[GRASS5] new vector2

Michel Wurtz mw at teledetection.fr
Fri Jan 5 05:05:11 EST 2001

"Eric G . Miller" wrote:
> As was mentioned, maybe it is possible to always write data in native
> format, but perform a byte swap conversion on read if necessary.  It
> would require a bitfield or such to specify endianness.  I don't know if
> this would cause more headache than it's worth, since partial
> updates/writes would also need a conversion check.  Maybe it's just
> better to choose one and live with the conversion slow down.
> > 2) It is possible to compile version 4 vector library with #define
> > NO_PORTABLE  and all vector files will be written in native format
> > instead of portable.  Speed on little endian machine is increased but
> > such non portable vector files may be not be used on big endian
> > computer then.  Somebody ever used such option?  Should be this
> > feature keept in new vector format/library? My suggestion is do not
> > support that option and be sure that all vector files in the world are
> > always portable.
> I agree with dropping it.

Another solution is always write data in native format with a flag to
specify endianness and have a program for converting from one format
to another.  This means also that we must detect if a file doesn't fit
the machine endianness, in order to to call the conversion program
inside the open function. The slow down is then limited to the first

Michel WURTZ - DIG - Maison de la télédétection
               500, rue J.F. Breton
               34093 MONTPELLIER Cedex 5

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