Unify common functions for finding tags.

Several classes have exactly identical functions for finding tags.
This also hides the functions from public headers.

1 files changed, 79 insertions, 0 deletions

diff --git a/taglib/tagutils.cpp b/taglib/tagutils.cpp
new file mode 100644
index 00000000..dc047040
--- /dev/null
+++ b/taglib/tagutils.cpp
@@ -0,0 +1,79 @@
+/***************************************************************************
+    copyright            : (C) 2015 by Tsuda Kageyu
+    email                : tsuda.kageyu@gmail.com
+ ***************************************************************************/
+
+/***************************************************************************
+ *   This library is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU Lesser General Public License version   *
+ *   2.1 as published by the Free Software Foundation.                     *
+ *                                                                         *
+ *   This library is distributed in the hope that it will be useful, but   *
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of            *
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU     *
+ *   Lesser General Public License for more details.                       *
+ *                                                                         *
+ *   You should have received a copy of the GNU Lesser General Public      *
+ *   License along with this library; if not, write to the Free Software   *
+ *   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA         *
+ *   02110-1301  USA                                                       *
+ *                                                                         *
+ *   Alternatively, this file is available under the Mozilla Public        *
+ *   License Version 1.1.  You may obtain a copy of the License at         *
+ *   http://www.mozilla.org/MPL/                                           *
+ ***************************************************************************/
+
+#include <tfile.h>
+
+#include "id3v1tag.h"
+#include "id3v2header.h"
+#include "apetag.h"
+
+#include "tagutils.h"
+
+using namespace TagLib;
+
+long Utils::findID3v1(File *file)
+{
+  if(!file->isValid())
+    return -1;
+
+  file->seek(-128, File::End);
+  const long p = file->tell();
+
+  if(file->readBlock(3) == ID3v1::Tag::fileIdentifier())
+    return p;
+
+  return -1;
+}
+
+long Utils::findID3v2(File *file)
+{
+  if(!file->isValid())
+    return -1;
+
+  file->seek(0);
+
+  if(file->readBlock(3) == ID3v2::Header::fileIdentifier())
+    return 0;
+
+  return -1;
+}
+
+long Utils::findAPE(File *file, long id3v1Location)
+{
+  if(!file->isValid())
+    return -1;
+
+  if(id3v1Location >= 0)
+    file->seek(id3v1Location - 32, File::Beginning);
+  else
+    file->seek(-32, File::End);
+
+  const long p = file->tell();
+
+  if(file->readBlock(8) == APE::Tag::fileIdentifier())
+    return p;
+
+  return -1;
+}