reading of decimal(18, 5) gets corrupted

[vizcay]

I've been caught by a very strange bug at my production server related to decimal fields:

• Reading values bigger than 20000 (aprox) gets trash.
• The issue only occurs with decimal(18, 5) fields.. but decimal(18, 2) fields work fine, haven't tested others.
• The data is well written and correct at the db, I can check that using isql directly, the problem is when is read by fb.
• I'm pretty sure the bug lurks at the fb gem (isql works fine and fb-activerecord-adapter is bypassed).
• Strange enough I wasn't able to reproduce this bug at my dev machine.. but I've found why: it's a x86_64 architecture, and my production server is x86.
• decimal(18, x) gets stored as 64bit integers, I think that fb is messing the math of the scale in some way that only affects 32bits arquitectures.
• Maybe "static VALUE fb_cursor_fetch(struct FbCursor *fb_cursor)" at fb.c@1961 is the culprit ? Maybe the conditional compilation switched by HAVE_LONG_LONG is related?

How to reproduce (32bit architecture needed):

require 'fb'
include Fb
db = Database.new(:database => "#{File.expand_path(File.dirname(__FILE__))}/test.fdb", :username => 'sysdba', :password => 'masterkey')
conn = db.connect rescue db.create.connect
conn.execute("create table TEST (ID int not null primary key, N decimal(18, 5))") if !conn.table_names.include?("TEST")
conn.execute("delete from TEST")
conn.execute("insert into TEST values (?, ?)", 1, 50000)
puts "50000 = #{conn.query(:hash, "select * from TEST").first['N']} ?"

At my production server I get: "50000 = 7050.32704 ?" and at my dev machine of course: "50000 = 50000.0 ?"

[rowland]

Fixed. Thanks for the report.

[vizcay]

Thanks Rowland!