added patch to address underflow when -n is not a multiple of -l

from Nathan Jones: https://sourceforge.net/tracker/index.php?func=detail&aid=1943432&group_id=128336&atid=711373

AUTHORS

@@ -28,3 +28,6 @@ Andrew Gallatin <gallatin@gmail.com>
 
 Stephen Hemminger <shemminger@linux-foundation.org>
   * Linux congestion control selection and theading improvements
+
+Nathan Jones <nmjones@users.sourceforge.net>
+  * patch for underflow when value specified in -n is not a multiple of -l

ChangeLog

@@ -1,3 +1,9 @@
+2008-05-09 Nathan Jones <nmjones@users.sourceforge.net>
+
+* prevent underflow when the amount of data to be transmitted (-n) is not a
+multiple of the buffer size (-l)  Patch:
+https://sourceforge.net/tracker/index.php?func=detail&aid=1943432&group_id=128336&atid=711373
+
 2008-04-08 Jon Dugan <jdugan@x1024.net>
 
 * print report headers only once

src/Client.cpp

@@ -170,7 +170,12 @@ void Client::RunTCP( void ) {
         }	
 
         if ( !mMode_Time ) {
-            mSettings->mAmount -= currLen;
+            /* mAmount may be unsigned, so don't let it underflow! */
+            if( mSettings->mAmount >= currLen ) {
+                mSettings->mAmount -= currLen;
+            } else {
+                mSettings->mAmount = 0;
+            }
         }
 
     } while ( ! (sInterupted  || 
@@ -310,7 +315,12 @@ void Client::Run( void ) {
             delay_loop( delay ); 
         }
         if ( !mMode_Time ) {
-            mSettings->mAmount -= currLen;
+            /* mAmount may be unsigned, so don't let it underflow! */
+            if( mSettings->mAmount >= currLen ) {
+                mSettings->mAmount -= currLen;
+            } else {
+                mSettings->mAmount = 0;
+            }
         }
 
     } while ( ! (sInterupted  ||