Add "To Base58" and "From Base58" operations

src/js/operations/Base58.js

@@ -0,0 +1,136 @@
+/**
+ * Base64 operations.
+ *
+ * @author tlwr [toby@toby.codes]
+ * @copyright Crown Copyright 2017
+ * @license Apache-2.0
+ *
+ * @namespace
+ */
+var Base58 = {
+
+
+    /**
+     * @constant
+     * @default
+     */
+    ALPHABET_OPTIONS: [
+        {
+            name: "Bitcoin",
+            value: "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz",
+        },
+        {
+            name: "Ripple",
+            value: "rpshnaf39wBUDNEGHJKLM4PQRST7VWXYZ2bcdeCg65jkm8oFqi1tuvAxyz",
+        },
+    ],
+
+
+    /**
+     * @constant
+     * @default
+     */
+    REMOVE_NON_ALPH_CHARS: true,
+
+
+    /**
+     * To Base58 operation.
+     *
+     * @param {byteArray} input
+     * @param {Object[]} args
+     * @returns {string}
+     */
+    runTo: function(input, args) {
+        var alphabet = args[0] || Base58.ALPHABET_OPTIONS[0].value;
+
+        if (alphabet.length !== 58 ||
+            [].unique.call(alphabet).length !== 58) {
+            throw ("Error: alphabet must be of length 58");
+        }
+
+        if (input.length === 0) return "";
+
+        var result = [0];
+
+        input.forEach(function(b) {
+            var carry = (result[0] << 8) + b;
+            result[0] = carry % 58;
+            carry = (carry / 58) | 0;
+
+            for (var i = 1; i < result.length; i++) {
+                carry += result[i] << 8;
+                result[i] = carry % 58;
+                carry = (carry / 58) | 0;
+            }
+
+            while (carry > 0) {
+                result.push(carry % 58);
+                carry = (carry / 58) | 0;
+            }
+        });
+
+        result = result.map(function(b) {
+            return alphabet[b];
+        }).reverse().join("");
+
+        while (result.length < input.length) {
+            result = alphabet[0] + result;
+        }
+
+        return result;
+    },
+
+
+    /**
+     * From Base58 operation.
+     *
+     * @param {string} input
+     * @param {Object[]} args
+     * @returns {byteArray}
+     */
+    runFrom: function(input, args) {
+        var alphabet = args[0] || Base58.ALPHABET_OPTIONS[0].value;
+
+        if (alphabet.length !== 58 ||
+            [].unique.call(alphabet).length !== 58) {
+            throw ("Alphabet must be of length 58");
+        }
+
+        var removeNonAlphaChars = args[1];
+        if (removeNonAlphaChars === undefined)
+            removeNonAlphaChars = true;
+
+        if (input.length === 0) return [];
+
+        var result = [0];
+
+        [].forEach.call(input, function(c, charIndex) {
+            var index = alphabet.indexOf(c);
+
+            if (index === -1) {
+                if (removeNonAlphaChars) {
+                    return;
+                } else {
+                    throw ("Char " + c + " not in alphabet");
+                }
+            }
+
+            var carry = result[0] * 58 + index;
+            result[0] = carry & 0xFF;
+            carry = carry >> 8;
+
+            for (var i = 1; i < result.length; i++) {
+                carry += result[i] * 58;
+                result[i] = carry & 0xFF;
+                carry = carry >> 8;
+            }
+
+            while (carry > 0) {
+                result.push(carry & 0xFF);
+                carry = carry >> 8;
+            }
+        });
+
+        return result.reverse();
+    },
+};