Move the string32 helper to the src/display/font_loader.js file

After the previous patches the `string32` helper function is now only used in the `FontLoader.prototype._prepareFontLoadEvent` method, which is stubbed out in the Firefox PDF Viewer, hence move it there instead to avoid bundling dead code.

src/display/font_loader.js

@@ -18,7 +18,6 @@ import {
   FeatureTest,
   isNodeJS,
   shadow,
-  string32,
   unreachable,
   warn,
 } from "../shared/util.js";
@@ -270,6 +269,14 @@ class FontLoader {
         (data.charCodeAt(offset + 3) & 0xff)
       );
     }
+    function string32(value) {
+      return String.fromCharCode(
+        (value >> 24) & 0xff,
+        (value >> 16) & 0xff,
+        (value >> 8) & 0xff,
+        value & 0xff
+      );
+    }
     function spliceString(s, offset, remove, insert) {
       const chunk1 = s.substring(0, offset);
       const chunk2 = s.substring(offset + remove);

src/shared/util.js

@@ -596,21 +596,6 @@ function stringToBytes(str) {
   return bytes;
 }
 
-function string32(value) {
-  if (typeof PDFJSDev === "undefined" || PDFJSDev.test("TESTING")) {
-    assert(
-      typeof value === "number" && Math.abs(value) < 2 ** 32,
-      `string32: Unexpected input "${value}".`
-    );
-  }
-  return String.fromCharCode(
-    (value >> 24) & 0xff,
-    (value >> 16) & 0xff,
-    (value >> 8) & 0xff,
-    value & 0xff
-  );
-}
-
 function objectSize(obj) {
   return Object.keys(obj).length;
 }
@@ -1347,7 +1332,6 @@ export {
   ResponseException,
   setVerbosityLevel,
   shadow,
-  string32,
   stringToBytes,
   stringToPDFString,
   stringToUTF8String,

test/unit/util_spec.js

@@ -19,7 +19,6 @@ import {
   createValidAbsoluteUrl,
   getModificationDate,
   getUuid,
-  string32,
   stringToBytes,
   stringToPDFString,
 } from "../../src/shared/util.js";
@@ -72,14 +71,6 @@ describe("util", function () {
     });
   });
 
-  describe("string32", function () {
-    it("converts unsigned 32-bit integers to strings", function () {
-      expect(string32(0x74727565)).toEqual("true");
-      expect(string32(0x74797031)).toEqual("typ1");
-      expect(string32(0x4f54544f)).toEqual("OTTO");
-    });
-  });
-
   describe("stringToBytes", function () {
     it("handles non-string arguments", function () {
       expect(function () {