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 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-

  * vim: set ts=8 sts=4 et sw=4 tw=99:

  * This Source Code Form is subject to the terms of the Mozilla Public

  * License, v. 2.0. If a copy of the MPL was not distributed with this

  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

 #ifndef js_SliceBudget_h

 #define js_SliceBudget_h

 #include <stdint.h>

 namespace js {

 /*

  * This class records how much work has been done in a given collection slice, so that

  * we can return before pausing for too long. Some slices are allowed to run for

  * unlimited time, and others are bounded. To reduce the number of gettimeofday

  * calls, we only check the time every 1000 operations.

  */

 struct JS_PUBLIC_API(SliceBudget)

 {

     int64_t deadline; /* in microseconds */

     intptr_t counter;

     static const intptr_t CounterReset = 1000;

     static const int64_t Unlimited = 0;

     static int64_t TimeBudget(int64_t millis);

     static int64_t WorkBudget(int64_t work);

     /* Equivalent to SliceBudget(UnlimitedBudget). */

     SliceBudget();

     /* Instantiate as SliceBudget(Time/WorkBudget(n)). */

     SliceBudget(int64_t budget);

     void reset() {

         deadline = INT64_MAX;

         counter = INTPTR_MAX;

     }

     void step(intptr_t amt = 1) {

         counter -= amt;

     }

     bool checkOverBudget();

     bool isOverBudget() {

         if (counter >= 0)

             return false;

         return checkOverBudget();

     }

 };

 } // namespace js

 #endif /* js_SliceBudget_h */