backporting IO#binread for 1.8 users

activesupport/lib/active_support/core_ext/io.rb

@@ -0,0 +1,15 @@
+if RUBY_VERSION < '1.9.2'
+
+# :stopdoc:
+class IO
+  def self.binread(name, length = nil, offset = nil)
+    return File.read name unless length || offset
+    File.open(name, 'rb') { |f|
+      f.seek offset if offset
+      f.read length
+    }
+  end
+end
+# :startdoc:
+
+end

activesupport/test/core_ext/io_test.rb

@@ -0,0 +1,23 @@
+require 'abstract_unit'
+
+require 'active_support/core_ext/io'
+
+class IOTest < Test::Unit::TestCase
+  def test_binread_one_arg
+    assert_equal File.read(__FILE__), IO.binread(__FILE__)
+  end
+
+  def test_binread_two_args
+    assert_equal File.read(__FILE__).bytes.first(10).pack('C*'),
+      IO.binread(__FILE__, 10)
+  end
+
+  def test_binread_three_args
+    actual = IO.binread(__FILE__, 5, 10)
+    expected = File.open(__FILE__, 'rb') { |f|
+      f.seek 10
+      f.read 5
+    }
+    assert_equal expected, actual
+  end
+end