/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2015 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
 *   Redistribution and use in source and binary forms, with or without
 *   modification, are permitted provided that the following conditions
 *   are met:
 *
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * 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.
 *     * Neither the name of Intel Corporation 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.
 */

#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>

#include "spdk/string.h"

char *
sprintf_alloc(const char *format, ...)
{
	va_list args;
	char *buf;
	size_t bufsize;
	int rc;

	/* Try with a small buffer first. */
	bufsize = 32;

	/* Limit maximum buffer size to something reasonable so we don't loop forever. */
	while (bufsize <= 1024 * 1024) {
		buf = malloc(bufsize);
		if (buf == NULL) {
			return NULL;
		}

		va_start(args, format);
		rc = vsnprintf(buf, bufsize, format, args);
		va_end(args);

		/*
		 * If vsnprintf() returned a count within our current buffer size, we are done.
		 * The count does not include the \0 terminator, so rc == bufsize is not OK.
		 */
		if (rc >= 0 && (size_t)rc < bufsize) {
			return buf;
		}

		/*
		 * vsnprintf() should return the required space, but some libc versions do not
		 * implement this correctly, so just double the buffer size and try again.
		 *
		 * We don't need the data in buf, so rather than realloc(), use free() and malloc()
		 * again to avoid a copy.
		 */
		free(buf);
		bufsize *= 2;
	}

	return NULL;
}