57 lines
1.9 KiB
C
57 lines
1.9 KiB
C
/*
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* ESPRESSIF MIT License
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*
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* Copyright (c) 2020 <ESPRESSIF SYSTEMS (SHANGHAI) PTE LTD>
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*
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* Permission is hereby granted for use on ESPRESSIF SYSTEMS products only, in which case,
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* it is free of charge, to any person obtaining a copy of this software and associated
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* documentation files (the "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
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* and/or sell copies of the Software, and to permit persons to whom the Software is furnished
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* to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in all copies or
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* substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
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* FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
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* COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
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* IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*
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*/
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#include <stdint.h>
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#include <esp_system.h>
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/**
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* @bref Obtain a series of random bytes
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*
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* @param buf the random bytes were copied point
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* len the number of bytes requested
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*
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* @return the result
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* > 0 : the number of bytes that were copied to the buffer
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* others : failed
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*/
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int esp_mfi_get_random(uint8_t *buf, uint16_t len)
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{
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int i, j;
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unsigned long tmp;
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for (i = 0; i < ((len + 3) & ~3) / 4; i++) {
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tmp = esp_random();
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for (j = 0; j < 4; j++) {
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if ((i * 4 + j) < len) {
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buf[i * 4 + j] = (uint8_t) (tmp >> (j * 8));
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} else {
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break;
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}
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}
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}
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return len;
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}
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