Record Iteration Group

The Record Iteration Group contains the API for iterating over records in an MDBM. More...

Classes
struct	mdbm_page_info
struct	mdbm_entry_info
struct	mdbm_iterate_info

Macros
#define	MDBM_ENTRY_DELETED   0x1
#define	MDBM_ENTRY_LARGE_OBJECT   0x2
#define	MDBM_ITERATE_ENTRIES   0x01
	Iterate over page entries. More...
#define	MDBM_ITERATE_NOLOCK   0x80
	Iterate without locking. More...

Typedefs
typedef struct mdbm_page_info	mdbm_page_info_t
typedef struct mdbm_entry_info	mdbm_entry_info_t
typedef struct mdbm_iterate_info	mdbm_iterate_info_t
typedef int(*	mdbm_iterate_func_t )(void *user, const mdbm_iterate_info_t *info, const kvpair *kv)

Functions
kvpair	mdbm_first (MDBM *db)
	Returns the first key/value pair from the database. More...
kvpair	mdbm_first_r (MDBM *db, MDBM_ITER *iter)
	Fetches the first record in an MDBM. More...
kvpair	mdbm_next (MDBM *db)
	Returns the next key/value pair from the database. More...
kvpair	mdbm_next_r (MDBM *db, MDBM_ITER *iter)
	Fetches the next record in an MDBM. More...
datum	mdbm_firstkey (MDBM *db)
	Returns the first key from the database. More...
datum	mdbm_firstkey_r (MDBM *db, MDBM_ITER *iter)
	Fetches the first key in an MDBM. More...
datum	mdbm_nextkey (MDBM *db)
	Returns the next key pair from the database. More...
datum	mdbm_nextkey_r (MDBM *db, MDBM_ITER *iter)
	Fetches the next key in an MDBM. More...
int	mdbm_iterate (MDBM *db, int pagenum, mdbm_iterate_func_t func, int flags, void *user)
	Iterates through all keys starting on page pagenum and continuing through the rest of the database. More...

Detailed Description

The Record Iteration Group contains the API for iterating over records in an MDBM.

Macro Definition Documentation

#define MDBM_ENTRY_DELETED   0x1

#define MDBM_ENTRY_LARGE_OBJECT   0x2

#define MDBM_ITERATE_ENTRIES   0x01

Iterate over page entries.

#define MDBM_ITERATE_NOLOCK   0x80

Iterate without locking.

Typedef Documentation

typedef struct mdbm_page_info mdbm_page_info_t

typedef struct mdbm_entry_info mdbm_entry_info_t

typedef struct mdbm_iterate_info mdbm_iterate_info_t

typedef int(* mdbm_iterate_func_t)(void *user, const mdbm_iterate_info_t *info, const kvpair *kv)

Function Documentation

kvpair mdbm_first

(

MDBM *

db

)

Returns the first key/value pair from the database.

The order that records are returned is not specified.

Todo:

Is it safe to update/delete an entry returned via mdbm_first?

Parameters

[in,out]

db

Database handle

Returns

kvpair. If database is empty, return a null kvpair (key and value dsize==0, dptr==NULL).

kvpair mdbm_first_r	(	MDBM *	db,
		MDBM_ITER *	iter
	)

Fetches the first record in an MDBM.

Initializes the iterator, and returns the first key/value pair from the db. Subsequent calls to mdbm_next_r or mdbm_nextkey_r with this iterator will loop through the entire db.

Parameters

[in,out]	db	Database handle
[in,out]	iter	MDBM iterator

Returns

kvpair. If database is empty, return a null kvpair (key and value dsize==0, dptr==NULL).

kvpair mdbm_next

(

MDBM *

db

)

Returns the next key/value pair from the database.

The order that records are returned is not specified.

Todo:

Is it safe to update/delete an entry returned via mdbm_next?

Parameters

[in,out]

db

Database handle

Returns

kvpair. If no more records exist, return a null kvpair (key and value dsize==0, dptr==NULL).

kvpair mdbm_next_r	(	MDBM *	db,
		MDBM_ITER *	iter
	)

Fetches the next record in an MDBM.

Returns the next key/value pair from the db, based on the iterator.

Parameters

[in,out]	db	Database handle
[in,out]	iter	MDBM iterator

Returns

kvpair. If no more records exist, return a null kvpair (key and value dsize==0, dptr==NULL).

datum mdbm_firstkey

(

MDBM *

db

)

Returns the first key from the database.

The order that records are returned is not specified.

Parameters

[in,out]

db

Database handle

Returns

datum. If the database is empty, return a null datum (dsize==0, dptr==NULL).

datum mdbm_firstkey_r	(	MDBM *	db,
		MDBM_ITER *	iter
	)

Fetches the first key in an MDBM.

Initializes the iterator, and returns the first key from the db. Subsequent calls to mdbm_next_r or mdbm_nextkey_r with this iterator will loop through the entire db.

Parameters

[in,out]	db	Database handle
[in,out]	iter	MDBM iterator

Returns

datum. If the database is empty, return a null datum (dsize==0, dptr==NULL).

datum mdbm_nextkey

(

MDBM *

db

)

Returns the next key pair from the database.

The order that records are returned is not specified.

Parameters

[in,out]

db

Database handle

Returns

datum. If the database is empty, return a null datum (dsize==0, dptr==NULL).

datum mdbm_nextkey_r	(	MDBM *	db,
		MDBM_ITER *	iter
	)

Fetches the next key in an MDBM.

Returns the next key from the db. Subsequent calls to mdbm_next_r or mdbm_nextkey_r with this iterator will loop through the entire db.

Parameters

[in,out]	db	Database handle
[in,out]	iter	MDBM iterator

Returns

datum. If there are no more records, return a null datum (dsize==0, dptr==NULL).

int mdbm_iterate	(	MDBM *	db,
		int	pagenum,
		mdbm_iterate_func_t	func,
		int	flags,
		void *	user
	)

Iterates through all keys starting on page pagenum and continuing through the rest of the database.

If flags contains MDBM_ITERATE_ENTRIES, function func is invoked for each record. If flag does not have MDBM_ITERATE_ENTRIES set, then func is invoke once per page with kv set to NULL.

Parameters

[in,out]	db	Database handle
[in]	pagenum	Starting page number
[in]	func	Function to invoke for each key
[in]	flags	iteration control (below)
[in]	user	User-supplied opaque pointer to pass to func

Returns

Iteration status

Return values

-1	Error
0	Success

Values for flags mask:

• MDBM_ITERATE_NOLOCK - Do not lock when iterating
• MDBM_ITERATE_ENTRIES - Invoke func for each record