[postgis-devel] Re: dbfopen numeric fields handling broken ?

[strk]

On Wed, May 12, 2004 at 09:56:41AM -0400, Frank Warmerdam wrote:
> strk wrote:
> > On Wed, May 12, 2004 at 08:27:38AM -0400, Frank Warmerdam wrote:
> > 
> >>strk wrote:
> >>
> >>>Hello again Frank.
> >>>I got a .dbf containing a Numeric field with lenght=12 and
> >>>decimal places=0.
> >>>DBFGetFieldInfo() tells me it's a FTInteger (because of 0 decimals).
> >>>DBFReadIntegerAttribute() casts the value to an integer, but this
> >>>conversion seems to be inadeguate, since I get always -2147483648.
> >>>Values goes from 10010001000 to 51580035000 (viewing with dbview),
> >>>so it does not seem to be a corrupted dataset.
> >>>
> >>>dbfopen.c is Revision 1.52  2003/07/08 15:20:03  warmerda.
> >>>
> >>>Any hint on how to fix this ?
> >>
> >>Strk,
> >>
> >>Can you provide the .dbf file?  I have heard other reports of problems with
> >>large integer values and I would like to try and resolve the issue.
> > 
> > 
> > I've checked and fixed the bug already. 
> > What is needed is have DBFReadIntegerAttribute return an int with 64bits,
> > or directly return a double if an int64 is not enough to contain the 
> > maximum lenght for a dbf field of type N with no digits.
> > For sure returning 'int' (signed) does not allow numbers higher 
> > then 2147483647 or -2147483648, whih is 9 digits guaranteed. No more.
> 
> Strk,
> 
> Can you provide a sample dbf file demonstrating the problem?

Sorry, but I can't. 
I dunno how.
I tried exporting a postgis table, but it seems that the same
problem with Reading is there when Writing, probably
DBFWriteIntegerAttribute...
If you have tools to produce a dbf should be really straightforward
to reproduce the bug: create a field of type N with 12 digits and 0
decimal places. Put the value 620570012000 in the field.
Read it.
Write it in a new dbf.
Check the new dbf.

I've included postgis-devel in the recipient list since this bug
makes both postgis loader and dumper bogus as well.. 

--strk;

> 
> Best regards,
> -- 
> ---------------------------------------+--------------------------------------
> I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | Geospatial Programmer for Rent