<?php
/**
* Atom Syndication Format PHP Library
*
* @package AtomLib
* @link http://code.google.com/p/phpatomlib/
*
* @author Elias Torres <elias@torrez.us>
* @version 0.4
* @since 2.3.0
*/

/**
* Structure that store common Atom Feed Properties
*
* @package AtomLib
*/
class AtomFeed {
/**
* Stores Links
* @var array
* @access public
*/
var $links = array();
/**
* Stores Categories
* @var array
* @access public
*/
var $categories = array();
/**
* Stores Entries
*
* @var array
* @access public
*/
var $entries = array();
}

/**
* Structure that store Atom Entry Properties
*
* @package AtomLib
*/
class AtomEntry {
/**
* Stores Links
* @var array
* @access public
*/
var $links = array();
/**
* Stores Categories
* @var array
* @access public
*/
var $categories = array();
}

/**
* AtomLib Atom Parser API
*
* @package AtomLib
*/
class AtomParser {

var $NS = 'http://www.w3.org/2005/Atom';
var $ATOM_CONTENT_ELEMENTS = array('content','summary','title','subtitle','rights');
var $ATOM_SIMPLE_ELEMENTS = array('id','updated','published','draft');

var $debug = false;

var $depth = 0;
var $indent = 2;
var $in_content;
var $ns_contexts = array();
var $ns_decls = array();
var $content_ns_decls = array();
var $content_ns_contexts = array();
var $is_xhtml = false;
var $is_html = false;
var $is_text = true;
var $skipped_div = false;

var $FILE = "php://input";

var $feed;
var $current;
var $map_attrs_func;
var $map_xmlns_func;
var $error;
var $content;

/**
* PHP5 constructor.
*/
function __construct() {

$this->feed = new AtomFeed();
$this->current = null;
$this->map_attrs_func = array( __CLASS__, 'map_attrs' );
$this->map_xmlns_func = array( __CLASS__, 'map_xmlns' );
}

/**
* PHP4 constructor.
*/
public function AtomParser() {
self::__construct();
}

/**
* Map attributes to key="val"
*
* @param string $k Key
* @param string $v Value
* @return string
*/
public static function map_attrs($k, $v) {
return "$k=\"$v\"";
}

/**
* Map XML namespace to string.
*
* @param indexish $p XML Namespace element index
* @param array $n Two-element array pair. [ 0 => {namespace}, 1 => {url} ]
* @return string 'xmlns="{url}"' or 'xmlns:{namespace}="{url}"'
*/
public static function map_xmlns($p, $n) {
$xd = "xmlns";
if( 0 < strlen($n[0]) ) {
$xd .= ":{$n[0]}";
}
return "{$xd}=\"{$n[1]}\"";
}

function _p($msg) {
if($this->debug) {
print str_repeat(" ", $this->depth * $this->indent) . $msg ."\n";
}
}

function error_handler($log_level, $log_text, $error_file, $error_line) {
$this->error = $log_text;
}

function parse() {

set_error_handler(array(&$this, 'error_handler'));

array_unshift($this->ns_contexts, array());

if ( ! function_exists( 'xml_parser_create_ns' ) ) {
trigger_error( __( "PHP's XML extension is not available. Please contact your hosting provider to enable PHP's XML extension." ) );
return false;
}

$parser = xml_parser_create_ns();
xml_set_element_handler($parser, array($this, "start_element"), array($this, "end_element"));
xml_parser_set_option($parser,XML_OPTION_CASE_FOLDING,0);
xml_parser_set_option($parser,XML_OPTION_SKIP_WHITE,0);
xml_set_character_data_handler($parser, array($this, "cdata"));
xml_set_default_handler($parser, array($this, "_default"));
xml_set_start_namespace_decl_handler($parser, array($this, "start_ns"));
xml_set_end_namespace_decl_handler($parser, array($this, "end_ns"));

$this->content = '';

$ret = true;

$fp = fopen($this->FILE, "r");
while ($data = fread($fp, 4096)) {
if($this->debug) $this->content .= $data;

if(!xml_parse($parser, $data, feof($fp))) {
/* translators: 1: Error message, 2: Line number. */
trigger_error(sprintf(__('XML Error: %1$s at line %2$s')."\n",
xml_error_string(xml_get_error_code($parser)),
xml_get_current_line_number($parser)));
$ret = false;
break;
}
}
fclose($fp);

xml_parser_free($parser);
unset($parser);

restore_error_handler();

return $ret;
}

function start_element($parser, $name, $attrs) {

$name_parts = explode(":", $name);
$tag = array_pop($name_parts);

switch($name) {
case $this->NS . ':feed':
$this->current = $this->feed;
break;
case $this->NS . ':entry':
$this->current = new AtomEntry();
break;
};

$this->_p("start_element('$name')");
#$this->_p(print_r($this->ns_contexts,true));
#$this->_p('current(' . $this->current . ')');

array_unshift($this->ns_contexts, $this->ns_decls);

$this->depth++;

if(!empty($this->in_content)) {

$this->content_ns_decls = array();

if($this->is_html || $this->is_text)
trigger_error("Invalid content in element found. Content must not be of type text or html if it contains markup.");

$attrs_prefix = array();

// resolve prefixes for attributes
foreach($attrs as $key => $value) {
$with_prefix = $this->ns_to_prefix($key, true);
$attrs_prefix[$with_prefix[1]] = $this->xml_escape($value);
}

$attrs_str = join(' ', array_map($this->map_attrs_func, array_keys($attrs_prefix), array_values($attrs_prefix)));
if(strlen($attrs_str) > 0) {
$attrs_str = " " . $attrs_str;
}

$with_prefix = $this->ns_to_prefix($name);

if(!$this->is_declared_content_ns($with_prefix[0])) {
array_push($this->content_ns_decls, $with_prefix[0]);
}

$xmlns_str = '';
if(count($this->content_ns_decls) > 0) {
array_unshift($this->content_ns_contexts, $this->content_ns_decls);
$xmlns_str .= join(' ', array_map($this->map_xmlns_func, array_keys($this->content_ns_contexts[0]), array_values($this->content_ns_contexts[0])));
if(strlen($xmlns_str) > 0) {
$xmlns_str = " " . $xmlns_str;
}
}

array_push($this->in_content, array($tag, $this->depth, "<". $with_prefix[1] ."{$xmlns_str}{$attrs_str}" . ">"));

} else if(in_array($tag, $this->ATOM_CONTENT_ELEMENTS) || in_array($tag, $this->ATOM_SIMPLE_ELEMENTS)) {
$this->in_content = array();
$this->is_xhtml = $attrs['type'] == 'xhtml';
$this->is_html = $attrs['type'] == 'html' || $attrs['type'] == 'text/html';
$this->is_text = !in_array('type',array_keys($attrs)) || $attrs['type'] == 'text';
$type = $this->is_xhtml ? 'XHTML' : ($this->is_html ? 'HTML' : ($this->is_text ? 'TEXT' : $attrs['type']));

if(in_array('src',array_keys($attrs))) {
$this->current->$tag = $attrs;
} else {
array_push($this->in_content, array($tag,$this->depth, $type));
}
} else if($tag == 'link') {
array_push($this->current->links, $attrs);
} else if($tag == 'category') {
array_push($this->current->categories, $attrs);
}

$this->ns_decls = array();
}

function end_element($parser, $name) {

$name_parts = explode(":", $name);
$tag = array_pop($name_parts);

$ccount = count($this->in_content);

# if we are *in* content, then let's proceed to serialize it
if(!empty($this->in_content)) {
# if we are ending the original content element
# then let's finalize the content
if($this->in_content[0][0] == $tag &&
$this->in_content[0][1] == $this->depth) {
$origtype = $this->in_content[0][2];
array_shift($this->in_content);
$newcontent = array();
foreach($this->in_content as $c) {
if(count($c) == 3) {
array_push($newcontent, $c[2]);
} else {
if($this->is_xhtml || $this->is_text) {
array_push($newcontent, $this->xml_escape($c));
} else {
array_push($newcontent, $c);
}
}
}
if(in_array($tag, $this->ATOM_CONTENT_ELEMENTS)) {
$this->current->$tag = array($origtype, join('',$newcontent));
} else {
$this->current->$tag = join('',$newcontent);
}
$this->in_content = array();
} else if($this->in_content[$ccount-1][0] == $tag &&
$this->in_content[$ccount-1][1] == $this->depth) {
$this->in_content[$ccount-1][2] = substr($this->in_content[$ccount-1][2],0,-1) . "/>";
} else {
# else, just finalize the current element's content
$endtag = $this->ns_to_prefix($name);
array_push($this->in_content, array($tag, $this->depth, "</$endtag[1]>"));
}
}

array_shift($this->ns_contexts);

$this->depth--;

if($name == ($this->NS . ':entry')) {
array_push($this->feed->entries, $this->current);
$this->current = null;
}

$this->_p("end_element('$name')");
}

function start_ns($parser, $prefix, $uri) {
$this->_p("starting: " . $prefix . ":" . $uri);
array_push($this->ns_decls, array($prefix,$uri));
}

function end_ns($parser, $prefix) {
$this->_p("ending: #" . $prefix . "#");
}

function cdata($parser, $data) {
$this->_p("data: #" . str_replace(array("\n"), array("\\n"), trim($data)) . "#");
if(!empty($this->in_content)) {
array_push($this->in_content, $data);
}
}

function _default($parser, $data) {
# when does this gets called?
}


function ns_to_prefix($qname, $attr=false) {
# split 'http://www.w3.org/1999/xhtml:div' into ('http','//www.w3.org/1999/xhtml','div')
$components = explode(":", $qname);

# grab the last one (e.g 'div')
$name = array_pop($components);

if(!empty($components)) {
# re-join back the namespace component
$ns = join(":",$components);
foreach($this->ns_contexts as $context) {
foreach($context as $mapping) {
if($mapping[1] == $ns && strlen($mapping[0]) > 0) {
return array($mapping, "$mapping[0]:$name");
}
}
}
}

if($attr) {
return array(null, $name);
} else {
foreach($this->ns_contexts as $context) {
foreach($context as $mapping) {
if(strlen($mapping[0]) == 0) {
return array($mapping, $name);
}
}
}
}
}

function is_declared_content_ns($new_mapping) {
foreach($this->content_ns_contexts as $context) {
foreach($context as $mapping) {
if($new_mapping == $mapping) {
return true;
}
}
}
return false;
}

function xml_escape($content)
{
return str_replace(array('&','"',"'",'<','>'),
array('&amp;','&quot;','&apos;','&lt;','&gt;'),
$content );
}
}