<?php
/**
* ARC2 N-Triples Serializer
*
* @author Benjamin Nowack
* @license <http://arc.semsol.org/license>
* @homepage <http://arc.semsol.org/>
* @package ARC2
*/
ARC2::inc('RDFSerializer');
class ARC2_NTriplesSerializer extends ARC2_RDFSerializer {
function __construct($a, &$caller) {
parent::__construct($a, $caller);
}
function __init() {
parent::__init();
$this->esc_chars = array();
$this->raw = 0;
}
/* */
function getTerm($v, $term = '') {
// type detection
if (!is_array($v) || empty($v['type'])) {
// bnode
if (preg_match('/^\_\:/', $v)) {
return $this->getTerm(array('value' => $v, 'type' => 'bnode'));
}
// uri
if (preg_match('/^[a-z0-9]+\:[^\s\"]*$/is' . ($this->has_pcre_unicode ? 'u' : ''), $v)) {
return $this->getTerm(array('value' => $v, 'type' => 'uri'));
}
// fallback for non-unicode environments: subjects and predicates can't be literals.
if (in_array($term, array('s', 'p'))) {
return $this->getTerm(array('value' => $v, 'type' => 'uri'));
}
// assume literal
return $this->getTerm(array('type' => 'literal', 'value' => $v));
}
if ($v['type'] == 'bnode') {
return $v['value'];
}
elseif ($v['type'] == 'uri') {
return '<' . $this->escape($v['value']) . '>';
}
// something went wrong
elseif ($v['type'] != 'literal') {
return $this->getTerm($v['value']);
}
/* literal */
$quot = '"';
if ($this->raw && preg_match('/\"/', $v['value'])) {
$quot = "'";
if (preg_match('/\'/', $v['value'])) {
$quot = '"""';
if (preg_match('/\"\"\"/', $v['value']) || preg_match('/\"$/', $v['value']) || preg_match('/^\"/', $v['value'])) {
$quot = "'''";
$v['value'] = preg_replace("/'$/", "' ", $v['value']);
$v['value'] = preg_replace("/^'/", " '", $v['value']);
$v['value'] = str_replace("'''", '\\\'\\\'\\\'', $v['value']);
}
}
}
if ($this->raw && (strlen($quot) == 1) && preg_match('/[\x0d\x0a]/', $v['value'])) {
$quot = $quot . $quot . $quot;
}
$suffix = isset($v['lang']) && $v['lang'] ? '@' . $v['lang'] : '';
$suffix = isset($v['datatype']) && $v['datatype'] ? '^^' . $this->getTerm($v['datatype']) : $suffix;
//return $quot . "object" . utf8_encode($v['value']) . $quot . $suffix;
return $quot . $this->escape($v['value']) . $quot . $suffix;
}
function getSerializedIndex($index, $raw = 0) {
$this->raw = $raw;
$r = '';
$nl = "\n";
foreach ($index as $s => $ps) {
$s = $this->getTerm($s, 's');
foreach ($ps as $p => $os) {
$p = $this->getTerm($p, 'p');
if (!is_array($os)) {/* single literal o */
$os = array(array('value' => $os, 'type' => 'literal'));
}
foreach ($os as $o) {
$o = $this->getTerm($o, 'o‚');
$r .= $r ? $nl : '';
$r .= $s . ' ' . $p . ' ' . $o . ' .';
}
}
}
return $r . $nl;
}
/* */
function escape($v) {
$r = '';
// decode, if possible
$v = (strpos(utf8_decode(str_replace('?', '', $v)), '?') === false) ? utf8_decode($v) : $v;
if ($this->raw) return $v;// no further escaping wanted
// escape tabs and linefeeds
$v = str_replace(array("\t", "\r", "\n"), array('\t', '\r', '\n'), $v);
// escape non-ascii-chars
$v = preg_replace_callback('/([^a-zA-Z0-9 \!\#\$\%\&\(\)\*\+\,\-\.\/\:\;\=\?\@\^\_\{\|\}]+)/', array($this, 'escapeChars'), $v);
return $v;
}
function escapeChars($matches) {
$v = $matches[1];
$r = '';
// loop through mb chars
if (function_exists('mb_strlen')) {
for ($i = 0, $i_max = mb_strlen($v, 'UTF-8'); $i < $i_max; $i++) {
$c = mb_substr($v, $i, 1, 'UTF-8');
if (!isset($this->esc_chars[$c])) {
$this->esc_chars[$c] = $this->getEscapedChar($c, $this->getCharNo($c, 1));
}
$r .= $this->esc_chars[$c];
}
}
// fall back to built-in JSON functionality, if available
else if (function_exists('json_encode')) {
$r = json_encode($v);
if ($r == 'null') $r = json_encode (utf8_encode($v));
// remove boundary quotes
if (substr($r, 0, 1) == '"') $r = substr($r, 1);
if (substr($r, -1) == '"') $r = substr($r, 0, -1);
// uppercase hex chars
$r = preg_replace('/(\\\u)([0-9a-f]{4})/e', "'\\1' . strtoupper('\\2')", $r);
$r = preg_replace('/(\\\U)([0-9a-f]{8})/e', "'\\1' . strtoupper('\\2')", $r);
}
// escape byte-wise (may be wrong for mb chars and newer php versions)
else {
for ($i = 0, $i_max = strlen($v); $i < $i_max; $i++) {
$c = $v[$i];
if (!isset($this->esc_chars[$c])) {
$this->esc_chars[$c] = $this->getEscapedChar($c, $this->getCharNo($c));
}
$r .= $this->esc_chars[$c];
}
}
return $r;
}
/* */
function getCharNo($c, $is_encoded = false) {
$c_utf = $is_encoded ? $c : utf8_encode($c);
$bl = strlen($c_utf);/* binary length */
$r = 0;
switch ($bl) {
case 1:/* 0####### (0-127) */
$r = ord($c_utf);
break;
case 2:/* 110##### 10###### = 192+x 128+x */
$r = ((ord($c_utf[0]) - 192) * 64) + (ord($c_utf[1]) - 128);
break;
case 3:/* 1110#### 10###### 10###### = 224+x 128+x 128+x */
$r = ((ord($c_utf[0]) - 224) * 4096) + ((ord($c_utf[1]) - 128) * 64) + (ord($c_utf[2]) - 128);
break;
case 4:/* 1111#### 10###### 10###### 10###### = 240+x 128+x 128+x 128+x */
$r = ((ord($c_utf[0]) - 240) * 262144) + ((ord($c_utf[1]) - 128) * 4096) + ((ord($c_utf[2]) - 128) * 64) + (ord($c_utf[3]) - 128);
break;
}
return $r;
}
function getEscapedChar($c, $no) {/*see http://www.w3.org/TR/rdf-testcases/#ntrip_strings */
if ($no < 9) return "\\u" . sprintf('%04X', $no); /* #x0-#x8 (0-8) */
if ($no == 9) return '\t'; /* #x9 (9) */
if ($no == 10) return '\n'; /* #xA (10) */
if ($no < 13) return "\\u" . sprintf('%04X', $no); /* #xB-#xC (11-12) */
if ($no == 13) return '\r'; /* #xD (13) */
if ($no < 32) return "\\u" . sprintf('%04X', $no); /* #xE-#x1F (14-31) */
if ($no < 34) return $c; /* #x20-#x21 (32-33) */
if ($no == 34) return '\"'; /* #x22 (34) */
if ($no < 92) return $c; /* #x23-#x5B (35-91) */
if ($no == 92) return '\\'; /* #x5C (92) */
if ($no < 127) return $c; /* #x5D-#x7E (93-126) */
if ($no < 65536) return "\\u" . sprintf('%04X', $no); /* #x7F-#xFFFF (128-65535) */
if ($no < 1114112) return "\\U" . sprintf('%08X', $no); /* #x10000-#x10FFFF (65536-1114111) */
return ''; /* not defined => ignore */
}
/* */
}