int BigUnsigned::toInt () const { return convertToSignedPrimitive< int >(); }
short BigUnsigned::toShort () const { return convertToSignedPrimitive< short>(); }
+// BIT/BLOCK ACCESSORS
+
+void BigUnsigned::setBlock(Index i, Blk newBlock) {
+ if (newBlock == 0) {
+ if (i < len) {
+ blk[i] = 0;
+ zapLeadingZeros();
+ }
+ // If i >= len, no effect.
+ } else {
+ if (i >= len) {
+ // The nonzero block extends the number.
+ allocateAndCopy(i+1);
+ // Zero any added blocks that we aren't setting.
+ for (Index j = len; j < i; j++)
+ blk[j] = 0;
+ len = i+1;
+ }
+ blk[i] = newBlock;
+ }
+}
+
+/* Evidently the compiler wants BigUnsigned:: on the return type because, at
+ * that point, it hasn't yet parsed the BigUnsigned:: on the name to get the
+ * proper scope. */
+BigUnsigned::Index BigUnsigned::bitLength() const {
+ if (isZero())
+ return 0;
+ else {
+ Blk leftmostBlock = getBlock(len - 1);
+ Index leftmostBlockLen = 0;
+ while (leftmostBlock != 0) {
+ leftmostBlock >>= 1;
+ leftmostBlockLen++;
+ }
+ return leftmostBlockLen + (len - 1) * N;
+ }
+}
+
+void BigUnsigned::setBit(Index bi, bool newBit) {
+ Index blockI = bi / N;
+ Blk block = getBlock(blockI), mask = 1 << (bi % N);
+ block = newBit ? (block | mask) : (block & ~mask);
+ setBlock(blockI, block);
+}
+
// COMPARISON
BigUnsigned::CmpRes BigUnsigned::compareTo(const BigUnsigned &x) const {
// A bigger length implies a bigger number.
template <class X> X convertToPrimitive () const;
public:
- // ACCESSORS
+ // BIT/BLOCK ACCESSORS
// Expose these from NumberlikeArray directly.
NumberlikeArray<Blk>::getCapacity;
/* Returns the requested block, or 0 if it is beyond the length (as if
* the number had 0s infinitely to the left). */
Blk getBlock(Index i) const { return i >= len ? 0 : blk[i]; }
+ void setBlock(Index i, Blk newBlock);
// The number is zero if and only if the canonical length is zero.
bool isZero() const { return NumberlikeArray<Blk>::isEmpty(); }
+ /* Returns the length of the number in bits, i.e., zero if the number
+ * is zero and otherwise one more than the largest value of bi for
+ * which getBit(bi) returns true. */
+ Index bitLength() const;
+ // Get or set bit number bi, which has value 2^bi.
+ bool getBit(Index bi) const {
+ return (getBlock(bi / N) & (1 << (bi % N))) != 0;
+ }
+ void setBit(Index bi, bool newBit);
+
// COMPARISONS
// Compares this to x like Perl's <=>
TEST(BigUnsigned(5) / 0); //error
+// Block accessors
+BigUnsigned b;
+TEST(b); //0
+TEST(b.getBlock(0)); //0
+b.setBlock(1, 314);
+// Did b grow properly? And did we zero intermediate blocks?
+TEST(check(b)); //1348619730944
+TEST(b.getLength()); //2
+TEST(b.getBlock(0)); //0
+TEST(b.getBlock(1)); //314
+// Did b shrink properly?
+b.setBlock(1, 0);
+TEST(check(b)); //0
+
+BigUnsigned bb(314);
+bb.setBlock(1, 159);
+// Make sure we used allocateAndCopy, not allocate
+TEST(bb.getBlock(0)); //314
+TEST(bb.getBlock(1)); //159
+// Blocks beyond the number should be zero regardless of whether they are
+// within the capacity.
+bb.add(1, 2);
+TEST(bb.getBlock(0)); //3
+TEST(bb.getBlock(1)); //0
+TEST(bb.getBlock(2)); //0
+TEST(bb.getBlock(314159)); //0
+
+// Bit accessors
+TEST(BigUnsigned(0).bitLength()); //0
+TEST(BigUnsigned(1).bitLength()); //1
+TEST(BigUnsigned(4095).bitLength()); //12
+TEST(BigUnsigned(4096).bitLength()); //13
+// 5 billion is between 2^32 (about 4 billion) and 2^33 (about 8 billion).
+TEST(stringToBigUnsigned("5000000000").bitLength()); //33
+
+// 25 is binary 11001.
+BigUnsigned bbb(25);
+TEST(bbb.getBit(4)); //1
+TEST(bbb.getBit(3)); //1
+TEST(bbb.getBit(2)); //0
+TEST(bbb.getBit(1)); //0
+TEST(bbb.getBit(0)); //1
+TEST(bbb.bitLength()); //5
+// Effectively add 2^32.
+bbb.setBit(32, true);
+TEST(bbb); //4294967321
+bbb.setBit(31, true);
+bbb.setBit(32, false);
+TEST(check(bbb)); //2147483673
+
BigUnsigned p1 = BigUnsigned(3) * 5;
TEST(p1); //15
/* In this case, we would like g++ to implicitly promote the BigUnsigned to a