53 lines
1.7 KiB
C
53 lines
1.7 KiB
C
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/**
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* \file crc.c
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* Functions and types for CRC checks.
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*
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* Generated on Sun Dec 18 16:52:06 2016,
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* by pycrc v0.9, https://pycrc.org
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* using the configuration:
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* Width = 32
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* Poly = 0x04c11db7
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* Xor_In = 0xffffffff
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* ReflectIn = True
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* Xor_Out = 0xffffffff
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* ReflectOut = True
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* Algorithm = table-driven
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*****************************************************************************/
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#include "crc.h" /* include the header file generated with pycrc */
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#include <stdlib.h>
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#include <stdint.h>
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/**
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* Static table used for the table_driven implementation.
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*****************************************************************************/
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static const crc_t crc_table[16] = {
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0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac, 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
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0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c, 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c
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};
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/**
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* Update the crc value with new data.
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*
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* \param crc The current crc value.
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* \param data Pointer to a buffer of \a data_len bytes.
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* \param data_len Number of bytes in the \a data buffer.
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* \return The updated crc value.
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*****************************************************************************/
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crc_t crc_update(crc_t crc, const void *data, size_t data_len)
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{
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const unsigned char *d = (const unsigned char *)data;
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unsigned int tbl_idx;
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while (data_len--) {
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tbl_idx = crc ^ (*d >> (0 * 4));
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crc = crc_table[tbl_idx & 0x0f] ^ (crc >> 4);
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tbl_idx = crc ^ (*d >> (1 * 4));
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crc = crc_table[tbl_idx & 0x0f] ^ (crc >> 4);
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d++;
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}
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return crc & 0xffffffff;
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}
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