/*
* Copyright 2014 Attila Szegedi, Daniel Dekany, Jonathan Revusky
*
* 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 freemarker.template.utility;
import java.math.BigDecimal;
import java.math.BigInteger;
/**
* Number- and math-related utilities.
*
* @since 2.3.20
*/
public class NumberUtil {
private static final BigDecimal BIG_DECIMAL_INT_MIN = BigDecimal.valueOf(Integer.MIN_VALUE);
private static final BigDecimal BIG_DECIMAL_INT_MAX = BigDecimal.valueOf(Integer.MAX_VALUE);
private static final BigInteger BIG_INTEGER_INT_MIN = BIG_DECIMAL_INT_MIN.toBigInteger();
private static final BigInteger BIG_INTEGER_INT_MAX = BIG_DECIMAL_INT_MAX.toBigInteger();
private NumberUtil() { }
public static boolean isInfinite(Number num) {
if (num instanceof Double) {
return ((Double) num).isInfinite();
} else if (num instanceof Float) {
return ((Float) num).isInfinite();
} else if (isNonFPNumberOfSupportedClass(num)) {
return false;
} else {
throw new UnsupportedNumberClassException(num.getClass());
}
}
public static boolean isNaN(Number num) {
if (num instanceof Double) {
return ((Double) num).isNaN();
} else if (num instanceof Float) {
return ((Float) num).isNaN();
} else if (isNonFPNumberOfSupportedClass(num)) {
return false;
} else {
throw new UnsupportedNumberClassException(num.getClass());
}
}
/**
* @return -1 for negative, 0 for zero, 1 for positive.
* @throws ArithmeticException if the number is NaN
*/
public static int getSignum(Number num) throws ArithmeticException {
if (num instanceof Integer) {
int n = ((Integer) num).intValue();
return n > 0 ? 1 : (n == 0 ? 0 : -1);
} else if (num instanceof BigDecimal) {
BigDecimal n = (BigDecimal) num;
return n.signum();
} else if (num instanceof Double) {
double n = ((Double) num).doubleValue();
if (n > 0) return 1;
else if (n == 0) return 0;
else if (n < 0) return -1;
else throw new ArithmeticException("The signum of " + n + " is not defined."); // NaN
} else if (num instanceof Float) {
float n = ((Float) num).floatValue();
if (n > 0) return 1;
else if (n == 0) return 0;
else if (n < 0) return -1;
else throw new ArithmeticException("The signum of " + n + " is not defined."); // NaN
} else if (num instanceof Long) {
long n = ((Long) num).longValue();
return n > 0 ? 1 : (n == 0 ? 0 : -1);
} else if (num instanceof Short) {
short n = ((Short) num).shortValue();
return n > 0 ? 1 : (n == 0 ? 0 : -1);
} else if (num instanceof Byte) {
byte n = ((Byte) num).byteValue();
return n > 0 ? 1 : (n == 0 ? 0 : -1);
} else if (num instanceof BigInteger) {
BigInteger n = (BigInteger) num;
return n.signum();
} else {
throw new UnsupportedNumberClassException(num.getClass());
}
}
/**
* Tells if a {@link BigDecimal} stores a whole number. For example, it returns {@code true} for {@code 1.0000},
* but {@code false} for {@code 1.0001}.
*
* @since 2.3.21
*/
static public boolean isIntegerBigDecimal(BigDecimal bd) {
// [Java 1.5] Try to utilize BigDecimal.toXxxExact methods
return bd.scale() <= 0 // A fast check that whole numbers usually (not always) match
|| bd.setScale(0, BigDecimal.ROUND_DOWN).compareTo(bd) == 0; // This is rather slow
// Note that `bd.signum() == 0 || bd.stripTrailingZeros().scale() <= 0` was also tried for the last
// condition, but stripTrailingZeros was slower than setScale + compareTo.
}
private static boolean isNonFPNumberOfSupportedClass(Number num) {
return num instanceof Integer || num instanceof BigDecimal || num instanceof Long
|| num instanceof Short || num instanceof Byte || num instanceof BigInteger;
}
/**
* Converts a {@link Number} to {@code int} whose mathematical value is exactly the same as of the original number.
*
* @throws ArithmeticException
* if the conversion to {@code int} is not possible without losing precision or overflow/underflow.
*
* @since 2.3.22
*/
public static int toIntExact(Number num) {
if (num instanceof Integer || num instanceof Short || num instanceof Byte) {
return num.intValue();
} else if (num instanceof Long) {
final long n = num.longValue();
final int result = (int) n;
if (n != result) {
throw newLossyConverionException(num, Integer.class);
}
return result;
} else if (num instanceof Double || num instanceof Float) {
final double n = num.doubleValue();
if (n % 1 != 0 || n < Integer.MIN_VALUE || n > Integer.MAX_VALUE) {
throw newLossyConverionException(num, Integer.class);
}
return (int) n;
} else if (num instanceof BigDecimal) {
// [Java 1.5] Use BigDecimal.toIntegerExact()
BigDecimal n = (BigDecimal) num;
if (!isIntegerBigDecimal(n)
|| n.compareTo(BIG_DECIMAL_INT_MAX) > 0 || n.compareTo(BIG_DECIMAL_INT_MIN) < 0) {
throw newLossyConverionException(num, Integer.class);
}
return n.intValue();
} else if (num instanceof BigInteger) {
BigInteger n = (BigInteger) num;
if (n.compareTo(BIG_INTEGER_INT_MAX) > 0 || n.compareTo(BIG_INTEGER_INT_MIN) < 0) {
throw newLossyConverionException(num, Integer.class);
}
return n.intValue();
} else {
throw new UnsupportedNumberClassException(num.getClass());
}
}
private static ArithmeticException newLossyConverionException(Number fromValue, Class/*<Number>*/ toType) {
return new ArithmeticException(
"Can't convert " + fromValue + " to type " + ClassUtil.getShortClassName(toType) + " without loss.");
}
}