[ruby/securerandom] [DOC] Add documents of methods and constants

https://github.com/ruby/securerandom/commit/9a99978135

lib/random/formatter.rb

@@ -292,6 +292,7 @@ module Random::Formatter
     end
   end
 
+  # Internal interface to Random; Generate random data _n_ bytes.
   private def gen_random(n)
     self.bytes(n)
   end
@@ -339,7 +340,9 @@ module Random::Formatter
     result
   end
 
+  # The default character list for #alphanumeric.
   ALPHANUMERIC = [*'A'..'Z', *'a'..'z', *'0'..'9']
+
   # Generate a random alphanumeric string.
   #
   # The argument _n_ specifies the length, in characters, of the alphanumeric

lib/securerandom.rb

@@ -40,19 +40,25 @@ require 'random/formatter'
 
 module SecureRandom
 
+  # The version
   VERSION = "0.3.0"
 
   class << self
+    # Returns a random binary string containing +size+ bytes.
+    #
+    # See Random.bytes
     def bytes(n)
       return gen_random(n)
     end
 
     private
 
+    # Implementation using OpenSSL
     def gen_random_openssl(n)
       return OpenSSL::Random.random_bytes(n)
     end
 
+    # Implementation using system random device
     def gen_random_urandom(n)
       ret = Random.urandom(n)
       unless ret
@@ -78,6 +84,7 @@ module SecureRandom
       end
     end
 
+    # Generate random data bytes for Random::Formatter
     public :gen_random
   end
 end