From 80342e2fdc36fc5d08c663f87c40e378417c4826 Mon Sep 17 00:00:00 2001
From: Jonas Jenwald <jonas.jenwald@gmail.com>
Date: Tue, 5 Nov 2019 11:52:30 +0100
Subject: [PATCH] Support UTF-16 little-endian strings in the
 `stringToPDFString` helper function (bug 1593902)

The bug report seem to suggest that we don't support UTF-16 strings with a BOM (byte order mark), which we *actually* do as evident by both the code and a unit-test.
The issue at play here is rather that we previously only supported big-endian UTF-16 BOM, and the `Title` string in the PDF document is using a *little-endian* UTF-16 BOM instead.

Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1593902
---
 src/shared/util.js     |  6 ++++++
 test/unit/util_spec.js | 11 ++++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/src/shared/util.js b/src/shared/util.js
index 589bb4887..62c53a577 100644
--- a/src/shared/util.js
+++ b/src/shared/util.js
@@ -752,6 +752,12 @@ function stringToPDFString(str) {
       strBuf.push(String.fromCharCode(
         (str.charCodeAt(i) << 8) | str.charCodeAt(i + 1)));
     }
+  } else if (str[0] === '\xFF' && str[1] === '\xFE') {
+    // UTF16LE BOM
+    for (let i = 2; i < length; i += 2) {
+      strBuf.push(String.fromCharCode(
+        (str.charCodeAt(i + 1) << 8) | str.charCodeAt(i)));
+    }
   } else {
     for (let i = 0; i < length; ++i) {
       const code = PDFStringTranslateTable[str.charCodeAt(i)];
diff --git a/test/unit/util_spec.js b/test/unit/util_spec.js
index cd2c9724d..ce1f0c21e 100644
--- a/test/unit/util_spec.js
+++ b/test/unit/util_spec.js
@@ -179,11 +179,16 @@ describe('util', function() {
       expect(stringToPDFString(str)).toEqual('\u201Cstring\u201D');
     });
 
-    it('handles UTF-16BE strings', function() {
+    it('handles UTF-16 big-endian strings', function() {
       let str = '\xFE\xFF\x00\x73\x00\x74\x00\x72\x00\x69\x00\x6E\x00\x67';
       expect(stringToPDFString(str)).toEqual('string');
     });
 
+    it('handles UTF-16 little-endian strings', function() {
+      let str = '\xFF\xFE\x73\x00\x74\x00\x72\x00\x69\x00\x6E\x00\x67\x00';
+      expect(stringToPDFString(str)).toEqual('string');
+    });
+
     it('handles empty strings', function() {
       // ISO Latin 1
       let str1 = '';
@@ -192,6 +197,10 @@ describe('util', function() {
       // UTF-16BE
       let str2 = '\xFE\xFF';
       expect(stringToPDFString(str2)).toEqual('');
+
+      // UTF-16LE
+      let str3 = '\xFF\xFE';
+      expect(stringToPDFString(str3)).toEqual('');
     });
   });