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74 lines
2.4 KiB
74 lines
2.4 KiB
/* utils.c - TinyCrypt platform-dependent run-time operations */ |
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/* |
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* Copyright (C) 2017 by Intel Corporation, All Rights Reserved. |
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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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* |
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* - Redistributions of source code must retain the above copyright notice, |
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* this list of conditions and the following disclaimer. |
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* |
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* - 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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* |
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* - Neither the name of Intel Corporation nor the names of its contributors |
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* may be used to endorse or promote products derived from this software |
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* 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" |
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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#include <tinycrypt/utils.h> |
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#include <tinycrypt/constants.h> |
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#include <string.h> |
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#define MASK_TWENTY_SEVEN 0x1b |
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unsigned int _copy(uint8_t *to, unsigned int to_len, |
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const uint8_t *from, unsigned int from_len) |
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{ |
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if (from_len <= to_len) { |
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(void)memcpy(to, from, from_len); |
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return from_len; |
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} else { |
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return TC_CRYPTO_FAIL; |
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} |
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} |
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void _set(void *to, uint8_t val, unsigned int len) |
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{ |
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(void)memset(to, val, len); |
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} |
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/* |
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* Doubles the value of a byte for values up to 127. |
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*/ |
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uint8_t _double_byte(uint8_t a) |
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{ |
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return ((a<<1) ^ ((a>>7) * MASK_TWENTY_SEVEN)); |
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} |
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int _compare(const uint8_t *a, const uint8_t *b, size_t size) |
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{ |
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const uint8_t *tempa = a; |
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const uint8_t *tempb = b; |
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uint8_t result = 0; |
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for (unsigned int i = 0; i < size; i++) { |
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result |= tempa[i] ^ tempb[i]; |
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} |
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return result; |
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}
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