Hi all,
it took me a long time to build Podofo on Sun Solaris using the native Sun
Studio compiler.
For several reasons I could not use gcc, where everything worked fine.
With Sun Studio I ran into SIGSEGV crash (helloworld example).
As helloword sample runs fine on other machines and compilers I first
blamed Sun Studio for the crash.
But after some investigations, I think, that the problem is inside Podofo.
The problem is inside PdfVariant,
the member Variable m_Data.pData is of type PdfDataType* .
PdfDataType is an interface for real datatype classes, such as PdfArray.
Any real datatype class has multiple inheritance (I like Java!),.
PdfArray is derived from vector and PdfDataType.
In PdfVariant.cpp , operator=, m_Data.pData is assigned as
case ePdfDataType_Array:
{
if( rhs.m_Data.pData )
m_Data.pData = new PdfArray(
*(static_cast<PdfArray*>(rhs.m_Data.pData)) );
break;
}
As pData is of type PdfDataType, a pointer to the PdfDataType part of the
PdfArray is assigned.
In the debugger, if the code is slightly changed
PdfArray pNew = new PdfArray(
*(static_cast<PdfArray*>(rhs.m_Data.pData)) );
m_Data.pData = pNew;
Under dbx you see: m_Data.pData is NOT equal pNew, but pNew + (offset
PdfDataType in PdfArray).
Later, going back from m_Data.pData to PdfArray in PdfVariant.h,
a reinterpret_cast is used and the pointer is unchanged in assigment.
PdfArray & PdfVariant::GetArray_NoDL()
{
// Test against eDataType directly not GetDataType() since
// we don't want to trigger a delayed load (and if required one has
// already been triggered).
if( m_eDataType != ePdfDataType_Array )
{
PODOFO_RAISE_ERROR( ePdfError_InvalidDataType );
}
return *(reinterpret_cast<PdfArray* const>(m_Data.pData));
}
The reinterpret_cast is causing the crash as pData points to to the
PdfDataype part, not to PdfArray.
If the vector part of the PdfArray is accessed, the crash occurs.
My suggestion is to just remove the reinterpret_cast, so that assignment
and back assignment are symmetric.
After replacing the reinterpret_cast (on severall occurrences) in
PdfVariant.h, for example
// return *(reinterpret_cast<PdfArray* const>(m_Data.pData));
return *(PdfArray*)m_Data.pData;
everything worked well, on Sun Studio compiler and several other
platforms.
Why did the problem not occur in other environments?
Probably because the class layout is different, so that the PdfDatatype
part in compound objects comes
always first (offset 0).
Then, the reinterpret_cast does no harm.
friendly regards
Hartmut Haas
TONBELLER AG
Werner-von-Siemens-Str. 2
D-64625 Bensheim
Germany
www.tonbeller.com
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