bool ParseVersion3(DataFrameReader reader)
{
if (!reader.EnsureBuffer(4))
{
return false;
}
// calc size
byte[] sizeBytes = reader.Read(0, 4);
int size = 0;
for (int i = 0; i < 4; i++)
{
size = (size << 8) | sizeBytes[i];
}
size += 4;
// get data
if (!reader.EnsureBuffer(size))
{
return false;
}
m_Data = reader.GetBuffer(size);
// get flags
m_Flags = ID3v2ExtendedHeaderFlags.FromID3v23(m_Data);
return true;
}
bool ParseVersion4(DataFrameReader reader)
{
if (!reader.EnsureBuffer(4))
{
return false;
}
// calc size
int size = ID3v2DeUnsync.Int32(reader.Read(0, 4), 0);
// get data
if (!reader.EnsureBuffer(size))
{
return false;
}
m_Data = reader.GetBuffer(size);
// get flags
m_Flags = ID3v2ExtendedHeaderFlags.FromID3v24(m_Data);
return true;
}
/// <summary>
/// Parses the specified buffer starting at index to load all data for this frame.
/// </summary>
/// <param name="reader">FrameReader to read from.</param>
public override bool Parse(DataFrameReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("Reader");
}
if (!reader.EnsureBuffer(10))
{
return(false);
}
m_Data = reader.Read(0, 10);
ParseData();
return(true);
}
/// <summary>
/// uses the <see cref="Search"/> class to find the next id3 / mp3 frame start at the buffer.
/// </summary>
/// <returns>Returns the search result.</returns>
Search FindFrame()
{
// initialize the search and run it at the buffer
var search = new Search();
while (true)
{
// fill the buffer
if (!m_Reader.EnsureBuffer(1024) && (m_Reader.Available < 4))
{
if (m_Reader.Available == 0)
{
return(null);
}
// end of stream
var buffer = m_Reader.GetBuffer(m_Reader.Available);
InvalidData(buffer);
return(null);
}
// run the search
{
if (m_Reader.Contains(search))
{
return(search);
}
// nothing found, enqueue invalid data...
var buffer = m_Reader.GetBuffer(m_Reader.Available - 2);
InvalidData(buffer);
// .. and start new search
search = new Search();
}
}
}
/// <summary>
/// Parses the specified stream to load all fields for this instance.
/// </summary>
/// <param name="reader">FrameReader to read from.</param>
public override bool Parse(DataFrameReader reader)
{
if (reader == null)
{
throw new ArgumentNullException("Reader");
}
if (!reader.EnsureBuffer(4))
{
return(false);
}
var headerData = reader.Read(0, 4);
Header = new MP3AudioFrameHeader(headerData);
if (Header.Validation != MP3AudioFrameHeadervalidation.Valid)
{
return(false);
}
var dataLength = Header.Length;
if (dataLength == 0)
{
return(false);
}
if (!reader.EnsureBuffer(dataLength))
{
return(false);
}
m_Data = reader.Read(0, dataLength);
// check next header
if (reader.EnsureBuffer(dataLength + 4))
{
var nextHeaderBuffer = reader.Read(dataLength, 4);
var next = new MP3AudioFrameHeader(nextHeaderBuffer);
if (next.Validation != MP3AudioFrameHeadervalidation.Valid)
{
if ((nextHeaderBuffer[0] == 'I') && (nextHeaderBuffer[1] == 'D') && (nextHeaderBuffer[2] == '3'))
{
// ID3 v2 tag incoming
}
else if ((nextHeaderBuffer[0] == 'T') && (nextHeaderBuffer[1] == 'A') && (nextHeaderBuffer[2] == 'G'))
{
// ID3 v1 tag incoming
}
else
{
// next header is invalid, check if the padding bit is set incorrectly
// there is a high pobability that the padding bit is invalid if
// the framestart is not directly after our buffer but one byte late
var newStart = dataLength + (Header.Padding ? -1 : 1);
nextHeaderBuffer = reader.Read(newStart, 4);
next = new MP3AudioFrameHeader(nextHeaderBuffer);
if (next.Validation == MP3AudioFrameHeadervalidation.Valid)
{
if (!Header.Padding)
{
// frame has a padding byte but the header padding bit is not set
m_Data = reader.Read(0, newStart);
}
else
{
// frame has no padding byte but the header padding bit is set
m_Data = reader.Read(0, newStart);
}
InvalidPaddingCorrected = true;
}
}
}
}
reader.Remove(m_Data.Length);
return(true);
}
