| /* utils.c - TinyCrypt platform-dependent run-time operations */ |
| |
| /* |
| * Copyright (C) 2017 by Intel Corporation, All Rights Reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions are met: |
| * |
| * - Redistributions of source code must retain the above copyright notice, |
| * this list of conditions and the following disclaimer. |
| * |
| * - 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. |
| * |
| * - Neither the name of Intel Corporation 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 COPYRIGHT OWNER OR CONTRIBUTORS 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. |
| */ |
| |
| #include <tinycrypt/utils.h> |
| #include <tinycrypt/constants.h> |
| |
| #include <string.h> |
| |
| #define MASK_TWENTY_SEVEN 0x1b |
| |
| unsigned int _copy(uint8_t *to, unsigned int to_len, |
| const uint8_t *from, unsigned int from_len) |
| { |
| if (from_len <= to_len) { |
| (void)memcpy(to, from, from_len); |
| return from_len; |
| } else { |
| return TC_CRYPTO_FAIL; |
| } |
| } |
| |
| void _set(void *to, uint8_t val, unsigned int len) |
| { |
| (void)memset(to, val, len); |
| } |
| |
| /* |
| * Doubles the value of a byte for values up to 127. |
| */ |
| uint8_t _double_byte(uint8_t a) |
| { |
| return ((a<<1) ^ ((a>>7) * MASK_TWENTY_SEVEN)); |
| } |
| |
| int _compare(const uint8_t *a, const uint8_t *b, size_t size) |
| { |
| const uint8_t *tempa = a; |
| const uint8_t *tempb = b; |
| uint8_t result = 0; |
| |
| for (unsigned int i = 0; i < size; i++) { |
| result |= tempa[i] ^ tempb[i]; |
| } |
| return result; |
| } |