#include <sys/types.h>
+/** @defgroup public Public API
+ * @{
+ */
/** @defgroup Version Version Macros
* @{
*/
/** Library major version */
#define MDB_VERSION_MAJOR 0
/** Library minor version */
-#define MDB_VERSION_MINOR 8
+#define MDB_VERSION_MINOR 9
/** Library patch version */
#define MDB_VERSION_PATCH 0
MDB_VERINT(MDB_VERSION_MAJOR,MDB_VERSION_MINOR,MDB_VERSION_PATCH)
/** The release date of this library version */
-#define MDB_VERSION_DATE "August 11, 2011"
+#define MDB_VERSION_DATE "September 1, 2011"
/** A stringifier for the version info */
#define MDB_VERSTR(a,b,c,d) "MDB " #a "." #b "." #c ": (" #d ")"
MDB_VERFOO(MDB_VERSION_MAJOR,MDB_VERSION_MINOR,MDB_VERSION_PATCH,MDB_VERSION_DATE)
/** @} */
-/** Opaque structure for navigating through a database */
-typedef struct MDB_cursor MDB_cursor;
+/** Opaque structure for a database environment. A DB environment supports multiple
+ * databases, all residing in the same shared-memory map.
+ */
+typedef struct MDB_env MDB_env;
/** Opaque structure for a transaction handle. All database operations require
* a transaction handle. Transactions may be read-only or read-write.
*/
typedef struct MDB_txn MDB_txn;
-/** Opaque structure for a database environment. A DB environment supports multiple
- * databases, all residing in the same shared-memory map.
- */
-typedef struct MDB_env MDB_env;
-
/** A handle for an individual database in the DB environment. */
typedef unsigned int MDB_dbi;
+/** Opaque structure for navigating through a database */
+typedef struct MDB_cursor MDB_cursor;
+
/** Generic structure used for passing keys and data in and out of the database. */
typedef struct MDB_val {
size_t mv_size; /**< size of the data item */
typedef int (MDB_cmp_func)(const MDB_val *a, const MDB_val *b);
/** A callback function used to relocate a position-dependent data item
- * in a fixed-address database. This feature is currently unimplemented.
+ * in a fixed-address database. The \b newptr gives the item's desired address in
+ * the memory map, and \b oldptr gives its previous address. The item's actual
+ * data resides at the address in \b item. This callback is expected to walk
+ * through the fields of the record in \b item and modify any
+ * values based at the \b oldptr address to be relative to the \b newptr address.
+ * @param[in,out] item The item that is to be relocated.
+ * @param[in] oldptr The previous address.
+ * @param[in] newptr The new address to relocate to.
+ * @param[in] relctx An application-provided context, set by #mdb_set_relctx().
+ * @todo This feature is currently unimplemented.
*/
-typedef void (MDB_rel_func)(void *ptr, void *oldptr);
+typedef void (MDB_rel_func)(MDB_val *item, void *oldptr, void *newptr, void *relctx);
-/** @defgroup mdb_put mdb_put flags
+/** @defgroup mdb_env Environment Flags
* @{
*/
-/** For mdb_put: don't write if the key already exists. */
+ /** mmap at a fixed address */
+#define MDB_FIXEDMAP 0x01
+ /** don't fsync after commit */
+#define MDB_NOSYNC 0x10000
+ /** read only */
+#define MDB_RDONLY 0x20000
+/** @} */
+
+/** @defgroup mdb_open Database Flags
+ * @{
+ */
+ /** use reverse string keys */
+#define MDB_REVERSEKEY 0x02
+ /** use sorted duplicates */
+#define MDB_DUPSORT 0x04
+ /** numeric keys in native byte order.
+ * The keys must all be of the same size. */
+#define MDB_INTEGERKEY 0x08
+ /** with #MDB_DUPSORT, sorted dup items have fixed size */
+#define MDB_DUPFIXED 0x10
+ /** with #MDB_DUPSORT, dups are numeric in native byte order */
+#define MDB_INTEGERDUP 0x20
+ /** with #MDB_DUPSORT, use reverse string dups */
+#define MDB_REVERSEDUP 0x40
+ /** create DB if not already existing */
+#define MDB_CREATE 0x40000
+/** @} */
+
+/** @defgroup mdb_put Write Flags
+ * @{
+ */
+/** For put: Don't write if the key already exists. */
#define MDB_NOOVERWRITE 0x10
-/** For mdb_put: don't write if the key and data pair already exist.
- * Only for #MDB_DUPSORT
+/** Only for #MDB_DUPSORT<br>
+ * For put: don't write if the key and data pair already exist.<br>
+ * For mdb_cursor_del: remove all duplicate data items.
*/
#define MDB_NODUPDATA 0x20
+/** For mdb_cursor_put: overwrite the current key/data pair */
+#define MDB_CURRENT 0x40
/* @} */
-/** Cursor operations */
+/** Cursor Get operations
+ * This is the set of all operations for retrieving data
+ * using a cursor.
+ */
typedef enum MDB_cursor_op {
MDB_FIRST, /**< Position at first key/data item */
+ MDB_FIRST_DUP, /**< Position at first data item of current key.
+ Only for #MDB_DUPSORT */
MDB_GET_BOTH, /**< Position at key/data pair. Only for #MDB_DUPSORT */
MDB_GET_BOTH_RANGE, /**< position at key, nearest data. Only for #MDB_DUPSORT */
MDB_GET_MULTIPLE, /**< Return all the duplicate data items at the current
cursor position. Only for #MDB_DUPFIXED */
MDB_LAST, /**< Position at last key/data item */
+ MDB_LAST_DUP, /**< Position at last data item of current key.
+ Only for #MDB_DUPSORT */
MDB_NEXT, /**< Position at next data item */
MDB_NEXT_DUP, /**< Position at next data item of current key.
Only for #MDB_DUPSORT */
MDB_PREV_DUP, /**< Position at previous data item of current key.
Only for #MDB_DUPSORT */
MDB_PREV_NODUP, /**< Position at last data item of previous key.
- only for #MDB_DUPSORT */
+ Only for #MDB_DUPSORT */
MDB_SET, /**< Position at specified key */
MDB_SET_RANGE /**< Position at first key greater than or equal to specified key. */
} MDB_cursor_op;
#define MDB_VERSION_MISMATCH (-30794)
/** @} */
-/** @defgroup mdb_open mdb_open flags
- * @{
- */
- /** use reverse string keys */
-#define MDB_REVERSEKEY 0x02
- /** use sorted duplicates */
-#define MDB_DUPSORT 0x04
- /** numeric keys in native byte order */
-#define MDB_INTEGERKEY 0x08
- /** with #MDB_DUPSORT, sorted dup items have fixed size */
-#define MDB_DUPFIXED 0x10
- /** with #MDB_DUPSORT, dups are numeric in native byte order */
-#define MDB_INTEGERDUP 0x20
-/** @} */
-
-/** @defgroup mdb_env environment flags
- * @{
- */
- /** mmap at a fixed address */
-#define MDB_FIXEDMAP 0x01
- /** don't fsync after commit */
-#define MDB_NOSYNC 0x10000
- /** read only */
-#define MDB_RDONLY 0x20000
-/** @} */
-
- /** create env or DB if not already existing */
-#define MDB_CREATE 0x40000
-
/** Statistics for a database in the environment */
typedef struct MDB_stat {
unsigned int ms_psize; /**< Size of a database page.
This is currently the same for all databases. */
unsigned int ms_depth; /**< Depth (height) of the B-tree */
- unsigned long ms_branch_pages; /**< Number of internal (non-leaf) pages */
- unsigned long ms_leaf_pages; /**< Number of leaf pages */
- unsigned long ms_overflow_pages; /**< Number of overflow pages */
- unsigned long ms_entries; /**< Number of data items */
+ size_t ms_branch_pages; /**< Number of internal (non-leaf) pages */
+ size_t ms_leaf_pages; /**< Number of leaf pages */
+ size_t ms_overflow_pages; /**< Number of overflow pages */
+ size_t ms_entries; /**< Number of data items */
} MDB_stat;
/** Return the mdb library version information.
/** Open an environment handle.
* If this function fails, #mdb_env_close() must be called to discard the #MDB_env handle.
* @param[in] env An environment handle returned by #mdb_env_create()
- * @param[in] path The directory in which the database files reside
+ * @param[in] path The directory in which the database files reside. This
+ * directory must already exist and be writable.
* @param[in] flags Special options for this environment. This parameter
* must be set to 0 or by bitwise OR'ing together one or more of the
* values described here.
* at any time using #mdb_env_set_flags().
* <li>#MDB_RDONLY
* Open the environment in read-only mode. No write operations will be allowed.
- * <li>#MDB_CREATE
- * Create the environment if it doesn't already exist.
* </ul>
- * @param[in] mode The UNIX permissions to set on created files.
+ * @param[in] mode The UNIX permissions to set on created files. This parameter
+ * is ignored on Windows.
* @return A non-zero error value on failure and 0 on success. Some possible
* errors are:
* <ul>
/** Set the size of the memory map to use for this environment.
* The size should be a multiple of the OS page size. The default is
- * 10485760 bytes. The value should be chosen as large as possible,
+ * 10485760 bytes. The size of the memory map is also the maximum size
+ * of the database. The value should be chosen as large as possible,
* to accomodate future growth of the database.
* This function may only be called after #mdb_env_create() and before #mdb_env_open().
* @param[in] env An environment handle returned by #mdb_env_create()
* <li>EINVAL - an invalid parameter was specified, or the environment is already open.
* </ul>
*/
-int mdb_env_set_maxreaders(MDB_env *env, int readers);
+int mdb_env_set_maxreaders(MDB_env *env, unsigned int readers);
/** Get the maximum number of threads for the environment.
* @param[in] env An environment handle returned by #mdb_env_create()
* <li>EINVAL - an invalid parameter was specified.
* </ul>
*/
-int mdb_env_get_maxreaders(MDB_env *env, int *readers);
+int mdb_env_get_maxreaders(MDB_env *env, unsigned int *readers);
/** Set the maximum number of databases for the environment.
* This function is only needed if multiple databases will be used in the
* <li>EINVAL - an invalid parameter was specified, or the environment is already open.
* </ul>
*/
-int mdb_env_set_maxdbs(MDB_env *env, int dbs);
+int mdb_env_set_maxdbs(MDB_env *env, MDB_dbi dbs);
/** Create a transaction for use with the environment.
* The transaction handle may be discarded using #mdb_txn_abort() or #mdb_txn_commit().
/** Reset a read-only transaction.
* This releases the current reader lock but doesn't free the
* transaction handle, allowing it to be used again later by #mdb_txn_renew().
- * It otherwise has the same affect as #mdb_txn_abort() but saves some memory
+ * It otherwise has the same effect as #mdb_txn_abort() but saves some memory
* allocation/deallocation overhead if a thread is going to start a new
* read-only transaction again soon.
* All cursors opened within the transaction must be closed before the transaction
* keys may have multiple data items, stored in sorted order.) By default
* keys must be unique and may have only a single data item.
* <li>#MDB_INTEGERKEY
- * Keys are binary integers in native byte order. On Big-Endian systems
- * this flag has no effect. On Little-Endian systems this flag behaves
- * the same as #MDB_REVERSEKEY. This flag is simply provided as a
- * convenience so that applications don't need to detect Endianness themselves
- * when using integers as keys.
+ * Keys are binary integers in native byte order. Setting this option
+ * requires all keys to be the same size, typically sizeof(int)
+ * or sizeof(size_t).
* <li>#MDB_DUPFIXED
* This flag may only be used in combination with #MDB_DUPSORT. This option
* tells the library that the data items for this database are all the same
* <li>#MDB_INTEGERDUP
* This option specifies that duplicate data items are also integers, and
* should be sorted as such.
+ * <li>#MDB_REVERSEDUP
+ * This option specifies that duplicate data items should be compared as
+ * strings in reverse order.
* <li>#MDB_CREATE
* Create the named database if it doesn't exist. This option is not
* allowed in a read-only transaction or a read-only environment.
* with #mdb_open(), the keys are compared lexically, with shorter keys collating
* before longer keys.
* @warning This function must be called before any data access functions are used,
- * otherwise data corruption may occur. The same function must be used by every
- * process accessing the database, every time the database is used.
+ * otherwise data corruption may occur. The same comparison function must be used by every
+ * program accessing the database, every time the database is used.
* @param[in] txn A transaction handle returned by #mdb_txn_begin()
* @param[in] dbi A database handle returned by #mdb_open()
* @param[in] cmp A #MDB_cmp_func function
* with #mdb_open(), the data items are compared lexically, with shorter items collating
* before longer items.
* @warning This function must be called before any data access functions are used,
- * otherwise data corruption may occur. The same function must be used by every
- * process accessing the database, every time the database is used.
+ * otherwise data corruption may occur. The same comparison function must be used by every
+ * program accessing the database, every time the database is used.
* @param[in] txn A transaction handle returned by #mdb_txn_begin()
* @param[in] dbi A database handle returned by #mdb_open()
* @param[in] cmp A #MDB_cmp_func function
*/
int mdb_set_relfunc(MDB_txn *txn, MDB_dbi dbi, MDB_rel_func *rel);
+ /** Set a context pointer for a #MDB_FIXEDMAP database's relocation function.
+ * See #mdb_set_relfunc and #MDB_rel_func for more details.
+ * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+ * @param[in] dbi A database handle returned by #mdb_open()
+ * @param[in] ctx An arbitrary pointer for whatever the application needs.
+ * It will be passed to the callback function set by #mdb_set_relfunc
+ * as its \b relctx parameter whenever the callback is invoked.
+ * @return A non-zero error value on failure and 0 on success. Some possible
+ * errors are:
+ * <ul>
+ * <li>EINVAL - an invalid parameter was specified.
+ * </ul>
+ */
+int mdb_set_relctx(MDB_txn *txn, MDB_dbi dbi, void *ctx);
+
/** Get items from a database.
* This function retrieves key/data pairs from the database. The address
* and length of the data associated with the specified \b key are returned
* If the database supports duplicate keys (#MDB_DUPSORT) then the
* first data item for the key will be returned. Retrieval of other
* items requires the use of #mdb_cursor_get().
+ *
+ * @note The memory pointed to by the returned values is owned by the
+ * database. The caller need not dispose of the memory, and may not
+ * modify it in any way. For values returned in a read-only transaction
+ * any modification attempts will cause a SIGSEGV.
* @param[in] txn A transaction handle returned by #mdb_txn_begin()
* @param[in] dbi A database handle returned by #mdb_open()
* @param[in] key The key to search for in the database
* @param[in] txn A transaction handle returned by #mdb_txn_begin()
* @param[in] dbi A database handle returned by #mdb_open()
* @param[in] key The key to store in the database
- * @param[in] data The data to store
+ * @param[in,out] data The data to store
* @param[in] flags Special options for this operation. This parameter
* must be set to 0 or by bitwise OR'ing together one or more of the
* values described here.
* <li>#MDB_NOOVERWRITE - enter the new key/data pair only if the key
* does not already appear in the database. The function will return
* #MDB_KEYEXIST if the key already appears in the database, even if
- * the database supports duplicates (#MDB_DUPSORT).
+ * the database supports duplicates (#MDB_DUPSORT). The \b data
+ * parameter will be set to point to the existing item.
* </ul>
* @return A non-zero error value on failure and 0 on success. Some possible
* errors are:
/** Create a cursor handle.
* Cursors are associated with a specific transaction and database and
* may not span threads.
- * @todo Cursors only support read operations. Support for cursor_put() and
- * cursor_del() needs to be added.
* @param[in] txn A transaction handle returned by #mdb_txn_begin()
* @param[in] dbi A database handle returned by #mdb_open()
* @param[out] cursor Address where the new #MDB_cursor handle will be stored
int mdb_cursor_get(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
MDB_cursor_op op);
+ /** Store by cursor.
+ * This function stores key/data pairs into the database.
+ * If the function fails for any reason, the state of the cursor will be
+ * unchanged. If the function succeeds and an item is inserted into the
+ * database, the cursor is always positioned to refer to the newly inserted item.
+ * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+ * @param[in] key The key operated on.
+ * @param[in] data The data operated on.
+ * @param[in] flags Options for this operation. This parameter
+ * must be set to 0 or one of the values described here.
+ * <ul>
+ * <li>#MDB_CURRENT - overwrite the data of the key/data pair to which
+ * the cursor refers with the specified data item. The \b key
+ * parameter is ignored.
+ * <li>#MDB_NODUPDATA - enter the new key/data pair only if it does not
+ * already appear in the database. This flag may only be specified
+ * if the database was opened with #MDB_DUPSORT. The function will
+ * return #MDB_KEYEXIST if the key/data pair already appears in the
+ * database.
+ * <li>#MDB_NOOVERWRITE - enter the new key/data pair only if the key
+ * does not already appear in the database. The function will return
+ * #MDB_KEYEXIST if the key already appears in the database, even if
+ * the database supports duplicates (#MDB_DUPSORT).
+ * </ul>
+ * @return A non-zero error value on failure and 0 on success. Some possible
+ * errors are:
+ * <ul>
+ * <li>EACCES - an attempt was made to modify a read-only database.
+ * <li>EINVAL - an invalid parameter was specified.
+ * </ul>
+ */
+int mdb_cursor_put(MDB_cursor *cursor, MDB_val *key, MDB_val *data,
+ unsigned int flags);
+
+ /** Delete current key/data pair
+ * This function deletes the key/data pair to which the cursor refers.
+ * @param[in] cursor A cursor handle returned by #mdb_cursor_open()
+ * @param[in] flags Options for this operation. This parameter
+ * must be set to 0 or one of the values described here.
+ * <ul>
+ * <li>#MDB_NODUPDATA - delete all of the data items for the current key.
+ * This flag may only be specified if the database was opened with #MDB_DUPSORT.
+ * </ul>
+ * @return A non-zero error value on failure and 0 on success. Some possible
+ * errors are:
+ * <ul>
+ * <li>EACCES - an attempt was made to modify a read-only database.
+ * <li>EINVAL - an invalid parameter was specified.
+ * </ul>
+ */
+int mdb_cursor_del(MDB_cursor *cursor, unsigned int flags);
+
/** Return count of duplicates for current key.
* This call is only valid on databases that support sorted duplicate
* data items #MDB_DUPSORT.
* <li>EINVAL - cursor is not initialized, or an invalid parameter was specified.
* </ul>
*/
-int mdb_cursor_count(MDB_cursor *cursor, unsigned long *countp);
+int mdb_cursor_count(MDB_cursor *cursor, size_t *countp);
/** Compare two data items according to a particular database.
* This returns a comparison as if the two data items were keys in the
*/
int mdb_cmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b);
+ /** Compare two data items according to a particular database.
+ * This returns a comparison as if the two items were data items of
+ * a sorted duplicates #MDB_DUPSORT database.
+ * @param[in] txn A transaction handle returned by #mdb_txn_begin()
+ * @param[in] dbi A database handle returned by #mdb_open()
+ * @param[in] a The first item to compare
+ * @param[in] b The second item to compare
+ * @return < 0 if a < b, 0 if a == b, > 0 if a > b
+ */
+int mdb_dcmp(MDB_txn *txn, MDB_dbi dbi, const MDB_val *a, const MDB_val *b);
+/** @} */
#endif /* _MDB_H_ */
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