Move string files in base/ to the string subdirectory.

BUG=247723
TEST=no change

Review URL: https://chromiumcodereview.appspot.com/16331011

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@205050 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/base/strings/string16.cc b/base/strings/string16.cc
new file mode 100644
index 0000000..c802eef
--- /dev/null
+++ b/base/strings/string16.cc
@@ -0,0 +1,82 @@
+// 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.
+
+#include "base/strings/string16.h"
+
+#if defined(WCHAR_T_IS_UTF16)
+
+#error This file should not be used on 2-byte wchar_t systems
+// If this winds up being needed on 2-byte wchar_t systems, either the
+// definitions below can be used, or the host system's wide character
+// functions like wmemcmp can be wrapped.
+
+#elif defined(WCHAR_T_IS_UTF32)
+
+#include <ostream>
+
+#include "base/strings/utf_string_conversions.h"
+
+namespace base {
+
+int c16memcmp(const char16* s1, const char16* s2, size_t n) {
+  // We cannot call memcmp because that changes the semantics.
+  while (n-- > 0) {
+    if (*s1 != *s2) {
+      // We cannot use (*s1 - *s2) because char16 is unsigned.
+      return ((*s1 < *s2) ? -1 : 1);
+    }
+    ++s1;
+    ++s2;
+  }
+  return 0;
+}
+
+size_t c16len(const char16* s) {
+  const char16 *s_orig = s;
+  while (*s) {
+    ++s;
+  }
+  return s - s_orig;
+}
+
+const char16* c16memchr(const char16* s, char16 c, size_t n) {
+  while (n-- > 0) {
+    if (*s == c) {
+      return s;
+    }
+    ++s;
+  }
+  return 0;
+}
+
+char16* c16memmove(char16* s1, const char16* s2, size_t n) {
+  return static_cast<char16*>(memmove(s1, s2, n * sizeof(char16)));
+}
+
+char16* c16memcpy(char16* s1, const char16* s2, size_t n) {
+  return static_cast<char16*>(memcpy(s1, s2, n * sizeof(char16)));
+}
+
+char16* c16memset(char16* s, char16 c, size_t n) {
+  char16 *s_orig = s;
+  while (n-- > 0) {
+    *s = c;
+    ++s;
+  }
+  return s_orig;
+}
+
+std::ostream& operator<<(std::ostream& out, const string16& str) {
+  return out << UTF16ToUTF8(str);
+}
+
+void PrintTo(const string16& str, std::ostream* out) {
+  *out << str;
+}
+
+}  // namespace base
+
+template class std::basic_string<char16, base::string16_char_traits>;
+
+#endif  // WCHAR_T_IS_UTF32