gistfile1.php

<?php
add_filter( 'gform_shortcode_form', 'tgm_filter_data', 10, 3 );
function tgm_filter_data( $form, $atts, $content ) {

	/** Get the saved data from the current user (or return early if there is none to format) */
	$data = json_decode( get_user_meta( get_current_user_id(), 'casting_form_data', true ) );
	if ( empty( $data ) )
		return $form;
		
	/** Also go ahead and grab any file data as well */
	$files = json_decode( $data->gform_uploaded_files_1 );

	/** Require the simple DOM parser library */
	require get_stylesheet_directory() . '/lib/php/simple_html_dom.php';
	
	/** Get the HTML from the form string */
	$html = str_get_html( $form );
	
	/** Loop through the form input fields and update values */
	foreach ( $html->find('input') as $obj ) {	
		foreach ( $data as $key => $val ) {
			if ( ( $key == $obj->attr['id'] ) && ! empty( $val ) ) {
				if ( preg_match( '#^choice#', $key ) )
					$obj->attr['checked'] = $val;
				else
					$obj->attr['value'] = $val;
			}
		}
	}
	
	/** Loop through the form input file fields and update values */
	foreach ( $html->find('input[type="file"]') as $obj ) {	
		foreach ( (array) $files as $key => $val ) {
			if ( ( $key == $obj->attr['name'] ) && ! empty( $val ) ) {
				$obj->attr['value'] = $val;
			}
		}
	}
	
	/** Loop through the form select fields and update values */
	foreach ( $html->find('select') as $obj ) {	
		foreach ( $data as $key => $val ) {
			if ( ( $key == $obj->attr['id'] ) && ! empty( $val ) ) {
				foreach ( $obj->children as $option ) {
					if ( isset( $option->attr['value'] ) && $val == $option->attr['value'] )
						$option->attr['selected'] = 'selected';
				}
			}
		}
	}
	
	/** Loop through the form textareas and update values */
	foreach ( $html->find('textarea') as $obj ) {	
		foreach ( $data as $key => $val ) {
			if ( ( $key == $obj->attr['id'] ) && ! empty( $val ) ) {
				$obj->innertext = $val;
			}
		}
	}
	
	/** Return the Simple DOM HTML instead of the regular HTML */
	return $html;

}