LA_library/bitvector.h

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#ifndef _BITVECTOR_H_
#define _BITVECTOR_H_
#include "vec.h"
//compressed storage of large bit vectors
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//any reasonable compiler changes the dividions and modulos to shift/and instructions
typedef unsigned long bitvector_block; //should be automatically portable and efficiently use wordlength of each machine (32 vs 64)
#define blockbits (8*sizeof(bitvector_block))
inline unsigned int bitvector_rounded(unsigned int n)
{
return ((n+blockbits-1)/blockbits)*blockbits;
}
class bitvector : public NRVec<bitvector_block>
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{
private:
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unsigned int modulo;
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public:
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bitvector() : NRVec<bitvector_block>() {};
explicit bitvector (const unsigned int n):NRVec<bitvector_block>((n+blockbits-1)/blockbits) {modulo=n%blockbits;};
bitvector (const bitvector_block a, const unsigned int n):NRVec<bitvector_block>(a,(n+blockbits-1)/blockbits) {modulo=n%blockbits;};
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bitvector(const bitvector &rhs) : NRVec<bitvector_block>(rhs) {modulo=rhs.modulo;};
//operator= seems to be correctly synthetized by the compiler
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//override dereferencing to address single bits, is however possible
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//only in the const context (otherwise we would have to define a type which, when assigned to, changes a single bit - possible but probably inefficient)
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void resize(const unsigned int n) {NRVec<bitvector_block>::resize((n+blockbits-1)/blockbits); modulo=n%blockbits;};
unsigned int size() const {return (nn*blockbits)-blockbits+(modulo?modulo:blockbits);};
//arguments must be unsigned to keep the resulting assembly code simple and efficient
const bool operator[](const unsigned int i) const {return (v[i/blockbits] >>(i%blockbits))&1;};
void set(const unsigned int i) {v[i/blockbits] |= (1<<(i%blockbits));};
void reset(const unsigned int i) {v[i/blockbits] &= ~(1<<(i%blockbits));};
const bool get(const unsigned int i) {return (v[i/blockbits] >>(i%blockbits))&1;};
const bool assign(const unsigned int i, const bool r) {if(r) set(i); else reset(i); return r;};
void clear() {memset(v,0,nn*sizeof(bitvector_block));};
void fill() {memset(v,0xff,nn*sizeof(bitvector_block));};
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bool operator!=(const bitvector &rhs) const;
bool operator==(const bitvector &rhs) const {return !(*this != rhs);};
bool operator>(const bitvector &rhs) const;
bool operator<(const bitvector &rhs) const;
bool operator>=(const bitvector &rhs) const {return !(*this < rhs);};
bool operator<=(const bitvector &rhs) const {return !(*this > rhs);};
bitvector operator~() const;
bitvector& operator&=(const bitvector &rhs);
bitvector& operator|=(const bitvector &rhs);
bitvector& operator^=(const bitvector &rhs);
bitvector operator&(const bitvector &rhs) const {return bitvector(*this) &= rhs;};
bitvector operator|(const bitvector &rhs) const {return bitvector(*this) |= rhs;};
bitvector operator^(const bitvector &rhs) const {return bitvector(*this) ^= rhs;};
unsigned int population(const unsigned int before=0) const; //@@@number of 1's
//extended, truncated const i.e. not on *this but return new entity, take care of modulo's bits
//logical shifts <<= >>= << >> not implemented yet
//logical rotations not implemented yet
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};
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extern ostream & operator<<(ostream &s, const bitvector &x);
extern istream & operator>>(istream &s, bitvector &x);
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#endif