huffman.rb in http-2-0.12.0

- old
+ new

@@ -1,5 +1,7 @@
+# frozen_string_literal: true
+
 require_relative 'error'
 
 module HTTP2
   # Implementation of huffman encoding for HPACK
   #
@@ -18,42 +20,42 @@
       #
       # @param str [String]
       # @return [String] binary string
       def encode(str)
         bitstring = str.each_byte.map { |chr| ENCODE_TABLE[chr] }.join
-        bitstring << '1' * ((8 - bitstring.size) % 8)
+        bitstring << ('1' * ((8 - bitstring.size) % 8))
         [bitstring].pack('B*')
       end
 
       # Decodes provided Huffman coded string.
       #
       # @param buf [Buffer]
       # @return [String] binary string
       # @raise [CompressionError] when Huffman coded string is malformed
       def decode(buf)
-        emit = ''
+        emit = String.new
         state = 0 # start state
 
         mask = (1 << BITS_AT_ONCE) - 1
         buf.each_byte do |chr|
-          (8 / BITS_AT_ONCE - 1).downto(0) do |shift|
+          ((8 / BITS_AT_ONCE) - 1).downto(0) do |shift|
             branch = (chr >> (shift * BITS_AT_ONCE)) & mask
             # MACHINE[state] = [final, [transitions]]
             #  [final] unfinished bits so far are prefix of the EOS code.
             # Each transition is [emit, next]
             #  [emit] character to be emitted on this transition, empty string, or EOS.
             #  [next] next state number.
             trans = MACHINE[state][branch]
-            fail CompressionError, 'Huffman decode error (EOS found)' if trans.first == EOS
+            raise CompressionError, 'Huffman decode error (EOS found)' if trans.first == EOS
+
             emit << trans.first.chr if trans.first
             state = trans.last
           end
         end
         # Check whether partial input is correctly filled
-        unless state <= MAX_FINAL_STATE
-          fail CompressionError, 'Huffman decode error (EOS invalid)'
-        end
+        raise CompressionError, 'Huffman decode error (EOS invalid)' unless state <= MAX_FINAL_STATE
+
         emit.force_encoding(Encoding::BINARY)
       end
 
       # Huffman table as specified in
       # - http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-10#appendix-B
@@ -151,27 +153,27 @@
         [0xfd,  8],
         [0x1ffb, 13],
         [0x7fff0, 19],
         [0x1ffc, 13],
         [0x3ffc, 14],
-        [0x22,  6],
+        [0x22, 6],
         [0x7ffd, 15],
-        [0x3,  5],
-        [0x23,  6],
-        [0x4,  5],
-        [0x24,  6],
-        [0x5,  5],
+        [0x3, 5],
+        [0x23, 6],
+        [0x4, 5],
+        [0x24, 6],
+        [0x5, 5],
         [0x25,  6],
         [0x26,  6],
         [0x27,  6],
-        [0x6,  5],
+        [0x6, 5],
         [0x74,  7],
         [0x75,  7],
         [0x28,  6],
         [0x29,  6],
         [0x2a,  6],
-        [0x7,  5],
+        [0x7, 5],
         [0x2b,  6],
         [0x76,  7],
         [0x2c,  6],
         [0x8,  5],
         [0x9,  5],
@@ -312,12 +314,12 @@
         [0x7ffffed, 27],
         [0x7ffffee, 27],
         [0x7ffffef, 27],
         [0x7fffff0, 27],
         [0x3ffffee, 26],
-        [0x3fffffff, 30],
+        [0x3fffffff, 30]
       ].each(&:freeze).freeze
 
-      ENCODE_TABLE = CODES.map { |c, l| [c].pack('N').unpack('B*').first[-l..-1] }.each(&:freeze).freeze
+      ENCODE_TABLE = CODES.map { |c, l| [c].pack('N').unpack1('B*')[-l..-1] }.each(&:freeze).freeze
     end
   end
 end