1、普通文件（如壓縮文件）的crc32校驗碼計算方法：
生成多項式採用0xEDB88320
This polynomial ( 0xEDB88320L) DOES generate the same CRC values as ZMODEM and PKZIP
local tab = {
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
}
local function xor(a, b)
local calc = 0
for i = 32, 0, -1 do
local val = 2 ^ i
local aa = false
local bb = false
if a == 0 then
calc = calc + b
break
end
if b == 0 then
calc = calc + a
break
end
if a >= val then
aa = true
a = a - val
end
if b >= val then
bb = true
b = b - val
end
if not (aa and bb) and (aa or bb) then
calc = calc + val
end
end
return math.floor(calc)
end
local function lshift(num, left)
local res = num * (2 ^ left)
return res % (2 ^ 32)
end
local function rshift(num, right)
local res = num / (2 ^ right)
return math.floor(res)
end
local CRC32 = {}
function CRC32.hash(str)
local count = string.len(str)
local crc = xor(0,0xFFFFFFFF)
for i=1,count do
local byte = string.byte(str, i)
local a = rshift(crc,8) & 0x00FFFFFF
local b = tab[(xor(crc,byte) & 0xFF)+1]
crc = xor(a , b)
end
crc = xor(crc , 0xFFFFFFFF)
crc = crc | -(crc & lshift(1,31))
crc = crc & 0xFFFFFFFF
return string.format("%x",crc)
end
return CRC322、媒體文件（如mpeg）的crc32校驗碼計算方法：
生成多項式採用0x04c11db7
--Copyright (c) 2007-2008 Neil Richardson ([email protected])
--
--Permission is hereby granted, free of charge, to any person obtaining a copy
--of this software and associated documentation files (the "Software"), to deal
--in the Software without restriction, including without limitation the rights
--to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
--copies of the Software, and to permit persons to whom the Software is
--furnished to do so, subject to the following conditions:
--
--The above copyright notice and this permission notice shall be included in all
--copies or substantial portions of the Software.
--
--THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
--IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
--FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
--AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
--LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
--OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
--IN THE SOFTWARE.
local CRC32_module = {}
local max = 2^32 -1
local CRC32 = {
0,79764919,159529838,222504665,319059676,
398814059,445009330,507990021,638119352,
583659535,797628118,726387553,890018660,
835552979,1015980042,944750013,1276238704,
1221641927,1167319070,1095957929,1595256236,
1540665371,1452775106,1381403509,1780037320,
1859660671,1671105958,1733955601,2031960084,
2111593891,1889500026,1952343757,2552477408,
2632100695,2443283854,2506133561,2334638140,
2414271883,2191915858,2254759653,3190512472,
3135915759,3081330742,3009969537,2905550212,
2850959411,2762807018,2691435357,3560074640,
3505614887,3719321342,3648080713,3342211916,
3287746299,3467911202,3396681109,4063920168,
4143685023,4223187782,4286162673,3779000052,
3858754371,3904687514,3967668269,881225847,
809987520,1023691545,969234094,662832811,
591600412,771767749,717299826,311336399,
374308984,453813921,533576470,25881363,
88864420,134795389,214552010,2023205639,
2086057648,1897238633,1976864222,1804852699,
1867694188,1645340341,1724971778,1587496639,
1516133128,1461550545,1406951526,1302016099,
1230646740,1142491917,1087903418,2896545431,
2825181984,2770861561,2716262478,3215044683,
3143675388,3055782693,3001194130,2326604591,
2389456536,2200899649,2280525302,2578013683,
2640855108,2418763421,2498394922,3769900519,
3832873040,3912640137,3992402750,4088425275,
4151408268,4197601365,4277358050,3334271071,
3263032808,3476998961,3422541446,3585640067,
3514407732,3694837229,3640369242,1762451694,
1842216281,1619975040,1682949687,2047383090,
2127137669,1938468188,2001449195,1325665622,
1271206113,1183200824,1111960463,1543535498,
1489069629,1434599652,1363369299,622672798,
568075817,748617968,677256519,907627842,
853037301,1067152940,995781531,51762726,
131386257,177728840,240578815,269590778,
349224269,429104020,491947555,4046411278,
4126034873,4172115296,4234965207,3794477266,
3874110821,3953728444,4016571915,3609705398,
3555108353,3735388376,3664026991,3290680682,
3236090077,3449943556,3378572211,3174993278,
3120533705,3032266256,2961025959,2923101090,
2868635157,2813903052,2742672763,2604032198,
2683796849,2461293480,2524268063,2284983834,
2364738477,2175806836,2238787779,1569362073,
1498123566,1409854455,1355396672,1317987909,
1246755826,1192025387,1137557660,2072149281,
2135122070,1912620623,1992383480,1753615357,
1816598090,1627664531,1707420964,295390185,
358241886,404320391,483945776,43990325,
106832002,186451547,266083308,932423249,
861060070,1041341759,986742920,613929101,
542559546,756411363,701822548,3316196985,
3244833742,3425377559,3370778784,3601682597,
3530312978,3744426955,3689838204,3819031489,
3881883254,3928223919,4007849240,4037393693,
4100235434,4180117107,4259748804,2310601993,
2373574846,2151335527,2231098320,2596047829,
2659030626,2470359227,2550115596,2947551409,
2876312838,2788305887,2733848168,3165939309,
3094707162,3040238851,2985771188,
}
local function xor(a, b)
local calc = 0
for i = 32, 0, -1 do
local val = 2 ^ i
local aa = false
local bb = false
if a == 0 then
calc = calc + b
break
end
if b == 0 then
calc = calc + a
break
end
if a >= val then
aa = true
a = a - val
end
if b >= val then
bb = true
b = b - val
end
if not (aa and bb) and (aa or bb) then
calc = calc + val
end
end
return calc
end
local function lshift(num, left)
local res = num * (2 ^ left)
return res % (2 ^ 32)
end
local function rshift(num, right)
local res = num / (2 ^ right)
return math.floor(res)
end
function CRC32_module.Hash(str)
local count = string.len(tostring(str))
local crc = max
local i = 1
for i=1,count do
local byte = string.byte(str, i)
crc = xor(lshift(crc, 8), CRC32[xor(rshift(crc, 24), byte) + 1])
end
return crc
end
return CRC32_module
--
-- CRC32.lua
--
-- A pure Lua implementation of a CRC32 hashing algorithm. Slower than using a C implemtation,
-- but useful having no other dependancies.
--
--
-- Synopsis
--
-- require('CRC32')
--
-- crchash = CRC32.Hash('a string')
--
-- Methods:
--
-- hashval = CRC32.Hash(val)
-- Calculates and returns (as an integer) the CRC32 hash of the parameter 'val'.
