glapi.c

winNT技术操作系统,国外开放的原代码和LIUX一样

 *                             passed to the named function.  Parameter types
 *                             are converted to characters using the following
 *                             rules:
 *                               - 'i' for \c GLint, \c GLuint, and \c GLenum
 *                               - 'p' for any pointer type
 *                               - 'f' for \c GLfloat and \c GLclampf
 *                               - 'd' for \c GLdouble and \c GLclampd
 *
 * \returns
 * The offset in the dispatch table of the named function.  A pointer to the
 * driver's implementation of the named function should be stored at
 * \c dispatch_table[\c offset].
 *
 * \sa glXGetProcAddress
 *
 * \warning
 * This function can only handle up to 8 names at a time.  As far as I know,
 * the maximum number of names ever associated with an existing GL function is
 * 4 (\c glPointParameterfSGIS, \c glPointParameterfEXT,
 * \c glPointParameterfARB, and \c glPointParameterf), so this should not be
 * too painful of a limitation.
 *
 * \todo
 * Determine whether or not \c parameter_signature should be allowed to be
 * \c NULL.  It doesn't seem like much of a hardship for drivers to have to
 * pass in an empty string.
 *
 * \todo
 * Determine if code should be added to reject function names that start with
 * 'glX'.
 * 
 * \bug
 * Add code to compare \c parameter_signature with the parameter signature of
 * a static function.  In order to do that, we need to find a way to \b get
 * the parameter signature of a static function.
 */

PUBLIC int
_glapi_add_dispatch( const char * const * function_names,
		     const char * parameter_signature )
{
   static int next_dynamic_offset = _gloffset_FIRST_DYNAMIC;
   const char * const real_sig = (parameter_signature != NULL)
     ? parameter_signature : "";
   struct _glapi_function * entry[8];
   GLboolean is_static[8];
   unsigned i;
   unsigned j;
   int offset = ~0;
   int new_offset;


   (void) memset( is_static, 0, sizeof( is_static ) );
   (void) memset( entry, 0, sizeof( entry ) );

   for ( i = 0 ; function_names[i] != NULL ; i++ ) {
      /* Do some trivial validation on the name of the function.
       */

#ifdef MANGLE
      if (!function_names[i] || function_names[i][0] != 'm' || function_names[i][1] != 'g' || function_names[i][2] != 'l')
	return GL_FALSE;
#else
      if (!function_names[i] || function_names[i][0] != 'g' || function_names[i][1] != 'l')
	return GL_FALSE;
#endif
   
   
      /* Determine if the named function already exists.  If the function does
       * exist, it must have the same parameter signature as the function
       * being added.
       */

      new_offset = get_static_proc_offset(function_names[i]);
      if (new_offset >= 0) {
	 /* FIXME: Make sure the parameter signatures match!  How do we get
	  * FIXME: the parameter signature for static functions?
	  */

	 if ( (offset != ~0) && (new_offset != offset) ) {
	    return -1;
	 }

	 is_static[i] = GL_TRUE;
	 offset = new_offset;
      }
   
   
      for ( j = 0 ; j < NumExtEntryPoints ; j++ ) {
	 if (strcmp(ExtEntryTable[j].name, function_names[i]) == 0) {
	    /* The offset may be ~0 if the function name was added by
	     * glXGetProcAddress but never filled in by the driver.
	     */

	    if (ExtEntryTable[j].dispatch_offset != ~0) {
	       if (strcmp(real_sig, ExtEntryTable[j].parameter_signature) 
		   != 0) {
		  return -1;
	       }

	       if ( (offset != ~0) && (ExtEntryTable[j].dispatch_offset != offset) ) {
		  return -1;
	       }

	       offset = ExtEntryTable[j].dispatch_offset;
	    }
	    
	    entry[i] = & ExtEntryTable[j];
	    break;
	 }
      }
   }


   if (offset == ~0) {
      offset = next_dynamic_offset;
      next_dynamic_offset++;
   }


   for ( i = 0 ; function_names[i] != NULL ; i++ ) {
      if (! is_static[i] ) {
	 if (entry[i] == NULL) {
	    entry[i] = add_function_name( function_names[i] );
	    if (entry[i] == NULL) {
	       /* FIXME: Possible memory leak here.
		*/
	       return -1;
	    }
	 }


	 entry[i]->parameter_signature = str_dup(real_sig);
	 fill_in_entrypoint_offset(entry[i]->dispatch_stub, offset);
	 entry[i]->dispatch_offset = offset;
      }
   }
   
   return offset;
}


/**
 * Return offset of entrypoint for named function within dispatch table.
 */
PUBLIC GLint
_glapi_get_proc_offset(const char *funcName)
{
   /* search extension functions first */
   GLuint i;
   for (i = 0; i < NumExtEntryPoints; i++) {
      if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
         return ExtEntryTable[i].dispatch_offset;
      }
   }

   /* search static functions */
   return get_static_proc_offset(funcName);
}



/**
 * Return pointer to the named function.  If the function name isn't found
 * in the name of static functions, try generating a new API entrypoint on
 * the fly with assembly language.
 */
_glapi_proc
_glapi_get_proc_address(const char *funcName)
{
   struct _glapi_function * entry;
   GLuint i;

#ifdef MANGLE
   if (funcName[0] != 'm' || funcName[1] != 'g' || funcName[2] != 'l')
      return NULL;
#else
   if (funcName[0] != 'g' || funcName[1] != 'l')
      return NULL;
#endif

   /* search extension functions first */
   for (i = 0; i < NumExtEntryPoints; i++) {
      if (strcmp(ExtEntryTable[i].name, funcName) == 0) {
         return ExtEntryTable[i].dispatch_stub;
      }
   }

#if !defined( XFree86Server )
   /* search static functions */
   {
      const _glapi_proc func = get_static_proc_address(funcName);
      if (func)
         return func;
   }
#endif /* !defined( XFree86Server ) */

   entry = add_function_name(funcName);
   return (entry == NULL) ? NULL : entry->dispatch_stub;
}



/**
 * Return the name of the function at the given dispatch offset.
 * This is only intended for debugging.
 */
const char *
_glapi_get_proc_name(GLuint offset)
{
   GLuint i;
   const char * n;

   /* search built-in functions */
   n = get_static_proc_name(offset);
   if ( n != NULL ) {
      return n;
   }

   /* search added extension functions */
   for (i = 0; i < NumExtEntryPoints; i++) {
      if (ExtEntryTable[i].dispatch_offset == offset) {
         return ExtEntryTable[i].name;
      }
   }
   return NULL;
}



/**
 * Return size of dispatch table struct as number of functions (or
 * slots).
 */
PUBLIC GLuint
_glapi_get_dispatch_table_size(void)
{
   return DISPATCH_TABLE_SIZE;
}



/**
 * Make sure there are no NULL pointers in the given dispatch table.
 * Intended for debugging purposes.
 */
void
_glapi_check_table(const struct _glapi_table *table)
{
#ifdef DEBUG
   const GLuint entries = _glapi_get_dispatch_table_size();
   const void **tab = (const void **) table;
   GLuint i;
   for (i = 1; i < entries; i++) {
      assert(tab[i]);
   }

   /* Do some spot checks to be sure that the dispatch table
    * slots are assigned correctly.
    */
   {
      GLuint BeginOffset = _glapi_get_proc_offset("glBegin");
      char *BeginFunc = (char*) &table->Begin;
      GLuint offset = (BeginFunc - (char *) table) / sizeof(void *);
      assert(BeginOffset == _gloffset_Begin);
      assert(BeginOffset == offset);
   }
   {
      GLuint viewportOffset = _glapi_get_proc_offset("glViewport");
      char *viewportFunc = (char*) &table->Viewport;
      GLuint offset = (viewportFunc - (char *) table) / sizeof(void *);
      assert(viewportOffset == _gloffset_Viewport);
      assert(viewportOffset == offset);
   }
   {
      GLuint VertexPointerOffset = _glapi_get_proc_offset("glVertexPointer");
      char *VertexPointerFunc = (char*) &table->VertexPointer;
      GLuint offset = (VertexPointerFunc - (char *) table) / sizeof(void *);
      assert(VertexPointerOffset == _gloffset_VertexPointer);
      assert(VertexPointerOffset == offset);
   }
   {
      GLuint ResetMinMaxOffset = _glapi_get_proc_offset("glResetMinmax");
      char *ResetMinMaxFunc = (char*) &table->ResetMinmax;
      GLuint offset = (ResetMinMaxFunc - (char *) table) / sizeof(void *);
      assert(ResetMinMaxOffset == _gloffset_ResetMinmax);
      assert(ResetMinMaxOffset == offset);
   }
   {
      GLuint blendColorOffset = _glapi_get_proc_offset("glBlendColor");
      char *blendColorFunc = (char*) &table->BlendColor;
      GLuint offset = (blendColorFunc - (char *) table) / sizeof(void *);
      assert(blendColorOffset == _gloffset_BlendColor);
      assert(blendColorOffset == offset);
   }
   {
      GLuint istextureOffset = _glapi_get_proc_offset("glIsTextureEXT");
      char *istextureFunc = (char*) &table->IsTextureEXT;
      GLuint offset = (istextureFunc - (char *) table) / sizeof(void *);
      assert(istextureOffset == _gloffset_IsTextureEXT);
      assert(istextureOffset == offset);
   }
   {
      GLuint secondaryColor3fOffset = _glapi_get_proc_offset("glSecondaryColor3fEXT");
      char *secondaryColor3fFunc = (char*) &table->SecondaryColor3fEXT;
      GLuint offset = (secondaryColor3fFunc - (char *) table) / sizeof(void *);
      assert(secondaryColor3fOffset == _gloffset_SecondaryColor3fEXT);
      assert(secondaryColor3fOffset == offset);
      assert(_glapi_get_proc_address("glSecondaryColor3fEXT") == (_glapi_proc) &glSecondaryColor3fEXT);
   }
   {
      GLuint pointParameterivOffset = _glapi_get_proc_offset("glPointParameterivNV");
      char *pointParameterivFunc = (char*) &table->PointParameterivNV;
      GLuint offset = (pointParameterivFunc - (char *) table) / sizeof(void *);
      assert(pointParameterivOffset == _gloffset_PointParameterivNV);
      assert(pointParameterivOffset == offset);
      assert(_glapi_get_proc_address("glPointParameterivNV") == (_glapi_proc) &glPointParameterivNV);
   }
   {
      GLuint setFenceOffset = _glapi_get_proc_offset("glSetFenceNV");
      char *setFenceFunc = (char*) &table->SetFenceNV;
      GLuint offset = (setFenceFunc - (char *) table) / sizeof(void *);
      assert(setFenceOffset == _gloffset_SetFenceNV);
      assert(setFenceOffset == offset);
      assert(_glapi_get_proc_address("glSetFenceNV") == (_glapi_proc) &glSetFenceNV);
   }
#else
   (void) table;
#endif
}


/**
 * Perform platform-specific GL API entry-point fixups.
 * 
 * 
 */
static void
init_glapi_relocs( void )
{
#if defined( USE_X86_ASM ) && defined( GLX_USE_TLS )
    extern void * _x86_get_dispatch(void);
    const GLubyte * const get_disp = (const GLubyte *) _x86_get_dispatch;
    GLubyte * curr_func = (GLubyte *) gl_dispatch_functions_start;


    while ( curr_func != (GLubyte *) gl_dispatch_functions_end ) {
	(void) memcpy( curr_func, get_disp, 6 );
	curr_func += X86_DISPATCH_FUNCTION_SIZE;
    }
#endif /* defined( USE_X86_ASM ) && defined( GLX_USE_TLS ) */
}