midl.h

Go to the documentation of this file.

Go to the SVN repository for this file.

/** @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.
 */
/* $OpenLDAP$ */
/* This work is part of OpenLDAP Software <http://www.openldap.org/>.
 *
 * Copyright 2000-2019 The OpenLDAP Foundation.
 * Portions Copyright 2001-2018 Howard Chu, Symas Corp.
 * 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] )
 
    /** 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.
     */
unsigned mdb_midl_search( MDB_IDL ids, MDB_ID id );
 
    /** Allocate an IDL.
     * Allocates memory for an IDL of the given size.
     * @return  IDL on success, NULL on failure.
     */
MDB_IDL mdb_midl_alloc(int num);
 
    /** Free an IDL.
     * @param[in] ids   The IDL to free.
     */
void mdb_midl_free(MDB_IDL ids);
 
    /** 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.
     */
void mdb_midl_shrink(MDB_IDL *idp);
 
    /** 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.
     */
int mdb_midl_need(MDB_IDL *idp, unsigned num);
 
    /** 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.
     */
int mdb_midl_append( MDB_IDL *idp, MDB_ID id );
 
    /** 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.
     */
int mdb_midl_append_list( MDB_IDL *idp, MDB_IDL app );
 
    /** 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.
     */
int mdb_midl_append_range( MDB_IDL *idp, MDB_ID id, unsigned n );
 
    /** 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.
     */
void mdb_midl_xmerge( MDB_IDL idl, MDB_IDL merge );
 
    /** Sort an IDL.
     * @param[in,out] ids   The IDL to sort.
     */
void mdb_midl_sort( MDB_IDL ids );
 
    /** 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.
     */
unsigned mdb_mid2l_search( MDB_ID2L ids, MDB_ID id );
 
 
    /** 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.
     */
int mdb_mid2l_insert( MDB_ID2L ids, MDB_ID2 *id );
 
    /** 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.
     */
int mdb_mid2l_append( MDB_ID2L ids, MDB_ID2 *id );
 
/** @} */
/** @} */
#ifdef __cplusplus
}
#endif
#endif  /* _MDB_MIDL_H_ */