From dcacd5e11bf27eca1bfa1af644cee1dc5f7991bb Mon Sep 17 00:00:00 2001
From: Christopher Jeffrey <chjjeffrey@gmail.com>
Date: Thu, 28 Apr 2016 23:21:18 -0700
Subject: [PATCH] more accurate fee calculation.

---
 lib/bcoin/mtx.js | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/lib/bcoin/mtx.js b/lib/bcoin/mtx.js
index f233ab8f..95affd97 100644
--- a/lib/bcoin/mtx.js
+++ b/lib/bcoin/mtx.js
@@ -870,7 +870,8 @@ MTX.prototype.isScripted = function isScripted() {
  */
 
 MTX.prototype.maxSize = function maxSize(options, force) {
-  var i, j, input, total, size, prev, m, n;
+  var scale = constants.WITNESS_SCALE_FACTOR;
+  var i, j, input, total, size, prev, m, n, sz;
   var witness, hadWitness, redeem, wallet;
 
   if (!force && this.isScripted())
@@ -924,8 +925,9 @@ MTX.prototype.maxSize = function maxSize(options, force) {
 
       if (redeem) {
         prev = redeem;
-        size += utils.sizePush(prev.getSize());
-        size += prev.getSize();
+        sz = prev.getSize();
+        size += utils.sizePush(sz);
+        size += sz;
       }
     }
 
@@ -950,8 +952,9 @@ MTX.prototype.maxSize = function maxSize(options, force) {
 
         if (redeem) {
           prev = redeem;
-          size += utils.sizePush(prev.getSize());
-          size += prev.getSize();
+          sz = prev.getSize();
+          size += utils.sizeVarint(sz);
+          size += sz;
         }
       } else if (prev.isWitnessPubkeyhash()) {
         prev = Script.createPubkeyhash(prev.code[1]);
@@ -1019,7 +1022,7 @@ MTX.prototype.maxSize = function maxSize(options, force) {
     if (witness) {
       // Add one byte back for the 0-byte input script.
       size += 1 * 4;
-      size = (size + 3) / 4 | 0;
+      size = (size + scale - 1) / scale | 0;
     }
 
     total += size;