static CPLErr DecompressLERC(buf_mgr &dst, buf_mgr &src, const ILImage &img)
{
CntZImage zImg;
Byte *ptr = (Byte *)src.buffer;
if (!zImg.read(&ptr, 1e12))
{
CPLError(CE_Failure,CPLE_AppDefined,"MRF: Error during LERC decompression");
return CE_Failure;
}
// Unpack from zImg to dst buffer, calling the right type
#define UFILL(T) CntZImgUFill(zImg, (T *)(dst.buffer), img)
switch (img.dt) {
case GDT_Byte: UFILL(GByte); break;
case GDT_UInt16: UFILL(GUInt16); break;
case GDT_Int16: UFILL(GInt16); break;
case GDT_Int32: UFILL(GInt32); break;
case GDT_UInt32: UFILL(GUInt32); break;
case GDT_Float32: UFILL(float); break;
case GDT_Float64: UFILL(double); break;
default: break;
}
#undef UFILL
return CE_None;
}
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;
}
// LERC 1 compression
static CPLErr CompressLERC(buf_mgr &dst, buf_mgr &src, const ILImage &img, double precision)
{
CntZImage zImg;
// Fill data into zImg
#define FILL(T) CntZImgFill(zImg, (T *)(src.buffer), img)
switch (img.dt) {
case GDT_Byte: FILL(GByte); break;
case GDT_UInt16: FILL(GUInt16); break;
case GDT_Int16: FILL(GInt16); break;
case GDT_Int32: FILL(GInt32); break;
case GDT_UInt32: FILL(GUInt32); break;
case GDT_Float32: FILL(float); break;
case GDT_Float64: FILL(double); break;
default: break;
}
#undef FILL
Byte *ptr = (Byte *)dst.buffer;
// if it can't compress in output buffer it will crash
if (!zImg.write(&ptr, precision)) {
CPLError(CE_Failure,CPLE_AppDefined,"MRF: Error during LERC compression");
return CE_Failure;
}
// write changes the value of the pointer, we can find the size by testing how far it moved
dst.size = ptr - (Byte *)dst.buffer;
CPLDebug("MRF_LERC","LERC Compressed to %d\n", (int)dst.size);
return CE_None;
}
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);
}
unsigned int CntZImage::computeNumBytesNeededToWriteVoidImage()
{
unsigned int cnt = 0;
CntZImage zImg;
cnt += (unsigned int)zImg.getTypeString().length(); // "CntZImage ", 10 bytes
cnt += 2 * sizeof(int);
cnt += 2 * sizeof(int);
cnt += 1 * sizeof(double);
// cnt part
cnt += 3 * sizeof(int);
cnt += sizeof(float);
// z part
cnt += 3 * sizeof(int);
cnt += sizeof(float);
cnt += 1;
return cnt;
}
// Load a buffer into a zImg
template <typename T> void CntZImgFill(CntZImage &zImg, T *src, const ILImage &img)
{
int w = img.pagesize.x;
int h = img.pagesize.y;
zImg.resize(w, h);
T *ptr = src;
// No data value
float ndv = float(img.NoDataValue);
if (!img.hasNoData) ndv = 0;
for (int i = 0; i < h; i++)
for (int j = 0; j < w; j++) {
zImg(i, j).z = float(*ptr++);
zImg(i, j).cnt = !CPLIsEqual(zImg(i, j).z, ndv);
}
return;
}
bool Lerc::GetLercInfo(const Byte* pLercBlob, size_t numBytesBlob, struct LercInfo& lercInfo) const
{
lercInfo.RawInit();
// first try Lerc2
Lerc2 lerc2;
unsigned int numBytesHeader = lerc2.ComputeNumBytesHeader();
struct Lerc2::HeaderInfo lerc2Info;
if (numBytesHeader <= numBytesBlob && lerc2.GetHeaderInfo(pLercBlob, lerc2Info))
{
lercInfo.version = lerc2Info.version;
lercInfo.nCols = lerc2Info.nCols;
lercInfo.nRows = lerc2Info.nRows;
lercInfo.numValidPixel = lerc2Info.numValidPixel;
lercInfo.nBands = 1;
lercInfo.blobSize = lerc2Info.blobSize;
lercInfo.dt = (DataType)lerc2Info.dt;
lercInfo.zMin = lerc2Info.zMin;
lercInfo.zMax = lerc2Info.zMax;
lercInfo.maxZError = lerc2Info.maxZError;
if (lercInfo.blobSize > (int)numBytesBlob) // truncated blob, we won't be able to read this band
return false;
while (lercInfo.blobSize + numBytesHeader < numBytesBlob) // means there could be another band
{
struct Lerc2::HeaderInfo hdInfo;
if (!lerc2.GetHeaderInfo(pLercBlob + lercInfo.blobSize, hdInfo))
return true; // no other band, we are done
if (hdInfo.nCols != lercInfo.nCols
|| hdInfo.nRows != lercInfo.nRows
|| hdInfo.numValidPixel != lercInfo.numValidPixel
|| (int)hdInfo.dt != (int)lercInfo.dt
|| hdInfo.maxZError != lercInfo.maxZError)
{
return false;
}
lercInfo.blobSize += hdInfo.blobSize;
if (lercInfo.blobSize > (int)numBytesBlob) // truncated blob, we won't be able to read this band
return false;
lercInfo.nBands++;
lercInfo.zMin = min(lercInfo.zMin, hdInfo.zMin);
lercInfo.zMax = max(lercInfo.zMax, hdInfo.zMax);
}
return true;
}
// then try Lerc1
numBytesHeader = CntZImage::computeNumBytesNeededToReadHeader();
Byte* pByte = const_cast<Byte*>(pLercBlob);
CntZImage cntZImg;
if (numBytesHeader <= numBytesBlob && cntZImg.read(&pByte, 1e12, true)) // read just the header
{
size_t nBytesRead = pByte - pLercBlob;
size_t nBytesNeeded = 10 + 4 * sizeof(int) + 1 * sizeof(double);
if (nBytesRead < nBytesNeeded)
return false;
Byte* ptr = const_cast<Byte*>(pLercBlob);
ptr += 10 + 2 * sizeof(int);
int height = *((const int*)ptr); ptr += sizeof(int);
int width = *((const int*)ptr); ptr += sizeof(int);
double maxZErrorInFile = *((const double*)ptr);
if (height > 20000 || width > 20000) // guard against bogus numbers
return false;
lercInfo.nCols = width;
lercInfo.nRows = height;
lercInfo.dt = Lerc::DT_Float;
lercInfo.maxZError = maxZErrorInFile;
Byte* pByte = const_cast<Byte*>(pLercBlob);
bool onlyZPart = false;
while (lercInfo.blobSize + numBytesHeader < numBytesBlob) // means there could be another band
{
if (!cntZImg.read(&pByte, 1e12, false, onlyZPart))
return (lercInfo.nBands > 0); // no other band, we are done
onlyZPart = true;
lercInfo.nBands++;
lercInfo.blobSize = (int)(pByte - pLercBlob);
// now that we have decoded it, we can go the extra mile and collect some extra info
int numValidPixels = 0;
float zMin = FLT_MAX;
float zMax = -FLT_MAX;
for (int i = 0; i < height; i++)
{
for (int j = 0; j < width; j++)
if (cntZImg(i, j).cnt > 0)
{
numValidPixels++;
float z = cntZImg(i, j).z;
zMax = max(zMax, z);
zMin = min(zMin, z);
}
}
lercInfo.numValidPixel = numValidPixels;
lercInfo.zMin = min(lercInfo.zMin, zMin);
lercInfo.zMax = max(lercInfo.zMax, zMax);
}
return true;
}
return false;
}
