From 5953940291655be97dfd25d43c0cf0a6b4e38edf Mon Sep 17 00:00:00 2001
From: =?utf8?q?David=20=E2=80=98Bombe=E2=80=99=20Roden?=
 <bombe@pterodactylus.net>
Date: Sun, 29 Jul 2012 00:34:26 +0200
Subject: [PATCH] Add filter for concise numbers (three most significant digits
 only).

---
 .../demoscenemusic/core/TemplateServlet.java       |  2 +
 .../template/ConciseNumberFilter.java              | 62 ++++++++++++++++++++++
 2 files changed, 64 insertions(+)
 create mode 100644 src/main/java/net/pterodactylus/demoscenemusic/template/ConciseNumberFilter.java

diff --git a/src/main/java/net/pterodactylus/demoscenemusic/core/TemplateServlet.java b/src/main/java/net/pterodactylus/demoscenemusic/core/TemplateServlet.java
index b6107a6..7b4f8c7 100644
--- a/src/main/java/net/pterodactylus/demoscenemusic/core/TemplateServlet.java
+++ b/src/main/java/net/pterodactylus/demoscenemusic/core/TemplateServlet.java
@@ -44,6 +44,7 @@ import net.pterodactylus.demoscenemusic.data.Track;
 import net.pterodactylus.demoscenemusic.data.TrackDerivative;
 import net.pterodactylus.demoscenemusic.data.User;
 import net.pterodactylus.demoscenemusic.page.ServletRequest;
+import net.pterodactylus.demoscenemusic.template.ConciseNumberFilter;
 import net.pterodactylus.demoscenemusic.template.DurationFilter;
 import net.pterodactylus.demoscenemusic.template.PropertiesAccessor;
 import net.pterodactylus.demoscenemusic.template.TrackDerivativeAccessor;
@@ -121,6 +122,7 @@ public class TemplateServlet extends HttpServlet {
 		templateContextFactory.addFilter("sort", sortFilter);
 		templateContextFactory.addFilter("matches", new MatchFilter());
 		templateContextFactory.addFilter("time", new DurationFilter());
+		templateContextFactory.addFilter("concise", new ConciseNumberFilter());
 
 		templateContextFactory.addTemplateObject("core", core);
 		templateContextFactory.addTemplateObject("dataManager", core.getDataManager());
diff --git a/src/main/java/net/pterodactylus/demoscenemusic/template/ConciseNumberFilter.java b/src/main/java/net/pterodactylus/demoscenemusic/template/ConciseNumberFilter.java
new file mode 100644
index 0000000..9ea4b8c
--- /dev/null
+++ b/src/main/java/net/pterodactylus/demoscenemusic/template/ConciseNumberFilter.java
@@ -0,0 +1,62 @@
+/*
+ * DemosceneMusic - ConciseNumberFilter.java - Copyright © 2012 David Roden
+ *
+ * This program 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 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package net.pterodactylus.demoscenemusic.template;
+
+import java.util.Arrays;
+import java.util.List;
+import java.util.Map;
+
+import net.pterodactylus.util.number.Numbers;
+import net.pterodactylus.util.template.Filter;
+import net.pterodactylus.util.template.TemplateContext;
+
+/**
+ * {@link Filter} implementation that only shows the three most significant
+ * digits of a number, adding prefix for kilo (kibi, actually), mega (mebi), et
+ * cetera, as necessary.
+ *
+ * @author <a href="mailto:bombe@pterodactylus.net">David ‘Bombe’ Roden</a>
+ */
+public class ConciseNumberFilter implements Filter {
+
+	private static final List<String> prefixes = Arrays.asList("", "Ki", "Mi", "Gi", "Ti", "Pi", "Ei");
+
+	/**
+	 * {@inheritDoc}
+	 */
+	@Override
+	public Object format(TemplateContext templateContext, Object data, Map<String, Object> parameters) {
+		double number = Numbers.safeParseLong(data, 0L);
+		int prefix = 0;
+		while (number > 1023) {
+			prefix++;
+			number /= 1024.0;
+		}
+		if (number >= 1000) {
+			return String.format("%1.2f %s", number / 1024.0, prefixes.get(prefix + 1));
+		}
+		if (number >= 100) {
+			return String.format("%1.0f %s", number, prefixes.get(prefix));
+		}
+		if (number >= 10) {
+			return String.format("%1.1f %s", number, prefixes.get(prefix));
+		}
+		return String.format("%1.2f %s", number, prefixes.get(prefix));
+	}
+
+}
-- 
2.7.4