# HG changeset patch
# User Maged Rifaat <magedrifaat@gmail.com>
# Date 1661600504 -7200
# Node ID a81fad5c9fef4cf39437ad7d9660cc1eb0a4910b
# Parent  4c2b83516eb719e23e11c2701ace432137e59ed6
idx_vector: Fix wrong length calculation (bug #62968).

* liboctave/array/idx-vector.cc: Fix wrong calculation for m_len in
(start, limit, step) constructor to account for incomplete intervals.

* liboctave/array/idx-vector.h: Add comment to (start, limit, step) constructor.

diff -r 4c2b83516eb7 -r a81fad5c9fef liboctave/array/idx-vector.cc
--- a/liboctave/array/idx-vector.cc	Fri Aug 26 22:30:43 2022 +0200
+++ b/liboctave/array/idx-vector.cc	Sat Aug 27 13:41:44 2022 +0200
@@ -103,8 +103,10 @@
                                             octave_idx_type limit,
                                             octave_idx_type step)
     : idx_base_rep (), m_start(start),
-      m_len (step ? std::max ((limit - start) / step,
-                              static_cast<octave_idx_type> (0))
+      // Round length away from zero to catch incomplete intervals
+      m_len (step
+             ? std::max ((limit - start + step - (step > 0 ? 1 : -1)) / step,
+                         static_cast<octave_idx_type> (0))
              : -1),
       m_step (step)
   {
diff -r 4c2b83516eb7 -r a81fad5c9fef liboctave/array/idx-vector.h
--- a/liboctave/array/idx-vector.h	Fri Aug 26 22:30:43 2022 +0200
+++ b/liboctave/array/idx-vector.h	Sat Aug 27 13:41:44 2022 +0200
@@ -171,7 +171,8 @@
                      octave_idx_type step, direct)
         : idx_base_rep (), m_start (start), m_len (len), m_step (step) { }
 
-      // Zero-based constructor.
+      // Zero-based constructor for index range starting at `start` (inclusive)
+      // and ending at `limit` (exclusive) in steps of `step`.
       idx_range_rep (octave_idx_type start, octave_idx_type limit,
                      octave_idx_type step);