/// <summary>
/// Skip over any whitespace or any comments.
/// </summary>
public static void SkipWhitespaceAndComments(this BufferedReadStream stream)
{
bool isWhitespace;
do
{
int val = stream.ReadByte();
// Comments start with '#' and end at the next new-line.
if (val == 0x23)
{
int innerValue;
do
{
innerValue = stream.ReadByte();
}while (innerValue != 0x0a);
// Continue searching for whitespace.
val = innerValue;
}
isWhitespace = val is 0x09 or 0x0a or 0x0d or 0x20;
}while (isWhitespace);
stream.Seek(-1, SeekOrigin.Current);
}
/// <summary>
/// Decompresses image data into the supplied buffer.
/// </summary>
/// <param name="stream">The <see cref="Stream" /> to read image data from.</param>
/// <param name="stripOffset">The strip offset of stream.</param>
/// <param name="stripByteCount">The number of bytes to read from the input stream.</param>
/// <param name="stripHeight">The height of the strip.</param>
/// <param name="buffer">The output buffer for uncompressed data.</param>
public void Decompress(BufferedReadStream stream, ulong stripOffset, ulong stripByteCount, int stripHeight, Span <byte> buffer)
{
DebugGuard.MustBeLessThanOrEqualTo(stripOffset, (ulong)long.MaxValue, nameof(stripOffset));
DebugGuard.MustBeLessThanOrEqualTo(stripByteCount, (ulong)long.MaxValue, nameof(stripByteCount));
stream.Seek((long)stripOffset, SeekOrigin.Begin);
this.Decompress(stream, (int)stripByteCount, stripHeight, buffer);
if ((long)stripOffset + (long)stripByteCount < stream.Position)
{
TiffThrowHelper.ThrowImageFormatException("Out of range when reading a strip.");
}
}
/// <summary>
/// Decompresses image data into the supplied buffer.
/// </summary>
/// <param name="stream">The <see cref="Stream" /> to read image data from.</param>
/// <param name="stripOffset">The strip offset of stream.</param>
/// <param name="stripByteCount">The number of bytes to read from the input stream.</param>
/// <param name="stripHeight">The height of the strip.</param>
/// <param name="buffer">The output buffer for uncompressed data.</param>
public void Decompress(BufferedReadStream stream, uint stripOffset, uint stripByteCount, int stripHeight, Span <byte> buffer)
{
if (stripByteCount > int.MaxValue)
{
TiffThrowHelper.ThrowImageFormatException("The StripByteCount value is too big.");
}
stream.Seek(stripOffset, SeekOrigin.Begin);
this.Decompress(stream, (int)stripByteCount, stripHeight, buffer);
if (stripOffset + stripByteCount < stream.Position)
{
TiffThrowHelper.ThrowImageFormatException("Out of range when reading a strip.");
}
}
protected override int ReadNextByte()
{
if (_curOfs == _length)
{
if (_mergedPacket == null)
{
return(-1);
}
return(_mergedPacket.ReadNextByte());
}
_stream.Seek(_curOfs + _offset, SeekOrigin.Begin);
var b = _stream.ReadByte();
++_curOfs;
return(b);
}
PageHeader ReadPageHeader(long position)
{
// set the stream's position
_stream.Seek(position, SeekOrigin.Begin);
// header
// NB: if the stream didn't have an EOS flag, this is the most likely spot for the EOF to be found...
if (_stream.Read(_readBuffer, 0, 27) != 27)
{
return(null);
}
// capture signature
if (_readBuffer[0] != 0x4f || _readBuffer[1] != 0x67 || _readBuffer[2] != 0x67 || _readBuffer[3] != 0x53)
{
return(null);
}
// check the stream version
if (_readBuffer[4] != 0)
{
return(null);
}
// start populating the header
var hdr = new PageHeader();
// bit flags
hdr.Flags = (PageFlags)_readBuffer[5];
// granulePosition
hdr.GranulePosition = BitConverter.ToInt64(_readBuffer, 6);
// stream serial
hdr.StreamSerial = BitConverter.ToInt32(_readBuffer, 14);
// sequence number
hdr.SequenceNumber = BitConverter.ToInt32(_readBuffer, 18);
// save off the CRC
var crc = BitConverter.ToUInt32(_readBuffer, 22);
// start calculating the CRC value for this page
_crc.Reset();
for (int i = 0; i < 22; i++)
{
_crc.Update(_readBuffer[i]);
}
_crc.Update(0);
_crc.Update(0);
_crc.Update(0);
_crc.Update(0);
_crc.Update(_readBuffer[26]);
// figure out the length of the page
var segCnt = (int)_readBuffer[26];
if (_stream.Read(_readBuffer, 0, segCnt) != segCnt)
{
return(null);
}
var packetSizes = new List <int>(segCnt);
int size = 0, idx = 0;
for (int i = 0; i < segCnt; i++)
{
var temp = _readBuffer[i];
_crc.Update(temp);
if (idx == packetSizes.Count)
{
packetSizes.Add(0);
}
packetSizes[idx] += temp;
if (temp < 255)
{
++idx;
hdr.LastPacketContinues = false;
}
else
{
hdr.LastPacketContinues = true;
}
size += temp;
}
hdr.PacketSizes = packetSizes.ToArray();
hdr.DataOffset = position + 27 + segCnt;
// now we have to go through every byte in the page
if (_stream.Read(_readBuffer, 0, size) != size)
{
return(null);
}
for (int i = 0; i < size; i++)
{
_crc.Update(_readBuffer[i]);
}
if (_crc.Test(crc))
{
_containerBits += 8 * (27 + segCnt);
++_pageCount;
return(hdr);
}
return(null);
}
public PageHeader ReadPageHeader(long position)
{
_stream.Seek(position, SeekOrigin.Begin);
if (_stream.Read(_readBuffer, 0, 27) != 27)
{
return(null);
}
if (_readBuffer[0] != 79 || _readBuffer[1] != 103 || _readBuffer[2] != 103 || _readBuffer[3] != 83)
{
return(null);
}
if (_readBuffer[4] != 0)
{
return(null);
}
PageHeader pageHeader = new PageHeader();
pageHeader.Flags = (PageFlags)_readBuffer[5];
long num = BitConverter.ToInt32(_readBuffer, 6);
long num2 = BitConverter.ToInt32(_readBuffer, 10);
pageHeader.GranulePosition = num + (num2 << 32);
pageHeader.StreamSerial = BitConverter.ToInt32(_readBuffer, 14);
pageHeader.SequenceNumber = BitConverter.ToInt32(_readBuffer, 18);
uint checkCrc = BitConverter.ToUInt32(_readBuffer, 22);
_crc.Reset();
for (int i = 0; i < 22; i++)
{
_crc.Update(_readBuffer[i]);
}
_crc.Update(0);
_crc.Update(0);
_crc.Update(0);
_crc.Update(0);
_crc.Update(_readBuffer[26]);
int num3 = _readBuffer[26];
if (_stream.Read(_readBuffer, 0, num3) != num3)
{
return(null);
}
List <int> list = new List <int>(num3);
int num4 = 0;
int num5 = 0;
for (int j = 0; j < num3; j++)
{
byte b = _readBuffer[j];
_crc.Update(b);
if (num5 == list.Count)
{
list.Add(0);
}
list[num5] += b;
if (b < byte.MaxValue)
{
num5++;
pageHeader.LastPacketContinues = false;
}
else
{
pageHeader.LastPacketContinues = true;
}
num4 += b;
}
pageHeader.PacketSizes = list.ToArray();
pageHeader.DataOffset = position + 27 + num3;
if (_stream.Read(_readBuffer, 0, num4) != num4)
{
return(null);
}
for (int k = 0; k < num4; k++)
{
_crc.Update(_readBuffer[k]);
}
if (_crc.Test(checkCrc))
{
_containerBits += 8 * (27 + num3);
_pageCount++;
return(pageHeader);
}
return(null);
}
private unsafe bool ReadPageHeader(long position, out PageHeader header)
{
header = default;
// set the stream's position
_stream.Seek(position, SeekOrigin.Begin);
// header
// NB: if the stream didn't have an EOS flag, this is the most likely spot for the EOF to be found...
if (_stream.Read(_readBuffer, 0, 27) != 27)
{
return(false);
}
// capture signature
if (_readBuffer[0] != 0x4f || _readBuffer[1] != 0x67 || _readBuffer[2] != 0x67 || _readBuffer[3] != 0x53)
{
return(false);
}
// check the stream version
if (_readBuffer[4] != 0)
{
return(false);
}
// start populating the header
header = new PageHeader();
// bit flags
header.Flags = (OggPageFlags)_readBuffer[5];
// granulePosition
header.GranulePosition = BitConverter.ToInt64(_readBuffer, 6);
// stream serial
header.StreamSerial = BitConverter.ToInt32(_readBuffer, 14);
// sequence number
header.SequenceNumber = BitConverter.ToInt32(_readBuffer, 18);
// save off the CRC
var crc = BitConverter.ToUInt32(_readBuffer, 22);
// start calculating the CRC value for this page
_crc.Reset();
for (int i = 0; i < 22; i++)
{
_crc.Update(_readBuffer[i]);
}
_crc.Update(0);
_crc.Update(0);
_crc.Update(0);
_crc.Update(0);
_crc.Update(_readBuffer[26]);
// figure out the length of the page
header.SegCount = _readBuffer[26];
if (_stream.Read(_readBuffer, 0, header.SegCount) != header.SegCount)
{
return(false);
}
int size = 0;
int idx = 0;
for (int i = 0; i < header.SegCount; i++)
{
var tmp = _readBuffer[i];
_crc.Update(tmp);
header.PacketSizes[idx] += tmp;
if (tmp < 255)
{
idx++;
header.LastPacketContinues = false;
}
else
{
header.LastPacketContinues = true;
}
size += tmp;
}
header.DataOffset = position + 27 + header.SegCount;
// now we have to go through every byte in the page
if (_stream.Read(_readBuffer, 0, size) != size)
{
return(false);
}
for (int i = 0; i < size; i++)
{
_crc.Update(_readBuffer[i]);
}
if (_crc.Test(crc))
{
_containerBits += 8 * (27 + header.SegCount);
++_pageCount;
return(true);
}
return(false);
}
