Awesome, thank you! I was a bit lost - learnt a lot from exploring this
though.
Cheers, Mike
On Mon, Dec 4, 2023 at 12:11 AM Even Rouault <even.roua...@spatialys.com>
wrote:
> Hi Michael,
>
> It was most missing a "break;" statement when the subdataset of interest
> has been found to exit the loop. Without the break, the loop will
> continue to read papszSubdatasets[] which has been invalidated by the
> poSrcDS->ReleaseRef(). Ah, memory unsafe languages :-). You also had a
> few memory leaks.
>
> Fixed version:
>
> #include "gdal.h"
> #include "gdal_priv.h"
> #include <iostream>
> int main(int argc, char **argv) {
> GDALAllRegister();
>
> auto poSrcDS =
> GDALDataset::Open(argv[1], GDAL_OF_RASTER, nullptr, nullptr, nullptr);
> if (poSrcDS == nullptr)
> {
> return 0;
> }
> char **papszSubdatasets = poSrcDS->GetMetadata("SUBDATASETS");
> int nSubdatasets = CSLCount(papszSubdatasets);
> if (nSubdatasets > 0)
> {
> for (int j = 0; j < nSubdatasets; j += 2)
> {
> char* pszSubdatasetSource = CPLStrdup(strstr(papszSubdatasets[j],
> "=") + 1);
> GDALSubdatasetInfoH info =
> GDALGetSubdatasetInfo(pszSubdatasetSource);
> char* component = info ?
> GDALSubdatasetInfoGetSubdatasetComponent(info) : NULL;
> const bool bFound = component && EQUAL(argv[2], component);
> CPLFree(component);
> GDALDestroySubdatasetInfo(info);
> if ( bFound) {
> std::cout << pszSubdatasetSource << "\n";
> poSrcDS->ReleaseRef();
> poSrcDS = GDALDataset::Open(pszSubdatasetSource,
> GDAL_OF_RASTER, nullptr, nullptr, nullptr);
> CPLFree(pszSubdatasetSource);
> break;
> }
> else {
> CPLFree(pszSubdatasetSource);
> }
> }
> }
>
> poSrcDS->ReleaseRef();
> return 1;
> }
>
> Even
>
>
> Le 03/12/2023 à 05:10, Michael Sumner via gdal-dev a écrit :
> > #include "gdal.h"
> > #include "gdal_priv.h"
> > #include <iostream>
> > int main(int argc, char **argv) {
> > GDALAllRegister();
> >
> > auto poSrcDS =
> > GDALDataset::Open(argv[1], GDAL_OF_RASTER, nullptr, nullptr,
> nullptr);
> > if (poSrcDS == nullptr)
> > {
> > return 0;
> > }
> > char **papszSubdatasets = poSrcDS->GetMetadata("SUBDATASETS");
> > int nSubdatasets = CSLCount(papszSubdatasets);
> > char *pszSubdatasetSource = nullptr;
> > if (nSubdatasets > 0)
> > {
> > for (int j = 0; j < nSubdatasets; j += 2)
> > {
> > pszSubdatasetSource = CPLStrdup(strstr(papszSubdatasets[j], "=")
> > + 1);
> > GDALSubdatasetInfoH info =
> > GDALGetSubdatasetInfo(pszSubdatasetSource);
> > if ( EQUAL(argv[2],
> > GDALSubdatasetInfoGetSubdatasetComponent(info))) {
> > std::cout << pszSubdatasetSource << "\n";
> > poSrcDS->ReleaseRef();
> > poSrcDS = GDALDataset::Open(pszSubdatasetSource,
> > GDAL_OF_RASTER, nullptr, nullptr, nullptr);
> > CPLFree(pszSubdatasetSource);
> > GDALDestroySubdatasetInfo(info);
> >
> > }
> > }
> > }
> >
> > poSrcDS->ReleaseRef();
> > return 1;
> > }
>
> --
> http://www.spatialys.com
> My software is free, but my time generally not.
>
>
--
Michael Sumner
Software and Database Engineer
Australian Antarctic Division
Hobart, Australia
e-mail: mdsum...@gmail.com
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