private HuffVal[] decodeHuff(int tableOffset)
{
HuffVal[] huffOut = new HuffVal[256];
int table1Len = DataUtil.getLEInt(fileData, tableOffset) * 2;
int table1Start = tableOffset + 4;
int table2Start = table1Start + table1Len;
int table3Start = table2Start + 0x48;
for (int i = 0; i < 256; ++i)
{
int bit = 1;
int a = i >> (8 - bit);
int v = DataUtil.getLEInt(fileData, table3Start + bit * 4);
while (v < a)
{
++bit;
if (bit > 8)
{
break;
}
a = i >> (8 - bit);
v = DataUtil.getLEInt(fileData, table3Start + bit * 4);
}
huffOut[i] = new HuffVal();
if (bit <= 8)
{
int val = DataUtil.getLEInt(fileData, table2Start + bit * 4);
int table1Index = a + val;
huffOut[i].val = DataUtil.getLEShort(fileData, table1Start + table1Index * 2);
huffOut[i].numBits = (short)bit;
}
}
return(huffOut);
}
private HuffVal[] decodeHuff(int tableOffset)
{
HuffVal[] huffOut = new HuffVal[256];
int table1Len = DataUtil.getLEInt(fileData, tableOffset) * 2;
int table1Start = tableOffset + 4;
int table2Start = table1Start + table1Len;
int table3Start = table2Start + 0x48;
for (int i=0; i<256; ++i){
int bit=1;
int a = i >> (8-bit);
int v = DataUtil.getLEInt(fileData, table3Start + bit*4);
while (v < a){
++bit;
if (bit > 8){
break;
}
a = i >> (8-bit);
v = DataUtil.getLEInt(fileData, table3Start + bit*4);
}
huffOut[i] = new HuffVal();
if (bit <= 8){
int val = DataUtil.getLEInt(fileData, table2Start + bit*4);
int table1Index = a + val;
huffOut[i].val = DataUtil.getLEShort(fileData, table1Start + table1Index * 2 );
huffOut[i].numBits = (short)bit;
}
}
return huffOut;
}
private void decodeBlock(int xblock, int yblock, int blockDataStart, int table0Start, WriteableBitmap image, PalEntry[] palette, HuffVal[] huffVals)
{
int tableOffset = table0Start + 0x800;
int table1Len = DataUtil.getLEInt(fileData, tableOffset) * 2;
int table1Start = tableOffset + 4;
int table2Start = table1Start + table1Len;
int table3Start = table2Start + 0x48;
int[] pix8s = new int[16*16];
int curpix8=0;
int startBit=0;
int prevPixel=0;
for (int y=0; y<16; ++y){
for (int x=0; x < 16; ++x){
int startWordIdx = startBit / 16;
int word1 = DataUtil.getLEUShort(fileData, blockDataStart + startWordIdx * 2);
int word2 = DataUtil.getLEUShort(fileData, blockDataStart + startWordIdx * 2 + 2);
// if startBit is 0, word == word1
// if startBit is 1, word is 15 bits of word1 and 1 bit of word2
int word = ((word1 << 16 | word2) >> (16 - (startBit & 0x0f))) & 0xFFFF;
int byte1 = (word >> 8) & 0xff;
HuffVal hv = huffVals[byte1];
int pixCmd;
if (hv.numBits != 0){
pixCmd = hv.val;
startBit += hv.numBits;
} else {
// Must be more than an 8 bit code
int bit=9;
int a = word >> (16-bit);
int v = DataUtil.getLEInt(fileData, table3Start + bit*4);
while (v < a){
++bit;
if (bit > 16){
throw new Exception("A decoding error occured");
}
a = word >> (16-bit);
v = DataUtil.getLEInt(fileData, table3Start + bit*4);
}
startBit += bit;
int val = DataUtil.getLEInt(fileData, table2Start + bit*4);
int table1Index = a + val;
pixCmd = DataUtil.getLEShort(fileData, table1Start + table1Index*2);
}
int pix8 = 0;
if (pixCmd < 0x100){
pix8 = pixCmd;
} else if (pixCmd < 0x105){
int backjump = backJumpTable[pixCmd - 0x100];
if ((curpix8 + backjump) >= 0){
pix8 = pix8s[curpix8 + backjump];
} else {
throw new Exception("Something went wrong");
}
} else {
int table0Index = (pixCmd - 0x105) + prevPixel * 8;
pix8 = fileData[table0Start + table0Index] & 0xFF;
}
pix8s[curpix8++] = pix8;
prevPixel = pix8 & 0xFF;
PalEntry pixel = palette[pix8 & 0xFF];
var pBackBuffer = image.BackBuffer;
int xpos = xblock * 16 + x;
int ypos = yblock * 16 + y;
var p = pBackBuffer + ypos * image.BackBufferStride + xpos * 4;
unsafe
{
*((int*)p) = pixel.argb();
}
}
}
}
private void decodeBlock(int xblock, int yblock, int blockDataStart, int table0Start, WriteableBitmap image, PalEntry[] palette, HuffVal[] huffVals)
{
int tableOffset = table0Start + 0x800;
int table1Len = DataUtil.getLEInt(fileData, tableOffset) * 2;
int table1Start = tableOffset + 4;
int table2Start = table1Start + table1Len;
int table3Start = table2Start + 0x48;
int[] pix8s = new int[16 * 16];
int curpix8 = 0;
int startBit = 0;
int prevPixel = 0;
for (int y = 0; y < 16; ++y)
{
for (int x = 0; x < 16; ++x)
{
int startWordIdx = startBit / 16;
int word1 = DataUtil.getLEUShort(fileData, blockDataStart + startWordIdx * 2);
int word2 = DataUtil.getLEUShort(fileData, blockDataStart + startWordIdx * 2 + 2);
// if startBit is 0, word == word1
// if startBit is 1, word is 15 bits of word1 and 1 bit of word2
int word = ((word1 << 16 | word2) >> (16 - (startBit & 0x0f))) & 0xFFFF;
int byte1 = (word >> 8) & 0xff;
HuffVal hv = huffVals[byte1];
int pixCmd;
if (hv.numBits != 0)
{
pixCmd = hv.val;
startBit += hv.numBits;
}
else
{
// Must be more than an 8 bit code
int bit = 9;
int a = word >> (16 - bit);
int v = DataUtil.getLEInt(fileData, table3Start + bit * 4);
while (v < a)
{
++bit;
if (bit > 16)
{
throw new Exception("A decoding error occured");
}
a = word >> (16 - bit);
v = DataUtil.getLEInt(fileData, table3Start + bit * 4);
}
startBit += bit;
int val = DataUtil.getLEInt(fileData, table2Start + bit * 4);
int table1Index = a + val;
pixCmd = DataUtil.getLEShort(fileData, table1Start + table1Index * 2);
}
int pix8 = 0;
if (pixCmd < 0x100)
{
pix8 = pixCmd;
}
else if (pixCmd < 0x105)
{
int backjump = backJumpTable[pixCmd - 0x100];
if ((curpix8 + backjump) >= 0)
{
pix8 = pix8s[curpix8 + backjump];
}
else
{
throw new Exception("Something went wrong");
}
}
else
{
int table0Index = (pixCmd - 0x105) + prevPixel * 8;
pix8 = fileData[table0Start + table0Index] & 0xFF;
}
pix8s[curpix8++] = pix8;
prevPixel = pix8 & 0xFF;
PalEntry pixel = palette[pix8 & 0xFF];
var pBackBuffer = image.BackBuffer;
int xpos = xblock * 16 + x;
int ypos = yblock * 16 + y;
var p = pBackBuffer + ypos * image.BackBufferStride + xpos * 4;
unsafe
{
*((int *)p) = pixel.argb();
}
}
}
}
