Refactor

dingosky · dingosky · commit e3105372eed0 · 2017-08-10T08:32:24.000-07:00
entropyPerChar -&gt; bitsPerChar
diff --git a/lib/charSet.js b/lib/charSet.js
@@ -4,11 +4,11 @@ class CharSet {
   constructor(chars, ndxFn) {
     this.chars = chars
     this.ndxFn = ndxFn
-    this.entropyPerChar = Math.floor(Math.log2(chars.length))
-    if (this.entropyPerChar != Math.log2(chars.length)) {
+    this.bitsPerChar = Math.floor(Math.log2(chars.length))
+    if (this.bitsPerChar != Math.log2(chars.length)) {
       throw new Error('EntropyString only supports CharSets with a power of 2 characters')
     }
-    this.charsPerChunk = lcm(this.entropyPerChar, 8) / this.entropyPerChar
+    this.charsPerChunk = lcm(this.bitsPerChar, 8) / this.bitsPerChar
   }
 
   use(chars) {
@@ -54,28 +54,28 @@ const _ndx2 = (chunk, slice, bytes) => {
   return _ndxDiv(chunk, slice, bytes, 1)
 }
 
-const _ndxGen = (chunk, slice, bytes, entropyPerChar) => {
+const _ndxGen = (chunk, slice, bytes, bitsPerChar) => {
   let bitsPerByte = 8
-  let slicesPerChunk = lcm(entropyPerChar, bitsPerByte) / bitsPerByte
+  let slicesPerChunk = lcm(bitsPerChar, bitsPerByte) / bitsPerByte
   let bNum = chunk * slicesPerChunk
 
-  let rShift = bitsPerByte - entropyPerChar
-  let lOffset = Math.floor((slice*entropyPerChar)/bitsPerByte)
-  let lShift = (slice*entropyPerChar) % bitsPerByte
+  let rShift = bitsPerByte - bitsPerChar
+  let lOffset = Math.floor((slice*bitsPerChar)/bitsPerByte)
+  let lShift = (slice*bitsPerChar) % bitsPerByte
 
   let ndx = ((bytes[bNum+lOffset]<<lShift)&0xff)>>rShift
 
-  let rOffset = Math.ceil((slice*entropyPerChar)/bitsPerByte)
-  let rShiftIt = ((rOffset+1)*bitsPerByte - (slice+1)*entropyPerChar) % bitsPerByte
+  let rOffset = Math.ceil((slice*bitsPerChar)/bitsPerByte)
+  let rShiftIt = ((rOffset+1)*bitsPerByte - (slice+1)*bitsPerChar) % bitsPerByte
   if (rShift < rShiftIt) {
     ndx += bytes[bNum+rOffset]>>rShiftIt
   }
   return ndx
 }
 
-const _ndxDiv = (chunk, slice, bytes, entropyPerChar) => {
-  let lShift = entropyPerChar
-  let rShift = 8 - entropyPerChar
+const _ndxDiv = (chunk, slice, bytes, bitsPerChar) => {
+  let lShift = bitsPerChar
+  let rShift = 8 - bitsPerChar
   return ((bytes[chunk]<<(lShift*slice))&0xff)>>rShift
 }
 
diff --git a/lib/entropy.js b/lib/entropy.js
@@ -67,10 +67,10 @@ const stringWithBytes = (entropy, charSet, bytes) => {
   }
   if (entropy <= 0) { return '' }
 
-  const count = Math.ceil(entropy / charSet.entropyPerChar)
+  const count = Math.ceil(entropy / charSet.bitsPerChar)
   if (count <= 0) { return '' }
 
-  const needed = Math.ceil(count * (charSet.entropyPerChar / _bitsPerByte))
+  const needed = Math.ceil(count * (charSet.bitsPerChar / _bitsPerByte))
   if (bytes.length < needed) {
     throw new Error('Insufficient bytes')
   }
@@ -94,10 +94,10 @@ const stringWithBytes = (entropy, charSet, bytes) => {
 
 const bytesNeeded = (entropy, charSet) => {
   if (!CharSet.isValid(charSet)) { throw new Error('Invalid CharSet') }
-  const count = Math.ceil(entropy / charSet.entropyPerChar)
+  const count = Math.ceil(entropy / charSet.bitsPerChar)
   if (count <= 0) { return 0 }
 
-  const bytesPerSlice = charSet.entropyPerChar / _bitsPerByte
+  const bytesPerSlice = charSet.bitsPerChar / _bitsPerByte
   return Math.ceil(count * bytesPerSlice)
 }
 
diff --git a/test/charSet.js b/test/charSet.js
@@ -5,48 +5,48 @@ import CharSet from '../lib/charSet';
 test('char set 64', t => {
   const charSet = CharSet.charSet64
   t.is(charSet.chars.length, 64)
-  const entropyPerChar = Math.log2(charSet.chars.length)
-  t.is(charSet.entropyPerChar, entropyPerChar)
+  const bitsPerChar = Math.log2(charSet.chars.length)
+  t.is(charSet.bitsPerChar, bitsPerChar)
   t.is(charSet.charsPerChunk, 4)
 })
 
 test('char set 32', t => {
   const charSet = CharSet.charSet32
   t.is(charSet.chars.length, 32)
-  const entropyPerChar = Math.log2(charSet.chars.length)
-  t.is(charSet.entropyPerChar, entropyPerChar)
+  const bitsPerChar = Math.log2(charSet.chars.length)
+  t.is(charSet.bitsPerChar, bitsPerChar)
   t.is(charSet.charsPerChunk, 8)
 })
 
 test('char set 16', t => {
   const charSet = CharSet.charSet16
   t.is(charSet.chars.length, 16)
-  const entropyPerChar = Math.log2(charSet.chars.length)
-  t.is(charSet.entropyPerChar, entropyPerChar)
+  const bitsPerChar = Math.log2(charSet.chars.length)
+  t.is(charSet.bitsPerChar, bitsPerChar)
   t.is(charSet.charsPerChunk, 2)
 })
 
 test('char set 8', t => {
   const charSet = CharSet.charSet8
   t.is(charSet.chars.length, 8)
-  const entropyPerChar = Math.log2(charSet.chars.length)
-  t.is(charSet.entropyPerChar, entropyPerChar)
+  const bitsPerChar = Math.log2(charSet.chars.length)
+  t.is(charSet.bitsPerChar, bitsPerChar)
   t.is(charSet.charsPerChunk, 8)
 })
 
 test('char set 4', t => {
   const charSet = CharSet.charSet4
   t.is(charSet.chars.length, 4)
-  const entropyPerChar = Math.log2(charSet.chars.length)
-  t.is(charSet.entropyPerChar, entropyPerChar)
+  const bitsPerChar = Math.log2(charSet.chars.length)
+  t.is(charSet.bitsPerChar, bitsPerChar)
   t.is(charSet.charsPerChunk, 4)
 })
 
 test('char set 2', t => {
   const charSet = CharSet.charSet2
   t.is(charSet.chars.length, 2)
-  const entropyPerChar = Math.log2(charSet.chars.length)
-  t.is(charSet.entropyPerChar, entropyPerChar)
+  const bitsPerChar = Math.log2(charSet.chars.length)
+  t.is(charSet.bitsPerChar, bitsPerChar)
   t.is(charSet.charsPerChunk, 8)
 })
 
