/*
 * Copyright (c) 2000-2002, 2004, 2005 Sendmail, Inc. and its suppliers.
 *      All rights reserved.
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * 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.
 */

#include "sm/generic.h"
SM_RCSID("@(#)$Id: snprintf.c,v 1.13 2005/01/27 00:29:17 ca Exp $")
#include "sm/varargs.h"
#include "sm/io.h"
#include "sm/assert.h"
#include "sm/limits.h"
#include "io-int.h"

/*
**  SM_SNPRINTF -- format a string to a memory location of restricted size
**
**	Parameters:
**		str -- memory location to place formatted string
**		n -- size of buffer pointed to by str, capped to
**			a maximum of INT_MAX
**		fmt -- the formatting directives
**		... -- the data to satisfy the formatting
**
**	Returns:
**		Failure: -1
**		Success: number of bytes that would have been written
**			to str, not including the trailing '\0',
**			up to a maximum of INT_MAX, as if there was
**			no buffer size limitation.  If the result >= n
**			then the output was truncated.
**
**	Side Effects:
**		If n > 0, then between 0 and n-1 bytes of formatted output
**		are written into 'str', followed by a '\0'.
*/

int
sm_snprintf(char *str, size_t n, char const *fmt, ...)
{
	int ret;
	va_list ap;
	sm_file_T fake;

	/* While snprintf(3) specifies size_t stdio uses an int internally */
	if (n > INT_MAX)
		n = INT_MAX;
	va_start(ap, fmt);

	/* todo: put this into a static?? */
	fake.sm_magic = SM_FILE_MAGIC;
	f_fd(fake) = -1;
	f_flags(fake) = SMWR|SMSTR;
	fake.f_cookie = &fake;
	f_bfbase(fake) = f_p(fake) = (uchar *)str;
	f_bfsize(fake) = f_w(fake) = n ? n - 1 : 0;
	fake.f_timeout = SM_TIME_FOREVER;
	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;
	ret = sm_io_vfprintf(&fake, fmt, ap);
	if (n > 0)
		*f_p(fake) = '\0';
	va_end(ap);
	return ret;
}