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/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
* applicable.
*
* Licensed 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 */
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 */
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