From 78b039be58142c755571b661f57400bc92ad2fd5 Mon Sep 17 00:00:00 2001
From: CJ van den Berg <cj@vdbonline.com>
Date: Tue, 3 Dec 2024 19:51:07 +0100
Subject: [PATCH] fix: integer overflow crashes with large screen sizes > u16

---
 build.zig.zon    |  4 ++--
 src/tui/home.zig | 20 ++++++++++----------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/build.zig.zon b/build.zig.zon
index a281e3c..abc3aa2 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -30,8 +30,8 @@
             .hash = "122019f077d09686b1ec47928ca2b4bf264422f3a27afc5b49dafb0129a4ceca0d01",
         },
         .vaxis = .{
-            .url = "https://github.com/neurocyte/libvaxis/archive/352fa9c89d6339325b9f851b9a27e62ec79ba33c.tar.gz",
-            .hash = "1220e604b723781b4a306db5801eee419a689b4d470232a1bacc525f45f00d455b1a",
+            .url = "https://github.com/neurocyte/libvaxis/archive/ffe35b4342bd2913efd46c35c0ccd15544ac87e6.tar.gz",
+            .hash = "12202ee9842d28927674e552f1ea41e2c41e59f6b4b5d290de9b6fd626fd332ac627",
         },
         .zeit = .{
             .url = "https://github.com/rockorager/zeit/archive/9cca8ec620a54c3b07cd249f25e5bcb3153d03d7.tar.gz",
diff --git a/src/tui/home.zig b/src/tui/home.zig
index 5ec6a1a..9657743 100644
--- a/src/tui/home.zig
+++ b/src/tui/home.zig
@@ -228,12 +228,12 @@ const Fire = struct {
     //scope cache - spread fire
     spread_px: u8 = 0,
     spread_rnd_idx: u8 = 0,
-    spread_dst: u16 = 0,
+    spread_dst: usize = 0,
 
     FIRE_H: u16,
     FIRE_W: u16,
-    FIRE_SZ: u16,
-    FIRE_LAST_ROW: u16,
+    FIRE_SZ: usize,
+    FIRE_LAST_ROW: usize,
 
     screen_buf: []u8,
 
@@ -254,12 +254,12 @@ const Fire = struct {
             }),
             .FIRE_H = FIRE_H,
             .FIRE_W = FIRE_W,
-            .FIRE_SZ = FIRE_H * FIRE_W,
-            .FIRE_LAST_ROW = (FIRE_H - 1) * FIRE_W,
-            .screen_buf = try allocator.alloc(u8, FIRE_H * FIRE_W),
+            .FIRE_SZ = @as(usize, @intCast(FIRE_H)) * FIRE_W,
+            .FIRE_LAST_ROW = @as(usize, @intCast(FIRE_H - 1)) * FIRE_W,
+            .screen_buf = try allocator.alloc(u8, @as(usize, @intCast(FIRE_H)) * FIRE_W),
         };
 
-        var buf_idx: u16 = 0;
+        var buf_idx: usize = 0;
         while (buf_idx < self.FIRE_SZ) : (buf_idx += 1) {
             self.screen_buf[buf_idx] = fire_black;
         }
@@ -289,7 +289,7 @@ const Fire = struct {
         while (doFire_x < self.FIRE_W) : (doFire_x += 1) {
             var doFire_y: u16 = 0;
             while (doFire_y < self.FIRE_H) : (doFire_y += 1) {
-                const doFire_idx: u16 = doFire_y * self.FIRE_W + doFire_x;
+                const doFire_idx = @as(usize, @intCast(doFire_y)) * self.FIRE_W + doFire_x;
 
                 //spread fire
                 self.spread_px = self.screen_buf[doFire_idx];
@@ -328,8 +328,8 @@ const Fire = struct {
                 //each character rendered is actually to rows of 'pixels'
                 // - "hi" (current px row => fg char)
                 // - "low" (next row => bg color)
-                const px_hi = self.screen_buf[frame_y * self.FIRE_W + frame_x];
-                const px_lo = self.screen_buf[(frame_y + 1) * self.FIRE_W + frame_x];
+                const px_hi = self.screen_buf[@as(usize, @intCast(frame_y)) * self.FIRE_W + frame_x];
+                const px_lo = self.screen_buf[@as(usize, @intCast(frame_y + 1)) * self.FIRE_W + frame_x];
 
                 self.plane.set_fg_palindex(fire_palette[px_hi]) catch {};
                 self.plane.set_bg_palindex(fire_palette[px_lo]) catch {};