Implemented Array.prototype.slice().

JerryScript-DCO-1.0-Signed-off-by: Zsolt Borbély zsborbely.u-szeged@partner.samsung.com

Author: Zsolt Borbély

jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.cpp

@@ -14,6 +14,7 @@
  */
 
 #include "ecma-alloc.h"
+#include "ecma-array-object.h"
 #include "ecma-builtins.h"
 #include "ecma-comparison.h"
 #include "ecma-conversion.h"
@@ -702,6 +703,162 @@ ecma_builtin_array_prototype_object_unshift (ecma_value_t this_arg, /**< this ar
   return ret_value;
 } /* ecma_builtin_array_prototype_object_unshift */
 
+/**
+ * The Array.prototype object's 'slice' routine
+ *
+ * See also:
+ *          ECMA-262 v5, 15.4.4.10
+ *
+ * @return completion value
+ *         Returned value must be freed with ecma_free_completion_value.
+ */
+static ecma_completion_value_t
+ecma_builtin_array_prototype_object_slice (ecma_value_t this_arg, /**< 'this' argument */
+                              ecma_value_t arg1, /**< start */
+                              ecma_value_t arg2) /**< end */
+{
+  ecma_completion_value_t ret_value = ecma_make_empty_completion_value ();
+
+  /* 1. */
+  ECMA_TRY_CATCH (obj_this,
+                  ecma_op_to_object (this_arg),
+                  ret_value);
+
+  ecma_object_t* obj_p = ecma_get_object_from_value (obj_this);
+  ecma_string_t* length_magic_string_p = ecma_get_magic_string (ECMA_MAGIC_STRING_LENGTH);
+
+  ECMA_TRY_CATCH (len_value,
+                  ecma_op_object_get (obj_p, length_magic_string_p),
+                  ret_value);
+
+  /* 3. */
+  ECMA_OP_TO_NUMBER_TRY_CATCH (len_number, len_value, ret_value);
+
+  /* 4. */
+  const uint32_t len = ecma_number_to_uint32 (len_number);
+
+  uint32_t start = 0, end = len;
+
+  /* 5. */
+  ECMA_OP_TO_NUMBER_TRY_CATCH (start_num, arg1, ret_value);
+  int32_t relative_start = ecma_number_to_int32 (start_num);
+
+  /* 6. */
+  if (relative_start < 0)
+  {
+    uint32_t start_abs = (uint32_t) -relative_start;
+
+    if (start_abs > len)
+    {
+      start = 0;
+    }
+    else
+    {
+      start = len - start_abs;
+    }
+  }
+  else
+  {
+    start = (uint32_t) relative_start;
+    if (start > len)
+    {
+      start = len;
+    }
+  }
+
+  /* 7. */
+  if (ecma_is_value_undefined (arg2))
+  {
+    end = len;
+  }
+  else
+  {
+    /* 7. part 2*/
+    ECMA_OP_TO_NUMBER_TRY_CATCH (end_num, arg2, ret_value)
+    int32_t relative_end = ecma_number_to_int32 (end_num);
+
+    if (relative_end < 0)
+    {
+      uint32_t end_abs = (uint32_t) -relative_end;
+
+      if (end_abs > len)
+      {
+        end = 0;
+      }
+      else
+      {
+        end = len - end_abs;
+      }
+    }
+    else
+    {
+      end = (uint32_t) relative_end;
+      if (end > len)
+      {
+        end = len;
+      }
+    }
+
+    ECMA_OP_TO_NUMBER_FINALIZE (end_num);
+  }
+
+  ECMA_OP_TO_NUMBER_FINALIZE (start_num);
+
+  JERRY_ASSERT (start <= len && end <= len);
+
+  ecma_completion_value_t new_array = ecma_op_create_array_object (0, 0, false);
+  ecma_object_t *new_array_p = ecma_get_object_from_completion_value (new_array);
+
+  /* 9. */
+  uint32_t n = 0;
+
+  /* 10. */
+  for (uint32_t k = start; k < end && ecma_is_completion_value_empty (ret_value); k++, n++)
+  {
+    /* 10.a */
+    ecma_string_t *curr_idx_str_p = ecma_new_ecma_string_from_uint32 (k);
+
+    /* 10.c */
+    if (ecma_op_object_get_property (obj_p, curr_idx_str_p) != NULL)
+    {
+      /* 10.c.i */
+      ECMA_TRY_CATCH (get_value, ecma_op_object_get (obj_p, curr_idx_str_p), ret_value);
+
+      ecma_string_t *to_idx_str_p = ecma_new_ecma_string_from_uint32 (n);
+      /*
+       * 10.c.ii
+       * Using [[Put]] is equivalent to using [[DefineOwnProperty]] as specified the standard,
+       * so we use [[Put]] instead for simplicity. No need for a try-catch block since it is called
+       * with is_throw = false.
+       */
+      ecma_completion_value_t put_comp_value = ecma_op_object_put (new_array_p, to_idx_str_p, get_value, false);
+      JERRY_ASSERT (ecma_is_completion_value_normal (put_comp_value));
+      ecma_free_completion_value (put_comp_value);
+      ecma_deref_ecma_string (to_idx_str_p);
+
+      ECMA_FINALIZE (get_value);
+    }
+
+    ecma_deref_ecma_string (curr_idx_str_p);
+  }
+
+  if (ecma_is_completion_value_empty (ret_value))
+  {
+    ret_value = new_array;
+  }
+  else
+  {
+    ecma_free_completion_value (new_array);
+  }
+
+  ECMA_OP_TO_NUMBER_FINALIZE (len_number);
+  ECMA_FINALIZE (len_value);
+  ecma_deref_ecma_string (length_magic_string_p);
+  ECMA_FINALIZE (obj_this);
+
+  return ret_value;
+} /* ecma_builtin_array_prototype_object_slice */
+
 /**
  * @}
  * @}

jerry-core/ecma/builtin-objects/ecma-builtin-array-prototype.inc.h

@@ -65,6 +65,7 @@ ROUTINE (ECMA_MAGIC_STRING_PUSH, ecma_builtin_array_prototype_object_push, NON_F
 ROUTINE (ECMA_MAGIC_STRING_INDEX_OF_UL, ecma_builtin_array_prototype_object_index_of, 2, 1)
 ROUTINE (ECMA_MAGIC_STRING_SHIFT, ecma_builtin_array_prototype_object_shift, 0, 0)
 ROUTINE (ECMA_MAGIC_STRING_UNSHIFT, ecma_builtin_array_prototype_object_unshift, NON_FIXED, 1)
+ROUTINE (ECMA_MAGIC_STRING_SLICE, ecma_builtin_array_prototype_object_slice, 2, 2)
 
 #undef OBJECT_ID
 #undef SIMPLE_VALUE

tests/jerry/array_prototype_slice.js

@@ -0,0 +1,70 @@
+// Copyright 2015 Samsung Electronics Co., Ltd.
+// Copyright 2015 University of Szeged.
+//
+// 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.
+
+var array = [54, undefined, "Lemon", -127];
+
+var array1 = array.slice();
+var array2 = array.slice("a", "3");
+var array3 = array.slice(-2);
+var array4 = array.slice(-12, undefined);
+var array5 = array.slice(undefined, -3);
+
+assert (array1.length == 4);
+assert (array1[0] == 54);
+assert (array1[1] == undefined);
+assert (array1[2] == "Lemon");
+assert (array1[3] == -127);
+
+assert (array2.length == 3);
+assert (array2[0] == 54);
+assert (array2[1] == undefined);
+assert (array2[2] == "Lemon");
+
+assert (array3.length == 2);
+assert (array3[0] == "Lemon");
+assert (array3[1] == -127);
+
+assert (array4.length == 4);
+assert (array4[0] == 54);
+assert (array4[1] == undefined);
+assert (array4[2] == "Lemon");
+assert (array4[3] == -127);
+
+assert (array5.length == 1);
+assert (array5[0] == 54);
+
+// Checking behavior when unable to get length
+var obj = { slice : Array.prototype.slice };
+Object.defineProperty(obj, 'length', { 'get' : function () { throw new ReferenceError ("foo"); } });
+
+try {
+	obj.slice(1, 2);
+	assert (false);
+} catch (e) {
+	assert (e.message === "foo");
+	assert (e instanceof ReferenceError);
+}
+
+// Checking behavior when unable to get element
+var obj = { length : 1, slice : Array.prototype.slice };
+Object.defineProperty(obj, '0', { 'get' : function () { throw new ReferenceError ("foo"); } });
+
+try {
+	obj.slice(0, 1);
+	assert (false);
+} catch (e) {
+	assert (e.message === "foo");
+	assert (e instanceof ReferenceError);
+}