From 90956050927382eeb2300bc11747dc1336963b68 Mon Sep 17 00:00:00 2001
From: Nolan Darilek <nolan@thewordnerd.info>
Date: Wed, 25 Aug 2021 12:48:00 -0500
Subject: [PATCH] Guard against overflows.

---
 src/map.rs | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/map.rs b/src/map.rs
index e89fc63..91a669c 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -111,15 +111,15 @@ impl Map {
         let mut exits = Vec::new();
 
         // Cardinal directions
-        if self.is_exit_valid(x-1, y) { exits.push((x-1, y, 1.0)) };
+        if x > 0 && self.is_exit_valid(x-1, y) { exits.push((x-1, y, 1.0)) };
         if self.is_exit_valid(x+1, y) { exits.push((x+1, y, 1.0)) };
-        if self.is_exit_valid(x, y-1) { exits.push((x, y-1, 1.0)) };
+        if y > 0 && self.is_exit_valid(x, y-1) { exits.push((x, y-1, 1.0)) };
         if self.is_exit_valid(x, y+1) { exits.push((x, y+1, 1.0)) };
 
         // Diagonals
-        if self.is_exit_valid(x-1, y-1) { exits.push((x-1, y-1, 1.45)); }
-        if self.is_exit_valid(x+1, y-1) { exits.push((x+1, y-1, 1.45)); }
-        if self.is_exit_valid(x-1, y+1) { exits.push((x-1, y+1, 1.45)); }
+        if x > 0 && y > 0 && self.is_exit_valid(x-1, y-1) { exits.push((x-1, y-1, 1.45)); }
+        if y > 0 && self.is_exit_valid(x+1, y-1) { exits.push((x+1, y-1, 1.45)); }
+        if x > 0 && self.is_exit_valid(x-1, y+1) { exits.push((x-1, y+1, 1.45)); }
         if self.is_exit_valid(x+1, y+1) { exits.push((x+1, y+1, 1.45)); }
 
         exits