Decode unsynch-encoded tag (ID3v2.3) and frame (ID3v2.4) data before parsing them.

BUG:138829


git-svn-id: svn://anonsvn.kde.org/home/kde/trunk/kdesupport/taglib@733565 283d02a7-25f6-0310-bc7c-ecb5cbfe19da

taglib/mpeg/id3v2/id3v2framefactory.cpp

@@ -28,6 +28,7 @@
 #include <tdebug.h>
 
 #include "id3v2framefactory.h"
+#include "id3v2synchdata.h"
 
 #include "frames/attachedpictureframe.h"
 #include "frames/commentsframe.h"
@@ -71,6 +72,15 @@ Frame *FrameFactory::createFrame(const ByteVector &data, bool synchSafeInts) con
 
 Frame *FrameFactory::createFrame(const ByteVector &data, uint version) const
 {
+  Header tagHeader;
+  tagHeader.setMajorVersion(version);
+  return createFrame(data, &tagHeader);
+}
+
+Frame *FrameFactory::createFrame(const ByteVector &origData, Header *tagHeader) const
+{
+  ByteVector data = origData;
+  uint version = tagHeader->majorVersion();
   Frame::Header *header = new Frame::Header(data, version);
   ByteVector frameID = header->frameID();
 
@@ -78,7 +88,7 @@ Frame *FrameFactory::createFrame(const ByteVector &data, uint version) const
   // characters.  Also make sure that there is data in the frame.
 
   if(!frameID.size() == (version < 3 ? 3 : 4) ||
-     header->frameSize() <= 0 ||
+     header->frameSize() <= (header->dataLengthIndicator() ? 4 : 0) ||
      header->frameSize() > data.size())
   {
     delete header;
@@ -92,6 +102,14 @@ Frame *FrameFactory::createFrame(const ByteVector &data, uint version) const
     }
   }
 
+  if(version > 3 && (tagHeader->unsynchronisation() || header->unsynchronisation())) {
+    // Data lengths are not part of the encoded data, but since they are synch-safe
+    // integers they will be never actually encoded.
+    ByteVector frameData = data.mid(Frame::Header::size(version), header->frameSize());
+    SynchData::decode(frameData);
+    data = data.mid(0, Frame::Header::size(version)) + frameData;
+  }
+
   // TagLib doesn't mess with encrypted frames, so just treat them
   // as unknown frames.
 

taglib/mpeg/id3v2/id3v2framefactory.h

@@ -29,6 +29,7 @@
 #include "taglib_export.h"
 #include "tbytevector.h"
 #include "id3v2frame.h"
+#include "id3v2header.h"
 
 namespace TagLib {
 
@@ -64,8 +65,8 @@ namespace TagLib {
        * false if we are parsing an old tag (v2.3 or older) that does not support
        * synchsafe ints.
        *
-       * \deprecated Please use the method below that accepts an ID3 version
-       * number in new code.
+       * \deprecated Please use the method below that accepts a ID3v2::Header
+       * instance in new code.
        */
       Frame *createFrame(const ByteVector &data, bool synchSafeInts) const;
 
@@ -73,9 +74,18 @@ namespace TagLib {
        * Create a frame based on \a data.  \a version should indicate the ID3v2
        * version of the tag.  As ID3v2.4 is the most current version of the
        * standard 4 is the default.
+       *
+       * \deprecated Please use the method below that accepts a ID3v2::Header
+       * instance in new code.
+       */
+      Frame *createFrame(const ByteVector &data, uint version = 4) const;
+
+      /*!
+       * Create a frame based on \a data.  \a tagHeader should be a valid
+       * ID3v2::Header instance.
        */
       // BIC: make virtual
-      Frame *createFrame(const ByteVector &data, uint version = 4) const;
+      Frame *createFrame(const ByteVector &data, Header *tagHeader) const;
 
       /*!
        * Returns the default text encoding for text frames.  If setTextEncoding()

taglib/mpeg/id3v2/id3v2header.cpp

@@ -101,6 +101,11 @@ TagLib::uint Header::majorVersion() const
   return d->majorVersion;
 }
 
+void Header::setMajorVersion(TagLib::uint version)
+{
+  d->majorVersion = version;
+}
+
 TagLib::uint Header::revisionNumber() const
 {
   return d->revisionNumber;

taglib/mpeg/id3v2/id3v2header.h

@@ -69,6 +69,13 @@ namespace TagLib {
        */
       uint majorVersion() const;
 
+      /*!
+       * Set the the major version number to \a version.  (Note: This is
+       * the 4, not the 2 in ID3v2.4.0.  The 2 is implied.)
+       * \see majorVersion()
+       */
+      void setMajorVersion(uint version);
+
       /*!
        * Returns the revision number.  (Note: This is the 0, not the 4 in
        * ID3v2.4.0.  The 2 is implied.)

taglib/mpeg/id3v2/id3v2synchdata.cpp

@@ -50,3 +50,23 @@ ByteVector SynchData::fromUInt(uint value)
 
   return v;
 }
+
+void SynchData::decode(ByteVector &data)
+{
+  char *n = data.data();
+  const char *o = data.data();
+  const char *end = o + data.size();
+
+  if(data.size() <= 0)
+    return;
+
+  while(o < end - 1) {
+    *n++ = *o;
+    if(o[0] == '\xFF' && o[1] == '\x00')
+      o++;
+    o++;
+  }
+  *n++ = *o;
+
+  data.resize(n - data.data());
+}

taglib/mpeg/id3v2/id3v2synchdata.h

@@ -57,6 +57,11 @@ namespace TagLib {
        * Returns a 4 byte (32 bit) synchsafe integer based on \a value.
        */
       ByteVector fromUInt(uint value);
+
+      /*!
+       * Deunsynchronize the data (in-place).
+       */
+      void decode(ByteVector &data);
     }
 
   }

taglib/mpeg/id3v2/id3v2tag.cpp

@@ -30,6 +30,7 @@
 #include "id3v2header.h"
 #include "id3v2extendedheader.h"
 #include "id3v2footer.h"
+#include "id3v2synchdata.h"
 
 #include "id3v1genres.h"
 
@@ -381,8 +382,14 @@ void ID3v2::Tag::read()
   }
 }
 
-void ID3v2::Tag::parse(const ByteVector &data)
+void ID3v2::Tag::parse(const ByteVector &origData)
 {
+  ByteVector data = origData;
+
+  if(d->header.unsynchronisation() && d->header.majorVersion() <= 3) {
+    SynchData::decode(data);
+  }
+
   uint frameDataPosition = 0;
   uint frameDataLength = data.size();
 
@@ -424,7 +431,7 @@ void ID3v2::Tag::parse(const ByteVector &data)
     }
 
     Frame *frame = d->factory->createFrame(data.mid(frameDataPosition),
-                                           d->header.majorVersion());
+                                           &d->header);
 
     if(!frame)
       return;