Re: pg_dump and large files - is this a problem?

Philip Warner <pjw(at)rhyme(dot)com(dot)au> writes:
> It might be good if someone who knows a little more than me about
> endianness etc has a look at the patch - specifically this bit of code:

> #if __BYTE_ORDER == __LITTLE_ENDIAN

Well, the main problem with that is there's no such symbol as
__BYTE_ORDER ...

I'd prefer not to introduce one, either, if we can possibly avoid it.
I know that we have BYTE_ORDER defined in the port header files, but
I think it's quite untrustworthy, since there is no other place in the
main distribution that uses it anymore (AFAICS only contrib/pgcrypto
uses it at all).

The easiest way to write and reassemble an arithmetic value in a
platform-independent order is via shifting. For instance,

// write, LSB first
for (i = 0; i < sizeof(off_t); i++)
{
writebyte(val & 0xFF);
val >>= 8;
}

// read, LSB first
val = 0;
shift = 0;
for (i = 0; i < sizeof(off_t); i++)
{
val |= (readbyte() << shift);
shift += 8;
}

(This assumes readbyte delivers an unsigned byte, else you might need to
mask it with 0xFF before shifting.)

regards, tom lane