Ensure that the step size for integer parameter ranges is always

positive.

Cast to unsigned int when checking whether the parameter value
complies with the step size.  Explain why this is necessary.


git-svn-id: http://svn.cactuscode.org/flesh/trunk@4119 17b73243-c579-4c4c-a9d2-2d5706c11dac

1 files changed, 9 insertions, 1 deletions

diff --git a/src/util/Misc.c b/src/util/Misc.c
index 382b7226..9d92a447 100644
--- a/src/util/Misc.c
+++ b/src/util/Misc.c
@@ -439,6 +439,11 @@ int Util_IntInRange(int inval, const char *range)
       /* No step given, so default to 1. */
       step = 1;
     }
+    if (step <= 0)
+    {
+      CCTK_Warn(1, __LINE__, __FILE__, "Flesh", "Invalid step");
+      step = 1;
+    }
 
     /* Finally work out if the range is closed at the upper end. */
     if(pmatch[5].rm_so != -1)
@@ -455,9 +460,12 @@ int Util_IntInRange(int inval, const char *range)
       end_closed = 1;
     }
 
+    /* Cast to unsigned int, because the subtraction (inval - start)
+       can overflow, and wrap-around is legal in C only for unsigned
+       types.  */
     if(inval >= start + !start_closed &&
        inval <= end   - !end_closed   &&
-       ! ((inval-start) % step))
+       ! (((unsigned int)inval-(unsigned int)start) % (unsigned int)step))
     {
       retval = 1;
     }