Fix some cases where we're shifting a signed 1 left.

Shift 1U instead, to make sure it's unsigned; the result of, for
example, the result of shifting a signed value left is undefined if the
value times 2^{shift count} doesn't fit in the *signed* type of the
shifted value.  That means, in particular, that the result of shifting 1
left by {number of bits in an int - 1} is undefined.  (In *practice*,
it'll probably be -2^32, with the bit you want set, but that's not
guaranteed, and GCC 5.1 seems not to like it.)

Change-Id: I0d27565c382a04ceda9eec65f45a430ceb74cf53
Reviewed-on: https://code.wireshark.org/review/8255
Reviewed-by: Guy Harris <guy@alum.mit.edu>

1 files changed, 3 insertions, 3 deletions

diff --git a/mkcap.c b/mkcap.c
index a7cefdf92e..0f0a7a58ee 100644
--- a/mkcap.c
+++ b/mkcap.c
@@ -153,7 +153,7 @@ int next_ack_due()
   int ack_lost = 0, seg_lost = 0;
 
   if (next_slot == first_slot)
-    return (((unsigned int)(1<<31)) - 1);
+    return ((1U<<31) - 1);
 
   /*
    * Figure out if we need to issue an ACK. We skip all outstanding packets
@@ -178,7 +178,7 @@ int next_ack_due()
   }
 
   if (slot == next_slot)
-    return (((unsigned int)(1<<31)) - 1);
+    return ((1U<<31) - 1);
 
   /*
    * If there is only one slot occupied, or a segment was lost then
@@ -206,7 +206,7 @@ int next_ack_due()
       if (((first_slot + 1 + 2 * ack_lost) % SEG_HIST_SIZE) >= next_slot)
         /* XXX: FIXME, what about when the window is closed */
         /* XXX: FIXME, use the correct value for this       */
-        return (((unsigned int)(1<<31)) - 1);
+        return ((1U<<31) - 1);
       else
         return seg_hist[(first_slot + 1 + 2 * ack_lost) % SEG_HIST_SIZE].ts +
           ack_delay + jitter;