From 7dc09e2e8df1da93c22f99043743cc98aa64d150 Mon Sep 17 00:00:00 2001
From: Thaddee Tyl <thaddee.tyl@gmail.com>
Date: Tue, 5 Apr 2016 22:21:23 +0200
Subject: [PATCH] Added dotted-version comparator & latest version

As planned in
https://github.com/badges/shields/issues/490#issuecomment-205550621.

Fixes #490.
---
 server.js | 60 ++++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 40 insertions(+), 20 deletions(-)

diff --git a/server.js b/server.js
index 13eab15..0a71903 100644
--- a/server.js
+++ b/server.js
@@ -5245,27 +5245,52 @@ function versionColor(version) {
   }
 }
 
+// Take string versions.
+// -1 if v1 < v2, 1 if v1 > v2, 0 otherwise.
+function compareDottedVersion(v1, v2) {
+  var parts1 = /([0-9\.]+)(.*)$/.exec(v1);
+  var parts2 = /([0-9\.]+)(.*)$/.exec(v2);
+  if (parts1 != null && parts2 != null) {
+    var numbers1 = parts1[1];
+    var numbers2 = parts2[1];
+    var distinguisher1 = parts1[2];
+    var distinguisher2 = parts2[2];
+    var numlist1 = numbers1.split('.').map(function(e) { return +e; });
+    var numlist2 = numbers2.split('.').map(function(e) { return +e; });
+    var cmp = listCompare(numlist1, numlist2);
+    if (cmp !== 0) { return cmp; }
+    else { return distinguisher1 < distinguisher2? -1:
+                  distinguisher1 > distinguisher2? 1: 0; }
+  }
+  return v1 < v2? -1: v1 > v2? 1: 0;
+}
+
+// Take a list of string versions.
+// Return the latest, or undefined, if there are none.
+function latestDottedVersion(versions) {
+  var len = versions.length;
+  if (len === 0) { return; }
+  var version = versions[0];
+  for (var i = 1; i < len; i++) {
+    if (compareDottedVersion(version, versions[i]) < 0) {
+      version = versions[i];
+    }
+  }
+  return version;
+}
+
 // Given a list of versions (as strings), return the latest version.
+// Return undefined if no version could be found.
 function latestVersion(versions) {
   var version = '';
   var origVersions = versions;
   versions = versions.filter(function(version) {
     return (/^v?[0-9]/).test(version);
   });
-  semver_versions = versions.map(function(version) {
-    var matches = /^(v?[0-9]+)(\.[0-9]+)?(-.*)?$/.exec(version);
-    if (matches) {
-      version = matches[1] + (matches[2] ? matches[2] : '.0') + '.0' +
-        (matches[3] ? matches[3] : '');
-    }
-    return version;
-  });
   try {
-    version = semver.maxSatisfying(semver_versions, '');
-    version = versions[semver_versions.indexOf(version)];
+    version = semver.maxSatisfying(versions, '');
   } catch(e) {
-    versions = versions.sort();
-    version = versions[versions.length - 1];
+    version = latestDottedVersion(versions);
   }
   if (version === undefined) {
     origVersions = origVersions.sort();
@@ -5381,20 +5406,15 @@ function phpNumberedVersionData(version) {
 }
 
 function listCompare(a, b) {
-  for (var i = 0; i < a.length; i++) {
+  var alen = a.length, blen = b.length;
+  for (var i = 0; i < alen; i++) {
     if (a[i] < b[i]) {
       return -1;
     } else if (a[i] > b[i]) {
       return 1;
     }
   }
-  if (a.length < b.length) {
-    return -1;
-  } else if (a.length > b.length) {
-    return 1;
-  } else {
-    return 0;
-  }
+  return alen - blen;
 }
 
 // Return a negative value if v1 < v2,