/*
 * Copyright (c) 2000-2002, 2004 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 *
 * By using this file, you agree to the terms and conditions set
 * forth in the LICENSE file which can be found at the top level of
 * the sendmail distribution.
 */

/*
 * Copyright (c) 1997 Todd C. Miller <Todd.Miller@courtesan.com>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND TODD C. MILLER DISCLAIMS ALL
 * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL TODD C. MILLER BE LIABLE
 * FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
 * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
 * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include "sm/generic.h"
SM_RCSID("@(#)$Id: vasprintf.c,v 1.10 2004/12/29 23:47:35 ca Exp $")
#include "sm/varargs.h"
#include "sm/io.h"
#include "sm/assert.h"
#include "sm/heap.h"
#include "io-int.h"

/*
**  SM_VASPRINTF -- printf to a dynamically allocated string
**
**  Write 'printf' output to a dynamically allocated string
**  buffer which is returned to the caller.
**
**	Parameters:
**		str -- *str receives a pointer to the allocated string
**		fmt -- format directives for printing
**		ap -- variable argument list
**
**	Results:
**		On failure, set *str to NULL, set errno, and return -1.
**
**		On success, set *str to a pointer to a nul-terminated
**		string buffer containing printf output,	and return the
**		length of the string (not counting the nul).
*/

#define SM_VA_BUFSIZE	128

int
sm_vasprintf(char **str, const char *fmt, va_list ap)
{
	int ret;
	sm_file_T fake;
	uchar *base;

	fake.sm_magic = SM_FILE_MAGIC;
	f_fd(fake) = -1;
	f_flags(fake) = SMWR | SMSTR | SMALC;
	f_bfbase(fake) = f_p(fake) = (uchar *)sm_malloc(SM_VA_BUFSIZE);
	if (f_bfbase(fake) == NULL)
		goto err2;
	f_read(fake) = NULL;
	f_write(fake) = NULL;
	f_close(fake) = NULL;
	f_open(fake) = NULL;
	f_seek(fake) = NULL;
	f_setinfo(fake) = f_getinfo(fake) = NULL;
	f_bfsize(fake) = f_w(fake) = SM_VA_BUFSIZE - 1;
	fake.f_timeout = SM_TIME_FOREVER;
	ret = sm_io_vfprintf(&fake, fmt, ap);
	if (ret == -1)
		goto err;
	*f_p(fake) = '\0';

	/* use no more space than necessary */
	base = (uchar *) sm_realloc(f_bfbase(fake), ret + 1);
	if (base == NULL)
		goto err;
	*str = (char *)base;
	return ret;

err:
	if (f_bfbase(fake) != NULL)
	{
		sm_free(f_bfbase(fake));
		f_bfbase(fake) = NULL;
	}
err2:
	*str = NULL;
	errno = ENOMEM;
	return -1;
}