1 | //crc.c: |
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2 | |
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3 | /* |
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4 | * Copyright (C) Philipp 'ph3-der-loewe' Schafft - 2010-2011 |
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5 | * |
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6 | * This file is part of libroar a part of RoarAudio, |
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7 | * a cross-platform sound system for both, home and professional use. |
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8 | * See README for details. |
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9 | * |
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10 | * This file is free software; you can redistribute it and/or modify |
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11 | * it under the terms of the GNU General Public License version 3 |
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12 | * as published by the Free Software Foundation. |
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13 | * |
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14 | * libroar is distributed in the hope that it will be useful, |
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15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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17 | * GNU General Public License for more details. |
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18 | * |
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19 | * You should have received a copy of the GNU General Public License |
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20 | * along with this software; see the file COPYING. If not, write to |
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21 | * the Free Software Foundation, 51 Franklin Street, Fifth Floor, |
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22 | * Boston, MA 02110-1301, USA. |
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23 | * |
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24 | * NOTE for everyone want's to change something and send patches: |
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25 | * read README and HACKING! There a addition information on |
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26 | * the license of this document you need to read before you send |
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27 | * any patches. |
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28 | * |
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29 | * NOTE for uses of non-GPL (LGPL,...) software using libesd, libartsc |
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30 | * or libpulse*: |
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31 | * The libs libroaresd, libroararts and libroarpulse link this lib |
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32 | * and are therefore GPL. Because of this it may be illigal to use |
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33 | * them with any software that uses libesd, libartsc or libpulse*. |
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34 | */ |
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35 | |
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36 | #include "libroar.h" |
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37 | |
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38 | #define CRC24_POLY 0x01864CFBL |
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39 | #define CRC24_INIT 0x00B704CEL |
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40 | |
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41 | uint32_t roar_crc24_add(uint32_t state, const void * data, size_t len) { |
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42 | const unsigned char * p = data; |
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43 | int i; |
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44 | |
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45 | if ( data == NULL ) |
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46 | return CRC24_INIT; |
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47 | |
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48 | for (; len; len--) { |
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49 | state ^= (*p++) << 16; |
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50 | for (i = 0; i < 8; i++) { |
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51 | state <<= 1; |
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52 | if ( state & 0x01000000 ) |
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53 | state ^= CRC24_POLY; |
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54 | } |
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55 | } |
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56 | |
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57 | return state & 0x00FFFFFFL; |
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58 | } |
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59 | |
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60 | int roar_hash_crc24_init(void * state) { |
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61 | uint32_t * self = state; |
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62 | |
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63 | *self = roar_crc24_init(); |
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64 | |
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65 | return 0; |
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66 | } |
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67 | |
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68 | int roar_hash_crc24_digest(void * state, void * digest, size_t * len) { |
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69 | uint32_t * self = state; |
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70 | unsigned char * out = digest; |
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71 | register uint32_t crc; |
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72 | |
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73 | if ( *len < 3 ) |
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74 | return -1; |
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75 | |
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76 | *len = 3; |
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77 | |
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78 | crc = *self; |
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79 | |
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80 | out[0] = ((crc & 0x00FF0000) >> 16) & 0xFF; |
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81 | out[1] = ((crc & 0x0000FF00) >> 8) & 0xFF; |
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82 | out[2] = ((crc & 0x000000FF) >> 0) & 0xFF; |
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83 | |
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84 | return 0; |
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85 | } |
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86 | |
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87 | int roar_hash_crc24_proc(void * state, const void * data, size_t len) { |
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88 | uint32_t * self = state; |
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89 | |
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90 | *self = roar_crc24_add(*self, data, len); |
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91 | |
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92 | return 0; |
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93 | } |
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94 | |
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95 | //ll |
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