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run-deltablue.js
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run-deltablue.js
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// Copyright 2013 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following
// disclaimer in the documentation and/or other materials provided
// with the distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Performance.now is used in latency benchmarks, the fallback is Date.now.
var performance = performance || {};
performance.now = (function() {
return performance.now ||
performance.mozNow ||
performance.msNow ||
performance.oNow ||
performance.webkitNow ||
Date.now;
})();
// Simple framework for running the benchmark suites and
// computing a score based on the timing measurements.
// A benchmark has a name (string) and a function that will be run to
// do the performance measurement. The optional setup and tearDown
// arguments are functions that will be invoked before and after
// running the benchmark, but the running time of these functions will
// not be accounted for in the benchmark score.
function Benchmark(name, doWarmup, doDeterministic, deterministicIterations,
run, setup, tearDown, rmsResult, minIterations) {
this.name = name;
this.doWarmup = doWarmup;
this.doDeterministic = doDeterministic;
this.deterministicIterations = deterministicIterations;
this.run = run;
this.Setup = setup ? setup : function() { };
this.TearDown = tearDown ? tearDown : function() { };
this.rmsResult = rmsResult ? rmsResult : null;
this.minIterations = minIterations ? minIterations : 32;
}
// Benchmark results hold the benchmark and the measured time used to
// run the benchmark. The benchmark score is computed later once a
// full benchmark suite has run to completion. If latency is set to 0
// then there is no latency score for this benchmark.
function BenchmarkResult(benchmark, time, latency) {
this.benchmark = benchmark;
this.time = time;
this.latency = latency;
}
// Automatically convert results to numbers. Used by the geometric
// mean computation.
BenchmarkResult.prototype.valueOf = function() {
return this.time;
}
// Suites of benchmarks consist of a name and the set of benchmarks in
// addition to the reference timing that the final score will be based
// on. This way, all scores are relative to a reference run and higher
// scores implies better performance.
function BenchmarkSuite(name, reference, benchmarks) {
this.name = name;
this.reference = reference;
this.benchmarks = benchmarks;
BenchmarkSuite.suites.push(this);
}
// Keep track of all declared benchmark suites.
BenchmarkSuite.suites = [];
// Scores are not comparable across versions. Bump the version if
// you're making changes that will affect that scores, e.g. if you add
// a new benchmark or change an existing one.
BenchmarkSuite.version = '9';
// Defines global benchsuite running mode that overrides benchmark suite
// behavior. Intended to be set by the benchmark driver. Undefined
// values here allow a benchmark to define behaviour itself.
BenchmarkSuite.config = {
doWarmup: undefined,
doDeterministic: undefined
};
// Override the alert function to throw an exception instead.
var alert = function(s) {
throw "Alert called with argument: " + s;
};
// To make the benchmark results predictable, we replace Math.random
// with a 100% deterministic alternative.
BenchmarkSuite.ResetRNG = function() {
Math.random = (function() {
var seed = 49734321;
return function() {
// Robert Jenkins' 32 bit integer hash function.
seed = ((seed + 0x7ed55d16) + (seed << 12)) & 0xffffffff;
seed = ((seed ^ 0xc761c23c) ^ (seed >>> 19)) & 0xffffffff;
seed = ((seed + 0x165667b1) + (seed << 5)) & 0xffffffff;
seed = ((seed + 0xd3a2646c) ^ (seed << 9)) & 0xffffffff;
seed = ((seed + 0xfd7046c5) + (seed << 3)) & 0xffffffff;
seed = ((seed ^ 0xb55a4f09) ^ (seed >>> 16)) & 0xffffffff;
return (seed & 0xfffffff) / 0x10000000;
};
})();
}
// Runs all registered benchmark suites and optionally yields between
// each individual benchmark to avoid running for too long in the
// context of browsers. Once done, the final score is reported to the
// runner.
BenchmarkSuite.RunSuites = function(runner, skipBenchmarks) {
skipBenchmarks = typeof skipBenchmarks === 'undefined' ? [] : skipBenchmarks;
var continuation = null;
var suites = BenchmarkSuite.suites;
var length = suites.length;
BenchmarkSuite.scores = [];
var index = 0;
function RunStep() {
while (continuation || index < length) {
if (continuation) {
continuation = continuation();
} else {
var suite = suites[index++];
if (runner.NotifyStart) runner.NotifyStart(suite.name);
if (skipBenchmarks.indexOf(suite.name) > -1) {
suite.NotifySkipped(runner);
} else {
continuation = suite.RunStep(runner);
}
}
if (continuation && typeof window != 'undefined' && window.setTimeout) {
window.setTimeout(RunStep, 25);
return;
}
}
// show final result
if (runner.NotifyScore) {
var score = BenchmarkSuite.GeometricMean(BenchmarkSuite.scores);
var formatted = BenchmarkSuite.FormatScore(100 * score);
runner.NotifyScore(formatted);
}
}
RunStep();
}
// Counts the total number of registered benchmarks. Useful for
// showing progress as a percentage.
BenchmarkSuite.CountBenchmarks = function() {
var result = 0;
var suites = BenchmarkSuite.suites;
for (var i = 0; i < suites.length; i++) {
result += suites[i].benchmarks.length;
}
return result;
}
// Computes the geometric mean of a set of numbers.
BenchmarkSuite.GeometricMean = function(numbers) {
var log = 0;
for (var i = 0; i < numbers.length; i++) {
log += Math.log(numbers[i]);
}
return Math.pow(Math.E, log / numbers.length);
}
// Computes the geometric mean of a set of throughput time measurements.
BenchmarkSuite.GeometricMeanTime = function(measurements) {
var log = 0;
for (var i = 0; i < measurements.length; i++) {
log += Math.log(measurements[i].time);
}
return Math.pow(Math.E, log / measurements.length);
}
// Computes the geometric mean of a set of rms measurements.
BenchmarkSuite.GeometricMeanLatency = function(measurements) {
var log = 0;
var hasLatencyResult = false;
for (var i = 0; i < measurements.length; i++) {
if (measurements[i].latency != 0) {
log += Math.log(measurements[i].latency);
hasLatencyResult = true;
}
}
if (hasLatencyResult) {
return Math.pow(Math.E, log / measurements.length);
} else {
return 0;
}
}
// Converts a score value to a string with at least three significant
// digits.
BenchmarkSuite.FormatScore = function(value) {
if (value > 100) {
return value.toFixed(0);
} else {
return value.toPrecision(3);
}
}
// Notifies the runner that we're done running a single benchmark in
// the benchmark suite. This can be useful to report progress.
BenchmarkSuite.prototype.NotifyStep = function(result) {
this.results.push(result);
if (this.runner.NotifyStep) this.runner.NotifyStep(result.benchmark.name);
}
// Notifies the runner that we're done with running a suite and that
// we have a result which can be reported to the user if needed.
BenchmarkSuite.prototype.NotifyResult = function() {
var mean = BenchmarkSuite.GeometricMeanTime(this.results);
var score = this.reference[0] / mean;
BenchmarkSuite.scores.push(score);
if (this.runner.NotifyResult) {
var formatted = BenchmarkSuite.FormatScore(100 * score);
this.runner.NotifyResult(this.name, formatted);
}
if (this.reference.length == 2) {
var meanLatency = BenchmarkSuite.GeometricMeanLatency(this.results);
if (meanLatency != 0) {
var scoreLatency = this.reference[1] / meanLatency;
BenchmarkSuite.scores.push(scoreLatency);
if (this.runner.NotifyResult) {
var formattedLatency = BenchmarkSuite.FormatScore(100 * scoreLatency)
this.runner.NotifyResult(this.name + "Latency", formattedLatency);
}
}
}
}
BenchmarkSuite.prototype.NotifySkipped = function(runner) {
BenchmarkSuite.scores.push(1); // push default reference score.
if (runner.NotifyResult) {
runner.NotifyResult(this.name, "Skipped");
}
}
// Notifies the runner that running a benchmark resulted in an error.
BenchmarkSuite.prototype.NotifyError = function(error) {
if (this.runner.NotifyError) {
this.runner.NotifyError(this.name, error);
}
if (this.runner.NotifyStep) {
this.runner.NotifyStep(this.name);
}
}
// Runs a single benchmark for at least a second and computes the
// average time it takes to run a single iteration.
BenchmarkSuite.prototype.RunSingleBenchmark = function(benchmark, data) {
var config = BenchmarkSuite.config;
var doWarmup = config.doWarmup !== undefined
? config.doWarmup
: benchmark.doWarmup;
var doDeterministic = config.doDeterministic !== undefined
? config.doDeterministic
: benchmark.doDeterministic;
function Measure(data) {
var elapsed = 0;
var start = new Date();
// Run either for 1 second or for the number of iterations specified
// by minIterations, depending on the config flag doDeterministic.
for (var i = 0; (doDeterministic ?
i<benchmark.deterministicIterations : elapsed < 1000); i++) {
benchmark.run();
elapsed = new Date() - start;
}
if (data != null) {
data.runs += i;
data.elapsed += elapsed;
}
}
// Sets up data in order to skip or not the warmup phase.
if (!doWarmup && data == null) {
data = { runs: 0, elapsed: 0 };
}
if (data == null) {
Measure(null);
return { runs: 0, elapsed: 0 };
} else {
Measure(data);
// If we've run too few iterations, we continue for another second.
if (data.runs < benchmark.minIterations) return data;
var usec = (data.elapsed * 1000) / data.runs;
var rms = (benchmark.rmsResult != null) ? benchmark.rmsResult() : 0;
this.NotifyStep(new BenchmarkResult(benchmark, usec, rms));
return null;
}
}
// This function starts running a suite, but stops between each
// individual benchmark in the suite and returns a continuation
// function which can be invoked to run the next benchmark. Once the
// last benchmark has been executed, null is returned.
BenchmarkSuite.prototype.RunStep = function(runner) {
BenchmarkSuite.ResetRNG();
this.results = [];
this.runner = runner;
var length = this.benchmarks.length;
var index = 0;
var suite = this;
var data;
// Run the setup, the actual benchmark, and the tear down in three
// separate steps to allow the framework to yield between any of the
// steps.
function RunNextSetup() {
if (index < length) {
try {
suite.benchmarks[index].Setup();
} catch (e) {
suite.NotifyError(e);
return null;
}
return RunNextBenchmark;
}
suite.NotifyResult();
return null;
}
function RunNextBenchmark() {
try {
data = suite.RunSingleBenchmark(suite.benchmarks[index], data);
} catch (e) {
suite.NotifyError(e);
return null;
}
// If data is null, we're done with this benchmark.
return (data == null) ? RunNextTearDown : RunNextBenchmark();
}
function RunNextTearDown() {
try {
suite.benchmarks[index++].TearDown();
} catch (e) {
suite.NotifyError(e);
return null;
}
return RunNextSetup;
}
// Start out running the setup.
return RunNextSetup();
}
// Copyright 2008 the V8 project authors. All rights reserved.
// Copyright 1996 John Maloney and Mario Wolczko.
// This program is free software; you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation; either version 2 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
// This implementation of the DeltaBlue benchmark is derived
// from the Smalltalk implementation by John Maloney and Mario
// Wolczko. Some parts have been translated directly, whereas
// others have been modified more aggresively to make it feel
// more like a JavaScript program.
var DeltaBlue = new BenchmarkSuite('DeltaBlue', [66118], [
new Benchmark('DeltaBlue', true, false, 4400, deltaBlue)
]);
/**
* A JavaScript implementation of the DeltaBlue constraint-solving
* algorithm, as described in:
*
* "The DeltaBlue Algorithm: An Incremental Constraint Hierarchy Solver"
* Bjorn N. Freeman-Benson and John Maloney
* January 1990 Communications of the ACM,
* also available as University of Washington TR 89-08-06.
*
* Beware: this benchmark is written in a grotesque style where
* the constraint model is built by side-effects from constructors.
* I've kept it this way to avoid deviating too much from the original
* implementation.
*/
/* --- O b j e c t M o d e l --- */
Object.defineProperty(Object.prototype, "inheritsFrom", {
value: function (shuper) {
function Inheriter() { }
Inheriter.prototype = shuper.prototype;
this.prototype = new Inheriter();
this.superConstructor = shuper;
}
});
function OrderedCollection() {
this.elms = new Array();
}
OrderedCollection.prototype.add = function (elm) {
this.elms.push(elm);
}
OrderedCollection.prototype.at = function (index) {
return this.elms[index];
}
OrderedCollection.prototype.size = function () {
return this.elms.length;
}
OrderedCollection.prototype.removeFirst = function () {
return this.elms.pop();
}
OrderedCollection.prototype.remove = function (elm) {
var index = 0, skipped = 0;
for (var i = 0; i < this.elms.length; i++) {
var value = this.elms[i];
if (value != elm) {
this.elms[index] = value;
index++;
} else {
skipped++;
}
}
for (var i = 0; i < skipped; i++)
this.elms.pop();
}
/* --- *
* S t r e n g t h
* --- */
/**
* Strengths are used to measure the relative importance of constraints.
* New strengths may be inserted in the strength hierarchy without
* disrupting current constraints. Strengths cannot be created outside
* this class, so pointer comparison can be used for value comparison.
*/
function Strength(strengthValue, name) {
this.strengthValue = strengthValue;
this.name = name;
}
Strength.stronger = function (s1, s2) {
return s1.strengthValue < s2.strengthValue;
}
Strength.weaker = function (s1, s2) {
return s1.strengthValue > s2.strengthValue;
}
Strength.weakestOf = function (s1, s2) {
return this.weaker(s1, s2) ? s1 : s2;
}
Strength.strongest = function (s1, s2) {
return this.stronger(s1, s2) ? s1 : s2;
}
Strength.prototype.nextWeaker = function () {
switch (this.strengthValue) {
case 0: return Strength.WEAKEST;
case 1: return Strength.WEAK_DEFAULT;
case 2: return Strength.NORMAL;
case 3: return Strength.STRONG_DEFAULT;
case 4: return Strength.PREFERRED;
case 5: return Strength.REQUIRED;
}
}
// Strength constants.
Strength.REQUIRED = new Strength(0, "required");
Strength.STONG_PREFERRED = new Strength(1, "strongPreferred");
Strength.PREFERRED = new Strength(2, "preferred");
Strength.STRONG_DEFAULT = new Strength(3, "strongDefault");
Strength.NORMAL = new Strength(4, "normal");
Strength.WEAK_DEFAULT = new Strength(5, "weakDefault");
Strength.WEAKEST = new Strength(6, "weakest");
/* --- *
* C o n s t r a i n t
* --- */
/**
* An abstract class representing a system-maintainable relationship
* (or "constraint") between a set of variables. A constraint supplies
* a strength instance variable; concrete subclasses provide a means
* of storing the constrained variables and other information required
* to represent a constraint.
*/
function Constraint(strength) {
this.strength = strength;
}
/**
* Activate this constraint and attempt to satisfy it.
*/
Constraint.prototype.addConstraint = function () {
this.addToGraph();
planner.incrementalAdd(this);
}
/**
* Attempt to find a way to enforce this constraint. If successful,
* record the solution, perhaps modifying the current dataflow
* graph. Answer the constraint that this constraint overrides, if
* there is one, or nil, if there isn't.
* Assume: I am not already satisfied.
*/
Constraint.prototype.satisfy = function (mark) {
this.chooseMethod(mark);
if (!this.isSatisfied()) {
if (this.strength == Strength.REQUIRED)
alert("Could not satisfy a required constraint!");
return null;
}
this.markInputs(mark);
var out = this.output();
var overridden = out.determinedBy;
if (overridden != null) overridden.markUnsatisfied();
out.determinedBy = this;
if (!planner.addPropagate(this, mark))
alert("Cycle encountered");
out.mark = mark;
return overridden;
}
Constraint.prototype.destroyConstraint = function () {
if (this.isSatisfied()) planner.incrementalRemove(this);
else this.removeFromGraph();
}
/**
* Normal constraints are not input constraints. An input constraint
* is one that depends on external state, such as the mouse, the
* keybord, a clock, or some arbitraty piece of imperative code.
*/
Constraint.prototype.isInput = function () {
return false;
}
/* --- *
* U n a r y C o n s t r a i n t
* --- */
/**
* Abstract superclass for constraints having a single possible output
* variable.
*/
function UnaryConstraint(v, strength) {
UnaryConstraint.superConstructor.call(this, strength);
this.myOutput = v;
this.satisfied = false;
this.addConstraint();
}
UnaryConstraint.inheritsFrom(Constraint);
/**
* Adds this constraint to the constraint graph
*/
UnaryConstraint.prototype.addToGraph = function () {
this.myOutput.addConstraint(this);
this.satisfied = false;
}
/**
* Decides if this constraint can be satisfied and records that
* decision.
*/
UnaryConstraint.prototype.chooseMethod = function (mark) {
this.satisfied = (this.myOutput.mark != mark)
&& Strength.stronger(this.strength, this.myOutput.walkStrength);
}
/**
* Returns true if this constraint is satisfied in the current solution.
*/
UnaryConstraint.prototype.isSatisfied = function () {
return this.satisfied;
}
UnaryConstraint.prototype.markInputs = function (mark) {
// has no inputs
}
/**
* Returns the current output variable.
*/
UnaryConstraint.prototype.output = function () {
return this.myOutput;
}
/**
* Calculate the walkabout strength, the stay flag, and, if it is
* 'stay', the value for the current output of this constraint. Assume
* this constraint is satisfied.
*/
UnaryConstraint.prototype.recalculate = function () {
this.myOutput.walkStrength = this.strength;
this.myOutput.stay = !this.isInput();
if (this.myOutput.stay) this.execute(); // Stay optimization
}
/**
* Records that this constraint is unsatisfied
*/
UnaryConstraint.prototype.markUnsatisfied = function () {
this.satisfied = false;
}
UnaryConstraint.prototype.inputsKnown = function () {
return true;
}
UnaryConstraint.prototype.removeFromGraph = function () {
if (this.myOutput != null) this.myOutput.removeConstraint(this);
this.satisfied = false;
}
/* --- *
* S t a y C o n s t r a i n t
* --- */
/**
* Variables that should, with some level of preference, stay the same.
* Planners may exploit the fact that instances, if satisfied, will not
* change their output during plan execution. This is called "stay
* optimization".
*/
function StayConstraint(v, str) {
StayConstraint.superConstructor.call(this, v, str);
}
StayConstraint.inheritsFrom(UnaryConstraint);
StayConstraint.prototype.execute = function () {
// Stay constraints do nothing
}
/* --- *
* E d i t C o n s t r a i n t
* --- */
/**
* A unary input constraint used to mark a variable that the client
* wishes to change.
*/
function EditConstraint(v, str) {
EditConstraint.superConstructor.call(this, v, str);
}
EditConstraint.inheritsFrom(UnaryConstraint);
/**
* Edits indicate that a variable is to be changed by imperative code.
*/
EditConstraint.prototype.isInput = function () {
return true;
}
EditConstraint.prototype.execute = function () {
// Edit constraints do nothing
}
/* --- *
* B i n a r y C o n s t r a i n t
* --- */
var Direction = new Object();
Direction.NONE = 0;
Direction.FORWARD = 1;
Direction.BACKWARD = -1;
/**
* Abstract superclass for constraints having two possible output
* variables.
*/
function BinaryConstraint(var1, var2, strength) {
BinaryConstraint.superConstructor.call(this, strength);
this.v1 = var1;
this.v2 = var2;
this.direction = Direction.NONE;
this.addConstraint();
}
BinaryConstraint.inheritsFrom(Constraint);
/**
* Decides if this constraint can be satisfied and which way it
* should flow based on the relative strength of the variables related,
* and record that decision.
*/
BinaryConstraint.prototype.chooseMethod = function (mark) {
if (this.v1.mark == mark) {
this.direction = (this.v2.mark != mark && Strength.stronger(this.strength, this.v2.walkStrength))
? Direction.FORWARD
: Direction.NONE;
}
if (this.v2.mark == mark) {
this.direction = (this.v1.mark != mark && Strength.stronger(this.strength, this.v1.walkStrength))
? Direction.BACKWARD
: Direction.NONE;
}
if (Strength.weaker(this.v1.walkStrength, this.v2.walkStrength)) {
this.direction = Strength.stronger(this.strength, this.v1.walkStrength)
? Direction.BACKWARD
: Direction.NONE;
} else {
this.direction = Strength.stronger(this.strength, this.v2.walkStrength)
? Direction.FORWARD
: Direction.BACKWARD
}
}
/**
* Add this constraint to the constraint graph
*/
BinaryConstraint.prototype.addToGraph = function () {
this.v1.addConstraint(this);
this.v2.addConstraint(this);
this.direction = Direction.NONE;
}
/**
* Answer true if this constraint is satisfied in the current solution.
*/
BinaryConstraint.prototype.isSatisfied = function () {
return this.direction != Direction.NONE;
}
/**
* Mark the input variable with the given mark.
*/
BinaryConstraint.prototype.markInputs = function (mark) {
this.input().mark = mark;
}
/**
* Returns the current input variable
*/
BinaryConstraint.prototype.input = function () {
return (this.direction == Direction.FORWARD) ? this.v1 : this.v2;
}
/**
* Returns the current output variable
*/
BinaryConstraint.prototype.output = function () {
return (this.direction == Direction.FORWARD) ? this.v2 : this.v1;
}
/**
* Calculate the walkabout strength, the stay flag, and, if it is
* 'stay', the value for the current output of this
* constraint. Assume this constraint is satisfied.
*/
BinaryConstraint.prototype.recalculate = function () {
var ihn = this.input(), out = this.output();
out.walkStrength = Strength.weakestOf(this.strength, ihn.walkStrength);
out.stay = ihn.stay;
if (out.stay) this.execute();
}
/**
* Record the fact that this constraint is unsatisfied.
*/
BinaryConstraint.prototype.markUnsatisfied = function () {
this.direction = Direction.NONE;
}
BinaryConstraint.prototype.inputsKnown = function (mark) {
var i = this.input();
return i.mark == mark || i.stay || i.determinedBy == null;
}
BinaryConstraint.prototype.removeFromGraph = function () {
if (this.v1 != null) this.v1.removeConstraint(this);
if (this.v2 != null) this.v2.removeConstraint(this);
this.direction = Direction.NONE;
}
/* --- *
* S c a l e C o n s t r a i n t
* --- */
/**
* Relates two variables by the linear scaling relationship: "v2 =
* (v1 * scale) + offset". Either v1 or v2 may be changed to maintain
* this relationship but the scale factor and offset are considered
* read-only.
*/
function ScaleConstraint(src, scale, offset, dest, strength) {
this.direction = Direction.NONE;
this.scale = scale;
this.offset = offset;
ScaleConstraint.superConstructor.call(this, src, dest, strength);
}
ScaleConstraint.inheritsFrom(BinaryConstraint);
/**
* Adds this constraint to the constraint graph.
*/
ScaleConstraint.prototype.addToGraph = function () {
ScaleConstraint.superConstructor.prototype.addToGraph.call(this);
this.scale.addConstraint(this);
this.offset.addConstraint(this);
}
ScaleConstraint.prototype.removeFromGraph = function () {
ScaleConstraint.superConstructor.prototype.removeFromGraph.call(this);
if (this.scale != null) this.scale.removeConstraint(this);
if (this.offset != null) this.offset.removeConstraint(this);
}
ScaleConstraint.prototype.markInputs = function (mark) {
ScaleConstraint.superConstructor.prototype.markInputs.call(this, mark);
this.scale.mark = this.offset.mark = mark;
}
/**
* Enforce this constraint. Assume that it is satisfied.
*/
ScaleConstraint.prototype.execute = function () {
if (this.direction == Direction.FORWARD) {
this.v2.value = this.v1.value * this.scale.value + this.offset.value;
} else {
this.v1.value = (this.v2.value - this.offset.value) / this.scale.value;
}
}
/**
* Calculate the walkabout strength, the stay flag, and, if it is
* 'stay', the value for the current output of this constraint. Assume
* this constraint is satisfied.
*/
ScaleConstraint.prototype.recalculate = function () {
var ihn = this.input(), out = this.output();
out.walkStrength = Strength.weakestOf(this.strength, ihn.walkStrength);
out.stay = ihn.stay && this.scale.stay && this.offset.stay;
if (out.stay) this.execute();
}
/* --- *
* E q u a l i t y C o n s t r a i n t
* --- */
/**
* Constrains two variables to have the same value.
*/
function EqualityConstraint(var1, var2, strength) {
EqualityConstraint.superConstructor.call(this, var1, var2, strength);
}
EqualityConstraint.inheritsFrom(BinaryConstraint);
/**
* Enforce this constraint. Assume that it is satisfied.
*/
EqualityConstraint.prototype.execute = function () {
this.output().value = this.input().value;
}
/* --- *
* V a r i a b l e
* --- */
/**
* A constrained variable. In addition to its value, it maintain the
* structure of the constraint graph, the current dataflow graph, and
* various parameters of interest to the DeltaBlue incremental
* constraint solver.
**/
function Variable(name, initialValue) {
this.value = initialValue || 0;
this.constraints = new OrderedCollection();
this.determinedBy = null;
this.mark = 0;
this.walkStrength = Strength.WEAKEST;
this.stay = true;
this.name = name;
}
/**
* Add the given constraint to the set of all constraints that refer
* this variable.
*/
Variable.prototype.addConstraint = function (c) {
this.constraints.add(c);
}
/**
* Removes all traces of c from this variable.
*/
Variable.prototype.removeConstraint = function (c) {
this.constraints.remove(c);
if (this.determinedBy == c) this.determinedBy = null;
}
/* --- *
* P l a n n e r
* --- */
/**
* The DeltaBlue planner
*/
function Planner() {
this.currentMark = 0;
}
/**
* Attempt to satisfy the given constraint and, if successful,
* incrementally update the dataflow graph. Details: If satifying
* the constraint is successful, it may override a weaker constraint
* on its output. The algorithm attempts to resatisfy that
* constraint using some other method. This process is repeated
* until either a) it reaches a variable that was not previously
* determined by any constraint or b) it reaches a constraint that
* is too weak to be satisfied using any of its methods. The
* variables of constraints that have been processed are marked with
* a unique mark value so that we know where we've been. This allows
* the algorithm to avoid getting into an infinite loop even if the
* constraint graph has an inadvertent cycle.
*/
Planner.prototype.incrementalAdd = function (c) {
var mark = this.newMark();
var overridden = c.satisfy(mark);
while (overridden != null)
overridden = overridden.satisfy(mark);
}
/**
* Entry point for retracting a constraint. Remove the given
* constraint and incrementally update the dataflow graph.
* Details: Retracting the given constraint may allow some currently
* unsatisfiable downstream constraint to be satisfied. We therefore collect
* a list of unsatisfied downstream constraints and attempt to
* satisfy each one in turn. This list is traversed by constraint
* strength, strongest first, as a heuristic for avoiding
* unnecessarily adding and then overriding weak constraints.
* Assume: c is satisfied.
*/
Planner.prototype.incrementalRemove = function (c) {
var out = c.output();