protected void ReadHeader()
{
byte[] bytes = new byte[4];
m_stream.Read(bytes, 0, 4);
UInt32 magicNumber = BitConverter.ToUInt32(bytes, 0);
if (magicNumber != BinaryConstants.PROTEAN_MAGIC)
{
throw new VariantException("Invalid magic number");
}
// ignore version info for now
m_stream.Read(bytes, 0, 4);
m_stream.Read(bytes, 0, 4);
m_mode = (BinaryMode)System.BitConverter.ToUInt32(bytes, 0);
if ((m_mode & BinaryMode.Compress) != 0)
{
if ((m_mode & BinaryMode.ZlibHeader) != 0)
{
throw new VariantException("Binary data appears to contain ZLIB header which is currently not supported in the protean.NET BinaryReader");
}
System.IO.Compression.DeflateStream deflateStream = new System.IO.Compression.DeflateStream(m_stream, System.IO.Compression.CompressionMode.Decompress, true);
if (m_requireSeekableReader)
{
MemoryStream deflatedStream = new MemoryStream();
int value;
while ((value = deflateStream.ReadByte()) != -1)
{
deflatedStream.WriteByte((byte)value);
}
m_filter = new MemoryStream(deflatedStream.ToArray(), 0, (int)deflatedStream.Length, false);
}
else
{
m_filter = deflateStream;
}
}
}
protected void ReadHeader()
{
byte[] bytes = new byte[4];
m_stream.Read(bytes, 0, 4);
UInt32 magicNumber = BitConverter.ToUInt32(bytes, 0);
if (magicNumber != BinaryConstants.PROTEAN_MAGIC)
{
throw new VariantException("Invalid magic number");
}
// ignore version info for now
m_stream.Read(bytes, 0, 4);
m_stream.Read(bytes, 0, 4);
m_mode = (BinaryMode)System.BitConverter.ToUInt32(bytes, 0);
if ((m_mode & BinaryMode.Compress) != 0)
{
if ((m_mode & BinaryMode.ZlibHeader) != 0)
{
throw new VariantException("Binary data appears to contain ZLIB header which is currently not supported in the protean.NET BinaryReader");
}
System.IO.Compression.DeflateStream deflateStream = new System.IO.Compression.DeflateStream(m_stream, System.IO.Compression.CompressionMode.Decompress, true);
if (m_requireSeekableReader)
{
MemoryStream deflatedStream = new MemoryStream();
int value;
while ((value = deflateStream.ReadByte()) != -1)
{
deflatedStream.WriteByte((byte)value);
}
m_filter = new MemoryStream(deflatedStream.ToArray(), 0, (int)deflatedStream.Length, false);
}
else
{
m_filter = deflateStream;
}
}
}
private void ReadScanlines(MemoryStream dataStream, byte[] pixels, IColorReader colorReader, PngColorTypeInformation colorTypeInformation)
{
// Read the zlib header : http://tools.ietf.org/html/rfc1950
// CMF(Compression Method and flags)
// This byte is divided into a 4 - bit compression method and a
// 4-bit information field depending on the compression method.
// bits 0 to 3 CM Compression method
// bits 4 to 7 CINFO Compression info
//
// 0 1
// +---+---+
// |CMF|FLG|
// +---+---+
int cmf = dataStream.ReadByte();
int flag = dataStream.ReadByte();
//please note that position=2
int scanlineLength = CalculateScanlineLength(colorTypeInformation);
int scanlineStep = CalculateScanlineStep(colorTypeInformation);
byte[] lastScanline = new byte[scanlineLength];
byte[] currScanline = new byte[scanlineLength];
byte a = 0;
byte b = 0;
byte c = 0;
int row = 0, filter = 0, column = -1;
//using (InflaterInputStream compressedStream = new InflaterInputStream(dataStream))
//{
// int readByte = 0;
// while ((readByte = compressedStream.ReadByte()) >= 0)
// {
// if (column == -1)
// {
// filter = readByte;
// column++;
// }
// else
// {
// currScanline[column] = (byte)readByte;
// if (column >= scanlineStep)
// {
// a = currScanline[column - scanlineStep];
// c = lastScanline[column - scanlineStep];
// }
// else
// {
// a = 0;
// c = 0;
// }
// b = lastScanline[column];
// if (filter == 1)
// {
// currScanline[column] = (byte)(currScanline[column] + a);
// }
// else if (filter == 2)
// {
// currScanline[column] = (byte)(currScanline[column] + b);
// }
// else if (filter == 3)
// {
// currScanline[column] = (byte)(currScanline[column] + (byte)Math.Floor((double)(a + b) / 2));
// }
// else if (filter == 4)
// {
// currScanline[column] = (byte)(currScanline[column] + PaethPredicator(a, b, c));
// }
// column++;
// if (column == scanlineLength)
// {
// colorReader.ReadScanline(currScanline, pixels, _header);
// column = -1;
// row++;
// Extensions.Swap(ref currScanline, ref lastScanline);
// }
// }
// }
//}
//using (Ionic.Zlib.DeflateStream compressedStream = new Ionic.Zlib.DeflateStream(dataStream, Ionic.Zlib.CompressionMode.Decompress))
using (System.IO.Compression.DeflateStream compressedStream = new System.IO.Compression.DeflateStream(
dataStream,
System.IO.Compression.CompressionMode.Decompress, true))
{
int readByte = 0;
//byte[] singleByte = new byte[1];
//compressedStream.Read(singleByte, 0, 1);
while ((readByte = compressedStream.ReadByte()) >= 0)
{
if (column == -1)
{
filter = readByte;
column++;
}
else
{
currScanline[column] = (byte)readByte;
if (column >= scanlineStep)
{
a = currScanline[column - scanlineStep];
c = lastScanline[column - scanlineStep];
}
else
{
a = 0;
c = 0;
}
b = lastScanline[column];
if (filter == 1)
{
currScanline[column] = (byte)(currScanline[column] + a);
}
else if (filter == 2)
{
currScanline[column] = (byte)(currScanline[column] + b);
}
else if (filter == 3)
{
currScanline[column] = (byte)(currScanline[column] + (byte)Math.Floor((double)(a + b) / 2));
}
else if (filter == 4)
{
currScanline[column] = (byte)(currScanline[column] + PaethPredicator(a, b, c));
}
column++;
if (column == scanlineLength)
{
colorReader.ReadScanline(currScanline, pixels, _header);
column = -1;
row++;
//
//Extensions.Swap(ref currScanline, ref lastScanline);
var tmpA = currScanline;
var tmpB = lastScanline;
lastScanline = tmpA;
currScanline = tmpB;
}
}
}
}
}
private void ReadScanlines(MemoryStream dataStream, byte[] pixels, IColorReader colorReader, PngColorTypeInformation colorTypeInformation)
{
// Read the zlib header : http://tools.ietf.org/html/rfc1950
// CMF(Compression Method and flags)
// This byte is divided into a 4 - bit compression method and a
// 4-bit information field depending on the compression method.
// bits 0 to 3 CM Compression method
// bits 4 to 7 CINFO Compression info
//
// 0 1
// +---+---+
// |CMF|FLG|
// +---+---+
int cmf = dataStream.ReadByte();
int flag = dataStream.ReadByte();
//please note that position=2
int scanlineLength = CalculateScanlineLength(colorTypeInformation);
int scanlineStep = CalculateScanlineStep(colorTypeInformation);
byte[] lastScanline = new byte[scanlineLength];
byte[] currScanline = new byte[scanlineLength];
byte a = 0;
byte b = 0;
byte c = 0;
int row = 0, filter = 0, column = -1;
//using (InflaterInputStream compressedStream = new InflaterInputStream(dataStream))
//{
// int readByte = 0;
// while ((readByte = compressedStream.ReadByte()) >= 0)
// {
// if (column == -1)
// {
// filter = readByte;
// column++;
// }
// else
// {
// currScanline[column] = (byte)readByte;
// if (column >= scanlineStep)
// {
// a = currScanline[column - scanlineStep];
// c = lastScanline[column - scanlineStep];
// }
// else
// {
// a = 0;
// c = 0;
// }
// b = lastScanline[column];
// if (filter == 1)
// {
// currScanline[column] = (byte)(currScanline[column] + a);
// }
// else if (filter == 2)
// {
// currScanline[column] = (byte)(currScanline[column] + b);
// }
// else if (filter == 3)
// {
// currScanline[column] = (byte)(currScanline[column] + (byte)Math.Floor((double)(a + b) / 2));
// }
// else if (filter == 4)
// {
// currScanline[column] = (byte)(currScanline[column] + PaethPredicator(a, b, c));
// }
// column++;
// if (column == scanlineLength)
// {
// colorReader.ReadScanline(currScanline, pixels, _header);
// column = -1;
// row++;
// Extensions.Swap(ref currScanline, ref lastScanline);
// }
// }
// }
//}
using (System.IO.Compression.DeflateStream compressedStream = new System.IO.Compression.DeflateStream(
dataStream,
System.IO.Compression.CompressionMode.Decompress, true))
//using (Ionic.Zlib.DeflateStream compressedStream = new Ionic.Zlib.DeflateStream(dataStream, Ionic.Zlib.CompressionMode.Decompress))
{
int readByte = 0;
//byte[] singleByte = new byte[1];
//compressedStream.Read(singleByte, 0, 1);
while ((readByte = compressedStream.ReadByte()) >= 0)
{
if (column == -1)
{
filter = readByte;
column++;
}
else
{
currScanline[column] = (byte)readByte;
if (column >= scanlineStep)
{
a = currScanline[column - scanlineStep];
c = lastScanline[column - scanlineStep];
}
else
{
a = 0;
c = 0;
}
b = lastScanline[column];
if (filter == 1)
{
currScanline[column] = (byte)(currScanline[column] + a);
}
else if (filter == 2)
{
currScanline[column] = (byte)(currScanline[column] + b);
}
else if (filter == 3)
{
currScanline[column] = (byte)(currScanline[column] + (byte)Math.Floor((double)(a + b) / 2));
}
else if (filter == 4)
{
currScanline[column] = (byte)(currScanline[column] + PaethPredicator(a, b, c));
}
column++;
if (column == scanlineLength)
{
colorReader.ReadScanline(currScanline, pixels, _header);
column = -1;
row++;
//
//Extensions.Swap(ref currScanline, ref lastScanline);
var tmpA = currScanline;
var tmpB = lastScanline;
lastScanline = tmpA;
currScanline = tmpB;
}
}
}
}
}