/* util.c  -- Various error checking wrappers and utilities.
 *
 *  Copyright (C) 2016 Tomasz Kramkowski <tk@the-tk.com>
 *
 *  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 2 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, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Some contents of this file (indicated below) are based on work covered by
 * the following copyright and permission notice:
 *
 *  Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
 *
 *  Permission to use, copy, modify, and distribute this software for any
 *  purpose with or without fee is hereby granted, provided that the above
 *  copyright notice and this permission notice appear in all copies.
 *
 *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <assert.h>
#include <errno.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>

#include "log.h"
#include "util.h"

/* szadd: checked size_t addition */
size_t szadd(size_t a, size_t b)
{
	if (SIZE_MAX - a < b)
		error(0, EMSG_SZOP);

	return a + b;
}

/* szmul: checked size_t multiplication
 * License information can be found at the top of this file */
size_t szmul(size_t a, size_t b)
{
#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof (size_t) * 4))
	if ((a >= MUL_NO_OVERFLOW || b >= MUL_NO_OVERFLOW) &&
		a > 0 && SIZE_MAX / a < b)
		error(0, EMSG_SZOP);
#undef MUL_NO_OVERFLOW

	return a * b;
}

/* xstrmalloc: allocate for a string (+1) or exit with error */
void *xstrmalloc(size_t size)
{
	size_t nsize;

	nsize = size + 1;
	if (nsize < size)
		error(0, EMSG_ALLOC);

	return xmalloc(nsize);
}

/* xstrdup: duplicae string or exit with error */
char *xstrdup(const char *s)
{
	char *ret;

	assert(s);

	ret = xstrmalloc(strlen(s));
	strcpy(ret, s);

	return ret;
}

/* xrealloc: reallocate or exit with error */
void *xrealloc(void *p, size_t size)
{
	p = realloc(p, size);
	if (!p)
		error(errno, EMSG_ALLOC);

	return p;
}

/* xmalloc: allocate or exit with error */
void *xmalloc(size_t size)
{
	return xrealloc(NULL, size);
}

/* xstrcut: cut out a bit of a string into a new string */
char *xstrcut(const char *s, size_t offt, size_t len)
{
	char *ret;

	ret = xstrmalloc(len);
	strncpy(ret, s + offt, len + 1);

	return ret;
}

/* xstrcasecmp: case insensitive strcmp */
int xstrcasecmp(const char *s1, const char *s2)
{
	while (toupper(*s1++) == toupper(*s2++))
		if (*s1 == '\0' || *s2 == '\0')
			break;
	if (*s1 == *s2)
		return 0;
	if (*s1 < *s2)
		return -1;
	return 1;
}