/****************************************************************************
* libc/stdio/lib_avsprintf.c
*
* Copyright (C) 2011-2012 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 <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <assert.h>
#include "lib_internal.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/****************************************************************************
* Global Constant Data
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Constant Data
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Global Functions
****************************************************************************/
/****************************************************************************
* Name: avsprintf
*
* Description:
* This function is similar to vsprintf, except that it dynamically
* allocates a string (as with malloc) to hold the output, instead of
* putting the output in a buffer you allocate in advance. The ptr
* argument should be the address of a char * object, and a successful
* call to avsprintf stores a pointer to the newly allocated string at that
* location.
*
* Returned Value:
* The returned value is the number of characters allocated for the buffer,
* or less than zero if an error occurred. Usually this means that the buffer
* could not be allocated.
*
****************************************************************************/
int avsprintf(FAR char **ptr, const char *fmt, va_list ap)
{
struct lib_outstream_s nulloutstream;
struct lib_memoutstream_s memoutstream;
FAR char *buf;
int nbytes;
DEBUGASSERT(ptr && fmt);
/* First, use a nullstream to get the size of the buffer. The number
* of bytes returned may or may not include the null terminator.
*/
lib_nulloutstream(&nulloutstream);
nbytes = lib_vsprintf((FAR struct lib_outstream_s *)&nulloutstream, fmt, ap);
/* Then allocate a buffer to hold that number of characters, adding one
* for the null terminator.
*/
buf = (FAR char *)malloc(nulloutstream.nput + 1);
if (!buf)
{
return ERROR;
}
/* Initialize a memory stream to write into the allocated buffer. The
* memory stream will reserve one byte at the end of the buffer for the
* null terminator and will not report this in the number of output bytes.
*/
lib_memoutstream((FAR struct lib_memoutstream_s *)&memoutstream,
buf, nulloutstream.nput + 1);
/* Then let lib_vsprintf do it's real thing */
nbytes = lib_vsprintf((FAR struct lib_outstream_s *)&memoutstream.public, fmt, ap);
/* Return a pointer to the string to the caller. NOTE: the memstream put()
* method has already added the NUL terminator to the end of the string (not
* included in the nput count).
*
* Hmmm.. looks like the memory would be stranded if lib_vsprintf() returned
* an error. Does that ever happen?
*/
DEBUGASSERT(nbytes < 0 || nbytes == nulloutstream.nput);
*ptr = buf;
return nbytes;
}
