Merlin Moncure wrote:
On Dec 12, 2007 2:14 AM, Samantha Atkins <sjatkins@xxxxxxx> wrote:
This brings up a second question. How should I do byte order
conversion for 8 byte ints? I can't use hton ntoh routines as they
max out at 32 bits. Is there a better way? Also, are floating point
numbers guaranteed uniform?
If any one knows a a clean code example of binary binding of
parameters and binary extraction of results for all major types in C
against lippq that would be a very useful thing to have in the
standard docs.
We are working on a patch (not necessarily to be migrated with the
source code) to allow simplified binding of binary types to native C
types. You can see an older version here: it has examples how to read
off a lot of the types in binary. We should have a new patch in a day
or two that should demonstrate how to read the rest of the types in
binary. We also handled 64 bit ints...
the patch is here
http://archives.postgresql.org/pgsql-patches/2007-12/msg00014.php
if you are patient we can provide examples for all the basic built in
types, including possibly arrays...
merlin
p.s don't top post, but I dig Ron Paul :-)
This is from the patch merlin mentioned.
static unsigned int *swap8(void *outp, void *inp, int tonet)
{
static int n = 1;
unsigned int *in = (unsigned int *)inp;
unsigned int *out = (unsigned int *)outp;
/* swap when needed */
if(*(char *)&n == 1)
{
out[0] = (unsigned int)(tonet ? htonl(in[1]) : ntohl(in[1]));
out[1] = (unsigned int)(tonet ? htonl(in[0]) : ntohl(in[0]));
}
else
{
out[0] = in[0];
out[1] = in[1];
}
return out;
}
// example
if(PQfformat(res, field_num) == 1)
{
long long n;
swap8(&n, PQgetvalue(res, 0, 0), 0);
printf("%lld\n", n);
}
It will works with doubles as well.
andrew
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