From feed5c13ffa466acd2ebbce9b050b39e5a3e654e Mon Sep 17 00:00:00 2001
From: meh <meh@schizofreni.co>
Date: Tue, 14 May 2013 01:39:15 +0200
Subject: [PATCH 1/2] Fix String.valid_codepoint? tests

---
 lib/elixir/lib/string.ex               | 2 +-
 lib/elixir/test/elixir/string_test.exs | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/elixir/lib/string.ex b/lib/elixir/lib/string.ex
index 14644bf2974..41693b658bc 100644
--- a/lib/elixir/lib/string.ex
+++ b/lib/elixir/lib/string.ex
@@ -470,7 +470,7 @@ defmodule String do
       true
       iex> String.valid_codepoint?("ø")
       true
-      iex> String.valid_codepoint?("\xffff")
+      iex> String.valid_codepoint?(<<0xffff :: 16>>)
       false
       iex> String.valid_codepoint?("asdf")
       false
diff --git a/lib/elixir/test/elixir/string_test.exs b/lib/elixir/test/elixir/string_test.exs
index 51d6e58491b..9196a54a175 100644
--- a/lib/elixir/test/elixir/string_test.exs
+++ b/lib/elixir/test/elixir/string_test.exs
@@ -233,7 +233,7 @@ defmodule StringTest do
     assert String.valid_codepoint?("ø")
     assert String.valid_codepoint?("あ")
 
-    refute String.valid_codepoint?("\xffff")
+    refute String.valid_codepoint?(<<0xffff :: 16>>)
     refute String.valid_codepoint?("ab")
   end
 

From 1d6fd3c4c8a07dd1de00e97c954f0d8ebcf18a67 Mon Sep 17 00:00:00 2001
From: meh <meh@schizofreni.co>
Date: Tue, 14 May 2013 01:39:30 +0200
Subject: [PATCH 2/2] Add String.valid?

---
 lib/elixir/lib/string.ex               | 28 ++++++++++++++++++++++++++
 lib/elixir/test/elixir/string_test.exs |  9 +++++++++
 2 files changed, 37 insertions(+)

diff --git a/lib/elixir/lib/string.ex b/lib/elixir/lib/string.ex
index 41693b658bc..546f06e9473 100644
--- a/lib/elixir/lib/string.ex
+++ b/lib/elixir/lib/string.ex
@@ -458,6 +458,34 @@ defmodule String do
   @spec next_codepoint(t) :: {codepoint, t} | :no_codepoint
   defdelegate next_codepoint(string), to: String.Unicode
 
+  @doc %B"""
+  Checks whether `str` is a valid UTF-8 string.
+
+  ## Examples
+
+      iex> String.valid?("a")
+      true
+      iex> String.valid?("ø")
+      true
+      iex> String.valid?(<<0xffff :: 16>>)
+      false
+      iex> String.valid?("asd" <> <<0xffff :: 16>>)
+      false
+
+  """
+  @spec valid?(t) :: boolean
+  def valid?(<<_ :: utf8, t :: binary>>) do
+    valid?(t)
+  end
+
+  def valid?(<<>>) do
+    true
+  end
+
+  def valid?(_) do
+    false
+  end
+
   @doc %B"""
   Checks whether `str` is a valid codepoint.
 
diff --git a/lib/elixir/test/elixir/string_test.exs b/lib/elixir/test/elixir/string_test.exs
index 9196a54a175..b226cc18847 100644
--- a/lib/elixir/test/elixir/string_test.exs
+++ b/lib/elixir/test/elixir/string_test.exs
@@ -228,6 +228,15 @@ defmodule StringTest do
     assert String.slice("", 0, 1) == nil
   end
 
+  test :valid? do
+    assert String.valid?("afds")
+    assert String.valid?("øsdfh")
+    assert String.valid?("dskfjあska")
+
+    refute String.valid?(<<0xffff :: 16>>)
+    refute String.valid?("asd" <> <<0xffff :: 16>>)
+  end
+
   test :valid_codepoint? do
     assert String.valid_codepoint?("a")
     assert String.valid_codepoint?("ø")