/* This file is part of libbrandt.
 * Copyright (C) 2016 GNUnet e.V.
 *
 * libbrandt 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.
 *
 * libbrandt 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
 * libbrandt.  If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * @file util.c
 * @brief Implementation of common utility functions.
 * @author Markus Teich
 */
#include <errno.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "util.h"


static FILE *logstream = NULL;


/**
 * setlog sets another output for logging.
 *
 * @param[in] stream The new logging target.
 */
void
setlog (FILE *stream)
{
	logstream = stream;
}


/**
 * xvprintf prints a formatstring with prefix "libbrandt: ". If the format
 * string ends with a ':', the strerror() from errno.h output will be appended.
 * The output is always terminated with a newline.
 *
 * @param[in] fmt The format string
 * @param[in] ap The inputs to the format string
 */
static void
xvprintf (const char *fmt, va_list ap)
{
	fputs ("libbrandt: ", logstream ? logstream : stderr);

	vfprintf (logstream ? logstream : stderr, fmt, ap);

	if (fmt[0] && fmt[strlen (fmt) - 1] == ':')
	{
		fputc (' ', logstream ? logstream : stderr);
		fputs (strerror (errno), logstream ? logstream : stderr);
	}
	else
	{
		fputc ('\n', logstream ? logstream : stderr);
	}
}


/**
 * eprintf prints an error message and then calls abort() to terminate the
 * process.
 *
 * @param[in] fmt The format string
 * @param[in] ... The inputs to the format string
 */
void
eprintf (const char *fmt, ...)
{
	va_list ap;

	va_start (ap, fmt);
	xvprintf (fmt, ap);
	va_end (ap);

	abort ();
}


/**
 * weprintf prints a warning message
 *
 * @param[in] fmt The format string
 * @param[in] ... The inputs to the format string
 */
void
weprintf (const char *fmt, ...)
{
	va_list ap;

	va_start (ap, fmt);
	xvprintf (fmt, ap);
	va_end (ap);
}