EsenthalEngine/ThirdPartyLibs/LZHAM/Source/lzham_dynamic_lib.h

#pragma once

#define LZHAM_DYNAMIC_LIB 1
#include "lzham.h"

#ifdef _XBOX
   #define LZHAM_DLL_FILENAME       "lzham_x360.dll"
   #define LZHAM_DEBUG_DLL_FILENAME "lzham_x360D.dll"
#else
   // FIXME: This stuff should probably be moved to another header.
   #if LZHAM_64BIT
      #define LZHAM_DLL_FILENAME       "lzham_x64.dll"
      #define LZHAM_DEBUG_DLL_FILENAME "lzham_x64D.dll"
   #else
      #define LZHAM_DLL_FILENAME       "lzham_x86.dll"
      #define LZHAM_DEBUG_DLL_FILENAME "lzham_x86D.dll"
   #endif
#endif

#ifdef __cplusplus
// Simple helper class that demonstrates how to dynamically load the LZHAM DLL.
// The load() method loads the DLL, then initializes the member function pointers in ilzham by calling GetProcAddress() on all exported API's defined in lzham_exports.inc.
class lzham_dll_loader : public ilzham
{
   lzham_dll_loader(const lzham_dll_loader &other);
   lzham_dll_loader& operator= (const lzham_dll_loader &rhs);

public:
   lzham_dll_loader() : ilzham(), m_handle(NULL), m_win32_error(S_OK)
   {
   }

   virtual ~lzham_dll_loader()
   {
      unload();
   }

   enum
   {
      cErrorMissingExport = MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x201),
      cErrorUnsupportedDLLVersion = MAKE_HRESULT(SEVERITY_ERROR, FACILITY_ITF, 0x202),
   };

   // Assumes LZHAM DLL is in the same path as the executable.
#if defined(_XBOX) || defined(_MSC_VER)
   static void create_module_path(char *pModulePath, int size_in_chars, bool debug_dll)
   {
#ifdef _XBOX   
      char *buf = "D:\\unused.xex";
#else      
      char buf[MAX_PATH];
      GetModuleFileNameA(NULL, buf, sizeof(buf));
#endif
      char drive_buf[_MAX_DRIVE], dir_buf[_MAX_DIR], filename_buf[_MAX_FNAME], ext_buf[_MAX_EXT];
      _splitpath_s(buf, drive_buf, _MAX_DRIVE, dir_buf, _MAX_DIR, NULL, 0, NULL, 0);
      _splitpath_s(debug_dll ? LZHAM_DEBUG_DLL_FILENAME : LZHAM_DLL_FILENAME, NULL, 0, NULL, 0, filename_buf, _MAX_FNAME, ext_buf, _MAX_EXT);
      _makepath_s(pModulePath, size_in_chars, drive_buf, dir_buf, filename_buf, ext_buf);
   }
#else
   static void create_module_path(char *pModulePath, int size_in_chars, bool debug_dll)
   {
      strcpy(pModulePath, debug_dll ? LZHAM_DEBUG_DLL_FILENAME : LZHAM_DLL_FILENAME);
   }
#endif

   virtual bool load()
   {
      HRESULT hres = load(NULL);
      return S_OK == hres;
   }

   HRESULT load(const char* pModulePath)
   {
      unload();
      
      char buf[MAX_PATH];
      if (!pModulePath)
      {
         create_module_path(buf, sizeof(buf), false);
         pModulePath = buf;
      }
      
      m_win32_error = S_OK;

      m_handle = LoadLibraryA(pModulePath);
      if (NULL == m_handle)
      {
         m_win32_error = HRESULT_FROM_WIN32(GetLastError());
         return m_win32_error;
      }

      struct
      {
         const char* pName;
         void** pFunc_ptr;
      }
      funcs[] =
      {
#define LZHAM_DLL_FUNC_NAME(x) { #x, (void**)&x },
#include "lzham_exports.inc"
#undef LZHAM_DLL_FUNC_NAME
      };

      const int cNumFuncs = sizeof(funcs) / sizeof(funcs[0]);

      for (int i = 0; i < cNumFuncs; i++)
      {
#ifdef _XBOX
         if ((*funcs[i].pFunc_ptr = GetProcAddress(m_handle, (LPCSTR)(i + 1))) == NULL)
#else      
         if ((*funcs[i].pFunc_ptr = (void*)GetProcAddress(m_handle, funcs[i].pName)) == NULL)
#endif         
         {
            unload();
            
            m_win32_error = cErrorMissingExport;
            return m_win32_error;
         }
      }

      int dll_ver = lzham_get_version();

      // Ensure DLL's major version is the expected version.
      if ((dll_ver >> 8U) != (LZHAM_DLL_VERSION >> 8U))
      {
         unload();
         
         m_win32_error = cErrorUnsupportedDLLVersion;
         return m_win32_error;
      }

      return S_OK;
   }

   virtual void unload()
   {
      if (m_handle)
      {
         FreeLibrary(m_handle);
         m_handle = NULL;
      }
            
      clear();
      
      m_win32_error = S_OK;
   }
   
   virtual bool is_loaded() { return m_handle != NULL; }
   
   HRESULT get_last_win32_error() { return m_win32_error; }
   
private:
   HMODULE m_handle;
   HRESULT m_win32_error;
};
#endif // #ifdef __cplusplus