<?php


    // input: filename
    // ouptut: filename extention
    //     or
    //         -1
    function fileGetExtention( $filename ) {

        $retvalue = "";
        $tmp = explode( ".", $filename );

        if( $tmp[1] ) {
            $retvalue = $tmp[ count( $tmp ) - 1 ];
        }
        else {
            $retvalue = -1;
        }

        return $retvalue ;

    } // function


    // Self Validation Code
    // This portion only runs if this script is called directly.
    // This script is meant to be 'included'  into another PHP script
    if( basename( $GLOBALS["PHP_SELF"] ) == "lib_file.php" ) {

        $test_pass_values = array( "./foo.bar",
                                   "./this_is/a/long_directory/foo.bar",
                                   "./this_is/a/long_directory/foo.bar.test.text",
                                   "file.bak" );

        $test_fail_values = array( "",
                                   "...",
                                   "3",
                                   "file",
                                   array( "asd", "wer.txt" ) );

        echo "<p>passing tests</p>\n";
        while( list( $k, $v ) = each( $test_pass_values ) ) {
            echo "$v >>> " . fileGetExtention( $v ) . "<br>\n";
        }

        echo "<p>failing tests</p>\n";
        while( list( $k, $v ) = each( $test_fail_values ) ) {
            echo "$v >>> " . fileGetExtention( $v ) . "<br>\n";
        }

    }

?>