libmdbx/midl.h

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/** @file midl.h
* @brief LMDB ID List header file.
*
* This file was originally part of back-bdb but has been
* modified for use in libmdb. Most of the macros defined
* in this file are unused, just left over from the original.
*
* This file is only used internally in libmdb and its definitions
* are not exposed publicly.
*/
/*
* Copyright (c) 2015,2016 Leonid Yuriev <leo@yuriev.ru>.
* Copyright (c) 2015,2016 Peter-Service R&D LLC.
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*
* This file is part of ReOpenMDBX.
*
* ReOpenMDBX is free software; you can redistribute it and/or modify it under
* the terms of the GNU Affero General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* ReOpenMDBX 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* ---
*
* Copyright 2000-2016 The OpenLDAP Foundation.
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* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted only as authorized by the OpenLDAP
* Public License.
*
* A copy of this license is available in the file LICENSE in the
* top-level directory of the distribution or, alternatively, at
* <http://www.OpenLDAP.org/license.html>.
*/
#ifndef _MDB_MIDL_H_
#define _MDB_MIDL_H_
#include <stddef.h>
#ifdef __cplusplus
extern "C" {
#endif
/** @defgroup internal LMDB Internals
* @{
*/
/** @defgroup idls ID List Management
* @{
*/
/** A generic unsigned ID number. These were entryIDs in back-bdb.
* Preferably it should have the same size as a pointer.
*/
typedef size_t MDB_ID;
/** An IDL is an ID List, a sorted array of IDs. The first
* element of the array is a counter for how many actual
* IDs are in the list. In the original back-bdb code, IDLs are
* sorted in ascending order. For libmdb IDLs are sorted in
* descending order.
*/
typedef MDB_ID *MDB_IDL;
/* IDL sizes - likely should be even bigger
* limiting factors: sizeof(ID), thread stack size
*/
#define MDB_IDL_LOGN 16 /* DB_SIZE is 2^16, UM_SIZE is 2^17 */
#define MDB_IDL_DB_SIZE (1<<MDB_IDL_LOGN)
#define MDB_IDL_UM_SIZE (1<<(MDB_IDL_LOGN+1))
#define MDB_IDL_DB_MAX (MDB_IDL_DB_SIZE-1)
#define MDB_IDL_UM_MAX (MDB_IDL_UM_SIZE-1)
#define MDB_IDL_SIZEOF(ids) (((ids)[0]+1) * sizeof(MDB_ID))
#define MDB_IDL_IS_ZERO(ids) ( (ids)[0] == 0 )
#define MDB_IDL_CPY( dst, src ) (memcpy( dst, src, MDB_IDL_SIZEOF( src ) ))
#define MDB_IDL_FIRST( ids ) ( (ids)[1] )
#define MDB_IDL_LAST( ids ) ( (ids)[(ids)[0]] )
/** Current max length of an #mdb_midl_alloc()ed IDL */
#define MDB_IDL_ALLOCLEN( ids ) ( (ids)[-1] )
#ifdef MDBX_MODE_ENABLED
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/** Append ID to IDL. The IDL must be big enough. */
#define mdb_midl_xappend(idl, id) do { \
MDB_ID *xidl = (idl), xlen = ++(xidl[0]); \
xidl[xlen] = (id); \
} while (0)
/** Search for an ID in an IDL.
* @param[in] ids The IDL to search.
* @param[in] id The ID to search for.
* @return The index of the first ID greater than or equal to \b id.
*/
static unsigned mdb_midl_search( MDB_IDL ids, MDB_ID id );
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/** Allocate an IDL.
* Allocates memory for an IDL of the given size.
* @return IDL on success, NULL on failure.
*/
static MDB_IDL mdb_midl_alloc(int num);
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/** Free an IDL.
* @param[in] ids The IDL to free.
*/
static void mdb_midl_free(MDB_IDL ids);
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/** Shrink an IDL.
* Return the IDL to the default size if it has grown larger.
* @param[in,out] idp Address of the IDL to shrink.
*/
static void mdb_midl_shrink(MDB_IDL *idp);
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/** Make room for num additional elements in an IDL.
* @param[in,out] idp Address of the IDL.
* @param[in] num Number of elements to make room for.
* @return 0 on success, ENOMEM on failure.
*/
static int mdb_midl_need(MDB_IDL *idp, unsigned num);
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/** Append an ID onto an IDL.
* @param[in,out] idp Address of the IDL to append to.
* @param[in] id The ID to append.
* @return 0 on success, ENOMEM if the IDL is too large.
*/
static int mdb_midl_append( MDB_IDL *idp, MDB_ID id );
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/** Append an IDL onto an IDL.
* @param[in,out] idp Address of the IDL to append to.
* @param[in] app The IDL to append.
* @return 0 on success, ENOMEM if the IDL is too large.
*/
static int mdb_midl_append_list( MDB_IDL *idp, MDB_IDL app );
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/** Append an ID range onto an IDL.
* @param[in,out] idp Address of the IDL to append to.
* @param[in] id The lowest ID to append.
* @param[in] n Number of IDs to append.
* @return 0 on success, ENOMEM if the IDL is too large.
*/
static int mdb_midl_append_range( MDB_IDL *idp, MDB_ID id, unsigned n );
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/** Merge an IDL onto an IDL. The destination IDL must be big enough.
* @param[in] idl The IDL to merge into.
* @param[in] merge The IDL to merge.
*/
static void mdb_midl_xmerge( MDB_IDL idl, MDB_IDL merge );
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/** Sort an IDL.
* @param[in,out] ids The IDL to sort.
*/
static void mdb_midl_sort( MDB_IDL ids );
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/** An ID2 is an ID/pointer pair.
*/
typedef struct MDB_ID2 {
MDB_ID mid; /**< The ID */
void *mptr; /**< The pointer */
} MDB_ID2;
/** An ID2L is an ID2 List, a sorted array of ID2s.
* The first element's \b mid member is a count of how many actual
* elements are in the array. The \b mptr member of the first element is unused.
* The array is sorted in ascending order by \b mid.
*/
typedef MDB_ID2 *MDB_ID2L;
/** Search for an ID in an ID2L.
* @param[in] ids The ID2L to search.
* @param[in] id The ID to search for.
* @return The index of the first ID2 whose \b mid member is greater than or equal to \b id.
*/
static unsigned mdb_mid2l_search( MDB_ID2L ids, MDB_ID id );
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/** Insert an ID2 into a ID2L.
* @param[in,out] ids The ID2L to insert into.
* @param[in] id The ID2 to insert.
* @return 0 on success, -1 if the ID was already present in the ID2L.
*/
static int mdb_mid2l_insert( MDB_ID2L ids, MDB_ID2 *id );
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/** Append an ID2 into a ID2L.
* @param[in,out] ids The ID2L to append into.
* @param[in] id The ID2 to append.
* @return 0 on success, -2 if the ID2L is too big.
*/
static int mdb_mid2l_append( MDB_ID2L ids, MDB_ID2 *id );
#endif /* #ifdef MDBX_MODE_ENABLED */
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/** @} */
/** @} */
#ifdef __cplusplus
}
#endif
#endif /* _MDB_MIDL_H_ */