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rpointer.h

gehe zur Dokumentation dieser Datei

#ifndef RPOINTER_H
#define RPOINTER_H
#include<assert.h>
#include"mseg.h"
#include<sys/types.h>

namespace RAMS
{

 class RPointer_s
 {
 protected:
    Mseg *seg;
    off_t* off;
    off_t  soff; 
 public:
    RPointer_s() { seg=(Mseg *)NULL;off=(off_t *)NULL; }
    RPointer_s(Mseg *s,off_t& o):seg(s),off(&o) {}
    RPointer_s(Mseg *s,off_t& o,off_t koff):seg(s),off(&o) { *off=koff; }
    RPointer_s(off_t koff,Mseg *s):seg(s),off(&soff),soff(koff) {}
    void init(Mseg *s,off_t& o) { seg=s; off=&o; }
    void init(off_t koff,Mseg *s) { off=&soff; soff=koff; seg=s; }
    off_t offset() const { return *off; }
    
    int ok() { return *off>=0 && *off < off_t(seg->length()); }
    size_t operator-(RPointer_s a)
        {
            assert(a.seg->begin()==seg->begin());
            return (*off-*(a.off));
        }

    void setoff(off_t o) { *off=o; }
    RPointer_s& cast(const RPointer_s &anderer)
    {
        seg=anderer.seg;
        *off=*(anderer.off);
        return *this;
    }
    
    void *operator=(void *p)
    {
      *off=(char *)p - (char *)(seg->begin());
      assert(ok());
      return p;
    }
    
    bool operator==(const RPointer_s& other) const
    {
      return (seg->begin()==other.seg->begin() && offset() == other.offset());
    }
 };

 template<class T,int SIZE=sizeof(T)> class RPointer : public RPointer_s
 {
 public:
    RPointer():RPointer_s() {}
    RPointer(Mseg *s,off_t& o):RPointer_s(s,o) {}
    RPointer(Mseg *s,off_t& o,off_t koff):RPointer_s(s,o,koff) {}
    RPointer(off_t o,Mseg *s):RPointer_s(o,s) {}
    RPointer(const RPointer_s& a) { cast(a); }
    RPointer(Mseg *s,T* ap):RPointer_s((char *)ap - (char *)(s->begin()),s) {}
    RPointer(Mseg *s,off_t &o,T* ap)
     :RPointer(s,o,(char *)ap - (char *)(s->begin())) {}
    T *ptr() { return (T *)((char *)(seg->begin()) + *off); }
    T *operator->() { return ptr(); }
    T& operator*()  { return *ptr(); }
    RPointer<T,SIZE>& operator=(RPointer<T,SIZE>& anderer)
    {
      if(seg == 0)
      { // Initialisierung 
        seg=anderer.seg;
        off=&soff;
        *off=*(anderer.off);
      }
      else if(seg->begin()==anderer.seg->begin())
      {
        *off=*(anderer.off);
      }
      else
      {
        // wie anderer Zeiger
        *off=(char *)(anderer.ptr()) - (char *)(seg->begin());
      }
      assert(ok());
      return *this;
    }
    T *operator+=(off_t dazu)
    { *off+=dazu*SIZE;
      assert(ok());
      return ptr();
    }
    T *operator-=(off_t dazu)
    { *off-=dazu*SIZE;
      assert(*off >= 0);
      return ptr();
    }
    T *operator=(T *p)
    {
      *off=(char *)p - (char *)(seg->begin());
      assert(ok());
      return p;
    }
 };

 typedef RPointer<char> RcharPointer;
};

inline long align2(long a,long w)
{
   long e= (w & ~(a-1));
   if(e == w)  return e;
   else        return e+a;
}
#endif

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