Improve performance of arrayBufferToBinaryString (#3121)

Co-authored-by: Antti Palola <antti.palola@vincit.fi>
Co-authored-by: 101arrowz <arjunbarrett@gmail.com>
Co-authored-by: Lukas Holländer <lukas.hollaender@yworks.com>

src/modules/addimage.js

@@ -43,6 +43,11 @@ import { atob, btoa } from "../libs/AtobBtoa.js";
 
   var UNKNOWN = "UNKNOWN";
 
+  // Heuristic selection of a good batch for large array .apply. Not limiting make the call overflow.
+  // With too small batch iteration will be slow as more calls are made,
+  // higher values cause larger and slower garbage collection.
+  var ARRAY_APPLY_BATCH = 8192;
+
   var imageFileTypeHeaders = {
     PNG: [[0x89, 0x50, 0x4e, 0x47]],
     TIFF: [
@@ -731,27 +736,27 @@ import { atob, btoa } from "../libs/AtobBtoa.js";
    * @name arrayBufferToBinaryString
    * @public
    * @function
-   * @param {ArrayBuffer} ArrayBuffer with ImageData
+   * @param {ArrayBuffer|ArrayBufferView} ArrayBuffer buffer or bufferView with ImageData
    *
    * @returns {String}
    */
   var arrayBufferToBinaryString = (jsPDFAPI.__addimage__.arrayBufferToBinaryString = function(
     buffer
   ) {
-    try {
-      return atob(btoa(String.fromCharCode.apply(null, buffer)));
-    } catch (e) {
-      if (
-        typeof Uint8Array !== "undefined" &&
-        typeof Uint8Array.prototype.reduce !== "undefined"
-      ) {
-        return new Uint8Array(buffer)
-          .reduce(function(data, byte) {
-            return data.push(String.fromCharCode(byte)), data;
-          }, [])
-          .join("");
-      }
+    var out = "";
+    // There are calls with both ArrayBuffer and already converted Uint8Array or other BufferView.
+    // Do not copy the array if input is already an array.
+    var buf = isArrayBufferView(buffer) ? buffer : new Uint8Array(buffer);
+    for (var i = 0; i < buf.length; i += ARRAY_APPLY_BATCH) {
+      // Limit the amount of characters being parsed to prevent overflow.
+      // Note that while TextDecoder would be faster, it does not have the same
+      // functionality as fromCharCode with any provided encodings as of 3/2021.
+      out += String.fromCharCode.apply(
+        null,
+        buf.subarray(i, i + ARRAY_APPLY_BATCH)
+      );
     }
+    return out;
   });
 
   /**