rcstring2.h
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#ifndef __RCSTRING_H__
#define __RCSTRING_H__
#include <iostream>
#include <mutex>
#include <stdio.h>
#include <string.h>
using namespace std;
class rcstring {
struct rctext;
rctext* data;
public:
class Range {};
class Cref;
rcstring();
rcstring(const char*);
rcstring(const rcstring&);
~rcstring();
rcstring& operator=(const rcstring&);
rcstring& operator+=(const rcstring&);
rcstring operator+(const rcstring&) const;
friend ostream& operator<<(ostream&, const rcstring&);
void check(unsigned int i) const;
char read(unsigned int i) const;
void write(unsigned int i, char c);
char operator[](unsigned int i) const;
Cref operator[](unsigned int i);
unsigned int getRefCount();
};
struct rcstring::rctext {
char* s;
unsigned int size;
unsigned int n;
std::mutex mutex;
rctext(unsigned int nsize, const char* p)
{
n = 1;
size = nsize;
s = new char[size + 1];
strncpy(s, p, size);
s[size] = '\0';
};
~rctext()
{
delete[] s;
};
unsigned int AtomicRead()
{
unsigned int retval;
mutex.lock();
retval = n;
mutex.unlock();
return retval;
};
unsigned int AtomicIncrement()
{
mutex.lock();
unsigned int retval = ++n;
mutex.unlock();
return retval;
};
unsigned int AtomicDecrement()
{
mutex.lock();
unsigned int retval = --n;
mutex.unlock();
return retval;
};
private:
rctext(const rctext&);
rctext& operator=(const rctext&);
};
class rcstring::Cref {
friend class rcstring;
rcstring& s;
int i;
Cref(rcstring& ss, unsigned int ii) : s(ss), i(ii){};
public:
operator char() const
{
return s.read(i);
}
rcstring::Cref& operator=(char c)
{
s.write(i, c);
return *this;
};
rcstring::Cref& operator=(const Cref& ref)
{
return operator=((char)ref);
};
};
inline rcstring::rcstring()
{
data = new rctext(0, "");
}
inline rcstring::rcstring(const rcstring& x)
{
x.data->AtomicIncrement();
data = x.data;
}
inline rcstring::~rcstring()
{
if (data->AtomicDecrement() == 0)
delete data;
}
rcstring& rcstring::operator=(const rcstring& x)
{
rctext* olddata = data;
x.data->AtomicIncrement();
data = x.data;
if (olddata->AtomicDecrement() == 0)
delete olddata;
return *this;
}
rcstring::rcstring(const char* s)
{
data = new rctext(strlen(s), s);
}
ostream& operator<<(ostream& o, const rcstring& s)
{
return o << s.data->s;
}
rcstring& rcstring::operator+=(const rcstring& s)
{
int newsize = data->size + s.data->size;
rctext* newdata = new rctext(newsize, data->s);
strcat(newdata->s, s.data->s);
rctext* olddata = data;
data = newdata;
if (olddata->AtomicDecrement() == 0)
delete olddata;
return *this;
}
rcstring rcstring::operator+(const rcstring& s) const
{
return rcstring(*this) += s;
}
inline void rcstring::check(unsigned int i) const
{
if (data->size <= i)
throw Range();
}
inline char rcstring::read(unsigned int i) const
{
return data->s[i];
}
inline void rcstring::write(unsigned int i, char c)
{
if (data->AtomicRead() > 1) {
rctext* newdata = new rctext(data->size, data->s);
rctext* olddata = data;
data = newdata;
if (olddata->AtomicDecrement() == 0)
delete olddata;
}
data->s[i] = c;
}
char rcstring::operator[](unsigned int i) const
{
check(i);
return data->s[i];
}
rcstring::Cref rcstring::operator[](unsigned int i)
{
check(i);
return Cref(*this, i);
}
unsigned int rcstring::getRefCount()
{
return data->AtomicRead();
;
}
#endif /* __RCSTRING_H__ */