--- old/src/share/classes/java/math/BigInteger.java Tue Mar 17 14:11:29 2009
+++ new/src/share/classes/java/math/BigInteger.java Tue Mar 17 14:11:29 2009
@@ -105,7 +105,7 @@
*
* @serial
*/
- int signum;
+ final int signum;
/**
* The magnitude of this BigInteger, in big-endian order: the
@@ -116,61 +116,62 @@
* value. Note that this implies that the BigInteger zero has a
* zero-length mag array.
*/
- int[] mag;
+ final int[] mag;
// These "redundant fields" are initialized with recognizable nonsense
// values, and cached the first time they are needed (or never, if they
// aren't needed).
- /**
- * The bitCount of this BigInteger, as returned by bitCount(), or -1
- * (either value is acceptable).
+ /**
+ * One plus the bitCount of this BigInteger. Zeros means unitialized.
*
* @serial
* @see #bitCount
+ * @deprecated Deprecated since logical value is offset from stored
+ * value and correction factor is applied in accessor method.
*/
- private int bitCount = -1;
-
+ @Deprecated
+ private int bitCount;
+
/**
- * The bitLength of this BigInteger, as returned by bitLength(), or -1
+ * One plus the bitLength of this BigInteger. Zeros means unitialized.
* (either value is acceptable).
*
* @serial
* @see #bitLength()
+ * @deprecated Deprecated since logical value is offset from stored
+ * value and correction factor is applied in accessor method.
*/
- private int bitLength = -1;
+ @Deprecated
+ private int bitLength;
/**
- * The lowest set bit of this BigInteger, as returned by getLowestSetBit(),
- * or -2 (either value is acceptable).
+ * Two plus the lowest set bit of this BigInteger, as returned by
+ * getLowestSetBit().
*
* @serial
* @see #getLowestSetBit
+ * @deprecated Deprecated since logical value is offset from stored
+ * value and correction factor is applied in accessor method.
*/
- private int lowestSetBit = -2;
+ @Deprecated
+ private int lowestSetBit;
/**
- * The index of the lowest-order byte in the magnitude of this BigInteger
- * that contains a nonzero byte, or -2 (either value is acceptable). The
- * least significant byte has int-number 0, the next byte in order of
- * increasing significance has byte-number 1, and so forth.
- *
- * @serial
- */
- private int firstNonzeroByteNum = -2;
-
- /**
- * The index of the lowest-order int in the magnitude of this BigInteger
- * that contains a nonzero int, or -2 (either value is acceptable). The
- * least significant int has int-number 0, the next int in order of
+ * Two plus the index of the lowest-order int in the magnitude of this
+ * BigInteger that contains a nonzero int, or -2 (either value is acceptable).
+ * The least significant int has int-number 0, the next int in order of
* increasing significance has int-number 1, and so forth.
+ * @deprecated Deprecated since logical value is offset from stored
+ * value and correction factor is applied in accessor method.
*/
- private int firstNonzeroIntNum = -2;
-
+ @Deprecated
+ private int firstNonzeroIntNum;
+
/**
* This mask is used to obtain the value of an int as if it were unsigned.
*/
- private final static long LONG_MASK = 0xffffffffL;
+ final static long LONG_MASK = 0xffffffffL;
//Constructors
@@ -295,7 +296,7 @@
throw new NumberFormatException("Zero length BigInteger");
// Check for at most one leading sign
- signum = 1;
+ int sign = 1;
int index1 = val.lastIndexOf('-');
int index2 = val.lastIndexOf('+');
if ((index1 + index2) <= -1) {
@@ -306,7 +307,7 @@
throw new NumberFormatException("Zero length BigInteger");
}
if (index1 == 0)
- signum = -1;
+ sign = -1;
} else
throw new NumberFormatException("Illegal embedded sign character");
@@ -318,15 +319,16 @@
signum = 0;
mag = ZERO.mag;
return;
- } else {
- numDigits = len - cursor;
}
-
+
+ numDigits = len - cursor;
+ signum = sign;
+
// Pre-allocate array of expected size. May be too large but can
// never be too small. Typically exact.
int numBits = (int)(((numDigits * bitsPerDigit[radix]) >>> 10) + 1);
- int numWords = (numBits + 31) /32;
- mag = new int[numWords];
+ int numWords = (numBits + 31) >>> 5;
+ int[] magnitude = new int[numWords];
// Process first (potentially short) digit group
int firstGroupLen = numDigits % digitsPerInt[radix];
@@ -333,8 +335,8 @@
if (firstGroupLen == 0)
firstGroupLen = digitsPerInt[radix];
String group = val.substring(cursor, cursor += firstGroupLen);
- mag[mag.length - 1] = Integer.parseInt(group, radix);
- if (mag[mag.length - 1] < 0)
+ magnitude[numWords - 1] = Integer.parseInt(group, radix);
+ if (magnitude[numWords - 1] < 0)
throw new NumberFormatException("Illegal digit");
// Process remaining digit groups
@@ -345,10 +347,10 @@
groupVal = Integer.parseInt(group, radix);
if (groupVal < 0)
throw new NumberFormatException("Illegal digit");
- destructiveMulAdd(mag, superRadix, groupVal);
+ destructiveMulAdd(magnitude, superRadix, groupVal);
}
// Required for cases where the array was overallocated.
- mag = trustedStripLeadingZeroInts(mag);
+ mag = trustedStripLeadingZeroInts(magnitude);
}
// Constructs a new BigInteger using a char array with radix=10
@@ -357,11 +359,11 @@
int len = val.length;
// Check for leading minus sign
- signum = 1;
+ int sign = 1;
if (val[0] == '-') {
if (len == 1)
throw new NumberFormatException("Zero length BigInteger");
- signum = -1;
+ sign = -1;
cursor = 1;
} else if (val[0] == '+') {
if (len == 1)
@@ -376,10 +378,11 @@
signum = 0;
mag = ZERO.mag;
return;
- } else {
- numDigits = len - cursor;
}
-
+
+ numDigits = len - cursor;
+ signum = sign;
+
// Pre-allocate array of expected size
int numWords;
if (len < 10) {
@@ -386,22 +389,22 @@
numWords = 1;
} else {
int numBits = (int)(((numDigits * bitsPerDigit[10]) >>> 10) + 1);
- numWords = (numBits + 31) /32;
+ numWords = (numBits + 31) >>> 5;
}
- mag = new int[numWords];
+ int[] magnitude = new int[numWords];
// Process first (potentially short) digit group
int firstGroupLen = numDigits % digitsPerInt[10];
if (firstGroupLen == 0)
firstGroupLen = digitsPerInt[10];
- mag[mag.length-1] = parseInt(val, cursor, cursor += firstGroupLen);
+ magnitude[numWords - 1] = parseInt(val, cursor, cursor += firstGroupLen);
// Process remaining digit groups
while (cursor < len) {
int groupVal = parseInt(val, cursor, cursor += digitsPerInt[10]);
- destructiveMulAdd(mag, intRadix[10], groupVal);
+ destructiveMulAdd(magnitude, intRadix[10], groupVal);
}
- mag = trustedStripLeadingZeroInts(mag);
+ mag = trustedStripLeadingZeroInts(magnitude);
}
// Create an integer with the digits between the two indexes
@@ -842,26 +845,21 @@
u2 = u.multiply(v).mod(n);
v2 = v.square().add(d.multiply(u.square())).mod(n);
- if (v2.testBit(0)) {
- v2 = n.subtract(v2);
- v2.signum = - v2.signum;
- }
+ if (v2.testBit(0))
+ v2 = v2.subtract(n);
+
v2 = v2.shiftRight(1);
-
+
u = u2; v = v2;
if (k.testBit(i)) {
u2 = u.add(v).mod(n);
- if (u2.testBit(0)) {
- u2 = n.subtract(u2);
- u2.signum = - u2.signum;
- }
+ if (u2.testBit(0))
+ u2 = u2.subtract(n);
+
u2 = u2.shiftRight(1);
-
v2 = v.add(d.multiply(u)).mod(n);
- if (v2.testBit(0)) {
- v2 = n.subtract(v2);
- v2.signum = - v2.signum;
- }
+ if (v2.testBit(0))
+ v2 = v2.subtract(n);
v2 = v2.shiftRight(1);
u = u2; v = v2;
@@ -918,11 +916,11 @@
}
/**
- * This private constructor differs from its public cousin
+ * This internal constructor differs from its public cousin
* with the arguments reversed in two ways: it assumes that its
* arguments are correct, and it doesn't copy the magnitude array.
*/
- private BigInteger(int[] magnitude, int signum) {
+ BigInteger(int[] magnitude, int signum) {
this.signum = (magnitude.length==0 ? 0 : signum);
this.mag = magnitude;
}
@@ -936,22 +934,6 @@
this.mag = stripLeadingZeroBytes(magnitude);
}
- /**
- * This private constructor is for internal use in converting
- * from a MutableBigInteger object into a BigInteger.
- */
- BigInteger(MutableBigInteger val, int sign) {
- if (val.offset > 0 || val.value.length != val.intLen) {
- mag = new int[val.intLen];
- for(int i=0; i0 ? subtract(mag, val.mag)
+ int[] resultMag = (cmp > 0 ? subtract(mag, val.mag)
: subtract(val.mag, mag));
resultMag = trustedStripLeadingZeroInts(resultMag);
- return new BigInteger(resultMag, cmp*signum);
+ return new BigInteger(resultMag, cmp == signum ? 1 : -1);
}
/**
@@ -1112,12 +1093,10 @@
// Grow result if necessary
if (carry) {
- int newLen = result.length + 1;
- int temp[] = new int[newLen];
- for (int i = 1; i0 ? subtract(mag, val.mag)
+ int[] resultMag = (cmp > 0 ? subtract(mag, val.mag)
: subtract(val.mag, mag));
resultMag = trustedStripLeadingZeroInts(resultMag);
- return new BigInteger(resultMag, cmp*signum);
+ return new BigInteger(resultMag, cmp == signum ? 1 : -1);
}
/**
@@ -1191,12 +1169,53 @@
int[] result = multiplyToLen(mag, mag.length,
val.mag, val.mag.length, null);
result = trustedStripLeadingZeroInts(result);
- return new BigInteger(result, signum*val.signum);
+ return new BigInteger(result, signum == val.signum ? 1 : -1);
}
+
+ /**
+ * Package private methods used by BigDecimal code to multiply a BigInteger
+ * with a long. Assumes v is not equal to INFLATED.
+ */
+ BigInteger multiply(long v) {
+ if (v == 0 || signum == 0)
+ return ZERO;
+ assert v != BigDecimal.INFLATED;
+ int rsign = (v > 0 ? signum : -signum);
+ if (v < 0)
+ v = -v;
+ long dh = v >>> 32; // higher order bits
+ long dl = v & LONG_MASK; // lower order bits
+ int xlen = mag.length;
+ int[] value = mag;
+ int[] rmag = (dh == 0L) ? (new int[xlen + 1]) : (new int[xlen + 2]);
+ long carry = 0;
+ int rstart = rmag.length - 1;
+ for (int i = xlen - 1; i >= 0; i--) {
+ long product = (value[i] & LONG_MASK) * dl + carry;
+ rmag[rstart--] = (int)product;
+ carry = product >>> 32;
+ }
+ rmag[rstart] = (int)carry;
+ if (dh != 0L) {
+ carry = 0;
+ rstart = rmag.length - 2;
+ for (int i = xlen - 1; i >= 0; i--) {
+ long product = (value[i] & LONG_MASK) * dh +
+ (rmag[rstart] & LONG_MASK) + carry;
+ rmag[rstart--] = (int)product;
+ carry = product >>> 32;
+ }
+ rmag[0] = (int)carry;
+ }
+ if (carry == 0L)
+ rmag = java.util.Arrays.copyOfRange(rmag, 1, rmag.length);
+ return new BigInteger(rmag, rsign);
+ }
+
/**
* Multiplies int arrays x and y to the specified lengths and places
- * the result into z.
+ * the result into z. There will be no leading zeros in the resultant array.
*/
private int[] multiplyToLen(int[] x, int xlen, int[] y, int ylen, int[] z) {
int xstart = xlen - 1;
@@ -1316,12 +1335,11 @@
*/
public BigInteger divide(BigInteger val) {
MutableBigInteger q = new MutableBigInteger(),
- r = new MutableBigInteger(),
a = new MutableBigInteger(this.mag),
b = new MutableBigInteger(val.mag);
- a.divide(b, q, r);
- return new BigInteger(q, this.signum * val.signum);
+ a.divide(b, q);
+ return q.toBigInteger(this.signum == val.signum ? 1 : -1);
}
/**
@@ -1338,12 +1356,11 @@
public BigInteger[] divideAndRemainder(BigInteger val) {
BigInteger[] result = new BigInteger[2];
MutableBigInteger q = new MutableBigInteger(),
- r = new MutableBigInteger(),
a = new MutableBigInteger(this.mag),
b = new MutableBigInteger(val.mag);
- a.divide(b, q, r);
- result[0] = new BigInteger(q, this.signum * val.signum);
- result[1] = new BigInteger(r, this.signum);
+ MutableBigInteger r = a.divide(b, q);
+ result[0] = q.toBigInteger(this.signum == val.signum ? 1 : -1);
+ result[1] = r.toBigInteger(this.signum);
return result;
}
@@ -1357,12 +1374,10 @@
*/
public BigInteger remainder(BigInteger val) {
MutableBigInteger q = new MutableBigInteger(),
- r = new MutableBigInteger(),
a = new MutableBigInteger(this.mag),
b = new MutableBigInteger(val.mag);
- a.divide(b, q, r);
- return new BigInteger(r, this.signum);
+ return a.divide(b, q).toBigInteger(this.signum);
}
/**
@@ -1418,10 +1433,17 @@
MutableBigInteger result = a.hybridGCD(b);
- return new BigInteger(result, 1);
+ return result.toBigInteger(1);
}
/**
+ * Package private method to return bit length for an integer.
+ */
+ static int bitLengthForInt(int n) {
+ return 32 - Integer.numberOfLeadingZeros(n);
+ }
+
+ /**
* Left shift int array a up to len by n bits. Returns the array that
* results from the shift since space may have to be reallocated.
*/
@@ -1428,7 +1450,7 @@
private static int[] leftShift(int[] a, int len, int n) {
int nInts = n >>> 5;
int nBits = n&0x1F;
- int bitsInHighWord = bitLen(a[0]);
+ int bitsInHighWord = bitLengthForInt(a[0]);
// If shift can be done without recopy, do so
if (n <= (32-bitsInHighWord)) {
@@ -1481,9 +1503,9 @@
* assuming there are no leading zero ints.
*/
private static int bitLength(int[] val, int len) {
- if (len==0)
+ if (len == 0)
return 0;
- return ((len-1)<<5) + bitLen(val[0]);
+ return ((len - 1) << 5) + bitLengthForInt(val[0]);
}
/**
@@ -1710,11 +1732,10 @@
int[] a = leftShift(base, base.length, modLen << 5);
MutableBigInteger q = new MutableBigInteger(),
- r = new MutableBigInteger(),
a2 = new MutableBigInteger(a),
b2 = new MutableBigInteger(mod);
- a2.divide(b2, q, r);
+ MutableBigInteger r= a2.divide(b2, q);
table[0] = r.toIntArray();
// Pad table[0] with leading zeros so its length is at least modLen
@@ -1976,7 +1997,7 @@
return this;
// Copy remaining ints of mag
- int numInts = (p+31)/32;
+ int numInts = (p + 31) >>> 5;
int[] mag = new int[numInts];
for (int i=0; i= 0))
+ if (signum < 0 || (this.compareMagnitude(m) >= 0))
modVal = this.mod(m);
if (modVal.equals(ONE))
@@ -2016,7 +2037,7 @@
MutableBigInteger b = new MutableBigInteger(m);
MutableBigInteger result = a.mutableModInverse(b);
- return new BigInteger(result, 1);
+ return result.toBigInteger(1);
}
// Shift Operations
@@ -2241,7 +2262,7 @@
if (n<0)
throw new ArithmeticException("Negative bit address");
- return (getInt(n/32) & (1 << (n%32))) != 0;
+ return (getInt(n >>> 5) & (1 << (n & 31))) != 0;
}
/**
@@ -2256,13 +2277,13 @@
if (n<0)
throw new ArithmeticException("Negative bit address");
- int intNum = n/32;
+ int intNum = n >>> 5;
int[] result = new int[Math.max(intLength(), intNum+2)];
for (int i=0; i>> 5;
+ int[] result = new int[Math.max(intLength(), ((n + 1) >>> 5) + 1)];
for (int i=0; i>> 5;
int[] result = new int[Math.max(intLength(), intNum+2)];
for (int i=0; iexcluding a sign bit.
*/
public int bitLength() {
- /*
- * Initialize bitLength field the first time this method is executed.
- * This method depends on the atomicity of int modifies; without
- * this guarantee, it would have to be synchronized.
- */
- if (bitLength == -1) {
- if (signum == 0) {
- bitLength = 0;
- } else {
+ @SuppressWarnings("deprecation") int n = bitLength - 1;
+ if (n == -1) { // bitLength not initialized yet
+ int[] m = mag;
+ int len = m.length;
+ if (len == 0) {
+ n = 0; // offset by one to initialize
+ } else {
// Calculate the bit length of the magnitude
- int magBitLength = ((mag.length-1) << 5) + bitLen(mag[0]);
-
- if (signum < 0) {
- // Check if magnitude is a power of two
- boolean pow2 = (bitCnt(mag[0]) == 1);
- for(int i=1; i>> 1;
- val = (val & 0x33333333) + ((val >>> 2) & 0x33333333);
- val = val + (val >>> 4) & 0x0f0f0f0f;
- val += val >>> 8;
- val += val >>> 16;
- return val & 0xff;
- }
-
- static int trailingZeroCnt(int val) {
- // Loop unrolled for performance
- int byteVal = val & 0xff;
- if (byteVal != 0)
- return trailingZeroTable[byteVal];
-
- byteVal = (val >>> 8) & 0xff;
- if (byteVal != 0)
- return trailingZeroTable[byteVal] + 8;
-
- byteVal = (val >>> 16) & 0xff;
- if (byteVal != 0)
- return trailingZeroTable[byteVal] + 16;
-
- byteVal = (val >>> 24) & 0xff;
- return trailingZeroTable[byteVal] + 24;
- }
-
+
// Primality Testing
/**
@@ -2536,29 +2473,41 @@
* to, or greater than {@code val}.
*/
public int compareTo(BigInteger val) {
- return (signum==val.signum
- ? signum*intArrayCmp(mag, val.mag)
- : (signum>val.signum ? 1 : -1));
+ if (signum == val.signum) {
+ switch (signum) {
+ case 1:
+ return compareMagnitude(val);
+ case -1:
+ return val.compareMagnitude(this);
+ default:
+ return 0;
+ }
+ }
+ return signum > val.signum ? 1 : -1;
}
- /*
- * Returns -1, 0 or +1 as big-endian unsigned int array arg1 is
- * less than, equal to, or greater than arg2.
+ /**
+ * Compares the magnitude array of this BigInteger with the specified
+ * BigInteger's. This is the version of compareTo ignoring sign.
+ *
+ * @param val BigInteger whose magnitude array to be compared.
+ * @return -1, 0 or 1 as this magnitude array is less than, equal to or
+ * greater than the magnitude aray for the specified BigInteger's.
*/
- private static int intArrayCmp(int[] arg1, int[] arg2) {
- if (arg1.length < arg2.length)
+ final int compareMagnitude(BigInteger val) {
+ int[] m1 = mag;
+ int len1 = m1.length;
+ int[] m2 = val.mag;
+ int len2 = m2.length;
+ if (len1 < len2)
return -1;
- if (arg1.length > arg2.length)
+ if (len1 > len2)
return 1;
-
- // Argument lengths are equal; compare the values
- for (int i=0; i b2)
- return 1;
+ for (int i = 0; i < len1; i++) {
+ int a = m1[i];
+ int b = m2[i];
+ if (a != b)
+ return ((a & LONG_MASK) < (b & LONG_MASK)) ? -1 : 1;
}
return 0;
}
@@ -2577,15 +2526,21 @@
if (!(x instanceof BigInteger))
return false;
+
BigInteger xInt = (BigInteger) x;
-
- if (xInt.signum != signum || xInt.mag.length != mag.length)
+ if (xInt.signum != signum)
return false;
+
+ int[] m = mag;
+ int len = m.length;
+ int[] xm = xInt.mag;
+ if (len != xm.length)
+ return false;
- for (int i=0; i 0) {
- int result[] = new int[val.length - keep];
- for(int i=0; i>> 2;
int[] result = new int[intLength];
int b = byteLength - 1;
for (int i = intLength-1; i >= 0; i--) {
@@ -2891,7 +2832,7 @@
result[i] = a[b--] & 0xff;
int bytesRemaining = b - keep + 1;
int bytesToTransfer = Math.min(3, bytesRemaining);
- for (int j=8; j <= 8*bytesToTransfer; j += 8)
+ for (int j=8; j <= (bytesToTransfer << 3); j += 8)
result[i] |= ((a[b--] & 0xff) << j);
}
return result;
@@ -3037,7 +2978,7 @@
* including space for at least one sign bit.
*/
private int intLength() {
- return bitLength()/32 + 1;
+ return (bitLength() >>> 5) + 1;
}
/* Returns sign bit */
@@ -3074,20 +3015,20 @@
* least significant). If the magnitude is zero, return value is undefined.
*/
private int firstNonzeroIntNum() {
- /*
- * Initialize firstNonzeroIntNum field the first time this method is
- * executed. This method depends on the atomicity of int modifies;
- * without this guarantee, it would have to be synchronized.
- */
- if (firstNonzeroIntNum == -2) {
- // Search for the first nonzero int
- int i;
- for (i=mag.length-1; i>=0 && mag[i]==0; i--)
- ;
- firstNonzeroIntNum = mag.length-i-1;
- }
- return firstNonzeroIntNum;
- }
+ int fn = firstNonzeroIntNum - 2;
+ if (fn == -2) { // firstNonzeroIntNum not initialized yet
+ fn = 0;
+
+ // Search for the first nonzero int
+ int i;
+ int mlen = mag.length;
+ for (i = mlen - 1; i >= 0 && mag[i] == 0; i--)
+ ;
+ fn = mlen - i - 1;
+ firstNonzeroIntNum = fn + 2; // offset by two to initialize
+ }
+ return fn;
+ }
/** use serialVersionUID from JDK 1.1. for interoperability */
private static final long serialVersionUID = -8287574255936472291L;
@@ -3121,6 +3062,12 @@
* deserialize it). The magnitude is read in as an array of bytes
* for historical reasons, but it is converted to an array of ints
* and the byte array is discarded.
+ * Note:
+ * The current convention is to initialize the cache fields, bitCount,
+ * bitLength and lowestSetBit, to 0 rather than some other marker value.
+ * Therefore, no explicit action to set these fields needs to be taken in
+ * readObject because those fields already have a 0 value be default since
+ * defaultReadObject is not being used.
*/
private void readObject(java.io.ObjectInputStream s)
throws java.io.IOException, ClassNotFoundException {
@@ -3136,31 +3083,46 @@
ObjectInputStream.GetField fields = s.readFields();
// Read the alternate persistent fields that we care about
- signum = fields.get("signum", -2);
+ int sign = fields.get("signum", -2);
byte[] magnitude = (byte[])fields.get("magnitude", null);
// Validate signum
- if (signum < -1 || signum > 1) {
+ if (sign < -1 || sign > 1) {
String message = "BigInteger: Invalid signum value";
if (fields.defaulted("signum"))
message = "BigInteger: Signum not present in stream";
throw new java.io.StreamCorruptedException(message);
}
- if ((magnitude.length==0) != (signum==0)) {
+ if ((magnitude.length == 0) != (sign == 0)) {
String message = "BigInteger: signum-magnitude mismatch";
if (fields.defaulted("magnitude"))
message = "BigInteger: Magnitude not present in stream";
throw new java.io.StreamCorruptedException(message);
}
+
+ // Commit final fields via Unsafe
+ unsafe.putIntVolatile(this, signumOffset, sign);
- // Set "cached computation" fields to their initial values
- bitCount = bitLength = -1;
- lowestSetBit = firstNonzeroByteNum = firstNonzeroIntNum = -2;
-
// Calculate mag field from magnitude and discard magnitude
- mag = stripLeadingZeroBytes(magnitude);
+ unsafe.putObjectVolatile(this, magOffset,
+ stripLeadingZeroBytes(magnitude));
}
+ // Support for resetting final fields while deserializing
+ private static final sun.misc.Unsafe unsafe = sun.misc.Unsafe.getUnsafe();
+ private static final long signumOffset;
+ private static final long magOffset;
+ static {
+ try {
+ signumOffset = unsafe.objectFieldOffset
+ (BigInteger.class.getDeclaredField("signum"));
+ magOffset = unsafe.objectFieldOffset
+ (BigInteger.class.getDeclaredField("mag"));
+ } catch (Exception ex) {
+ throw new Error(ex);
+ }
+ }
+
/**
* Save the {@code BigInteger} instance to a stream.
* The magnitude of a BigInteger is serialized as a byte array for
@@ -3174,6 +3136,8 @@
ObjectOutputStream.PutField fields = s.putFields();
fields.put("signum", signum);
fields.put("magnitude", magSerializedForm());
+ // The values written for cached fields are compatible with older
+ // versions, but are ignored in readObject so don't otherwise matter.
fields.put("bitCount", -1);
fields.put("bitLength", -1);
fields.put("lowestSetBit", -2);
@@ -3187,12 +3151,13 @@
* Returns the mag array as an array of bytes.
*/
private byte[] magSerializedForm() {
- int bitLen = (mag.length == 0 ? 0 :
- ((mag.length - 1) << 5) + bitLen(mag[0]));
- int byteLen = (bitLen + 7)/8;
+ int len = mag.length;
+
+ int bitLen = (len == 0 ? 0 : ((len - 1) << 5) + bitLengthForInt(mag[0]));
+ int byteLen = (bitLen + 7) >>> 3;
byte[] result = new byte[byteLen];
- for (int i=byteLen-1, bytesCopied=4, intIndex=mag.length-1, nextInt=0;
+ for (int i = byteLen - 1, bytesCopied = 4, intIndex = len - 1, nextInt = 0;
i>=0; i--) {
if (bytesCopied == 4) {
nextInt = mag[intIndex--];