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/* vasprintf and asprintf with out-of-memory checking.
Copyright (C) 1999, 2002-2004, 2006-2020 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
#include <config.h>
/* Specification. */
#include "xvasprintf.h"
#include <errno.h>
#include <limits.h>
#include <string.h>
#include <stdio.h>
#include "xalloc.h"
/* Checked size_t computations. */
#include "xsize.h"
static char *
xstrcat (size_t argcount, va_list args)
{
char *result;
va_list ap;
size_t totalsize;
size_t i;
char *p;
/* Determine the total size. */
totalsize = 0;
va_copy (ap, args);
for (i = argcount; i > 0; i--)
{
const char *next = va_arg (ap, const char *);
totalsize = xsum (totalsize, strlen (next));
}
va_end (ap);
/* Test for overflow in the summing pass above or in (totalsize + 1) below.
Also, don't return a string longer than INT_MAX, for consistency with
vasprintf(). */
if (totalsize == SIZE_MAX || totalsize > INT_MAX)
{
errno = EOVERFLOW;
return NULL;
}
/* Allocate and fill the result string. */
result = XNMALLOC (totalsize + 1, char);
p = result;
for (i = argcount; i > 0; i--)
{
const char *next = va_arg (args, const char *);
size_t len = strlen (next);
memcpy (p, next, len);
p += len;
}
*p = '\0';
return result;
}
char *
xvasprintf (const char *format, va_list args)
{
char *result;
/* Recognize the special case format = "%s...%s". It is a frequently used
idiom for string concatenation and needs to be fast. We don't want to
have a separate function xstrcat() for this purpose. */
{
size_t argcount = 0;
const char *f;
for (f = format;;)
{
if (*f == '\0')
/* Recognized the special case of string concatenation. */
return xstrcat (argcount, args);
if (*f != '%')
break;
f++;
if (*f != 's')
break;
f++;
argcount++;
}
}
if (vasprintf (&result, format, args) < 0)
{
if (errno == ENOMEM)
xalloc_die ();
return NULL;
}
return result;
}
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