swfdec_as_types.c

Swfdec is a decoder/renderer for Macromedia Flash animations. The decoding and rendering engine is

	if (*end == 'e') {
	  /* 'e' */
	  *start++ = *end++;
	  /* + or - */
	  *start++ = *end++;
	  /* skip 0s */
	  while (*end == '0')
	    end++;
	  /* add rest */
	  while (*end != 0)
	    *start++ = *end++;
	}
	/* end string */
	*start = 0;
	return swfdec_as_context_get_string (context, s);
      }
  }
}

/**
 * swfdec_as_value_to_string:
 * @context: a #SwfdecAsContext
 * @value: value to be expressed as string
 *
 * Converts @value to a string according to the rules of Flash. This might 
 * cause calling back into the script engine if the @value is an object. In
 * that case, the object's valueOf function is called. 
 * <warning>Never use this function for debugging purposes.</warning>
 *
 * Returns: a garbage-collected string representing @value. The value will 
 *          never be %NULL.
 **/
const char *
swfdec_as_value_to_string (SwfdecAsContext *context, const SwfdecAsValue *value)
{
  g_return_val_if_fail (SWFDEC_IS_AS_CONTEXT (context), SWFDEC_AS_STR_EMPTY);
  g_return_val_if_fail (SWFDEC_IS_AS_VALUE (value), SWFDEC_AS_STR_EMPTY);

  switch (value->type) {
    case SWFDEC_AS_TYPE_STRING:
      return SWFDEC_AS_VALUE_GET_STRING (value);
    case SWFDEC_AS_TYPE_UNDEFINED:
      if (context->version > 6)
	return SWFDEC_AS_STR_undefined;
      else
	return SWFDEC_AS_STR_EMPTY;
    case SWFDEC_AS_TYPE_BOOLEAN:
      return SWFDEC_AS_VALUE_GET_BOOLEAN (value) ? SWFDEC_AS_STR_true : SWFDEC_AS_STR_false;
    case SWFDEC_AS_TYPE_NULL:
      return SWFDEC_AS_STR_null;
    case SWFDEC_AS_TYPE_NUMBER:
      return swfdec_as_double_to_string (context, SWFDEC_AS_VALUE_GET_NUMBER (value));
    case SWFDEC_AS_TYPE_OBJECT:
      {
	SwfdecAsObject *object = SWFDEC_AS_VALUE_GET_OBJECT (value);
	if (SWFDEC_IS_MOVIE (object)) {
	  char *str = swfdec_movie_get_path (SWFDEC_MOVIE (object));
	  const char *ret = swfdec_as_context_get_string (context, str);
	  g_free (str);
	  return ret;
	} else {
	  SwfdecAsValue ret;
	  swfdec_as_object_call (object, SWFDEC_AS_STR_toString, 0, NULL, &ret);
	  if (SWFDEC_AS_VALUE_IS_STRING (&ret))
	    return SWFDEC_AS_VALUE_GET_STRING (&ret);
	  else if (SWFDEC_IS_AS_SUPER (SWFDEC_AS_VALUE_GET_OBJECT (value)))
	    return SWFDEC_AS_STR__type_Object_;
	  else if (SWFDEC_IS_AS_FUNCTION (SWFDEC_AS_VALUE_GET_OBJECT (value)))
	    return SWFDEC_AS_STR__type_Function_;
	  else
	    return SWFDEC_AS_STR__type_Object_;
	}
      }
    default:
      g_assert_not_reached ();
      return SWFDEC_AS_STR_EMPTY;
  }
}

/**
 * swfdec_as_value_to_debug:
 * @value: a #SwfdecAsValue
 *
 * Converts the given @value to a string in a safe way. It will not call into
 * the scripting engine. Its intended use is for output in debuggers.
 *
 * Returns: a newly allocated string. Free with g_free().
 **/
char *
swfdec_as_value_to_debug (const SwfdecAsValue *value)
{
  g_return_val_if_fail (SWFDEC_IS_AS_VALUE (value), NULL);

  switch (value->type) {
    case SWFDEC_AS_TYPE_STRING:
      return g_shell_quote (SWFDEC_AS_VALUE_GET_STRING (value));
    case SWFDEC_AS_TYPE_UNDEFINED:
      return g_strdup ("undefined");
    case SWFDEC_AS_TYPE_BOOLEAN:
      return g_strdup (SWFDEC_AS_VALUE_GET_BOOLEAN (value) ? "true" : "false");
    case SWFDEC_AS_TYPE_NULL:
      return g_strdup ("null");
    case SWFDEC_AS_TYPE_NUMBER:
      return g_strdup_printf ("%g", SWFDEC_AS_VALUE_GET_NUMBER (value));
    case SWFDEC_AS_TYPE_OBJECT:
      return swfdec_as_object_get_debug (SWFDEC_AS_VALUE_GET_OBJECT (value));
    default:
      g_assert_not_reached ();
      return NULL;
  }
}

/**
 * swfdec_as_value_to_number:
 * @context: a #SwfdecAsContext
 * @value: a #SwfdecAsValue used by context
 *
 * Converts the value to a number according to Flash's conversion routines and
 * the current Flash version. This conversion routine is similar, but not equal
 * to ECMAScript. For objects, it can call back into the script engine by 
 * calling the object's valueOf function.
 *
 * Returns: a double value. It can be NaN or +-Infinity. It will not be -0.0.
 **/
double
swfdec_as_value_to_number (SwfdecAsContext *context, const SwfdecAsValue *value)
{
  SwfdecAsValue tmp;

  g_return_val_if_fail (SWFDEC_IS_AS_CONTEXT (context), 0.0);
  g_return_val_if_fail (SWFDEC_IS_AS_VALUE (value), 0.0);

  tmp = *value;
  swfdec_as_value_to_primitive (&tmp);

  switch (tmp.type) {
    case SWFDEC_AS_TYPE_UNDEFINED:
    case SWFDEC_AS_TYPE_NULL:
      return (context->version >= 7) ? NAN : 0.0;
    case SWFDEC_AS_TYPE_BOOLEAN:
      return SWFDEC_AS_VALUE_GET_BOOLEAN (&tmp) ? 1 : 0;
    case SWFDEC_AS_TYPE_NUMBER:
      return SWFDEC_AS_VALUE_GET_NUMBER (&tmp);
    case SWFDEC_AS_TYPE_STRING:
      {
	const char *s;
	char *end;
	double d;
	
	s = SWFDEC_AS_VALUE_GET_STRING (&tmp);
	if (s == SWFDEC_AS_STR_EMPTY)
	  return NAN;
	d = g_ascii_strtod (s, &end);
	if (*end == '\0')
	  return d == -0.0 ? 0.0 : d;
	else
	  return NAN;
      }
    case SWFDEC_AS_TYPE_OBJECT:
      return NAN;
    default:
      g_assert_not_reached ();
      return NAN;
  }
}

/**
 * swfdec_as_value_to_integer:
 * @context: a #SwfdecAsContext
 * @value: value to convert
 *
 * Converts the given value to an integer. This is done similar to the 
 * conversion used by swfdec_as_value_to_number().
 *
 * Returns: An Integer that can be represented in 32 bits.
 **/
int
swfdec_as_value_to_integer (SwfdecAsContext *context, const SwfdecAsValue *value)
{
  double d;
  
  d = swfdec_as_value_to_number (context, value);
  if (!isfinite (d))
    return 0;
  if (d < 0) {
    d = fmod (-d, 4294967296.0);
    return - (guint) d;
  } else {
    d = fmod (d, 4294967296.0);
    return (guint) d;
  }
}

/**
 * swfdec_as_value_to_object:
 * @context: a #SwfdecAsContext
 * @value: value to convert
 *
 * Converts a given value to its representation as an object. The object 
 * representation for primitive types is a wrapper object of the corresponding 
 * class (Number for numbers, String for strings, Boolean for bools). If the 
 * value does not have an object representing it, such as undefined and null 
 * values, %NULL is returned.
 *
 * Returns: object representing @value or %NULL.
 **/
SwfdecAsObject *
swfdec_as_value_to_object (SwfdecAsContext *context, const SwfdecAsValue *value)
{
  SwfdecAsFunction *fun;
  SwfdecAsValue val;
  const char *s;

  g_return_val_if_fail (SWFDEC_IS_AS_CONTEXT (context), NULL);
  g_return_val_if_fail (SWFDEC_IS_AS_VALUE (value), NULL);

  switch (value->type) {
    case SWFDEC_AS_TYPE_UNDEFINED:
    case SWFDEC_AS_TYPE_NULL:
      return NULL;
    case SWFDEC_AS_TYPE_NUMBER:
      s = SWFDEC_AS_STR_Number;
      break;
    case SWFDEC_AS_TYPE_STRING:
      s = SWFDEC_AS_STR_String;
      break;
    case SWFDEC_AS_TYPE_BOOLEAN:
      s = SWFDEC_AS_STR_Boolean;
      break;
    case SWFDEC_AS_TYPE_OBJECT:
      return SWFDEC_AS_VALUE_GET_OBJECT (value);
    default:
      g_assert_not_reached ();
      return NULL;
  }

  swfdec_as_object_get_variable (context->global, s, &val);
  if (!SWFDEC_AS_VALUE_IS_OBJECT (&val) ||
      !SWFDEC_IS_AS_FUNCTION (fun = (SwfdecAsFunction *) SWFDEC_AS_VALUE_GET_OBJECT (&val)))
    return NULL;
  swfdec_as_object_create (fun, 1, value);
  swfdec_as_context_run (context);
  value = swfdec_as_stack_pop (context);
  if (SWFDEC_AS_VALUE_IS_OBJECT (value)) {
    return SWFDEC_AS_VALUE_GET_OBJECT (value);
  } else {
    SWFDEC_ERROR ("did not construct an object");
    return NULL;
  }
}

/**
* swfdec_as_value_to_boolean:
* @context: a #SwfdecAsContext
* @value: value to convert
*
* Converts the given value to a boolean according to Flash's rules. Note that
* these rules changed significantly for strings between Flash 6 and 7.
*
* Returns: either %TRUE or %FALSE.
**/
gboolean
swfdec_as_value_to_boolean (SwfdecAsContext *context, const SwfdecAsValue *value)
{
  g_return_val_if_fail (SWFDEC_IS_AS_CONTEXT (context), FALSE);
  g_return_val_if_fail (SWFDEC_IS_AS_VALUE (value), FALSE);

  /* FIXME: what do we do when called in flash 4? */
  switch (value->type) {
    case SWFDEC_AS_TYPE_UNDEFINED:
    case SWFDEC_AS_TYPE_NULL:
      return FALSE;
    case SWFDEC_AS_TYPE_BOOLEAN:
      return SWFDEC_AS_VALUE_GET_BOOLEAN (value);
    case SWFDEC_AS_TYPE_NUMBER:
      {
	double d = SWFDEC_AS_VALUE_GET_NUMBER (value);
	return d != 0.0 && !isnan (d);
      }
    case SWFDEC_AS_TYPE_STRING:
      if (context->version <= 6) {
	double d = swfdec_as_value_to_number (context, value);
	return d != 0.0 && !isnan (d);
      } else {
	return SWFDEC_AS_VALUE_GET_STRING (value) != SWFDEC_AS_STR_EMPTY;
      }
    case SWFDEC_AS_TYPE_OBJECT:
      return TRUE;
    default:
      g_assert_not_reached ();
      return FALSE;
  }
}

/**
* swfdec_as_value_to_primitive:
* @value: value to convert
*
* Tries to convert the given @value inline to its primitive value. Primitive 
* values are values that are not objects. If the value is an object, the 
* object's valueOf function is called. If the result of that function is still 
* an object, it is returned nonetheless.
**/
void
swfdec_as_value_to_primitive (SwfdecAsValue *value)
{
  g_return_if_fail (SWFDEC_IS_AS_VALUE (value));

  if (SWFDEC_AS_VALUE_IS_OBJECT (value) && !SWFDEC_IS_MOVIE (SWFDEC_AS_VALUE_GET_OBJECT (value))) {
    swfdec_as_object_call (SWFDEC_AS_VALUE_GET_OBJECT (value), SWFDEC_AS_STR_valueOf,
	0, NULL, value);
  }
}