key datum to store this record by + * @param value The value datum to store in this record + * @param opt The method used to store the record + * <PRE> + * APR_SDBM_INSERT return an error if the record exists + * APR_SDBM_REPLACE overwrite any existing record for key + * </PRE> + */ +APU_DECLARE(apr_status_t) apr_sdbm_store(apr_sdbm_t *db, apr_sdbm_datum_t key, + apr_sdbm_datum_t value, int opt); + +/** + * Delete an sdbm record value by key + * @param db The database + * @param key The key datum of the record to delete + * @remark It is not an error to delete a non-existent record. + */ +APU_DECLARE(apr_status_t) apr_sdbm_delete(apr_sdbm_t *db, + const apr_sdbm_datum_t key); + +/** + * Retrieve the first record key from a dbm + * @param db The database + * @param key The key datum of the first record + * @remark The keys returned are not ordered. To traverse the list of keys + * for an sdbm opened with APR_SHARELOCK, the caller must use apr_sdbm_lock + * prior to retrieving the first record, and hold the lock until after the + * last call to apr_sdbm_nextkey. + */ +APU_DECLARE(apr_status_t) apr_sdbm_firstkey(apr_sdbm_t *db, apr_sdbm_datum_t *key); + +/** + * Retrieve the next record key from an sdbm + * @param db The database + * @param key The key datum of the next record + */ +APU_DECLARE(apr_status_t) apr_sdbm_nextkey(apr_sdbm_t *db, apr_sdbm_datum_t *key); + +/** + * Returns true if the sdbm database opened for read-only access + * @param db The database to test + */ +APU_DECLARE(int) apr_sdbm_rdonly(apr_sdbm_t *db); +/** @} */ +#endif /* APR_SDBM_H */ |