v8/test/mjsunit/string-fromcharcode.js

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// Flags: --allow-natives-syntax

// Test String.fromCharCode.

// Test char codes larger than 0xffff.
var expected = "";
for (var i = 100; i < 500; i++) {
  expected += String.fromCharCode(i);
}

function testCharCodeTruncation() {
  var result = "";
  for (var i = 0x100000 + 100; i < 0x100000 + 500; i++) {
    result += String.fromCharCode(i);
  }
  assertEquals(String.fromCharCode(0xFFFF), String.fromCharCode(0xFFFFFFFF));
  return result;
};
%PrepareFunctionForOptimization(testCharCodeTruncation);
assertEquals(expected, testCharCodeTruncation());
assertEquals(expected, testCharCodeTruncation());
%OptimizeFunctionOnNextCall(testCharCodeTruncation);
assertEquals(expected, testCharCodeTruncation());

// Test various receivers and arguments passed to String.fromCharCode.

Object.prototype.fromCharCode = function(x) {
  return this;
};

var fcc = String.fromCharCode;
var fcc2 = fcc;

function constFun(x) {
  return function(y) {
    return x;
  };
}

function test(num) {
  assertEquals(" ", String.fromCharCode(0x20));
  assertEquals(" ", String.fromCharCode(0x20 + 0x10000));
  assertEquals(" ", String.fromCharCode(0x20 - 0x10000));
  assertEquals(" ", String.fromCharCode(0x20 + 0.5));

  assertEquals("\u1234", String.fromCharCode(0x1234));
  assertEquals("\u1234", String.fromCharCode(0x1234 + 0x10000));
  assertEquals("\u1234", String.fromCharCode(0x1234 - 0x10000));
  assertEquals("\u1234", String.fromCharCode(0x1234 + 0.5));

  assertEquals("  ", String.fromCharCode(0x20, 0x20));
  assertEquals("  ", String.fromCharCode(0x20 + 0.5, 0x20));

  assertEquals(" ", fcc(0x20));
  assertEquals(" ", fcc(0x20 + 0x10000));
  assertEquals(" ", fcc(0x20 - 0x10000));
  assertEquals(" ", fcc(0x20 + 0.5));

  assertEquals("\u1234", fcc(0x1234));
  assertEquals("\u1234", fcc(0x1234 + 0x10000));
  assertEquals("\u1234", fcc(0x1234 - 0x10000));
  assertEquals("\u1234", fcc(0x1234 + 0.5));

  assertEquals("  ", fcc(0x20, 0x20));
  assertEquals("  ", fcc(0x20 + 0.5, 0x20));

  var receiver = num < 5 ? String : num < 9 ? 'dummy' : 42;
  fcc2 = num < 5 ? fcc :
                   num < 9 ? constFun(Object('dummy')) : constFun(Object(42));
  var expected = num < 5 ? ' ' : num < 9 ? Object('dummy') : Object(42);
  assertEquals(expected, receiver.fromCharCode(0x20));
  assertEquals(expected, receiver.fromCharCode(0x20 - 0x10000));
  assertEquals(expected, receiver.fromCharCode(0x20 + 0.5));
  assertEquals(expected, fcc2(0x20));
  assertEquals(expected, fcc2(0x20 - 0x10000));
  assertEquals(expected, fcc2(0x20 + 0.5));
}

// Use loop to test the custom IC.
for (var i = 0; i < 10; i++) {
  test(i);
}

// Test the custom IC works correctly when the map changes.
for (var i = 0; i < 10; i++) {
  var expected = i < 5 ? ' ' : 42;
  if (i == 5)
    String.fromCharCode = function() {
      return 42;
    };
  assertEquals(expected, String.fromCharCode(0x20));
}