lib/dionysus/digest.rb in dionysus-0.3.0 vs lib/dionysus/digest.rb in dionysus-0.3.1

@@ -63,39 +63,69 @@
   end
   
   ##
   # The lengths of the registered digests in the given encoding.
   def self.digest_lengths( encoding = :binary )
-    if encoding.is_a?(Symbol)
-      bits_per_char = case encoding
-        when :binary then 8
-        when :base64 then 6
-        when :hex, :hexidecimal then 4
-        when :bit then 1
-        else raise ArgumentError, "Invalid encoding"
-      end
+    if encoding == :bit or encoding == 1
+      _digest_lengths(1)
+    elsif encoding.is_a?(Symbol) and String::ENCODING_BITS_PER_CHAR[encoding]
+      _digest_lengths(String::ENCODING_BITS_PER_CHAR[encoding])
     elsif encoding.is_a?(Integer) and encoding > 0
-      bits_per_char = encoding
+      _digest_lengths(encoding)
     else
       raise ArgumentError, "Invalid encoding"
     end
-    
-    Hash[ self.digests.collect { |dig, info| [dig, info[:bit_length] / bits_per_char] } ]
   end
   
   ##
   # Calculate the given digest of the given string.
   #
   # Examples:
   #
   #     Digest.digest(:sha512, 'foobar') #=> binary digest
   #     Digest.digest(Digest::SHA512, 'foobar') #=> binary digest
-  def self.digest( sym_or_klass, str )
-    if sym_or_klass.is_a?(Class)
-      sym_or_klass
-    else
-      Digest.const_get(sym_or_klass.to_s.upcase)
-    end.digest(str)
+  def self.digest( sym, str )
+    Digest.const_get(sym.to_s.upcase).digest(str)
+  end
+  
+  ##
+  # Detect the digest of the string.  Returns nil if the digest cannot be 
+  # determined.
+  #
+  # Example:
+  #     Digest.detect_digest("wxeCFXPVXePFcpwuFDjonyn1G/w=", :base64) #=> :sha1
+  #     Digest.detect_digest("foobar", :hex) #=> nil
+  def self.detect_digest( string, encoding = :binary )
+    string = string.strip unless encoding == :binary
+    dig = self.digest_lengths(encoding).invert[string.length]
+    dig = :sha256 if dig == :sha2
+    dig
+  end
+  
+  ##
+  # Detect the digest of the string.  Returns nil if the digest cannot be 
+  # determined.
+  #
+  # Example:
+  #     Digest.detect_digest!("wxeCFXPVXePFcpwuFDjonyn1G/w=", :base64) #=> :sha1
+  #     Digest.detect_digest!("foobar", :hex) #=> RuntimeError
+  def self.detect_digest!( string, encoding = :binary )
+    self.detect_digest(string, encoding) or raise("Unknown digest")
+  end
+  
+  private
+  
+  def self._digest_lengths( bits_per_char ) # :nodoc:
+    padding_factor = (bits_per_char.lcm(8) / bits_per_char)
+    
+    returning result={} do
+      self.digests.each do |dig, info|
+        result[dig] = len = info[:bit_length] / bits_per_char
+        if (t_ = len % padding_factor) != 0
+          result[dig] = len + (padding_factor - t_)
+        end
+      end
+    end
   end
 end
 
 # Register some default digests
 Digest::DEFAULT_DIGESTS.each do |dig|