[geos-devel] Re: [GEOS] #202: Undefined behavior in Coordinate::hashCode

[GEOS]

#202: Undefined behavior in Coordinate::hashCode
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 Reporter:  mloskot                 |        Owner:  geos-devel at lists.osgeo.org
     Type:  defect                  |       Status:  new                       
 Priority:  major                   |    Milestone:                            
Component:  Core                    |      Version:  svn-trunk                 
 Severity:  Significant             |   Resolution:                            
 Keywords:  coordinate hash double  |  
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Comment (by bmharper):

 Mateusz - you mentioned that this violates aliasing rules:

 unsigned int HashDouble( double d )
 {
  unsigned int* i = (unsigned int*) &d;
  return i[0] ^ i[1];
 }

 Can you explain further, or point me to the relevant C/++ docs?

 Thanks,
 Ben

 ps-- Your code references &x. Should this not be &d?

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Ticket URL: <http://trac.osgeo.org/geos/ticket/202#comment:1>
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GEOS (Geometry Engine - Open Source) is a C++ port of the Java Topology Suite (JTS).