Botan  2.6.0
Crypto and TLS for C++11
crc24.cpp
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1 /*
2 * CRC24
3 * (C) 1999-2007 Jack Lloyd
4 * (C) 2017 [Ribose Inc](https://www.ribose.com). Performed by Krzysztof Kwiatkowski.
5 *
6 * Botan is released under the Simplified BSD License (see license.txt)
7 */
8 
9 #include <botan/crc24.h>
10 #include <botan/loadstor.h>
11 #include <botan/bswap.h>
12 
13 namespace Botan {
14 
15 namespace {
16 
17 const uint32_t CRC24_T0[256] = {
18  0x00000000, 0x00FB4C86, 0x000DD58A, 0x00F6990C, 0x00E1E693, 0x001AAA15, 0x00EC3319,
19  0x00177F9F, 0x003981A1, 0x00C2CD27, 0x0034542B, 0x00CF18AD, 0x00D86732, 0x00232BB4,
20  0x00D5B2B8, 0x002EFE3E, 0x00894EC5, 0x00720243, 0x00849B4F, 0x007FD7C9, 0x0068A856,
21  0x0093E4D0, 0x00657DDC, 0x009E315A, 0x00B0CF64, 0x004B83E2, 0x00BD1AEE, 0x00465668,
22  0x005129F7, 0x00AA6571, 0x005CFC7D, 0x00A7B0FB, 0x00E9D10C, 0x00129D8A, 0x00E40486,
23  0x001F4800, 0x0008379F, 0x00F37B19, 0x0005E215, 0x00FEAE93, 0x00D050AD, 0x002B1C2B,
24  0x00DD8527, 0x0026C9A1, 0x0031B63E, 0x00CAFAB8, 0x003C63B4, 0x00C72F32, 0x00609FC9,
25  0x009BD34F, 0x006D4A43, 0x009606C5, 0x0081795A, 0x007A35DC, 0x008CACD0, 0x0077E056,
26  0x00591E68, 0x00A252EE, 0x0054CBE2, 0x00AF8764, 0x00B8F8FB, 0x0043B47D, 0x00B52D71,
27  0x004E61F7, 0x00D2A319, 0x0029EF9F, 0x00DF7693, 0x00243A15, 0x0033458A, 0x00C8090C,
28  0x003E9000, 0x00C5DC86, 0x00EB22B8, 0x00106E3E, 0x00E6F732, 0x001DBBB4, 0x000AC42B,
29  0x00F188AD, 0x000711A1, 0x00FC5D27, 0x005BEDDC, 0x00A0A15A, 0x00563856, 0x00AD74D0,
30  0x00BA0B4F, 0x004147C9, 0x00B7DEC5, 0x004C9243, 0x00626C7D, 0x009920FB, 0x006FB9F7,
31  0x0094F571, 0x00838AEE, 0x0078C668, 0x008E5F64, 0x007513E2, 0x003B7215, 0x00C03E93,
32  0x0036A79F, 0x00CDEB19, 0x00DA9486, 0x0021D800, 0x00D7410C, 0x002C0D8A, 0x0002F3B4,
33  0x00F9BF32, 0x000F263E, 0x00F46AB8, 0x00E31527, 0x001859A1, 0x00EEC0AD, 0x00158C2B,
34  0x00B23CD0, 0x00497056, 0x00BFE95A, 0x0044A5DC, 0x0053DA43, 0x00A896C5, 0x005E0FC9,
35  0x00A5434F, 0x008BBD71, 0x0070F1F7, 0x008668FB, 0x007D247D, 0x006A5BE2, 0x00911764,
36  0x00678E68, 0x009CC2EE, 0x00A44733, 0x005F0BB5, 0x00A992B9, 0x0052DE3F, 0x0045A1A0,
37  0x00BEED26, 0x0048742A, 0x00B338AC, 0x009DC692, 0x00668A14, 0x00901318, 0x006B5F9E,
38  0x007C2001, 0x00876C87, 0x0071F58B, 0x008AB90D, 0x002D09F6, 0x00D64570, 0x0020DC7C,
39  0x00DB90FA, 0x00CCEF65, 0x0037A3E3, 0x00C13AEF, 0x003A7669, 0x00148857, 0x00EFC4D1,
40  0x00195DDD, 0x00E2115B, 0x00F56EC4, 0x000E2242, 0x00F8BB4E, 0x0003F7C8, 0x004D963F,
41  0x00B6DAB9, 0x004043B5, 0x00BB0F33, 0x00AC70AC, 0x00573C2A, 0x00A1A526, 0x005AE9A0,
42  0x0074179E, 0x008F5B18, 0x0079C214, 0x00828E92, 0x0095F10D, 0x006EBD8B, 0x00982487,
43  0x00636801, 0x00C4D8FA, 0x003F947C, 0x00C90D70, 0x003241F6, 0x00253E69, 0x00DE72EF,
44  0x0028EBE3, 0x00D3A765, 0x00FD595B, 0x000615DD, 0x00F08CD1, 0x000BC057, 0x001CBFC8,
45  0x00E7F34E, 0x00116A42, 0x00EA26C4, 0x0076E42A, 0x008DA8AC, 0x007B31A0, 0x00807D26,
46  0x009702B9, 0x006C4E3F, 0x009AD733, 0x00619BB5, 0x004F658B, 0x00B4290D, 0x0042B001,
47  0x00B9FC87, 0x00AE8318, 0x0055CF9E, 0x00A35692, 0x00581A14, 0x00FFAAEF, 0x0004E669,
48  0x00F27F65, 0x000933E3, 0x001E4C7C, 0x00E500FA, 0x001399F6, 0x00E8D570, 0x00C62B4E,
49  0x003D67C8, 0x00CBFEC4, 0x0030B242, 0x0027CDDD, 0x00DC815B, 0x002A1857, 0x00D154D1,
50  0x009F3526, 0x006479A0, 0x0092E0AC, 0x0069AC2A, 0x007ED3B5, 0x00859F33, 0x0073063F,
51  0x00884AB9, 0x00A6B487, 0x005DF801, 0x00AB610D, 0x00502D8B, 0x00475214, 0x00BC1E92,
52  0x004A879E, 0x00B1CB18, 0x00167BE3, 0x00ED3765, 0x001BAE69, 0x00E0E2EF, 0x00F79D70,
53  0x000CD1F6, 0x00FA48FA, 0x0001047C, 0x002FFA42, 0x00D4B6C4, 0x00222FC8, 0x00D9634E,
54  0x00CE1CD1, 0x00355057, 0x00C3C95B, 0x003885DD };
55 
56 const uint32_t CRC24_T1[256] = {
57  0x00000000, 0x00488F66, 0x00901ECD, 0x00D891AB, 0x00DB711C, 0x0093FE7A, 0x004B6FD1,
58  0x0003E0B7, 0x00B6E338, 0x00FE6C5E, 0x0026FDF5, 0x006E7293, 0x006D9224, 0x00251D42,
59  0x00FD8CE9, 0x00B5038F, 0x006CC771, 0x00244817, 0x00FCD9BC, 0x00B456DA, 0x00B7B66D,
60  0x00FF390B, 0x0027A8A0, 0x006F27C6, 0x00DA2449, 0x0092AB2F, 0x004A3A84, 0x0002B5E2,
61  0x00015555, 0x0049DA33, 0x00914B98, 0x00D9C4FE, 0x00D88EE3, 0x00900185, 0x0048902E,
62  0x00001F48, 0x0003FFFF, 0x004B7099, 0x0093E132, 0x00DB6E54, 0x006E6DDB, 0x0026E2BD,
63  0x00FE7316, 0x00B6FC70, 0x00B51CC7, 0x00FD93A1, 0x0025020A, 0x006D8D6C, 0x00B44992,
64  0x00FCC6F4, 0x0024575F, 0x006CD839, 0x006F388E, 0x0027B7E8, 0x00FF2643, 0x00B7A925,
65  0x0002AAAA, 0x004A25CC, 0x0092B467, 0x00DA3B01, 0x00D9DBB6, 0x009154D0, 0x0049C57B,
66  0x00014A1D, 0x004B5141, 0x0003DE27, 0x00DB4F8C, 0x0093C0EA, 0x0090205D, 0x00D8AF3B,
67  0x00003E90, 0x0048B1F6, 0x00FDB279, 0x00B53D1F, 0x006DACB4, 0x002523D2, 0x0026C365,
68  0x006E4C03, 0x00B6DDA8, 0x00FE52CE, 0x00279630, 0x006F1956, 0x00B788FD, 0x00FF079B,
69  0x00FCE72C, 0x00B4684A, 0x006CF9E1, 0x00247687, 0x00917508, 0x00D9FA6E, 0x00016BC5,
70  0x0049E4A3, 0x004A0414, 0x00028B72, 0x00DA1AD9, 0x009295BF, 0x0093DFA2, 0x00DB50C4,
71  0x0003C16F, 0x004B4E09, 0x0048AEBE, 0x000021D8, 0x00D8B073, 0x00903F15, 0x00253C9A,
72  0x006DB3FC, 0x00B52257, 0x00FDAD31, 0x00FE4D86, 0x00B6C2E0, 0x006E534B, 0x0026DC2D,
73  0x00FF18D3, 0x00B797B5, 0x006F061E, 0x00278978, 0x002469CF, 0x006CE6A9, 0x00B47702,
74  0x00FCF864, 0x0049FBEB, 0x0001748D, 0x00D9E526, 0x00916A40, 0x00928AF7, 0x00DA0591,
75  0x0002943A, 0x004A1B5C, 0x0096A282, 0x00DE2DE4, 0x0006BC4F, 0x004E3329, 0x004DD39E,
76  0x00055CF8, 0x00DDCD53, 0x00954235, 0x002041BA, 0x0068CEDC, 0x00B05F77, 0x00F8D011,
77  0x00FB30A6, 0x00B3BFC0, 0x006B2E6B, 0x0023A10D, 0x00FA65F3, 0x00B2EA95, 0x006A7B3E,
78  0x0022F458, 0x002114EF, 0x00699B89, 0x00B10A22, 0x00F98544, 0x004C86CB, 0x000409AD,
79  0x00DC9806, 0x00941760, 0x0097F7D7, 0x00DF78B1, 0x0007E91A, 0x004F667C, 0x004E2C61,
80  0x0006A307, 0x00DE32AC, 0x0096BDCA, 0x00955D7D, 0x00DDD21B, 0x000543B0, 0x004DCCD6,
81  0x00F8CF59, 0x00B0403F, 0x0068D194, 0x00205EF2, 0x0023BE45, 0x006B3123, 0x00B3A088,
82  0x00FB2FEE, 0x0022EB10, 0x006A6476, 0x00B2F5DD, 0x00FA7ABB, 0x00F99A0C, 0x00B1156A,
83  0x006984C1, 0x00210BA7, 0x00940828, 0x00DC874E, 0x000416E5, 0x004C9983, 0x004F7934,
84  0x0007F652, 0x00DF67F9, 0x0097E89F, 0x00DDF3C3, 0x00957CA5, 0x004DED0E, 0x00056268,
85  0x000682DF, 0x004E0DB9, 0x00969C12, 0x00DE1374, 0x006B10FB, 0x00239F9D, 0x00FB0E36,
86  0x00B38150, 0x00B061E7, 0x00F8EE81, 0x00207F2A, 0x0068F04C, 0x00B134B2, 0x00F9BBD4,
87  0x00212A7F, 0x0069A519, 0x006A45AE, 0x0022CAC8, 0x00FA5B63, 0x00B2D405, 0x0007D78A,
88  0x004F58EC, 0x0097C947, 0x00DF4621, 0x00DCA696, 0x009429F0, 0x004CB85B, 0x0004373D,
89  0x00057D20, 0x004DF246, 0x009563ED, 0x00DDEC8B, 0x00DE0C3C, 0x0096835A, 0x004E12F1,
90  0x00069D97, 0x00B39E18, 0x00FB117E, 0x002380D5, 0x006B0FB3, 0x0068EF04, 0x00206062,
91  0x00F8F1C9, 0x00B07EAF, 0x0069BA51, 0x00213537, 0x00F9A49C, 0x00B12BFA, 0x00B2CB4D,
92  0x00FA442B, 0x0022D580, 0x006A5AE6, 0x00DF5969, 0x0097D60F, 0x004F47A4, 0x0007C8C2,
93  0x00042875, 0x004CA713, 0x009436B8, 0x00DCB9DE };
94 
95 const uint32_t CRC24_T2[256] = {
96  0x00000000, 0x00D70983, 0x00555F80, 0x00825603, 0x0051F286, 0x0086FB05, 0x0004AD06,
97  0x00D3A485, 0x0059A88B, 0x008EA108, 0x000CF70B, 0x00DBFE88, 0x00085A0D, 0x00DF538E,
98  0x005D058D, 0x008A0C0E, 0x00491C91, 0x009E1512, 0x001C4311, 0x00CB4A92, 0x0018EE17,
99  0x00CFE794, 0x004DB197, 0x009AB814, 0x0010B41A, 0x00C7BD99, 0x0045EB9A, 0x0092E219,
100  0x0041469C, 0x00964F1F, 0x0014191C, 0x00C3109F, 0x006974A4, 0x00BE7D27, 0x003C2B24,
101  0x00EB22A7, 0x00388622, 0x00EF8FA1, 0x006DD9A2, 0x00BAD021, 0x0030DC2F, 0x00E7D5AC,
102  0x006583AF, 0x00B28A2C, 0x00612EA9, 0x00B6272A, 0x00347129, 0x00E378AA, 0x00206835,
103  0x00F761B6, 0x007537B5, 0x00A23E36, 0x00719AB3, 0x00A69330, 0x0024C533, 0x00F3CCB0,
104  0x0079C0BE, 0x00AEC93D, 0x002C9F3E, 0x00FB96BD, 0x00283238, 0x00FF3BBB, 0x007D6DB8,
105  0x00AA643B, 0x0029A4CE, 0x00FEAD4D, 0x007CFB4E, 0x00ABF2CD, 0x00785648, 0x00AF5FCB,
106  0x002D09C8, 0x00FA004B, 0x00700C45, 0x00A705C6, 0x002553C5, 0x00F25A46, 0x0021FEC3,
107  0x00F6F740, 0x0074A143, 0x00A3A8C0, 0x0060B85F, 0x00B7B1DC, 0x0035E7DF, 0x00E2EE5C,
108  0x00314AD9, 0x00E6435A, 0x00641559, 0x00B31CDA, 0x003910D4, 0x00EE1957, 0x006C4F54,
109  0x00BB46D7, 0x0068E252, 0x00BFEBD1, 0x003DBDD2, 0x00EAB451, 0x0040D06A, 0x0097D9E9,
110  0x00158FEA, 0x00C28669, 0x001122EC, 0x00C62B6F, 0x00447D6C, 0x009374EF, 0x001978E1,
111  0x00CE7162, 0x004C2761, 0x009B2EE2, 0x00488A67, 0x009F83E4, 0x001DD5E7, 0x00CADC64,
112  0x0009CCFB, 0x00DEC578, 0x005C937B, 0x008B9AF8, 0x00583E7D, 0x008F37FE, 0x000D61FD,
113  0x00DA687E, 0x00506470, 0x00876DF3, 0x00053BF0, 0x00D23273, 0x000196F6, 0x00D69F75,
114  0x0054C976, 0x0083C0F5, 0x00A9041B, 0x007E0D98, 0x00FC5B9B, 0x002B5218, 0x00F8F69D,
115  0x002FFF1E, 0x00ADA91D, 0x007AA09E, 0x00F0AC90, 0x0027A513, 0x00A5F310, 0x0072FA93,
116  0x00A15E16, 0x00765795, 0x00F40196, 0x00230815, 0x00E0188A, 0x00371109, 0x00B5470A,
117  0x00624E89, 0x00B1EA0C, 0x0066E38F, 0x00E4B58C, 0x0033BC0F, 0x00B9B001, 0x006EB982,
118  0x00ECEF81, 0x003BE602, 0x00E84287, 0x003F4B04, 0x00BD1D07, 0x006A1484, 0x00C070BF,
119  0x0017793C, 0x00952F3F, 0x004226BC, 0x00918239, 0x00468BBA, 0x00C4DDB9, 0x0013D43A,
120  0x0099D834, 0x004ED1B7, 0x00CC87B4, 0x001B8E37, 0x00C82AB2, 0x001F2331, 0x009D7532,
121  0x004A7CB1, 0x00896C2E, 0x005E65AD, 0x00DC33AE, 0x000B3A2D, 0x00D89EA8, 0x000F972B,
122  0x008DC128, 0x005AC8AB, 0x00D0C4A5, 0x0007CD26, 0x00859B25, 0x005292A6, 0x00813623,
123  0x00563FA0, 0x00D469A3, 0x00036020, 0x0080A0D5, 0x0057A956, 0x00D5FF55, 0x0002F6D6,
124  0x00D15253, 0x00065BD0, 0x00840DD3, 0x00530450, 0x00D9085E, 0x000E01DD, 0x008C57DE,
125  0x005B5E5D, 0x0088FAD8, 0x005FF35B, 0x00DDA558, 0x000AACDB, 0x00C9BC44, 0x001EB5C7,
126  0x009CE3C4, 0x004BEA47, 0x00984EC2, 0x004F4741, 0x00CD1142, 0x001A18C1, 0x009014CF,
127  0x00471D4C, 0x00C54B4F, 0x001242CC, 0x00C1E649, 0x0016EFCA, 0x0094B9C9, 0x0043B04A,
128  0x00E9D471, 0x003EDDF2, 0x00BC8BF1, 0x006B8272, 0x00B826F7, 0x006F2F74, 0x00ED7977,
129  0x003A70F4, 0x00B07CFA, 0x00677579, 0x00E5237A, 0x00322AF9, 0x00E18E7C, 0x003687FF,
130  0x00B4D1FC, 0x0063D87F, 0x00A0C8E0, 0x0077C163, 0x00F59760, 0x00229EE3, 0x00F13A66,
131  0x002633E5, 0x00A465E6, 0x00736C65, 0x00F9606B, 0x002E69E8, 0x00AC3FEB, 0x007B3668,
132  0x00A892ED, 0x007F9B6E, 0x00FDCD6D, 0x002AC4EE };
133 
134 const uint32_t CRC24_T3[256] = {
135  0x00000000, 0x00520936, 0x00A4126C, 0x00F61B5A, 0x004825D8, 0x001A2CEE, 0x00EC37B4,
136  0x00BE3E82, 0x006B0636, 0x00390F00, 0x00CF145A, 0x009D1D6C, 0x002323EE, 0x00712AD8,
137  0x00873182, 0x00D538B4, 0x00D60C6C, 0x0084055A, 0x00721E00, 0x00201736, 0x009E29B4,
138  0x00CC2082, 0x003A3BD8, 0x006832EE, 0x00BD0A5A, 0x00EF036C, 0x00191836, 0x004B1100,
139  0x00F52F82, 0x00A726B4, 0x00513DEE, 0x000334D8, 0x00AC19D8, 0x00FE10EE, 0x00080BB4,
140  0x005A0282, 0x00E43C00, 0x00B63536, 0x00402E6C, 0x0012275A, 0x00C71FEE, 0x009516D8,
141  0x00630D82, 0x003104B4, 0x008F3A36, 0x00DD3300, 0x002B285A, 0x0079216C, 0x007A15B4,
142  0x00281C82, 0x00DE07D8, 0x008C0EEE, 0x0032306C, 0x0060395A, 0x00962200, 0x00C42B36,
143  0x00111382, 0x00431AB4, 0x00B501EE, 0x00E708D8, 0x0059365A, 0x000B3F6C, 0x00FD2436,
144  0x00AF2D00, 0x00A37F36, 0x00F17600, 0x00076D5A, 0x0055646C, 0x00EB5AEE, 0x00B953D8,
145  0x004F4882, 0x001D41B4, 0x00C87900, 0x009A7036, 0x006C6B6C, 0x003E625A, 0x00805CD8,
146  0x00D255EE, 0x00244EB4, 0x00764782, 0x0075735A, 0x00277A6C, 0x00D16136, 0x00836800,
147  0x003D5682, 0x006F5FB4, 0x009944EE, 0x00CB4DD8, 0x001E756C, 0x004C7C5A, 0x00BA6700,
148  0x00E86E36, 0x005650B4, 0x00045982, 0x00F242D8, 0x00A04BEE, 0x000F66EE, 0x005D6FD8,
149  0x00AB7482, 0x00F97DB4, 0x00474336, 0x00154A00, 0x00E3515A, 0x00B1586C, 0x006460D8,
150  0x003669EE, 0x00C072B4, 0x00927B82, 0x002C4500, 0x007E4C36, 0x0088576C, 0x00DA5E5A,
151  0x00D96A82, 0x008B63B4, 0x007D78EE, 0x002F71D8, 0x00914F5A, 0x00C3466C, 0x00355D36,
152  0x00675400, 0x00B26CB4, 0x00E06582, 0x00167ED8, 0x004477EE, 0x00FA496C, 0x00A8405A,
153  0x005E5B00, 0x000C5236, 0x0046FF6C, 0x0014F65A, 0x00E2ED00, 0x00B0E436, 0x000EDAB4,
154  0x005CD382, 0x00AAC8D8, 0x00F8C1EE, 0x002DF95A, 0x007FF06C, 0x0089EB36, 0x00DBE200,
155  0x0065DC82, 0x0037D5B4, 0x00C1CEEE, 0x0093C7D8, 0x0090F300, 0x00C2FA36, 0x0034E16C,
156  0x0066E85A, 0x00D8D6D8, 0x008ADFEE, 0x007CC4B4, 0x002ECD82, 0x00FBF536, 0x00A9FC00,
157  0x005FE75A, 0x000DEE6C, 0x00B3D0EE, 0x00E1D9D8, 0x0017C282, 0x0045CBB4, 0x00EAE6B4,
158  0x00B8EF82, 0x004EF4D8, 0x001CFDEE, 0x00A2C36C, 0x00F0CA5A, 0x0006D100, 0x0054D836,
159  0x0081E082, 0x00D3E9B4, 0x0025F2EE, 0x0077FBD8, 0x00C9C55A, 0x009BCC6C, 0x006DD736,
160  0x003FDE00, 0x003CEAD8, 0x006EE3EE, 0x0098F8B4, 0x00CAF182, 0x0074CF00, 0x0026C636,
161  0x00D0DD6C, 0x0082D45A, 0x0057ECEE, 0x0005E5D8, 0x00F3FE82, 0x00A1F7B4, 0x001FC936,
162  0x004DC000, 0x00BBDB5A, 0x00E9D26C, 0x00E5805A, 0x00B7896C, 0x00419236, 0x00139B00,
163  0x00ADA582, 0x00FFACB4, 0x0009B7EE, 0x005BBED8, 0x008E866C, 0x00DC8F5A, 0x002A9400,
164  0x00789D36, 0x00C6A3B4, 0x0094AA82, 0x0062B1D8, 0x0030B8EE, 0x00338C36, 0x00618500,
165  0x00979E5A, 0x00C5976C, 0x007BA9EE, 0x0029A0D8, 0x00DFBB82, 0x008DB2B4, 0x00588A00,
166  0x000A8336, 0x00FC986C, 0x00AE915A, 0x0010AFD8, 0x0042A6EE, 0x00B4BDB4, 0x00E6B482,
167  0x00499982, 0x001B90B4, 0x00ED8BEE, 0x00BF82D8, 0x0001BC5A, 0x0053B56C, 0x00A5AE36,
168  0x00F7A700, 0x00229FB4, 0x00709682, 0x00868DD8, 0x00D484EE, 0x006ABA6C, 0x0038B35A,
169  0x00CEA800, 0x009CA136, 0x009F95EE, 0x00CD9CD8, 0x003B8782, 0x00698EB4, 0x00D7B036,
170  0x0085B900, 0x0073A25A, 0x0021AB6C, 0x00F493D8, 0x00A69AEE, 0x005081B4, 0x00028882,
171  0x00BCB600, 0x00EEBF36, 0x0018A46C, 0x004AAD5A };
172 
173 inline uint32_t process8(uint32_t crc, uint8_t data)
174  {
175  return (crc >> 8) ^ CRC24_T0[(crc & 0xff) ^ data];
176  }
177 
178 inline uint32_t process32(uint32_t crc, uint32_t word)
179  {
180  crc ^= word;
181  crc = CRC24_T3[(crc >> 0) & 0xff]
182  ^ CRC24_T2[(crc >> 8) & 0xff]
183  ^ CRC24_T1[(crc >> 16) & 0xff]
184  ^ CRC24_T0[(crc >> 24) & 0xff];
185  return crc;
186  }
187 }
188 
189 std::unique_ptr<HashFunction> CRC24::copy_state() const
190  {
191  return std::unique_ptr<HashFunction>(new CRC24(*this));
192  }
193 
194 /*
195 * Update a CRC24 Checksum
196 *
197 * Implementation uses Slicing-by-N algorithm described in
198 * "Novel Table Lookup-Based Algorithms for High-Performance
199 * CRC Generation", by M.Kounavis.
200 *
201 * This algorithm uses 4 precomputed look-up tables. First
202 * table T0 is computed same way as in a method proposed
203 * by D. Sarwate (1988). Then T_1, T2 and T3 are computed
204 * in following way:
205 *
206 * T1[j] = (T0[j] >> 8) ^ T0[ T0[j] & 0xFF ]
207 * T2[j] = (T1[j] >> 8) ^ T0[ T1[j] & 0xFF ]
208 * T3[j] = (T2[j] >> 8) ^ T0[ T2[j] & 0xFF ]
209 *
210 */
211 void CRC24::add_data(const uint8_t input[], size_t length)
212  {
213  uint32_t d[4];
214  uint32_t tmp = m_crc;
215 
216  // Input is word aligned if WA & input == 0
217  static const uint8_t WA = (BOTAN_MP_WORD_BITS/8) - 1;
218 
219  // Ensure input is word aligned before processing in parallel
220  for(;length && (reinterpret_cast<uintptr_t>(input) & WA); length--)
221  tmp = process8(tmp, *input++);
222 
223  while(length >= 16)
224  {
225  load_le(d, input, 4);
226  tmp = process32(tmp, d[0]);
227  tmp = process32(tmp, d[1]);
228  tmp = process32(tmp, d[2]);
229  tmp = process32(tmp, d[3]);
230 
231  input += 16;
232  length -= 16;
233  }
234 
235  while(length--)
236  tmp = process8(tmp, *input++);
237 
238  m_crc = tmp & 0xffffff;
239  }
240 
241 /*
242 * Finalize a CRC24 Checksum
243 */
244 void CRC24::final_result(uint8_t output[])
245  {
246  output[0] = get_byte(3, m_crc);
247  output[1] = get_byte(2, m_crc);
248  output[2] = get_byte(1, m_crc);
249  clear();
250  }
251 
252 }
void clear() override
Definition: crc24.h:27
T load_le(const uint8_t in[], size_t off)
Definition: loadstor.h:121
Definition: alg_id.cpp:13
std::unique_ptr< HashFunction > copy_state() const override
Definition: crc24.cpp:189
uint8_t get_byte(size_t byte_num, T input)
Definition: loadstor.h:39