Audio file detection by content

3rdparty/taglib/tagutils.cpp

@@ -0,0 +1,105 @@
+/***************************************************************************
+    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;
+}
+
+ByteVector TagLib::Utils::readHeader(IOStream *stream, unsigned int length,
+                                     bool skipID3v2, long *headerOffset)
+{
+  if(!stream || !stream->isOpen())
+    return ByteVector();
+
+  const long originalPosition = stream->tell();
+  long bufferOffset = 0;
+
+  if(skipID3v2) {
+    stream->seek(0);
+    const ByteVector data = stream->readBlock(ID3v2::Header::size());
+    if(data.startsWith(ID3v2::Header::fileIdentifier()))
+      bufferOffset = ID3v2::Header(data).completeTagSize();
+  }
+
+  stream->seek(bufferOffset);
+  const ByteVector header = stream->readBlock(length);
+  stream->seek(originalPosition);
+
+  if(headerOffset)
+    *headerOffset = bufferOffset;
+
+  return header;
+}