From ec21986062c88f8251f7fbd7d493729405fdc2e0 Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Tue, 17 May 2016 12:47:16 -0700
Subject: [PATCH] optimize getProof. misc.

---
 lib/bcoin/block.js      |  3 ++-
 lib/bcoin/chainentry.js | 16 ++++++++++++++--
 lib/bcoin/mempool.js    | 16 ++++++++++------
 lib/bcoin/utils.js      | 12 ++++++------
 lib/bcoin/workers.js    |  5 +++++
 scripts/gen.js          |  2 +-
 6 files changed, 38 insertions(+), 16 deletions(-)

diff --git a/lib/bcoin/block.js b/lib/bcoin/block.js
index 44fbff26..894f1194 100644
--- a/lib/bcoin/block.js
+++ b/lib/bcoin/block.js
@@ -481,7 +481,8 @@ Block.reward = function reward(height, network) {
   network = bcoin.network.get(network);
   halvings = height / network.halvingInterval | 0;
 
-  // BIP 42
+  // BIP 42 (not technically necessary since we
+  // don't suffer from the undefined behavior of C++).
   // https://github.com/bitcoin/bips/blob/master/bip-0042.mediawiki
   if (halvings >= 64)
     return 0;
diff --git a/lib/bcoin/chainentry.js b/lib/bcoin/chainentry.js
index 016adf1f..2a1b3043 100644
--- a/lib/bcoin/chainentry.js
+++ b/lib/bcoin/chainentry.js
@@ -59,6 +59,13 @@ function ChainEntry(chain, data, prev) {
   this.chainwork = data.chainwork || this.getChainwork(prev);
 }
 
+/**
+ * The max chainwork (1 << 256).
+ * @const {BN}
+ */
+
+ChainEntry.MAX_CHAINWORK = new bn(1).ushln(256);
+
 /**
  * Calculate the proof: (1 << 256) / (target + 1)
  * @returns {BN} proof
@@ -68,7 +75,7 @@ ChainEntry.prototype.getProof = function getProof() {
   var target = utils.fromCompact(this.bits);
   if (target.isNeg() || target.cmpn(0) === 0)
     return new bn(0);
-  return new bn(1).ushln(256).div(target.addn(1));
+  return ChainEntry.MAX_CHAINWORK.div(target.iaddn(1));
 };
 
 /**
@@ -78,7 +85,12 @@ ChainEntry.prototype.getProof = function getProof() {
  */
 
 ChainEntry.prototype.getChainwork = function getChainwork(prev) {
-  return (prev ? prev.chainwork : new bn(0)).add(this.getProof());
+  var proof = this.getProof();
+
+  if (!prev)
+    return proof;
+
+  return proof.iadd(prev.chainwork);
 };
 
 /**
diff --git a/lib/bcoin/mempool.js b/lib/bcoin/mempool.js
index 88a53adf..b0eb00cb 100644
--- a/lib/bcoin/mempool.js
+++ b/lib/bcoin/mempool.js
@@ -1817,13 +1817,13 @@ MempoolEntry.fromTX = function fromTX(tx, height) {
  * can still be parsed as a regular tx since
  * the mempool entry data comes after the
  * serialized transaction.
- * @param {TX} tx
- * @param {Number} height - Entry height.
- * @returns {MempoolEntry}
+ * @param {BufferWriter?} writer
+ * @returns {Buffer}
  */
 
-MempoolEntry.prototype.toRaw = function toRaw() {
-  var p = new BufferWriter();
+MempoolEntry.prototype.toRaw = function toRaw(writer) {
+  var p = new BufferWriter(writer);
+
   bcoin.protocol.framer.renderTX(this.tx, true, p);
   p.writeU32(this.height);
   p.writeDouble(this.priority);
@@ -1832,7 +1832,11 @@ MempoolEntry.prototype.toRaw = function toRaw() {
   p.writeU32(this.count);
   p.writeU32(this.size);
   p.writeVarint(this.fees);
-  return p.render();
+
+  if (!writer)
+    p = p.render();
+
+  return p;
 };
 
 /**
diff --git a/lib/bcoin/utils.js b/lib/bcoin/utils.js
index 5ee2791f..2aec0c82 100644
--- a/lib/bcoin/utils.js
+++ b/lib/bcoin/utils.js
@@ -1966,15 +1966,15 @@ utils.write64 = function write64(dst, num, off) {
   off = off >>> 0;
 
   if (num.isNeg())
-    num = num.neg().notn(64).addn(1);
+    num = num.neg().inotn(64).iaddn(1);
 
   if (num.bitLength() > 64)
     num = num.uand(utils.U64);
 
-  num = num.toBuffer('le', 8);
+  num = num.toArray('le', 8);
 
   for (i = 0; i < num.length; i++)
-    dst[off++] = num[i] & 0xff;
+    dst[off++] = num[i];
 
   return 8;
 };
@@ -1996,15 +1996,15 @@ utils.write64BE = function write64BE(dst, num, off) {
   off = off >>> 0;
 
   if (num.isNeg())
-    num = num.neg().notn(64).addn(1);
+    num = num.neg().inotn(64).iaddn(1);
 
   if (num.bitLength() > 64)
     num = num.uand(utils.U64);
 
-  num = num.toBuffer('be', 8);
+  num = num.toArray('be', 8);
 
   for (i = 0; i < num.length; i++)
-    dst[off++] = num[i] & 0xff;
+    dst[off++] = num[i];
 
   return 8;
 };
diff --git a/lib/bcoin/workers.js b/lib/bcoin/workers.js
index 84c793c7..bc0bdfb5 100644
--- a/lib/bcoin/workers.js
+++ b/lib/bcoin/workers.js
@@ -701,6 +701,9 @@ Framer.item = function _item(item, p) {
         } else if (item instanceof bcoin.chainentry) {
           p.writeU8(43);
           item.toRaw(p);
+        } else if (item instanceof bcoin.mempoolentry) {
+          p.writeU8(44);
+          item.toRaw(p);
         } else if (bn.isBN(item)) {
           p.writeU8(50);
           p.writeVarBytes(item.toBuffer());
@@ -859,6 +862,8 @@ Parser.parseItem = function parseItem(p) {
       return bcoin.coin.fromExtended(p);
     case 43:
       return bcoin.chainentry.fromRaw(null, p);
+    case 43:
+      return bcoin.mempoolentry.fromRaw(p);
     case 50:
       return new bn(p.readVarBytes());
     default:
diff --git a/scripts/gen.js b/scripts/gen.js
index 75504f6a..0def9546 100644
--- a/scripts/gen.js
+++ b/scripts/gen.js
@@ -26,7 +26,7 @@ function createGenesisBlock(options) {
   }
 
   if (!options.reward)
-    options.reward = new bn(50).mul(constants.COIN);
+    options.reward = 50 * constants.COIN;
 
   tx = {
     version: 1,