/// <summary>
/// Reads an ID3v2 tag from a stream. Returns null if no ID3v2 tag can be found
/// in the stream.
/// </summary>
/// <param name="stream">The stream to read.</param>
/// <returns>The tag read from the stream, or null if no ID3v2 tag can be found.</returns>
public static ID3v2Tag ReadTag(Stream stream)
{
ID3Versions version = LookForTag(stream);
ID3v2Tag tag = null;
if ((version & ID3Versions.V2) == ID3Versions.V2)
{
tag = new ID3v2Tag();
tag.headerFlags = ReadFlags(stream, version);
int tagSize = ReadTagSize(stream);
// Go to the first byte after the header
stream.Seek(TAG_HEADER_LENGTH, SeekOrigin.Begin);
while (stream.Position < tagSize)
{
ID3v2Frame newFrame = ID3v2Frame.ReadFrame(stream, version);
if (newFrame != null)
{
tag.AddFrame(newFrame);
}
else
{
break;
}
}
}
return(tag);
}
/// <summary>
/// Copy constructor.
/// </summary>
/// <param name="tag">The tag to copy.</param>
public ID3v2Tag(ID3Tag tag)
: base(tag)
{
ID3v2Tag v2Tag = tag as ID3v2Tag;
if (v2Tag != null)
{
this.paddingSize = v2Tag.paddingSize;
this.headerFlags = v2Tag.headerFlags;
this.frames = new Dictionary <FrameType, ID3v2Frame>(v2Tag.FrameCount);
foreach (ID3v2Frame frame in v2Tag.Frames)
{
this.AddFrame(frame.Copy());
}
}
}
/// <summary>
/// Examines the stream to see if there is sufficient space for the tag to be written.
/// If there is not enough space, sufficient space is made.
/// </summary>
/// <param name="stream">The stream to check for space.</param>
/// <param name="writeVersion">The version to use in calculating space required.</param>
private void EnsureSpace(Stream stream, ID3Versions writeVersion)
{
ID3Versions existingTagVersion = ID3v2Tag.LookForTag(stream);
if ((existingTagVersion & ID3Versions.V2) == ID3Versions.V2)
{
int existingSize = ReadTagSize(stream);
if (existingSize < this.GetTotalSize(writeVersion))
{
SmartPadding(stream, existingSize, writeVersion);
}
else
{
this.PaddingSize += existingSize - this.GetTotalSize(writeVersion);
}
}
else
{
SmartPadding(stream, 0, writeVersion);
}
}
/// <summary>
/// Removes any ID3v2 tag from a stream.
/// </summary>
/// <param name="stream">The stream whose ID3v2 tag will be removed.</param>
public static void RemoveTag(Stream stream)
{
ID3Versions version = ID3v2Tag.LookForTag(stream);
if ((version & ID3Versions.V2) == ID3Versions.V2)
{
int tagSize = ReadTagSize(stream);
long newSize = stream.Length - tagSize;
int bufLength;
long startPosition;
byte[] buffer;
stream.Seek(tagSize, SeekOrigin.Begin);
while (stream.Position < stream.Length)
{
bufLength = 10000;
if (stream.Position + bufLength > stream.Length)
{
bufLength = (int)(stream.Length - stream.Position);
}
buffer = new byte[bufLength];
stream.Read(buffer, 0, bufLength);
startPosition = stream.Position;
stream.Position = startPosition - (tagSize + bufLength);
stream.Write(buffer, 0, bufLength);
stream.Position = startPosition;
}
stream.Flush();
stream.SetLength(newSize);
}
else
{
throw new TagNotFoundException("No tag found");
}
}
