init

node_modules/ripple-lib-transactionparser/src/quality.js

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+'use strict'
+var assert = require('assert')
+var BigNumber = require('bignumber.js')
+
+/*
+The quality, as stored in the last 64 bits of a directory index, is stored as
+the quotient of TakerPays/TakerGets. It uses drops (1e-6 XRP) for XRP values.
+*/
+
+function adjustQualityForXRP(quality, takerGetsCurrency, takerPaysCurrency) {
+  var numeratorShift = (takerPaysCurrency === 'XRP' ? -6 : 0)
+  var denominatorShift = (takerGetsCurrency === 'XRP' ? -6 : 0)
+  var shift = numeratorShift - denominatorShift
+  return shift === 0 ? (new BigNumber(quality)).toString() :
+    (new BigNumber(quality)).shiftedBy(shift).toString()
+}
+
+function parseQuality(qualityHex, takerGetsCurrency, takerPaysCurrency) {
+  assert(qualityHex.length === 16)
+  var mantissa = new BigNumber(qualityHex.substring(2), 16)
+  var offset = parseInt(qualityHex.substring(0, 2), 16) - 100
+  var quality = mantissa.toString() + 'e' + offset.toString()
+  return adjustQualityForXRP(quality, takerGetsCurrency, takerPaysCurrency)
+}
+
+module.exports = parseQuality