FBUDF, a small project to enhance ibudf.

The library ibudf that comes with IB5, IB6 and FB has some generic routines.
However, it lacks others and it seems a good idea to enhance it with more
functionality. The first test is to build a separate small library. When those
functions have been tested, they may be included in ibudf. This way, it's possible
to experiment with fbudf without mangling the established library.

This is initially a MSVC project for Windows. It will be generalized later.
It doesn't use ib_util because it relies on the engine providing return
arguments when they are of type string.

Originally, this library intends to offer:

NVL => one for integers and the other for strings. This way, the overhead
for strings can be avoided for integers.

NULLIF => same idea than before.

DOW (Day of Week) Monday, Tuesday, Wednesday ...
SDOW(Short Day of Week)  Mon, Tue, Wed, Thu ....

(
The following two aren't necessary:
SUBSTR: It has been superseded by internal SUBSTRING in Firebird.
LEFT: You can use SUBSTRING(s from 1 for N) in Firebird
)

RIGHT: This will work only for 1-byte charsets.

TRUNCATE / ROUND 

(
The following two are already in udflib:
CEILING / FLOOR
)

Date manipulation stuff ...
  Add a day, week, month, year to a date.

String <-> BLOB
  STRING2BLOB
(Firebird already is capable of accepting a string to populate a blob on INSERT only.)

---
Claudio Valderrama - July 2001.

