/*
 * utils.c
 * Miscellaneous utilities for string manipulation
 *
 * Copyright (c) 2013 Federico Mena Quintero
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdarg.h>
#include <stdlib.h>
#include <string.h>

#include "utils.h"

#ifndef HAVE_STPCPY
/**
 * Copy characters from one string into another
 *
 * @note: The strings should not overlap, as the behavior is undefined.
 *
 * @s1: The source string.
 * @s2: The destination string.
 *
 * @return a pointer to the terminating `\0' character of @s1,
 * or NULL if @s1 or @s2 is NULL.
 */
char *stpcpy(char * s1, const char * s2)
{
	if (s1 == NULL || s2 == NULL)
		return NULL;

	strcpy(s1, s2);

	return s1 + strlen(s2);
}
#endif

/**
 * Concatenate strings into a newly allocated string
 *
 * @note: Specify NULL for the last string in the varargs list
 *
 * @str: The first string in the list
 * @...: Subsequent strings.  Use NULL for the last item.
 *
 * @return a newly allocated string, or NULL if @str is NULL.  This will also
 * return NULL and set errno to ENOMEM if memory is exhausted.
 */
char *string_concat(const char *str, ...)
{
	size_t len;
	va_list args;
	char *s;
	char *result;
	char *dest;

	if (!str)
		return NULL;

	/* Compute final length */

	len = strlen(str) + 1; /* plus 1 for the null terminator */

	va_start(args, str);
	s = va_arg(args, char *);
	while (s) {
		len += strlen(s);
		s = va_arg(args, char*);
	}
	va_end(args);

	/* Concat each string */

	result = malloc(len);
	if (!result)
		return NULL; /* errno remains set */

	dest = result;

	dest = stpcpy(dest, str);

	va_start(args, str);
	s = va_arg(args, char *);
	while (s) {
		dest = stpcpy(dest, s);
		s = va_arg(args, char *);
	}
	va_end(args);

	return result;
}