0028887: TKJT - add option to cache file content

Added new auxiliary class Standard_ArrayStreamBuffer implementing
std::streambuf interface for defining std::istream from allocated memory.

src/QABugs/QABugs_20.cxx

@@ -59,6 +59,8 @@
 #include <HLRBRep_PolyHLRToShape.hxx>
 #include <HLRBRep_PolyAlgo.hxx>
 
+#include <limits>
+
 //=======================================================================
 //function : SurfaceGenOCC26675_1 
 //purpose  : Generates a surface for intersect (in corresponding
@@ -2340,6 +2342,99 @@ static Standard_Integer OCC28829 (Draw_Interpretor&, Standard_Integer, const cha
   return 0;
 }
 
+#include <NCollection_Buffer.hxx>
+#include <DDocStd_DrawDocument.hxx>
+#include <OSD_OpenFile.hxx>
+#include <Standard_ArrayStreamBuffer.hxx>
+#include <TDataStd_Name.hxx>
+#include <TDocStd_Application.hxx>
+
+#ifdef max
+  #undef max
+#endif
+
+static Standard_Integer OCC28887 (Draw_Interpretor&, Standard_Integer theNbArgs, const char** theArgVec)
+{
+  if (theNbArgs < 3)
+  {
+    std::cout << "Syntax error: wrong number of arguments!\n";
+    return 1;
+  }
+
+  const TCollection_AsciiString aFilePath (theArgVec[1]);
+  const TCollection_AsciiString aName     (theArgVec[2]);
+  Handle(NCollection_Buffer) aBuffer;
+  {
+    std::ifstream aFile;
+    OSD_OpenStream (aFile, aFilePath.ToCString(), std::ios::binary | std::ios::in);
+    if (!aFile.is_open())
+    {
+      std::cout << "Error: input file '" << aFilePath << "' cannot be read\n";
+      return 1;
+    }
+    aFile.seekg (0, std::ios_base::end);
+    const int64_t aFileLength = int64_t (aFile.tellg());
+    if (aFileLength > int64_t (std::numeric_limits<ptrdiff_t>::max())
+     || aFileLength < 1)
+    {
+      std::cout << "Error: input file '" << aFilePath << "' is too large\n";
+      return 1;
+    }
+    aFile.seekg (0, std::ios_base::beg);
+
+    aBuffer = new NCollection_Buffer (NCollection_BaseAllocator::CommonBaseAllocator());
+    if (!aBuffer->Allocate (size_t(aFileLength)))
+    {
+      std::cout << "Error: memory allocation (" << aFileLength << ") has failed\n";
+      return 1;
+    }
+
+    aFile.read ((char* )aBuffer->ChangeData(), aBuffer->Size());
+    if (!aFile.good())
+    {
+      std::cout << "Error: input file '" << aFilePath << "' reading failure\n";
+      return 1;
+    }
+  }
+
+  Standard_ArrayStreamBuffer aStreamBuffer ((const char* )aBuffer->ChangeData(), aBuffer->Size());
+  std::istream aStream (&aStreamBuffer);
+  // just play with seeking
+  aStream.seekg (0, std::ios_base::end);
+  aStream.seekg (0, std::ios_base::beg);
+  if (aFilePath.EndsWith (".brep")
+   || aFilePath.EndsWith (".rle"))
+  {
+    TopoDS_Shape aShape;
+    BRep_Builder aBuilder;
+    BRepTools::Read (aShape, aStream, aBuilder);
+    DBRep::Set (aName.ToCString(), aShape);
+  }
+  else
+  {
+    Handle(TDocStd_Document) aDoc;
+    Handle(TDocStd_Application) anApp = DDocStd::GetApplication();
+    Standard_CString aNameVar = aName.ToCString();
+    if (DDocStd::GetDocument (aNameVar, aDoc, Standard_False))
+    {
+      std::cout << "Error: document with name " << aName << " already exists\n";
+      return 1;
+    }
+
+    if (anApp->Open (aStream, aDoc) != PCDM_RS_OK)
+    {
+      std::cout << "Error: cannot open XDE document\n";
+      return 1;
+    }
+
+    Handle(DDocStd_DrawDocument) aDrawDoc = new DDocStd_DrawDocument (aDoc);
+    TDataStd_Name::Set (aDoc->GetData()->Root(), aName.ToCString());
+    Draw::Set (aName.ToCString(), aDrawDoc);
+  }
+
+  return 0;
+}
+
 void QABugs::Commands_20(Draw_Interpretor& theCommands) {
   const char *group = "QABugs";
 
@@ -2363,6 +2458,10 @@ void QABugs::Commands_20(Draw_Interpretor& theCommands) {
   theCommands.Add("OCC28594", "OCC28594", __FILE__, OCC28594, group);
   theCommands.Add("OCC28784", "OCC28784 result shape", __FILE__, OCC28784, group);
   theCommands.Add("OCC28829", "OCC28829: perform invalid FPE operation", __FILE__, OCC28829, group);
+  theCommands.Add("OCC28887",
+                  "OCC28887 filePath result"
+                  "\n\t\t: Check interface for reading BRep from memory.",
+                  __FILE__, OCC28887, group);
 
   return;
 }