string-iterator.js 3.03 KB
Newer Older
1 2 3 4
// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

5 6
(function() {

7
"use strict";
8

9
%CheckIsBootstrapping();
10

11 12
var GlobalObject = global.Object;
var GlobalString = global.String;
13

14
//-------------------------------------------------------------------
15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43

var stringIteratorIteratedStringSymbol =
    GLOBAL_PRIVATE("StringIterator#iteratedString");
var stringIteratorNextIndexSymbol = GLOBAL_PRIVATE("StringIterator#next");


function StringIterator() {}


// 21.1.5.1 CreateStringIterator Abstract Operation
function CreateStringIterator(string) {
  var s = TO_STRING_INLINE(string);
  var iterator = new StringIterator;
  SET_PRIVATE(iterator, stringIteratorIteratedStringSymbol, s);
  SET_PRIVATE(iterator, stringIteratorNextIndexSymbol, 0);
  return iterator;
}


// 21.1.5.2.2 %StringIteratorPrototype%[@@iterator]
function StringIteratorIterator() {
  return this;
}


// 21.1.5.2.1 %StringIteratorPrototype%.next( )
function StringIteratorNext() {
  var iterator = ToObject(this);

44
  if (!HAS_DEFINED_PRIVATE(iterator, stringIteratorNextIndexSymbol)) {
45 46
    throw MakeTypeError(kIncompatibleMethodReceiver,
                        'String Iterator.prototype.next');
47 48 49 50
  }

  var s = GET_PRIVATE(iterator, stringIteratorIteratedStringSymbol);
  if (IS_UNDEFINED(s)) {
51
    return $iteratorCreateResultObject(UNDEFINED, true);
52 53 54 55 56 57
  }

  var position = GET_PRIVATE(iterator, stringIteratorNextIndexSymbol);
  var length = TO_UINT32(s.length);

  if (position >= length) {
58 59
    SET_PRIVATE(iterator, stringIteratorIteratedStringSymbol,
                UNDEFINED);
60
    return $iteratorCreateResultObject(UNDEFINED, true);
61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76
  }

  var first = %_StringCharCodeAt(s, position);
  var resultString = %_StringCharFromCode(first);
  position++;

  if (first >= 0xD800 && first <= 0xDBFF && position < length) {
    var second = %_StringCharCodeAt(s, position);
    if (second >= 0xDC00 && second <= 0xDFFF) {
      resultString += %_StringCharFromCode(second);
      position++;
    }
  }

  SET_PRIVATE(iterator, stringIteratorNextIndexSymbol, position);

77
  return $iteratorCreateResultObject(resultString, false);
78 79 80 81 82 83 84 85
}


// 21.1.3.27 String.prototype [ @@iterator ]( )
function StringPrototypeIterator() {
  return CreateStringIterator(this);
}

86
//-------------------------------------------------------------------
87

88 89
%FunctionSetPrototype(StringIterator, new GlobalObject());
%FunctionSetInstanceClassName(StringIterator, 'String Iterator');
90

91
InstallFunctions(StringIterator.prototype, DONT_ENUM, [
92
  'next', StringIteratorNext
93
]);
94
SetFunctionName(StringIteratorIterator, symbolIterator);
95 96 97 98 99
%AddNamedProperty(StringIterator.prototype, symbolIterator,
                  StringIteratorIterator, DONT_ENUM);
%AddNamedProperty(StringIterator.prototype, symbolToStringTag,
                  "String Iterator", READ_ONLY | DONT_ENUM);

100
SetFunctionName(StringPrototypeIterator, symbolIterator);
101 102 103 104
%AddNamedProperty(GlobalString.prototype, symbolIterator,
                  StringPrototypeIterator, DONT_ENUM);

})();