Replace stringy crap with real bitwise arithmetic

Besides it being retarded to use strings for this stuff, it was broken on JRuby

lib/cryptosphere/git/pack_object.rb

@@ -16,22 +16,23 @@ class PackObject
       # @param [String] buffer to be processed
       # @return [PackObject, nil] PackObject or nil if more data is needed
       def self.parse_header(buffer)
-        byte     = buffer[0].unpack("B8").first
+        byte     = buffer[0].ord
         consumed = 1
 
-        more   = byte[0,1]
-        type   = Integer(byte[1,3], 2)
-        length = Integer(byte[4,4], 2)
+        more   = byte >> 7 & 0x1
+        type   = byte >> 4 & 0x7
+        length = byte & 0xf
 
-        while more == "1"
+        while more == 1
           raise FormatError, "object header too long" if consumed >= HEADER_SANITY_LIMIT
 
           # Need more data
           return nil if consumed >= buffer.length
 
-          byte = buffer[consumed].unpack("B8").first
-          more = byte[0,1]
-          length   += Integer(byte[1,7], 2)
+          byte   = buffer[consumed].ord
+          more   = byte >> 7 & 0x1
+          length += byte & 0x7f
+
           consumed += 1
         end
 

spec/cryptosphere/git/pack_reader_spec.rb

@@ -3,7 +3,8 @@
 require 'stringio'
 
 describe Cryptosphere::Git::PackReader do
-  subject { described_class.new(StringIO.new(fixture('packfile'))) }
+  let(:stringio) { StringIO.new(fixture('packfile')).set_encoding("ASCII-8BIT") }
+  subject { described_class.new(stringio) }
 
   it "returns the next object in the pack" do
     obj = subject.next_object