////------------------------------------------------------------------------------------------------------------------------------
/// <inheritdoc/>
public IAudioTagOffset ReadFromStream(Stream stream, TagOrigin tagOrigin)
{
if (stream == null)
throw new ArgumentNullException("stream");
if (!stream.CanRead)
throw new InvalidOperationException("stream can not be read");
if (!stream.CanSeek)
throw new InvalidOperationException("stream can not be seeked");
StreamBuffer sb = stream as StreamBuffer ?? new StreamBuffer(stream);
long startOffset = FindIdentifier(sb, tagOrigin);
if (startOffset < 0)
return null;
Id3v1Tag tag = new Id3v1Tag();
string extendedTrackTitle = String.Empty;
string extendedArtist = String.Empty;
string extendAlbumTitle = String.Empty;
if ((startOffset - Id3v1Tag.ExtendedSize) >= 0)
{
sb.Position = startOffset - Id3v1Tag.ExtendedSize;
string extendedHeaderIdentifier = sb.ReadString(ExtendedHeaderIdentifierBytes.Length);
if (String.Equals(extendedHeaderIdentifier, Id3v1Tag.ExtendedHeaderIdentifier, StringComparison.OrdinalIgnoreCase))
{
startOffset = startOffset - ExtendedHeaderIdentifierBytes.Length;
extendedTrackTitle = sb.ReadString(60, _encoding);
extendedArtist = sb.ReadString(60, _encoding);
extendAlbumTitle = sb.ReadString(60, _encoding);
Id3v1TrackSpeed trackSpeed = (Id3v1TrackSpeed)sb.ReadByte();
tag.TrackSpeed = Id3v1Tag.IsValidTrackSpeed(trackSpeed) ? trackSpeed : Id3v1TrackSpeed.Unset;
tag.ExtendedTrackGenre = sb.ReadString(30, _encoding);
tag.StartTime = GetTimeSpan(sb.ReadString(6, _encoding));
tag.EndTime = GetTimeSpan(sb.ReadString(6, _encoding));
tag.UseExtendedTag = true;
}
else
sb.Position = startOffset + HeaderIdentifierBytes.Length;
}
// Read the rest of the tag.
tag.TrackTitle = sb.ReadString(30, _encoding) + extendedTrackTitle;
tag.Artist = sb.ReadString(30, _encoding) + extendedArtist;
tag.AlbumTitle = sb.ReadString(30, _encoding) + extendAlbumTitle;
tag.AlbumYear = sb.ReadString(4);
byte[] comment = new byte[30];
if ((sb.Read(comment, 30) == 30) && (comment[28] == '\0') && (comment[29] != '\0'))
{
tag.TrackNumber = comment[29];
tag.TrackComment = _encoding.GetString(comment, 0, 28);
}
else
tag.TrackComment = _encoding.GetString(comment);
Id3v1Genre genre = (Id3v1Genre)sb.ReadByte();
tag.Genre = Id3v1Tag.IsValidGenre(genre) ? genre : Id3v1Genre.Unknown;
long endOffset = sb.Position;
return new AudioTagOffset(tagOrigin, startOffset, endOffset, tag);
}
/// <summary>
/// Equals the specified <see cref="Id3v1Tag"/>.
/// </summary>
/// <param name="tag">The <see cref="Id3v1Tag"/>.</param>
/// <returns>true if equal; false otherwise.</returns>
public bool Equals(Id3v1Tag tag)
{
if (ReferenceEquals(null, tag))
return false;
if (ReferenceEquals(this, tag))
return true;
return (tag.Version == Version) && (tag.AlbumTitle == AlbumTitle) && (tag.AlbumYear == AlbumYear)
&& (tag.Artist == Artist) && (tag.TrackComment == TrackComment) && (tag.Genre == Genre)
&& (tag.TrackNumber == TrackNumber) && (tag.TrackTitle == TrackTitle)
&& (tag.UseExtendedTag == UseExtendedTag) && (tag.TrackSpeed == TrackSpeed)
&& (tag.ExtendedTrackGenre == ExtendedTrackGenre) && (tag.StartTime == StartTime)
&& (tag.EndTime == EndTime);
}
