From fa17b4da6b74624ab7451a92353c886e97c4482b Mon Sep 17 00:00:00 2001
From: Tsuda Kageyu <tsuda.kageyu@gmail.com>
Date: Thu, 18 Jun 2015 19:27:21 +0900
Subject: [PATCH 1/3] Avoid overwriting the audio stream when adding an ID3v1
 tag to a FLAC file.

---
 taglib/flac/flacfile.cpp | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/taglib/flac/flacfile.cpp b/taglib/flac/flacfile.cpp
index dbf0d767..4d2d69e6 100644
--- a/taglib/flac/flacfile.cpp
+++ b/taglib/flac/flacfile.cpp
@@ -258,8 +258,16 @@ bool FLAC::File::save()
   }
 
   if(ID3v1Tag()) {
-    seek(-128, End);
+    if(d->hasID3v1) {
+      seek(d->ID3v1Location);
+    }
+    else {
+      seek(0, End);
+      d->ID3v1Location = tell();
+    }
+
     writeBlock(ID3v1Tag()->render());
+    d->hasID3v1 = true;
   }
 
   return true;

From 8fa86162c7c0bd0d9d89d6393225ad7e27d32428 Mon Sep 17 00:00:00 2001
From: Tsuda Kageyu <tsuda.kageyu@gmail.com>
Date: Fri, 19 Jun 2015 09:25:36 +0900
Subject: [PATCH 2/3] Add a test to check if the FLAC audio stream remains
 intact after adding an ID3v1 tag.

---
 tests/test_flac.cpp | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/tests/test_flac.cpp b/tests/test_flac.cpp
index dd09b3ea..54104cc5 100644
--- a/tests/test_flac.cpp
+++ b/tests/test_flac.cpp
@@ -6,6 +6,7 @@
 #include <tpropertymap.h>
 #include <flacfile.h>
 #include <xiphcomment.h>
+#include <id3v1tag.h>
 #include <cppunit/extensions/HelperMacros.h>
 #include "utils.h"
 
@@ -27,6 +28,7 @@ class TestFLAC : public CppUnit::TestFixture
   CPPUNIT_TEST(testInvalid);
   CPPUNIT_TEST(testAudioProperties);
   CPPUNIT_TEST(testZeroSizedPadding);
+  CPPUNIT_TEST(testSaveID3v1);
   CPPUNIT_TEST_SUITE_END();
 
 public:
@@ -283,6 +285,29 @@ public:
     CPPUNIT_ASSERT(f.isValid());
   }
 
+  void testSaveID3v1()
+  {
+    ScopedFileCopy copy("no-tags", ".flac");
+
+    ByteVector audioStream;
+    {
+      FLAC::File f(copy.fileName().c_str());
+      CPPUNIT_ASSERT(!f.hasID3v1Tag());
+      CPPUNIT_ASSERT_EQUAL((long)4692, f.length());
+
+      f.seek(0x0100);
+      audioStream = f.readBlock(4436);
+
+      f.ID3v1Tag(true)->setTitle("01234 56789 ABCDE FGHIJ");
+      f.save();
+      CPPUNIT_ASSERT(f.hasID3v1Tag());
+      CPPUNIT_ASSERT_EQUAL((long)4820, f.length());
+
+      f.seek(0x0100);
+      CPPUNIT_ASSERT_EQUAL(audioStream, f.readBlock(4436));
+    }
+  }
+
 };
 
 CPPUNIT_TEST_SUITE_REGISTRATION(TestFLAC);

From ac5ef0291c87902b57aa6407d8ee4e7c0116badb Mon Sep 17 00:00:00 2001
From: Tsuda Kageyu <tsuda.kageyu@gmail.com>
Date: Mon, 3 Aug 2015 15:51:50 +0900
Subject: [PATCH 3/3] Update NEWS. Fixed possible file corruptions when adding
 an ID3v1 tag to FLAC files.

---
 NEWS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/NEWS b/NEWS
index 61aa6cfe..3d16bd81 100644
--- a/NEWS
+++ b/NEWS
@@ -36,6 +36,7 @@ TagLib 1.10 (??? ??, 2015)
  * New API for the audio length in milliseconds.
  * Marked FLAC::File::streamInfoData() deprecated. It returns an empty ByteVector.
  * Marked FLAC::File::streamLength() deprecated. It returns zero.
+ * Fixed possible file corruptions when adding an ID3v1 tag to FLAC files.
  * Many smaller bug fixes and performance improvements.
 
 TagLib 1.9.1 (Oct 8, 2013)