--- /dev/null
+<?php
+
+namespace Cdb;
+
+/**
+ * Native CDB file reader and writer.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * @file
+ */
+
+/**
+ * Read from a CDB file.
+ * Native and pure PHP implementations are provided.
+ * http://cr.yp.to/cdb.html
+ */
+abstract class Reader {
+ /**
+ * The file handle
+ */
+ protected $handle;
+
+ /**
+ * Open a file and return a subclass instance
+ *
+ * @param string $fileName
+ *
+ * @return Reader
+ */
+ public static function open( $fileName ) {
+ return self::haveExtension() ?
+ new Reader\DBA( $fileName ) :
+ new Reader\PHP( $fileName );
+ }
+
+ /**
+ * Returns true if the native extension is available
+ *
+ * @return bool
+ */
+ public static function haveExtension() {
+ if ( !function_exists( 'dba_handlers' ) ) {
+ return false;
+ }
+ $handlers = dba_handlers();
+ if ( !in_array( 'cdb', $handlers ) || !in_array( 'cdb_make', $handlers ) ) {
+ return false;
+ }
+
+ return true;
+ }
+
+ /**
+ * Create the object and open the file
+ *
+ * @param string $fileName
+ */
+ abstract public function __construct( $fileName );
+
+ /**
+ * Close the file. Optional, you can just let the variable go out of scope.
+ */
+ abstract public function close();
+
+ /**
+ * Get a value with a given key. Only string values are supported.
+ *
+ * @param string $key
+ */
+ abstract public function get( $key );
+
+ /**
+ * Check whether key exists
+ *
+ * @param string $key
+ */
+ abstract public function exists( $key );
+
+ /**
+ * Fetch first key
+ */
+ abstract public function firstkey();
+
+ /**
+ * Fetch next key
+ */
+ abstract public function nextkey();
+}