////------------------------------------------------------------------------------------------------------------------------------
/// <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");
// This tag can only be located at the end; the header does not contain a size field, so we're not able to calculate the end.
if (tagOrigin == TagOrigin.Start)
return null;
StreamBuffer sb = stream as StreamBuffer ?? new StreamBuffer(stream);
Lyrics3Tag tag = new Lyrics3Tag { Encoding = Encoding };
long footerOffset = FindFooterIdentifier(sb);
if (footerOffset < 0)
return null;
sb.Position = Math.Max(footerOffset - Lyrics3Tag.MaxLyricsSize, 0);
long headerOffset = FindHeaderIdentifier(sb);
if (headerOffset < 0)
return null;
// Read lyrics
int lyricsLength = (int)(footerOffset - (headerOffset + HeaderIdentifierBytes.Length));
string lyrics = sb.ReadString(lyricsLength);
tag.Lyrics = GetLyrics(lyrics);
// Read footer
sb.ReadString(FooterIdentifierBytes.Length);
return new AudioTagOffset(tagOrigin, headerOffset, footerOffset, tag);
}
/// <summary>
/// Equals the specified <see cref="Lyrics3Tag"/>.
/// </summary>
/// <param name="tag">The <see cref="Lyrics3Tag"/>.</param>
/// <returns>true if equal; false otherwise.</returns>
public bool Equals(Lyrics3Tag tag)
{
if (ReferenceEquals(null, tag))
return false;
if (ReferenceEquals(this, tag))
return true;
return String.Equals(tag.Lyrics, Lyrics, StringComparison.OrdinalIgnoreCase);
}