Fix for issue 10534. Implement int.pow correctly. Note that int.pow is considerably slower than dou…

runtime/lib/integers.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.
 
 // TODO(srdjan): fix limitations.
 // - shift amount must be a Smi.
 class _IntegerImplementation {
   factory _IntegerImplementation._uninstantiable() {
     throw new UnsupportedError(
         "_IntegerImplementation can only be allocated by the VM");
@@ skipping 146 matching lines @@
     // Note that we don't need to care for -0.0 for the lower limit.
     if (this < lowerLimit) return lowerLimit;
     if (this.compareTo(upperLimit) > 0) return upperLimit;
     return this;
   }
 
   int toInt() { return this; }
   double toDouble() { return new _Double.fromInteger(this); }
 
   int pow(int exponent) {
-    double res = this.toDouble().pow(exponent);
-    if (res.isInfinite) {
-      // Use Bigint instead.
-      throw "_IntegerImplementation.pow not implemented for large integers.";
+    // Exponentiation by squaring.
+    int base = this;
+    int result = 1;
+    while (exponent != 0) {
+      if ((exponent & 1) == 1) {
+        result *= base;
+      }
+      exponent >>= 1;
+      base *= base;
     }
-    return res.toInt();
+    return result;
   }
 
   String toStringAsFixed(int fractionDigits) {
     return this.toDouble().toStringAsFixed(fractionDigits);
   }
   String toStringAsExponential([int fractionDigits]) {
     return this.toDouble().toStringAsExponential(fractionDigits);
   }
   String toStringAsPrecision(int precision) {
     return this.toDouble().toStringAsPrecision(precision);
@@ skipping 111 matching lines @@
     }
   }
   int _shlFromInt(int other) {
     throw const OutOfMemoryError();
   }
 
   int pow(int exponent) {
     throw "Bigint.pow not implemented";
   }
 }