[fpc-pascal] Converting big-endian signed 16bits values to fpc integer

Giuliano Colla giuliano.colla at fastwebnet.it
Mon Apr 16 00:53:22 CEST 2012

Il 16/04/2012 00:42, Jonas Maebe ha scritto:
> On 16 Apr 2012, at 00:38, Giuliano Colla wrote:
>> I'm dealing with a large number of data coming from an external device.
>> They are big-endian 16 bits signed numbers, which must be converted to integer and to real to perform calculations.
>> Besides the obvious solutions of treating them as isolated bytes, multipying by 256 the highest, adding the lower, and oring wit $FFFF0000, or whatever sizeof(Integer) suggests if the result is bigger than 32767, is there a more efficient and elegant way to achieve the result?
> Call BEtoN() on them (Big Endian to Native byte order). Note that this routine is overloaded for all integer sizes>  1, and that FPC extends the size of any number<  32/64 bits (depending on the architecture) to 32/64 bits when performing almost any operation on it. It's therefore probably the safest to call it as BEtoN(smallint(value)) to ensure that the correct overload is selected.
I was sure that hidden somewhere there was a better way!
Thanks a lot


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