/*
* Copyright 2009 Google Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.template.soy.basicfunctions;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Lists;
import com.google.template.soy.data.SoyValue;
import com.google.template.soy.data.restricted.FloatData;
import com.google.template.soy.data.restricted.IntegerData;
import com.google.template.soy.data.restricted.NumberData;
import com.google.template.soy.exprtree.Operator;
import com.google.template.soy.internal.targetexpr.TargetExpr;
import com.google.template.soy.jssrc.dsl.SoyJsPluginUtils;
import com.google.template.soy.jssrc.restricted.JsExpr;
import com.google.template.soy.jssrc.restricted.SoyJsSrcFunction;
import com.google.template.soy.pysrc.restricted.PyExpr;
import com.google.template.soy.pysrc.restricted.SoyPySrcFunction;
import com.google.template.soy.shared.restricted.SoyJavaFunction;
import com.google.template.soy.shared.restricted.SoyPureFunction;
import java.util.List;
import java.util.Set;
import javax.inject.Inject;
import javax.inject.Singleton;
/**
* Soy function that rounds a number to a specified number of digits before or after the decimal
* point.
*
*/
@Singleton
@SoyPureFunction
public final class RoundFunction implements SoyJavaFunction, SoyJsSrcFunction, SoyPySrcFunction {
@Inject
RoundFunction() {}
@Override
public String getName() {
return "round";
}
@Override
public Set<Integer> getValidArgsSizes() {
return ImmutableSet.of(1, 2);
}
@Override
public SoyValue computeForJava(List<SoyValue> args) {
SoyValue value = args.get(0);
int numDigitsAfterPt = (args.size() == 2) ? args.get(1).integerValue() : 0 /* default */;
return round(value, numDigitsAfterPt);
}
/**
* Rounds the given value to the closest decimal point left (negative numbers) or right (positive
* numbers) of the decimal point
*/
public static NumberData round(SoyValue value, int numDigitsAfterPoint) {
// NOTE: for more accurate rounding, this should really be using BigDecimal which can do correct
// decimal arithmetic. However, for compatibility with js, that probably isn't an option.
if (numDigitsAfterPoint == 0) {
return IntegerData.forValue(round(value));
} else if (numDigitsAfterPoint > 0) {
double valueDouble = value.numberValue();
double shift = Math.pow(10, numDigitsAfterPoint);
return FloatData.forValue(Math.round(valueDouble * shift) / shift);
} else {
double valueDouble = value.numberValue();
double shift = Math.pow(10, -numDigitsAfterPoint);
return IntegerData.forValue((int) (Math.round(valueDouble / shift) * shift));
}
}
/** Rounds the given value to the closest integer. */
public static long round(SoyValue value) {
if (value instanceof IntegerData) {
return value.longValue();
} else {
return Math.round(value.numberValue());
}
}
@Override
public JsExpr computeForJsSrc(List<JsExpr> args) {
JsExpr value = args.get(0);
JsExpr numDigitsAfterPt = (args.size() == 2) ? args.get(1) : null;
int numDigitsAfterPtAsInt = convertNumDigits(numDigitsAfterPt);
if (numDigitsAfterPtAsInt == 0) {
// Case 1: round() has only one argument or the second argument is 0.
return new JsExpr("Math.round(" + value.getText() + ")", Integer.MAX_VALUE);
} else if ((numDigitsAfterPtAsInt >= 0 && numDigitsAfterPtAsInt <= 12)
|| numDigitsAfterPtAsInt == Integer.MIN_VALUE) {
String shiftExprText;
if (numDigitsAfterPtAsInt >= 0 && numDigitsAfterPtAsInt <= 12) {
shiftExprText = "1" + "000000000000".substring(0, numDigitsAfterPtAsInt);
} else {
shiftExprText = "Math.pow(10, " + numDigitsAfterPt.getText() + ")";
}
JsExpr shift = new JsExpr(shiftExprText, Integer.MAX_VALUE);
JsExpr valueTimesShift =
SoyJsPluginUtils.genJsExprUsingSoySyntax(
Operator.TIMES, Lists.newArrayList(value, shift));
return new JsExpr(
"Math.round(" + valueTimesShift.getText() + ") / " + shift.getText(),
Operator.DIVIDE_BY.getPrecedence());
} else if (numDigitsAfterPtAsInt < 0 && numDigitsAfterPtAsInt >= -12) {
String shiftExprText = "1" + "000000000000".substring(0, -numDigitsAfterPtAsInt);
JsExpr shift = new JsExpr(shiftExprText, Integer.MAX_VALUE);
JsExpr valueDivideByShift =
SoyJsPluginUtils.genJsExprUsingSoySyntax(
Operator.DIVIDE_BY, Lists.newArrayList(value, shift));
return new JsExpr(
"Math.round(" + valueDivideByShift.getText() + ") * " + shift.getText(),
Operator.TIMES.getPrecedence());
} else {
throw new IllegalArgumentException(
"Second argument to round() function is "
+ numDigitsAfterPtAsInt
+ ", which is too large in magnitude.");
}
}
@Override
public PyExpr computeForPySrc(List<PyExpr> args) {
PyExpr value = args.get(0);
PyExpr precision = (args.size() == 2) ? args.get(1) : null;
int precisionAsInt = convertNumDigits(precision);
boolean isLiteral = precisionAsInt != Integer.MIN_VALUE;
if ((precisionAsInt >= -12 && precisionAsInt <= 12) || !isLiteral) {
// Python rounds ties away from 0 instead of towards infinity as JS and Java do. So to make
// the behavior consistent, we add the smallest possible float amount to break ties towards
// infinity.
String floatBreakdown = "math.frexp(" + value.getText() + ")";
String precisionValue = isLiteral ? precisionAsInt + "" : precision.getText();
StringBuilder roundedValue =
new StringBuilder("round(")
.append('(')
.append(floatBreakdown)
.append("[0]")
.append(" + sys.float_info.epsilon)*2**")
.append(floatBreakdown)
.append("[1]")
.append(", ")
.append(precisionValue)
.append(")");
// The precision is less than 1. Convert to an int to prevent extraneous decimals in display.
return new PyExpr(
"runtime.simplify_num(" + roundedValue + ", " + precisionValue + ")", Integer.MAX_VALUE);
} else {
throw new IllegalArgumentException(
"Second argument to round() function is "
+ precisionAsInt
+ ", which is too large in magnitude.");
}
}
/**
* Convert the number of digits after the point from an expression to an int.
*
* @param numDigitsAfterPt The number of digits after the point as an expression
* @return The number of digits after the point and an int.
*/
private static int convertNumDigits(TargetExpr numDigitsAfterPt) {
int numDigitsAfterPtAsInt = 0;
if (numDigitsAfterPt != null) {
try {
numDigitsAfterPtAsInt = Integer.parseInt(numDigitsAfterPt.getText());
} catch (NumberFormatException nfe) {
numDigitsAfterPtAsInt = Integer.MIN_VALUE; // indicates it's not a simple integer literal
}
}
return numDigitsAfterPtAsInt;
}
}