v8/test/mjsunit/string-external-cached.js

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// Flags: --expose-externalize-string --expose-gc
// Test data pointer caching of external strings.

function test() {
  // Test string.charAt.
  var charat_str = new Array(5);
  charat_str[0] = "0123456789ABCDEF0123456789ABCDEF\
0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF\
0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF\
0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF\
0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF0123456789ABCDEF";
  charat_str[1] = "0123456789ABCDEF";
  for (var i = 0; i < 6; i++) charat_str[1] += charat_str[1];
  try {  // String can only be externalized once
    externalizeString(charat_str[0], false);
    externalizeString(charat_str[1], true);
  } catch (ex) { }
  charat_str[2] = charat_str[0].slice(0, -1);
  charat_str[3] = charat_str[1].slice(0, -1);
  charat_str[4] = charat_str[0] + charat_str[0];

  for (var i = 0; i < 5; i++) {
    assertEquals('B', charat_str[i].charAt(6*16 + 11));
    assertEquals('C', charat_str[i].charAt(6*16 + 12));
    assertEquals('A', charat_str[i].charAt(3*16 + 10));
    assertEquals('B', charat_str[i].charAt(3*16 + 11));
  }

  charat_short = "01234";
  try {  // String can only be externalized once
    externalizeString(charat_short, true);
  } catch (ex) { }
  assertEquals("1", charat_short.charAt(1));

  // Test regexp and short substring.
  var re = /(A|B)/;
  var rere = /(T.{1,2}B)/;
  var ascii = "ABCDEFGHIJKLMNOPQRST";
  var twobyte = "_ABCDEFGHIJKLMNOPQRST";
  try {
    externalizeString(ascii, false);
    externalizeString(twobyte, true);
  } catch (ex) { }
  assertTrue(isOneByteString(ascii));
  assertFalse(isOneByteString(twobyte));
  var ascii_slice = ascii.slice(1,-1);
  var twobyte_slice = twobyte.slice(2,-1);
  var ascii_cons = ascii + ascii;
  var twobyte_cons = twobyte + twobyte;
  for (var i = 0; i < 2; i++) {
    assertEquals(["A", "A"], re.exec(ascii));
    assertEquals(["B", "B"], re.exec(ascii_slice));
    assertEquals(["TAB", "TAB"], rere.exec(ascii_cons));
    assertEquals(["A", "A"], re.exec(twobyte));
    assertEquals(["B", "B"], re.exec(twobyte_slice));
    assertEquals(["T_AB", "T_AB"], rere.exec(twobyte_cons));
    assertEquals("DEFG", ascii_slice.substr(2, 4));
    assertEquals("DEFG", twobyte_slice.substr(2, 4));
    assertEquals("DEFG", ascii_cons.substr(3, 4));
    assertEquals("DEFG", twobyte_cons.substr(4, 4));
  }

  // Test adding external strings
  var short_ascii = "E=";
  var long_ascii = "MCsquared";
  var short_twobyte = "E\u1234";
  var long_twobyte = "MCsquare\u1234";
  try {  // String can only be externalized once
    externalizeString(short_ascii, false);
    externalizeString(long_ascii, false);
    externalizeString(short_twobyte, true);
    externalizeString(long_twobyte, true);
    assertTrue(isOneByteString(short_asii) && isOneByteString(long_ascii));
    assertFalse(isOneByteString(short_twobyte) || isOneByteString(long_twobyte));
  } catch (ex) { }
  assertEquals("E=MCsquared", short_ascii + long_ascii);
  assertTrue(isOneByteString(short_ascii + long_ascii));
  assertEquals("MCsquaredE=", long_ascii + short_ascii);
  assertEquals("E\u1234MCsquare\u1234", short_twobyte + long_twobyte);
  assertFalse(isOneByteString(short_twobyte + long_twobyte));
  assertEquals("E=MCsquared", "E=" + long_ascii);
  assertEquals("E\u1234MCsquared", short_twobyte + "MCsquared");
  assertEquals("E\u1234MCsquared", short_twobyte + long_ascii);
  assertFalse(isOneByteString(short_twobyte + long_ascii));
}

// Run the test many times to ensure IC-s don't break things.
for (var i = 0; i < 10; i++) {
  test();
}

// Clean up string to make Valgrind happy.
gc();
gc();