273 lines
7.3 KiB
C
273 lines
7.3 KiB
C
/* Copyright (C) 2007 Eric Blake
|
|
* Permission to use, copy, modify, and distribute this software
|
|
* is freely granted, provided that this notice is preserved.
|
|
*/
|
|
|
|
/*
|
|
FUNCTION
|
|
<<funopen>>, <<fropen>>, <<fwopen>>---open a stream with custom callbacks
|
|
|
|
INDEX
|
|
funopen
|
|
INDEX
|
|
fropen
|
|
INDEX
|
|
fwopen
|
|
|
|
SYNOPSIS
|
|
#include <stdio.h>
|
|
FILE *funopen(const void *<[cookie]>,
|
|
int (*<[readfn]>) (void *cookie, char *buf, int n),
|
|
int (*<[writefn]>) (void *cookie, const char *buf, int n),
|
|
fpos_t (*<[seekfn]>) (void *cookie, fpos_t off, int whence),
|
|
int (*<[closefn]>) (void *cookie));
|
|
FILE *fropen(const void *<[cookie]>,
|
|
int (*<[readfn]>) (void *cookie, char *buf, int n));
|
|
FILE *fwopen(const void *<[cookie]>,
|
|
int (*<[writefn]>) (void *cookie, const char *buf, int n));
|
|
|
|
DESCRIPTION
|
|
<<funopen>> creates a <<FILE>> stream where I/O is performed using
|
|
custom callbacks. At least one of <[readfn]> and <[writefn]> must be
|
|
provided, which determines whether the stream behaves with mode <"r">,
|
|
<"w">, or <"r+">.
|
|
|
|
<[readfn]> should return -1 on failure, or else the number of bytes
|
|
read (0 on EOF). It is similar to <<read>>, except that <int> rather
|
|
than <size_t> bounds a transaction size, and <[cookie]> will be passed
|
|
as the first argument. A NULL <[readfn]> makes attempts to read the
|
|
stream fail.
|
|
|
|
<[writefn]> should return -1 on failure, or else the number of bytes
|
|
written. It is similar to <<write>>, except that <int> rather than
|
|
<size_t> bounds a transaction size, and <[cookie]> will be passed as
|
|
the first argument. A NULL <[writefn]> makes attempts to write the
|
|
stream fail.
|
|
|
|
<[seekfn]> should return (fpos_t)-1 on failure, or else the current
|
|
file position. It is similar to <<lseek>>, except that <[cookie]>
|
|
will be passed as the first argument. A NULL <[seekfn]> makes the
|
|
stream behave similarly to a pipe in relation to stdio functions that
|
|
require positioning. This implementation assumes fpos_t and off_t are
|
|
the same type.
|
|
|
|
<[closefn]> should return -1 on failure, or 0 on success. It is
|
|
similar to <<close>>, except that <[cookie]> will be passed as the
|
|
first argument. A NULL <[closefn]> merely flushes all data then lets
|
|
<<fclose>> succeed. A failed close will still invalidate the stream.
|
|
|
|
Read and write I/O functions are allowed to change the underlying
|
|
buffer on fully buffered or line buffered streams by calling
|
|
<<setvbuf>>. They are also not required to completely fill or empty
|
|
the buffer. They are not, however, allowed to change streams from
|
|
unbuffered to buffered or to change the state of the line buffering
|
|
flag. They must also be prepared to have read or write calls occur on
|
|
buffers other than the one most recently specified.
|
|
|
|
The functions <<fropen>> and <<fwopen>> are convenience macros around
|
|
<<funopen>> that only use the specified callback.
|
|
|
|
RETURNS
|
|
The return value is an open FILE pointer on success. On error,
|
|
<<NULL>> is returned, and <<errno>> will be set to EINVAL if a
|
|
function pointer is missing, ENOMEM if the stream cannot be created,
|
|
or EMFILE if too many streams are already open.
|
|
|
|
PORTABILITY
|
|
This function is a newlib extension, copying the prototype from BSD.
|
|
It is not portable. See also the <<fopencookie>> interface from Linux.
|
|
|
|
Supporting OS subroutines required: <<sbrk>>.
|
|
*/
|
|
|
|
#include <stdio.h>
|
|
#include <errno.h>
|
|
#include <sys/lock.h>
|
|
#include "local.h"
|
|
|
|
typedef int (*funread)(void *_cookie, char *_buf, _READ_WRITE_BUFSIZE_TYPE _n);
|
|
typedef int (*funwrite)(void *_cookie, const char *_buf,
|
|
_READ_WRITE_BUFSIZE_TYPE _n);
|
|
#ifdef __LARGE64_FILES
|
|
typedef _fpos64_t (*funseek)(void *_cookie, _fpos64_t _off, int _whence);
|
|
#else
|
|
typedef fpos_t (*funseek)(void *_cookie, fpos_t _off, int _whence);
|
|
#endif
|
|
typedef int (*funclose)(void *_cookie);
|
|
|
|
typedef struct funcookie {
|
|
void *cookie;
|
|
funread readfn;
|
|
funwrite writefn;
|
|
funseek seekfn;
|
|
funclose closefn;
|
|
} funcookie;
|
|
|
|
static _READ_WRITE_RETURN_TYPE
|
|
funreader (struct _reent *ptr,
|
|
void *cookie,
|
|
char *buf,
|
|
_READ_WRITE_BUFSIZE_TYPE n)
|
|
{
|
|
int result;
|
|
funcookie *c = (funcookie *) cookie;
|
|
errno = 0;
|
|
if ((result = c->readfn (c->cookie, buf, n)) < 0 && errno)
|
|
ptr->_errno = errno;
|
|
return result;
|
|
}
|
|
|
|
static _READ_WRITE_RETURN_TYPE
|
|
funwriter (struct _reent *ptr,
|
|
void *cookie,
|
|
const char *buf,
|
|
_READ_WRITE_BUFSIZE_TYPE n)
|
|
{
|
|
int result;
|
|
funcookie *c = (funcookie *) cookie;
|
|
errno = 0;
|
|
if ((result = c->writefn (c->cookie, buf, n)) < 0 && errno)
|
|
ptr->_errno = errno;
|
|
return result;
|
|
}
|
|
|
|
static _fpos_t
|
|
funseeker (struct _reent *ptr,
|
|
void *cookie,
|
|
_fpos_t off,
|
|
int whence)
|
|
{
|
|
funcookie *c = (funcookie *) cookie;
|
|
#ifndef __LARGE64_FILES
|
|
fpos_t result;
|
|
errno = 0;
|
|
if ((result = c->seekfn (c->cookie, (fpos_t) off, whence)) < 0 && errno)
|
|
ptr->_errno = errno;
|
|
#else /* __LARGE64_FILES */
|
|
_fpos64_t result;
|
|
errno = 0;
|
|
if ((result = c->seekfn (c->cookie, (_fpos64_t) off, whence)) < 0 && errno)
|
|
ptr->_errno = errno;
|
|
else if ((_fpos_t)result != result)
|
|
{
|
|
ptr->_errno = EOVERFLOW;
|
|
result = -1;
|
|
}
|
|
#endif /* __LARGE64_FILES */
|
|
return result;
|
|
}
|
|
|
|
#ifdef __LARGE64_FILES
|
|
static _fpos64_t
|
|
funseeker64 (struct _reent *ptr,
|
|
void *cookie,
|
|
_fpos64_t off,
|
|
int whence)
|
|
{
|
|
_fpos64_t result;
|
|
funcookie *c = (funcookie *) cookie;
|
|
errno = 0;
|
|
if ((result = c->seekfn (c->cookie, off, whence)) < 0 && errno)
|
|
ptr->_errno = errno;
|
|
return result;
|
|
}
|
|
#endif /* __LARGE64_FILES */
|
|
|
|
static int
|
|
funcloser (struct _reent *ptr,
|
|
void *cookie)
|
|
{
|
|
int result = 0;
|
|
funcookie *c = (funcookie *) cookie;
|
|
if (c->closefn)
|
|
{
|
|
errno = 0;
|
|
if ((result = c->closefn (c->cookie)) < 0 && errno)
|
|
ptr->_errno = errno;
|
|
}
|
|
_free_r (ptr, c);
|
|
return result;
|
|
}
|
|
|
|
FILE *
|
|
_funopen_r (struct _reent *ptr,
|
|
const void *cookie,
|
|
funread readfn,
|
|
funwrite writefn,
|
|
funseek seekfn,
|
|
funclose closefn)
|
|
{
|
|
FILE *fp;
|
|
funcookie *c;
|
|
|
|
if (!readfn && !writefn)
|
|
{
|
|
ptr->_errno = EINVAL;
|
|
return NULL;
|
|
}
|
|
if ((fp = __sfp (ptr)) == NULL)
|
|
return NULL;
|
|
if ((c = (funcookie *) _malloc_r (ptr, sizeof *c)) == NULL)
|
|
{
|
|
_newlib_sfp_lock_start ();
|
|
fp->_flags = 0; /* release */
|
|
#ifndef __SINGLE_THREAD__
|
|
__lock_close_recursive (fp->_lock);
|
|
#endif
|
|
_newlib_sfp_lock_end ();
|
|
return NULL;
|
|
}
|
|
|
|
_newlib_flockfile_start (fp);
|
|
fp->_file = -1;
|
|
c->cookie = (void *) cookie; /* cast away const */
|
|
fp->_cookie = c;
|
|
if (readfn)
|
|
{
|
|
c->readfn = readfn;
|
|
fp->_read = funreader;
|
|
if (writefn)
|
|
{
|
|
fp->_flags = __SRW;
|
|
c->writefn = writefn;
|
|
fp->_write = funwriter;
|
|
}
|
|
else
|
|
{
|
|
fp->_flags = __SRD;
|
|
c->writefn = NULL;
|
|
fp->_write = NULL;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
fp->_flags = __SWR;
|
|
c->writefn = writefn;
|
|
fp->_write = funwriter;
|
|
c->readfn = NULL;
|
|
fp->_read = NULL;
|
|
}
|
|
c->seekfn = seekfn;
|
|
fp->_seek = seekfn ? funseeker : NULL;
|
|
#ifdef __LARGE64_FILES
|
|
fp->_seek64 = seekfn ? funseeker64 : NULL;
|
|
fp->_flags |= __SL64;
|
|
#endif
|
|
c->closefn = closefn;
|
|
fp->_close = funcloser;
|
|
_newlib_flockfile_end (fp);
|
|
return fp;
|
|
}
|
|
|
|
#ifndef _REENT_ONLY
|
|
FILE *
|
|
funopen (const void *cookie,
|
|
funread readfn,
|
|
funwrite writefn,
|
|
funseek seekfn,
|
|
funclose closefn)
|
|
{
|
|
return _funopen_r (_REENT, cookie, readfn, writefn, seekfn, closefn);
|
|
}
|
|
#endif /* !_REENT_ONLY */
|