lcn_segments.h

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/* Copyright 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.
 */

/**
 * @file lcn_segments.h
 * @brief Routines for reading the segments contained within a lucen index
 */

#ifndef _LCN_SEGMENTS_H
#define _LCN_SEGMENTS_H

#include "lcn_types.h"
#include "lcn_directory.h"
#include "lcn_term.h"
#include "lcn_document.h"

#include <apr_pools.h>
#include <apr_tables.h>

#ifdef __cplusplus
extern "C" {
#endif /* __cplusplus */

/** Opaque structure representing the segments within an index. */
typedef struct lcn_segments_t lcn_segments_t;

/** Read in the segments file contained in @a directory and return it in
 * @a segments, allocated within @a pool.
 */
lcn_error_t *
lcn_segments_read (lcn_segments_t **segments,
                   const lcn_directory_t *directory,
                   apr_pool_t *pool);

/** Return the version of @a segments.
 *
 * This can be used to detect if the segment has been modified.
 */
apr_uint64_t lcn_segments_version (const lcn_segments_t *segments);

/** Return the number of segments within @a segments. */
unsigned int lcn_segments_count (const lcn_segments_t *segments);

/** Return the size (in documents) of segment @a name within @a segments. */
apr_uint32_t lcn_segments_segsize (const lcn_segments_t *segments,
                                   const lcn_char_t *name);

/** Return the names of the segments within @a segments, allocated in @a pool.
 *
 * The array holds @c lcn_char_t pointers.
 */
apr_array_header_t *
lcn_segments_names (const lcn_segments_t *segments, apr_pool_t *pool);

/** Return the max docs contained within @a segments. */
apr_uint32_t
lcn_segments_max_docs (const lcn_segments_t *segments);

/** Return the document freqency @a doc_freq, document numbers @a docs, and
 * frequencies @a freqs of the documents containing @a term in segment number
 * @a segnum within @a segments, using @a pool for allocation.
 */
lcn_error_t *
lcn_segments_term_docs (apr_uint32_t *doc_freq,
                        apr_uint32_t **docs,
                        apr_uint32_t **freqs,
                        lcn_segments_t *segments,
                        apr_uint32_t segnum,
                        const lcn_term_t *term,
                        apr_pool_t *pool);

/** Return the document @a docnum from @a segs in @a doc, using @a pool for
 * allocation.
 */
lcn_error_t *
lcn_segments_get_document (lcn_document_t **doc,
                           lcn_segments_t *segs,
                           apr_uint32_t docnum,
                           apr_pool_t *pool);

#ifdef __cplusplus
}
#endif /* __cplusplus */

#endif

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