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jiri 2006-03-30 19:16:40 +00:00
parent a5015f5c3c
commit 8f8b5b855f
2 changed files with 51 additions and 16 deletions
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17
bitvector.cc Normal file
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#include "bitvector.h"
//inefficient I/O operators
ostream & operator<<(ostream &s, const bitvector &x)
{
for(unsigned int i=0; i<x.size(); ++i) s<< x[i];
return s;
}
istream & operator>>(istream &s, bitvector &x)
{
bool a;
for(unsigned int i=0; i<x.size(); ++i) {s >>a; x.assign(i,a);}
return s;
}

50
bitvector.h
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@ -4,26 +4,44 @@
#include "vec.h"
//compressed storage of large bit vectors
class bitvector : public NRVec<unsigned char>
//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>
{
private:
int modulo;
unsigned int modulo;
public:
bitvector() : NRVec<unsigned char>() {};
explicit bitvector (const int n):NRVec<unsigned char>((n+7)>>3) {modulo=n&7;};
bitvector (const int a, const int n):NRVec<unsigned char>(a,(n+7)>>3) {modulo=n&7;};
bitvector(const bitvector &rhs) : NRVec<unsigned char>(rhs) {};
//overrige dereferencing to address single bits, is however possible
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;};
bitvector(const bitvector &rhs) : NRVec<bitvector_block>(rhs) {};
//override dereferencing to address single bits, is however possible
//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)
void resize(const int n) {NRVec<unsigned char>::resize((n+7)>>3); modulo=n&7;};
const int size() const {return (nn<<3)-8+modulo?modulo:8;};
const bool operator[](const int i) const {return (v[i>>3] >>(i&7))&1;};
void set(const int i) {v[i>>3] |= (1<<(i&7));};
void reset(const int i) {v[i>>3] &= ~(1<<(i&7));};
const bool get(const int i) {return (v[i>>3] >>(i&7))&1;};
const bool assign(const int i, const bool r) {if(r) set(i); else reset(i); return r;};
void clear() {memset(v,0,nn);};
void fill() {memset(v,0xff,nn);};
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));};
const bool operator!=(const bitvector &rhs) const {};
const bool operator==(const bitvector &rhs) const {return !(*this != rhs);};
};
extern ostream & operator<<(ostream &s, const bitvector &x);
extern istream & operator>>(istream &s, bitvector &x);
#endif