8022109: Evaluate adding incrementExact, decrementExact, negateExact to java.lang.Math
Summary: Add the methods for parameter types int and long.
Reviewed-by: mduigou
Contributed-by: Brian Burkhalter <brian.burkhalter@oracle.com>
--- a/jdk/src/share/classes/java/lang/Math.java Wed Aug 14 11:42:59 2013 -0700
+++ b/jdk/src/share/classes/java/lang/Math.java Mon Aug 12 10:35:44 2013 -0700
@@ -825,7 +825,7 @@
public static int multiplyExact(int x, int y) {
long r = (long)x * (long)y;
if ((int)r != r) {
- throw new ArithmeticException("long overflow");
+ throw new ArithmeticException("integer overflow");
}
return (int)r;
}
@@ -857,6 +857,108 @@
}
/**
+ * Returns the argument incremented by one, throwing an exception if the
+ * result overflows an {@code int}.
+ *
+ * @param a the value to increment
+ * @return the result
+ * @throws ArithmeticException if the result overflows an int
+ * @since 1.8
+ */
+ public static int incrementExact(int a) {
+ if (a == Integer.MAX_VALUE) {
+ throw new ArithmeticException("integer overflow");
+ }
+
+ return a + 1;
+ }
+
+ /**
+ * Returns the argument incremented by one, throwing an exception if the
+ * result overflows a {@code long}.
+ *
+ * @param a the value to increment
+ * @return the result
+ * @throws ArithmeticException if the result overflows a long
+ * @since 1.8
+ */
+ public static long incrementExact(long a) {
+ if (a == Long.MAX_VALUE) {
+ throw new ArithmeticException("long overflow");
+ }
+
+ return a + 1L;
+ }
+
+ /**
+ * Returns the argument decremented by one, throwing an exception if the
+ * result overflows an {@code int}.
+ *
+ * @param a the value to decrement
+ * @return the result
+ * @throws ArithmeticException if the result overflows an int
+ * @since 1.8
+ */
+ public static int decrementExact(int a) {
+ if (a == Integer.MIN_VALUE) {
+ throw new ArithmeticException("integer overflow");
+ }
+
+ return a - 1;
+ }
+
+ /**
+ * Returns the argument decremented by one, throwing an exception if the
+ * result overflows a {@code long}.
+ *
+ * @param a the value to decrement
+ * @return the result
+ * @throws ArithmeticException if the result overflows a long
+ * @since 1.8
+ */
+ public static long decrementExact(long a) {
+ if (a == Long.MIN_VALUE) {
+ throw new ArithmeticException("long overflow");
+ }
+
+ return a - 1L;
+ }
+
+ /**
+ * Returns the negation of the argument, throwing an exception if the
+ * result overflows an {@code int}.
+ *
+ * @param a the value to negate
+ * @return the result
+ * @throws ArithmeticException if the result overflows an int
+ * @since 1.8
+ */
+ public static int negateExact(int a) {
+ if (a == Integer.MIN_VALUE) {
+ throw new ArithmeticException("integer overflow");
+ }
+
+ return -a;
+ }
+
+ /**
+ * Returns the negation of the argument, throwing an exception if the
+ * result overflows a {@code long}.
+ *
+ * @param a the value to negate
+ * @return the result
+ * @throws ArithmeticException if the result overflows a long
+ * @since 1.8
+ */
+ public static long negateExact(long a) {
+ if (a == Long.MIN_VALUE) {
+ throw new ArithmeticException("long overflow");
+ }
+
+ return -a;
+ }
+
+ /**
* Returns the value of the {@code long} argument;
* throwing an exception if the value overflows an {@code int}.
*
--- a/jdk/test/java/lang/Math/ExactArithTests.java Wed Aug 14 11:42:59 2013 -0700
+++ b/jdk/test/java/lang/Math/ExactArithTests.java Mon Aug 12 10:35:44 2013 -0700
@@ -132,7 +132,56 @@
fail("FAIL: int Math.multiplyExact(" + x + " * " + y + ")" + "; Unexpected exception: " + ex);
}
}
+ try {
+ // Test incrementExact
+ int inc = Math.incrementExact(x);
+ long inc2 = (long) x + 1L;
+ if ((int) inc2 != inc2) {
+ fail("FAIL: int Math.incrementExact(" + x + ") = " + inc + "; expected Arithmetic exception");
+ } else if (inc != inc2) {
+ fail("FAIL: long Math.incrementExact(" + x + ") = " + inc + "; expected: " + inc2);
+ }
+ } catch (ArithmeticException ex) {
+ long inc2 = (long) x + 1L;
+ if ((int) inc2 == inc2) {
+ fail("FAIL: int Math.incrementExact(" + x + ")" + "; Unexpected exception: " + ex);
+ }
+ }
+
+ try {
+ // Test decrementExact
+ int dec = Math.decrementExact(x);
+ long dec2 = (long) x - 1L;
+ if ((int) dec2 != dec2) {
+ fail("FAIL: int Math.decrementExact(" + x + ") = " + dec + "; expected Arithmetic exception");
+ } else if (dec != dec2) {
+ fail("FAIL: long Math.decrementExact(" + x + ") = " + dec + "; expected: " + dec2);
+ }
+ } catch (ArithmeticException ex) {
+ long dec2 = (long) x - 1L;
+ if ((int) dec2 == dec2) {
+ fail("FAIL: int Math.decrementExact(" + x + ")" + "; Unexpected exception: " + ex);
+
+ }
+ }
+
+ try {
+ // Test negateExact
+ int neg = Math.negateExact(x);
+ long neg2 = -((long)x) ;
+ if ((int) neg2 != neg2) {
+ fail("FAIL: int Math.negateExact(" + x + ") = " + neg + "; expected Arithmetic exception");
+ } else if (neg != neg2) {
+ fail("FAIL: long Math.negateExact(" + x + ") = " + neg + "; expected: " + neg2);
+ }
+ } catch (ArithmeticException ex) {
+ long neg2 = (long) x - 1L;
+ if ((int) neg2 == neg2) {
+ fail("FAIL: int Math.negateExact(" + x + ")" + "; Unexpected exception: " + ex);
+
+ }
+ }
}
/**
@@ -225,6 +274,39 @@
}
try {
+ // Test incrementExact
+ resultBig = xBig.add(BigInteger.ONE);
+ long inc = Math.incrementExact(x);
+ checkResult("long Math.incrementExact", x, 1L, inc, resultBig);
+ } catch (ArithmeticException ex) {
+ if (inLongRange(resultBig)) {
+ fail("FAIL: long Math.incrementExact(" + x + "); Unexpected exception: " + ex);
+ }
+ }
+
+ try {
+ // Test decrementExact
+ resultBig = xBig.subtract(BigInteger.ONE);
+ long dec = Math.decrementExact(x);
+ checkResult("long Math.decrementExact", x, 1L, dec, resultBig);
+ } catch (ArithmeticException ex) {
+ if (inLongRange(resultBig)) {
+ fail("FAIL: long Math.decrementExact(" + x + "); Unexpected exception: " + ex);
+ }
+ }
+
+ try {
+ // Test negateExact
+ resultBig = xBig.negate();
+ long dec = Math.negateExact(x);
+ checkResult("long Math.negateExact", x, 0L, dec, resultBig);
+ } catch (ArithmeticException ex) {
+ if (inLongRange(resultBig)) {
+ fail("FAIL: long Math.negateExact(" + x + "); Unexpected exception: " + ex);
+ }
+ }
+
+ try {
// Test toIntExact
int value = Math.toIntExact(x);
if ((long)value != x) {