/// <summary>
/// Loads ID3v2ExtendedHeaderFlags from the specified ID3v2.4 extended header.
/// </summary>
/// <param name="extendedHeader"></param>
/// <returns></returns>
public static ID3v2ExtendedHeaderFlags FromID3v24(byte[] extendedHeader)
{
if (extendedHeader == null)
{
throw new ArgumentNullException("ExtendedHeader");
}
if (extendedHeader[4] != 1)
{
throw new InvalidDataException(string.Format("Invalid number of flag bytes!"));
}
var i = 6;
// flag 1000 0000
if ((extendedHeader[5] & 0x80) != 0)
{
SkipFlag(extendedHeader, ref i);
}
// flag 0100 0000
var l_TagIsUpdate = (extendedHeader[5] & 0x40) != 0;
if (l_TagIsUpdate)
{
SkipFlag(extendedHeader, ref i);
}
// flag 0010 0000
byte[] cRC32;
if ((extendedHeader[5] & 0x20) != 0)
{
cRC32 = ReadCRC32(extendedHeader, ref i);
}
else
{
cRC32 = null;
}
// flag 0001 0000
ID3v2ExtendedHeaderRestrictions l_TagRestrictions;
if ((extendedHeader[5] & 0x10) == 0)
{
l_TagRestrictions = null;
}
else
{
var bytes = ReadFlag(extendedHeader, ref i);
if (bytes.Length != 1)
{
throw new InvalidDataException(string.Format("Invalid data length"));
}
l_TagRestrictions = ID3v2ExtendedHeaderRestrictions.FromID3v24(bytes[0]);
}
// read unknown flags (0000 xxxx)
for (var n = 0x08; n != 0; n >>= 1)
{
SkipFlag(extendedHeader, ref i);
}
if (i != extendedHeader.Length)
{
throw new InvalidDataException(string.Format("Unexpected additional data at flag!"));
}
return(new ID3v2ExtendedHeaderFlags(l_TagIsUpdate, cRC32, l_TagRestrictions));
}
/// <summary>
/// Creates new ID3v2ExtendedHeaderFlags with the specified settings.
/// </summary>
/// <param name="tagIsUpdate"></param>
/// <param name="cRC32">The crc32 of all frames (tag without headers, padding and footer).</param>
/// <param name="tagRestrictions"></param>
public ID3v2ExtendedHeaderFlags(bool tagIsUpdate, byte[] cRC32, ID3v2ExtendedHeaderRestrictions tagRestrictions)
{
TagIsUpdate = tagIsUpdate;
CRC32 = cRC32;
TagRestrictions = tagRestrictions;
}