177 lines
6.0 KiB
C
177 lines
6.0 KiB
C
/* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership.
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* The ASF licenses this file to You under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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/*
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* sdbm - ndbm work-alike hashed database library
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* based on Per-Ake Larson's Dynamic Hashing algorithms. BIT 18 (1978).
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* author: oz@nexus.yorku.ca
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* status: ex-public domain
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*/
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#ifndef APR_SDBM_H
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#define APR_SDBM_H
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#include "apu.h"
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#include "apr_errno.h"
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#include "apr_file_io.h" /* for apr_fileperms_t */
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/**
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* @file apr_sdbm.h
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* @brief apr-util SDBM library
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*/
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/**
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* @defgroup APR_Util_DBM_SDBM SDBM library
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* @ingroup APR_Util_DBM
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* @{
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*/
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/**
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* Structure for referencing an sdbm
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*/
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typedef struct apr_sdbm_t apr_sdbm_t;
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/**
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* Structure for referencing the datum record within an sdbm
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*/
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typedef struct {
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/** pointer to the data stored/retrieved */
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char *dptr;
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/** size of data */
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/* apr_ssize_t for release 2.0??? */
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int dsize;
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} apr_sdbm_datum_t;
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/* The extensions used for the database files */
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/** SDBM Directory file extension */
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#define APR_SDBM_DIRFEXT ".dir"
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/** SDBM page file extension */
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#define APR_SDBM_PAGFEXT ".pag"
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/* flags to sdbm_store */
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#define APR_SDBM_INSERT 0 /**< Insert */
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#define APR_SDBM_REPLACE 1 /**< Replace */
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#define APR_SDBM_INSERTDUP 2 /**< Insert with duplicates */
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/**
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* Open an sdbm database by file name
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* @param db The newly opened database
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* @param name The sdbm file to open
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* @param mode The flag values (APR_READ and APR_BINARY flags are implicit)
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* <PRE>
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* APR_WRITE open for read-write access
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* APR_CREATE create the sdbm if it does not exist
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* APR_TRUNCATE empty the contents of the sdbm
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* APR_EXCL fail for APR_CREATE if the file exists
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* APR_DELONCLOSE delete the sdbm when closed
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* APR_SHARELOCK support locking across process/machines
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* </PRE>
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* @param perms Permissions to apply to if created
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* @param p The pool to use when creating the sdbm
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* @remark The sdbm name is not a true file name, as sdbm appends suffixes
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* for seperate data and index files.
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_open(apr_sdbm_t **db, const char *name,
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apr_int32_t mode,
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apr_fileperms_t perms, apr_pool_t *p);
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/**
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* Close an sdbm file previously opened by apr_sdbm_open
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* @param db The database to close
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_close(apr_sdbm_t *db);
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/**
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* Lock an sdbm database for concurency of multiple operations
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* @param db The database to lock
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* @param type The lock type
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* <PRE>
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* APR_FLOCK_SHARED
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* APR_FLOCK_EXCLUSIVE
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* </PRE>
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* @remark Calls to apr_sdbm_lock may be nested. All apr_sdbm functions
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* perform implicit locking. Since an APR_FLOCK_SHARED lock cannot be
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* portably promoted to an APR_FLOCK_EXCLUSIVE lock, apr_sdbm_store and
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* apr_sdbm_delete calls will fail if an APR_FLOCK_SHARED lock is held.
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* The apr_sdbm_lock call requires the database to be opened with the
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* APR_SHARELOCK mode value.
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_lock(apr_sdbm_t *db, int type);
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/**
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* Release an sdbm lock previously aquired by apr_sdbm_lock
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* @param db The database to unlock
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_unlock(apr_sdbm_t *db);
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/**
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* Fetch an sdbm record value by key
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* @param db The database
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* @param value The value datum retrieved for this record
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* @param key The key datum to find this record
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_fetch(apr_sdbm_t *db,
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apr_sdbm_datum_t *value,
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apr_sdbm_datum_t key);
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/**
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* Store an sdbm record value by key
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* @param db The database
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* @param key The key datum to store this record by
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* @param value The value datum to store in this record
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* @param opt The method used to store the record
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* <PRE>
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* APR_SDBM_INSERT return an error if the record exists
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* APR_SDBM_REPLACE overwrite any existing record for key
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* </PRE>
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_store(apr_sdbm_t *db, apr_sdbm_datum_t key,
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apr_sdbm_datum_t value, int opt);
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/**
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* Delete an sdbm record value by key
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* @param db The database
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* @param key The key datum of the record to delete
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* @remark It is not an error to delete a non-existent record.
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_delete(apr_sdbm_t *db,
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const apr_sdbm_datum_t key);
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/**
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* Retrieve the first record key from a dbm
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* @param db The database
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* @param key The key datum of the first record
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* @remark The keys returned are not ordered. To traverse the list of keys
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* for an sdbm opened with APR_SHARELOCK, the caller must use apr_sdbm_lock
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* prior to retrieving the first record, and hold the lock until after the
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* last call to apr_sdbm_nextkey.
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_firstkey(apr_sdbm_t *db, apr_sdbm_datum_t *key);
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/**
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* Retrieve the next record key from an sdbm
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* @param db The database
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* @param key The key datum of the next record
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*/
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APU_DECLARE(apr_status_t) apr_sdbm_nextkey(apr_sdbm_t *db, apr_sdbm_datum_t *key);
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/**
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* Returns true if the sdbm database opened for read-only access
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* @param db The database to test
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*/
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APU_DECLARE(int) apr_sdbm_rdonly(apr_sdbm_t *db);
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/** @} */
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#endif /* APR_SDBM_H */
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