internal int Read(IDataStream data)
{
int count = 0;
int length = data.Get16();
count += 2;
Precision = data.Get8();
count++;
DimY = data.Get16();
count += 2;
DimX = data.Get16();
count += 2;
NumComponents = data.Get8();
count++;
//components = new ComponentSpec[numComp]; // some image exceed this range...
Components = new ComponentSpec[256]; // setting to 256 -- not sure what it should be.
for (int i = 1; i <= NumComponents; i++)
{
if (count > length)
{
throw new IOException("ERROR: frame format error");
}
int c = data.Get8();
count++;
if (count >= length)
{
throw new IOException("ERROR: frame format error [c>=Lf]");
}
int temp = data.Get8();
count++;
if (Components[c] == null)
{
Components[c] = new ComponentSpec();
}
Components[c].hSamp = temp >> 4;
Components[c].vSamp = temp & 0x0F;
Components[c].quantTableSel = data.Get8();
count++;
}
if (count != length)
{
throw new IOException("ERROR: frame format error [Lf!=count]");
}
return(1);
}
internal int Read(IDataStream data)
{
int count = 0;
int length = data.Get16();
count += 2;
NumComponents = data.Get8();
count++;
components = new ScanComponent[NumComponents];
for (int i = 0; i < NumComponents; i++)
{
components[i] = new ScanComponent();
if (count > length)
{
throw new IOException("ERROR: scan header format error");
}
components[i].ScanCompSel = data.Get8();
count++;
int tempval = data.Get8();
count++;
components[i].DcTabSel = tempval >> 4;
components[i].AcTabSel = tempval & 0x0F;
}
Selection = data.Get8();
count++;
SpectralEnd = data.Get8();
count++;
int temp = data.Get8();
Ah = temp >> 4;
Al = temp & 0x0F;
count++;
if (count != length)
{
throw new IOException("ERROR: scan header format error [count!=Ns]");
}
return(1);
}
internal int Read(IDataStream data, int[] table)
{
int count = 0;
int length = data.Get16();
count += 2;
while (count < length)
{
int temp = data.Get8();
count++;
int t = temp & 0x0F;
if (t > 3)
{
throw new IOException("ERROR: Quantization table ID > 3");
}
_precision[t] = temp >> 4;
if (_precision[t] == 0)
{
_precision[t] = 8;
}
else if (_precision[t] == 1)
{
_precision[t] = 16;
}
else
{
throw new IOException("ERROR: Quantization table precision error");
}
_tq[t] = 1;
if (_precision[t] == 8)
{
for (int i = 0; i < 64; i++)
{
if (count > length)
{
throw new IOException("ERROR: Quantization table format error");
}
quantTables[t][i] = data.Get8();
count++;
}
EnhanceQuantizationTable(quantTables[t], table);
}
else
{
for (int i = 0; i < 64; i++)
{
if (count > length)
{
throw new IOException("ERROR: Quantization table format error");
}
quantTables[t][i] = data.Get16();
count += 2;
}
EnhanceQuantizationTable(quantTables[t], table);
}
}
if (count != length)
{
throw new IOException("ERROR: Quantization table error [count!=Lq]");
}
return(1);
}
internal int Read(IDataStream data, int[, ][] HuffTab)
{
int count = 0;
int length = data.Get16();
count += 2;
while (count < length)
{
int temp = data.Get8();
count++;
int t = temp & 0x0F;
if (t > 3)
{
throw new IOException("ERROR: Huffman table ID > 3");
}
int c = temp >> 4;
if (c > 2)
{
throw new IOException("ERROR: Huffman table [Table class > 2 ]");
}
_th[t] = 1;
_tc[t, c] = 1;
for (int i = 0; i < 16; i++)
{
_l[t, c][i] = data.Get8();
count++;
}
for (int i = 0; i < 16; i++)
{
for (int j = 0; j < _l[t, c][i]; j++)
{
if (count > length)
{
throw new IOException("ERROR: Huffman table format error [count>Lh]");
}
_v[t, c][i, j] = data.Get8();
count++;
}
}
}
if (count != length)
{
throw new IOException("ERROR: Huffman table format error [count!=Lf]");
}
for (int i = 0; i < 4; i++)
{
for (int j = 0; j < 2; j++)
{
if (_tc[i, j] != 0)
{
BuildHuffTable(HuffTab[i, j], _l[i, j], _v[i, j]);
}
}
}
return(1);
}