tor-android/external/badvpn_dns/misc/bsize.h

118 lines
3.3 KiB
C

/**
* @file bsize.h
* @author Ambroz Bizjak <ambrop7@gmail.com>
*
* @section LICENSE
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* @section DESCRIPTION
*
* Arithmetic with overflow detection.
*/
#ifndef BADVPN_MISC_BSIZE_H
#define BADVPN_MISC_BSIZE_H
#include <stddef.h>
#include <limits.h>
#include <stdint.h>
typedef struct {
int is_overflow;
size_t value;
} bsize_t;
static bsize_t bsize_fromsize (size_t v);
static bsize_t bsize_fromint (int v);
static bsize_t bsize_overflow (void);
static int bsize_tosize (bsize_t s, size_t *out);
static int bsize_toint (bsize_t s, int *out);
static bsize_t bsize_add (bsize_t s1, bsize_t s2);
static bsize_t bsize_max (bsize_t s1, bsize_t s2);
static bsize_t bsize_mul (bsize_t s1, bsize_t s2);
bsize_t bsize_fromsize (size_t v)
{
bsize_t s = {0, v};
return s;
}
bsize_t bsize_fromint (int v)
{
bsize_t s = {(v < 0 || v > SIZE_MAX), v};
return s;
}
static bsize_t bsize_overflow (void)
{
bsize_t s = {1, 0};
return s;
}
int bsize_tosize (bsize_t s, size_t *out)
{
if (s.is_overflow) {
return 0;
}
if (out) {
*out = s.value;
}
return 1;
}
int bsize_toint (bsize_t s, int *out)
{
if (s.is_overflow || s.value > INT_MAX) {
return 0;
}
if (out) {
*out = s.value;
}
return 1;
}
bsize_t bsize_add (bsize_t s1, bsize_t s2)
{
bsize_t s = {(s1.is_overflow || s2.is_overflow || s2.value > SIZE_MAX - s1.value), (s1.value + s2.value)};
return s;
}
bsize_t bsize_max (bsize_t s1, bsize_t s2)
{
bsize_t s = {(s1.is_overflow || s2.is_overflow), ((s1.value > s2.value) * s1.value + (s1.value <= s2.value) * s2.value)};
return s;
}
bsize_t bsize_mul (bsize_t s1, bsize_t s2)
{
bsize_t s = {(s1.is_overflow || s2.is_overflow || (s1.value != 0 && s2.value > SIZE_MAX / s1.value)), (s1.value * s2.value)};
return s;
}
#endif