Hi Raf,
I've written a UDF library for both Windows and Linux to do blob
stuff. Its available at http://www.cvalde.com/utilities/wmBlobUDF.zip

I'm not sure if this was the final version or not but I've been
using it for ages now on IB6, Firebird 0.94, RC2 both windows and
linux.

My versions got the following functions in it.

BLOB_TO_STRING
Converts a blob to its string representation. Ensure the CSTRING
is declared big enough for the returned string.

BLOB_LENGTH
Returns the length of a blob.

BLOB_SUBSTR
Converts a blob to its string representation and returns a substring
starting at startpos and ending with endpos. Ensure the CSTRING
is declared big enough for the returned string.

BLOB_LEFT
Converts a blob to its string representation and returns the
leftmost characters. Ensure the CSTRING is declared big enough
for the returned string.

BLOB_RIGHT
Converts a blob to its string representation and returns the
rightmost characters. Ensure the CSTRING is declared big enough
for the returned string.

STRING_TO_BLOB
Converts a string to a blob.

BLOB_APPEND_STRING
Appends the given string to the end of the blob.

BLOB_INSERT_STRING
Inserts the given string at the given position in the blob.

BLOB_COMPARE
Compares two blobs (Binary comparison) and returns 0 if identical,
otherwise returns the index of the first differing character.

BLOB_DELETE_CHARS
Removes characters from within a blob, starting at startpos and
ending with endpos.

BLOB_STRING_POS
Returns the index of the first matching character from the search
string in the blob, or 0 if it is not found.

BLOB_STRIPTAGS
Returns a blob with all HTML/XML/SGML tags removed.

BLOB_REPLACE_TOKENS
Returns a blob with the specified tokens replaced by the replace
string

Regards Ian Newby.