#!/usr/bin/perl

# Usage:
#
#   ./lmdb.pl create dbfile <dictionary
#   ./lmdb.pl bench dbfile
#   ./lmdb.pl extract dbfile >dictionary

use strict;
use warnings;
use v5.10;
use LMDB_File ':flags', ':cursor_op';

my($cmd, $dbfile) = @ARGV;
my($env, $txn, $dbi);

sub db {
    my $wr = shift;
    $env = LMDB::Env->new($dbfile, { mapsize => 1<<36, maxdbs => 1, flags => MDB_NOSUBDIR|($wr?0:MDB_RDONLY) });
    $txn = $env->BeginTxn();
    $dbi = $txn->open('db', $wr ? MDB_CREATE : undef);
}

sub encode {
    db 1;
    while(<STDIN>) {
        chomp;
        $txn->put($dbi => $_, '') if length($_) && length($_) < 510;
    }
    $txn->commit;
}


sub bench {
    db;
    my $lookup = sub { eval { $txn->get($dbi => $_[0], my $d); 1 } };

    use Benchmark 'timethis', ':hireswallclock';
    sub rstr { state $s=['a'..'z','A'..'Z','0'..'9','!','@','#']; join '', map $s->[rand @$s], 1..5 }
    srand 0;
    timethis 200000, sub { $lookup->(rstr()) }, 'lmdb';
}


sub extract {
    db;
    my $db = LMDB_File->new($txn, $dbi);
    my $cur = $db->Cursor();
    eval {
        my($key, $value);
        $cur->get($key, $value, MDB_FIRST);
        while(1) {
            print "$key\n";
            $cur->get($key, $value, MDB_NEXT);
        }
    }
}

encode if $cmd eq 'create';
bench if $cmd eq 'bench';
extract if $cmd eq 'extract';