#10 ResetStreamPos causes SegFault if called after Read.

[Rene Lindsay]

CPGFImage.ResetStreamPos() causes a Segmentation Fault error if called after CPGFImage.Read(...)
If I try to Read more than one ROI from an open PGFImage, the second Read fails, because the first Read left the stream in the wrong position. It looks like the ResetSreamPos function was intended to fix this, but currently it crashes too. It seems, after the first Read, CDecoder.m_stream is pointing at an invalid memory location. My current workaround is to close and re-open the PGF file after each Read call.

[Christoph Stamm]

Hello Rene

Thank you for message. There is a simple solution for your problem: just
delete in PGFimage.cpp the last line in the second Read procedure (probably
line 561). In this line the decoder is automatically closed after reading.
While this automatic closing might be useful in non ROI reads, in ROI read
it is disruptive. After deleting this line you can read several ROIs after
each other:

pgf.Open(...)
pgf.Read(rect1);
pgf.ResetStreamPos();
pgf.Read(rect2);
pgf.Close();

void CPGFImage::Read(PGFRect& rect, int level /= 0/, CallbackPtr cb /=
nullptr/, void data /=nullptr*/

) {

...

// automatically closing: should be deleted

//if (m_currentLevel == 0) Close();
}

Chris

Quoting Rene Lindsay rjklindsay@users.sf.net:

---

[BUGS:#10][1] RESETSTREAMPOS CAUSES SEGFAULT IF CALLED AFTER READ.

STATUS: unread
GROUP: v1.0 (example)
CREATED: Tue May 19, 2015 12:46 PM UTC by Rene Lindsay
LAST UPDATED: Tue May 19, 2015 12:46 PM UTC
OWNER: nobody

CPGFImage.ResetStreamPos() causes a Segmentation Fault error if
called after CPGFImage.Read(...)
If I try to Read more than one ROI from an open PGFImage, the second
Read fails, because the first Read left the stream in the wrong
position. It looks like the ResetSreamPos function was intended to fix
this, but currently it crashes too. It seems, after the first Read,
CDecoder.m_stream is pointing at an invalid memory location. My current
workaround is to close and re-open the PGF file after each Read call.

---

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[1] http://sourceforge.net/p/libpgf/bugs/10