[geos-devel] GEOS SRID Patch

[Charlie Savage]

So - any comments on this.  Will people get upset if I commit it (which 
I would like to do)?

Charlie

Charlie Savage wrote:
> I've attached a patch that implements what we discussed yesterday.
> 
> More specifically:
> 
> * It updates WkbWriter to support outputting SRID values in EWKB/HEX 
> format.  This is off by default so is backwards compatible.
> 
> * Adds getter/setter methods for byte order, dimensions and include SRID 
> to WkbWriter - these are needed for the C API changes below.
> 
> * Adds new C API interfaces for WktReader, WktWriter, WkbReader, 
> WkbWriter.  These were added to the end of the *.h file and I did not 
> change any existing C apis - so this should be backwards compatible.
> 
> Here is what the new WkbWriter interface, which is the most complicated 
> one, looks like:
> 
> extern GEOSWKBWriter GEOS_DLL *GEOSWKBWriter_create();
> extern void GEOS_DLL GEOSWKBWriter_destroy(GEOSWKBWriter* writer);
> 
> extern unsigned char GEOS_DLL *GEOSWKBWriter_write(GEOSWKBWriter* 
> writer, const GEOSGeometry* g, size_t *size);
> extern unsigned char GEOS_DLL *GEOSWKBWriter_writeHEX(GEOSWKBWriter* 
> writer, const GEOSGeometry* g, size_t *size);
> 
> extern int GEOS_DLL GEOSWKBWriter_getOutputDimension(const 
> GEOSWKBWriter* writer);
> extern void GEOS_DLL GEOSWKBWriter_setOutputDimension(GEOSWKBWriter* 
> writer, int newDimension);
> 
> extern int GEOS_DLL GEOSWKBWriter_getByteOrder(const GEOSWKBWriter* 
> writer);
> extern void GEOS_DLL GEOSWKBWriter_setByteOrder(GEOSWKBWriter* writer, 
> int byteOrder);
> 
> extern char GEOS_DLL GEOSWKBWriter_getIncludeSRID(const GEOSWKBWriter* 
> writer);
> extern void GEOS_DLL GEOSWKBWriter_setIncludeSRID(GEOSWKBWriter* writer, 
> const char writeSRID);
> 
> Here is some example ruby code that uses the new api via SWIG:
> 
> writer = Geos::WktWriter.new
> writer.includes_srid = true
> writer.output_dimension = 3
> wkb = writer.write(geom)
> hex = writer.write_hex(geom)
> 
> The other readers/writers work similarly.
> 
> I think this is a better approach then the current API because:
> 
> 1.  It eliminates the need for the hacky static variables for byte order 
> and output dimensions
> 
> 2.  It gives the client more control - you can create a reader/writer 
> and reuse it instead of having a new one created every time you 
> read/write a geometry
> 
> 3.  Its more extensible.  For example, at some point we may wish that 
> the WktReader supports the EWKT format.  That would require doing this:
> 
> extern char GEOS_DLL GEOSWKTWriter_getIncludeSRID(const GEOSWKTWriter* 
> writer);
> extern void GEOS_DLL GEOSWKTWriter_setIncludeSRID(GEOSWKTWriter* writer, 
> const char writeSRID);
> 
> 
> So I think this patch meets my objectives (more client control, supports 
> outputting SRID values), Frank's objectives (get rid of static fields) 
> and Paul's (backwards compatible).
> 
> I also tested it by exposing the new API via SWIG and updating the 
> various Ruby tests I have.  So at least every new method has been 
> called/verified via a simple set of tests.
> 
> Comments?  If this looks ok, can I apply it?
> 
> Charlie
> 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: smime.p7s
Type: application/x-pkcs7-signature
Size: 3237 bytes
Desc: S/MIME Cryptographic Signature
Url : http://lists.osgeo.org/pipermail/geos-devel/attachments/20070918/f8c0b2b4/smime.bin