From 5eab8ec610d82ff842de8a342663d40b41ffe678 Mon Sep 17 00:00:00 2001
From: Calixte Denizet <calixte.denizet@gmail.com>
Date: Fri, 14 Apr 2023 15:07:31 +0200
Subject: [PATCH] Avoid when it's possible to use Array.concat when compiling a
 CFF font

In looking at https://bugs.ghostscript.com/show_bug.cgi?id=706451 I noticed that bug2.pdf was pretty
slow to load for such a basic file.
In profiling I noticed that a lot of time is spent in Array.concat, hence this patch use Array.push when
it's possible (it's now ~3 times faster).
---
 src/core/cff_parser.js | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/core/cff_parser.js b/src/core/cff_parser.js
index d61a7f514..c1ce00c9c 100644
--- a/src/core/cff_parser.js
+++ b/src/core/cff_parser.js
@@ -1383,7 +1383,13 @@ class CFFCompiler {
       data: [],
       length: 0,
       add(data) {
-        this.data = this.data.concat(data);
+        if (data.length <= 65536) {
+          // The number of arguments is limited, hence we just take 65536 as
+          // limit because it isn't too high or too low.
+          this.data.push(...data);
+        } else {
+          this.data = this.data.concat(data);
+        }
         this.length = this.data.length;
       },
     };