private void Handle_IDAT(PNGChunk chunk)
{
IDATChunk idatC = new IDATChunk();
idatC.ChunkData = chunk.ChunkData;
IDATList.Add(idatC);
}
protected PNGChunk GetNextChunk(Stream stream)
{
PNGChunk value = new PNGChunk();
byte[] size = new byte[sizeof(uint)];
stream.Read(size, 0, sizeof(uint));
uint readLength = PNGUtils.ParseUint(size);
byte[] type = new byte[4];
stream.Read(type, 0, 4);
value.ChunkType = PNGUtils.ParseString(type, 4);
byte[] data = new byte[readLength];
stream.Read(data, 0, (int)readLength);
value.ChunkData = data;
byte[] crc = new byte[sizeof(uint)];
stream.Read(crc, 0, sizeof(uint));
uint readCRC = PNGUtils.ParseUint(crc);
uint calcCRC = value.CalculateCRC();
if (readCRC != calcCRC)
{
throw new ApplicationException($"PNG Chunk CRC Mismatch. Chunk CRC = {readCRC}, Calculated CRC = {calcCRC}.");
}
return(value);
}
private void Handle_iTXt(PNGChunk chunk)
{
iTXtChunk it = new iTXtChunk();
it.ChunkData = chunk.ChunkData;
iTXtList.Add(it);
}
private void Handle_tEXt(PNGChunk chunk)
{
tEXtChunk txt = new tEXtChunk();
txt.ChunkData = chunk.ChunkData;
tEXtList.Add(txt);
}
private void Handle_tRNS(PNGChunk chunk)
{
if (tRNS != null)
{
throw new ApplicationException("tRNS chunk encountered more than once");
}
switch (IHDR.ColorType)
{
case 0:
tRNS = new tRNSChunkType0();
break;
case 2:
tRNS = new tRNSChunkType2();
break;
case 3:
tRNS = new tRNSChunkType3();
break;
case 4:
case 6:
throw new ApplicationException("tRNS chunk encountered, Colour type does not support");
default:
throw new ApplicationException("Colour type is not supported");
}
tRNS.ChunkData = chunk.ChunkData;
}
private void Handle_sBIT(PNGChunk chunk)
{
if (sBIT != null)
{
throw new ApplicationException("sBIT chunk encountered more than once");
}
switch (IHDR.ColorType)
{
case 0:
sBIT = new sBITChunkType0();
break;
case 2:
sBIT = new sBITChunkType2();
break;
case 3:
sBIT = new sBITChunkType3();
break;
case 4:
sBIT = new sBITChunkType4();
break;
case 6:
sBIT = new sBITChunkType6();
break;
default:
throw new ApplicationException("Colour type is not supported");
}
sBIT.ChunkData = chunk.ChunkData;
}
public void Load(Stream stream)
{
Stopwatch stopWatch = new Stopwatch();
stopWatch.Start();
Console.WriteLine("\nReading file...");
byte[] sig = new byte[PNGSignature.Signature.Length];
stream.Read(sig, 0, PNGSignature.Signature.Length);
PNGSignature.Compare(sig);
PNGChunk chunk = GetNextChunk(stream);
Console.WriteLine($"Reading {chunk.ChunkType} chunk... ({chunk.ChunkLength} bytes)");
if (chunk.ChunkType != IHDRChunk.NAME)
{
throw new ApplicationException("First chunk is not IHDR chunk");
}
Handle_IHDR(chunk);
do
{
chunk = GetNextChunk(stream);
Console.WriteLine($"Reading {chunk.ChunkType} chunk... ({chunk.ChunkLength} bytes)");
if (!HandleChunk(chunk))
{
HandleDefaultChunk(chunk);
}
} while (chunk.ChunkType != IENDChunk.NAME);
Validate();
stopWatch.Stop();
string elapsedTime = stopWatch.Elapsed.FormatTime();
Console.WriteLine($"Total read time = {elapsedTime}");
}
private void Handle_bKGD(PNGChunk chunk)
{
if (bKGD != null)
{
throw new ApplicationException("bKGD chunk encountered more than once");
}
switch (IHDR.ColorType)
{
case 0:
bKGD = new bKGDChunkType0();
break;
case 2:
bKGD = new bKGDChunkType2();
break;
case 3:
bKGD = new bKGDChunkType3();
break;
case 4:
bKGD = new bKGDChunkType4();
break;
case 6:
bKGD = new bKGDChunkType6();
break;
default:
throw new ApplicationException("Colour type is not supported");
}
bKGD.ChunkData = chunk.ChunkData;
}
private void Handle_zTXt(PNGChunk chunk)
{
zTXtChunk zt = new zTXtChunk();
zt.ChunkData = chunk.ChunkData;
zTXtList.Add(zt);
}
private void Handle_PLTE(PNGChunk chunk)
{
if (PLTE != null)
{
throw new ApplicationException("PLTE chunk encountered more than once");
}
PLTE = new PLTEChunk();
PLTE.ChunkData = chunk.ChunkData;
}
private void Handle_cHRM(PNGChunk chunk)
{
if (cHRM != null)
{
throw new ApplicationException("cHRM chunk encountered more than once");
}
cHRM = new cHRMChunk();
cHRM.ChunkData = chunk.ChunkData;
}
private void Handle_gAMA(PNGChunk chunk)
{
if (gAMA != null)
{
throw new ApplicationException("gAMA chunk encountered more than once");
}
gAMA = new gAMAChunk();
gAMA.ChunkData = chunk.ChunkData;
}
private void Handle_iCCP(PNGChunk chunk)
{
if (iCCP != null)
{
throw new ApplicationException("iCCP chunk encountered more than once");
}
iCCP = new iCCPChunk();
iCCP.ChunkData = chunk.ChunkData;
}
private void Handle_sRGB(PNGChunk chunk)
{
if (sRGB != null)
{
throw new ApplicationException("sRGB chunk encountered more than once");
}
sRGB = new sRGBChunk();
sRGB.ChunkData = chunk.ChunkData;
}
private void Handle_IHDR(PNGChunk chunk)
{
if (IHDR != null)
{
throw new ApplicationException("IHDR defined more than once");
}
IHDR = new IHDRChunk();
IHDR.ChunkData = chunk.ChunkData;
}
private void Handle_hIST(PNGChunk chunk)
{
if (hIST != null)
{
throw new ApplicationException("hIST chunk encountered more than once");
}
hIST = new hISTChunk();
hIST.ChunkData = chunk.ChunkData;
}
private void Handle_pHYs(PNGChunk chunk)
{
if (pHYs != null)
{
throw new ApplicationException("pHYs chunk encountered more than once");
}
pHYs = new pHYsChunk();
pHYs.ChunkData = chunk.ChunkData;
}
private void Handle_sPLT(PNGChunk chunk)
{
if (sPLT != null)
{
throw new ApplicationException("sPLT chunk encountered more than once");
}
sPLT = new sPLTChunk();
sPLT.ChunkData = chunk.ChunkData;
}
private void Handle_tIME(PNGChunk chunk)
{
if (tIME != null)
{
throw new ApplicationException("tIME chunk encountered more than once");
}
tIME = new tIMEChunk();
tIME.ChunkData = chunk.ChunkData;
}
protected static void WriteChunk(Stream stream, PNGChunk chunk)
{
if (chunk != null)
{
Console.WriteLine($"Writing {chunk.ChunkType} chunk... ({chunk.ChunkLength} bytes)");
byte[] chArray = chunk.Chunk;
stream.Write(chArray, 0, chArray.Length);
}
}
private void Handle_IEND(PNGChunk chunk)
{
if (IEND != null)
{
throw new ApplicationException("IEND defined more than once");
}
IEND = new IENDChunk();
IEND.ChunkData = chunk.ChunkData;
}
private void HandleDefaultChunk(PNGChunk chunk)
{
chunks.Add(chunk);
}
protected virtual bool HandleChunk(PNGChunk chunk)
{
switch (chunk.ChunkType)
{
case IHDRChunk.NAME:
Handle_IHDR(chunk);
break;
case PLTEChunk.NAME:
Handle_PLTE(chunk);
break;
case IDATChunk.NAME:
Handle_IDAT(chunk);
break;
case IENDChunk.NAME:
Handle_IEND(chunk);
break;
case tRNSChunk.NAME:
Handle_tRNS(chunk);
break;
case cHRMChunk.NAME:
Handle_cHRM(chunk);
break;
case gAMAChunk.NAME:
Handle_gAMA(chunk);
break;
case iCCPChunk.NAME:
Handle_iCCP(chunk);
break;
case sBITChunk.NAME:
Handle_sBIT(chunk);
break;
case sRGBChunk.NAME:
Handle_sRGB(chunk);
break;
case tEXtChunk.NAME:
Handle_tEXt(chunk);
break;
case zTXtChunk.NAME:
Handle_zTXt(chunk);
break;
case iTXtChunk.NAME:
Handle_iTXt(chunk);
break;
case bKGDChunk.NAME:
Handle_bKGD(chunk);
break;
case hISTChunk.NAME:
Handle_hIST(chunk);
break;
case pHYsChunk.NAME:
Handle_pHYs(chunk);
break;
case sPLTChunk.NAME:
Handle_sPLT(chunk);
break;
case tIMEChunk.NAME:
Handle_tIME(chunk);
break;
default:
return(false);
}
return(true);
}
