New search system, including date: and pubdate: and combination

Now also accepts combination of #tag and intitle: and inurl: and author:
and the new date: and pubdate:
https://github.com/marienfressinaud/FreshRSS/issues/511
Each search prefix stop at the first space (we should add a possibility
to have quotes for multiple words)
So if you want two words in title, write "intitle:word1 intitle:word2"

Examples of dates:
date:2014
date:2014-02/2014-04 or date:201402/201404
date:P1W for the last week

1 files changed, 130 insertions, 0 deletions

diff --git a/lib/lib_date.php b/lib/lib_date.php
new file mode 100644
index 000000000..ab7975852
--- /dev/null
+++ b/lib/lib_date.php
@@ -0,0 +1,130 @@
+<?php
+/**
+ * Author: Alexandre Alapetite http://alexandre.alapetite.fr
+ * 2014-06-01
+ * License: GNU AGPLv3 http://www.gnu.org/licenses/agpl-3.0.html
+ *
+ * Parser of ISO 8601 time intervals http://en.wikipedia.org/wiki/ISO_8601#Time_intervals
+ *	Examples: "2014-02/2014-04", "2014-02/04", "2014-06", "P1M"
+ */
+
+/*
+example('2014-03');
+example('201403');
+example('2014-03-30');
+example('2014-05-30T13');
+example('2014-05-30T13:30');
+example('2014-02/2014-04');
+example('2014-02--2014-04');
+example('2014-02/04');
+example('2014-02-03/05');
+example('2014-02-03T22:00/22:15');
+example('2014-02-03T22:00/15');
+example('2014-03/');
+example('/2014-03');
+example('2014-03/P1W');
+example('P1W/2014-05-25T23:59:59');
+example('P1Y/');
+example('P1Y');
+example('P2M/');
+example('P3W/');
+example('P4D/');
+example('PT5H/');
+example('PT6M/');
+example('PT7S/');
+example('P1DT1H/');
+
+function example($dateInterval) {
+	$dateIntervalArray = parseDateInterval($dateInterval);
+	echo $dateInterval, "\t=>\t",
+		$dateIntervalArray[0] == null ? 'null' : @date('c', $dateIntervalArray[0]), '/',
+		$dateIntervalArray[1] == null ? 'null' : @date('c', $dateIntervalArray[1]), "\n";
+}
+*/
+
+function _dateFloor($isoDate) {
+	$x = explode('T', $isoDate, 2);
+	$t = isset($x[1]) ? str_pad($x[1], 6, '0') : '000000';
+	return str_pad($x[0], 8, '01') . 'T' . $t;
+}
+
+function _dateCeiling($isoDate) {
+	$x = explode('T', $isoDate, 2);
+	$t = isset($x[1]) && strlen($x[1]) > 1 ? str_pad($x[1], 6, '59') : '235959';
+	switch (strlen($x[0])) {
+		case 4:
+			return $x[0] . '1231T' . $t;
+		case 6:
+			$d = @strtotime($x[0] . '01');
+			return $x[0] . date('t', $d) . 'T' . $t;
+		default:
+			return $x[0] . 'T' . $t;
+	}
+}
+
+function _noDelimit($isoDate) {
+	return $isoDate === null || $isoDate === '' ? null :
+		str_replace(array('-', ':'), '', $isoDate);	//FIXME: Bug with negative time zone
+}
+
+function _dateRelative($d1, $d2) {
+	if ($d2 === null) {
+		return $d1 !== null && $d1[0] !== 'P' ? $d1 : null;
+	} elseif ($d2 !== '' && $d2[0] != 'P' && $d1 !== null && $d1[0] !== 'P') {
+		$y2 = substr($d2, 0, 4);
+		if (strlen($y2) < 4 || !ctype_digit($y2)) {	//Does not start by a year
+			$d2 = _noDelimit($d2);
+			return substr($d1, 0, -strlen($d2)) . $d2;	//Add prefix from $d1
+		}
+	}
+	return _noDelimit($d2);
+}
+
+/**
+ * Parameter $dateInterval is a string containing an ISO 8601 time intervals.
+ * Returns an array with the minimum and maximum Unix timestamp of this interval, or null if open interval.
+ */
+function parseDateInterval($dateInterval) {
+	$dateInterval = trim($dateInterval);
+	$dateInterval = str_replace('--', '/', $dateInterval);
+	$dateInterval = strtoupper($dateInterval);
+	$min = null;
+	$max = null;
+	$x = explode('/', $dateInterval, 2);
+	$d1 = _noDelimit($x[0]);
+	$d2 = _dateRelative($d1, count($x) > 1 ? $x[1] : null);
+	if ($d1 !== null && $d1[0] !== 'P') {
+		$min = @strtotime(_dateFloor($d1));
+	}
+	if ($d2 !== null) {
+		if ($d2[0] === 'P') {
+			try {
+				$di2 = new DateInterval($d2);
+				$dt1 = @date_create();	//new DateTime() would create an Exception if the default time zone is not defined
+				if ($min !== null && $min !== false) {
+					$dt1->setTimestamp($min);
+				}
+				$max = $dt1->add($di2)->getTimestamp() - 1;
+			} catch (Exception $e) {
+				$max = false;
+			}
+		} elseif ($d1 === null || $d1[0] !== 'P') {
+			$max = @strtotime(_dateCeiling($d2));
+		} else {
+			$max = @strtotime($d2);
+		}
+	}
+	if ($d1 !== null && $d1[0] === 'P') {
+		try {
+			$di1 = new DateInterval($d1);
+			$dt2 = @date_create();
+			if ($max !== null && $max !== false) {
+				$dt2->setTimestamp($max);
+			}
+			$min = $dt2->sub($di1)->getTimestamp() + 1;
+		} catch (Exception $e) {
+				$min = false;
+		}
+	}
+	return array($min, $max);
+}