Currency: Add support for complex currencies. (UInt160)

This patch might regress the performance of the Currency class and by extension
the Amount class. Since Amount is on a lot of hot paths in the client we should
make sure this isn't a major problem.

As for compatibility, this patch is a major change, but it should maintain the
public interface very well, which the exception of some strange edge cases (e.g.
Currency.from_json(1337)), which weren't well-defined before anyway. Any code
that accesses _value directly (shame on you!) will need to be fixed. There
aren't any such references in ripple-client or the rippled test suite, so I
think we're looking pretty good.

src/js/ripple/amount.js

@@ -628,7 +628,7 @@ Amount.prototype.parse_json = function (j) {
   switch (typeof j) {
     case 'string':
       // .../.../... notation is not a wire format.  But allowed for easier testing.
-      var m = j.match(/^([^/]+)\/(...)(?:\/(.+))?$/);
+      var m = j.match(/^([^/]+)\/([^/]+)(?:\/(.+))?$/);
 
       if (m) {
         this._currency  = Currency.from_json(m[2]);
@@ -655,7 +655,7 @@ Amount.prototype.parse_json = function (j) {
         j.copyTo(this);
       } else if (j.hasOwnProperty('value')) {
         // Parse the passed value to sanitize and copy it.
-        this._currency.parse_json(j.currency); // Never XRP.
+        this._currency.parse_json(j.currency, true); // Never XRP.
 
         if (typeof j.issuer === 'string') {
           this._issuer.parse_json(j.issuer);

src/js/ripple/currency.js

@@ -1,10 +1,14 @@
 
+var extend    = require('extend');
+
+var UInt160 = require('./uint160').UInt160;
+var utils = require('./utils');
+
 //
 // Currency support
 //
 
-// XXX Internal form should be UInt160.
-function Currency() {
+var Currency = extend(function () {
   // Internal form: 0 = XRP. 3 letter-code.
   // XXX Internal should be 0 or hex with three letter annotation when valid.
 
@@ -14,72 +18,63 @@ function Currency() {
   // XXX Should support hex, C++ doesn't currently allow it.
 
   this._value  = NaN;
-};
+}, UInt160);
 
-// Given "USD" return the json.
-Currency.json_rewrite = function (j) {
-  return Currency.from_json(j).to_json();
-};
+Currency.prototype = extend({}, UInt160.prototype);
+Currency.prototype.constructor = Currency;
 
-Currency.from_json = function (j) {
-  return j instanceof Currency ? j.clone() : new Currency().parse_json(j);
-};
+Currency.HEX_CURRENCY_BAD = "0000000000000000000000005852500000000000";
 
-Currency.from_bytes = function (j) {
-  return j instanceof Currency ? j.clone() : new Currency().parse_bytes(j);
-};
-
-Currency.is_valid = function (j) {
-  return Currency.from_json(j).is_valid();
-};
-
-Currency.prototype.clone = function() {
-  return this.copyTo(new Currency());
-};
-
-// Returns copy.
-Currency.prototype.copyTo = function (d) {
-  d._value = this._value;
-  return d;
-};
-
-Currency.prototype.equals = function (d) {
-  var equals = (typeof this._value !== 'string' && isNaN(this._value))
-    || (typeof d._value !== 'string' && isNaN(d._value));
-  return equals ? false: this._value === d._value;
+Currency.from_json = function (j, shouldInterpretXrpAsIou) {
+  if (j instanceof this) {
+    return j.clone();
+  } else {
+    return (new this()).parse_json(j, shouldInterpretXrpAsIou);
+  }
 };
 
 // this._value = NaN on error.
-Currency.prototype.parse_json = function (j) {
-  var result = NaN;
+Currency.prototype.parse_json = function (j, shouldInterpretXrpAsIou) {
+  this._value = NaN;
 
   switch (typeof j) {
     case 'string':
       if (!j || /^(0|XRP)$/.test(j)) {
-        result = 0;
+        if (shouldInterpretXrpAsIou) {
+          this.parse_hex(Currency.HEX_CURRENCY_BAD);
+        } else {
+          this.parse_hex(Currency.HEX_ZERO);
+        }
       } else if (/^[a-zA-Z0-9]{3}$/.test(j)) {
-        result = j;
+        var currencyCode = j.toUpperCase();
+        var currencyData = utils.arraySet(20, 0);
+        currencyData[12] = currencyCode.charCodeAt(0) & 0xff;
+        currencyData[13] = currencyCode.charCodeAt(1) & 0xff;
+        currencyData[14] = currencyCode.charCodeAt(2) & 0xff;
+        this.parse_bytes(currencyData);
+      } else {
+        this.parse_hex(j);
       }
       break;
 
     case 'number':
       if (!isNaN(j)) {
-        result = j;
+        this.parse_number(j);
       }
       break;
 
     case 'object':
       if (j instanceof Currency) {
-        result = j.copyTo({})._value;
+        this._value = j.copyTo({})._value;
       }
       break;
   }
 
-  this._value = result;
-
   return this;
 };
 
+// XXX Probably not needed anymore?
+/*
 Currency.prototype.parse_bytes = function (byte_array) {
   if (Array.isArray(byte_array) && byte_array.length === 20) {
     var result;
@@ -110,21 +105,62 @@ Currency.prototype.parse_bytes = function (byte_array) {
   }
   return this;
 };
+*/
 
 Currency.prototype.is_native = function () {
-  return !isNaN(this._value) && !this._value;
+  return !isNaN(this._value) && this.is_zero();
 };
 
-Currency.prototype.is_valid = function () {
-  return typeof this._value === 'string' || !isNaN(this._value);
-};
+// XXX Currently we inherit UInt.prototype.is_valid, which is mostly fine.
+//
+//     We could be doing further checks into the internal format of the
+//     currency data, since there are some values that are invalid.
+//
+//Currency.prototype.is_valid = function () {
+//  return this._value instanceof BigInteger && ...;
+//};
 
 Currency.prototype.to_json = function () {
-  return this._value ? this._value : "XRP";
+  var bytes = this.to_bytes();
+
+  // is it 0 everywhere except 12, 13, 14?
+  var isZeroExceptInStandardPositions = true;
+
+  if (!bytes) {
+    return "XRP";
+  }
+
+  for (var i=0; i<20; i++) {
+    isZeroExceptInStandardPositions = isZeroExceptInStandardPositions && (i===12 || i===13 || i===14 || bytes[i]===0);
+  }
+
+  if (isZeroExceptInStandardPositions) {
+    var currencyCode = String.fromCharCode(bytes[12])
+                     + String.fromCharCode(bytes[13])
+                     + String.fromCharCode(bytes[14]);
+    if (/^[A-Z0-9]{3}$/.test(currencyCode) && currencyCode !== "XRP" ) {
+      return currencyCode;
+    } else if (currencyCode === "\0\0\0") {
+      return "XRP";
+    } else {
+      return "XRP";
+    }
+  } else {
+    var currencyHex = this.to_hex();
+
+    // XXX This is to maintain backwards compatibility, but it is very, very odd
+    //     behavior, so we should deprecate it and get rid of it as soon as
+    //     possible.
+    if (currencyHex === Currency.HEX_ONE) {
+      return 1;
+    }
+
+    return currencyHex;
+  }
 };
 
 Currency.prototype.to_human = function () {
-  return this._value ? this._value : "XRP";
+  return this.to_json();
 };
 
 exports.Currency = Currency;

src/js/ripple/serializedtypes.js

@@ -280,22 +280,13 @@ STHash160.id = 17;
 // Internal
 var STCurrency = new SerializedType({
   serialize: function (so, val, xrp_as_ascii) {
-    var currency = val.to_json().toUpperCase();
+    var currencyData = val.to_bytes();
 
-    if (!isCurrencyString(currency)) {
+    if (!currencyData) {
       throw new Error('Tried to serialize invalid/unimplemented currency type.');
     }
 
-    if (currency === 'XRP' && !xrp_as_ascii) {
-      serialize_hex(so, UInt160.HEX_ZERO, true);
-    } else {
-      var currencyCode = currency.toUpperCase();
-      var currencyData = utils.arraySet(20, 0);
-      currencyData[12] = currencyCode.charCodeAt(0) & 0xff;
-      currencyData[13] = currencyCode.charCodeAt(1) & 0xff;
-      currencyData[14] = currencyCode.charCodeAt(2) & 0xff;
     so.append(currencyData);
-    }
   },
   parse: function (so) {
     var bytes = so.read(20);
@@ -484,8 +475,8 @@ var STPathSet = exports.PathSet = new SerializedType({
         }
 
         if (entry.currency) {
-          var currency = Currency.from_json(entry.currency);
-          STCurrency.serialize(so, currency, entry.non_native);
+          var currency = Currency.from_json(entry.currency, entry.non_native);
+          STCurrency.serialize(so, currency);
         }
 
         if (entry.issuer) {
@@ -544,7 +535,8 @@ var STPathSet = exports.PathSet = new SerializedType({
         }
         if (tag_byte & this.typeIssuer) {
           //console.log('entry.issuer');
-          entry.issuer = STHash160.parse(so); //should know to use Base58?
+          entry.issuer = STHash160.parse(so);
+          // Enable and set correct type of base-58 encoding
           entry.issuer.set_version(Base.VER_ACCOUNT_ID);
           //console.log('DONE WITH ISSUER!');
         }

src/js/ripple/uint.js

@@ -75,6 +75,15 @@ UInt.from_bn = function (j) {
   }
 };
 
+// Return a new UInt from j.
+UInt.from_number = function (j) {
+  if (j instanceof this) {
+    return j.clone();
+  } else {
+    return (new this()).parse_number(j);
+  }
+};
+
 UInt.is_valid = function (j) {
   return this.from_json(j).is_valid();
 };
@@ -192,6 +201,19 @@ UInt.prototype.parse_bn = function (j) {
   return this;
 };
 
+UInt.prototype.parse_number = function (j) {
+  this._value = NaN;
+
+  if ("number" === typeof j &&
+      j === +j &&
+      j > 0) {
+    // XXX Better, faster way to get BigInteger from JS int?
+    this._value = new BigInteger(""+j);
+  }
+
+  return this;
+};
+
 // Convert from internal form.
 UInt.prototype.to_bytes = function () {
   if (!(this._value instanceof BigInteger))

test/currency-test.js

@@ -19,8 +19,8 @@ describe('Currency', function() {
     });
     it('from_json("XRP").to_json() == "XRP"', function() {
       var r = currency.from_json('XRP');
-      assert.strictEqual(0, r._value);
       assert(r.is_valid());
+      assert(r.is_native());
       assert.strictEqual('XRP', r.to_json());
     });
   });

test/serializedtypes-test.js

@@ -531,6 +531,16 @@ describe('Serialized types', function() {
       });
       assert.strictEqual(so.to_hex(), 'D5438D7EA4C680000000000000000000000000005852500000000000E4FE687C90257D3D2D694C8531CDEECBE84F3367');
     });
+    // Test support for 20-byte hex raw currency codes
+    it('Serialize 15/015841551A748AD23FEFFFFFFFEA028000000000/1', function () {
+      var so = new SerializedObject();
+      types.Amount.serialize(so, {
+        "value":"1000",
+        "currency":"015841551A748AD23FEFFFFFFFEA028000000000",
+        "issuer":"rM1oqKtfh1zgjdAgbFmaRm3btfGBX25xVo"
+      });
+      assert.strictEqual(so.to_hex(), 'D5438D7EA4C68000015841551A748AD23FEFFFFFFFEA028000000000E4FE687C90257D3D2D694C8531CDEECBE84F3367');
+    });
     it('Parse 1 XRP', function () {
       var so = new SerializedObject('4000000000000001');
       assert.strictEqual(types.Amount.parse(so).to_json(), '1');