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/****************************************************************************
* lib/stdio/lib_libfwrite.c
*
* Copyright (C) 2007-2009, 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.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h> /* for CONFIG_STDIO_BUFFER_SIZE */
#include <sys/types.h>
#include <stdbool.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include "lib_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Global Constant Data
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Constant Data
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: lib_fwrite
****************************************************************************/
ssize_t lib_fwrite(FAR const void *ptr, size_t count, FAR FILE *stream)
#if CONFIG_STDIO_BUFFER_SIZE > 0
{
FAR const unsigned char *start = ptr;
FAR const unsigned char *src = ptr;
ssize_t ret = ERROR;
unsigned char *dest;
/* Make sure that writing to this stream is allowed */
if (!stream || (stream->fs_oflags & O_WROK) == 0)
{
set_errno(EBADF);
goto errout;
}
/* Get exclusive access to the stream */
lib_take_semaphore(stream);
/* If the buffer is currently being used for read access, then
* discard all of the read-ahead data. We do not support concurrent
* buffered read/write access.
*/
if (lib_rdflush(stream) < 0)
{
goto errout_with_semaphore;
}
/* Loop until all of the bytes have been buffered */
while (count > 0)
{
/* Determine the number of bytes left in the buffer */
size_t gulp_size = stream->fs_bufend - stream->fs_bufpos;
/* Will the user data fit into the amount of buffer space
* that we have left?
*/
if (gulp_size > count)
{
/* Yes, clip the gulp to the size of the user data */
gulp_size = count;
}
/* Adjust the number of bytes remaining to be transferred
* on the next pass through the loop (might be zero).
*/
count -= gulp_size;
/* Transfer the data into the buffer */
for (dest = stream->fs_bufpos; gulp_size > 0; gulp_size--)
{
*dest++ = *src++;
}
stream->fs_bufpos = dest;
/* Is the buffer full? */
if (dest >= stream->fs_bufend)
{
/* Flush the buffered data to the IO stream */
int bytes_buffered = lib_fflush(stream, false);
if (bytes_buffered < 0)
{
goto errout_with_semaphore;
}
}
}
/* Return the number of bytes written */
ret = src - start;
errout_with_semaphore:
lib_give_semaphore(stream);
errout:
return ret;
}
#else
{
return write(stream->fs_filedes, ptr, count);
}
#endif /* CONFIG_STDIO_BUFFER_SIZE */
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