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#pragma once
#include "types.h"
#define FMODE_READ 1
#define FMODE_WRITE 2
#define FMODE_APPEND 4
#define FMODE_MAX_VALUE (FMODE_READ | FMODE_WRITE | FMODE_APPEND)
struct vnode;
typedef struct file
{
/*
* The current position in the file. Can be modified by system calls
* like lseek(2), read(2), and write(2) (and possibly others) as
* described in the man pages of those calls.
*/
size_t f_pos;
/*
* The mode in which this file was opened. This is a mask of the flags
* FMODE_READ, FMODE_WRITE, and FMODE_APPEND. It is set when the file
* is first opened, and use to restrict the operations that can be
* performed on the underlying vnode.
*/
unsigned int f_mode;
/*
* The number of references to this struct.
*/
size_t f_refcount;
/*
* The vnode which corresponds to this file.
*/
struct vnode *f_vnode;
} file_t;
struct file *fcreate(int fd, struct vnode *vnode, unsigned int mode);
/*
* Returns the file_t assiciated with the given file descriptor for the
* current process. If there is no associated file_t, returns NULL.
*/
struct file *fget(int fd);
/*
* fref() increments the reference count on the given file.
*/
void fref(file_t *file);
/*
* fput() decrements the reference count on the given file.
*
* If the refcount reaches 0, the storage for the given file_t will be
* released (f won't point to a valid memory address anymore), and the
* refcount on the associated vnode (if any) will be decremented.
*
* The vnode release operation will also be called if it exists.
*/
void fput(file_t **filep);
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