private YCbCrImage ycbcrImage; // YCrCb
#endregion Fields
#region Constructors
public JpegDecoderCore()
{
huff = new Huffman[maxTc + 1, maxTh + 1];
quant = new Block[maxTq + 1];
tmp = new byte[2*Block.blockSize];
comp = new Component[maxComponents];
progCoeffs = new Block[maxComponents][];
bits = new BitsClass();
bytes = new BytesClass();
for (int i = 0; i < maxTc + 1; i++){
for (int j = 0; j < maxTh + 1; j++){
huff[i, j] = new Huffman();
}
}
for (int i = 0; i < quant.Length; i++){
quant[i] = new Block();
}
for (int i = 0; i < comp.Length; i++){
comp[i] = new Component();
}
}
private int WriteBlock(Block block, QuantIndex index, int prevDc)
{
FDCT.Transform(block);
int dc = Round(block[0], 8*quant[(int) index][0]);
EmitHuffRle((HuffIndex) (2*(int) index + 0), 0, dc - prevDc);
var h = (HuffIndex) (2*(int) index + 1);
int runLength = 0;
for (int zig = 1; zig < Block.blockSize; zig++){
int ac = Round(block[unzig[zig]], 8*quant[(int) index][zig]);
if (ac == 0){
runLength++;
} else{
while (runLength > 15){
EmitHuff(h, 0xf0);
runLength -= 16;
}
EmitHuffRle(h, runLength, ac);
runLength = 0;
}
}
if (runLength > 0){
EmitHuff(h, 0x00);
}
return dc;
}
private void Encode444(IPixelAccessor pixels)
{
Block b = new Block();
Block cb = new Block();
Block cr = new Block();
int prevDcy = 0, prevDcCb = 0, prevDcCr = 0;
for (int y = 0; y < pixels.Height; y += 8){
for (int x = 0; x < pixels.Width; x += 8){
ToYCbCr(pixels, x, y, b, cb, cr);
prevDcy = WriteBlock(b, QuantIndex.Luminance, prevDcy);
prevDcCb = WriteBlock(cb, QuantIndex.Chrominance, prevDcCb);
prevDcCr = WriteBlock(cr, QuantIndex.Chrominance, prevDcCr);
}
}
}
private void Encode420(IPixelAccessor pixels)
{
Block b = new Block();
Block[] cb = new Block[4];
Block[] cr = new Block[4];
int prevDcy = 0, prevDcCb = 0, prevDcCr = 0;
for (int i = 0; i < 4; i++){
cb[i] = new Block();
}
for (int i = 0; i < 4; i++){
cr[i] = new Block();
}
for (int y = 0; y < pixels.Height; y += 16){
for (int x = 0; x < pixels.Width; x += 16){
for (int i = 0; i < 4; i++){
int xOff = (i & 1)*8;
int yOff = (i & 2)*4;
ToYCbCr(pixels, x + xOff, y + yOff, b, cb[i], cr[i]);
prevDcy = WriteBlock(b, QuantIndex.Luminance, prevDcy);
}
Scale16X16_8X8(b, cb);
prevDcCb = WriteBlock(b, QuantIndex.Chrominance, prevDcCb);
Scale16X16_8X8(b, cr);
prevDcCr = WriteBlock(b, QuantIndex.Chrominance, prevDcCr);
}
}
}
private static void ToYCbCr(IPixelAccessor pixels, int x, int y, Block yBlock, Block cbBlock, Block crBlock)
{
int xmax = pixels.Width - 1;
int ymax = pixels.Height - 1;
for (int j = 0; j < 8; j++){
for (int i = 0; i < 8; i++){
byte[] pixel = pixels[Math.Min(x + i, xmax), Math.Min(y + j, ymax)].ToBytes();
YCbCr2 color = Color2.FromArgb(pixel[3], pixel[0], pixel[1], pixel[2]);
int index = 8*j + i;
yBlock[index] = (int) color.Y;
cbBlock[index] = (int) color.Cb;
crBlock[index] = (int) color.Cr;
}
}
}
private static void Scale16X16_8X8(Block destination, Block[] source)
{
for (int i = 0; i < 4; i++){
int dstOff = ((i & 2) << 4) | ((i & 1) << 2);
for (int y = 0; y < 4; y++){
for (int x = 0; x < 4; x++){
int j = 16*y + 2*x;
int sum = source[i][j] + source[i][j + 1] + source[i][j + 8] + source[i][j + 9];
destination[8*y + x + dstOff] = (sum + 2)/4;
}
}
}
}
private void ProcessSos(int n)
{
if (nComp == 0){
throw new Exception("missing SOF marker");
}
if (n < 6 || 4 + (2*nComp) < n || n%2 != 0){
throw new Exception("SOS has wrong length");
}
ReadFull(tmp, 0, n);
byte lnComp = tmp[0];
if (n != 4 + (2*lnComp)){
throw new Exception("SOS length inconsistent with number of components");
}
Scan[] scan = new Scan[maxComponents];
int totalHv = 0;
for (int i = 0; i < lnComp; i++){
int cs = tmp[1 + (2*i)];
int compIndex = -1;
for (int j = 0; j < nComp; j++){
Component compv = comp[j];
if (cs == compv.c){
compIndex = j;
}
}
if (compIndex < 0){
throw new Exception("Unknown component selector");
}
scan[i].compIndex = (byte) compIndex;
for (int j = 0; j < i; j++){
if (scan[i].compIndex == scan[j].compIndex){
throw new Exception("Repeated component selector");
}
}
totalHv += comp[compIndex].h*comp[compIndex].v;
scan[i].td = (byte) (tmp[2 + (2*i)] >> 4);
if (scan[i].td > maxTh){
throw new Exception("bad Td value");
}
scan[i].ta = (byte) (tmp[2 + (2*i)] & 0x0f);
if (scan[i].ta > maxTh){
throw new Exception("bad Ta value");
}
}
if (nComp > 1 && totalHv > 10){
throw new Exception("Total sampling factors too large.");
}
int zigStart = 0;
int zigEnd = Block.blockSize - 1;
int ah = 0;
int al = 0;
if (progressive){
zigStart = tmp[1 + (2*lnComp)];
zigEnd = tmp[2 + (2*lnComp)];
ah = tmp[3 + (2*lnComp)] >> 4;
al = tmp[3 + (2*lnComp)] & 0x0f;
if ((zigStart == 0 && zigEnd != 0) || zigStart > zigEnd || Block.blockSize <= zigEnd){
throw new Exception("Bad spectral selection bounds");
}
if (zigStart != 0 && lnComp != 1){
throw new Exception("Progressive AC coefficients for more than one component");
}
if (ah != 0 && ah != al + 1){
throw new Exception("Bad successive approximation values");
}
}
int h0 = comp[0].h;
int v0 = comp[0].v;
int mxx = (width + (8*h0) - 1)/(8*h0);
int myy = (height + (8*v0) - 1)/(8*v0);
if (grayImage == null && ycbcrImage == null){
MakeImg(mxx, myy);
}
if (progressive){
for (int i = 0; i < lnComp; i++){
int compIndex = scan[i].compIndex;
if (progCoeffs[compIndex] == null){
progCoeffs[compIndex] = new Block[mxx*myy*comp[compIndex].h*comp[compIndex].v];
for (int j = 0; j < progCoeffs[compIndex].Length; j++){
progCoeffs[compIndex][j] = new Block();
}
}
}
}
bits = new BitsClass();
int mcu = 0;
byte expectedRst = JpegConstants.Markers.RST0;
Block b = new Block();
int[] dc = new int[maxComponents];
int blockCount = 0;
for (int my = 0; my < myy; my++){
for (int mx = 0; mx < mxx; mx++){
for (int i = 0; i < lnComp; i++){
int compIndex = scan[i].compIndex;
int hi = comp[compIndex].h;
int vi = comp[compIndex].v;
Block qt = quant[comp[compIndex].tq];
for (int j = 0; j < hi*vi; j++){
int bx;
int by;
if (lnComp != 1){
bx = hi*mx + j%hi;
by = vi*my + j/hi;
} else{
int q = mxx*hi;
bx = blockCount%q;
by = blockCount/q;
blockCount++;
if (bx*8 >= width || by*8 >= height){
continue;
}
}
b = progressive ? progCoeffs[compIndex][@by*mxx*hi + bx] : new Block();
if (ah != 0){
Refine(b, huff[acTable, scan[i].ta], zigStart, zigEnd, 1 << al);
} else{
int zig = zigStart;
if (zig == 0){
zig++;
byte value = DecodeHuffman(huff[dcTable, scan[i].td]);
if (value > 16){
throw new Exception("Excessive DC component");
}
int dcDelta = ReceiveExtend(value);
dc[compIndex] += dcDelta;
b[0] = dc[compIndex] << al;
}
if (zig <= zigEnd && eobRun > 0){
eobRun--;
} else{
var huffv = huff[acTable, scan[i].ta];
for (; zig <= zigEnd; zig++){
byte value = DecodeHuffman(huffv);
byte val0 = (byte) (value >> 4);
byte val1 = (byte) (value & 0x0f);
if (val1 != 0){
zig += val0;
if (zig > zigEnd){
break;
}
int ac = ReceiveExtend(val1);
b[unzig[zig]] = ac << al;
} else{
if (val0 != 0x0f){
eobRun = (ushort) (1 << val0);
if (val0 != 0){
eobRun |= (ushort) DecodeBits(val0);
}
eobRun--;
break;
}
zig += 0x0f;
}
}
}
}
if (progressive){
if (zigEnd != Block.blockSize - 1 || al != 0){
progCoeffs[compIndex][by*mxx*hi + bx] = b;
continue;
}
}
for (int zig = 0; zig < Block.blockSize; zig++){
b[unzig[zig]] *= qt[zig];
}
IDCT.Transform(b);
byte[] dst;
int offset;
int stride;
if (nComp == 1){
dst = grayImage.pixels;
stride = grayImage.stride;
offset = grayImage.offset + 8*(by*grayImage.stride + bx);
} else{
switch (compIndex){
case 0:
dst = ycbcrImage.pix_y;
stride = ycbcrImage.y_stride;
offset = ycbcrImage.y_offset + 8*(by*ycbcrImage.y_stride + bx);
break;
case 1:
dst = ycbcrImage.pix_cb;
stride = ycbcrImage.c_stride;
offset = ycbcrImage.c_offset + 8*(by*ycbcrImage.c_stride + bx);
break;
case 2:
dst = ycbcrImage.pix_cr;
stride = ycbcrImage.c_stride;
offset = ycbcrImage.c_offset + 8*(by*ycbcrImage.c_stride + bx);
break;
case 3:
throw new Exception("Too many components");
default:
throw new Exception("Too many components");
}
}
for (int y = 0; y < 8; y++){
int y8 = y*8;
int yStride = y*stride;
for (int x = 0; x < 8; x++){
int c = b[y8 + x];
if (c < -128){
c = 0;
} else if (c > 127){
c = 255;
} else{
c += 128;
}
dst[yStride + x + offset] = (byte) c;
}
}
} // for j
} // for i
mcu++;
if (ri > 0 && mcu%ri == 0 && mcu < mxx*myy){
ReadFull(tmp, 0, 2);
if (tmp[0] != 0xff || tmp[1] != expectedRst){
throw new Exception("Bad RST marker");
}
expectedRst++;
if (expectedRst == JpegConstants.Markers.RST7 + 1){
expectedRst = JpegConstants.Markers.RST0;
}
bits = new BitsClass();
dc = new int[maxComponents];
eobRun = 0;
}
} // for mx
} // for my
}
public int RefineNonZeroes(Block b, int zig, int zigEnd, int nz, int delta)
{
for (; zig <= zigEnd; zig++){
int u = unzig[zig];
if (b[u] == 0){
if (nz == 0){
break;
}
nz--;
continue;
}
bool bit = DecodeBit();
if (!bit){
continue;
}
if (b[u] >= 0){
b[u] += delta;
} else{
b[u] -= delta;
}
}
return zig;
}
private void Refine(Block b, Huffman h, int zigStart, int zigEnd, int delta)
{
if (zigStart == 0){
if (zigEnd != 0){
throw new Exception("Invalid state for zig DC component");
}
bool bit = DecodeBit();
if (bit){
b[0] |= delta;
}
return;
}
int zig = zigStart;
if (eobRun == 0){
for (; zig <= zigEnd; zig++){
bool done = false;
int z = 0;
var val = DecodeHuffman(h);
int val0 = val >> 4;
int val1 = val & 0x0f;
switch (val1){
case 0:
if (val0 != 0x0f){
eobRun = (ushort) (1 << val0);
if (val0 != 0){
uint bits = DecodeBits(val0);
eobRun |= (ushort) bits;
}
done = true;
}
break;
case 1:
z = delta;
bool bit = DecodeBit();
if (!bit){
z = -z;
}
break;
default:
throw new Exception("unexpected Huffman code");
}
if (done){
break;
}
zig = RefineNonZeroes(b, zig, zigEnd, val0, delta);
if (zig > zigEnd){
throw new Exception($"too many coefficients {zig} > {zigEnd}");
}
if (z != 0){
b[unzig[zig]] = z;
}
}
}
if (eobRun > 0){
eobRun--;
RefineNonZeroes(b, zig, zigEnd, -1, delta);
}
}