optimize readVarint.

README.md

@@ -25,9 +25,15 @@ Try it in the browser: http://bcoin.io/browser.html
 ## Install
 
 ```
-$ npm install bcoin
+$ git clone git://github.com/bcoin-org/bcoin.git
+$ cd bcoin
+$ npm install
 ```
 
+The latest BCoin has not been published to NPM yet, as it is still under fairly
+heavy development (which may involve changing serialization formats for the
+database).
+
 ## Documentation
 
 Read the docs here: http://bcoin.io/docs/
@@ -38,6 +44,7 @@ Read the docs here: http://bcoin.io/docs/
 - [Connecting to the P2P network](#connecting-to-the-p2p-network)
 - [Doing and SPV sync](#doing-an-spv-sync)
 - [High-level usage with the Node object](#high-level-usage-with-the-node-object)
+- [Running the default full node](#running-the-default-full-node)
 - [Running a full node in the browser](#running-a-full-node-in-the-browser)
 - [CLI Usage](#cli-usage)
 
@@ -336,6 +343,14 @@ node.chain.on('full', function() {
 });
 ```
 
+### Running the default full node
+
+``` bash
+$ node bin/node --fast
+```
+
+`--fast` will enable checkpoints, coin cache, and getheaders.
+
 ### Running a full node in the browser
 
 ``` bash

lib/bcoin/utils.js

@@ -1413,37 +1413,40 @@ utils.readVarint = function readVarint(data, off, big) {
 
   assert(off < data.length);
 
-  if (data[off] < 0xfd) {
+  switch (data[off]) {
-    size = 1;
+    case 0xff:
-    value = data[off];
+      size = 9;
-    if (big)
+      assert(off + size <= data.length);
-      value = new bn(value);
+      if (big) {
-  } else if (data[off] === 0xfd) {
+        value = utils.readU64(data, off + 1);
-    size = 3;
+        assert(value.bitLength() > 32);
-    assert(off + size <= data.length);
+      } else {
-    value = data[off + 1] | (data[off + 2] << 8);
+        value = utils.readU64N(data, off + 1);
-    assert(value >= 0xfd);
+        assert(value > 0xffffffff);
-    if (big)
+      }
-      value = new bn(value);
+      break;
-  } else if (data[off] === 0xfe) {
+    case 0xfe:
-    size = 5;
+      size = 5;
-    assert(off + size <= data.length);
+      assert(off + size <= data.length);
-    value = data.readUInt32LE(off + 1, true);
+      value = data.readUInt32LE(off + 1, true);
-    assert(value > 0xffff);
+      assert(value > 0xffff);
-    if (big)
+      if (big)
-      value = new bn(value);
+        value = new bn(value);
-  } else if (data[off] === 0xff) {
+      break;
-    size = 9;
+    case 0xfd:
-    assert(off + size <= data.length);
+      size = 3;
-    if (big) {
+      assert(off + size <= data.length);
-      value = utils.readU64(data, off + 1);
+      value = data[off + 1] | (data[off + 2] << 8);
-      assert(value.bitLength() > 32);
+      assert(value >= 0xfd);
-    } else {
+      if (big)
-      value = utils.readU64N(data, off + 1);
+        value = new bn(value);
-      assert(value > 0xffffffff);
+      break;
-    }
+    default:
-  } else {
+      size = 1;
-    assert(false, 'Malformed varint.');
+      value = data[off];
+      if (big)
+        value = new bn(value);
+      break;
   }
 
   return { size: size, value: value };