60 wiersze
1.3 KiB
C++
60 wiersze
1.3 KiB
C++
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// mods by James Zahary Dec 28, 2021 https://github.com/jameszah/ESPxWebFlMgr
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// based on https://github.com/holgerlembke/ESPxWebFlMgr
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//
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// Copyright (c) 2013 Christopher Baker <https://christopherbaker.net>
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//
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// SPDX-License-Identifier: MIT
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//
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#include "CRC32.h"
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// Conditionally use pgm memory if it is available.
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#if defined(PROGMEM)
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#define FLASH_PROGMEM PROGMEM
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#define FLASH_READ_DWORD(x) (pgm_read_dword_near(x))
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#else
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#define FLASH_PROGMEM
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#define FLASH_READ_DWORD(x) (*(uint32_t*)(x))
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#endif
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static const uint32_t crc32_table[] FLASH_PROGMEM = {
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0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
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0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
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0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
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0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
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};
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CRC32::CRC32()
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{
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reset();
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}
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void CRC32::reset()
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{
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_state = ~0L;
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}
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void CRC32::update(const uint8_t& data)
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{
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// via http://forum.arduino.cc/index.php?topic=91179.0
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uint8_t tbl_idx = 0;
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tbl_idx = _state ^ (data >> (0 * 4));
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_state = FLASH_READ_DWORD(crc32_table + (tbl_idx & 0x0f)) ^ (_state >> 4);
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tbl_idx = _state ^ (data >> (1 * 4));
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_state = FLASH_READ_DWORD(crc32_table + (tbl_idx & 0x0f)) ^ (_state >> 4);
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}
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uint32_t CRC32::finalize() const
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{
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return ~_state;
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}
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