# Digest CRC [![CI](https://github.com/postmodern/digest-crc/actions/workflows/ruby.yml/badge.svg)](https://github.com/postmodern/digest-crc/actions/workflows/ruby.yml) * [Source](https://github.com/postmodern/digest-crc) * [Issues](https://github.com/postmodern/digest-crc/issues) * [Documentation](http://rubydoc.info/gems/digest-crc/frames) ## Description Adds support for calculating Cyclic Redundancy Check (CRC) to the Digest module. ## Features * Provides support for the following CRC algorithms: * [CRC1](https://rubydoc.info/gems/digest-crc/Digest/CRC1) * [CRC5](https://rubydoc.info/gems/digest-crc/Digest/CRC5) * [CRC8](https://rubydoc.info/gems/digest-crc/Digest/CRC8) * [CRC8 1-Wire](https://rubydoc.info/gems/digest-crc/Digest/CRC8_1Wire) * [CRC15](https://rubydoc.info/gems/digest-crc/Digest/CRC15) * [CRC16](https://rubydoc.info/gems/digest-crc/Digest/CRC16) * [CRC16 CCITT](https://rubydoc.info/gems/digest-crc/Digest/CRC16CCITT) * [CRC16 DNP](https://rubydoc.info/gems/digest-crc/Digest/CRC16DNP) * [CRC16 Genibus](https://rubydoc.info/gems/digest-crc/Digest/CRC16Genibus) * [CRC16 Kermit](https://rubydoc.info/gems/digest-crc/Digest/CRC16Kermit) * [CRC16 Modbus](https://rubydoc.info/gems/digest-crc/Digest/CRC16Modbus) * [CRC16 USB](https://rubydoc.info/gems/digest-crc/Digest/CRC16USB) * [CRC16 X25](https://rubydoc.info/gems/digest-crc/Digest/CRC16X25) * [CRC16 XModem](https://rubydoc.info/gems/digest-crc/Digest/CRC16XModem) * [CRC16 ZModem](https://rubydoc.info/gems/digest-crc/Digest/CRC16ZModem) * [CRC16 QT](https://rubydoc.info/gems/digest-crc/Digest/CRC16QT) * [CRC24](https://rubydoc.info/gems/digest-crc/Digest/CRC24) * [CRC32](https://rubydoc.info/gems/digest-crc/Digest/CRC32) * [CRC32 BZip2](https://rubydoc.info/gems/digest-crc/Digest/CRC32BZip2) * [CRC32c](https://rubydoc.info/gems/digest-crc/Digest/CRC32c) * [CRC32 Jam](https://rubydoc.info/gems/digest-crc/Digest/CRC32Jam) * [CRC32 MPEG](https://rubydoc.info/gems/digest-crc/Digest/CRC32MPEG) * [CRC32 POSIX](https://rubydoc.info/gems/digest-crc/Digest/CRC32POSIX) * [CRC32 XFER](https://rubydoc.info/gems/digest-crc/Digest/CRC32XFER) * [CRC64](https://rubydoc.info/gems/digest-crc/Digest/CRC64) * [CRC64 Jones](https://rubydoc.info/gems/digest-crc/Digest/CRC64Jones) * [CRC64 XZ](https://rubydoc.info/gems/digest-crc/Digest/CRC64XZ) * 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. ## Install ``` gem install digest-crc ``` **Note:** to enable the C extensions ensure that you are using CRuby and have a C compiler (`gcc` or `clang`) and `make` installed, _before_ installing digest-crc. * Debian / Ubuntu: $ sudo apt install gcc make * RedHat / Fedora: $ sudo dnf install gcc make * Alpine Linux: $ apk add build-base * macOS: install XCode ## Examples Calculate a CRC32: ```ruby require 'digest/crc32' Digest::CRC32.hexdigest('hello') # => "3610a686" ``` Calculate a CRC32 of a file: ```ruby Digest::CRC32.file('README.md') # => # ``` Incrementally calculate a CRC32: ```ruby crc = Digest::CRC32.new crc << 'one' crc << 'two' crc << 'three' crc.hexdigest # => "09e1c092" ``` Directly access the checksum: ```ruby crc.checksum # => 165789842 ``` Defining your own CRC class: ```ruby 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 ``` ## Benchmarks ### Ruby 2.7.4 (pure Ruby) $ 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 0.423741 0.000000 0.423741 ( 0.425887) Digest::CRC5#update 1.486578 0.000011 1.486589 ( 1.493215) Digest::CRC8#update 1.261386 0.000000 1.261386 ( 1.266399) Digest::CRC8_1Wire#update 1.250344 0.000000 1.250344 ( 1.255009) Digest::CRC15#update 1.482515 0.000000 1.482515 ( 1.488131) Digest::CRC16#update 1.216744 0.000811 1.217555 ( 1.222228) Digest::CRC16CCITT#update 1.480490 0.000000 1.480490 ( 1.486745) Digest::CRC16DNP#update 1.200067 0.000000 1.200067 ( 1.204835) Digest::CRC16Genibus#update 1.492910 0.000000 1.492910 ( 1.498923) Digest::CRC16Modbus#update 1.217449 0.000003 1.217452 ( 1.222348) Digest::CRC16QT#update 1.223311 0.000000 1.223311 ( 1.229211) Digest::CRC16USB#update 1.233744 0.000000 1.233744 ( 1.238615) Digest::CRC16X25#update 1.223077 0.000000 1.223077 ( 1.227607) Digest::CRC16XModem#update 1.487674 0.000000 1.487674 ( 1.493316) Digest::CRC16ZModem#update 1.484288 0.000000 1.484288 ( 1.490096) Digest::CRC24#update 1.490272 0.000000 1.490272 ( 1.496027) Digest::CRC32#update 1.225311 0.000000 1.225311 ( 1.230572) Digest::CRC32BZip2#update 1.503096 0.000000 1.503096 ( 1.509202) Digest::CRC32c#update 1.220390 0.000000 1.220390 ( 1.225487) Digest::CRC32Jam#update 1.216066 0.000000 1.216066 ( 1.220591) Digest::CRC32MPEG#update 1.486808 0.000000 1.486808 ( 1.492611) Digest::CRC32POSIX#update 1.494508 0.000957 1.495465 ( 1.503262) Digest::CRC32XFER#update 1.504802 0.005830 1.510632 ( 1.522066) Digest::CRC64#update 3.260784 0.015674 3.276458 ( 3.310506) Digest::CRC64Jones#update 3.195204 0.000000 3.195204 ( 3.213054) Digest::CRC64XZ#update 3.173597 0.000000 3.173597 ( 3.190438) ### Ruby 2.7.4 (C extensions) $ 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 0.443619 0.000007 0.443626 ( 0.446545) Digest::CRC5#update 0.025134 0.000806 0.025940 ( 0.026129) Digest::CRC8#update 0.022564 0.000000 0.022564 ( 0.022775) Digest::CRC8_1Wire#update 0.021427 0.000008 0.021435 ( 0.021551) Digest::CRC15#update 0.030377 0.000833 0.031210 ( 0.031406) Digest::CRC16#update 0.024004 0.000002 0.024006 ( 0.024418) Digest::CRC16CCITT#update 0.026930 0.000001 0.026931 ( 0.027238) Digest::CRC16DNP#update 0.024279 0.000000 0.024279 ( 0.024446) Digest::CRC16Genibus#update 0.026477 0.000004 0.026481 ( 0.026656) Digest::CRC16Modbus#update 0.023568 0.000000 0.023568 ( 0.023704) Digest::CRC16QT#update 0.024161 0.000000 0.024161 ( 0.024316) Digest::CRC16USB#update 0.023891 0.000000 0.023891 ( 0.024038) Digest::CRC16X25#update 0.023849 0.000000 0.023849 ( 0.023991) Digest::CRC16XModem#update 0.026254 0.000000 0.026254 ( 0.026523) Digest::CRC16ZModem#update 0.026391 0.000000 0.026391 ( 0.026529) Digest::CRC24#update 0.028805 0.000854 0.029659 ( 0.029830) Digest::CRC32#update 0.024030 0.000000 0.024030 ( 0.024200) Digest::CRC32BZip2#update 0.026942 0.000000 0.026942 ( 0.027244) Digest::CRC32c#update 0.023989 0.000000 0.023989 ( 0.024159) Digest::CRC32Jam#update 0.023940 0.000000 0.023940 ( 0.024066) Digest::CRC32MPEG#update 0.027063 0.000000 0.027063 ( 0.027213) Digest::CRC32POSIX#update 0.027137 0.000000 0.027137 ( 0.028160) Digest::CRC32XFER#update 0.026956 0.000002 0.026958 ( 0.027103) Digest::CRC64#update 0.024222 0.000005 0.024227 ( 0.024796) Digest::CRC64Jones#update 0.025331 0.000000 0.025331 ( 0.025789) Digest::CRC64XZ#update 0.024131 0.000001 0.024132 ( 0.024348) ### Ruby 3.0.2 (pure Ruby) $ 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 0.331405 0.000002 0.331407 ( 0.333588) Digest::CRC5#update 1.206847 0.000020 1.206867 ( 1.224072) Digest::CRC8#update 1.018571 0.000000 1.018571 ( 1.023002) Digest::CRC8_1Wire#update 1.018802 0.000000 1.018802 ( 1.023292) Digest::CRC15#update 1.207586 0.000000 1.207586 ( 1.212691) Digest::CRC16#update 1.032505 0.000965 1.033470 ( 1.040862) Digest::CRC16CCITT#update 1.198079 0.000000 1.198079 ( 1.203134) Digest::CRC16DNP#update 0.994582 0.000000 0.994582 ( 1.006520) Digest::CRC16Genibus#update 1.190596 0.000000 1.190596 ( 1.196087) Digest::CRC16Modbus#update 1.007826 0.000000 1.007826 ( 1.012934) Digest::CRC16QT#update 0.996298 0.000001 0.996299 ( 1.000255) Digest::CRC16USB#update 0.995806 0.000000 0.995806 ( 0.999822) Digest::CRC16X25#update 1.019589 0.000000 1.019589 ( 1.031010) Digest::CRC16XModem#update 1.146947 0.000000 1.146947 ( 1.150817) Digest::CRC16ZModem#update 1.145145 0.000000 1.145145 ( 1.149483) Digest::CRC24#update 1.149009 0.000000 1.149009 ( 1.152854) Digest::CRC32#update 0.970976 0.000000 0.970976 ( 0.974227) Digest::CRC32BZip2#update 1.148596 0.000000 1.148596 ( 1.152381) Digest::CRC32c#update 0.972566 0.000000 0.972566 ( 0.975790) Digest::CRC32Jam#update 0.975854 0.000000 0.975854 ( 0.979217) Digest::CRC32MPEG#update 1.148578 0.000000 1.148578 ( 1.153088) Digest::CRC32POSIX#update 1.146218 0.000986 1.147204 ( 1.152460) Digest::CRC32XFER#update 1.149823 0.000000 1.149823 ( 1.153692) Digest::CRC64#update 2.869948 0.000016 2.869964 ( 2.884261) Digest::CRC64Jones#update 2.867662 0.000000 2.867662 ( 2.886559) Digest::CRC64XZ#update 2.858847 0.000000 2.858847 ( 2.874058) ### Ruby 3.0.2 (C extensions) $ 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 0.349055 0.000000 0.349055 ( 0.350454) Digest::CRC5#update 0.023144 0.000000 0.023144 ( 0.023248) Digest::CRC8#update 0.021378 0.000000 0.021378 ( 0.021522) Digest::CRC8_1Wire#update 0.021019 0.000000 0.021019 ( 0.021145) Digest::CRC15#update 0.030063 0.000003 0.030066 ( 0.030245) Digest::CRC16#update 0.024395 0.000000 0.024395 ( 0.024572) Digest::CRC16CCITT#update 0.026979 0.000000 0.026979 ( 0.027138) Digest::CRC16DNP#update 0.024665 0.000000 0.024665 ( 0.024844) Digest::CRC16Genibus#update 0.027054 0.000000 0.027054 ( 0.027217) Digest::CRC16Modbus#update 0.023963 0.000000 0.023963 ( 0.024257) Digest::CRC16QT#update 0.024218 0.000000 0.024218 ( 0.024360) Digest::CRC16USB#update 0.024393 0.000000 0.024393 ( 0.024561) Digest::CRC16X25#update 0.025127 0.000000 0.025127 ( 0.025292) Digest::CRC16XModem#update 0.028123 0.000000 0.028123 ( 0.028377) Digest::CRC16ZModem#update 0.028205 0.000000 0.028205 ( 0.028571) Digest::CRC24#update 0.031386 0.000000 0.031386 ( 0.031740) Digest::CRC32#update 0.023832 0.000000 0.023832 ( 0.023948) Digest::CRC32BZip2#update 0.027159 0.000000 0.027159 ( 0.027315) Digest::CRC32c#update 0.024172 0.000000 0.024172 ( 0.024310) Digest::CRC32Jam#update 0.024376 0.000000 0.024376 ( 0.024494) Digest::CRC32MPEG#update 0.026035 0.000784 0.026819 ( 0.026940) Digest::CRC32POSIX#update 0.026784 0.000000 0.026784 ( 0.026907) Digest::CRC32XFER#update 0.026770 0.000000 0.026770 ( 0.026893) Digest::CRC64#update 0.024400 0.000009 0.024409 ( 0.024531) Digest::CRC64Jones#update 0.023477 0.000781 0.024258 ( 0.024390) Digest::CRC64XZ#update 0.024611 0.000000 0.024611 ( 0.024779) ### JRuby 9.2.18.0 (pure Ruby) $ bundle exec ./benchmarks.rb Loading Digest::CRC classes ... Generating 1000 8Kb lengthed strings ... Benchmarking Digest::CRC classes ... user system total real Digest::CRC1#update 1.080000 0.050000 1.130000 ( 0.676022) Digest::CRC5#update 2.030000 0.040000 2.070000 ( 1.089240) Digest::CRC8#update 1.590000 0.000000 1.590000 ( 0.999138) Digest::CRC8_1Wire#update 0.920000 0.010000 0.930000 ( 0.873813) Digest::CRC15#update 1.470000 0.030000 1.500000 ( 1.118886) Digest::CRC16#update 1.780000 0.010000 1.790000 ( 1.067874) Digest::CRC16CCITT#update 1.500000 0.070000 1.570000 ( 1.185564) Digest::CRC16DNP#update 1.250000 0.000000 1.250000 ( 0.972322) Digest::CRC16Genibus#update 1.700000 0.010000 1.710000 ( 1.092047) Digest::CRC16Modbus#update 1.000000 0.010000 1.010000 ( 0.915328) Digest::CRC16QT#update 1.250000 0.000000 1.250000 ( 0.968528) Digest::CRC16USB#update 1.150000 0.010000 1.160000 ( 0.990387) Digest::CRC16X25#update 0.940000 0.000000 0.940000 ( 0.926926) Digest::CRC16XModem#update 1.390000 0.010000 1.400000 ( 1.100584) Digest::CRC16ZModem#update 1.760000 0.020000 1.780000 ( 1.094003) Digest::CRC24#update 1.690000 0.010000 1.700000 ( 1.106875) Digest::CRC32#update 1.410000 0.020000 1.430000 ( 1.082506) Digest::CRC32BZip2#update 1.510000 0.010000 1.520000 ( 1.104225) Digest::CRC32c#update 1.270000 0.010000 1.280000 ( 1.023881) Digest::CRC32Jam#update 1.190000 0.010000 1.200000 ( 0.998146) Digest::CRC32MPEG#update 1.580000 0.010000 1.590000 ( 1.099086) Digest::CRC32POSIX#update 1.550000 0.010000 1.560000 ( 1.142051) Digest::CRC32XFER#update 1.360000 0.000000 1.360000 ( 1.071381) Digest::CRC64#update 3.730000 0.020000 3.750000 ( 2.780390) Digest::CRC64Jones#update 2.710000 0.020000 2.730000 ( 2.608007) Digest::CRC64XZ#update 2.910000 0.020000 2.930000 ( 2.629401) ### TruffleRuby 21.2.0 (pure Ruby) $ 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 0.455340 0.000000 0.455340 ( 0.457710) Digest::CRC5#update 1.406700 0.000000 1.406700 ( 1.412535) Digest::CRC8#update 1.248323 0.000000 1.248323 ( 1.255452) Digest::CRC8_1Wire#update 1.269434 0.000000 1.269434 ( 1.275315) Digest::CRC15#update 1.428752 0.000000 1.428752 ( 1.434836) Digest::CRC16#update 1.220394 0.000967 1.221361 ( 1.229684) Digest::CRC16CCITT#update 1.434932 0.001000 1.435932 ( 1.452391) Digest::CRC16DNP#update 1.191351 0.000000 1.191351 ( 1.202262) Digest::CRC16Genibus#update 1.434067 0.000000 1.434067 ( 1.440300) Digest::CRC16Modbus#update 1.200827 0.000000 1.200827 ( 1.205658) Digest::CRC16QT#update 1.195077 0.000000 1.195077 ( 1.200328) Digest::CRC16USB#update 1.196266 0.000000 1.196266 ( 1.201262) Digest::CRC16X25#update 1.206690 0.000000 1.206690 ( 1.211781) Digest::CRC16XModem#update 1.430468 0.000000 1.430468 ( 1.436801) Digest::CRC16ZModem#update 1.442524 0.000000 1.442524 ( 1.448624) Digest::CRC24#update 1.447611 0.000018 1.447629 ( 1.454534) Digest::CRC32#update 1.214314 0.000000 1.214314 ( 1.219838) Digest::CRC32BZip2#update 1.427408 0.000000 1.427408 ( 1.433626) Digest::CRC32c#update 1.204985 0.000000 1.204985 ( 1.210273) Digest::CRC32Jam#update 1.235039 0.000000 1.235039 ( 1.240686) Digest::CRC32MPEG#update 1.429731 0.000000 1.429731 ( 1.435404) Digest::CRC32POSIX#update 1.458886 0.000000 1.458886 ( 1.465914) Digest::CRC32XFER#update 1.422109 0.000000 1.422109 ( 1.427635) Digest::CRC64#update 3.283506 0.000000 3.283506 ( 3.303129) Digest::CRC64Jones#update 3.297402 0.000000 3.297402 ( 3.317357) Digest::CRC64XZ#update 3.278551 0.001875 3.280426 ( 3.315165) ### TruffleRuby 21.2.0 (C extensions) $ 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 0.480586 0.000014 0.480600 ( 0.482817) Digest::CRC5#update 0.023795 0.000000 0.023795 ( 0.023941) Digest::CRC8#update 0.020619 0.000000 0.020619 ( 0.020747) Digest::CRC8_1Wire#update 0.020571 0.000000 0.020571 ( 0.020700) Digest::CRC15#update 0.031224 0.000000 0.031224 ( 0.031412) Digest::CRC16#update 0.024013 0.000000 0.024013 ( 0.024174) Digest::CRC16CCITT#update 0.026790 0.000000 0.026790 ( 0.027079) Digest::CRC16DNP#update 0.024253 0.000000 0.024253 ( 0.024427) Digest::CRC16Genibus#update 0.027237 0.000000 0.027237 ( 0.027390) Digest::CRC16Modbus#update 0.024376 0.000000 0.024376 ( 0.024548) Digest::CRC16QT#update 0.024361 0.000000 0.024361 ( 0.024518) Digest::CRC16USB#update 0.024142 0.000000 0.024142 ( 0.024311) Digest::CRC16X25#update 0.024098 0.000000 0.024098 ( 0.024222) Digest::CRC16XModem#update 0.026306 0.000000 0.026306 ( 0.026502) Digest::CRC16ZModem#update 0.026536 0.000000 0.026536 ( 0.026688) Digest::CRC24#update 0.029732 0.000000 0.029732 ( 0.029902) Digest::CRC32#update 0.024219 0.000000 0.024219 ( 0.024391) Digest::CRC32BZip2#update 0.026817 0.000000 0.026817 ( 0.027044) Digest::CRC32c#update 0.023681 0.000000 0.023681 ( 0.023798) Digest::CRC32Jam#update 0.024243 0.000000 0.024243 ( 0.024419) Digest::CRC32MPEG#update 0.026865 0.000000 0.026865 ( 0.027020) Digest::CRC32POSIX#update 0.026583 0.000000 0.026583 ( 0.026748) Digest::CRC32XFER#update 0.027423 0.000000 0.027423 ( 0.027615) Digest::CRC64#update 0.024150 0.000000 0.024150 ( 0.024310) Digest::CRC64Jones#update 0.024218 0.000000 0.024218 ( 0.024363) Digest::CRC64XZ#update 0.024124 0.000000 0.024124 ( 0.024255) ## Crystal [crystal-crc] is a [Crystal][crystal-lang] port of this library. [crystal-crc]: https://github.com/postmodern/crystal-crc [crystal-lang]: https://www.crystal-lang.org/ ## Thanks Special thanks go out to the [pycrc](http://www.tty1.net/pycrc/) library which is able to generate C source-code for all of the CRC algorithms, including their CRC Tables. ## License Copyright (c) 2010-2021 Hal Brodigan See {file:LICENSE.txt} for license information.