jerryscript/jerry-core/ecma/builtin-objects/ecma-builtin-helpers.c

/* Copyright JS Foundation and other contributors, http://js.foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "ecma-builtin-helpers.h"

#include "ecma-alloc.h"
#include "ecma-array-object.h"
#include "ecma-builtins.h"
#include "ecma-conversion.h"
#include "ecma-function-object.h"
#include "ecma-exceptions.h"
#include "ecma-gc.h"
#include "ecma-helpers.h"
#include "jmem.h"
#include "ecma-objects.h"
#include "ecma-try-catch-macro.h"
#include "lit-magic-strings.h"

/** \addtogroup ecma ECMA
 * @{
 *
 * \addtogroup ecmabuiltinhelpers ECMA builtin helper operations
 * @{
 */

#if ENABLED (JERRY_ES2015)
/**
 * Helper function for Object.prototype.toString routine when
 * the @@toStringTag property is present
 *
 * See also:
 *          ECMA-262 v6, 19.1.3.6
 *
 * @return ecma value
 *         Returned value must be freed with ecma_free_value.
 */
static ecma_value_t
ecma_builtin_helper_object_to_string_tag_helper (ecma_value_t tag_value) /**< string tag */
{
  JERRY_ASSERT (ecma_is_value_string (tag_value));

  ecma_string_t *tag_str_p = ecma_get_string_from_value (tag_value);
  ecma_string_t *ret_string_p;

  /* Building string "[object #@@toStringTag#]"
     The string size will be size("[object ") + size(#@@toStringTag#) + size ("]"). */
  const lit_utf8_size_t buffer_size = 9 + ecma_string_get_size (tag_str_p);
  JMEM_DEFINE_LOCAL_ARRAY (str_buffer, buffer_size, lit_utf8_byte_t);

  lit_utf8_byte_t *buffer_ptr = str_buffer;

  const lit_magic_string_id_t magic_string_ids[] =
  {
    LIT_MAGIC_STRING_LEFT_SQUARE_CHAR,
    LIT_MAGIC_STRING_OBJECT,
    LIT_MAGIC_STRING_SPACE_CHAR,
  };

  /* Copy to buffer the "[object " string */
  for (uint32_t i = 0; i < sizeof (magic_string_ids) / sizeof (lit_magic_string_id_t); ++i)
  {
    buffer_ptr = lit_copy_magic_string_to_buffer (magic_string_ids[i], buffer_ptr,
                                                  (lit_utf8_size_t) ((str_buffer + buffer_size) - buffer_ptr));

    JERRY_ASSERT (buffer_ptr <= str_buffer + buffer_size);
  }

  /* Copy to buffer the #@@toStringTag# string */
  buffer_ptr += ecma_string_copy_to_cesu8_buffer (tag_str_p, buffer_ptr,
                                                  (lit_utf8_size_t) ((str_buffer + buffer_size) - buffer_ptr));

  JERRY_ASSERT (buffer_ptr <= str_buffer + buffer_size);

  /* Copy to buffer the "]" string */
  buffer_ptr = lit_copy_magic_string_to_buffer (LIT_MAGIC_STRING_RIGHT_SQUARE_CHAR, buffer_ptr,
                                                (lit_utf8_size_t) ((str_buffer + buffer_size) - buffer_ptr));

  JERRY_ASSERT (buffer_ptr <= str_buffer + buffer_size);

  ret_string_p = ecma_new_ecma_string_from_utf8 (str_buffer, (lit_utf8_size_t) (buffer_ptr - str_buffer));

  JMEM_FINALIZE_LOCAL_ARRAY (str_buffer);
  ecma_deref_ecma_string (tag_str_p);

  return ecma_make_string_value (ret_string_p);
} /* ecma_builtin_helper_object_to_string_tag_helper */
#endif /* ENABLED (JERRY_ES2015) */

/**
 * Common implementation of the Object.prototype.toString routine
 *
 * See also:
 *          ECMA-262 v5, 15.2.4.2
 *
 * Used by:
 *         - The Object.prototype.toString routine.
 *         - The Array.prototype.toString routine as fallback.
 *
 * @return ecma value
 *         Returned value must be freed with ecma_free_value.
 */

ecma_value_t
ecma_builtin_helper_object_to_string (const ecma_value_t this_arg) /**< this argument */
{
  lit_magic_string_id_t type_string;

  if (ecma_is_value_undefined (this_arg))
  {
    type_string = LIT_MAGIC_STRING_UNDEFINED_UL;
  }
  else if (ecma_is_value_null (this_arg))
  {
    type_string = LIT_MAGIC_STRING_NULL_UL;
  }
  else
  {
    ecma_value_t obj_this = ecma_op_to_object (this_arg);

    if (ECMA_IS_VALUE_ERROR (obj_this))
    {
      return obj_this;
    }

    JERRY_ASSERT (ecma_is_value_object (obj_this));

    ecma_object_t *obj_p = ecma_get_object_from_value (obj_this);

    type_string = ecma_object_get_class_name (obj_p);

#if ENABLED (JERRY_ES2015)
    ecma_value_t tag_value = ecma_op_object_get_by_symbol_id (obj_p, LIT_MAGIC_STRING_TO_STRING_TAG);

    if (ECMA_IS_VALUE_ERROR (tag_value))
    {
      ecma_deref_object (obj_p);
      return tag_value;
    }

    if (ecma_is_value_string (tag_value))
    {
      ecma_deref_object (obj_p);
      return ecma_builtin_helper_object_to_string_tag_helper (tag_value);
    }

    ecma_free_value (tag_value);
#endif /* ENABLED (JERRY_ES2015) */

    ecma_deref_object (obj_p);
  }

  ecma_string_t *ret_string_p;

  /* Building string "[object #type#]" where type is 'Undefined',
     'Null' or one of possible object's classes.
     The string with null character is maximum 27 characters long. */
  const lit_utf8_size_t buffer_size = 27;
  JERRY_VLA (lit_utf8_byte_t, str_buffer, buffer_size);

  lit_utf8_byte_t *buffer_ptr = str_buffer;

  const lit_magic_string_id_t magic_string_ids[] =
  {
    LIT_MAGIC_STRING_LEFT_SQUARE_CHAR,
    LIT_MAGIC_STRING_OBJECT,
    LIT_MAGIC_STRING_SPACE_CHAR,
    type_string,
    LIT_MAGIC_STRING_RIGHT_SQUARE_CHAR
  };

  for (uint32_t i = 0; i < sizeof (magic_string_ids) / sizeof (lit_magic_string_id_t); ++i)
  {
    buffer_ptr = lit_copy_magic_string_to_buffer (magic_string_ids[i], buffer_ptr,
                                                  (lit_utf8_size_t) ((str_buffer + buffer_size) - buffer_ptr));
    JERRY_ASSERT (buffer_ptr <= str_buffer + buffer_size);
  }

  ret_string_p = ecma_new_ecma_string_from_utf8 (str_buffer, (lit_utf8_size_t) (buffer_ptr - str_buffer));

  return ecma_make_string_value (ret_string_p);
} /* ecma_builtin_helper_object_to_string */

/**
 * The Array.prototype's 'toLocaleString' single element operation routine
 *
 * See also:
 *          ECMA-262 v5, 15.4.4.3 steps 6-8 and 10.b-d
 *
 * @return ecma value
 *         Returned value must be freed with ecma_free_value.
 */
ecma_value_t
ecma_builtin_helper_get_to_locale_string_at_index (ecma_object_t *obj_p, /**< this object */
                                                   uint32_t index) /**< array index */
{
  ecma_value_t ret_value = ECMA_VALUE_EMPTY;
  ecma_string_t *index_string_p = ecma_new_ecma_string_from_uint32 (index);
  ecma_value_t index_value = ecma_op_object_get (obj_p, index_string_p);
  ecma_deref_ecma_string (index_string_p);

  if (ECMA_IS_VALUE_ERROR (index_value))
  {
    return index_value;
  }

  if (ecma_is_value_undefined (index_value) || ecma_is_value_null (index_value))
  {
    ecma_free_value (index_value);
    return ecma_make_magic_string_value (LIT_MAGIC_STRING__EMPTY);
  }

  ecma_value_t index_obj_value = ecma_op_to_object (index_value);

  ecma_free_value (index_value);

  if (ECMA_IS_VALUE_ERROR (index_obj_value))
  {
    return index_obj_value;
  }

  ecma_object_t *index_obj_p = ecma_get_object_from_value (index_obj_value);
  ecma_value_t to_locale_value = ecma_op_object_get_by_magic_id (index_obj_p, LIT_MAGIC_STRING_TO_LOCALE_STRING_UL);

  if (ECMA_IS_VALUE_ERROR (to_locale_value))
  {
    ecma_deref_object (index_obj_p);
    return to_locale_value;
  }

  if (ecma_op_is_callable (to_locale_value))
  {
    ecma_object_t *locale_func_obj_p = ecma_get_object_from_value (to_locale_value);

    ecma_value_t call_value = ecma_op_function_call (locale_func_obj_p,
                                                     ecma_make_object_value (index_obj_p),
                                                     NULL,
                                                     0);

    ecma_deref_object (locale_func_obj_p);
    ecma_deref_object (index_obj_p);

    if (ECMA_IS_VALUE_ERROR (call_value))
    {
      return call_value;
    }

    ecma_string_t *call_str_p = ecma_op_to_string (call_value);

    ecma_free_value (call_value);

    if (JERRY_UNLIKELY (call_str_p == NULL))
    {
      return ECMA_VALUE_ERROR;
    }

    ret_value = ecma_make_string_value (call_str_p);
  }
  else
  {
    ecma_free_value (to_locale_value);
    ecma_deref_object (index_obj_p);
    ret_value = ecma_raise_type_error (ECMA_ERR_MSG ("'toLocaleString' is missing or not a function."));
  }

  return ret_value;
} /* ecma_builtin_helper_get_to_locale_string_at_index */


/**
 * The Object.keys and Object.getOwnPropertyNames routine's common part.
 *
 * See also:
 *          ECMA-262 v5, 15.2.3.4 steps 2-5
 *          ECMA-262 v5, 15.2.3.14 steps 3-6
 *
 * @return ecma value - Array of property names.
 *         Returned value must be freed with ecma_free_value.
 */
ecma_value_t
ecma_builtin_helper_object_get_properties (ecma_object_t *obj_p, /**< object */
                                           uint32_t opts) /**< any combination of ecma_list_properties_options_t */
{
  JERRY_ASSERT (obj_p != NULL);

  ecma_value_t new_array = ecma_op_create_array_object (NULL, 0, false);
  JERRY_ASSERT (!ECMA_IS_VALUE_ERROR (new_array));
  ecma_object_t *new_array_p = ecma_get_object_from_value (new_array);

  ecma_collection_t *props_p = ecma_op_object_get_property_names (obj_p, opts);

  if (props_p->item_count == 0)
  {
    ecma_collection_destroy (props_p);
    return new_array;
  }

  JERRY_ASSERT (((ecma_extended_object_t *) new_array_p)->u.array.is_fast_mode);

  ecma_value_t *buffer_p = props_p->buffer_p;
  ecma_value_t *values_p = ecma_fast_array_extend (new_array_p, props_p->item_count);

  memcpy (values_p, buffer_p, props_p->item_count * sizeof (ecma_value_t));

  ecma_collection_free_objects (props_p);

  return new_array;
} /* ecma_builtin_helper_object_get_properties */

/**
 * Helper function to normalizing an array index
 *
 * This function clamps the given index to the [0, length] range.
 * If the index is negative, it is used as the offset from the end of the array,
 * to compute normalized index.
 * If the index is greater than the length of the array, the normalized index will be the length of the array.
 * If is_last_index_of is true, then we use the method in ECMA-262 v6, 22.2.3.16 to compute the normalized index.
 * See also:
 *          ECMA-262 v5, 15.4.4.10 steps 5-6, 7 (part 2) and 8
 *          ECMA-262 v5, 15.4.4.12 steps 5-6
 *          ECMA-262 v5, 15.4.4.14 steps 5
 *          ECMA-262 v5, 15.5.4.13 steps 4, 5 (part 2) and 6-7
 *
 * Used by:
 *         - The Array.prototype.slice routine.
 *         - The Array.prototype.splice routine.
 *         - The Array.prototype.indexOf routine.
 *         - The String.prototype.slice routine.
 *         - The TypedArray.prototype.indexOf routine.
 *         - The TypedArray.prototype.lastIndexOf routine
 *
 * @return uint32_t - the normalized value of the index
 */
uint32_t
ecma_builtin_helper_array_index_normalize (ecma_number_t index, /**< index */
                                           uint32_t length, /**< array's length */
                                           bool is_last_index_of) /**< true - normalize for lastIndexOf method*/
{
  uint32_t norm_index;

  if (!ecma_number_is_nan (index))
  {

    if (ecma_number_is_zero (index))
    {
      norm_index = 0;
    }
    else if (ecma_number_is_infinity (index))
    {
      if (is_last_index_of)
      {
        norm_index = ecma_number_is_negative (index) ? (uint32_t) -1 : length - 1;
      }
      else
      {
        norm_index = ecma_number_is_negative (index) ? 0 : length;
      }
    }
    else
    {
      if (ecma_number_is_negative (index))
      {
        ecma_number_t index_neg = -index;

        if (is_last_index_of)
        {
          norm_index = length - ecma_number_to_uint32 (index_neg);
        }
        else
        {
          if (index_neg > length)
          {
            norm_index = 0;
          }
          else
          {
            norm_index = length - ecma_number_to_uint32 (index_neg);
          }
        }
      }
      else
      {
        if (index > length)
        {
          norm_index = is_last_index_of ? length - 1 : length;
        }
        else
        {
          norm_index = ecma_number_to_uint32 (index);
        }
      }
    }
  }
  else
  {
    norm_index = 0;
  }

  return norm_index;
} /* ecma_builtin_helper_array_index_normalize */

/**
 * Helper function for concatenating an ecma_value_t to an Array.
 *
 * See also:
 *          ECMA-262 v5, 15.4.4.4 steps 5.b - 5.c
 *
 * Used by:
 *         - The Array.prototype.concat routine.
 *
 * @return ecma value
 *         Returned value must be freed with ecma_free_value.
 */
ecma_value_t
ecma_builtin_helper_array_concat_value (ecma_object_t *obj_p, /**< array */
                                        uint32_t *length_p, /**< [in,out] array's length */
                                        ecma_value_t value) /**< value to concat */
{
  ecma_value_t ret_value = ECMA_VALUE_EMPTY;

  /* 5.b */
  if (ecma_is_value_object (value)
      && (ecma_object_get_class_name (ecma_get_object_from_value (value)) == LIT_MAGIC_STRING_ARRAY_UL))
  {
    /* 5.b.ii */
    ECMA_TRY_CATCH (arg_len_value,
                    ecma_op_object_get_by_magic_id (ecma_get_object_from_value (value),
                                                    LIT_MAGIC_STRING_LENGTH),
                    ret_value);
    ECMA_OP_TO_NUMBER_TRY_CATCH (arg_len_number, arg_len_value, ret_value);

    uint32_t arg_len = ecma_number_to_uint32 (arg_len_number);

    /* 5.b.iii */
    for (uint32_t array_index = 0;
         array_index < arg_len && ecma_is_value_empty (ret_value);
         array_index++)
    {
      ecma_string_t *array_index_string_p = ecma_new_ecma_string_from_uint32 (array_index);

      /* 5.b.iii.2 */
      ECMA_TRY_CATCH (get_value,
                      ecma_op_object_find (ecma_get_object_from_value (value),
                                           array_index_string_p),
                      ret_value);

      if (ecma_is_value_found (get_value))
      {
        /* 5.b.iii.3.a */
        ecma_string_t *new_array_index_string_p = ecma_new_ecma_string_from_uint32 (*length_p + array_index);

        /* 5.b.iii.3.b */
        /* This will always be a simple value since 'is_throw' is false, so no need to free. */
        ecma_value_t put_comp = ecma_builtin_helper_def_prop (obj_p,
                                                              new_array_index_string_p,
                                                              get_value,
                                                              ECMA_PROPERTY_CONFIGURABLE_ENUMERABLE_WRITABLE);

        JERRY_ASSERT (ecma_is_value_true (put_comp));
        ecma_deref_ecma_string (new_array_index_string_p);
      }

      ECMA_FINALIZE (get_value);

      ecma_deref_ecma_string (array_index_string_p);
    }

    *length_p += arg_len;

    ECMA_OP_TO_NUMBER_FINALIZE (arg_len_number);
    ECMA_FINALIZE (arg_len_value);
  }
  else
  {
    ecma_string_t *new_array_index_string_p = ecma_new_ecma_string_from_uint32 ((*length_p)++);

    /* 5.c.i */
    /* This will always be a simple value since 'is_throw' is false, so no need to free. */
    ecma_value_t put_comp = ecma_builtin_helper_def_prop (obj_p,
                                                          new_array_index_string_p,
                                                          value,
                                                          ECMA_PROPERTY_CONFIGURABLE_ENUMERABLE_WRITABLE);
    JERRY_ASSERT (ecma_is_value_true (put_comp));

    ecma_deref_ecma_string (new_array_index_string_p);
  }

  return ret_value;
} /* ecma_builtin_helper_array_concat_value */

/**
 * Helper function to normalizing a string index
 *
 * This function clamps the given index to the [0, length] range.
 * If the index is negative, 0 value is used.
 * If the index is greater than the length of the string, the normalized index will be the length of the string.
 * NaN is mapped to zero or length depending on the nan_to_zero parameter.
 *
 * See also:
 *          ECMA-262 v5, 15.5.4.15
 *
 * Used by:
 *         - The String.prototype.substring routine.
 *         - The ecma_builtin_helper_string_prototype_object_index_of helper routine.
 *
 * @return uint32_t - the normalized value of the index
 */
uint32_t
ecma_builtin_helper_string_index_normalize (ecma_number_t index, /**< index */
                                            uint32_t length, /**< string's length */
                                            bool nan_to_zero) /**< whether NaN is mapped to zero (t) or length (f) */
{
  uint32_t norm_index = 0;

  if (ecma_number_is_nan (index))
  {
    if (!nan_to_zero)
    {
      norm_index = length;
    }
  }
  else if (!ecma_number_is_negative (index))
  {
    if (ecma_number_is_infinity (index))
    {
      norm_index = length;
    }
    else
    {
      norm_index = ecma_number_to_uint32 (index);

      if (norm_index > length)
      {
        norm_index = length;
      }
    }
  }

  return norm_index;
} /* ecma_builtin_helper_string_index_normalize */

/**
 * Helper function for string indexOf, lastIndexOf, startsWith, includes, endsWith functions
 *
 * See also:
 *          ECMA-262 v5, 15.5.4.7
 *          ECMA-262 v5, 15.5.4.8
 *          ECMA-262 v6, 21.1.3.6
 *          ECMA-262 v6, 21.1.3.7
 *          ECMA-262 v6, 21.1.3.18
 *
 * Used by:
 *         - The String.prototype.indexOf routine.
 *         - The String.prototype.lastIndexOf routine.
 *         - The String.prototype.startsWith routine.
 *         - The String.prototype.includes routine.
 *         - The String.prototype.endsWith routine.
 *
 * @return ecma_value_t - Returns index (last index) or a
 *                        boolean value
 */
ecma_value_t
ecma_builtin_helper_string_prototype_object_index_of (ecma_string_t *original_str_p, /**< this argument */
                                                      ecma_value_t arg1, /**< routine's first argument */
                                                      ecma_value_t arg2, /**< routine's second argument */
                                                      ecma_string_index_of_mode_t mode) /**< routine's mode */
{
  /* 5 (indexOf) -- 6 (lastIndexOf) */
  const ecma_length_t original_len = ecma_string_get_length (original_str_p);

#if ENABLED (JERRY_ES2015_BUILTIN)
  /* 4, 6 (startsWith, includes, endsWith) */
  if (mode >= ECMA_STRING_STARTS_WITH
      && (ecma_is_value_object (arg1)
      && ecma_object_class_is (ecma_get_object_from_value (arg1), LIT_MAGIC_STRING_REGEXP_UL)))
  {
    JERRY_ASSERT (ECMA_STRING_LAST_INDEX_OF < mode && mode <= ECMA_STRING_ENDS_WITH);
    return ecma_raise_type_error (ECMA_ERR_MSG ("Search string can't be of type: RegExp"));
  }
#endif /* ENABLED (JERRY_ES2015_BUILTIN) */

  /* 7, 8 */
  ecma_string_t *search_str_p = ecma_op_to_string (arg1);

  if (JERRY_UNLIKELY (search_str_p == NULL))
  {
    return ECMA_VALUE_ERROR;
  }

  /* 4 (indexOf, lastIndexOf), 9 (startsWith, includes), 10 (endsWith) */
  ecma_number_t pos_num;
  ecma_value_t ret_value  = ecma_get_number (arg2, &pos_num);

  /* 10 (startsWith, includes), 11 (endsWith) */
  if (ECMA_IS_VALUE_ERROR (ret_value))
  {
    ecma_deref_ecma_string (search_str_p);
    return ret_value;
  }

  bool use_first_index = mode != ECMA_STRING_LAST_INDEX_OF;

  /* 4b, 6 (indexOf) - 4b, 5, 7 (lastIndexOf) */
  ecma_length_t start = ecma_builtin_helper_string_index_normalize (pos_num, original_len, use_first_index);

  ecma_number_t ret_num = ECMA_NUMBER_MINUS_ONE;

  ecma_length_t index_of = 0;

  ret_value = ECMA_VALUE_FALSE;

  switch (mode)
  {
#if ENABLED (JERRY_ES2015_BUILTIN)
    case ECMA_STRING_STARTS_WITH:
    {
      if (pos_num + start > original_len)
      {
        break;
      }

      if (ecma_builtin_helper_string_find_index (original_str_p, search_str_p, true, start, &index_of))
      {
        /* 15, 16 (startsWith) */
        ret_value = ecma_make_boolean_value (index_of == start);
      }
      break;
    }
    case ECMA_STRING_INCLUDES:
    {
      if (ecma_builtin_helper_string_find_index (original_str_p, search_str_p, true, start, &index_of))
      {
        ret_value = ECMA_VALUE_TRUE;
      }
      break;
    }
    case ECMA_STRING_ENDS_WITH:
    {
      if (start == 0)
      {
        start = original_len;
      }

      ecma_length_t search_str_len = ecma_string_get_length (search_str_p);

      if (search_str_len == 0)
      {
        ret_value = ECMA_VALUE_TRUE;
        break;
      }

      int32_t start_ends_with = (int32_t) (start - search_str_len);

      if (start_ends_with < 0)
      {
        break;
      }
      if (ecma_builtin_helper_string_find_index (original_str_p, search_str_p, true,
                                                 (ecma_length_t) start_ends_with, &index_of))
      {
        ret_value = ecma_make_boolean_value (index_of == (ecma_length_t) start_ends_with);
      }
      break;
    }
#endif /* ENABLED (JERRY_ES2015_BUILTIN) */

    case ECMA_STRING_INDEX_OF:
    case ECMA_STRING_LAST_INDEX_OF:
    default:
    {
      /* 8 (indexOf) -- 9 (lastIndexOf) */
      if (ecma_builtin_helper_string_find_index (original_str_p, search_str_p, use_first_index, start, &index_of))
      {
        ret_num = ((ecma_number_t) index_of);
      }
      ret_value = ecma_make_number_value (ret_num);
      break;
    }
  }

  ecma_deref_ecma_string (search_str_p);

  return ret_value;
} /* ecma_builtin_helper_string_prototype_object_index_of */

/**
 * Helper function for finding index of a search string
 *
 * This function clamps the given index to the [0, length] range.
 * If the index is negative, 0 value is used.
 * If the index is greater than the length of the string, the normalized index will be the length of the string.
 * NaN is mapped to zero or length depending on the nan_to_zero parameter.
 *
 * See also:
 *          ECMA-262 v5, 15.5.4.7,8,11
 *
 * Used by:
 *         - The ecma_builtin_helper_string_prototype_object_index_of helper routine.
 *         - The ecma_builtin_string_prototype_object_replace_match helper routine.
 *
 * @return bool - whether there is a match for the search string
 */
bool
ecma_builtin_helper_string_find_index (ecma_string_t *original_str_p, /**< index */
                                       ecma_string_t *search_str_p, /**< string's length */
                                       bool first_index, /**< whether search for first (t) or last (f) index */
                                       ecma_length_t start_pos, /**< start position */
                                       ecma_length_t *ret_index_p) /**< [out] position found in original string */
{
  bool match_found = false;
  const ecma_length_t original_len = ecma_string_get_length (original_str_p);
  const ecma_length_t search_len = ecma_string_get_length (search_str_p);

  if (search_len <= original_len)
  {
    if (!search_len)
    {
      match_found = true;
      *ret_index_p = first_index ? 0 : original_len;
    }
    else
    {
      /* create utf8 string from original string and advance to position */
      ECMA_STRING_TO_UTF8_STRING (original_str_p, original_str_utf8_p, original_str_size);

      ecma_length_t index = start_pos;

      const lit_utf8_byte_t *original_str_curr_p = original_str_utf8_p;
      for (ecma_length_t idx = 0; idx < index; idx++)
      {
        lit_utf8_incr (&original_str_curr_p);
      }

      /* create utf8 string from search string */
      ECMA_STRING_TO_UTF8_STRING (search_str_p, search_str_utf8_p, search_str_size);

      const lit_utf8_byte_t *search_str_curr_p = search_str_utf8_p;

      /* iterate original string and try to match at each position */
      bool searching = true;
      ecma_char_t first_char = lit_utf8_read_next (&search_str_curr_p);
      while (searching)
      {
        /* match as long as possible */
        ecma_length_t match_len = 0;
        const lit_utf8_byte_t *stored_original_str_curr_p = original_str_curr_p;

        if (match_len < search_len &&
            index + match_len < original_len &&
            lit_utf8_read_next (&original_str_curr_p) == first_char)
        {
          const lit_utf8_byte_t *nested_search_str_curr_p = search_str_curr_p;
          match_len++;

          while (match_len < search_len &&
                 index + match_len < original_len &&
                 lit_utf8_read_next (&original_str_curr_p) == lit_utf8_read_next (&nested_search_str_curr_p))
          {
            match_len++;
          }
        }

        /* check for match */
        if (match_len == search_len)
        {
          match_found = true;
          *ret_index_p = index;

          break;
        }
        else
        {
          /* inc/dec index and update iterators and search condition */
          original_str_curr_p = stored_original_str_curr_p;

          if (first_index)
          {
            if ((searching = (index <= original_len - search_len)))
            {
              lit_utf8_incr (&original_str_curr_p);
              index++;
            }
          }
          else
          {
            if ((searching = (index > 0)))
            {
              lit_utf8_decr (&original_str_curr_p);
              index--;
            }
          }
        }
      }

      ECMA_FINALIZE_UTF8_STRING (search_str_utf8_p, search_str_size);
      ECMA_FINALIZE_UTF8_STRING (original_str_utf8_p, original_str_size);
    }
  }

  return match_found;
} /* ecma_builtin_helper_string_find_index */

/**
 * Helper function for using [[DefineOwnProperty]] specialized for indexed property names
 *
 * Note: this method falls back to the general ecma_builtin_helper_def_prop
 *
 * @return ecma value
 *         Returned value must be freed with ecma_free_value.
 */
ecma_value_t
ecma_builtin_helper_def_prop_by_index (ecma_object_t *obj_p, /**< object */
                                       uint32_t index, /**< property index */
                                       ecma_value_t value, /**< value */
                                       uint32_t opts) /**< any combination of ecma_property_flag_t bits */
{
  if (JERRY_LIKELY (index <= ECMA_DIRECT_STRING_MAX_IMM))
  {
    return ecma_builtin_helper_def_prop (obj_p,
                                         ECMA_CREATE_DIRECT_UINT32_STRING (index),
                                         value,
                                         opts);
  }

  ecma_string_t *index_str_p = ecma_new_non_direct_string_from_uint32 (index);
  ecma_value_t ret_value = ecma_builtin_helper_def_prop (obj_p,
                                                         index_str_p,
                                                         value,
                                                         opts);
  ecma_deref_ecma_string (index_str_p);

  return ret_value;
} /* ecma_builtin_helper_def_prop_by_index */

/**
 * Helper function for using [[DefineOwnProperty]].
 *
 * See also:
 *          ECMA-262 v5, 8.12.9
 *          ECMA-262 v5, 15.4.5.1
 *
 * @return ecma value
 *         Returned value must be freed with ecma_free_value.
 */
ecma_value_t
ecma_builtin_helper_def_prop (ecma_object_t *obj_p, /**< object */
                              ecma_string_t *index_p, /**< index string */
                              ecma_value_t value, /**< value */
                              uint32_t opts) /**< any combination of ecma_property_flag_t bits
                                              *   with the optional ECMA_IS_THROW flag */
{
  ecma_property_descriptor_t prop_desc;

  prop_desc.flags = (uint16_t) (ECMA_NAME_DATA_PROPERTY_DESCRIPTOR_BITS | opts);

  prop_desc.value = value;

  return ecma_op_object_define_own_property (obj_p,
                                             index_p,
                                             &prop_desc);
} /* ecma_builtin_helper_def_prop */

/**
 * @}
 * @}
 */