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/************************************************************
* lib_ungetc.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name Gregory Nutt nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
************************************************************/
/************************************************************
* Compilation Switches
************************************************************/
/************************************************************
* Included Files
************************************************************/
#include <nuttx/config.h>
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <nuttx/fs.h>
#include "lib_internal.h"
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Private Type Declarations
************************************************************/
/************************************************************
* Private Function Prototypes
************************************************************/
/************************************************************
* Global Function Prototypes
************************************************************/
/**********************************************************
* Global Constant Data
**********************************************************/
/************************************************************
* Global Variables
************************************************************/
/**********************************************************
* Private Constant Data
**********************************************************/
/************************************************************
* Private Variables
**********************************************************/
/************************************************************
* Global Functions
**********************************************************/
/************************************************************
* fgetc
**********************************************************/
int ungetc(int c, FILE *stream)
{
#if CONFIG_NUNGET_CHARS > 0
int nungotten;
#endif
/* Stream must be open for read access */
if ((stream && stream->fs_filedes < 0) ||
((stream->fs_oflags & O_RDOK) == 0))
{
*get_errno_ptr() = EBADF;
return EOF;
}
#if CONFIG_NUNGET_CHARS > 0
nungotten = stream->fs_nungotten;
if (stream->fs_nungotten < CONFIG_NUNGET_CHARS)
{
stream->fs_ungotten[nungotten] = c;
stream->fs_nungotten = nungotten + 1;
return c;
}
else
#endif
{
*get_errno_ptr() = ENOMEM;
return EOF;
}
}
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