SQL & PL/SQL

I have a BLOB column which contains BASE64 encoded jpegs.

I want to decode these from BASE64 such that I can get the original JPEG.

I've written a function to do this (based on an example found here but modified slightly since my source is a BLOB not a CLOB: http://blogs.dayneo.co.za/2012/07/base64-decode-using-plsql.html)

	FUNCTION base64_decode(p_file IN BLOB) 
	RETURN BLOB IS
	
	 l_BASE64_LN_LENGTH constant pls_integer := 30000;
	 l_result           blob := empty_blob();
	 l_pos              number := 1;
	 l_amount           number;
	 l_buffer           raw(32767);
	 l_rbuf             raw(32767);
	 l_length           pls_integer;
	
	begin
	
	 DBMS_LOB.createTemporary(l_result, true, dbms_lob.CALL);
	 
	 l_length  := DBMS_LOB.getLength(p_file);
	 
	 while l_pos <= l_length loop
	
	  l_amount := l_BASE64_LN_LENGTH;
	  
	  dbms_lob.read(p_file, l_amount, l_pos, l_rbuf);
	  
	  l_buffer := utl_encode.base64_decode(l_rbuf);
	
	  dbms_lob.writeappend(l_result, 
	                       utl_raw.length(l_buffer), 
	                       l_buffer);
	 
	  l_pos    := l_pos + l_BASE64_LN_LENGTH;
	
	 end loop;
	
	 return l_result;
	 
	END base64_decode;

This works absolutely fine where the input BLOB (p_file) is less than 30000 bytes i.e. I can save the generated BLOB and open it in a graphics application.

However, if the input BLOB (p_file) is larger than 30000 bytes, when I save the resultant BLOB (i.e. l_result) and try to open it with a graphics application such as Windows Picture Viewer I get the message "Drawing failed".



Any thoughts, comments or suggestions would be very much appreciated.

Thanks,
Andy