1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80
|
// valuesetter.h
/******************************************************************************
*
* MiXViews - an X window system based sound & data editor/processor
*
* Copyright (c) 1993, 1994 Regents of the University of California
*
* Author: Douglas Scott
* Date: December 13, 1994
*
* Permission to use, copy and modify this software and its documentation
* for research and/or educational purposes and without fee is hereby granted,
* provided that the above copyright notice appear in all copies and that
* both that copyright notice and this permission notice appear in
* supporting documentation. The author reserves the right to distribute this
* software and its documentation. The University of California and the author
* make no representations about the suitability of this software for any
* purpose, and in no event shall University of California be liable for any
* damage, loss of data, or profits resulting from its use.
* It is provided "as is" without express or implied warranty.
*
******************************************************************************/
// ValueSetters, instantiated via templates, allow members of structs to be
// correctly loaded with values from disk, regardless of the in-memory
// offsets of the individual members. Any necessary byte-swapping is handled
// here for cross-platform file i/o.
#ifndef VALUESETTER_H
#define VALUESETTER_H
#include "byteswap.h"
#include "datafile.h"
class ValueSetterBase {
public:
virtual int readAndSet(DataFile *)=0;
virtual int writeTo(DataFile *)=0;
};
template <class T>
class ValueSetter : public ValueSetterBase {
public:
ValueSetter(T* ptr) : myPtr(ptr) {}
redefined int readAndSet(DataFile *f) {
int good = f->read((char *) myPtr, sizeof(*myPtr)).good();
if(f->bytesAreSwapped()) *myPtr = swap(*myPtr);
return good;
}
redefined int writeTo(DataFile *f) {
T temp = f->bytesAreSwapped() ? swap(*myPtr) : *(const T *)myPtr;
return f->write((char *) &temp, sizeof(temp)).good();
}
private:
T* myPtr;
};
template <class T>
inline ValueSetter<T>* newValueSetter(T* ptr) {
return new ValueSetter<T>(ptr);
}
// BlockSetters allow reading and writing of undifferentiated char blocks
class BlockSetter : public ValueSetterBase {
public:
BlockSetter(char* ptr, LONG nbytes) : myPtr(ptr), bytes(nbytes) {}
redefined int readAndSet(DataFile *f) {
return f->read(myPtr, bytes).good();
}
redefined int writeTo(DataFile *f) {
return f->write(myPtr, bytes).good();
}
private:
char* myPtr;
long bytes;
};
#endif
|