From fb8eefd00d3f44af6e5bddf2856623350ed9fdf4 Mon Sep 17 00:00:00 2001
From: Chris Clark <clark@ripple.com>
Date: Wed, 8 Jul 2015 12:51:49 -0700
Subject: [PATCH] Refactor to make quality adjustment for XRP more clear

---
 src/api/ledger/parse/utils.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/api/ledger/parse/utils.js b/src/api/ledger/parse/utils.js
index 3c84a269..fb7f489d 100644
--- a/src/api/ledger/parse/utils.js
+++ b/src/api/ledger/parse/utils.js
@@ -8,8 +8,11 @@ const BigNumber = require('bignumber.js');
 
 function adjustQualityForXRP(quality: string, takerGetsCurrency: string,
     takerPaysCurrency: string) {
-  const shift = (takerGetsCurrency === 'XRP' ? 6 : 0)
-              - (takerPaysCurrency === 'XRP' ? 6 : 0);
+  // quality = takerPays.value/takerGets.value
+  // using drops (1e-6 XRP) for XRP values
+  const numeratorShift = (takerPaysCurrency === 'XRP' ? -6 : 0);
+  const denominatorShift = (takerGetsCurrency === 'XRP' ? -6 : 0);
+  const shift = numeratorShift - denominatorShift;
   return shift === 0 ? quality :
     (new BigNumber(quality)).shift(shift).toString();
 }