[gnome-maps/wip/mlundblad/transit-routing: 20/32] Add module with time utility functions

[Marcus Lundblad <mlundblad src gnome org>]

commit 58150bce42f8fa6ad90f904be909c3e33842d085
Author: Marcus Lundblad <ml update uu se>
Date:   Sun Feb 12 21:40:20 2017 +0100

    Add module with time utility functions
    
    Currently contains a function to parse an
    entered time into a normalized HH:MM string
    format.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=755808

 src/org.gnome.Maps.src.gresource.xml |    1 +
 src/time.js                          |   91 ++++++++++++++++++++++++++++++++++
 2 files changed, 92 insertions(+), 0 deletions(-)
---
diff --git a/src/org.gnome.Maps.src.gresource.xml b/src/org.gnome.Maps.src.gresource.xml
index 5442def..c440866 100644
--- a/src/org.gnome.Maps.src.gresource.xml
+++ b/src/org.gnome.Maps.src.gresource.xml
@@ -76,6 +76,7 @@
     <file>socialPlaceListBox.js</file>
     <file>socialPlaceMatcher.js</file>
     <file>storedRoute.js</file>
+    <file>time.js</file>
     <file>togeojson/togeojson.js</file>
     <file>transitArrivalRow.js</file>
     <file>transitItineraryRow.js</file>
diff --git a/src/time.js b/src/time.js
new file mode 100644
index 0000000..2fe4317
--- /dev/null
+++ b/src/time.js
@@ -0,0 +1,91 @@
+/* -*- Mode: JS2; indent-tabs-mode: nil; js2-basic-offset: 4 -*- */
+/* vim: set et ts=4 sw=4: */
+/*
+ * Copyright (c) 2017, Marcus Lundblad
+ *
+ * GNOME Maps is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ *
+ * GNOME Maps is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+ * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with GNOME Maps; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Author: Marcus Lundblad <ml update uu se>
+ */
+
+/* parse a time from a fixed set of free-formats into a string representation:
+ * hour:min
+ *
+ * Examples:
+ * "10:00" → "10:00"
+ * "1:00pm" → "13:00"
+ * "0800" → "08:00"
+ * "10.30" → "10:30"
+ * "12" → "12:00"
+ *
+ * TODO: maybe try to use some library to get better locale handling,
+ * or push for something in GLib */
+function parseTimeString(timeString) {
+    let pmSet = false;
+    let hours;
+    let mins;
+    /* remove extra whitespaces */
+    timeString = timeString.replace(/\s+/g, '');
+
+    if (timeString.endsWith('am')) {
+        timeString = timeString.substring(0, timeString.length - 2);
+    } else if (timeString.endsWith('pm')) {
+        timeString = timeString.substring(0, timeString.length - 2);
+        pmSet = true;
+    }
+
+    /* allow using :, ., and the ratio symbol to separate hours:mins */
+    if (timeString.charAt(2) === ':' || timeString.charAt(1) === ':')
+        timeString = timeString.replace(':', '');
+    else if (timeString.charAt(2) === '.' || timeString.charAt(1) === '.')
+        timeString = timeString.replace('.', '');
+    else if (timeString.charAt(2) === '\u2236' ||
+             timeString.charAt(1) === '\u2236')
+        timeString = timeString.replace('\u2236', '');
+
+    if (timeString.length === 4) {
+        /* expect a full time specification (hours, minutes) */
+        hours = timeString.substring(0, 2);
+        mins = timeString.substring(2, 4);
+    } else if (timeString.length === 3) {
+        /* interpret a 3 digit string as h:mm */
+        hours = '0' + timeString.substring(0, 1);
+        mins = timeString.substring(1, 3);
+    } else if (timeString.length === 2) {
+        /* expect just the hour part */
+        hours = timeString.substring(0, 2);
+        mins = '00';
+    } else if (timeString.length === 1) {
+        /* expect just the hour part, one digit */
+        hours = '0' + timeString;
+        mins = '00';
+    } else {
+        /* this makes no sense, just bail out */
+        return null;
+    }
+
+    /* check if the parts can be interpreted as numbers */
+    if (hours % 1 === 0 && mins % 1 === 0) {
+        if (pmSet)
+            hours = parseInt(hours) + 12;
+
+        /* if the hours or minutes is out-of-range, bail out */
+        if (hours < 0 || hours > 24 || mins < 0 || mins > 59)
+            return null;
+
+        return hours + ':' + mins;
+    } else {
+        return null;
+    }
+}