Changeset 33620 for lang/perl/DBIx-CouchLike/trunk/lib/DBIx/CouchLike/IdGenerator.pm

Timestamp:

05/27/09 16:12:51 (4 years ago)

Author:

fujiwara

Message:

id generator を変更

Files:

• lang/perl/DBIx-CouchLike/trunk/lib/DBIx/CouchLike/IdGenerator.pm (modified) (1 diff)

lang/perl/DBIx-CouchLike/trunk/lib/DBIx/CouchLike/IdGenerator.pm

@@ -1 +1 @@
 package DBIx::CouchLike::IdGenerator;
+# original code from Data::YUID::Generator
+
 use strict;
 use warnings;
-use Digest::SHA qw/ sha1_hex /;
-use base qw/ Class::Accessor::Fast /;
+use Math::BigInt try => 'GMP';
+
+no warnings qw(deprecated); # for fields
+
+use vars qw{$VERSION};
+$VERSION = "0.02";
+
+use fields qw(host_id start_time current_time min_id max_id ids);
+
+use constant EPOCH_OFFSET => 946684800; # Sat, Jan 1 2000 00:00 GMT
+
+use constant HOST_ID_BITS => 16;
+use constant TIME_BITS => 36;
+use constant SERIAL_BITS => 64 - HOST_ID_BITS - TIME_BITS;
+
+use constant TIME_SHIFT => HOST_ID_BITS + SERIAL_BITS;
+use constant SERIAL_SHIFT => HOST_ID_BITS;
+
+use constant SERIAL_INCREMENT => Math::BigInt->new(1) << SERIAL_SHIFT;
+
+use constant HOST_ID_MAX => (Math::BigInt->new(1) << HOST_ID_BITS) - 1;
+use constant TIME_MAX => (Math::BigInt->new(1) << TIME_BITS) - 1;
+use constant TIME_MAX_SHIFTED => TIME_MAX << TIME_SHIFT;
+use constant SERIAL_MAX => (Math::BigInt->new(1) << SERIAL_BITS) - 1;
+use constant SERIAL_MAX_SHIFTED => SERIAL_MAX << SERIAL_SHIFT;
+
+
+sub new {
+    my $self = shift;
+    $self = fields::new( $self ) unless ref $self;
+
+    my $host_id = shift;
+    if( !$host_id ) {
+        $host_id = int( rand( HOST_ID_MAX ) );
+    } elsif( $host_id < 0 || $host_id > HOST_ID_MAX ) {
+        warn __PACKAGE__ . ": host ID $host_id is not in range of [0," . HOST_ID_MAX . "]\n";
+        return;
+    }
+
+    $self->{ host_id } = $host_id;
+    $self->{ start_time } = time;
+    $self->{ current_time } = 0;
+    $self->{ ids } = {};
+    $self->_sync();
+
+    return $self;
+}
+
+
+sub _sync {
+    my $self = shift;
+    my $time = time;
+    return if( $self->{ current_time } == $time ); # FIXME: check for clock skew
+    $self->{ current_time } = $time;
+    $self->{ min_id } = $self->_make_id( 0 ) unless( $self->{ min_id } );
+    $self->{ max_id } = $self->_make_id( SERIAL_MAX );
+}
+
+
+sub _make_id {
+    my $self = shift;
+    my $serial = shift || 0;
+    return
+        ((Math::BigInt->new( $self->{ current_time } - EPOCH_OFFSET )) << TIME_SHIFT)
+            | (Math::BigInt->new($serial) << SERIAL_SHIFT) | $self->{ host_id };
+}
+
 
 sub get_id {
     my $self = shift;
-    return sha1_hex( time() . rand() );
+    my $key = shift || "_";
+    $self->_sync();
+
+    if( !exists $self->{ ids }->{ $key } ) {
+        $self->{ ids }->{ $key } = $self->{ min_id };
+        return $self->{ ids }->{ $key };
+    }
+
+    return if( $self->{ ids }->{ $key } >= $self->{ max_id } );
+
+    $self->{ ids }->{ $key } += SERIAL_INCREMENT;
+    return $self->{ ids }->{ $key };
 }
 
+
 1;