/// <summary>Creates the specified header.</summary>
/// <param name="header">The header.</param>
/// <param name="id">The identifier.</param>
/// <param name="flags">The flags.</param>
/// <param name="contentSize">Size of the frame content.</param>
/// <returns></returns>
/// <exception cref="NotSupportedException"></exception>
public static ID3v2FrameHeader Create(ID3v2Header header, string id, ID3v2FrameFlags flags, int contentSize)
{
switch (header.Version)
{
case 2: return(CreateVersion2(header, id, contentSize));
case 3: return(CreateVersion3(header, id, flags, contentSize));
case 4: return(CreateVersion4(header, id, flags, contentSize));
default: throw new NotSupportedException(string.Format("Unsupported ID3v2 Version {0}", header.Version));
}
}
void ParseVersion2(byte[] data)
{
HeaderSize = 6;
ID = ASCII.GetString(data, 0, 3);
Flags = new ID3v2FrameFlags();
var size = 0;
for (var i = 3; i < 6; i++)
{
size = (size << 8) | data[i];
}
ContentSize = size;
}
void ParseVersion3(byte[] data)
{
HeaderSize = 10;
ID = ASCII.GetString(data, 0, 4);
var flags = (ID3v2d3FrameFlags)((data[8] << 8) | data[9]);
Flags = ID3v2FrameFlags.FromID3v2d3(flags);
var size = 0;
for (var i = 4; i < 8; i++)
{
size = (size << 8) | data[i];
}
ContentSize = size;
}
void ParseVersion4(byte[] data)
{
HeaderSize = 10;
ID = ASCII.GetCleanString(data, 0, 4);
var flags = (ID3v2d4FrameFlags)((data[8] << 8) | data[9]);
Flags = ID3v2FrameFlags.FromID3v2d4(flags);
var size = 0;
for (var i = 4; i < 8; i++)
{
if (data[i] > 0x7F)
{
throw new InvalidDataException("ID3v2.4 Header with invalid non-unsynced size value found.");
}
size = (size << 7) | data[i];
}
ContentSize = size;
}
/// <summary>Creates a version3 header.</summary>
/// <param name="header">The header.</param>
/// <param name="id">The identifier.</param>
/// <param name="flags">The flags.</param>
/// <param name="contentSize">Size of the frame content.</param>
/// <returns></returns>
/// <exception cref="ArgumentException">Invalid identifier!.</exception>
/// <exception cref="ArgumentOutOfRangeException"></exception>
public static ID3v2FrameHeader CreateVersion3(ID3v2Header header, string id, ID3v2FrameFlags flags, int contentSize)
{
if (id.Length != 4)
{
throw new ArgumentException("Invalid identifier!", nameof(id));
}
var data = ASCII.GetBytes(id + " ");
var f = (ushort)flags.ToID3v2d3Flags();
data[9] = (byte)(f & 0xFF);
data[8] = (byte)(f >> 8);
for (var i = 7; i >= 4; i--)
{
data[i] = (byte)(contentSize & 0xFF);
contentSize >>= 8;
}
if (contentSize > 0)
{
throw new ArgumentOutOfRangeException(nameof(contentSize));
}
return(new ID3v2FrameHeader(header, data));
}
