Fix Style/UnpackFirst cop.

.rubocop_todo.yml

@@ -335,15 +335,6 @@ Style/TrailingCommaInHashLiteral:
   Exclude:
     - 'lib/zip/constants.rb'
 
-# Offense count: 6
-# Cop supports --auto-correct.
-Style/UnpackFirst:
-  Exclude:
-    - 'lib/zip/entry.rb'
-    - 'lib/zip/extra_field.rb'
-    - 'lib/zip/extra_field/generic.rb'
-    - 'lib/zip/extra_field/zip64.rb'
-
 # Offense count: 247
 # Cop supports --auto-correct.
 # Configuration parameters: AutoCorrect, AllowHeredoc, AllowURI, URISchemes, IgnoreCopDirectives, IgnoredPatterns.

lib/zip/entry.rb

@@ -194,15 +194,15 @@ module Zip
 
     class << self
       def read_zip_short(io) # :nodoc:
-        io.read(2).unpack('v')[0]
+        io.read(2).unpack1('v')
       end
 
       def read_zip_long(io) # :nodoc:
-        io.read(4).unpack('V')[0]
+        io.read(4).unpack1('V')
       end
 
       def read_zip_64_long(io) # :nodoc:
-        io.read(8).unpack('Q<')[0]
+        io.read(8).unpack1('Q<')
       end
 
       def read_c_dir_entry(io) #:nodoc:all

lib/zip/extra_field.rb

@@ -40,7 +40,7 @@ module Zip
       i = 0
       while i < binstr.bytesize
         id  = binstr[i, 2]
-        len = binstr[i + 2, 2].to_s.unpack('v').first
+        len = binstr[i + 2, 2].to_s.unpack1('v')
         if id && ID_MAP.member?(id)
           extra_field_type_exist(binstr, id, len, i)
         elsif id

lib/zip/extra_field/generic.rb

@@ -19,7 +19,7 @@ module Zip
         return false
       end
 
-      [binstr[2, 2].unpack('v')[0], binstr[4..-1]]
+      [binstr[2, 2].unpack1('v'), binstr[4..-1]]
     end
 
     def ==(other)

lib/zip/extra_field/zip64.rb

@@ -46,7 +46,7 @@ module Zip
     end
 
     def extract(size, format)
-      @content.slice!(0, size).unpack(format)[0]
+      @content.slice!(0, size).unpack1(format)
     end
     private :extract