/*

 * snprintf.c - Implement snprintf and vsnprintf on platforms that need them.

 */

/*

 * Copyright (C) 2006, 2007 the Free Software Foundation, Inc.

 *

 * This file is part of GAWK, the GNU implementation of the

 * AWK Programming Language.

 *

 * GAWK 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.

 *

 * GAWK 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, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA

 */

/* If using in a multi-threaded context, then SNPRINTF_REENTRANT must be

   defined.   But in that case, performance will be much worse, since a

   temporary file is created and closed for each call to snprintf. */

#if defined(HAVE_MKSTEMP)

/* If mkstemp is available, use it instead of tmpfile(), since some older

   implementations of tmpfile() were not secure. */

static char *tmpfilename = NULL;

static FILE *safe_f = NULL;

#ifdef HAVE_ATEXIT

static void close_safe_f()

{

	if (safe_f != NULL) {

		fclose(safe_f);

		safe_f = NULL;

	}

	if (tmpfilename != NULL) {

		unlink(tmpfilename);

		free(tmpfilename);

		tmpfilename = NULL;

	}

}

#endif

static FILE *

safe_tmpfile (void)

{

	static bool first = true;

	static const char template[] = "snprintfXXXXXX";

	int fd;

	static char *tmpdir = NULL;

	static int len = 0;

	if (first) {

		first = false;

		/*

		 * First try Unix stanadard env var, then Windows var,

		 * then fall back to /tmp.

		 */

		if ((tmpdir = getenv("TMPDIR")) != NULL && *tmpdir != '\0')

			;	/* got it */

		else if ((tmpdir = getenv("TEMP")) != NULL && *tmpdir != '\0')

			;	/* got it */

		else

			tmpdir = "/tmp";

		len = strlen(tmpdir) + 1 + strlen(template) + 1;

#ifdef HAVE_ATEXIT

		atexit(close_safe_f);

#endif /* HAVE_ATEXIT */

	}

	if ((tmpfilename = (char *) malloc(len)) == NULL)

		return NULL;

	else

		sprintf(tmpfilename, "%s/%s", tmpdir, template);

	if ((fd = mkstemp (tmpfilename)) < 0)

		return NULL;

#if ! defined(__DJGPP__) && ! defined(MSDOS) && ! defined(_MSC_VER) \

	&& ! defined(_WIN32) && ! defined(__CRTRSXNT__) && ! defined(__EMX__) \

	&& ! defined(__MINGW32__) && ! defined(__WIN32__)

	/* If not MS or OS/2, unlink after opening. */

	unlink (tmpfilename);

	free(tmpfilename);

	tmpfilename = NULL;

#endif

	if ((safe_f = fdopen (fd, "w+b")) == NULL) {

		close (fd);

		return NULL;

	}

	/* setvbuf(f,NULL,_IOFBF,4*BUFSIZ); */

	return safe_f;

}

#elif defined(HAVE_TMPFILE)

#define safe_tmpfile tmpfile

#else

#error Neither mkstemp() nor tmpfile() is available on this platform.

#endif

#if (__STDC_VERSION__ + 0) < 199901

#undef restrict	/* force it! */

#define restrict

#endif

int

vsnprintf (char *restrict buf, size_t len,

		const char *restrict fmt, va_list args)

{

	int actual;

	int nread;

	size_t cnt = 0;

#ifndef SNPRINTF_REENTRANT

	static

#endif

	FILE *fp;

	if ((buf == NULL) || (len < 1))

		return -1;

	buf[0] = '\0';	/* in case the caller does not check the return code! */

#ifdef SNPRINTF_REENTRANT

	if ((fp = safe_tmpfile ()) == NULL)

		return -1;

#else

	if ((fp == NULL) && ((fp = safe_tmpfile ()) == NULL))

		return -1;

	rewind (fp);

#endif

	actual = vfprintf (fp, fmt, args);

	rewind (fp);

	if (actual < 0) {

#ifdef SNPRINTF_REENTRANT

		fclose (fp);

		if (tmpfilename != NULL) {

			unlink(tmpfilename);

			free(tmpfilename);

			tmpfilename = NULL;

		}

#endif

		return -1;

	}

	else if ((size_t) actual < len)

		len = actual;

	else

		--len;

	while (cnt < len && (nread = fread (buf + cnt, 1, len - cnt, fp)) > 0)

		cnt += nread;

	buf[cnt] = '\0';

#ifdef SNPRINTF_REENTRANT

	fclose (fp);

	if (tmpfilename != NULL) {

		unlink(tmpfilename);

		free(tmpfilename);

		tmpfilename = NULL;

	}

#endif

	if (cnt < len)

		return -1;

	return actual;

}

int

snprintf (char *restrict buf, size_t len, const char *restrict fmt, ...)

{

	int rv;

	va_list args;

	va_start (args, fmt);

	rv = vsnprintf (buf, len, fmt, args);

	va_end (args);

	return rv;

}