Export bytesNeeded

dingosky · dingosky · commit 3c05fa8576b7 · 2017-07-19T09:46:15.000-07:00
diff --git a/lib/entropy.js b/lib/entropy.js
@@ -48,22 +48,14 @@ const bitsWithPowers = (tPower, rPower) => {
 }
 
 const randomString = (bits, charSet) => {
-  if (!CharSet.isValid(charSet)) { throw new Error('Invalid CharSet') }
-  
-  const count = Math.ceil(bits / charSet.entropyPerChar)
-  if (count <= 0) { return '' }
-
-  const bytes = randomBytes(count, charSet)
-  
+  const bytes = cryptoBytes(bits, charSet)
   return randomStringWithBytes(bits, charSet, bytes)
 }
 
 const randomStringWithBytes = (bits, charSet, bytes) => {
   if (!CharSet.isValid(charSet)) {
-    console.log('WTF?')
     throw new Error('Invalid CharSet')
   }
-
   if (bits <= 0) { return '' }
   
   const count = Math.ceil(bits / charSet.entropyPerChar)
@@ -121,10 +113,17 @@ const randomStringWithBytes = (bits, charSet, bytes) => {
   return string
 }
 
-const randomBytes = (count, charSet) => {
+const bytesNeeded = (entropy, charSet) => {
+  if (!CharSet.isValid(charSet)) { throw new Error('Invalid CharSet') }
+  const count = Math.ceil(entropy / charSet.entropyPerChar)
+  if (count <= 0) { return 0 }
+
   const bytesPerSlice = charSet.entropyPerChar / 8
-  const bytesNeeded = Math.ceil(count * bytesPerSlice)
-  return Buffer.from(crypto.randomBytes(bytesNeeded))
+  return Math.ceil(count * bytesPerSlice)
+}
+
+const cryptoBytes = (entropy, charSet) => {
+  return Buffer.from(crypto.randomBytes(bytesNeeded(entropy, charSet)))
 }
 
 const ndx64 = (chunk, slice, bytes) => {
@@ -178,6 +177,7 @@ export default {
   bitsWithPowers        : bitsWithPowers,
   randomString          : randomString,
   randomStringWithBytes : randomStringWithBytes,
+  bytesNeeded           : bytesNeeded,
 
   charSet64: CharSet.charSet64,
   charSet32: CharSet.charSet32,
