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8200659: Improve BigDecimal support

Browse Source 
Reviewed-by: darcy, rhalade, mschoene
This commit is contained in:
bpb
2018-08-22 15:55:04 -07:00
parent e55c4f7340
commit 4778dbcffd
5 changed files with 388 additions and 44 deletions
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14
src/java.base/share/classes/java/math/BigDecimal.java
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@@ -1,5 +1,5 @@
/*
* Copyright (c) 1996, 2017, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1996, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -31,6 +31,7 @@ package java.math;
import static java.math.BigInteger.LONG_MASK;
import java.util.Arrays;
import java.util.Objects;
/**
* Immutable, arbitrary-precision signed decimal numbers. A
@@ -424,9 +425,14 @@ public class BigDecimal extends Number implements Comparable<BigDecimal> {
* @since 1.5
*/
public BigDecimal(char[] in, int offset, int len, MathContext mc) {
// protect against huge length.
if (offset + len > in.length || offset < 0)
throw new NumberFormatException("Bad offset or len arguments for char[] input.");
// protect against huge length, negative values, and integer overflow
try {
Objects.checkFromIndexSize(offset, len, in.length);
} catch (IndexOutOfBoundsException e) {
throw new NumberFormatException
("Bad offset or len arguments for char[] input.");
}
// This is the primary string to BigDecimal constructor; all
// incoming strings end up here; it uses explicit (inline)
// parsing for speed and generates at most one intermediate

151
src/java.base/share/classes/java/math/BigInteger.java
View File

@@ -307,10 +307,8 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
public BigInteger(byte[] val, int off, int len) {
if (val.length == 0) {
throw new NumberFormatException("Zero length BigInteger");
} else if ((off < 0) || (off >= val.length) || (len < 0) ||
(len > val.length - off)) { // 0 <= off < val.length
throw new IndexOutOfBoundsException();
}
Objects.checkFromIndexSize(off, len, val.length);
if (val[off] < 0) {
mag = makePositive(val, off, len);
@@ -395,12 +393,8 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
public BigInteger(int signum, byte[] magnitude, int off, int len) {
if (signum < -1 || signum > 1) {
throw(new NumberFormatException("Invalid signum value"));
} else if ((off < 0) || (len < 0) ||
(len > 0 &&
((off >= magnitude.length) ||
(len > magnitude.length - off)))) { // 0 <= off < magnitude.length
throw new IndexOutOfBoundsException();
}
Objects.checkFromIndexSize(off, len, magnitude.length);
// stripLeadingZeroBytes() returns a zero length array if len == 0
this.mag = stripLeadingZeroBytes(magnitude, off, len);
@@ -1239,6 +1233,14 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
private static final double LOG_TWO = Math.log(2.0);
static {
assert 0 < KARATSUBA_THRESHOLD
&& KARATSUBA_THRESHOLD < TOOM_COOK_THRESHOLD
&& TOOM_COOK_THRESHOLD < Integer.MAX_VALUE
&& 0 < KARATSUBA_SQUARE_THRESHOLD
&& KARATSUBA_SQUARE_THRESHOLD < TOOM_COOK_SQUARE_THRESHOLD
&& TOOM_COOK_SQUARE_THRESHOLD < Integer.MAX_VALUE :
"Algorithm thresholds are inconsistent";
for (int i = 1; i <= MAX_CONSTANT; i++) {
int[] magnitude = new int[1];
magnitude[0] = i;
@@ -1562,6 +1564,18 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
* @return {@code this * val}
*/
public BigInteger multiply(BigInteger val) {
return multiply(val, false);
}
/**
* Returns a BigInteger whose value is {@code (this * val)}. If
* the invocation is recursive certain overflow checks are skipped.
*
* @param val value to be multiplied by this BigInteger.
* @param isRecursion whether this is a recursive invocation
* @return {@code this * val}
*/
private BigInteger multiply(BigInteger val, boolean isRecursion) {
if (val.signum == 0 || signum == 0)
return ZERO;
@@ -1589,6 +1603,63 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
if ((xlen < TOOM_COOK_THRESHOLD) && (ylen < TOOM_COOK_THRESHOLD)) {
return multiplyKaratsuba(this, val);
} else {
//
// In "Hacker's Delight" section 2-13, p.33, it is explained
// that if x and y are unsigned 32-bit quantities and m and n
// are their respective numbers of leading zeros within 32 bits,
// then the number of leading zeros within their product as a
// 64-bit unsigned quantity is either m + n or m + n + 1. If
// their product is not to overflow, it cannot exceed 32 bits,
// and so the number of leading zeros of the product within 64
// bits must be at least 32, i.e., the leftmost set bit is at
// zero-relative position 31 or less.
//
// From the above there are three cases:
//
// m + n leftmost set bit condition
// ----- ---------------- ---------
// >= 32 x <= 64 - 32 = 32 no overflow
// == 31 x >= 64 - 32 = 32 possible overflow
// <= 30 x >= 64 - 31 = 33 definite overflow
//
// The "possible overflow" condition cannot be detected by
// examning data lengths alone and requires further calculation.
//
// By analogy, if 'this' and 'val' have m and n as their
// respective numbers of leading zeros within 32*MAX_MAG_LENGTH
// bits, then:
//
// m + n >= 32*MAX_MAG_LENGTH no overflow
// m + n == 32*MAX_MAG_LENGTH - 1 possible overflow
// m + n <= 32*MAX_MAG_LENGTH - 2 definite overflow
//
// Note however that if the number of ints in the result
// were to be MAX_MAG_LENGTH and mag[0] < 0, then there would
// be overflow. As a result the leftmost bit (of mag[0]) cannot
// be used and the constraints must be adjusted by one bit to:
//
// m + n > 32*MAX_MAG_LENGTH no overflow
// m + n == 32*MAX_MAG_LENGTH possible overflow
// m + n < 32*MAX_MAG_LENGTH definite overflow
//
// The foregoing leading zero-based discussion is for clarity
// only. The actual calculations use the estimated bit length
// of the product as this is more natural to the internal
// array representation of the magnitude which has no leading
// zero elements.
//
if (!isRecursion) {
// The bitLength() instance method is not used here as we
// are only considering the magnitudes as non-negative. The
// Toom-Cook multiplication algorithm determines the sign
// at its end from the two signum values.
if (bitLength(mag, mag.length) +
bitLength(val.mag, val.mag.length) >
32L*MAX_MAG_LENGTH) {
reportOverflow();
}
}
return multiplyToomCook3(this, val);
}
}
@@ -1674,7 +1745,7 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
int ystart = ylen - 1;
if (z == null || z.length < (xlen+ ylen))
z = new int[xlen+ylen];
z = new int[xlen+ylen];
long carry = 0;
for (int j=ystart, k=ystart+1+xstart; j >= 0; j--, k--) {
@@ -1808,16 +1879,16 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
BigInteger v0, v1, v2, vm1, vinf, t1, t2, tm1, da1, db1;
v0 = a0.multiply(b0);
v0 = a0.multiply(b0, true);
da1 = a2.add(a0);
db1 = b2.add(b0);
vm1 = da1.subtract(a1).multiply(db1.subtract(b1));
vm1 = da1.subtract(a1).multiply(db1.subtract(b1), true);
da1 = da1.add(a1);
db1 = db1.add(b1);
v1 = da1.multiply(db1);
v1 = da1.multiply(db1, true);
v2 = da1.add(a2).shiftLeft(1).subtract(a0).multiply(
db1.add(b2).shiftLeft(1).subtract(b0));
vinf = a2.multiply(b2);
db1.add(b2).shiftLeft(1).subtract(b0), true);
vinf = a2.multiply(b2, true);
// The algorithm requires two divisions by 2 and one by 3.
// All divisions are known to be exact, that is, they do not produce
@@ -1983,6 +2054,17 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
* @return {@code this<sup>2</sup>}
*/
private BigInteger square() {
return square(false);
}
/**
* Returns a BigInteger whose value is {@code (this<sup>2</sup>)}. If
* the invocation is recursive certain overflow checks are skipped.
*
* @param isRecursion whether this is a recursive invocation
* @return {@code this<sup>2</sup>}
*/
private BigInteger square(boolean isRecursion) {
if (signum == 0) {
return ZERO;
}
@@ -1995,6 +2077,15 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
if (len < TOOM_COOK_SQUARE_THRESHOLD) {
return squareKaratsuba();
} else {
//
// For a discussion of overflow detection see multiply()
//
if (!isRecursion) {
if (bitLength(mag, mag.length) > 16L*MAX_MAG_LENGTH) {
reportOverflow();
}
}
return squareToomCook3();
}
}
@@ -2146,13 +2237,13 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
a0 = getToomSlice(k, r, 2, len);
BigInteger v0, v1, v2, vm1, vinf, t1, t2, tm1, da1;
v0 = a0.square();
v0 = a0.square(true);
da1 = a2.add(a0);
vm1 = da1.subtract(a1).square();
vm1 = da1.subtract(a1).square(true);
da1 = da1.add(a1);
v1 = da1.square();
vinf = a2.square();
v2 = da1.add(a2).shiftLeft(1).subtract(a0).square();
v1 = da1.square(true);
vinf = a2.square(true);
v2 = da1.add(a2).shiftLeft(1).subtract(a0).square(true);
// The algorithm requires two divisions by 2 and one by 3.
// All divisions are known to be exact, that is, they do not produce
@@ -2323,10 +2414,11 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
// The remaining part can then be exponentiated faster. The
// powers of two will be multiplied back at the end.
int powersOfTwo = partToSquare.getLowestSetBit();
long bitsToShift = (long)powersOfTwo * exponent;
if (bitsToShift > Integer.MAX_VALUE) {
long bitsToShiftLong = (long)powersOfTwo * exponent;
if (bitsToShiftLong > Integer.MAX_VALUE) {
reportOverflow();
}
int bitsToShift = (int)bitsToShiftLong;
int remainingBits;
@@ -2336,9 +2428,9 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
remainingBits = partToSquare.bitLength();
if (remainingBits == 1) { // Nothing left but +/- 1?
if (signum < 0 && (exponent&1) == 1) {
return NEGATIVE_ONE.shiftLeft(powersOfTwo*exponent);
return NEGATIVE_ONE.shiftLeft(bitsToShift);
} else {
return ONE.shiftLeft(powersOfTwo*exponent);
return ONE.shiftLeft(bitsToShift);
}
}
} else {
@@ -2383,13 +2475,16 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
if (bitsToShift + scaleFactor <= 62) { // Fits in long?
return valueOf((result << bitsToShift) * newSign);
} else {
return valueOf(result*newSign).shiftLeft((int) bitsToShift);
return valueOf(result*newSign).shiftLeft(bitsToShift);
}
}
else {
} else {
return valueOf(result*newSign);
}
} else {
if ((long)bitLength() * exponent / Integer.SIZE > MAX_MAG_LENGTH) {
reportOverflow();
}
// Large number algorithm. This is basically identical to
// the algorithm above, but calls multiply() and square()
// which may use more efficient algorithms for large numbers.
@@ -2409,7 +2504,7 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
// Multiply back the (exponentiated) powers of two (quickly,
// by shifting left)
if (powersOfTwo > 0) {
answer = answer.shiftLeft(powersOfTwo*exponent);
answer = answer.shiftLeft(bitsToShift);
}
if (signum < 0 && (exponent&1) == 1) {
@@ -3584,7 +3679,7 @@ public class BigInteger extends Number implements Comparable<BigInteger> {
for (int i=1; i< len && pow2; i++)
pow2 = (mag[i] == 0);
n = (pow2 ? magBitLength -1 : magBitLength);
n = (pow2 ? magBitLength - 1 : magBitLength);
} else {
n = magBitLength;
}

27
test/jdk/java/math/BigDecimal/AddTests.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright (c) 2006, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2006, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -23,7 +23,7 @@
/*
* @test
* @bug 6362557
* @bug 6362557 8200698
* @summary Some tests of add(BigDecimal, mc)
* @author Joseph D. Darcy
*/
@@ -290,12 +290,35 @@ public class AddTests {
return failures;
}
private static int arithmeticExceptionTest() {
int failures = 0;
BigDecimal x;
try {
//
// The string representation "1e2147483647", which is equivalent
// to 10^Integer.MAX_VALUE, is used to create an augend with an
// unscaled value of 1 and a scale of -Integer.MAX_VALUE. The
// addend "1" has an unscaled value of 1 with a scale of 0. The
// addition is performed exactly and is specified to have a
// preferred scale of max(-Integer.MAX_VALUE, 0). As the scale
// of the result is 0, a value with Integer.MAX_VALUE + 1 digits
// would need to be created. Therefore the next statement is
// expected to overflow with an ArithmeticException.
//
x = new BigDecimal("1e2147483647").add(new BigDecimal(1));
failures++;
} catch (ArithmeticException ae) {
}
return failures;
}
public static void main(String argv[]) {
int failures = 0;
failures += extremaTests();
failures += roundingGradationTests();
failures += precisionConsistencyTest();
failures += arithmeticExceptionTest();
if (failures > 0) {
throw new RuntimeException("Incurred " + failures +

48
test/jdk/java/math/BigDecimal/Constructor.java
View File

@@ -1,5 +1,5 @@
/*
* Copyright (c) 1999, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
@@ -23,20 +23,48 @@
/*
* @test
* @bug 4259453
* @summary Test string constructor of BigDecimal
* @bug 4259453 8200698
* @summary Test constructors of BigDecimal
* @library ..
* @run testng Constructor
*/
import java.math.BigDecimal;
import org.testng.annotations.Test;
public class Constructor {
public static void main(String[] args) throws Exception {
boolean nfe = false;
@Test(expectedExceptions=NumberFormatException.class)
public void stringConstructor() {
BigDecimal bd = new BigDecimal("1.2e");
}
@Test(expectedExceptions=NumberFormatException.class)
public void charArrayConstructorNegativeOffset() {
BigDecimal bd = new BigDecimal(new char[5], -1, 4, null);
}
@Test(expectedExceptions=NumberFormatException.class)
public void charArrayConstructorNegativeLength() {
BigDecimal bd = new BigDecimal(new char[5], 0, -1, null);
}
@Test(expectedExceptions=NumberFormatException.class)
public void charArrayConstructorIntegerOverflow() {
try {
BigDecimal bd = new BigDecimal("1.2e");
} catch (NumberFormatException e) {
nfe = true;
BigDecimal bd = new BigDecimal(new char[5], Integer.MAX_VALUE - 5,
6, null);
} catch (NumberFormatException nfe) {
if (nfe.getCause() instanceof IndexOutOfBoundsException) {
throw new RuntimeException
("NumberFormatException should not have a cause");
} else {
throw nfe;
}
}
if (!nfe)
throw new Exception("Didn't throw NumberFormatException");
}
@Test(expectedExceptions=NumberFormatException.class)
public void charArrayConstructorIndexOutOfBounds() {
BigDecimal bd = new BigDecimal(new char[5], 1, 5, null);
}
}

192
test/jdk/java/math/BigInteger/LargeValueExceptions.java Normal file
View File

@@ -0,0 +1,192 @@
/*
* Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
*
* This code 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
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* @test
* @bug 8200698
* @summary Tests that exceptions are thrown for ops which would overflow
* @requires os.maxMemory >= 4g
* @run testng/othervm -Xmx4g LargeValueExceptions
*/
import java.math.BigInteger;
import static java.math.BigInteger.ONE;
import org.testng.annotations.Test;
//
// The intent of this test is to probe the boundaries between overflow and
// non-overflow, principally for multiplication and squaring, specifically
// the largest values which should not overflow and the smallest values which
// should. The transition values used are not necessarily at the exact
// boundaries but should be "close." Quite a few different values were used
// experimentally before settling on the ones in this test. For multiplication
// and squaring all cases are exercised: definite overflow and non-overflow
// which can be detected "up front," and "indefinite" overflow, i.e., overflow
// which cannot be detected up front so further calculations are required.
//
// Testing negative values is unnecessary. For both multiplication and squaring
// the paths lead to the Toom-Cook algorithm where the signum is used only to
// determine the sign of the result and not in the intermediate calculations.
// This is also true for exponentiation.
//
// @Test annotations with optional element "enabled" set to "false" should
// succeed when "enabled" is set to "true" but they take too to run in the
// course of the typical regression test execution scenario.
//
public class LargeValueExceptions {
// BigInteger.MAX_MAG_LENGTH
private static final int MAX_INTS = 1 << 26;
// Number of bits corresponding to MAX_INTS
private static final long MAX_BITS = (0xffffffffL & MAX_INTS) << 5L;
// Half BigInteger.MAX_MAG_LENGTH
private static final int MAX_INTS_HALF = MAX_INTS / 2;
// --- squaring ---
// Largest no overflow determined by examining data lengths alone.
@Test(enabled=false)
public void squareNoOverflow() {
BigInteger x = ONE.shiftLeft(16*MAX_INTS - 1).subtract(ONE);
BigInteger y = x.multiply(x);
}
// Smallest no overflow determined by extra calculations.
@Test(enabled=false)
public void squareIndefiniteOverflowSuccess() {
BigInteger x = ONE.shiftLeft(16*MAX_INTS - 1);
BigInteger y = x.multiply(x);
}
// Largest overflow detected by extra calculations.
@Test(expectedExceptions=ArithmeticException.class,enabled=false)
public void squareIndefiniteOverflowFailure() {
BigInteger x = ONE.shiftLeft(16*MAX_INTS).subtract(ONE);
BigInteger y = x.multiply(x);
}
// Smallest overflow detected by examining data lengths alone.
@Test(expectedExceptions=ArithmeticException.class)
public void squareDefiniteOverflow() {
BigInteger x = ONE.shiftLeft(16*MAX_INTS);
BigInteger y = x.multiply(x);
}
// --- multiplication ---
// Largest no overflow determined by examining data lengths alone.
@Test(enabled=false)
public void multiplyNoOverflow() {
final int halfMaxBits = MAX_INTS_HALF << 5;
BigInteger x = ONE.shiftLeft(halfMaxBits).subtract(ONE);
BigInteger y = ONE.shiftLeft(halfMaxBits - 1).subtract(ONE);
BigInteger z = x.multiply(y);
}
// Smallest no overflow determined by extra calculations.
@Test(enabled=false)
public void multiplyIndefiniteOverflowSuccess() {
BigInteger x = ONE.shiftLeft((int)(MAX_BITS/2) - 1);
long m = MAX_BITS - x.bitLength();
BigInteger y = ONE.shiftLeft((int)(MAX_BITS/2) - 1);
long n = MAX_BITS - y.bitLength();
if (m + n != MAX_BITS) {
throw new RuntimeException("Unexpected leading zero sum");
}
BigInteger z = x.multiply(y);
}
// Largest overflow detected by extra calculations.
@Test(expectedExceptions=ArithmeticException.class,enabled=false)
public void multiplyIndefiniteOverflowFailure() {
BigInteger x = ONE.shiftLeft((int)(MAX_BITS/2)).subtract(ONE);
long m = MAX_BITS - x.bitLength();
BigInteger y = ONE.shiftLeft((int)(MAX_BITS/2)).subtract(ONE);
long n = MAX_BITS - y.bitLength();
if (m + n != MAX_BITS) {
throw new RuntimeException("Unexpected leading zero sum");
}
BigInteger z = x.multiply(y);
}
// Smallest overflow detected by examining data lengths alone.
@Test(expectedExceptions=ArithmeticException.class)
public void multiplyDefiniteOverflow() {
// multiply by 4 as MAX_INTS_HALF refers to ints
byte[] xmag = new byte[4*MAX_INTS_HALF];
xmag[0] = (byte)0xff;
BigInteger x = new BigInteger(1, xmag);
byte[] ymag = new byte[4*MAX_INTS_HALF + 1];
ymag[0] = (byte)0xff;
BigInteger y = new BigInteger(1, ymag);
BigInteger z = x.multiply(y);
}
// --- exponentiation ---
@Test(expectedExceptions=ArithmeticException.class)
public void powOverflow() {
BigInteger.TEN.pow(Integer.MAX_VALUE);
}
@Test(expectedExceptions=ArithmeticException.class)
public void powOverflow1() {
int shift = 20;
int exponent = 1 << shift;
BigInteger x = ONE.shiftLeft((int)(MAX_BITS / exponent));
BigInteger y = x.pow(exponent);
}
@Test(expectedExceptions=ArithmeticException.class)
public void powOverflow2() {
int shift = 20;
int exponent = 1 << shift;
BigInteger x = ONE.shiftLeft((int)(MAX_BITS / exponent)).add(ONE);
BigInteger y = x.pow(exponent);
}
@Test(expectedExceptions=ArithmeticException.class,enabled=false)
public void powOverflow3() {
int shift = 20;
int exponent = 1 << shift;
BigInteger x = ONE.shiftLeft((int)(MAX_BITS / exponent)).subtract(ONE);
BigInteger y = x.pow(exponent);
}
@Test(enabled=false)
public void powOverflow4() {
int shift = 20;
int exponent = 1 << shift;
BigInteger x = ONE.shiftLeft((int)(MAX_BITS / exponent - 1)).add(ONE);
BigInteger y = x.pow(exponent);
}
}