Implement var_int_list

README.md

@@ -35,23 +35,11 @@ With the help of browserify `bitmessage` provides different implementations for
   - [ ] HMAC-SHA-256
 - [ ] Core structures
   - [x] var_int
-    - [x] encode
-    - [x] decode
-  - [ ] var_str
-    - [ ] encode
-    - [ ] decode
-  - [ ] var_int_list
-    - [ ] encode
-    - [ ] decode
+  - [x] var_str
+  - [x] var_int_list
   - [ ] inv_vect
-    - [ ] encode
-    - [ ] decode
   - [ ] net_addr
-    - [ ] encode
-    - [ ] decode
   - [ ] bitfield
-    - [ ] encode
-    - [ ] decode
 - [ ] High-level objects
   - [ ] Address
     - [x] encode
@@ -63,8 +51,7 @@ With the help of browserify `bitmessage` provides different implementations for
     - [ ] encode
     - [ ] decode
 - [x] WIF
-  - [x] encode
-  - [x] decode
+- [ ] POW
 - [ ] Parse PyBitmessage configs
   - [ ] decode keys.dat
   - [ ] decode knownnodes.dat

lib/index.js

@@ -12,6 +12,8 @@
  * platform and [node-int64](https://www.npmjs.com/package/node-int64)
  * for Browser. You may replace it with other library with the same API.
  */
+// TODO(Kagami): Find another JS implementation, it should be able to
+// operate with `uint64_t` not just store it.
 exports.Int64 = require("int64-native");
 /** Working with addresses. */
 exports.Address = require("./address");

lib/struct.js

@@ -35,6 +35,8 @@ var var_int = exports.var_int = {
         length = 5;
         break;
       case 255:
+        // TODO(Kagami): Should we still use native number if value is
+        // less than 2^53?
         var hi = buf.readUInt32BE(1);
         assert(hi !== 0, "Impractical var_int");
         var lo = buf.readUInt32BE(5);
@@ -120,6 +122,8 @@ exports.var_str = {
   decode: function(buf) {
     var decoded = var_int.decode(buf);
     var strLength = decoded.value;
+    // FIXME(Kagami): We will fail here if var_int value is bigger than
+    // 2^32. Though it will require ~4G of RAM so it's not that bad.
     // XXX(Kagami): Spec doesn't mention encoding, using UTF-8.
     var str = decoded.rest.slice(0, strLength).toString();
     var rest = decoded.rest.slice(strLength);
@@ -137,3 +141,43 @@ exports.var_str = {
     return Buffer.concat([var_int.encode(strBuf.length), strBuf]);
   },
 };
+
+/**
+ * var_int_list.
+ * @see {@link https://bitmessage.org/wiki/Protocol_specification#Variable_length_list_of_integers}
+ */
+exports.var_int_list = {
+  /**
+   * Decode var_int_list.
+   * @param {Buffer} buf - Buffer that starts with encoded var_int_list
+   * @return {{list: number[], length: number, rest: Buffer}}
+   * Decoded var_int_list structure.
+   */
+  decode: function(buf) {
+    var decoded = var_int.decode(buf);
+    var listLength = decoded.value;
+    // FIXME(Kagami): We will fail here if var_int value is bigger than
+    // 2^32. Though such list would require more than 4G of RAM so it's
+    // not that bad.
+    var list = new Array(listLength);
+    var rest = decoded.rest;
+    var sumLength = decoded.length;
+    for (var i = 0; i < listLength; i++) {
+      decoded = var_int.decode(rest);
+      list[i] = decoded.value;
+      rest = decoded.rest;
+      sumLength += decoded.length;
+    }
+    return {list: list, length: sumLength, rest: rest}
+  },
+
+  /**
+   * Encode list of numbers into var_int_list.
+   * @param {number[]} list - A number list
+   * @return {Buffer} Encoded var_int_list.
+   */
+  encode: function(list) {
+    var listBuf = Buffer.concat(list.map(var_int.encode));
+    return Buffer.concat([var_int.encode(list.length), listBuf]);
+  },
+};

test.js

@@ -9,6 +9,7 @@ var Address = bitmessage.Address;
 var wif = bitmessage.wif;
 var var_int = bitmessage.struct.var_int;
 var var_str = bitmessage.struct.var_str;
+var var_int_list = bitmessage.struct.var_int_list;
 var bmcrypto = require("./lib/crypto");
 
 describe("Core structures", function() {
@@ -61,15 +62,20 @@ describe("Core structures", function() {
   describe("var_str", function() {
     it("should decode", function() {
       var res;
+      res = var_str.decode(Buffer("00", "hex"));
+      expect(res.str).to.equal("");
+      expect(res.length).to.equal(1);
+      expect(res.rest.toString("hex")).to.equal("");
+
       res = var_str.decode(Buffer("0474657374", "hex"));
       expect(res.str).to.equal("test");
       expect(res.length).to.equal(5);
       expect(res.rest.toString("hex")).to.equal("");
 
-      res = var_str.decode(Buffer("00", "hex"));
-      expect(res.str).to.equal("");
-      expect(res.length).to.equal(1);
-      expect(res.rest.toString("hex")).to.equal("");
+      res = var_str.decode(Buffer("0474657374ffffff", "hex"));
+      expect(res.str).to.equal("test");
+      expect(res.length).to.equal(5);
+      expect(res.rest.toString("hex")).to.equal("ffffff");
     });
 
     it("should encode", function() {
@@ -77,6 +83,36 @@ describe("Core structures", function() {
       expect(var_str.encode("").toString("hex")).to.equal("00");
     });
   });
+
+  describe("var_int_list", function() {
+    it("should decode", function() {
+      var res;
+      res = var_int_list.decode(Buffer("00", "hex"));
+      expect(res.list).to.deep.equal([]);
+      expect(res.length).to.equal(1);
+      expect(res.rest.toString("hex")).to.equal("");
+
+      res = var_int_list.decode(Buffer("0501fd0400ff0004000000000000fd9c40fe000186a0", "hex"));
+      expect(res.length).to.equal(22);
+      expect(res.list.length).to.equal(5);
+      expect(res.list[0]).to.equal(1);
+      expect(res.list[1]).to.equal(1024);
+      expect(res.list[2] == 1125899906842624).to.be.true;
+      expect(res.list[3]).to.equal(40000);
+      expect(res.list[4]).to.equal(100000);
+      expect(res.rest.toString("hex")).to.equal("");
+
+      res = var_int_list.decode(Buffer("0501fd0400ff0004000000000000fd9c40fe000186a0ffffff", "hex"));
+      expect(res.length).to.equal(22);
+      expect(res.list.length).to.equal(5);
+      expect(res.rest.toString("hex")).to.equal("ffffff");
+    });
+
+    it("should encode", function() {
+      expect(var_int_list.encode([]).toString("hex")).to.equal("00");
+      expect(var_int_list.encode([1, 1024, 1125899906842624, 40000, 100000]).toString("hex")).to.equal("0501fd0400ff0004000000000000fd9c40fe000186a0");
+    });
+  });
 });
 
 describe("WIF", function() {