Hi! I am trying to convert a BLOB (unlimited size, theoretically) to a long VARCHAR (say, VARCHAR(8192)). This should be easy enough to do:
DECLARE VARIABLE b BLOB; /* input */ DECLARE VARIABLE v VARCHAR(8192); /* output */ ... v = SUBSTRING(b, 1, 8192); Except that as soon as I convert between BLOB and VARCHAR, I lose all high-ASCII characters (they get replaced by a dot). E.g., to expand the example above: DECLARE VARIABLE b BLOB; /* input */ DECLARE VARIABLE b2 BLOB; /* output */ DECLARE VARIABLE v VARCHAR(8192); /* output */ ... v = SUBSTRING(b, 1, 8192); b2 = SUBSTRING(b, 1, 8192); When this code is run, both b2 and v contain the first 8192 characters from the input - but in v's case, the high-ascii characters get converted to a dot. Supposedly this should be done using a UDF, but I just can't figure out how to write one (in Delphi): function BLOBSTR(Value: PBlob; Size: Longint; Dest: PAnsiChar): PAnsiChar; cdecl; begin Result := Dest; FillChar(Result^, Size, 'a'); end; (I decided to remove the BLOB-reading code to make sure I have no errors in my parameter-passing code.) But with a declaration: DECLARE EXTERNAL FUNCTION BLOBSTR BLOB, INTEGER, CSTRING(8192) RETURNS PARAMETER 3 ENTRY_POINT 'BLOBSTR' MODULE_NAME 'pwIBUDF'; and a select: SELECT BLOBSTR(blobfield, 10) FROM sometable WHERE id=1 I get an empty (zero-byte, NOT NULL) result. I would expect to get either a 10-byte result (if the buffer for parameter 3 gets filled with zeroes before the UDF is called) or something between 10 and 8192 byte result (if the buffer does not get initialized), but zero has me stumped. I would appreciate any pointers. Thanks, Pepak ------------------------------------ ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Visit http://www.firebirdsql.org and click the Resources item on the main (top) menu. Try Knowledgebase and FAQ links ! Also search the knowledgebases at http://www.ibphoenix.com ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/firebird-support/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/firebird-support/join (Yahoo! ID required) <*> To change settings via email: firebird-support-dig...@yahoogroups.com firebird-support-fullfeatu...@yahoogroups.com <*> To unsubscribe from this group, send an email to: firebird-support-unsubscr...@yahoogroups.com <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
