/*
* Matt McCutchen's Big Integer Library
-* http://mysite.verizon.net/mccutchen/bigint/
*/
#include "BigInteger.hh"
sign = zero; // NumberlikeArray did the rest
else {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = positive;
len = 1;
blk[0] = Blk(x);
BigInteger::BigInteger(long x) {
if (x > 0) {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = positive;
len = 1;
blk[0] = Blk(x);
} else if (x < 0) {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = negative;
len = 1;
blk[0] = Blk(-x);
sign = zero;
else {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = positive;
len = 1;
blk[0] = Blk(x);
BigInteger::BigInteger(int x) {
if (x > 0) {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = positive;
len = 1;
blk[0] = Blk(x);
} else if (x < 0) {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = negative;
len = 1;
blk[0] = Blk(-x);
sign = zero;
else {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = positive;
len = 1;
blk[0] = Blk(x);
BigInteger::BigInteger(short x) {
if (x > 0) {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = positive;
len = 1;
blk[0] = Blk(x);
} else if (x < 0) {
cap = 1;
- blk2 = new Blk[1];
+ blk = new Blk[1];
sign = negative;
len = 1;
blk[0] = Blk(-x);
// These do some messing around to determine the sign of the result,
// then call one of BigUnsigned's put-heres.
+// See remarks about aliased calls in BigUnsigned.cc .
+#define DOTR_ALIASED(cond, op) \
+ if (cond) { \
+ BigInteger tmpThis; \
+ tmpThis.op; \
+ *this = tmpThis; \
+ return; \
+ }
+
// Addition
void BigInteger::add(const BigInteger &a, const BigInteger &b) {
- // Block unsafe calls
- if (this == &a || this == &b)
- throw "BigInteger::add: One of the arguments is the invoked object";
+ DOTR_ALIASED(this == &a || this == &b, add(a, b));
// If one argument is zero, copy the other.
if (a.sign == zero)
operator =(b);
void BigInteger::subtract(const BigInteger &a, const BigInteger &b) {
// Notice that this routine is identical to BigInteger::add,
// if one replaces b.sign by its opposite.
- // Block unsafe calls
- if (this == &a || this == &b)
- throw "BigInteger::subtract: One of the arguments is the invoked object";
+ DOTR_ALIASED(this == &a || this == &b, subtract(a, b));
// If a is zero, copy b and flip its sign. If b is zero, copy a.
if (a.sign == zero) {
BigUnsigned::operator =(b);
- sign = Sign(-sign);
+ // Take the negative of _b_'s, sign, not ours.
+ // Bug pointed out by Sam Larkin on 2005.03.30.
+ sign = Sign(-b.sign);
} else if (b.sign == zero)
- operator =(a);
+ operator =(a);
// If their signs differ, take a.sign and add the magnitudes.
else if (a.sign != b.sign) {
sign = a.sign;
// Multiplication
void BigInteger::multiply(const BigInteger &a, const BigInteger &b) {
- // Block unsafe calls
- if (this == &a || this == &b)
- throw "BigInteger::multiply: One of the arguments is the invoked object";
+ DOTR_ALIASED(this == &a || this == &b, multiply(a, b));
// If one object is zero, copy zero and return.
if (a.sign == zero || b.sign == zero) {
sign = zero;
* -4 -3 1 -1
*/
void BigInteger::divideWithRemainder(const BigInteger &b, BigInteger &q) {
- // Block unsafe calls
- if (this == &b || this == &q || &b == &q)
- throw "BigInteger::divideWithRemainder: One of the arguments is the invoked object";
+ // Defend against aliased calls;
+ // same idea as in BigUnsigned::divideWithRemainder .
+ if (this == &q)
+ throw "BigInteger::divideWithRemainder: Cannot write quotient and remainder into the same variable";
+ if (this == &b || &q == &b) {
+ BigInteger tmpB(b);
+ divideWithRemainder(tmpB, q);
+ return;
+ }
+
// Division by zero gives quotient 0 and remainder *this
if (b.sign == zero) {
q.len = 0;
// Negation
void BigInteger::negate(const BigInteger &a) {
- // Block unsafe calls
- if (this == &a)
- throw "BigInteger::negate: The argument is the invoked object";
+ DOTR_ALIASED(this == &a, negate(a));
// Copy a's magnitude
BigUnsigned::operator =(a);
// Copy the opposite of a.sign