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#ifndef __RAGELISTREAMPTR_H__
#define __RAGELISTREAMPTR_H__
#include <iostream>
#include <cassert>
class RagelIstreamPtr {
public:
RagelIstreamPtr() : istream_ref(NULL), pos(0) {}
RagelIstreamPtr(std::istream& instream,
std::streamoff off=0,
std::ios::seekdir dir=std::ios::beg);
~RagelIstreamPtr() {}
RagelIstreamPtr& operator = (std::istream *istreamPtr);
RagelIstreamPtr& operator ++ (void);
RagelIstreamPtr operator ++ (int);
RagelIstreamPtr& operator -- (void);
RagelIstreamPtr operator -- (int);
RagelIstreamPtr& operator += (int n);
RagelIstreamPtr& operator -= (int n);
std::streamoff operator - (RagelIstreamPtr const& istreamPtr);
char operator * (void);
protected:
std::istream *istream_ref;
std::streampos pos;
friend bool operator == (RagelIstreamPtr const& r1,
RagelIstreamPtr const& r2);
friend RagelIstreamPtr operator + (RagelIstreamPtr const& p, int const& n);
friend RagelIstreamPtr operator - (RagelIstreamPtr const& p, int const& n);
};
namespace std {
template<>
struct iterator_traits<RagelIstreamPtr>
{
typedef random_access_iterator_tag iterator_category;
typedef char value_type;
typedef std::streamoff difference_type;
// typedef RagelIstreamPtr pointer;
//typedef char& reference;
};
}
inline
bool operator == (RagelIstreamPtr const& r1, RagelIstreamPtr const& r2)
{
bool istream_same = (r1.istream_ref == r2.istream_ref);
bool pos_same = (r1.pos == r2.pos);
return (istream_same && pos_same);
}
inline
bool operator != (RagelIstreamPtr const& r1, RagelIstreamPtr const& r2)
{
return !(r1 == r2);
}
inline
RagelIstreamPtr operator + (RagelIstreamPtr const& p, int const& n)
{
return RagelIstreamPtr(*(p.istream_ref), p.pos+(std::streamoff)n);
}
inline
RagelIstreamPtr operator - (RagelIstreamPtr const& p, int const& n)
{
return RagelIstreamPtr(*(p.istream_ref), p.pos-(std::streamoff)n);
}
inline RagelIstreamPtr::RagelIstreamPtr(std::istream& instream,
std::streamoff off,
std::ios::seekdir dir)
: istream_ref(&instream), pos(0)
{
// save current position
std::streamoff currPos = istream_ref->tellg();
// move to given position and test
istream_ref->seekg(off, dir);
pos = istream_ref->tellg();
// restore saved position
istream_ref->seekg(currPos, std::ios::beg);
}
#if 0
inline RagelIstreamPtr::RagelIstreamPtr(std::istream *istreamPtr,
std::streampos istreamPos)
: istream_ref(istreamPtr), pos(istreamPos)
{
std::streamoff delta = pos - istreamPtr->tellg();
istream_ref->seekg(delta, std::ios::cur);
}
#endif
inline RagelIstreamPtr&
RagelIstreamPtr::operator = (std::istream *istreamPtr)
{
istream_ref = istreamPtr;
pos = std::ios::beg;
return *this;
}
inline RagelIstreamPtr& RagelIstreamPtr::operator ++ (void)
{
// istream_ref->seekg(1, std::ios::cur);
// pos = istream_ref->tellg(); // to trap errors
pos += 1;
return *this;
}
inline RagelIstreamPtr RagelIstreamPtr::operator ++ (int)
{
RagelIstreamPtr retval = *this;
// istream_ref->seekg(1, std::ios::cur);
// pos = istream_ref->tellg(); // to trap errors
pos += 1;
return retval;
}
inline RagelIstreamPtr& RagelIstreamPtr::operator -- (void)
{
// istream_ref->seekg(-1, std::ios::cur);
// pos = istream_ref->tellg(); // to trap errors
pos -= 1;
return *this;
}
inline RagelIstreamPtr RagelIstreamPtr::operator -- (int)
{
RagelIstreamPtr retval = *this;
// istream_ref->seekg(-1, std::ios::cur);
// pos = istream_ref->tellg(); // to trap errors
pos -= 1;
return retval;
}
inline RagelIstreamPtr& RagelIstreamPtr::operator += (int n)
{
// istream_ref->seekg((std::streampos) n, std::ios::cur);
// pos = istream_ref->tellg(); // to trap errors
pos += n;
return *this;
}
inline RagelIstreamPtr& RagelIstreamPtr::operator -= (int n)
{
// istream_ref->seekg((std::streampos) (-n), std::ios::cur);
// pos = istream_ref->tellg(); // to trap errors
pos -= n;
return *this;
}
// inline RagelIstreamPtr RagelIstreamPtr::operator + (int n) const
// {
// return RagelIstreamPtr(istream_ref, pos+n);
// }
//
//
// inline RagelIstreamPtr RagelIstreamPtr::operator - (int n) const
// {
// return RagelIstreamPtr(istream_ref, pos-n);
// }
inline
std::streamoff RagelIstreamPtr::operator - (RagelIstreamPtr const& istreamPtr)
{
assert(istream_ref == istreamPtr.istream_ref);
std::streamoff diff = pos - istreamPtr.pos;
return diff;
}
inline char RagelIstreamPtr::operator * (void)
{
istream_ref->seekg(pos - istream_ref->tellg(), std::ios::cur);
return istream_ref->peek();
}
#endif // __RAGELISTREAMPTR_H__
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