Resolve some magic numbers

dingosky · dingosky · commit a144ba5595c5 · 2017-07-14T15:05:17.000-07:00
diff --git a/EntropyString.podspec b/EntropyString.podspec
@@ -3,21 +3,15 @@
 Pod::Spec.new do |s|
   s.name         = "EntropyString"
   s.version      = "0.5.1"
-  s.summary      = "Efficiently generate secure, random strings of specified entropy from various character sets."
+  s.summary      = "Efficiently generate cryptographically strong random strings of specified entropy from various character sets."
 
-  # This description is used to generate tags and improve search results.
-  #   * Think: What does it do? Why did you write it? What is the focus?
-  #   * Try to keep it short, snappy and to the point.
-  #   * Write the description between the DESC delimiters below.
-  #   * Finally, don't worry about the indent, CocoaPods strips it!
   s.description  = <<-DESC
-Efficiently generate secure, randmo strings of specified entropy from various character sets for use when probabilisticly unique string identifiers are needed. Entropy is specified by total number of strings and acceptable risk of a repeat.
+Efficiently generate cryptographically strong and secure random strings of specified entropy from various character sets for use when probabilisticly unique string identifiers are needed. Entropy is calculated from a total number of strings and acceptable risk of a repeat.
                    DESC
 
   s.homepage = "https://github.com/#{s.name}/#{s.name}-Swift"
   s.license  = { :type => "MIT", :file => "LICENSE" }
   s.authors   = { "knoxen" => "paul@knoxen.com", "dingo sky" => "paul@dingosky.com" }
-  # s.authors            = { "dingo sky" => "paul@dingosky.com" }
   # s.social_media_url   = "http://twitter.com/knoxen"
 
   # ――― Platform Specifics ――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
@@ -35,18 +29,9 @@ Efficiently generate secure, randmo strings of specified entropy from various ch
   # s.watchos.deployment_target = "2.0"
   # s.tvos.deployment_target = "9.0"
 
-
-  # ――― Source Location ―――――――――――――――――――――――――――――――――――――――――――――――――――――――――― #
-  #
-  #  Specify the location from where the source should be retrieved.
-  #  Supports git, hg, bzr, svn and HTTP.
-  #
-
   s.source = { :git => "https://github.com/EntropyString/EntropyString-Swift.git", :tag => "#{s.version}" }
 
   s.source_files  = "Sources/**/*.swift"
 #   s.public_header_files = "#{s.name}/{s.name}.h"
 
-  # s.dependency "JSONKit", "~> 1.4"
-
 end
diff --git a/Sources/RandomString.swift b/Sources/RandomString.swift
@@ -201,7 +201,7 @@ public class RandomString {
         string.append(char(ndx, from: chars))
       }
     }
-    for slice in 0..<partials {
+    for slice in 0 ..< partials {
       let ndx = ndxFn(bytes, Int(chunks), Int(slice))
       string.append(char(ndx, from: chars))
     }
@@ -304,7 +304,7 @@ public class RandomString {
   ///
   /// - return: The index into the `charSet64` characters.
   private func ndx64(_ bytes: Bytes, _ chunk: Int, _ slice: Int) -> UInt8 {
-    guard slice < 4 else { fatalError("Invalid slice for charSet64 chars") }
+    guard slice < CharSet.charSet64.charsPerChunk else { fatalError("Invalid slice for charSet64 chars") }
     return ndxGen(bytes, chunk, slice, 6)
   }
 
@@ -320,7 +320,7 @@ public class RandomString {
   ///
   /// - return: The index into the `charSet32` characters.
   private func ndx32(_ bytes: Bytes, _ chunk: Int, _ slice: Int) -> UInt8 {
-    guard slice < 8 else { fatalError("Invalid slice for charSet32 chars") }
+    guard slice < CharSet.charSet32.charsPerChunk else { fatalError("Invalid slice for charSet32 chars") }
     return ndxGen(bytes, chunk, slice, 5)
   }
   
@@ -336,7 +336,7 @@ public class RandomString {
   ///
   /// - return: The index into the `charSet16` characters.
   private func ndx16(_ bytes: Bytes, _ chunk: Int, _ slice: Int) -> UInt8 {
-    guard slice < 2 else { fatalError("Invalid slice for charSet16 chars") }
+    guard slice < CharSet.charSet16.charsPerChunk else { fatalError("Invalid slice for charSet16 chars") }
     return (bytes[chunk]<<UInt8(4*slice))>>4
   }
   
@@ -352,7 +352,7 @@ public class RandomString {
   ///
   /// - return: The index into the `charSet8` characters.
   private func ndx8(_ bytes: Bytes, _ chunk: Int, _ slice: Int) -> UInt8 {
-    guard slice < 8 else { fatalError("Invalid slice for charSet8 chars") }
+    guard slice < CharSet.charSet8.charsPerChunk else { fatalError("Invalid slice for charSet8 chars") }
     return ndxGen(bytes, chunk, slice, 3)
   }
   
@@ -368,7 +368,7 @@ public class RandomString {
   ///
   /// - return: The index into the `charSet4` characters.
   private func ndx4(_ bytes: Bytes, _ chunk: Int, _ slice: Int) -> UInt8 {
-    guard slice < 4 else { fatalError("Invalid slice for charSet4 chars") }
+    guard slice < CharSet.charSet4.charsPerChunk else { fatalError("Invalid slice for charSet4 chars") }
     return (bytes[chunk]<<UInt8(2*slice))>>6
   }
   
@@ -384,10 +384,21 @@ public class RandomString {
   ///
   /// - return: The index into the `charSet2` characters.
   private func ndx2(_ bytes: Bytes, _ chunk: Int, _ slice: Int) -> UInt8 {
-    guard slice < 8 else { fatalError("Invalid slice for charSet2 chars") }
+    guard slice < CharSet.charSet2.charsPerChunk else { fatalError("Invalid slice for charSet2 chars") }
     return (bytes[chunk]<<UInt8(slice))>>7
   }
 
+  /// Determines index into general CharSet characters.
+  ///
+  /// Each `slice` of bits is used to create a single character. A `chunk` is the number of
+  /// __Bytes__ required for a exact multiple of `slice`s. This function indexes into the _chunk_
+  /// chunk of __Bytes__ to get the _slice_ of bits for generating a character.
+  ///
+  /// - parameter bytes: The __Bytes__ used for character generation
+  /// - parameter chunk: The _chunk_ into the __Bytes__.
+  /// - parameter slice: The _slice_ of the _chunk_.
+  ///
+  /// - return: The index into the `charSet2` characters.
   private func ndxGen(_ bytes: Bytes, _ chunk: Int, _ slice: Int, _ bitsPerSlice: Int) -> UInt8 {
     var ndx: UInt8 = 0
     
