diff options
Diffstat (limited to 'nuttx/libc/stdio/lib_ungetc.c')
-rw-r--r-- | nuttx/libc/stdio/lib_ungetc.c | 121 |
1 files changed, 121 insertions, 0 deletions
diff --git a/nuttx/libc/stdio/lib_ungetc.c b/nuttx/libc/stdio/lib_ungetc.c new file mode 100644 index 000000000..178aeddd1 --- /dev/null +++ b/nuttx/libc/stdio/lib_ungetc.c @@ -0,0 +1,121 @@ +/**************************************************************************** + * libc/stdio/lib_ungetc.c + * + * Copyright (C) 2007, 2008, 2011 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt <gnutt@nuttx.org> + * + * 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 NuttX 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/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 + **************************************************************************/ + +/**************************************************************************** + * Public Functions + **************************************************************************/ + +/**************************************************************************** + * Name: ungetc + **************************************************************************/ + +int ungetc(int c, FAR 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)) + { + set_errno(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 + { + set_errno(ENOMEM); + return EOF; + } +} + |