nuttx/libs/libc/stdio/lib_vsnprintf.c
Alin Jerpelea b7c451c5a4 libs: Gregory Nutt: update licenses to Apache
Gregory Nutt has submitted the SGA and we can migrate the licenses
 to Apache.

Signed-off-by: Alin Jerpelea <alin.jerpelea@sony.com>
2021-04-02 11:12:25 -05:00

78 lines
2.5 KiB
C

/****************************************************************************
* libs/libc/stdio/lib_vsnprintf.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <stdio.h>
#include "libc.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: vsnprintf
****************************************************************************/
int vsnprintf(FAR char *buf, size_t size, FAR const IPTR char *format,
va_list ap)
{
union
{
struct lib_outstream_s nulloutstream;
struct lib_memoutstream_s memoutstream;
} u;
FAR struct lib_outstream_s *stream;
int n;
/* "If the value of [size] is zero on a call to vsnprintf(), nothing shall
* be written, the number of bytes that would have been written had [size]
* been sufficiently large excluding the terminating null shall be
* returned, and [buf] may be a null pointer." -- opengroup.org
*/
if (size > 0)
{
/* Initialize a memory stream to write to the buffer */
lib_memoutstream(&u.memoutstream, buf, size);
stream = &u.memoutstream.public;
}
else
{
/* Use a null stream to get the size of the buffer */
lib_nulloutstream(&u.nulloutstream);
stream = &u.nulloutstream;
}
/* Then let lib_vsprintf do the real work */
n = lib_vsprintf(stream, format, ap);
return n;
}