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dpavlin |
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/* |
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* Cisco 7200 (Predator) simulation platform. |
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* Copyright (c) 2006 Christophe Fillot (cf@utc.fr) |
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* |
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* CRC functions. |
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*/ |
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#include <stdio.h> |
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#include <stdlib.h> |
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#include <unistd.h> |
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#include <string.h> |
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#include <sys/types.h> |
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#include <sys/stat.h> |
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#include <sys/mman.h> |
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#include <signal.h> |
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#include <fcntl.h> |
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#include <assert.h> |
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#include "utils.h" |
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#include "crc.h" |
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#define CRC12_POLY 0x0f01 |
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#define CRC16_POLY 0xa001 |
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#define CRC32_POLY 0xedb88320L |
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/* CRC tables */ |
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m_uint16_t crc12_array[256],crc16_array[256]; |
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m_uint32_t crc32_array[256]; |
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/* Initialize CRC-12 algorithm */ |
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static void crc12_init(void) |
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{ |
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m_uint16_t crc,c; |
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int i,j; |
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for(i=0;i<256;i++) { |
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crc = 0; |
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c = (m_uint16_t)i; |
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for(j=0;j<8;j++) { |
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if ((crc ^ c) & 0x0001) |
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crc = (crc >> 1) ^ CRC12_POLY; |
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else |
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crc = crc >> 1; |
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c = c >> 1; |
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} |
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crc12_array[i] = crc; |
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} |
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} |
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/* Initialize CRC-16 algorithm */ |
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static void crc16_init(void) |
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{ |
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m_uint16_t crc,c; |
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int i,j; |
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for(i=0;i<256;i++) { |
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crc = 0; |
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c = (m_uint16_t)i; |
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for(j=0;j<8;j++) { |
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if ((crc ^ c) & 0x0001) |
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crc = (crc >> 1) ^ CRC16_POLY; |
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else |
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crc = crc >> 1; |
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c = c >> 1; |
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} |
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crc16_array[i] = crc; |
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} |
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} |
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/* Initialize CRC-32 algorithm */ |
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static void crc32_init(void) |
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{ |
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unsigned long c; |
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int n, k; |
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for (n=0;n<256;n++) { |
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c = (unsigned long) n; |
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for (k = 0; k < 8; k++) { |
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if (c & 1) |
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c = CRC32_POLY ^ (c >> 1); |
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else |
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c = c >> 1; |
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} |
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crc32_array[n] = c; |
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} |
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} |
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/* Initialize CRC algorithms */ |
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void crc_init(void) |
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{ |
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crc12_init(); |
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crc16_init(); |
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crc32_init(); |
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} |