| 1 | /*
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| 2 | * Copyright (c) 2012 Dominik Taborsky
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| 3 | * All rights reserved.
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| 4 | *
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| 5 | * Redistribution and use in source and binary forms, with or without
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| 6 | * modification, are permitted provided that the following conditions
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| 7 | * are met:
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| 8 | *
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| 9 | * - Redistributions of source code must retain the above copyright
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| 10 | * notice, this list of conditions and the following disclaimer.
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| 11 | * - Redistributions in binary form must reproduce the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer in the
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| 13 | * documentation and/or other materials provided with the distribution.
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| 14 | * - The name of the author may not be used to endorse or promote products
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| 15 | * derived from this software without specific prior written permission.
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| 16 | *
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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| 27 | */
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| 28 |
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| 29 | #include <adt/checksum.h>
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| 30 |
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| 31 | /**
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| 32 | * 256-value table of precomputed polynomials for CRC32. Note
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| 33 | * the values depend on the selected divisor polynomial (currently
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| 34 | * 0xedb88320) and whether the CRC computation is reflected or not.
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| 35 | * See http://www.repairfaq.org/filipg/LINK/F_crc_v3.html for a perfect
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| 36 | * source of info about this.
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| 37 | */
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| 38 | uint32_t poly_table[256] = {
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| 39 | 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
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| 40 | 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
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| 41 | 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
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| 42 | 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
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| 43 | 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
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| 44 | 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
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| 45 | 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
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| 46 | 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
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| 47 | 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
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| 48 | 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
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| 49 | 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
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| 50 | 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
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| 51 | 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
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| 52 | 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
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| 53 | 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
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| 54 | 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
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| 55 | 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
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| 56 | 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
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| 57 | 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
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| 58 | 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
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| 59 | 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
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| 60 | 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
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| 61 | 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
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| 62 | 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
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| 63 | 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
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| 64 | 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
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| 65 | 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
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| 66 | 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
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| 67 | 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
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| 68 | 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
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| 69 | 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
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| 70 | 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
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| 71 | 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
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| 72 | 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
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| 73 | 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
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| 74 | 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
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| 75 | 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
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| 76 | 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
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| 77 | 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
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| 78 | 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
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| 79 | 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
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| 80 | 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
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| 81 | 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
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| 82 | 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
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| 83 | 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
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| 84 | 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
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| 85 | 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
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| 86 | 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
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| 87 | 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
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| 88 | 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
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| 89 | 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
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| 90 | 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
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| 91 | 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
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| 92 | 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
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| 93 | 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
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| 94 | 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
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| 95 | 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
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| 96 | 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
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| 97 | 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
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| 98 | 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
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| 99 | 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
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| 100 | 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
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| 101 | 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
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| 102 | 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
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| 103 | };
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| 104 |
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| 105 | /** Compute CRC32 value.
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| 106 | *
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| 107 | * See wiki.osdev.org/CRC32 for reference.
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| 108 | *
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| 109 | * @param[in] data Data to process.
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| 110 | * @param[in] length Length of the data in bytes.
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| 111 | *
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| 112 | * @return Computed CRC32 of the data.
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| 113 | *
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| 114 | */
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| 115 | uint32_t compute_crc32(uint8_t *data, size_t length)
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| 116 | {
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| 117 | return compute_crc32_seed(data, length, 0);
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| 118 | }
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| 119 |
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| 120 | /** Compute CRC32 value with initial seed.
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| 121 | *
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| 122 | * Use this when checksumming non-continous data (linked lists, trees,
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| 123 | * etc.). On the first data block call compute_crc32() and use the result
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| 124 | * as the seed for the following call of compute_crc32_seed() on the next
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| 125 | * block. Then use the result of that call as the seed of the following
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| 126 | * call, etc.
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| 127 | *
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| 128 | * @param[in] data Fata to process.
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| 129 | * @param[in] length Length of the data in bytes.
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| 130 | * @param[in] seed The starting value of the CRC.
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| 131 | *
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| 132 | * @return Computed CRC32 of the data of all the previous blocks.
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| 133 | *
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| 134 | */
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| 135 | uint32_t compute_crc32_seed(uint8_t *data, size_t length, uint32_t seed)
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| 136 | {
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| 137 | uint32_t crc;
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| 138 |
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| 139 | for (crc = ~seed; length > 0; length--)
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| 140 | crc = poly_table[((uint8_t) crc ^ *(data++))] ^ (crc >> 8);
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| 141 |
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| 142 | return (~crc);
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| 143 | }
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| 144 |
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| 145 | /** @}
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| 146 | */
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