RandomDataImpl nextInt(int, int) nextLong(long, long)
-----------------------------------------------------

                 Key: MATH-153
                 URL: http://issues.apache.org/jira/browse/MATH-153
             Project: Commons Math
          Issue Type: Bug
    Affects Versions: Nightly Builds, 1.1 Final
            Reporter: Remi Arntzen
            Priority: Critical


RandomDataImpl.nextInt(Integer.MIN_VALUE, Integer.MAX_VALUE) suffers from 
overflow errors.

change
return lower + (int) (rand.nextDouble() * (upper - lower + 1));
to
return (int) (lower + (long) (rand.nextDouble()*((long) upper - lower + 1)));

additional checks must be made for the nextlong(long, long) method.
At first I thought about using MathUtils.subAndCheck(long, long) but there is 
only an int version avalible, and the problem is that subAndCheck internaly 
uses long values to check for overflow just as my previous channge proposes.  
The only thing I can think of is using a BigInteger to check for the number of 
bits required to express the difference.

-- 
This message is automatically generated by JIRA.
-
If you think it was sent incorrectly contact one of the administrators: 
http://issues.apache.org/jira/secure/Administrators.jspa
-
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

---------------------------------------------------------------------
To unsubscribe, e-mail: [EMAIL PROTECTED]
For additional commands, e-mail: [EMAIL PROTECTED]

Reply via email to