Remove C++11 features in io_win32.cc

- Use scoped_array instead of unique_ptr.
- Do not use string::front() and string::back()

src/google/protobuf/stubs/io_win32.cc

@@ -57,6 +57,7 @@
 #include <windows.h>
 
 #include <google/protobuf/stubs/io_win32.h>
+#include <google/protobuf/stubs/scoped_ptr.h>
 
 #include <cassert>
 #include <memory>
@@ -71,7 +72,6 @@ namespace win32 {
 namespace {
 
 using std::string;
-using std::unique_ptr;
 using std::wstring;
 
 template <typename char_type>
@@ -139,11 +139,11 @@ string join_paths(const string& path1, const string& path2) {
     return path1;
   }
 
-  if (is_separator(path1.back())) {
-    return is_separator(path2.front()) ? (path1 + path2.substr(1))
+  if (is_separator(path1[path1.size() - 1])) {
+    return is_separator(path2[0]) ? (path1 + path2.substr(1))
                                        : (path1 + path2);
   } else {
-    return is_separator(path2.front()) ? (path1 + path2)
+    return is_separator(path2[0]) ? (path1 + path2)
                                        : (path1 + '\\' + path2);
   }
 }
@@ -203,24 +203,24 @@ string normalize(string path) {
     result << s;
   }
   // Preserve trailing separator if the input contained it.
-  if (is_separator(path.back())) {
+  if (!path.empty() && is_separator(path[path.size() - 1])) {
     result << '\\';
   }
   return result.str();
 }
 
-std::unique_ptr<WCHAR[]> as_wstring(const string& s) {
+WCHAR* as_wstring(const string& s) {
   int len = ::MultiByteToWideChar(CP_UTF8, 0, s.c_str(), s.size(), NULL, 0);
-  std::unique_ptr<WCHAR[]> result(new WCHAR[len + 1]);
+  WCHAR* result = new WCHAR[len + 1];
   ::MultiByteToWideChar(CP_UTF8, 0, s.c_str(), s.size(), result.get(), len + 1);
-  result.get()[len] = 0;
-  return std::move(result);
+  result[len] = 0;
+  return result;
 }
 
-wstring as_wchar_path(const string& path) {
-  std::unique_ptr<WCHAR[]> wbuf(as_wstring(path));
-  replace_directory_separators(wbuf.get());
-  return wstring(wbuf.get());
+void as_wchar_path(const string& path, wstring* wchar_path) {
+  scoped_array<WCHAR> wbuf(as_wstring(path));
+  replace_directory_separators(wbuf);
+  wchar_path->assign(wbuf);
 }
 
 bool as_windows_path(const string& path, wstring* result) {
@@ -239,7 +239,7 @@ bool as_windows_path(const string& path, wstring* result) {
     ::GetCurrentDirectoryA(MAX_PATH, cwd);
     mutable_path = join_paths(cwd, mutable_path);
   }
-  *result = as_wchar_path(normalize(mutable_path));
+  as_wchar_path(normalize(mutable_path), result);
   if (!has_longpath_prefix(result->c_str())) {
     // Add the "\\?\" prefix unconditionally. This way we prevent the Win32 API
     // from processing the path and "helpfully" removing trailing dots from the
@@ -324,7 +324,7 @@ FILE* fopen(const char* path, const char* mode) {
     errno = ENOENT;
     return NULL;
   }
-  std::unique_ptr<WCHAR[]> wmode(as_wstring(mode));
+  scoped_array<WCHAR> wmode(as_wstring(mode));
   return ::_wfopen(wpath.c_str(), wmode.get());
 #else
   return ::fopen(path, mode);