134 lines
4.3 KiB
C
134 lines
4.3 KiB
C
/****************************************************************************
|
|
* libs/libc/stdio/lib_vasprintf.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 <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <stdarg.h>
|
|
#include <assert.h>
|
|
|
|
#include "libc.h"
|
|
|
|
/****************************************************************************
|
|
* Pre-processor Definitions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: vasprintf
|
|
*
|
|
* 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 vasprintf 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 vasprintf(FAR char **ptr, FAR const IPTR char *fmt, va_list ap)
|
|
{
|
|
struct lib_outstream_s nulloutstream;
|
|
struct lib_memoutstream_s memoutstream;
|
|
|
|
/* On some architectures, va_list is really a pointer to a structure on
|
|
* the stack. And the va_arg builtin will modify that instance of va_list.
|
|
* Since vasprintf traverse the parameters in the va_list twice, the
|
|
* va_list will be altered in this first cases and the second usage will
|
|
* fail. This is a known issue with x86_64.
|
|
*/
|
|
|
|
#ifdef va_copy
|
|
va_list ap2;
|
|
#endif
|
|
FAR char *buf;
|
|
int nbytes;
|
|
|
|
DEBUGASSERT(ptr && fmt);
|
|
|
|
#ifdef va_copy
|
|
va_copy(ap2, ap);
|
|
#endif
|
|
|
|
/* 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);
|
|
lib_vsprintf(&nulloutstream, fmt, ap);
|
|
|
|
/* Then allocate a buffer to hold that number of characters, adding one
|
|
* for the null terminator.
|
|
*/
|
|
|
|
buf = lib_malloc(nulloutstream.nput + 1);
|
|
if (!buf)
|
|
{
|
|
#ifdef va_copy
|
|
va_end(ap2);
|
|
#endif
|
|
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(&memoutstream, buf, nulloutstream.nput + 1);
|
|
|
|
/* Then let lib_vsprintf do it's real thing */
|
|
|
|
#ifdef va_copy
|
|
nbytes = lib_vsprintf(&memoutstream.common, fmt, ap2);
|
|
va_end(ap2);
|
|
#else
|
|
nbytes = lib_vsprintf(&memoutstream.common, fmt, ap);
|
|
#endif
|
|
|
|
/* 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).
|
|
*/
|
|
|
|
DEBUGASSERT(nbytes < 0 || nbytes == nulloutstream.nput);
|
|
|
|
if (nbytes < 0)
|
|
{
|
|
lib_free(buf);
|
|
return ERROR;
|
|
}
|
|
|
|
*ptr = buf;
|
|
return nbytes;
|
|
}
|