Well, that depends on how you set up your map. You could instead make the
key a pointer to the protobuf field, and define your comparator so that it
dereferences the pointer. Of course you need to make sure that the pointer
is actually valid: if you mutate the field you may invalidate the pointer.
If you're concerned about that, another approach would be to make your key
type a pointer to the entire protobuf value, and have the comparator look at
the field. When doing lookups in the map, you will need to construct a dummy
protobuf to use as the lookup key.
On Tue, Nov 16, 2010 at 9:49 PM, Ma Jin <maxu...@gmail.com> wrote:
> I try to use the pb to store a group of record with the same schema.
> I wonder to know whether the key of the properties would be copied for
> every record like map<key, value>.
> if like this, it seems to a waste of memory.
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