Faster _Smi.toString()

tests/corelib/integer_to_string_test.dart

+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import "package:expect/expect.dart";
+
+main() {
+  /// Test that converting [value] to a string gives [expect].
+  /// Also test that `-value` gives `"-"+expect`.
+  test(int value, String expect) {
+    Expect.equals(expect, value.toString());
+    Expect.equals(expect, "$value");
+    Expect.equals(expect, (new StringBuffer()..write(value)).toString());
+    if (value == 0) return;
+    expect = "-$expect";
+    value = -value;
+    Expect.equals(expect, value.toString());
+    Expect.equals(expect, "$value");
+    Expect.equals(expect, (new StringBuffer()..write(value)).toString());
+  }
+
+  // Null.
+  test(0, "0");
+  test(1, "1");
+  test(2, "2");
+  test(5, "5");
+
+  // Binary special cases.
+
+  // ~2^30.
+  test(0x3fffffff, "1073741823");
+  test(0x40000000, "1073741824");
+  test(0x40000001, "1073741825");
+  // ~2^31.
+  test(0x7fffffff, "2147483647");
+  test(0x80000000, "2147483648");
+  test(0x80000001, "2147483649");
+  // ~2^32.
+  test(0xffffffff,  "4294967295");
+  test(0x100000000, "4294967296");
+  test(0x100000001, "4294967297");
+
+  // ~2^51.
+  test(0x7ffffffffffff, "2251799813685247");
+  test(0x8000000000000, "2251799813685248");
+  test(0x8000000000001, "2251799813685249");
+  // ~2^52.
+  test(0xfffffffffffff, "4503599627370495");
+  test(0x10000000000000, "4503599627370496");
+  test(0x10000000000001, "4503599627370497");
+  // ~2^53.
+  test(0x1fffffffffffff, "9007199254740991");
+  test(0x20000000000000, "9007199254740992");
+  test(0x20000000000001, "9007199254740993");         /// 01: ok
+  // ~2^62.
+  test(0x3fffffffffffffff, "4611686018427387903");    /// 01: continued
+  test(0x4000000000000000, "4611686018427387904");    /// 01: continued
+  test(0x4000000000000001, "4611686018427387905");    /// 01: continued
+  // ~2^63.
+  test(0x7fffffffffffffff, "9223372036854775807");    /// 01: continued
+  test(0x8000000000000000, "9223372036854775808");    /// 01: continued
+  test(0x8000000000000001, "9223372036854775809");    /// 01: continued
+  // ~2^64.
+  test(0xffffffffffffffff, "18446744073709551615");   /// 01: continued
+  test(0x10000000000000000, "18446744073709551616");  /// 01: continued
+  test(0x10000000000000001, "18446744073709551617");  /// 01: continued
+  // Big bignum.
+  test(123456789012345678901234567890,                /// 01: continued
+       "123456789012345678901234567890");             /// 01: continued
+
+  // Decimal special cases.
+
+  int number = 10;
+  // Numbers 99..99, 100...00, and 100..01 up to 23 digits.
+  for (int i = 1; i < 15; i++) {  // Works in dart2js up to 10^15.
+    test(number - 1, "9" * i);
+    test(number, "1" + "0" * i);
+    test(number + 1, "1" + "0" * (i - 1) + "1");
+    number *= 10;
+  }
+  // Fails to represent exactly in dart2js.
+  for (int i = 15; i < 22; i++) {                     /// 01: continued
+    test(number - 1, "9" * i);                        /// 01: continued
+    test(number, "1" + "0" * i);                      /// 01: continued
+    test(number + 1, "1" + "0" * (i - 1) + "1");      /// 01: continued
+    number *= 10;                                     /// 01: continued
+  }                                                   /// 01: continued
+}