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Adds support for calculating Cyclic Redundancy Check (CRC) to the Digest module.
- Provides support for the following CRC algorithms:
- {Digest::CRC1 CRC1}
- {Digest::CRC5 CRC5}
- {Digest::CRC8 CRC8}
- {Digest::CRC8_1Wire CRC8 1-Wire}
- {Digest::CRC15 CRC15}
- {Digest::CRC16 CRC16}
- {Digest::CRC16CCITT CRC16 CCITT}
- {Digest::CRC16DNP CRC16 DNP}
- {Digest::CRC16Genibus CRC16 Genibus}
- {Digest::CRC16Kermit CRC16 Kermit}
- {Digest::CRC16Modbus CRC16 Modbus}
- {Digest::CRC16USB CRC16 USB}
- {Digest::CRC16X25 CRC16 X25}
- {Digest::CRC16XModem CRC16 XModem}
- {Digest::CRC16ZModem CRC16 ZModem}
- {Digest::CRC16QT CRC16 QT}
- {Digest::CRC24 CRC24}
- {Digest::CRC32 CRC32}
- {Digest::CRC32BZip2 CRC32 BZip2}
- {Digest::CRC32c CRC32c}
- {Digest::CRC32Jam CRC32 Jam}
- {Digest::CRC32MPEG CRC32 MPEG}
- {Digest::CRC32POSIX CRC32 POSIX}
- {Digest::CRC32XFER CRC32 XFER}
- {Digest::CRC64 CRC64}
- {Digest::CRC64Jones CRC64 Jones}
- {Digest::CRC64XZ CRC64 XZ}
- Pure Ruby implementation.
- Provides CRC Tables for optimized calculations.
- Supports optional C extensions which increases performance by ~40x.
- If the C extensions cannot be compiled for whatever reason, digest-crc will automatically fallback to the pure-Ruby implementation.
gem install digest-crc
Calculate a CRC32:
require 'digest/crc32'
Digest::CRC32.hexdigest('hello')
# => "3610a686"Calculate a CRC32 of a file:
Digest::CRC32.file('README.md')
# => #<Digest::CRC32: 127ad531>Incrementally calculate a CRC32:
crc = Digest::CRC32.new
crc << 'one'
crc << 'two'
crc << 'three'
crc.hexdigest
# => "09e1c092"Directly access the checksum:
crc.checksum
# => 165789842Defining your own CRC class:
require 'digest/crc32'
module Digest
class CRC3000 < CRC32
WIDTH = 4
INIT_CRC = 0xffffffff
XOR_MASK = 0xffffffff
TABLE = [
# ....
].freeze
def update(data)
data.each_byte do |b|
@crc = (((@crc >> 8) & 0x00ffffff) ^ @table[(@crc ^ b) & 0xff])
end
return self
end
end
end$ bundle exec rake clean
$ bundle exec ./benchmarks.rb
Loading Digest::CRC classes ...
Generating 1000 8Kb lengthed strings ...
Benchmarking Digest::CRC classes ...
user system total real
Digest::CRC1#update 0.349756 0.000002 0.349758 ( 0.351427)
Digest::CRC5#update 1.175206 0.000049 1.175255 ( 1.180975)
Digest::CRC8#update 1.023536 0.000015 1.023551 ( 1.029017)
Digest::CRC8_1Wire#update 1.012156 0.000000 1.012156 ( 1.017342)
Digest::CRC15#update 1.187286 0.000005 1.187291 ( 1.193634)
Digest::CRC16#update 0.998527 0.000013 0.998540 ( 1.003940)
Digest::CRC16CCITT#update 1.179864 0.000005 1.179869 ( 1.186134)
Digest::CRC16DNP#update 1.018969 0.000003 1.018972 ( 1.025248)
Digest::CRC16Genibus#update 1.196754 0.000065 1.196819 ( 1.203605)
Digest::CRC16Modbus#update 1.007367 0.000000 1.007367 ( 1.012325)
Digest::CRC16X25#update 1.044127 0.000000 1.044127 ( 1.052010)
Digest::CRC16USB#update 1.012804 0.000000 1.012804 ( 1.018324)
Digest::CRC16X25#update 1.009694 0.000000 1.009694 ( 1.015890)
Digest::CRC16XModem#update 1.210814 0.000000 1.210814 ( 1.217951)
Digest::CRC16ZModem#update 1.175239 0.000000 1.175239 ( 1.181395)
Digest::CRC24#update 1.207431 0.000000 1.207431 ( 1.213373)
Digest::CRC32#update 1.012334 0.000000 1.012334 ( 1.017671)
Digest::CRC32BZip2#update 1.190351 0.000000 1.190351 ( 1.196567)
Digest::CRC32c#update 1.021147 0.000000 1.021147 ( 1.027035)
Digest::CRC32Jam#update 1.002365 0.000000 1.002365 ( 1.007202)
Digest::CRC32MPEG#update 1.161925 0.000000 1.161925 ( 1.168058)
Digest::CRC32POSIX#update 1.191860 0.000967 1.192827 ( 1.198722)
Digest::CRC32XFER#update 1.217692 0.000000 1.217692 ( 1.224075)
Digest::CRC64#update 3.084106 0.000000 3.084106 ( 3.106840)
Digest::CRC64Jones#update 3.016687 0.000000 3.016687 ( 3.038963)
Digest::CRC64XZ#update 3.019690 0.000000 3.019690 ( 3.040971)
$ bundle exec rake build:c_exts
...
$ bundle exec ./benchmarks.rb
Loading Digest::CRC classes ...
Generating 1000 8Kb lengthed strings ...
Benchmarking Digest::CRC classes ...
user system total real
Digest::CRC1#update 0.356025 0.000016 0.356041 ( 0.365345)
Digest::CRC5#update 0.023957 0.000001 0.023958 ( 0.024835)
Digest::CRC8#update 0.021254 0.000007 0.021261 ( 0.024647)
Digest::CRC8_1Wire#update 0.039129 0.000000 0.039129 ( 0.042417)
Digest::CRC15#update 0.030285 0.000000 0.030285 ( 0.030560)
Digest::CRC16#update 0.023003 0.000000 0.023003 ( 0.023267)
Digest::CRC16CCITT#update 0.028207 0.000000 0.028207 ( 0.028467)
Digest::CRC16DNP#update 0.022861 0.000000 0.022861 ( 0.023111)
Digest::CRC16Genibus#update 0.028041 0.000000 0.028041 ( 0.028359)
Digest::CRC16Modbus#update 0.022931 0.000009 0.022940 ( 0.023560)
Digest::CRC16X25#update 0.022808 0.000000 0.022808 ( 0.023054)
Digest::CRC16USB#update 0.022258 0.000882 0.023140 ( 0.023418)
Digest::CRC16X25#update 0.022816 0.000000 0.022816 ( 0.023084)
Digest::CRC16XModem#update 0.027984 0.000000 0.027984 ( 0.028269)
Digest::CRC16ZModem#update 0.027968 0.000000 0.027968 ( 0.028214)
Digest::CRC24#update 0.028426 0.000000 0.028426 ( 0.028687)
Digest::CRC32#update 0.022805 0.000000 0.022805 ( 0.023043)
Digest::CRC32BZip2#update 0.025519 0.000000 0.025519 ( 0.025797)
Digest::CRC32c#update 0.022807 0.000000 0.022807 ( 0.023069)
Digest::CRC32Jam#update 0.023006 0.000000 0.023006 ( 0.023231)
Digest::CRC32MPEG#update 0.025536 0.000000 0.025536 ( 0.025861)
Digest::CRC32POSIX#update 0.025557 0.000000 0.025557 ( 0.025841)
Digest::CRC32XFER#update 0.025310 0.000000 0.025310 ( 0.025599)
Digest::CRC64#update 0.023182 0.000000 0.023182 ( 0.023421)
Digest::CRC64Jones#update 0.022916 0.000000 0.022916 ( 0.023139)
Digest::CRC64XZ#update 0.022879 0.000000 0.022879 ( 0.023131)
$ bundle exec ./benchmarks.rb
Loading Digest::CRC classes ...
Generating 1000 8Kb lengthed strings ...
Benchmarking Digest::CRC classes ...
user system total real
Digest::CRC1#update 1.030000 0.090000 1.120000 ( 0.511189)
Digest::CRC5#update 1.620000 0.060000 1.680000 ( 1.096031)
Digest::CRC8#update 1.560000 0.070000 1.630000 ( 1.083921)
Digest::CRC8_1Wire#update 0.930000 0.040000 0.970000 ( 0.927024)
Digest::CRC15#update 1.590000 0.070000 1.660000 ( 1.132566)
Digest::CRC16#update 1.650000 0.060000 1.710000 ( 1.074508)
Digest::CRC16CCITT#update 1.610000 0.060000 1.670000 ( 1.190860)
Digest::CRC16DNP#update 1.270000 0.010000 1.280000 ( 0.938132)
Digest::CRC16Genibus#update 1.620000 0.030000 1.650000 ( 1.148556)
Digest::CRC16Modbus#update 1.070000 0.020000 1.090000 ( 0.881455)
Digest::CRC16X25#update 1.110000 0.010000 1.120000 ( 0.945366)
Digest::CRC16USB#update 1.140000 0.000000 1.140000 ( 0.984367)
Digest::CRC16X25#update 0.920000 0.010000 0.930000 ( 0.872541)
Digest::CRC16XModem#update 1.530000 0.010000 1.540000 ( 1.092838)
Digest::CRC16ZModem#update 1.720000 0.010000 1.730000 ( 1.164787)
Digest::CRC24#update 1.810000 0.020000 1.830000 ( 1.084953)
Digest::CRC32#update 1.590000 0.010000 1.600000 ( 1.105553)
Digest::CRC32BZip2#update 1.520000 0.010000 1.530000 ( 1.070839)
Digest::CRC32c#update 0.960000 0.010000 0.970000 ( 0.881989)
Digest::CRC32Jam#update 1.030000 0.010000 1.040000 ( 0.907208)
Digest::CRC32MPEG#update 1.420000 0.010000 1.430000 ( 0.994035)
Digest::CRC32POSIX#update 1.530000 0.020000 1.550000 ( 1.106366)
Digest::CRC32XFER#update 1.650000 0.010000 1.660000 ( 1.097647)
Digest::CRC64#update 3.440000 0.030000 3.470000 ( 2.771806)
Digest::CRC64Jones#update 2.630000 0.010000 2.640000 ( 2.628016)
Digest::CRC64XZ#update 3.200000 0.020000 3.220000 ( 2.913442)
Special thanks go out to the pycrc library which is able to generate C source-code for all of the CRC algorithms, including their CRC Tables.
Copyright (c) 2010-2020 Hal Brodigan
See {file:LICENSE.txt} for license information.