private unsafe bool ParseHeader(ref byte *headerBuffer, FlacMetadataStreamInfo streamInfo)
{
const string loggerLocation = "FlacFrameHeader.ParseHeader(byte*, FlacMetadataStreamInfo)";
if (headerBuffer[0] == 0xFF && headerBuffer[1] >> 1 == 0x7C) //sync bits
{
if ((headerBuffer[1] & 0x02) != 0)
{
Error("Invalid FlacFrame. Reservedbit_0 is 1", loggerLocation);
return(false);
}
var __headerbufferPtr = headerBuffer;
var reader = new FlacBitReader(__headerbufferPtr, 0);
#region blocksize
//blocksize
var val = headerBuffer[2] >> 4;
var blocksize = -1;
if (val == 0)
{
Error("Invalid Blocksize value: 0", loggerLocation);
return(false);
}
if (val == 1)
{
blocksize = 192;
}
else if (val >= 2 && val <= 5)
{
blocksize = 576 << (val - 2);
}
else if (val == 6 || val == 7)
{
_blocksizeHint = val;
}
else if (val >= 8 && val <= 15)
{
blocksize = 256 << (val - 8);
}
else
{
Error("Invalid Blocksize value: " + val, loggerLocation);
return(false);
}
BlockSize = blocksize;
#endregion blocksize
#region samplerate
//samplerate
val = headerBuffer[2] & 0x0F;
var sampleRate = -1;
if (val == 0)
{
if (streamInfo != null)
{
sampleRate = streamInfo.SampleRate;
}
else
{
Error("Missing Samplerate. Samplerate Index = 0 && streamInfoMetaData == null.", loggerLocation);
return(false);
}
}
else if (val >= 1 && val <= 11)
{
sampleRate = FlacConstant.SampleRateTable[val];
}
else if (val >= 12 && val <= 14)
{
_sampleRateHint = val;
}
else
{
Error("Invalid SampleRate value: " + val, loggerLocation);
return(false);
}
SampleRate = sampleRate;
#endregion samplerate
#region channels
val = headerBuffer[3] >> 4; //cc: unsigned
int channels;
if ((val & 8) != 0)
{
channels = 2;
if ((val & 7) > 2 || (val & 7) < 0)
{
Error("Invalid ChannelAssignment", loggerLocation);
return(false);
}
ChannelAssignment = (ChannelAssignment)((val & 7) + 1);
}
else
{
channels = val + 1;
ChannelAssignment = ChannelAssignment.Independent;
}
Channels = channels;
#endregion channels
#region bitspersample
val = (headerBuffer[3] & 0x0E) >> 1;
int bitsPerSample;
if (val == 0)
{
if (streamInfo != null)
{
bitsPerSample = streamInfo.BitsPerSample;
}
else
{
Error("Missing BitsPerSample. Index = 0 && streamInfoMetaData == null.", loggerLocation);
return(false);
}
}
else if (val == 3 || val >= 7 || val < 0)
{
Error("Invalid BitsPerSampleIndex", loggerLocation);
return(false);
}
else
{
bitsPerSample = FlacConstant.BitPerSampleTable[val];
}
BitsPerSample = bitsPerSample;
#endregion bitspersample
if ((headerBuffer[3] & 0x01) != 0) // reserved bit -> 0
{
Error("Invalid FlacFrame. Reservedbit_1 is 1", loggerLocation);
return(false);
}
reader.ReadBits(32); //skip the first 4 bytes since they got already processed
//BYTE 4
#region utf8
//variable blocksize
if ((headerBuffer[1] & 0x01) != 0 ||
(streamInfo != null && streamInfo.MinBlockSize != streamInfo.MaxBlockSize))
{
if (reader.ReadUTF8_64(out var samplenumber) && samplenumber != ulong.MaxValue)
{
BlockingStrategy = BlockingStrategy.VariableBlockSize;
SampleNumber = (long)samplenumber;
}
else
{
Error("Invalid UTF8 Samplenumber coding.", loggerLocation);
return(false);
}
}
else //fixed blocksize
{
if (reader.ReadUTF8_32(out var framenumber) && framenumber != uint.MaxValue)
{
BlockingStrategy = BlockingStrategy.FixedBlockSize;
FrameNumber = (int)framenumber;
}
/// <summary>
/// Initializes a new instance of the <see cref="FlacFrameHeader"/> class.
/// </summary>
/// <param name="buffer">The raw byte-data which contains the <see cref="FlacFrameHeader"/>.</param>
/// <param name="streamInfo">The stream-info-metadata-block of the flac stream which provides some basic information about the flac framestream. Can be set to null.</param>
/// <param name="doCrc">A value which indicates whether the crc8 checksum of the <see cref="FlacFrameHeader"/> should be calculated.</param>
public unsafe FlacFrameHeader(ref byte *buffer, FlacMetadataStreamInfo streamInfo, bool doCrc)
: this(ref buffer, streamInfo, doCrc, true)
{
}
