private bool ReadFieldInstance(StreamBuffer sb, long maximumFieldSize)
{
if (sb == null)
throw new ArgumentNullException("sb");
string identifier = sb.ReadString(FieldIdentifierLength);
string strFieldSize = sb.ReadString(FieldSizeLength);
int fieldSize;
if (!Int32.TryParse(strFieldSize, out fieldSize))
{
#if DEBUG
return false;//throw new InvalidDataException(String.Format("Size value for field {0} is not an int: {1}", identifier, strFieldSize));
#else
return false;
#endif
}
Identifier = identifier;
_data = new byte[fieldSize];
sb.Read(_data, fieldSize);
if (!IsValidData(_data))
return false;
Data = _data;
return true;
}
/// <summary>
/// Reads a <see cref="MpaFrame"/> from a <see cref="Stream"/>.
/// </summary>
/// <param name="stream">The stream.</param>
/// <returns>
/// true if found; otherwise, null.
/// </returns>
/// <exception cref="System.ArgumentNullException">Thrown if stream is null.</exception>
private bool ReadFrame(StreamBuffer stream)
{
if (stream == null)
throw new ArgumentNullException("stream");
StartOffset = stream.Position;
if (!ParseHeader(stream))
return false;
int frameLength = FrameLength, audioDataLength = 0;
if (frameLength > FrameHeaderSize)
audioDataLength = frameLength - FrameHeaderSize;
if (audioDataLength == 0)
return true;
if ((stream.Length - stream.Position) < audioDataLength)
{
// Truncated audio data.
audioDataLength = (int)(stream.Length - stream.Position);
}
AudioData = new byte[audioDataLength];
int bytesDataRead = stream.Read(AudioData, 0, audioDataLength);
// Read the CRC
// Create a buffer to read the CRC stored after the frame (2 bytes)
if (bytesDataRead >= 2)
{
byte[] crc = new byte[2];
Buffer.BlockCopy(AudioData, 0, crc, 0, 2);
Crc = StreamBuffer.SwitchEndianness(BitConverter.ToInt16(crc, 0));
}
EndOffset = stream.Position;
return true;
}
private static ApeHeader ReadHeader(StreamBuffer stream, long startHeaderPosition, long endHeaderPosition)
{
if (stream == null)
throw new ArgumentNullException("stream");
stream.Position = startHeaderPosition;
while (startHeaderPosition < endHeaderPosition)
{
int y = 0;
while (stream.ReadByte() == TagIdentifierBytes[y++])
{
startHeaderPosition++;
if (y != TagIdentifierBytes.Length)
continue;
ApeHeader hdr = new ApeHeader
{
Position = stream.Position - TagIdentifierBytes.Length,
Version = (ApeVersion)(stream.ReadLittleEndianInt32() / 1000),
Size = stream.ReadLittleEndianInt32(),
FrameCount = stream.ReadLittleEndianInt32(),
Flags = stream.ReadLittleEndianInt32(),
ReservedBytes = new byte[8]
};
stream.Read(hdr.ReservedBytes, 8);
if (IsValidTag(hdr))
return hdr;
startHeaderPosition -= ApeTag.HeaderSize;
stream.Position = startHeaderPosition + 1;
break;
}
startHeaderPosition++;
}
return null;
}
/// <summary>
/// Reads the header.
/// </summary>
/// <param name="sb">The <see cref="StreamBuffer"/>.</param>
/// <returns>
/// true if the header is read and valid; otherwise, false.
/// </returns>
/// <exception cref="System.ArgumentNullException">Thrown if <paramref name="sb"/> is null.</exception>
private bool ReadHeader(StreamBuffer sb)
{
if (sb == null)
throw new ArgumentNullException("sb");
long startPosition = sb.Position;
// Sync code '11111111111110'
_header = sb.ReadBigEndianInt32();
if (((_header >> 18) & FrameSync) != FrameSync)
return false;
/*
Blocking strategy:
•0 : fixed-block size stream; frame header encodes the frame number
•1 : variable-block size stream; frame header encodes the sample number
*/
long num = ReadBigEndianUtf8Int64(sb, out _sampleFrameNumberBytes);
switch (BlockingStrategy)
{
case FlacBlockingStrategy.FixedBlocksize:
Samples = num;
FrameNumber = num
*
(FlacStream.StreamInfoMetadataBlocks.Any()
? FlacStream.StreamInfoMetadataBlocks.First().MinimumBlockSize
: 1);
break;
case FlacBlockingStrategy.VariableBlocksize:
Samples = num;
FrameNumber = -1;
break;
}
/*
Block size in inter-channel samples:
•0000 : reserved
•0001 : 192 samples
•0010-0101 : 576 * (2 ^ (n - 2)) samples, i.e. 576/1152/2304/4608
•0110 : get 8 bit (block size - 1) from end of header
•0111 : get 16 bit (block size - 1) from end of header
•1000-1111 : 256 * (2 ^ (n - 8)) samples, i.e. 256/512/1024/2048/4096/8192/16384/3276
*/
int blockSize = (_header >> 12) & 0xF;
switch (blockSize)
{
case 0x01:
BlockSize = 192;
break;
case 0x02:
case 0x03:
case 0x04:
case 0x05:
BlockSize = 576 << (blockSize - 2);
break;
case 0x06:
BlockSize = sb.ReadByte() + 1;
break;
case 0x07:
BlockSize = sb.ReadBigEndianInt16() + 1;
break;
default:
BlockSize = 256 << (blockSize - 8);
break;
}
/*
Sample rate:
•0000 : get from STREAMINFO metadata block
•0001 : 88.2kHz
•0010 : 176.4kHz
•0011 : 192kHz
•0100 : 8kHz
•0101 : 16kHz
•0110 : 22.05kHz
•0111 : 24kHz
•1000 : 32kHz
•1001 : 44.1kHz
•1010 : 48kHz
•1011 : 96kHz
•1100 : get 8 bit sample rate (in kHz) from end of header
•1101 : get 16 bit sample rate (in Hz) from end of header
•1110 : get 16 bit sample rate (in tens of Hz) from end of header
•1111 : invalid, to prevent sync-fooling string of 1s
*/
int samplingRate = (_header >> 8) & 0xF;
if (samplingRate == 0x00)
{
SamplingRate = FlacStream.StreamInfoMetadataBlocks.Any()
? FlacStream.StreamInfoMetadataBlocks.First().SampleRate
: 0;
}
else if (samplingRate <= 0x0B)
{
SamplingRate = SampleRates[samplingRate];
}
else
{
switch (samplingRate)
{
case 0x0C:
// Sample rate in kHz
SamplingRate = sb.ReadByte() * 1000;
break;
case 0x0D:
// Sample rate in Hz
SamplingRate = sb.ReadBigEndianInt16();
break;
case 0x0E:
// Sample rate in 10s of Hz
SamplingRate = sb.ReadBigEndianInt16() * 10;
break;
}
}
/*
Channel assignment
•0000-0111 : (number of independent channels)-1. Where defined, the channel order follows SMPTE/ITU-R recommendations.
The assignments are as follows:
◦1 channel: mono
◦2 channels: left, right
◦3 channels: left, right, center
◦4 channels: front left, front right, back left, back right
◦5 channels: front left, front right, front center, back/surround left, back/surround right
◦6 channels: front left, front right, front center, LFE, back/surround left, back/surround right
◦7 channels: front left, front right, front center, LFE, back center, side left, side right
◦8 channels: front left, front right, front center, LFE, back left, back right, side left, side right
•1000 : left/side stereo: channel 0 is the left channel, channel 1 is the side(difference) channel
•1001 : right/side stereo: channel 0 is the side(difference) channel, channel 1 is the right channel
•1010 : mid/side stereo: channel 0 is the mid(average) channel, channel 1 is the side(difference) channel
•1011-1111 : reserved
*/
int channelAssignment = (_header >> 4) & 0xF;
if (channelAssignment < 0x08)
{
ChannelAssignment = FlacChannelAssignment.Independent;
Channels = channelAssignment + 1;
}
else
{
Channels = 2;
switch (channelAssignment)
{
case 0x08:
ChannelAssignment = FlacChannelAssignment.LeftSide;
break;
case 0x09:
ChannelAssignment = FlacChannelAssignment.RightSide;
break;
case 0x0A:
ChannelAssignment = FlacChannelAssignment.MidSide;
break;
}
}
/*
Sample size in bits:
•000 : get from STREAMINFO metadata block
•001 : 8 bits per sample
•010 : 12 bits per sample
•011 : reserved
•100 : 16 bits per sample
•101 : 20 bits per sample
•110 : 24 bits per sample
•111 : reserved
*/
int sampleSize = (_header >> 0x01) & 0x07;
SampleSize = (sampleSize == 0x00)
? (FlacStream.StreamInfoMetadataBlocks.Any()
? FlacStream.StreamInfoMetadataBlocks.First().BitsPerSample
: 0)
: SampleSizes[sampleSize];
_crc8 = sb.ReadByte();
long endPosition = sb.Position;
long length = endPosition - startPosition;
byte[] crcBytes = new byte[length];
sb.Position -= length;
sb.Read(crcBytes, (int)length);
byte crc8 = Crc8.Calculate(crcBytes);
if (_crc8 != crc8)
throw new InvalidDataException("Corrupt CRC8.");
return true;
}
////------------------------------------------------------------------------------------------------------------------------------
private static long ReadBigEndianUtf8Int64(StreamBuffer sb, out byte[] utf8Bytes)
{
//// Decoded long range Coded value
//// 0000 0000 ・00 0000 007F 0xxxxxxx
//// 0000 0080 ・00 0000 07FF 110xxxxx 10xxxxxx
//// 0000 0800 ・00 0000 FFFF 1110xxxx 10xxxxxx 10xxxxxx
//// 0001 0000 ・00 001F FFFF 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
//// 0020 0000 ・00 03FF FFFF 111110xx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
//// 0400 0000 ・00 7FFF FFFF 1111110x 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
//// 8000 0000 ・0F FFFF FFFF 11111110 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx 10xxxxxx
// Where xxx represent the bits in the uncoded value, in the same order.
const int ByteCountMask = 0x80; // 10000000
const int ByteMask = 0x3F; // 00111111
int byteCount = 1;
long value = sb.ReadByte();
if (value > ByteCountMask)
{
int bytes = 0;
while (((value << bytes) & ByteCountMask) == ByteCountMask)
bytes++;
value &= ByteMask >> (bytes - 1);
for (int i = bytes - 1; i > 0; i--)
value = (value << (6 * i)) | ((long)sb.ReadByte() & ByteMask);
byteCount += bytes - 1;
}
sb.Position -= byteCount;
utf8Bytes = new byte[byteCount];
sb.Read(utf8Bytes, byteCount);
return value;
}
private static MusicMatchHeader ReadHeaderFooter(StreamBuffer stream, long startHeaderPosition, long endHeaderPosition, IList<byte> identifierBytes, TagOrigin tagOrigin)
{
if (stream == null)
throw new ArgumentNullException("stream");
stream.Position = startHeaderPosition;
while (startHeaderPosition < endHeaderPosition)
{
int y = 0;
while (stream.ReadByte() == identifierBytes[y++])
{
startHeaderPosition++;
if (y != identifierBytes.Count)
continue;
if (tagOrigin == TagOrigin.Start)
{
MusicMatchHeader header = new MusicMatchHeader
{
Position = stream.Position - identifierBytes.Count,
Padding1 = new byte[2],
Padding2 = new byte[2],
Padding3 = new byte[2],
SpacePadding2 = new byte[226]
};
// 0x00 0x00 Padding
stream.Read(header.Padding1, header.Padding1.Length);
// <8-byte numerical ASCII string>
header.XingEncoderVersion = stream.ReadString(8);
// 0x00 0x00 Padding
stream.Read(header.Padding2, header.Padding2.Length);
// Xing encoder version <8-byte numerical ASCII string>
header.MusicMatchVersion = stream.ReadString(8);
// 0x00 0x00 Padding
stream.Read(header.Padding3, header.Padding3.Length);
// Space padding <226 * 0x20 >
stream.Read(header.SpacePadding2, header.SpacePadding2.Length);
ValidateHeader(header, null);
return header;
}
if (tagOrigin == TagOrigin.End)
{
MusicMatchHeader footer = new MusicMatchHeader
{
Position = stream.Position - identifierBytes.Count,
SpacePadding1 = new byte[13],
SpacePadding2 = new byte[12]
};
// Space padding <13 * 0x20>
stream.Read(footer.SpacePadding1, 13);
// version <4-byte numerical ASCII string> e.g. 3.05
footer.MusicMatchVersion = stream.ReadString(4);
// Space padding <12 * 0x20>
stream.Read(footer.SpacePadding2, 12);
ValidateHeader(null, footer);
return footer;
}
}
startHeaderPosition++;
}
return null;
}
private bool ReadItem(ApeVersion version, int valueSize, StreamBuffer stream, long maximumItemSize)
{
if (stream == null)
throw new ArgumentNullException("stream");
// Check if the item size indicated is really the size of the item.
// Some files just aren't... properly written.
byte[] data = new byte[valueSize];
int dataBytesRead = stream.Read(data, valueSize);
int bytesLeftInStream = (int)(maximumItemSize - dataBytesRead);
if ((valueSize > 0) && (bytesLeftInStream > 0) && (dataBytesRead >= valueSize))
{
using (StreamBuffer dataBuffer = new StreamBuffer(data))
{
// See if there's a next item.
// Try to find the start of the next item.
long startPositionNextItem = stream.Position;
long bytesUntilNextItem = GetBytesUntilNextItem(version, stream, maximumItemSize - valueSize);
stream.Position = startPositionNextItem;
// Seems that the size indicated by the item is not the total size of the item; read the extra bytes here.
if (bytesUntilNextItem > 0)
{
data = new byte[bytesUntilNextItem];
stream.Read(data, data.Length);
dataBuffer.Write(data);
}
data = dataBuffer.ToByteArray();
}
}
Data = data;
return true;
}
////------------------------------------------------------------------------------------------------------------------------------
private static FlacMetadataBlock ReadBlock(StreamBuffer stream)
{
int flags = stream.ReadByte();
// Length
int length = stream.ReadBigEndianInt(3);
if (length >= stream.Length)
return null;
byte[] data = new byte[length];
stream.Read(data, length);
FlacMetadataBlock metadataBlock;
FlacMetadataBlockType blockType = (FlacMetadataBlockType)(flags & HeaderFlags.BlockType);
switch (blockType)
{
case FlacMetadataBlockType.Padding:
metadataBlock = new FlacPaddingMetadataBlock();
break;
case FlacMetadataBlockType.Application:
metadataBlock = new FlacApplicationMetadataBlock();
break;
case FlacMetadataBlockType.StreamInfo:
metadataBlock = new FlacStreamInfoMetadataBlock();
break;
case FlacMetadataBlockType.SeekTable:
metadataBlock = new FlacSeekTableMetadataBlock();
break;
case FlacMetadataBlockType.VorbisComment:
metadataBlock = new FlacVorbisCommentsMetadataBlock();
break;
case FlacMetadataBlockType.CueSheet:
metadataBlock = new FlacCueSheetMetadataBlock();
break;
case FlacMetadataBlockType.Picture:
metadataBlock = new FlacPictureMetadataBlock();
break;
default:
metadataBlock = new FlacMetadataBlock();
break;
}
metadataBlock.Flags = flags;
metadataBlock.Data = data;
return metadataBlock;
}
/// <summary>
/// Reads the <see cref="Id3v2FrameEncodingType"/> from the stream.
/// </summary>
/// <param name="streamBuffer">The stream buffer.</param>
/// <returns>
/// The <see cref="Id3v2FrameEncodingType"/>.
/// </returns>
/// <remarks>
/// Since the encoding type is first read from the stream, the position should be set to the byte containing the encoding type.
/// If the encoding type is <see cref="Id3v2FrameEncodingType.UTF16LittleEndian"/>,
/// it will try to read the byte order marker from the stream
/// to see if the encoding type is <see cref="Id3v2FrameEncodingType.UTF16BigEndian"/>.
/// If no byte order marker is found or if the byte order marker is not recognized,
/// it will return <see cref="Id3v2FrameEncodingType.UTF16LittleEndian"/> as default encoding.
/// <para />
/// The position of the stream will not be modified.
/// </remarks>
public static Id3v2FrameEncodingType ReadEncodingTypeFromStream(StreamBuffer streamBuffer)
{
int encodingByte = streamBuffer.ReadByte();
if ((encodingByte == -1) || !IsValidEncodingType(encodingByte))
return Id3v2FrameEncodingType.Default;
if (encodingByte > (byte)Id3v2FrameEncodingType.UTF16LittleEndian)
encodingByte += 1;
// Cast the encoding type.
Id3v2FrameEncodingType encodingType = (Id3v2FrameEncodingType)encodingByte;
// If it's not little endian, then we don't need to figure out if it's little or big; return here.
if (encodingType != Id3v2FrameEncodingType.UTF16LittleEndian)
return encodingType;
// See which byte order the frame encoding is.
byte[] byteOrderMarker = new byte[2];
// Not enough bytes available; probably little endian then.
if (streamBuffer.Read(byteOrderMarker, 2, false) < 2)
return Id3v2FrameEncodingType.UTF16LittleEndian;
// Little endian byte order marker?
if (((byteOrderMarker[0] == 0xFF) && (byteOrderMarker[1] == 0xFE))
|| ((byteOrderMarker[0] == 0x00) && (byteOrderMarker[1] == 0x00)))
return Id3v2FrameEncodingType.UTF16LittleEndian;
// Big endian byte order marker?
if ((byteOrderMarker[0] == 0xFE) && (byteOrderMarker[1] == 0xFF))
return Id3v2FrameEncodingType.UTF16BigEndian;
// Default to little endian.
return Id3v2FrameEncodingType.UTF16LittleEndian;
}
public void ReadTestMovePositionTrue()
{
byte[] msBuffer = { 0x90, 0x10, 0xAA, 0x02, 0xFF };
StreamBuffer target = new StreamBuffer(msBuffer);
byte[] buffer = new byte[msBuffer.Length];
target.Read(buffer, msBuffer.Length);
Assert.IsTrue(target.Position == msBuffer.Length);
}
public void ReadTestByteArraysAreEqualUsingMemoryStream()
{
byte[] msBuffer = { 0x90, 0x10, 0xAA, 0x02, 0xFF };
MemoryStream ms = new MemoryStream(msBuffer);
StreamBuffer target = new StreamBuffer(ms);
byte[] buffer = new byte[msBuffer.Length];
target.Read(buffer, 0, msBuffer.Length);
Assert.IsTrue(msBuffer.SequenceEqual(buffer));
}
public void ReadTestAmountOfBytesReadUsingMemoryStream()
{
byte[] msBuffer = { 0x90, 0x10, 0xAA, 0x02, 0xFF };
MemoryStream ms = new MemoryStream(msBuffer);
StreamBuffer target = new StreamBuffer(ms);
byte[] buffer = new byte[msBuffer.Length];
int expected = msBuffer.Length;
int actual = target.Read(buffer, 0, expected);
Assert.AreEqual(expected, actual);
}
