From 0895a25ffa531ec5786d8f0b7e0d585d95d8e81e Mon Sep 17 00:00:00 2001
From: Kevin Lamonte <kevin.lamonte@gmail.com>
Date: Fri, 8 Feb 2019 10:07:03 -0600
Subject: [PATCH] #37 fix signed byte type math

---
 src/jexer/net/TelnetInputStream.java | 24 ++++++++++++++++++++----
 1 file changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/jexer/net/TelnetInputStream.java b/src/jexer/net/TelnetInputStream.java
index 056a7dc8..ac010e8f 100644
--- a/src/jexer/net/TelnetInputStream.java
+++ b/src/jexer/net/TelnetInputStream.java
@@ -926,25 +926,41 @@ public class TelnetInputStream extends InputStream implements SessionInfo {
                 if (subnegBuffer.get(i) == (byte)TELNET_IAC) {
                     i++;
                 }
-                windowWidth = subnegBuffer.get(i) * 256;
+                int width = subnegBuffer.get(i);
+                if (width < 0) {
+                    width += 256;
+                }
+                windowWidth = width * 256;
 
                 i++;
                 if (subnegBuffer.get(i) == (byte)TELNET_IAC) {
                     i++;
                 }
-                windowWidth += subnegBuffer.get(i);
+                width = subnegBuffer.get(i);
+                windowWidth += width;
+                if (width < 0) {
+                    windowWidth += 256;
+                }
 
                 i++;
                 if (subnegBuffer.get(i) == (byte)TELNET_IAC) {
                     i++;
                 }
-                windowHeight = subnegBuffer.get(i) * 256;
+                int height = subnegBuffer.get(i);
+                if (height < 0) {
+                    height += 256;
+                }
+                windowHeight = height * 256;
 
                 i++;
                 if (subnegBuffer.get(i) == (byte)TELNET_IAC) {
                     i++;
                 }
-                windowHeight += subnegBuffer.get(i);
+                height = subnegBuffer.get(i);
+                windowHeight += height;
+                if (height < 0) {
+                    windowHeight += 256;
+                }
             }
             break;
 
-- 
2.27.0