sortix-mirror/libc/stdio/fflush_stop_writing_unlocked.c

68 lines
1.8 KiB
C

/*
* Copyright (c) 2012, 2013, 2014 Jonas 'Sortie' Termansen.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
* stdio/fflush_stop_writing_unlocked.c
* Resets the FILE to a consistent state so it is ready for reading.
*/
#include <sys/types.h>
#include <errno.h>
#include <limits.h>
#include <stdint.h>
#include <stdio.h>
int fflush_stop_writing_unlocked(FILE* fp)
{
if ( !(fp->flags & _FILE_LAST_WRITE) )
return 0;
if ( !(fp->flags & _FILE_WRITABLE) )
return errno = EBADF, fp->flags |= _FILE_STATUS_ERROR, EOF;
if ( !fp->write_func )
return errno = EBADF, fp->flags |= _FILE_STATUS_ERROR, EOF;
int result = 0;
size_t count = fp->amount_output_buffered;
size_t sofar = 0;
while ( sofar < count )
{
size_t request = count - sofar;
if ( (size_t) SSIZE_MAX < request )
request = SSIZE_MAX;
ssize_t amount = fp->write_func(fp->user, fp->buffer + sofar, request);
if ( amount < 0 )
{
fp->flags |= _FILE_STATUS_ERROR;
result = EOF;
break;
}
if ( amount == 0 )
{
fp->flags |= _FILE_STATUS_EOF;
result = EOF;
break;
}
sofar += amount;
}
fp->amount_output_buffered = 0;
fp->flags &= ~_FILE_LAST_WRITE;
return result;
}