Merge pull request #2014 from lijun99/vrt_mmap

VRTRawRasterBand: add GetVirtualMemAuto interface to enable mmap io
OSGeo · Nov 13, 2019 · b8ece9b · b8ece9b
2 parents 54536a3 + c035018
commit b8ece9b
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Showing 2 changed files with 27 additions and 1 deletion.
diff --git a/gdal/frmts/vrt/vrtdataset.h b/gdal/frmts/vrt/vrtdataset.h
@@ -817,6 +817,11 @@ class CPL_DLL VRTRawRasterBand CPL_NON_FINAL: public VRTRasterBand
 
     void           ClearRawLink();
 
+    CPLVirtualMem *GetVirtualMemAuto( GDALRWFlag eRWFlag,
+                                      int *pnPixelSpace,
+                                      GIntBig *pnLineSpace,
+                                      char **papszOptions ) override;
+
     virtual void   GetFileList( char*** ppapszFileList, int *pnSize,
                                 int *pnMaxSize, CPLHashSet* hSetFiles ) override;
 };
@@ -1357,7 +1362,7 @@ class VRTDimension final: public GDALDimension
                                                 const CPLXMLNode* psNode);
 
     std::shared_ptr<GDALMDArray> GetIndexingVariable() const override;
-   
+
     bool SetIndexingVariable(std::shared_ptr<GDALMDArray> poIndexingVariable) override;
 
     void Serialize(CPLXMLNode* psParent) const;

diff --git a/gdal/frmts/vrt/vrtrawrasterband.cpp b/gdal/frmts/vrt/vrtrawrasterband.cpp
@@ -322,6 +322,27 @@ void VRTRawRasterBand::ClearRawLink()
     m_pszSourceFilename = nullptr;
 }
 
+/************************************************************************/
+/*                            GetVirtualMemAuto()                       */
+/************************************************************************/
+
+CPLVirtualMem * VRTRawRasterBand::GetVirtualMemAuto( GDALRWFlag eRWFlag,
+                                                     int *pnPixelSpace,
+                                                     GIntBig *pnLineSpace,
+                                                     char **papszOptions )
+
+{
+    // check the pointer to RawRasterBand
+    if( m_poRawRaster == nullptr )
+    {
+        // use the super class method
+        return VRTRasterBand::GetVirtualMemAuto(eRWFlag, pnPixelSpace, pnLineSpace, papszOptions);
+    }
+    // if available, use the RawRasterBand method (use mmap if available)
+    return m_poRawRaster->GetVirtualMemAuto(eRWFlag, pnPixelSpace, pnLineSpace, papszOptions);
+}
+
+
 /************************************************************************/
 /*                              XMLInit()                               */
 /************************************************************************/