BLOBs

BLOBs — Management of BLOBs (Binary Large OBjects)

Synopsis




            GdaBlob;
enum        GdaBlobMode;
gint        gda_blob_open                   (GdaBlob *blob,
                                             GdaBlobMode mode);
gint        gda_blob_read                   (GdaBlob *blob,
                                             gpointer buf,
                                             gint size,
                                             gint *bytes_read);
gint        gda_blob_write                  (GdaBlob *blob,
                                             gpointer buf,
                                             gint size,
                                             gint *bytes_written);
gint        gda_blob_lseek                  (GdaBlob *blob,
                                             gint offset,
                                             gint whence);
gint        gda_blob_close                  (GdaBlob *blob);
gint        gda_blob_remove                 (GdaBlob *blob);
gchar*      gda_blob_get_sql_id             (GdaBlob *blob);

Object Hierarchy


  GObject
   +----GdaBlob

Description

Details

GdaBlob

typedef struct _GdaBlob GdaBlob;

enum GdaBlobMode

typedef enum {
	GDA_BLOB_MODE_READ = 1,
	GDA_BLOB_MODE_WRITE = 1 << 1,
	GDA_BLOB_MODE_RDWR = 0x03 
} GdaBlobMode;

gda_blob_open ()

gint        gda_blob_open                   (GdaBlob *blob,
                                             GdaBlobMode mode);

Opens an existing BLOB. The BLOB must be initialized by gda_connection_create_blob or obtained from a GValue.

blob : an existing GdaBlob
mode : see GdaBlobMode.
Returns : 0 if everything's ok. In case of error, -1 is returned and the provider should have added an error (a GdaConnectionEvent) to the connection.

gda_blob_read ()

gint        gda_blob_read                   (GdaBlob *blob,
                                             gpointer buf,
                                             gint size,
                                             gint *bytes_read);

Reads a chunk of bytes from the BLOB into a user-provided location.

blob : a GdaBlob which is opened with the flag GDA_BLOB_MODE_READ set.
buf : buffer to read the data into.
size : maximum number of bytes to read.
bytes_read : on return it will point to the number of bytes actually read.
Returns : 0 if everything's ok. In case of error, -1 is returned and the provider should have added an error to the connection.

gda_blob_write ()

gint        gda_blob_write                  (GdaBlob *blob,
                                             gpointer buf,
                                             gint size,
                                             gint *bytes_written);

Writes a chunk of bytes from a user-provided location to the BLOB.

blob : a GdaBlob which is opened with the flag GDA_BLOB_MODE_WRITE set.
buf : buffer to write the data from.
size : maximum number of bytes to read.
bytes_written : on return it will point to the number of bytes actually written.
Returns : 0 if everything's ok. In case of error, -1 is returned and the provider should have added an error to the connection.

gda_blob_lseek ()

gint        gda_blob_lseek                  (GdaBlob *blob,
                                             gint offset,
                                             gint whence);

Sets the blob read/write position.

blob : a opened GdaBlob.
offset : offset added to the position specified by whence.
whence : SEEK_SET, SEEK_CUR or SEEK_END with the same meaning as in fseek(3).
Returns : the current position in the blob or < 0 in case of error. In case of error the provider should have added an error to the connection.

gda_blob_close ()

gint        gda_blob_close                  (GdaBlob *blob);

Closes the BLOB. After calling this function, blob should no longer be used.

blob : a opened GdaBlob.
Returns : 0 if everything's ok. In case of error, -1 is returned and the provider should have added an error to the connection.

gda_blob_remove ()

gint        gda_blob_remove                 (GdaBlob *blob);

Removes the BLOB from the database. After calling this function, blob should no longer be used.

blob : a valid GdaBlob.
Returns : 0 if everything's ok. In case of error, -1 is returned and the provider should have added an error to the connection.

gda_blob_get_sql_id ()

gchar*      gda_blob_get_sql_id             (GdaBlob *blob);

blob : a valid GdaBlob.
Returns : a string representation of a blob's SQL ID.