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freebsd/contrib/sendmail/libsm/vsnprintf.c
2002-06-11 21:12:04 +00:00

79 lines
1.9 KiB
C

/*
* Copyright (c) 2000-2001 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/gen.h>
SM_RCSID("@(#)$Id: vsnprintf.c,v 1.23 2001/09/11 04:04:49 gshapiro Exp $")
#include <limits.h>
#include <sm/io.h>
#include "local.h"
/*
** SM_VSNPRINTF -- format data for "output" into a string
**
** Assigned 'str' to a "fake" file pointer. This allows common
** o/p formatting function sm_vprintf() to be used.
**
** Parameters:
** str -- location for output
** n -- maximum size for o/p
** fmt -- format directives
** ap -- data unit vectors for use by 'fmt'
**
** Results:
** result from sm_io_vfprintf()
**
** Side Effects:
** Limits the size ('n') to INT_MAX.
*/
int
sm_vsnprintf(str, n, fmt, ap)
char *str;
size_t n;
const char *fmt;
SM_VA_LOCAL_DECL
{
int ret;
char dummy;
SM_FILE_T fake;
/* While snprintf(3) specifies size_t stdio uses an int internally */
if (n > INT_MAX)
n = INT_MAX;
/* Stdio internals do not deal correctly with zero length buffer */
if (n == 0)
{
str = &dummy;
n = 1;
}
fake.sm_magic = SmFileMagic;
fake.f_timeout = SM_TIME_FOREVER;
fake.f_timeoutstate = SM_TIME_BLOCK;
fake.f_file = -1;
fake.f_flags = SMWR | SMSTR;
fake.f_bf.smb_base = fake.f_p = (unsigned char *)str;
fake.f_bf.smb_size = fake.f_w = n - 1;
fake.f_close = NULL;
fake.f_open = NULL;
fake.f_read = NULL;
fake.f_write = NULL;
fake.f_seek = NULL;
fake.f_setinfo = fake.f_getinfo = NULL;
fake.f_type = "sm_vsnprintf:fake";
ret = sm_io_vfprintf(&fake, SM_TIME_FOREVER, fmt, ap);
*fake.f_p = 0;
return ret;
}