From 9be66afce76bd50851411508579a69e8be94cfb2 Mon Sep 17 00:00:00 2001
From: SukkaW <isukkaw@gmail.com>
Date: Wed, 19 Mar 2025 23:56:52 +0800
Subject: [PATCH] Perf: simplify file equal

---
 Build/lib/create-file.test.ts | 16 ++++++++++++++--
 Build/lib/create-file.ts      | 24 +++++++++---------------
 2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/Build/lib/create-file.test.ts b/Build/lib/create-file.test.ts
index 46cd42ef..7d1538aa 100644
--- a/Build/lib/create-file.test.ts
+++ b/Build/lib/create-file.test.ts
@@ -57,15 +57,27 @@ describe('fileEqual', () => {
     false
   ));
 
-  it('eol more', () => test(
+  it('eol more #1', () => test(
     ['A', 'B'],
     ['A', 'B', ''],
     false
   ));
 
-  it('eol less', () => test(
+  it('eol more #2', () => test(
+    ['A', 'B', ''],
+    ['A', 'B', '', ''],
+    false
+  ));
+
+  it('eol less #1', () => test(
     ['A', 'B', ''],
     ['A', 'B'],
     false
   ));
+
+  it('eol less #2', () => test(
+    ['A', 'B', '', ''],
+    ['A', 'B', ''],
+    false
+  ));
 });
diff --git a/Build/lib/create-file.ts b/Build/lib/create-file.ts
index 7582dca2..28904b0c 100644
--- a/Build/lib/create-file.ts
+++ b/Build/lib/create-file.ts
@@ -17,22 +17,24 @@ export async function fileEqual(linesA: string[], source: AsyncIterable<string>
   for await (const lineB of source) {
     index++;
 
+    // b become bigger
     if (index > maxIndexA) {
       return false;
     }
 
     const lineA = linesA[index];
 
-    const lineAIsComment = isCommentLine(lineA);
-    const lineBIsComment = isCommentLine(lineB);
-
-    if (lineAIsComment !== lineBIsComment) {
+    const aFirstChar = lineA.charCodeAt(0);
+    if (aFirstChar !== lineB.charCodeAt(0)) {
       return false;
     }
 
-    // Now both line are either both comment or both not comment
+    // Now both line has the same first char
     // We only need to compare one of them
-    if (lineAIsComment) {
+    if (
+      aFirstChar === 35 // #
+      || aFirstChar === 33 // !
+    ) {
       continue;
     }
 
@@ -41,18 +43,10 @@ export async function fileEqual(linesA: string[], source: AsyncIterable<string>
     }
   }
 
+  // b is not smaller than a
   return index === maxIndexA;
 }
 
-export function isCommentLine(line: string): boolean {
-  const firstChar = line.charCodeAt(0);
-  return (
-    firstChar === 35 // #
-    || firstChar === 33 // !
-    || (firstChar === 47 && line[1] === '/' && line[3] === '#') // //##
-  );
-}
-
 export async function compareAndWriteFile(span: Span, linesA: string[], filePath: string) {
   const linesALen = linesA.length;