From 353937e3a176fd86ed8c0f07a868cea750219760 Mon Sep 17 00:00:00 2001
From: "Felix W. Dekker" <felix@fwdekker.com>
Date: Sun, 5 Apr 2020 13:03:44 +0200
Subject: [PATCH] Fix base64 encoding

Fixes #9.
---
 index.html | 30 ++++++++++++++++++++++++++++--
 1 file changed, 28 insertions(+), 2 deletions(-)

diff --git a/index.html b/index.html
index 29b6f98..e9144b9 100644
--- a/index.html
+++ b/index.html
@@ -55,7 +55,7 @@
             <a href="https://git.fwdekker.com/FWDekker/converter/src/branch/master/LICENSE">MIT License</a>.
             Source code available on <a href="https://git.fwdekker.com/FWDekker/converter/">git</a>.
 
-            <div style="float: right;">v1.4.3</div>
+            <div style="float: right;">v1.4.4</div>
         </section>
     </footer>
 </main>
@@ -132,6 +132,32 @@
         }
     }
 
+    class Base64NumeralSystem extends NumeralSystem {
+        constructor(alphabet) {
+            super(64, alphabet, true);
+        }
+
+
+        decimalToBase(decimalNumber) {
+            const hex = decimalNumber.toString(16);
+            const b64 = Array.from(hex.padStart(hex.length + hex.length % 2))
+                .reduce((result, value, index, array) => {
+                    if (index % 2 === 0) result.push(array.slice(index, index + 2));
+                    return result;
+                }, [])
+                .map(pair => String.fromCharCode(parseInt(pair.join(""), 16)))
+                .join("");
+
+            return btoa(b64);
+        }
+
+        baseToDecimal(baseString) {
+            const hex = Array.from(atob(baseString))
+                .map(char => char.charCodeAt(0).toString(16).padStart(2, "0")).join("");
+            return bigInt(hex, 16);
+        }
+    }
+
     class Base64NumeralSystemInput extends NumeralSystemInput {
         // TODO Convert static methods to static properties once supported by Firefox
         static defaultAlphabet() {
@@ -144,7 +170,7 @@
 
 
         constructor(name) {
-            super(name, new NumeralSystem(64, Base64NumeralSystemInput.defaultAlphabet(), true));
+            super(name, new Base64NumeralSystem(Base64NumeralSystemInput.defaultAlphabet()));
 
             this.dropdownLabel = document.createElement("label");
             this.dropdownLabel.setAttribute("for", `${this.name}Dropdown`);