From cc92d0e3166e7aab668919582a8ad639789e13d8 Mon Sep 17 00:00:00 2001
From: Cory McWilliams <cory@unprompted.com>
Date: Sun, 14 May 2023 18:47:19 +0000
Subject: [PATCH] Simplify magic bytes lookup slightly.

git-svn-id: https://www.unprompted.com/svn/projects/tildefriends/trunk@4296 ed5197a5-7fde-0310-b194-c3ffbd925b24
---
 core/core.js | 69 ++++++++++++++++++++++++----------------------------
 1 file changed, 32 insertions(+), 37 deletions(-)

diff --git a/core/core.js b/core/core.js
index a776298e..08d6ee54 100644
--- a/core/core.js
+++ b/core/core.js
@@ -7,6 +7,29 @@ let gProcessIndex = 0;
 let gProcesses = {};
 let gStatsTimer = false;
 
+const k_mime_types = {
+	'json': 'text/json',
+	'js': 'text/javascript',
+	'html': 'text/html',
+	'css': 'text/css',
+	'map': 'application/json',
+};
+
+const k_magic_bytes = [
+	{bytes: [0xff, 0xd8, 0xff, 0xdb], type: 'image/jpeg'},
+	{bytes: [0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46, 0x49, 0x46, 0x00, 0x01], type: 'image/jpeg'},
+	{bytes: [0xff, 0xd8, 0xff, 0xee], type: 'image/jpeg'},
+	{bytes: [0xff, 0xd8, 0xff, 0xe1, null, null, 0x45, 0x78, 0x69, 0x66, 0x00, 0x00], type: 'image/jpeg'},
+	{bytes: [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a], type: 'image/png'},
+	{bytes: [0x47, 0x49, 0x46, 0x38, 0x37, 0x61], type: 'image/gif'},
+	{bytes: [0x47, 0x49, 0x46, 0x38, 0x39, 0x61], type: 'image/gif'},
+	{bytes: [0x52, 0x49, 0x46, 0x46, null, null, null, null, 0x57, 0x45, 0x42, 0x50], type: 'image/webp'},
+	{bytes: [0x3c, 0x73, 0x76, 0x67], type: 'image/svg+xml'},
+	{bytes: [null, null, null, null, 0x66, 0x74, 0x79, 0x70, 0x6d, 0x70, 0x34, 0x32], type: 'audio/mpeg'},
+	{bytes: [null, null, null, null, 0x66, 0x74, 0x79, 0x70, 0x69, 0x73, 0x6f, 0x6d], type: 'video/mp4'},
+	{bytes: [null, null, null, null, 0x66, 0x74, 0x79, 0x70, 0x6d, 0x70, 0x34, 0x32], type: 'video/mp4'},
+];
+
 const k_global_settings = {
 	index: {
 		type: 'string',
@@ -488,14 +511,6 @@ async function staticFileHandler(request, response, blobId, uri) {
 	response.end("File not found");
 }
 
-const k_mime_types = {
-	'json': 'text/json',
-	'js': 'text/javascript',
-	'html': 'text/html',
-	'css': 'text/css',
-	'map': 'application/json',
-};
-
 async function staticDirectoryHandler(request, response, directory, uri) {
 	let filename = uri || 'index.html';
 	if (filename.indexOf('..') != -1) {
@@ -539,36 +554,16 @@ async function wellKnownHandler(request, response, path) {
 
 function sendData(response, data, type, headers) {
 	if (data) {
-		if (startsWithBytes(data, [0xff, 0xd8, 0xff, 0xdb]) ||
-			startsWithBytes(data, [0xff, 0xd8, 0xff, 0xe0, 0x00, 0x10, 0x4a, 0x46, 0x49, 0x46, 0x00, 0x01]) ||
-			startsWithBytes(data, [0xff, 0xd8, 0xff, 0xee]) ||
-			startsWithBytes(data, [0xff, 0xd8, 0xff, 0xe1, null, null, 0x45, 0x78, 0x69, 0x66, 0x00, 0x00])) {
-			response.writeHead(200, Object.assign({"Content-Type": "image/jpeg", "Content-Length": data.byteLength}, headers || {}));
-			response.end(data);
-		} else if (startsWithBytes(data, [0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a])) {
-			response.writeHead(200, Object.assign({"Content-Type": "image/png", "Content-Length": data.byteLength}, headers || {}));
-			response.end(data);
-		} else if (startsWithBytes(data, [0x47, 0x49, 0x46, 0x38, 0x37, 0x61]) ||
-			startsWithBytes(data, [0x47, 0x49, 0x46, 0x38, 0x39, 0x61])) {
-			response.writeHead(200, Object.assign({"Content-Type": "image/gif", "Content-Length": data.byteLength}, headers || {}));
-			response.end(data);
-		} else if (startsWithBytes(data, [0x52, 0x49, 0x46, 0x46, null, null, null, null, 0x57, 0x45, 0x42, 0x50])) {
-			response.writeHead(200, Object.assign({"Content-Type": "image/webp", "Content-Length": data.byteLength}, headers || {}));
-			response.end(data);
-		} else if (startsWithBytes(data, [0x3c, 0x73, 0x76, 0x67])) {
-			response.writeHead(200, Object.assign({"Content-Type": "image/svg+xml", "Content-Length": data.byteLength}, headers || {}));
-			response.end(data);
-		} else if (startsWithBytes(data, [null, null, null, null, 0x66, 0x74, 0x79, 0x70, 0x6d, 0x70, 0x34, 0x32])) {
-			response.writeHead(200, Object.assign({"Content-Type": "audio/mpeg", "Content-Length": data.byteLength}, headers || {}));
-			response.end(data);
-		} else if (startsWithBytes(data, [null, null, null, null, 0x66, 0x74, 0x79, 0x70, 0x69, 0x73, 0x6f, 0x6d]) ||
-			startsWithBytes(data, [null, null, null, null, 0x66, 0x74, 0x79, 0x70, 0x6d, 0x70, 0x34, 0x32])) {
-			response.writeHead(200, Object.assign({"Content-Type": "video/mp4", "Content-Length": data.byteLength}, headers || {}));
-			response.end(data);
-		} else {
-			response.writeHead(200, Object.assign({"Content-Type": type || "application/binary", "Content-Length": data.byteLength}, headers || {}));
-			response.end(data);
+		for (let magic of k_magic_bytes) {
+			if (startsWithBytes(data, magic.bytes)) {
+				response.writeHead(200, Object.assign({"Content-Type": magic.content_type, "Content-Length": data.byteLength}, headers || {}));
+				response.end(data);
+				return;
+			}
 		}
+
+		response.writeHead(200, Object.assign({"Content-Type": type || "application/binary", "Content-Length": data.byteLength}, headers || {}));
+		response.end(data);
 	} else {
 		response.writeHead(404, Object.assign({"Content-Type": "text/plain; charset=utf-8", "Content-Length": "File not found".length}, headers || {}));
 		response.end("File not found");