From: | Merlin Moncure <mmoncure(at)gmail(dot)com> |
---|---|
To: | Adrian Schreyer <ams214(at)cam(dot)ac(dot)uk> |
Cc: | pgsql-general(at)postgresql(dot)org |
Subject: | Re: Best way to construct PostgreSQL ArrayType (_int4) from C int array |
Date: | 2011-04-27 13:49:34 |
Message-ID: | BANLkTi=8mc6+5t+BYXkaMNhp6miChNS=7Q@mail.gmail.com |
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Lists: | pgsql-general |
On Wed, Apr 27, 2011 at 6:02 AM, Adrian Schreyer <ams214(at)cam(dot)ac(dot)uk> wrote:
> At the moment I am using the following code to construct a PostgreSQL
> array from a C array in my C extension but I am not so sure if this is
> really the best solution:
>
> const int *data = array.data(); // C array
> Datum *d = (Datum *) palloc(sizeof(Datum) * size);
>
> for (int i = 0; i < size; i++) d[i] = Int32GetDatum(data[i]);
>
> ArrayType *a = construct_array(d, size, INT4OID, sizeof(int4), true, 'i');
>
> Is this okay or is there a better solution (existing function in the
> PostgreSQL source for example)?
That's pretty much the best way AFAIK. Int32GetDatum doesn't do
anything fancy -- it's just a 32 bit mask/assignment. constructing
the array at once is going to be a lot better than incrementally
creating it. Do you expect the arrays to be large, say bigger than
10k elements?
merlin
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