From 23945f54c31d47b022184bc2bca799ed33f0f927 Mon Sep 17 00:00:00 2001
From: Josh Wolfe <thejoshwolfe@gmail.com>
Date: Thu, 26 Mar 2015 18:47:46 -0700
Subject: [PATCH] slightly cleaner readPosition

---
 src/protocol.js | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/src/protocol.js b/src/protocol.js
index 2729ecc..5de8fe2 100644
--- a/src/protocol.js
+++ b/src/protocol.js
@@ -1095,18 +1095,23 @@ function readBool(buffer, offset) {
 }
 
 function readPosition(buffer, offset) {
-  var longVal = readLong(buffer, offset).value; // I wish I could do destructuring...
-  var x = longVal[0] >> 6;
-  if(x>33554432) x-=67108864;
-  var y = ((longVal[0] & 0x3F) << 6) | ((longVal[1] >> 26) & 0x3f);
-  if(y>2048) y-=4096;
-  var z = longVal[1] & 0x3FFFFFF;
-  if(z>33554432) z-=67108864;
+  var longVal = readLong(buffer, offset).value;
+  var x = signExtend26(longVal[0] >> 6);
+  var y = signExtend12(((longVal[0] & 0x3f) << 6) | ((longVal[1] >> 26) & 0x3f));
+  var z = signExtend26(longVal[1] & 0x3FFFFFF);
   return {
     value: { x: x, y: y, z: z },
     size: 8
   };
 }
+function signExtend26(value) {
+  if (value > 0x2000000) value -= 0x4000000;
+  return value;
+}
+function signExtend12(value) {
+  if (value > 0x800) value -= 0x1000;
+  return value;
+}
 
 function readSlot(buffer, offset) {
   var value = {};