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Diffstat (limited to 'nuttx/lib/stdio/lib_fseek.c')
-rw-r--r-- | nuttx/lib/stdio/lib_fseek.c | 138 |
1 files changed, 138 insertions, 0 deletions
diff --git a/nuttx/lib/stdio/lib_fseek.c b/nuttx/lib/stdio/lib_fseek.c new file mode 100644 index 000000000..a68de79fe --- /dev/null +++ b/nuttx/lib/stdio/lib_fseek.c @@ -0,0 +1,138 @@ +/**************************************************************************** + * lib/stdio/lib_fseek.c + * + * Copyright (C) 2007, 2008, 2011 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 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 <sys/types.h> +#include <stdio.h> +#include <unistd.h> +#include <fcntl.h> +#include <errno.h> + +#include "lib_internal.h" + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Type Declarations + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Global Constant Data + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Constant Data + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: fseek + * + * Description: + * The fseek() function sets the file position indicator for the stream + * pointed to by stream. The new position, measured in bytes, is obtained + * by adding offset bytes to the position specified by whence. If whence is + * set to SEEK_SET, SEEK_CUR, or SEEK_END, the offset is relative to the + * start of the file, the current position indicator, or end-of-file, + * respectively. A successful call to the fseek() function clears the + * end-of-file indicator for the stream and undoes any effects of the ungetc(3) + * function on the same stream. + * + * Returned Value: + * Zero on succes; -1 on failure with errno set appropriately. + * + ****************************************************************************/ + +int fseek(FAR FILE *stream, long int offset, int whence) +{ + #if CONFIG_STDIO_BUFFER_SIZE > 0 + /* Flush any valid read/write data in the buffer (also verifies stream) */ + + if (lib_rdflush(stream) < 0 || lib_wrflush(stream) < 0) + { + return ERROR; + } +#else + /* Verify that we were provided with a stream */ + + if (!stream) + { + set_errno(EBADF); + return ERROR; + } +#endif + + /* On success or failure, discard any characters saved by ungetc() */ + +#if CONFIG_NUNGET_CHARS > 0 + stream->fs_nungotten = 0; +#endif + + /* Perform the fseek on the underlying file descriptor */ + + return lseek(stream->fs_filedes, offset, whence) == (off_t)-1 ? ERROR : OK; +} + + |