Clean up and fix Utils::ToUTF8String() and Utils::ToUTF16String()

src/Utils.cpp

 /*
  * This file is part of Adblock Plus <http://adblockplus.org/>,
  * Copyright (C) 2006-2013 Eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with Adblock Plus.  If not, see <http://www.gnu.org/licenses/>.
  */
 
 #include <sstream>
 #include <string>
 
 #include "Utils.h"
 #ifdef _WIN32
 #include <Windows.h>
 #include <Shlwapi.h>
 
 #include <algorithm>
 #include <cctype>
 #include <functional>
+#include <stdexcept>
 
 #endif
 
 using namespace AdblockPlus;
 
 std::string Utils::Slurp(std::ios& stream)
 {
   std::stringstream content;
   content << stream.rdbuf();
   return content.str();
 }
 
 std::string Utils::FromV8String(v8::Handle<v8::Value> value)
 {
   v8::String::Utf8Value stringValue(value);
   if (stringValue.length())
     return std::string(*stringValue, stringValue.length());
   else
     return std::string();
 }
 
 v8::Local<v8::String> Utils::ToV8String(const std::string& str)
 {
   return v8::String::New(str.c_str(), str.length());
 }
 
 #ifdef _WIN32
-std::wstring Utils::ToUTF16String(const std::string& str, unsigned long length)
+std::wstring Utils::ToUTF16String(const std::string& str)
 {
+  size_t length = str.size();
   if (length == 0)
     return std::wstring();
-  DWORD utf16StringLength = 0;
-  std::wstring utf16String;
-  utf16StringLength = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), length, &utf16String[0], utf16StringLength);
-  if (utf16StringLength > 0)
-  {
-    utf16String.resize(utf16StringLength);
-    utf16StringLength = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), length, &utf16String[0], utf16StringLength);
-    return utf16String;
-  }
-  std::runtime_error("ToUTF16String failed. Can't determine the length of the buffer needed\n");
-  return 0;
+
+  DWORD utf16StringLength = MultiByteToWideChar(CP_UTF8, 0, str.c_str(), length, NULL, 0);
+  if (utf16StringLength == 0)
+    throw std::runtime_error("ToUTF16String failed. Can't determine the length of the buffer needed.");
+
+  std::wstring utf16String(utf16StringLength, L'\0');
+  MultiByteToWideChar(CP_UTF8, 0, str.c_str(), length, &utf16String[0], utf16StringLength);
+  return utf16String;
 }
 
-
-
-std::string Utils::ToUTF8String(const std::wstring& str, unsigned long length)
+std::string Utils::ToUTF8String(const std::wstring& str)
 {
+  size_t length = str.size();
   if (length == 0)
     return std::string();
 
-  DWORD utf8StringLength = 0;
-  std::string utf8String;
-  utf8StringLength = WideCharToMultiByte(CP_UTF8, 0, str.c_str(), length, &utf8String[0], utf8StringLength, 0, 0);
-  if (utf8StringLength > 0)
-  {
-    utf8String.resize(utf8StringLength);
-    utf8StringLength = WideCharToMultiByte(CP_UTF8, 0, str.c_str(), length, &utf8String[0], utf8StringLength, 0, 0);
-    return utf8String;
-  }
-  std::runtime_error("ToUTF8String failed. Can't determine the length of the buffer needed\n");
-  return 0;
+  DWORD utf8StringLength = WideCharToMultiByte(CP_UTF8, 0, str.c_str(), length, NULL, 0, 0, 0);
+  if (utf8StringLength == 0)
+    throw std::runtime_error("ToUTF8String failed. Can't determine the length of the buffer needed.");
+
+  std::string utf8String(utf8StringLength, '\0');
+  WideCharToMultiByte(CP_UTF8, 0, str.c_str(), length, &utf8String[0], utf8StringLength, 0, 0);
+  return utf8String;
 }
 
 std::wstring Utils::CanonizeUrl(std::wstring url)
 {
   HRESULT hr;
 
   std::wstring canonizedUrl;
   DWORD canonizedUrlLength = 2049; // de-facto limit of url length
 
   canonizedUrl.resize(canonizedUrlLength);
@@ skipping 15 matching lines @@
 std::wstring Utils::TrimString(std::wstring text)
 {
   // Via http://stackoverflow.com/questions/216823/whats-the-best-way-to-trim-stdstring
   std::wstring trimmed(text);
   trimmed.erase(trimmed.begin(), std::find_if(trimmed.begin(), trimmed.end(), std::not1(std::ptr_fun<int, int>(std::isspace))));
   trimmed.erase(std::find_if(trimmed.rbegin(), trimmed.rend(), std::not1(std::ptr_fun<int, int>(std::isspace))).base(), trimmed.end());
   return trimmed;
 }
 
 #endif