嵌入式单片机上的CRC计算和校验程序2
注意：此程序计算出的CRC值，和电脑版CRC计算工具计算出的值相同。
一、CRC32
CRC32的 c程序如下（不需要看，直接看 crc32 函数的使用说明）：
/* * Jan 22, Dortain modifies function for CRC32 of 32 bit-wise * * Aug 8, 2011 Bob Pearson with help from Joakim Tjernlund and George Spelvin * cleaned up code to current version of sparse and added the slicing-by-8 * algorithm to the closely similar existing slicing-by-4 algorithm. * * Oct 15, 2000 Matt Domsch <Matt_Domsch@dell.com> * Nicer crc32 functions/docs submitted by linux@horizon.com. Thanks! * Code was from the public domain, copyright abandoned. Code was * subsequently included in the kernel, thus was re-licensed under the * GNU GPL v2. * * Oct 12, 2000 Matt Domsch <Matt_Domsch@dell.com> * Same crc32 function was used in 5 other places in the kernel. * I made one version, and deleted the others. * There are various incantations of crc32(). Some use a seed of 0 or ~0. * Some xor at the end with ~0. The generic crc32() function takes * seed as an argument, and doesn't xor at the end. Then individual * users can do whatever they need. * drivers/net/smc9194.c uses seed ~0, doesn't xor with ~0. * fs/jffs2 uses seed 0, doesn't xor with ~0. * fs/partitions/efi.c uses seed ~0, xor's with ~0. * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #include <crc32.h> const uint32 crc32table_le[LE_TABLE_ROWS][256] = { {0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7, 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59, 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433, 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65, 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f, 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1, 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b, 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d, 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777, 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9, 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d}, {0x00000000, 0x191b3141, 0x32366282, 0x2b2d53c3, 0x646cc504, 0x7d77f445, 0x565aa786, 0x4f4196c7, 0xc8d98a08, 0xd1c2bb49, 0xfaefe88a, 0xe3f4d9cb, 0xacb54f0c, 0xb5ae7e4d, 0x9e832d8e, 0x87981ccf, 0x4ac21251, 0x53d92310, 0x78f470d3, 0x61ef4192, 0x2eaed755, 0x37b5e614, 0x1c98b5d7, 0x05838496, 0x821b9859, 0x9b00a918, 0xb02dfadb, 0xa936cb9a, 0xe6775d5d, 0xff6c6c1c, 0xd4413fdf, 0xcd5a0e9e, 0x958424a2, 0x8c9f15e3, 0xa7b24620, 0xbea97761, 0xf1e8e1a6, 0xe8f3d0e7, 0xc3de8324, 0xdac5b265, 0x5d5daeaa, 0x44469feb, 0x6f6bcc28, 0x7670fd69, 0x39316bae, 0x202a5aef, 0x0b07092c, 0x121c386d, 0xdf4636f3, 0xc65d07b2, 0xed705471, 0xf46b6530, 0xbb2af3f7, 0xa231c2b6, 0x891c9175, 0x9007a034, 0x179fbcfb, 0x0e848dba, 0x25a9de79, 0x3cb2ef38, 0x73f379ff, 0x6ae848be, 0x41c51b7d, 0x58de2a3c, 0xf0794f05, 0xe9627e44, 0xc24f2d87, 0xdb541cc6, 0x94158a01, 0x8d0ebb40, 0xa623e883, 0xbf38d9c2, 0x38a0c50d, 0x21bbf44c, 0x0a96a78f, 0x138d96ce, 0x5ccc0009, 0x45d73148, 0x6efa628b, 0x77e153ca, 0xbabb5d54, 0xa3a06c15, 0x888d3fd6, 0x91960e97, 0xded79850, 0xc7cca911, 0xece1fad2, 0xf5facb93, 0x7262d75c, 0x6b79e61d, 0x4054b5de, 0x594f849f, 0x160e1258, 0x0f152319, 0x243870da, 0x3d23419b, 0x65fd6ba7, 0x7ce65ae6, 0x57cb0925, 0x4ed03864, 0x0191aea3, 0x188a9fe2, 0x33a7cc21, 0x2abcfd60, 0xad24e1af, 0xb43fd0ee, 0x9f12832d, 0x8609b26c, 0xc94824ab, 0xd05315ea, 0xfb7e4629, 0xe2657768, 0x2f3f79f6, 0x362448b7, 0x1d091b74, 0x04122a35, 0x4b53bcf2, 0x52488db3, 0x7965de70, 0x607eef31, 0xe7e6f3fe, 0xfefdc2bf, 0xd5d0917c, 0xcccba03d, 0x838a36fa, 0x9a9107bb, 0xb1bc5478, 0xa8a76539, 0x3b83984b, 0x2298a90a, 0x09b5fac9, 0x10aecb88, 0x5fef5d4f, 0x46f46c0e, 0x6dd93fcd, 0x74c20e8c, 0xf35a1243, 0xea412302, 0xc16c70c1, 0xd8774180, 0x9736d747, 0x8e2de606, 0xa500b5c5, 0xbc1b8484, 0x71418a1a, 0x685abb5b, 0x4377e898, 0x5a6cd9d9, 0x152d4f1e, 0x0c367e5f, 0x271b2d9c, 0x3e001cdd, 0xb9980012, 0xa0833153, 0x8bae6290, 0x92b553d1, 0xddf4c516, 0xc4eff457, 0xefc2a794, 0xf6d996d5, 0xae07bce9, 0xb71c8da8, 0x9c31de6b, 0x852aef2a, 0xca6b79ed, 0xd37048ac, 0xf85d1b6f, 0xe1462a2e, 0x66de36e1, 0x7fc507a0, 0x54e85463, 0x4df36522, 0x02b2f3e5, 0x1ba9c2a4, 0x30849167, 0x299fa026, 0xe4c5aeb8, 0xfdde9ff9, 0xd6f3cc3a, 0xcfe8fd7b, 0x80a96bbc, 0x99b25afd, 0xb29f093e, 0xab84387f, 0x2c1c24b0, 0x350715f1, 0x1e2a4632, 0x07317773, 0x4870e1b4, 0x516bd0f5, 0x7a468336, 0x635db277, 0xcbfad74e, 0xd2e1e60f, 0xf9ccb5cc, 0xe0d7848d, 0xaf96124a, 0xb68d230b, 0x9da070c8, 0x84bb4189, 0x03235d46, 0x1a386c07, 0x31153fc4, 0x280e0e85, 0x674f9842, 0x7e54a903, 0x5579fac0, 0x4c62cb81, 0x8138c51f, 0x9823f45e, 0xb30ea79d, 0xaa1596dc, 0xe554001b, 0xfc4f315a, 0xd7626299, 0xce7953d8, 0x49e14f17, 0x50fa7e56, 0x7bd72d95, 0x62cc1cd4, 0x2d8d8a13, 0x3496bb52, 0x1fbbe891, 0x06a0d9d0, 0x5e7ef3ec, 0x4765c2ad, 0x6c48916e, 0x7553a02f, 0x3a1236e8, 0x230907a9, 0x0824546a, 0x113f652b, 0x96a779e4, 0x8fbc48a5, 0xa4911b66, 0xbd8a2a27, 0xf2cbbce0, 0xebd08da1, 0xc0fdde62, 0xd9e6ef23, 0x14bce1bd, 0x0da7d0fc, 0x268a833f, 0x3f91b27e, 0x70d024b9, 0x69cb15f8, 0x42e6463b, 0x5bfd777a, 0xdc656bb5, 0xc57e5af4, 0xee530937, 0xf7483876, 0xb809aeb1, 0xa1129ff0, 0x8a3fcc33, 0x9324fd72}, {0x00000000, 0x01c26a37, 0x0384d46e, 0x0246be59, 0x0709a8dc, 0x06cbc2eb, 0x048d7cb2, 0x054f1685, 0x0e1351b8, 0x0fd13b8f, 0x0d9785d6, 0x0c55efe1, 0x091af964, 0x08d89353, 0x0a9e2d0a, 0x0b5c473d, 0x1c26a370, 0x1de4c947, 0x1fa2771e, 0x1e601d29, 0x1b2f0bac, 0x1aed619b, 0x18abdfc2, 0x1969b5f5, 0x1235f2c8, 0x13f798ff, 0x11b126a6, 0x10734c91, 0x153c5a14, 0x14fe3023, 0x16b88e7a, 0x177ae44d, 0x384d46e0, 0x398f2cd7, 0x3bc9928e, 0x3a0bf8b9, 0x3f44ee3c, 0x3e86840b, 0x3cc03a52, 0x3d025065, 0x365e1758, 0x379c7d6f, 0x35dac336, 0x3418a901, 0x3157bf84, 0x3095d5b3, 0x32d36bea, 0x331101dd, 0x246be590, 0x25a98fa7, 0x27ef31fe, 0x262d5bc9, 0x23624d4c, 0x22a0277b, 0x20e69922, 0x2124f315, 0x2a78b428, 0x2bbade1f, 0x29fc6046, 0x283e0a71, 0x2d711cf4, 0x2cb376c3, 0x2ef5c89a, 0x2f37a2ad, 0x709a8dc0, 0x7158e7f7, 0x731e59ae, 0x72dc3399, 0x7793251c, 0x76514f2b, 0x7417f172, 0x75d59b45, 0x7e89dc78, 0x7f4bb64f, 0x7d0d0816, 0x7ccf6221, 0x798074a4, 0x78421e93, 0x7a04a0ca, 0x7bc6cafd, 0x6cbc2eb0, 0x6d7e4487, 0x6f38fade, 0x6efa90e9, 0x6bb5866c, 0x6a77ec5b, 0x68315202, 0x69f33835, 0x62af7f08, 0x636d153f, 0x612bab66, 0x60e9c151, 0x65a6d7d4, 0x6464bde3, 0x662203ba, 0x67e0698d, 0x48d7cb20, 0x4915a117, 0x4b531f4e, 0x4a917579, 0x4fde63fc, 0x4e1c09cb, 0x4c5ab792, 0x4d98dda5, 0x46c49a98, 0x4706f0af, 0x45404ef6, 0x448224c1, 0x41cd3244, 0x400f5873, 0x4249e62a, 0x438b8c1d, 0x54f16850, 0x55330267, 0x5775bc3e, 0x56b7d609, 0x53f8c08c, 0x523aaabb, 0x507c14e2, 0x51be7ed5, 0x5ae239e8, 0x5b2053df, 0x5966ed86, 0x58a487b1, 0x5deb9134, 0x5c29fb03, 0x5e6f455a, 0x5fad2f6d, 0xe1351b80, 0xe0f771b7, 0xe2b1cfee, 0xe373a5d9, 0xe63cb35c, 0xe7fed96b, 0xe5b86732, 0xe47a0d05, 0xef264a38, 0xeee4200f, 0xeca29e56, 0xed60f461, 0xe82fe2e4, 0xe9ed88d3, 0xebab368a, 0xea695cbd, 0xfd13b8f0, 0xfcd1d2c7, 0xfe976c9e, 0xff5506a9, 0xfa1a102c, 0xfbd87a1b, 0xf99ec442, 0xf85cae75, 0xf300e948, 0xf2c2837f, 0xf0843d26, 0xf1465711, 0xf4094194, 0xf5cb2ba3, 0xf78d95fa, 0xf64fffcd, 0xd9785d60, 0xd8ba3757, 0xdafc890e, 0xdb3ee339, 0xde71f5bc, 0xdfb39f8b, 0xddf521d2, 0xdc374be5, 0xd76b0cd8, 0xd6a966ef, 0xd4efd8b6, 0xd52db281, 0xd062a404, 0xd1a0ce33, 0xd3e6706a, 0xd2241a5d, 0xc55efe10, 0xc49c9427, 0xc6da2a7e, 0xc7184049, 0xc25756cc, 0xc3953cfb, 0xc1d382a2, 0xc011e895, 0xcb4dafa8, 0xca8fc59f, 0xc8c97bc6, 0xc90b11f1, 0xcc440774, 0xcd866d43, 0xcfc0d31a, 0xce02b92d, 0x91af9640, 0x906dfc77, 0x922b422e, 0x93e92819, 0x96a63e9c, 0x976454ab, 0x9522eaf2, 0x94e080c5, 0x9fbcc7f8, 0x9e7eadcf, 0x9c381396, 0x9dfa79a1, 0x98b56f24, 0x99770513, 0x9b31bb4a, 0x9af3d17d, 0x8d893530, 0x8c4b5f07, 0x8e0de15e, 0x8fcf8b69, 0x8a809dec, 0x8b42f7db, 0x89044982, 0x88c623b5, 0x839a6488, 0x82580ebf, 0x801eb0e6, 0x81dcdad1, 0x8493cc54, 0x8551a663, 0x8717183a, 0x86d5720d, 0xa9e2d0a0, 0xa820ba97, 0xaa6604ce, 0xaba46ef9, 0xaeeb787c, 0xaf29124b, 0xad6fac12, 0xacadc625, 0xa7f18118, 0xa633eb2f, 0xa4755576, 0xa5b73f41, 0xa0f829c4, 0xa13a43f3, 0xa37cfdaa, 0xa2be979d, 0xb5c473d0, 0xb40619e7, 0xb640a7be, 0xb782cd89, 0xb2cddb0c, 0xb30fb13b, 0xb1490f62, 0xb08b6555, 0xbbd72268, 0xba15485f, 0xb853f606, 0xb9919c31, 0xbcde8ab4, 0xbd1ce083, 0xbf5a5eda, 0xbe9834ed}, {0x00000000, 0xb8bc6765, 0xaa09c88b, 0x12b5afee, 0x8f629757, 0x37def032, 0x256b5fdc, 0x9dd738b9, 0xc5b428ef, 0x7d084f8a, 0x6fbde064, 0xd7018701, 0x4ad6bfb8, 0xf26ad8dd, 0xe0df7733, 0x58631056, 0x5019579f, 0xe8a530fa, 0xfa109f14, 0x42acf871, 0xdf7bc0c8, 0x67c7a7ad, 0x75720843, 0xcdce6f26, 0x95ad7f70, 0x2d111815, 0x3fa4b7fb, 0x8718d09e, 0x1acfe827, 0xa2738f42, 0xb0c620ac, 0x087a47c9, 0xa032af3e, 0x188ec85b, 0x0a3b67b5, 0xb28700d0, 0x2f503869, 0x97ec5f0c, 0x8559f0e2, 0x3de59787, 0x658687d1, 0xdd3ae0b4, 0xcf8f4f5a, 0x7733283f, 0xeae41086, 0x525877e3, 0x40edd80d, 0xf851bf68, 0xf02bf8a1, 0x48979fc4, 0x5a22302a, 0xe29e574f, 0x7f496ff6, 0xc7f50893, 0xd540a77d, 0x6dfcc018, 0x359fd04e, 0x8d23b72b, 0x9f9618c5, 0x272a7fa0, 0xbafd4719, 0x0241207c, 0x10f48f92, 0xa848e8f7, 0x9b14583d, 0x23a83f58, 0x311d90b6, 0x89a1f7d3, 0x1476cf6a, 0xaccaa80f, 0xbe7f07e1, 0x06c36084, 0x5ea070d2, 0xe61c17b7, 0xf4a9b859, 0x4c15df3c, 0xd1c2e785, 0x697e80e0, 0x7bcb2f0e, 0xc377486b, 0xcb0d0fa2, 0x73b168c7, 0x6104c729, 0xd9b8a04c, 0x446f98f5, 0xfcd3ff90, 0xee66507e, 0x56da371b, 0x0eb9274d, 0xb6054028, 0xa4b0efc6, 0x1c0c88a3, 0x81dbb01a, 0x3967d77f, 0x2bd27891, 0x936e1ff4, 0x3b26f703, 0x839a9066, 0x912f3f88, 0x299358ed, 0xb4446054, 0x0cf80731, 0x1e4da8df, 0xa6f1cfba, 0xfe92dfec, 0x462eb889, 0x549b1767, 0xec277002, 0x71f048bb, 0xc94c2fde, 0xdbf98030, 0x6345e755, 0x6b3fa09c, 0xd383c7f9, 0xc1366817, 0x798a0f72, 0xe45d37cb, 0x5ce150ae, 0x4e54ff40, 0xf6e89825, 0xae8b8873, 0x1637ef16, 0x048240f8, 0xbc3e279d, 0x21e91f24, 0x99557841, 0x8be0d7af, 0x335cb0ca, 0xed59b63b, 0x55e5d15e, 0x47507eb0, 0xffec19d5, 0x623b216c, 0xda874609, 0xc832e9e7, 0x708e8e82, 0x28ed9ed4, 0x9051f9b1, 0x82e4565f, 0x3a58313a, 0xa78f0983, 0x1f336ee6, 0x0d86c108, 0xb53aa66d, 0xbd40e1a4, 0x05fc86c1, 0x1749292f, 0xaff54e4a, 0x322276f3, 0x8a9e1196, 0x982bbe78, 0x2097d91d, 0x78f4c94b, 0xc048ae2e, 0xd2fd01c0, 0x6a4166a5, 0xf7965e1c, 0x4f2a3979, 0x5d9f9697, 0xe523f1f2, 0x4d6b1905, 0xf5d77e60, 0xe762d18e, 0x5fdeb6eb, 0xc2098e52, 0x7ab5e937, 0x680046d9, 0xd0bc21bc, 0x88df31ea, 0x3063568f, 0x22d6f961, 0x9a6a9e04, 0x07bda6bd, 0xbf01c1d8, 0xadb46e36, 0x15080953, 0x1d724e9a, 0xa5ce29ff, 0xb77b8611, 0x0fc7e174, 0x9210d9cd, 0x2aacbea8, 0x38191146, 0x80a57623, 0xd8c66675, 0x607a0110, 0x72cfaefe, 0xca73c99b, 0x57a4f122, 0xef189647, 0xfdad39a9, 0x45115ecc, 0x764dee06, 0xcef18963, 0xdc44268d, 0x64f841e8, 0xf92f7951, 0x41931e34, 0x5326b1da, 0xeb9ad6bf, 0xb3f9c6e9, 0x0b45a18c, 0x19f00e62, 0xa14c6907, 0x3c9b51be, 0x842736db, 0x96929935, 0x2e2efe50, 0x2654b999, 0x9ee8defc, 0x8c5d7112, 0x34e11677, 0xa9362ece, 0x118a49ab, 0x033fe645, 0xbb838120, 0xe3e09176, 0x5b5cf613, 0x49e959fd, 0xf1553e98, 0x6c820621, 0xd43e6144, 0xc68bceaa, 0x7e37a9cf, 0xd67f4138, 0x6ec3265d, 0x7c7689b3, 0xc4caeed6, 0x591dd66f, 0xe1a1b10a, 0xf3141ee4, 0x4ba87981, 0x13cb69d7, 0xab770eb2, 0xb9c2a15c, 0x017ec639, 0x9ca9fe80, 0x241599e5, 0x36a0360b, 0x8e1c516e, 0x866616a7, 0x3eda71c2, 0x2c6fde2c, 0x94d3b949, 0x090481f0, 0xb1b8e695, 0xa30d497b, 0x1bb12e1e, 0x43d23e48, 0xfb6e592d, 0xe9dbf6c3, 0x516791a6, 0xccb0a91f, 0x740cce7a, 0x66b96194, 0xde0506f1}}; /* crc32init_be() - allocate and initialize BE table data */ #ifndef LITTLE_ENDIAN static void crc32init_be_generic(const uint32 polynomial, uint32 (*tab)[256]) { uint32 i, j; uint32 crc = 0x80000000; for (i = 1; i < BE_TABLE_SIZE; i <<= 1) { crc = (crc << 1) ^ ((crc & 0x80000000) ? CRCPOLY_BE : 0); for (j = 0; j < i; j++) tab[0][i + j] = crc ^ tab[0][j]; } for (i = 0; i < BE_TABLE_SIZE; i++) { crc = tab[0][i]; for (j = 1; j < BE_TABLE_ROWS; j++) { crc = tab[0][(crc >> 24) & 0xff] ^ (crc << 8); tab[j][i] = crc; } } } #endif /* implements slicing-by-4 algorithm */ static inline uint32 crc32_body(uint32 crc, const uint8 *buf, uint32 len, const uint32 (*tab)[256]) { # ifdef LITTLE_ENDIAN # define DO_CRC(x) crc = t0[(crc ^ (x)) & 255] ^ (crc >> 8) # define DO_CRC4 (t3[(q) & 255] ^ t2[(q >> 8) & 255] ^ \ t1[(q >> 16) & 255] ^ t0[(q >> 24) & 255]) # else # define DO_CRC(x) crc = t0[((crc >> 24) ^ (x)) & 255] ^ (crc << 8) # define DO_CRC4 (t0[(q) & 255] ^ t1[(q >> 8) & 255] ^ \ t2[(q >> 16) & 255] ^ t3[(q >> 24) & 255]) # endif const uint32 *b; uint32 rem_len; uint32 i; uint32 q; const uint32 *t0 = tab[0], *t1 = tab[1], *t2 = tab[2], *t3 = tab[3]; /* Make sure that the buf addr is multiples of 4 */ if (((uint32)buf & 3) && len) { do { DO_CRC(*buf++); } while ((--len) && (((uint32)buf) & 3)); } rem_len = len & 3; len = len >> 2; b = (const uint32 *)buf; --b; for (i = 0; i < len; i++) { q = crc ^ *++b; // use pre increment for speed crc = DO_CRC4; } len = rem_len; /* And the last few bytes */ if (len) { uint8 *p = (uint8 *)(b + 1) - 1; for (i = 0; i < len; i++) DO_CRC(*++p); // use pre increment for speed } return crc; #undef DO_CRC #undef DO_CRC4 } /** * crc32_le_generic() - Calculate bitwise little-endian Ethernet AUTODIN II * CRC32/CRC32C * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for other * uses, or the previous crc32/crc32c value if computing incrementally. * @p: pointer to buffer over which CRC32/CRC32C is run * @len: length of buffer @p * @tab: little-endian Ethernet table * @polynomial: CRC32/CRC32c LE polynomial */ static inline uint32 crc32_le_generic(uint32 crc, const uint8 *p, uint32 len, const uint32 (*tab)[256], uint32 polynomial) { crc = crc32_body(crc, p, len, tab); return crc; } uint32 crc32_le(uint32 crc, const uint8 *p, uint32 len) { return crc32_le_generic(crc, p, len, crc32table_le, CRCPOLY_LE); } /** * crc32_be_generic() - Calculate bitwise big-endian Ethernet AUTODIN II CRC32 * @crc: seed value for computation. ~0 for Ethernet, sometimes 0 for * other uses, or the previous crc32 value if computing incrementally. * @p: pointer to buffer over which CRC32 is run * @len: length of buffer @p * @tab: big-endian Ethernet table * @polynomial: CRC32 BE polynomial */ #ifndef LITTLE_ENDIAN static inline uint32 crc32_be_generic(uint32 crc, const uint8 *p, uint32 len, uint32 (*tab)[256], uint32 polynomial) { crc = crc32_body(crc, p, len, tab); return crc; } uint32 crc32_be(uint32 crc, const uint8 *p, uint32 len) { uint32 crc32table_be[BE_TABLE_ROWS][256]; crc32init_be_generic(CRCPOLY_BE, crc32table_be); return crc32_be_generic(crc, p, len, crc32table_be, CRCPOLY_BE); } #endif
CRC32的 .h程序如下（不需要看，直接看 crc32 函数的使用说明）：
#ifndef __CRC32_H__ #define __CRC32_H__ #include <sysdep.h> /** * Note: * Select endian mode in case of machine endian type * * little endian: ARM(default), X86,... * big endian: PowerPC, KEIL C51, network * */ #define LITTLE_ENDIAN /** * There are multiple 16-bit CRC polynomials in common use, but this is * *the* standard CRC-32 polynomial, first popularized by Ethernet. * x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x^1+x^0 */ #define CRCPOLY_LE 0xedb88320 #define CRCPOLY_BE 0x04c11db7 /** * How many bits at a time to use. Valid values are 1, 2, 4, 8, 32 and 64. * For less performance-sensitive, use 4 or 8 to save table size. * For larger systems choose same as CPU architecture as default. */ #ifndef CRC_LE_BITS # define CRC_LE_BITS 32 #endif #ifndef CRC_BE_BITS # define CRC_BE_BITS 32 #endif #if CRC_LE_BITS > 8 # define LE_TABLE_ROWS (CRC_LE_BITS/8) # define LE_TABLE_SIZE 256 #endif #if CRC_BE_BITS > 8 # define BE_TABLE_ROWS (CRC_BE_BITS/8) # define BE_TABLE_SIZE 256 #endif /** * For CRC32, need table size using stack about 256*4*4 = 4KB * * For test and checking, we can generate CRC32 using WinRAR software mode * We suggest that: * seed = ~0; * crc32 = crc32(seed, data, length) ^ (~0); * return crc32; */ #ifdef LITTLE_ENDIAN uint32 crc32_le(uint32 crc, const uint8 *p, uint32 len); #define crc32(seed, pbuf, length) crc32_le(seed, (const uint8 *)(pbuf), length) #else uint32 crc32_be(uint32 crc, const uint8 *p, uint32 len); #define crc32(seed, pbuf, length) crc32_be(seed, (const uint8 *)(pbuf), length) #endif #endif /* __CRC32_H__ */
根据注释：
可知crc32 函数的使用说明:
假设有数据a[10] = {0xAA, 0x15, 0x00, 0x00, 0x55, 0x88, 0x00, 0x00, 0x66, 0xFF}， 计算这10个字节的CRC32的值。
其CRC32的值是 crc32(0xFFFFFFFF, (uint8 *)a, 10) ^ 0xFFFFFFFF
二、CRC16
CRC16的 c程序如下（不需要看，直接看 crc16 函数的使用说明）：
/* * crc16.c * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. * * modified by Dortain */ #include <crc16.h> /** CRC table for the CRC ITU-T V.41 0x1021 (x^16 + x^12 + x^15 + 1) */ const uint16 crc_itu_t_table[256] = { 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7, 0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef, 0x1231, 0x0210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6, 0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de, 0x2462, 0x3443, 0x0420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485, 0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d, 0x3653, 0x2672, 0x1611, 0x0630, 0x76d7, 0x66f6, 0x5695, 0x46b4, 0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc, 0x48c4, 0x58e5, 0x6886, 0x78a7, 0x0840, 0x1861, 0x2802, 0x3823, 0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b, 0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0x0a50, 0x3a33, 0x2a12, 0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a, 0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0x0c60, 0x1c41, 0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49, 0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0x0e70, 0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78, 0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f, 0x1080, 0x00a1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067, 0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e, 0x02b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256, 0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d, 0x34e2, 0x24c3, 0x14a0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c, 0x26d3, 0x36f2, 0x0691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634, 0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab, 0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x08e1, 0x3882, 0x28a3, 0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a, 0x4a75, 0x5a54, 0x6a37, 0x7a16, 0x0af1, 0x1ad0, 0x2ab3, 0x3a92, 0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9, 0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0x0cc1, 0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8, 0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0x0ed1, 0x1ef0 }; static inline uint16 crc_itu_t_byte(uint16 crc, const uint8 data) { return ((crc << 8) ^ crc_itu_t_table[((crc >> 8) ^ data) & 0xff]); } /** * crc_itu_t - Compute the CRC-ITU-T for the data buffer * * @crc: previous CRC value * @buffer: data pointer * @len: number of bytes in the buffer * * Returns the updated CRC value */ uint16 crc16_itu_t(uint16 seed, const uint8 *buffer, uint32 len) { uint16 crc; crc = seed; while (len--) { crc = crc_itu_t_byte(crc, *buffer++); } return crc; }
CRC16的 .h程序如下（不需要看，直接看 crc16 函数的使用说明）：
/** * crc16.h * * Implements the standard CRC ITU-T V.41: * Width 16 * Poly 0x1021 (x^16 + x^12 + x^15 + 1) * Init 0 * * This source code is licensed under the GNU General Public License, * Version 2. See the file COPYING for more details. */ #ifndef __CRC16_H__ #define __CRC16_H__ #include <sysdep.h> /** * For CRC16, need table size using RO data section about 256*2 = 512B * * CRC-itu-t/CRC16 is a standard used by XMODEM/ZMODEM communication * * For checking, we can generate CRC16 like XMODEM software mode * * We suggest that: * seed = 0; * crc16 = crc16_itu_t(seed, buffer, length); * return crc16; */ uint16 crc16_itu_t(uint16 seed, const uint8 *buffer, uint32 len); #define crc16(seed, pbuf, length) crc16_itu_t(seed, (const uint8 *)pbuf, length) #endif /* __CRC16_H__ */
根据注释：
可知crc16 函数的使用说明:
假设有数据a[10] = {0xAA, 0x15, 0x00, 0x00, 0x55, 0x88, 0x00, 0x00, 0x66, 0xFF}， 计算这10个字节的CRC16的值。
其CRC16的值是 crc16(0, (uint8 *)a, 10)
