get attachment ID based on src

gistfile1.php

/** 
 * This is helper function will get attachment ID based on src
 * 
 * @see http://wordpress.org/support/topic/need-to-get-attachment-id-by-image-url
 */
function get_attachment_id_from_src( $url ) {

	global $wpdb;
	$id = url_to_postid( $url );
	if( $id == 0 ) {
		$fileupload_url = get_option( 'fileupload_url', null ).'/';
		if ( strpos($url,$fileupload_url)!== false ) {
			$url = str_replace( $fileupload_url,'',$url );
			$id = $wpdb->get_var( $wpdb->prepare( "SELECT wposts.ID FROM $wpdb->posts wposts, $wpdb->postmeta wpostmeta WHERE wposts.ID = wpostmeta.post_id AND wpostmeta.meta_key = '_wp_attached_file' AND wpostmeta.meta_value = '%s' AND wposts.post_type = 'attachment'", $url ) );
		}
	}
	return $id;

}