Double call to tcmdbiternext when iterating is odd

[gavin-norman-sociomantic]

https://github.com/sociomantic-tsunami/dhtnode/blob/master/src/dhtnode/storage/StorageEngine.d#L625-L628

It seems this is necessary, in the current structure, but I wonder if it could be refactored to not need to do this.

[gavin-norman-sociomantic]

Weird.

unittest
{
    auto db = tcmdbnew();
    const num = 1_000;
    auto value = "whatever";
    for ( hash_t i = 0; i < num; i++ )
        tcmdbput(db, &i, cast(int)i.sizeof, value.ptr, cast(int)value.length);

    hash_t last_key = 0;
    int len;

    while ( true )
    {
        tcmdbiterinit2(db, &last_key, cast(int)last_key.sizeof);
        if ( auto key_ = cast(hash_t*)tcmdbiternext(db, &len) )
        {
            if ( auto key_ = cast(hash_t*)tcmdbiternext(db, &len) )
            {
                Stdout.formatln("{}", *key_);
                last_key = *key_;
            }
            else break;
        }
    }
}

[gavin-norman-sociomantic]

It seems that tcmdbiterinit2 initialises the iterator before the first element. Then calling tcmdbiternext once puts the iterator at the start record, and calling it again moves it on to the next record.