text: //
  // Copyright (c) 2008-2021 the Urho3D project.
  //
  // Permission is hereby granted, free of charge, to any person obtaining a copy
  // of this software and associated documentation files (the "Software"), to deal
  // in the Software without restriction, including without limitation the rights
  // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  // copies of the Software, and to permit persons to whom the Software is
  // furnished to do so, subject to the following conditions:
  //
  // The above copyright notice and this permission notice shall be included in
  // all copies or substantial portions of the Software.
  //
  // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  // THE SOFTWARE.
  //
  
  #include "../Precompiled.h"
  
  #include "../Math/MathDefs.h"
  #include "../Math/StringHash.h"
  #include "../Container/HashMap.h"
  #include "../Core/StringHashRegister.h"
  #include "../IO/Log.h"
  
  #include <cstdio>
  
  #include "../DebugNew.h"
  
  namespace Urho3D
  {
  
  #ifdef URHO3D_HASH_DEBUG
  
  // Expose map to let Visual Studio debugger access it if Urho3D is linked statically.
  const StringMap* hashReverseMap = nullptr;
  
  // Hide static global variables in functions to ensure initialization order.
  static StringHashRegister& GetGlobalStringHashRegister()
  {
      static StringHashRegister stringHashRegister(true /*thread safe*/ );
      hashReverseMap = &stringHashRegister.GetInternalMap();
      return stringHashRegister;
  }
  
  #endif
  
  const StringHash StringHash::ZERO;
  
  StringHash::StringHash(const char* str) noexcept :
      value_(Calculate(str))
  {
  #ifdef URHO3D_HASH_DEBUG
      Urho3D::GetGlobalStringHashRegister().RegisterString(*this, str);
  #endif
  }
  
  StringHash::StringHash(const String& str) noexcept :
      value_(Calculate(str.CString()))
  {
  #ifdef URHO3D_HASH_DEBUG
      Urho3D::GetGlobalStringHashRegister().RegisterString(*this, str.CString());
  #endif
  }
  
  unsigned StringHash::Calculate(const char* str, unsigned hash)
  {
      if (!str)
          return hash;
  
      while (*str)
      {
          hash = SDBMHash(hash, (unsigned char)*str++);
      }
  
      return hash;
  }
  
  StringHashRegister* StringHash::GetGlobalStringHashRegister()
  {
  #ifdef URHO3D_HASH_DEBUG
      return &Urho3D::GetGlobalStringHashRegister();
  #else
      return nullptr;
  #endif
  }
  
  String StringHash::ToString() const
  {
      char tempBuffer[CONVERSION_BUFFER_LENGTH];
      sprintf(tempBuffer, "%08X", value_);
      return String(tempBuffer);
  }
  
  String StringHash::Reverse() const
  {
  #ifdef URHO3D_HASH_DEBUG
      return Urho3D::GetGlobalStringHashRegister().GetStringCopy(*this);
  #else
      return String::EMPTY;
  #endif
  }
  
  }
  