bool Lerc::Convert(const CntZImage& zImg, T* arr, BitMask* pBitMask) const
{
if (!arr || !zImg.getSize())
return false;
const bool fltPnt = (typeid(*arr) == typeid(double)) || (typeid(*arr) == typeid(float));
int h = zImg.getHeight();
int w = zImg.getWidth();
if (pBitMask)
{
pBitMask->SetSize(w, h);
pBitMask->SetAllValid();
}
const CntZ* srcPtr = zImg.getData();
T* dstPtr = arr;
int num = w * h;
for (int k = 0; k < num; k++)
{
if (srcPtr->cnt > 0)
*dstPtr = fltPnt ? (T)srcPtr->z : (T)floor(srcPtr->z + 0.5);
else if (pBitMask)
pBitMask->SetInvalid(k);
srcPtr++;
dstPtr++;
}
return true;
}
bool Lerc::DecodeTempl(T* pData, // outgoing data bands
const Byte* pLercBlob,
size_t numBytesBlob,
int nCols, int nRows, int nBands,
BitMask* pBitMask) const // gets filled if not 0, even if all valid
{
if (!pLercBlob || !pData)
return false;
const Byte* pByte = pLercBlob;
Byte* pByte1 = const_cast<Byte*>(pLercBlob);
Lerc2 lerc2;
CntZImage zImg;
for (int iBand = 0; iBand < nBands; iBand++)
{
// first try Lerc2
unsigned int numBytesHeader = lerc2.ComputeNumBytesHeader();
Lerc2::HeaderInfo hdInfo;
if (((size_t)(pByte - pLercBlob) + numBytesHeader <= numBytesBlob) && lerc2.GetHeaderInfo(pByte, hdInfo))
{
if (hdInfo.nCols != nCols || hdInfo.nRows != nRows)
return false;
if ((pByte - pLercBlob) + (size_t)hdInfo.blobSize > numBytesBlob)
return false;
// init bitMask
if (pBitMask && iBand == 0)
pBitMask->SetSize(nCols, nRows);
T* arr = pData + nCols * nRows * iBand;
if (!lerc2.Decode(&pByte, arr, (pBitMask && iBand == 0) ? pBitMask->Bits() : 0))
return false;
}
else // then try Lerc1
{
unsigned int numBytesHeader = CntZImage::computeNumBytesNeededToReadHeader();
if ((size_t)(pByte - pLercBlob) + numBytesHeader > numBytesBlob)
return false;
bool onlyZPart = iBand > 0;
if (!zImg.read(&pByte1, 1e12, false, onlyZPart))
return false;
if (zImg.getWidth() != nCols || zImg.getHeight() != nRows)
return false;
T* arr = pData + nCols * nRows * iBand;
if (!Convert(zImg, arr, pBitMask))
return false;
}
} // iBand
return true;
}
// Unload a zImg into a buffer
template <typename T> void CntZImgUFill(CntZImage &zImg, T *dst, const ILImage &img)
{
int h = static_cast<int>(zImg.getHeight());
int w = static_cast<int>(zImg.getWidth());
T *ptr = dst;
T ndv = (T)(img.NoDataValue);
// Use 0 if nodata is not defined
if (!img.hasNoData) ndv = 0;
for (int i = 0; i < h; i++)
for (int j = 0; j < w; j++)
*ptr++ = (zImg(i, j).cnt == 0) ? ndv : (T)(zImg(i, j).z);
}
