1 files changed, 229 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/strings/string16.h b/security/sandbox/chromium/base/strings/string16.h
new file mode 100644
index 0000000000..3cb6c7c495
--- /dev/null
+++ b/security/sandbox/chromium/base/strings/string16.h
@@ -0,0 +1,229 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BASE_STRINGS_STRING16_H_
+#define BASE_STRINGS_STRING16_H_
+
+// WHAT:
+// A version of std::basic_string that provides 2-byte characters even when
+// wchar_t is not implemented as a 2-byte type. You can access this class as
+// string16. We also define char16, which string16 is based upon.
+//
+// WHY:
+// On Windows, wchar_t is 2 bytes, and it can conveniently handle UTF-16/UCS-2
+// data. Plenty of existing code operates on strings encoded as UTF-16.
+//
+// On many other platforms, sizeof(wchar_t) is 4 bytes by default. We can make
+// it 2 bytes by using the GCC flag -fshort-wchar. But then std::wstring fails
+// at run time, because it calls some functions (like wcslen) that come from
+// the system's native C library -- which was built with a 4-byte wchar_t!
+// It's wasteful to use 4-byte wchar_t strings to carry UTF-16 data, and it's
+// entirely improper on those systems where the encoding of wchar_t is defined
+// as UTF-32.
+//
+// Here, we define string16, which is similar to std::wstring but replaces all
+// libc functions with custom, 2-byte-char compatible routines. It is capable
+// of carrying UTF-16-encoded data.
+
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+
+#include <functional>
+#include <string>
+
+#include "base/base_export.h"
+#include "build/build_config.h"
+
+#if defined(WCHAR_T_IS_UTF16)
+
+// Define a macro for wrapping construction of char16 arrays and string16s from
+// a literal string. This indirection allows for an easier migration of
+// base::char16 to char16_t on platforms where WCHAR_T_IS_UTF16, as only a one
+// character change to the macro will be necessary.
+// This macro does not exist when WCHAR_T_IS_UTF32, as it is currently not
+// possible to create a char array form a literal in this case.
+// TODO(https://crbug.com/911896): Remove this macro once base::char16 is
+// char16_t on all platforms.
+#define STRING16_LITERAL(x) L##x
+
+namespace base {
+
+typedef wchar_t char16;
+typedef std::wstring string16;
+
+}  // namespace base
+
+#elif defined(WCHAR_T_IS_UTF32)
+
+#include <wchar.h>  // for mbstate_t
+
+namespace base {
+
+typedef uint16_t char16;
+
+// char16 versions of the functions required by string16_char_traits; these
+// are based on the wide character functions of similar names ("w" or "wcs"
+// instead of "c16").
+BASE_EXPORT int c16memcmp(const char16* s1, const char16* s2, size_t n);
+BASE_EXPORT size_t c16len(const char16* s);
+BASE_EXPORT const char16* c16memchr(const char16* s, char16 c, size_t n);
+BASE_EXPORT char16* c16memmove(char16* s1, const char16* s2, size_t n);
+BASE_EXPORT char16* c16memcpy(char16* s1, const char16* s2, size_t n);
+BASE_EXPORT char16* c16memset(char16* s, char16 c, size_t n);
+
+// This namespace contains the implementation of base::string16 along with
+// things that need to be found via argument-dependent lookup from a
+// base::string16.
+namespace string16_internals {
+
+struct string16_char_traits {
+  typedef char16 char_type;
+  typedef int int_type;
+
+  // int_type needs to be able to hold each possible value of char_type, and in
+  // addition, the distinct value of eof().
+  static_assert(sizeof(int_type) > sizeof(char_type),
+                "int must be larger than 16 bits wide");
+
+  typedef std::streamoff off_type;
+  typedef mbstate_t state_type;
+  typedef std::fpos<state_type> pos_type;
+
+  static void assign(char_type& c1, const char_type& c2) {
+    c1 = c2;
+  }
+
+  static bool eq(const char_type& c1, const char_type& c2) {
+    return c1 == c2;
+  }
+  static bool lt(const char_type& c1, const char_type& c2) {
+    return c1 < c2;
+  }
+
+  static int compare(const char_type* s1, const char_type* s2, size_t n) {
+    return c16memcmp(s1, s2, n);
+  }
+
+  static size_t length(const char_type* s) {
+    return c16len(s);
+  }
+
+  static const char_type* find(const char_type* s, size_t n,
+                               const char_type& a) {
+    return c16memchr(s, a, n);
+  }
+
+  static char_type* move(char_type* s1, const char_type* s2, size_t n) {
+    return c16memmove(s1, s2, n);
+  }
+
+  static char_type* copy(char_type* s1, const char_type* s2, size_t n) {
+    return c16memcpy(s1, s2, n);
+  }
+
+  static char_type* assign(char_type* s, size_t n, char_type a) {
+    return c16memset(s, a, n);
+  }
+
+  static int_type not_eof(const int_type& c) {
+    return eq_int_type(c, eof()) ? 0 : c;
+  }
+
+  static char_type to_char_type(const int_type& c) {
+    return char_type(c);
+  }
+
+  static int_type to_int_type(const char_type& c) {
+    return int_type(c);
+  }
+
+  static bool eq_int_type(const int_type& c1, const int_type& c2) {
+    return c1 == c2;
+  }
+
+  static int_type eof() {
+    return static_cast<int_type>(EOF);
+  }
+};
+
+}  // namespace string16_internals
+
+typedef std::basic_string<char16,
+                          base::string16_internals::string16_char_traits>
+    string16;
+
+namespace string16_internals {
+
+BASE_EXPORT extern std::ostream& operator<<(std::ostream& out,
+                                            const string16& str);
+
+// This is required by googletest to print a readable output on test failures.
+BASE_EXPORT extern void PrintTo(const string16& str, std::ostream* out);
+
+}  // namespace string16_internals
+
+}  // namespace base
+
+// The string class will be explicitly instantiated only once, in string16.cc.
+//
+// std::basic_string<> in GNU libstdc++ contains a static data member,
+// _S_empty_rep_storage, to represent empty strings.  When an operation such
+// as assignment or destruction is performed on a string, causing its existing
+// data member to be invalidated, it must not be freed if this static data
+// member is being used.  Otherwise, it counts as an attempt to free static
+// (and not allocated) data, which is a memory error.
+//
+// Generally, due to C++ template magic, _S_empty_rep_storage will be marked
+// as a coalesced symbol, meaning that the linker will combine multiple
+// instances into a single one when generating output.
+//
+// If a string class is used by multiple shared libraries, a problem occurs.
+// Each library will get its own copy of _S_empty_rep_storage.  When strings
+// are passed across a library boundary for alteration or destruction, memory
+// errors will result.  GNU libstdc++ contains a configuration option,
+// --enable-fully-dynamic-string (_GLIBCXX_FULLY_DYNAMIC_STRING), which
+// disables the static data member optimization, but it's a good optimization
+// and non-STL code is generally at the mercy of the system's STL
+// configuration.  Fully-dynamic strings are not the default for GNU libstdc++
+// libstdc++ itself or for the libstdc++ installations on the systems we care
+// about, such as Mac OS X and relevant flavors of Linux.
+//
+// See also http://gcc.gnu.org/bugzilla/show_bug.cgi?id=24196 .
+//
+// To avoid problems, string classes need to be explicitly instantiated only
+// once, in exactly one library.  All other string users see it via an "extern"
+// declaration.  This is precisely how GNU libstdc++ handles
+// std::basic_string<char> (string) and std::basic_string<wchar_t> (wstring).
+//
+// This also works around a Mac OS X linker bug in ld64-85.2.1 (Xcode 3.1.2),
+// in which the linker does not fully coalesce symbols when dead code
+// stripping is enabled.  This bug causes the memory errors described above
+// to occur even when a std::basic_string<> does not cross shared library
+// boundaries, such as in statically-linked executables.
+//
+// TODO(mark): File this bug with Apple and update this note with a bug number.
+
+extern template class BASE_EXPORT
+    std::basic_string<base::char16,
+                      base::string16_internals::string16_char_traits>;
+
+// Specialize std::hash for base::string16. Although the style guide forbids
+// this in general, it is necessary for consistency with WCHAR_T_IS_UTF16
+// platforms, where base::string16 is a type alias for std::wstring.
+namespace std {
+template <>
+struct hash<base::string16> {
+  std::size_t operator()(const base::string16& s) const {
+    std::size_t result = 0;
+    for (base::char16 c : s)
+      result = (result * 131) + c;
+    return result;
+  }
+};
+}  // namespace std
+
+#endif  // WCHAR_T_IS_UTF32
+
+#endif  // BASE_STRINGS_STRING16_H_