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