From 40c7091386bd141d7165571c1a0e3403ab32fc10 Mon Sep 17 00:00:00 2001
From: Evan Hahn <me@evanhahn.com>
Date: Thu, 9 Nov 2023 09:20:48 -0600
Subject: [PATCH] GIF: parse terminator

---
 public/gif/constants.js | 2 ++
 public/gif/getNodeUi.js | 9 +++++++++
 public/gif/parseGif.js  | 4 ++++
 3 files changed, 15 insertions(+)

diff --git a/public/gif/constants.js b/public/gif/constants.js
index 7912516..c0bc867 100644
--- a/public/gif/constants.js
+++ b/public/gif/constants.js
@@ -43,6 +43,8 @@ const types = [
   "unknownExtensionBlock",
   "unknownExtensionBlockLabel",
   "unknownExtensionBlockData",
+
+  "gifTerminator",
 ].reduce((result, id) => {
   result[id] = id;
   return result;
diff --git a/public/gif/getNodeUi.js b/public/gif/getNodeUi.js
index c82117f..614c1f3 100644
--- a/public/gif/getNodeUi.js
+++ b/public/gif/getNodeUi.js
@@ -298,6 +298,15 @@ const NODE_UI_FNS = {
     title: "Unknown Extension Block Data",
     description: p("TODO"),
   }),
+
+  // Terminator
+
+  [GifNodeType.gifTerminator]: () => ({
+    title: "GIF Terminator",
+    description: p(
+      "The terminator is a one-byte block indicating the end of our GIF. We're done!",
+    ),
+  }),
 };
 
 /**
diff --git a/public/gif/parseGif.js b/public/gif/parseGif.js
index 3c173ac..d4ae67d 100644
--- a/public/gif/parseGif.js
+++ b/public/gif/parseGif.js
@@ -315,6 +315,10 @@ export default (bytes) => {
         readerFn = readExtensionBlock;
         break;
       case BLOCK_TYPE_TRAILER:
+        children.push({
+          type: GifNodeType.gifTerminator,
+          bytes: bytes.subarray(offset, offset + 1),
+        });
         break readingBlocks;
       default:
         throw new Error(`Unknown GIF block type: ${blockType}`);