Improve the implementation of the PDFDocument.fingerprints-getter

src/core/document.js

@@ -26,6 +26,7 @@ import {
   stringToBytes,
   stringToPDFString,
   stringToUTF8String,
+  toHexUtil,
   unreachable,
   Util,
   warn,
@@ -862,10 +863,6 @@ const STARTXREF_SIGNATURE = new Uint8Array([
 ]);
 const ENDOBJ_SIGNATURE = new Uint8Array([0x65, 0x6e, 0x64, 0x6f, 0x62, 0x6a]);
 
-const FINGERPRINT_FIRST_BYTES = 1024;
-const EMPTY_FINGERPRINT =
-  "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00";
-
 function find(stream, signature, limit = 1024, backwards = false) {
   if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
     assert(limit > 0, 'The "limit" must be a positive integer.');
@@ -1548,30 +1545,24 @@ class PDFDocument {
   }
 
   get fingerprints() {
+    const FINGERPRINT_FIRST_BYTES = 1024;
+    const EMPTY_FINGERPRINT = "\x00".repeat(16);
+
     function validate(data) {
       return (
         typeof data === "string" &&
-        data.length > 0 &&
+        data.length === 16 &&
         data !== EMPTY_FINGERPRINT
       );
     }
 
-    function hexString(hash) {
-      const buf = [];
-      for (const num of hash) {
-        const hex = num.toString(16);
-        buf.push(hex.padStart(2, "0"));
-      }
-      return buf.join("");
-    }
-
-    const idArray = this.xref.trailer.get("ID");
+    const id = this.xref.trailer.get("ID");
     let hashOriginal, hashModified;
-    if (Array.isArray(idArray) && validate(idArray[0])) {
-      hashOriginal = stringToBytes(idArray[0]);
+    if (Array.isArray(id) && validate(id[0])) {
+      hashOriginal = stringToBytes(id[0]);
 
-      if (idArray[1] !== idArray[0] && validate(idArray[1])) {
-        hashModified = stringToBytes(idArray[1]);
+      if (id[1] !== id[0] && validate(id[1])) {
+        hashModified = stringToBytes(id[1]);
       }
     } else {
       hashOriginal = calculateMD5(
@@ -1582,8 +1573,8 @@ class PDFDocument {
     }
 
     return shadow(this, "fingerprints", [
-      hexString(hashOriginal),
-      hashModified ? hexString(hashModified) : null,
+      toHexUtil(hashOriginal),
+      hashModified ? toHexUtil(hashModified) : null,
     ]);
   }
 

src/core/xfa/template.js

@@ -90,6 +90,7 @@ import {
   XFAObject,
   XFAObjectArray,
 } from "./xfa_object.js";
+import { fromBase64Util, Util, warn } from "../../shared/util.js";
 import {
   getBBox,
   getColor,
@@ -102,7 +103,6 @@ import {
   getStringOption,
   HTMLResult,
 } from "./utils.js";
-import { stringToBytes, Util, warn } from "../../shared/util.js";
 import { getMetrics } from "./fonts.js";
 import { recoverJsURL } from "../core_utils.js";
 import { searchNode } from "./som.js";
@@ -3427,7 +3427,7 @@ class Image extends StringObject {
     }
 
     if (!buffer && this.transferEncoding === "base64") {
-      buffer = stringToBytes(atob(this[$content]));
+      buffer = fromBase64Util(this[$content]);
     }
 
     if (!buffer) {

src/display/font_loader.js

@@ -15,11 +15,11 @@
 
 import {
   assert,
-  bytesToString,
   FontRenderOps,
   isNodeJS,
   shadow,
   string32,
+  toBase64Util,
   unreachable,
   warn,
 } from "../shared/util.js";
@@ -399,9 +399,8 @@ class FontFaceObject {
     if (!this.data || this.disableFontFace) {
       return null;
     }
-    const data = bytesToString(this.data);
     // Add the @font-face rule to the document.
-    const url = `url(data:${this.mimetype};base64,${btoa(data)});`;
+    const url = `url(data:${this.mimetype};base64,${toBase64Util(this.data)});`;
     let rule;
     if (!this.cssFontInfo) {
       rule = `@font-face {font-family:"${this.loadedName}";src:${url}}`;

src/shared/util.js

@@ -1097,6 +1097,35 @@ const FontRenderOps = {
   TRANSLATE: 8,
 };
 
+// TODO: Remove this once `Uint8Array.prototype.toHex` is generally available.
+function toHexUtil(arr) {
+  if (Uint8Array.prototype.toHex) {
+    return arr.toHex();
+  }
+  const buf = [];
+  for (const num of arr) {
+    buf.push(num.toString(16).padStart(2, "0"));
+  }
+  return buf.join("");
+}
+
+// TODO: Remove this once `Uint8Array.prototype.toBase64` is generally
+//       available.
+function toBase64Util(arr) {
+  if (Uint8Array.prototype.toBase64) {
+    return arr.toBase64();
+  }
+  return btoa(bytesToString(arr));
+}
+
+// TODO: Remove this once `Uint8Array.fromBase64` is generally available.
+function fromBase64Util(str) {
+  if (Uint8Array.fromBase64) {
+    return Uint8Array.fromBase64(str);
+  }
+  return stringToBytes(atob(str));
+}
+
 export {
   AbortException,
   AnnotationActionEventType,
@@ -1120,6 +1149,7 @@ export {
   FONT_IDENTITY_MATRIX,
   FontRenderOps,
   FormatError,
+  fromBase64Util,
   getModificationDate,
   getUuid,
   getVerbosityLevel,
@@ -1149,6 +1179,8 @@ export {
   stringToPDFString,
   stringToUTF8String,
   TextRenderingMode,
+  toBase64Util,
+  toHexUtil,
   UnexpectedResponseException,
   UnknownErrorException,
   unreachable,