mosesdecoder/moses/FilePtr.h

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// $Id$
/* ---------------------------------------------------------------- */
/* Copyright 2005 (c) by RWTH Aachen - Lehrstuhl fuer Informatik VI */
/* Richard Zens */
/* ---------------------------------------------------------------- */
#ifndef moses_FilePtr_h
#define moses_FilePtr_h
#include "File.h"
namespace Moses
{
/** smart pointer for on-demand loading from file
* requirement: T has a constructor T(FILE*)
*/
template<typename T> class FilePtr
{
public:
typedef T* Ptr;
private:
FILE* f;
OFF_T pos;
mutable Ptr t;
public:
FilePtr(FILE* f_=0,OFF_T p=0) : f(f_),pos(p),t(0) {}
~FilePtr() {}
void set(FILE* f_,OFF_T p) {
f=f_;
pos=p;
}
void free() {
delete t;
t=0;
}
T& operator* () {
load();
return *t;
}
Ptr operator->() {
load();
return t;
}
operator Ptr () {
load();
return t;
}
const T& operator* () const {
load();
return *t;
}
Ptr operator->() const {
load();
return t;
}
operator Ptr () const {
load();
return t;
}
// direct access to pointer, use with care!
Ptr getPtr() {
return t;
}
Ptr getPtr() const {
return t;
}
operator bool() const {
return (f && pos!=InvalidOffT);
}
void load() const {
if(t) return;
if(f && pos!=InvalidOffT) {
fSeek(f,pos);
t=new T(f);
}
}
};
}
#endif