[Octave-bug-tracker] [bug #61300] integer range might exceed upper limit

[Arun Giridhar]

Follow-up Comment #23, bug #61300 (project octave):

Yes, you are right: the problem in the previous test (comment #21) was the
values were too close to intmax. Reducing the values seems to work better:


octave:1> uint64(0) : uint64(1e18) : uint64(1e19)
ans =

 Columns 1 through 6:

                     0   1000000000000000000   2000000000000000000  
3000000000000000000   4000000000000000000   5000000000000000000

 Columns 7 through 11:

   6000000000000000000   7000000000000000000   8000000000000000000  
9000000000000000000  10000000000000000000

octave:2> int64(0) : int64(1e17) : int64(1e18)
ans =

 Columns 1 through 6:

                    0   100000000000000000   200000000000000000  
300000000000000000   400000000000000000   500000000000000000

 Columns 7 through 11:

   600000000000000000   700000000000000000   800000000000000000  
900000000000000000  1000000000000000000


Converged patch:


diff -r 3c4639e42855 liboctave/array/Range.h
--- a/liboctave/array/Range.h   Fri Nov 26 16:22:19 2021 -0800
+++ b/liboctave/array/Range.h   Sun Nov 28 14:54:56 2021 -0500
@@ -325,8 +325,9 @@
       m_numel = ((m_increment == T (0)
                   || (m_limit > m_base && m_increment < T (0))
                   || (m_limit < m_base && m_increment > T (0)))
-                 ? T (0)
-                 : (m_limit - m_base + m_increment) / m_increment);
+                 ? 0
+                 : (m_limit.value () - m_base.value () + m_increment.value
())
+                   / m_increment.value ());
 
       m_final = m_base + (m_numel - 1) * m_increment;
     }


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