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CRC-32

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Revision as of 15:53, 1 October 2018 by Hout (talk | contribs) (→Python: added a declarative variant using map, reduce)
Task
CRC-32
You are encouraged to solve this task according to the task description, using any language you may know.


Task

Demonstrate a method of deriving the Cyclic Redundancy Check from within the language.


The result should be in accordance with ISO 3309, ITU-T V.42, Gzip and PNG.

Algorithms are described on Computation of CRC in Wikipedia. This variant of CRC-32 uses LSB-first order, sets the initial CRC to FFFFFFFF16, and complements the final CRC.

For the purpose of this task, generate a CRC-32 checksum for the ASCII encoded string:

The quick brown fox jumps over the lazy dog



Ada

Works with: GNAT

<lang Ada>with Ada.Text_IO; use Ada.Text_IO; with GNAT.CRC32; use GNAT.CRC32; with Interfaces; use Interfaces; procedure TestCRC is 

  package IIO is new Ada.Text_IO.Modular_IO (Unsigned_32);
  crc : CRC32;
  num : Unsigned_32;
  str : String := "The quick brown fox jumps over the lazy dog";

begin 

  Initialize (crc);
  Update (crc, str);
  num := Get_Value (crc);
  IIO.Put (num, Base => 16); New_Line;

end TestCRC;</lang>

Output:
16#414FA339#

ALGOL 68

<lang algol68> [0:255]BITS crc_table; BOOL crc_table_computed := FALSE;

PROC make_crc_table = VOID: 

  BEGIN 
     INT n, k;
     FOR n FROM 0 TO 255 DO 
        BITS c := BIN n;
        FOR k TO 8 DO 
           c := IF 32 ELEM c THEN 
                   16redb88320 XOR (c SHR 1)
                ELSE
                   c SHR 1

FI OD; crc_table[n] := c 

     OD;
     crc_table_computed := TRUE
  END;

PROC update_crc = (BITS crc, STRING buf) BITS: 

  BEGIN 
     BITS c := crc XOR 16rffffffff;
     INT n;

     IF NOT crc_table_computed THEN make_crc_table FI;
     FOR n TO UPB buf DO 
        c := crc_table[ABS ((c XOR BIN ABS buf[n]) AND 16rff)] XOR (c SHR 8)
     OD ;
     c XOR 16rffffffff
  END;

PROC hex = (BITS x) STRING :
  BEGIN
     PROC hexdig = (BITS x) CHAR: REPR (IF ABS x ≤ 9 THEN ABS x + ABS "0"
                                        ELSE ABS x - 10 + ABS "a"

FI); 

     STRING h := "";
     IF x = 16r0 THEN

h := "0" 

     ELSE

BITS n := x; WHILE h := hexdig (n AND 16rf) + h; n ≠ 16r0 DO n := n SHR 4 OD 

     FI;
     h
  END;

PROC crc = (STRING buf) BITS: 

  update_crc(16r0, buf);

STRING s = "The quick brown fox jumps over the lazy dog"; print(("CRC32 OF ", s, " is: ", hex (crc (s)), newline)) </lang>

Output:
CRC32 OF The quick brown fox jumps over the lazy dog is: 0414fa339

AutoHotkey

DllCall / WinAPI

<lang AutoHotkey>CRC32(str, enc = "UTF-8") { 

   l := (enc = "CP1200" || enc = "UTF-16") ? 2 : 1, s := (StrPut(str, enc) - 1) * l
   VarSetCapacity(b, s, 0) && StrPut(str, &b, floor(s / l), enc)
   CRC32 := DllCall("ntdll.dll\RtlComputeCrc32", "UInt", 0, "Ptr", &b, "UInt", s)
   return Format("{:#x}", CRC32)

}

MsgBox % CRC32("The quick brown fox jumps over the lazy dog")</lang>

Output:
0x414fa339

Implementation

<lang AutoHotkey>CRC32(str) { 

   static table := []
   loop 256 {
       crc := A_Index - 1
       loop 8
           crc := (crc & 1) ? (crc >> 1) ^ 0xEDB88320 : (crc >> 1)
       table[A_Index - 1] := crc
   }
   crc := ~0
   loop, parse, str
       crc := table[(crc & 0xFF) ^ Asc(A_LoopField)] ^ (crc >> 8)
   return Format("{:#x}", ~crc)

}

MsgBox % CRC32("The quick brown fox jumps over the lazy dog")</lang>

Output:
0x414fa339

C

Library

Using zlib's crc32: <lang c>#include <stdio.h>

  1. include <string.h>
  2. include <zlib.h>

int main() { const char *s = "The quick brown fox jumps over the lazy dog"; printf("%lX\n", crc32(0, (const void*)s, strlen(s)));

return 0; }</lang>

Implementation

This code is a translation from Ruby, with an adjustment to use 32-bit integers. This code happens to resemble the examples from RFC 1952 section 8 and from PNG annex D, because those examples use an identical table.

<lang c>#include <inttypes.h>

  1. include <stdio.h>
  2. include <string.h>

uint32_t rc_crc32(uint32_t crc, const char *buf, size_t len) { static uint32_t table[256]; static int have_table = 0; uint32_t rem; uint8_t octet; int i, j; const char *p, *q;

/* This check is not thread safe; there is no mutex. */ if (have_table == 0) { /* Calculate CRC table. */ for (i = 0; i < 256; i++) { rem = i; /* remainder from polynomial division */ for (j = 0; j < 8; j++) { if (rem & 1) { rem >>= 1; rem ^= 0xedb88320; } else rem >>= 1; } table[i] = rem; } have_table = 1; }

crc = ~crc; q = buf + len; for (p = buf; p < q; p++) { octet = *p; /* Cast to unsigned octet. */ crc = (crc >> 8) ^ table[(crc & 0xff) ^ octet]; } return ~crc; }

int main() { const char *s = "The quick brown fox jumps over the lazy dog"; printf("%" PRIX32 "\n", rc_crc32(0, s, strlen(s)));

return 0; }</lang>

C++

<lang cpp>#include <algorithm>

  1. include <array>
  2. include <cstdint>
  3. include <numeric>

// These headers are only needed for main(), to demonstrate.

  1. include <iomanip>
  2. include <iostream>
  3. include <string>

// Generates a lookup table for the checksums of all 8-bit values. std::array<std::uint_fast32_t, 256> generate_crc_lookup_table() noexcept { 

 auto const reversed_polynomial = std::uint_fast32_t{0xEDB88320uL};
 
 // This is a function object that calculates the checksum for a value,
 // then increments the value, starting from zero.
 struct byte_checksum
 {
   std::uint_fast32_t operator()() noexcept
   {
     auto checksum = static_cast<std::uint_fast32_t>(n++);
     
     for (auto i = 0; i < 8; ++i)
       checksum = (checksum >> 1) ^ ((checksum & 0x1u) ? reversed_polynomial : 0);
     
     return checksum;
   }
   
   unsigned n = 0;
 };
 
 auto table = std::array<std::uint_fast32_t, 256>{};
 std::generate(table.begin(), table.end(), byte_checksum{});
 
 return table;

}

// Calculates the CRC for any sequence of values. (You could use type traits and a // static assert to ensure the values can be converted to 8 bits.) template <typename InputIterator> std::uint_fast32_t crc(InputIterator first, InputIterator last) { 

 // Generate lookup table only on first use then cache it - this is thread-safe.
 static auto const table = generate_crc_lookup_table();
 
 // Calculate the checksum - make sure to clip to 32 bits, for systems that don't
 // have a true (fast) 32-bit type.
 return std::uint_fast32_t{0xFFFFFFFFuL} &
   ~std::accumulate(first, last,
     ~std::uint_fast32_t{0} & std::uint_fast32_t{0xFFFFFFFFuL},
       [](std::uint_fast32_t checksum, std::uint_fast8_t value) 
         { return table[(checksum ^ value) & 0xFFu] ^ (checksum >> 8); });

}

int main() { 

 auto const s = std::string{"The quick brown fox jumps over the lazy dog"};
 
 std::cout << std::hex << std::setw(8) << std::setfill('0') << crc(s.begin(), s.end()) << '\n';

} </lang>

Output:
414fa339

"The quick brown fox jumps over the lazy dog"
(to hex ...)
54686520717569636B2062726F776E20666F78206A756D7073206F76657220746865206C617A7920646F67 414FA339
[other useful test vectors]
0000000000000000000000000000000000000000000000000000000000000000 190A55AD
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FF6CAB0B
000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F 91267E8A
Library: boost

<lang cpp>#include <boost\crc.hpp>

  1. include <string>
  2. include <iostream>

int main() { 

   std::string str( "The quick brown fox jumps over the lazy dog" );
   boost::crc_32_type  crc;
   crc.process_bytes( str.data(), str.size() );

   std::cout << "Checksum: " << std::hex << crc.checksum() << std::endl;
   return 0;

}</lang>

Output:
Checksum: 414fa339

C#

<lang Csharp> 

   /// <summary>
   /// Performs 32-bit reversed cyclic redundancy checks.
   /// </summary>
   public class Crc32
   {
       #region Constants
       /// <summary>
       /// Generator polynomial (modulo 2) for the reversed CRC32 algorithm. 
       /// </summary>
       private const UInt32 s_generator = 0xEDB88320;
       #endregion

       #region Constructors
       /// <summary>
       /// Creates a new instance of the Crc32 class.
       /// </summary>
       public Crc32()
       {
           // Constructs the checksum lookup table. Used to optimize the checksum.
           m_checksumTable = Enumerable.Range(0, 256).Select(i =>
           {
               var tableEntry = (uint)i;
               for (var j = 0; j < 8; ++j)
               {
                   tableEntry = ((tableEntry & 1) != 0)
                       ? (s_generator ^ (tableEntry >> 1)) 
                       : (tableEntry >> 1);
               }
               return tableEntry;
           }).ToArray();
       }
       #endregion

       #region Methods
       /// <summary>
       /// Calculates the checksum of the byte stream.
       /// </summary>
       /// <param name="byteStream">The byte stream to calculate the checksum for.</param>
       /// <returns>A 32-bit reversed checksum.</returns>
       public UInt32 Get<T>(IEnumerable<T> byteStream)
       {
           try
           {
               // Initialize checksumRegister to 0xFFFFFFFF and calculate the checksum.
               return ~byteStream.Aggregate(0xFFFFFFFF, (checksumRegister, currentByte) => 
                         (m_checksumTable[(checksumRegister & 0xFF) ^ Convert.ToByte(currentByte)] ^ (checksumRegister >> 8)));
           }
           catch (FormatException e)
           {
               throw new CrcException("Could not read the stream out as bytes.", e);
           }
           catch (InvalidCastException e)
           {
               throw new CrcException("Could not read the stream out as bytes.", e);
           }
           catch (OverflowException e)
           {
               throw new CrcException("Could not read the stream out as bytes.", e);
           }
       }
       #endregion

       #region Fields
       /// <summary>
       /// Contains a cache of calculated checksum chunks.
       /// </summary>
       private readonly UInt32[] m_checksumTable;

       #endregion
   }

</lang>

Test: <lang Csharp> var arrayOfBytes = Encoding.ASCII.GetBytes("The quick brown fox jumps over the lazy dog");

var crc32 = new Crc32(); Console.WriteLine(crc32.Get(arrayOfBytes).ToString("X")); </lang>

Output:

414fa339

Clojure

Translation of: Java

<lang clojure>(let [crc (new java.util.zip.CRC32) 

     str "The quick brown fox jumps over the lazy dog"]
 (. crc update (. str getBytes))
 (printf "CRC-32('%s') = %s\n" str (Long/toHexString (. crc getValue))))</lang>
Output:
CRC-32('The quick brown fox jumps over the lazy dog') = 414fa339

COBOL

Works with: GnuCOBOL
Library: zlib

<lang COBOL> *> tectonics: cobc -xj crc32-zlib.cob -lz 

      identification division.
      program-id. rosetta-crc32.

      environment division.
      configuration section.
      repository.
          function all intrinsic.

      data division.
      working-storage section.
      01 crc32-initial        usage binary-c-long.
      01 crc32-result         usage binary-c-long unsigned.
      01 crc32-input.
         05 value "The quick brown fox jumps over the lazy dog".
      01 crc32-hex            usage pointer.

      procedure division.
      crc32-main.

     *> libz crc32
      call "crc32" using
          by value crc32-initial
          by reference crc32-input
          by value length(crc32-input)
          returning crc32-result
          on exception
              display "error: no crc32 zlib linkage" upon syserr
      end-call
      call "printf" using "checksum: %lx" & x"0a" by value crc32-result

     *> GnuCOBOL pointers are displayed in hex by default
      set crc32-hex up by crc32-result
      display 'crc32 of "' crc32-input '" is ' crc32-hex

      goback.
      end program rosetta-crc32.</lang>
Output:
prompt$ cobc -xj crc32-zlib.cob -lz
checksum: 414fa339
crc32 of "The quick brown fox jumps over the lazy dog" is 0x00000000414fa339

CoffeeScript

Allows the specification of the initial CRC value, which defaults to 0xFFFFFFFF. Optimized for speed and terseness (then readability/indentation). <lang coffeescript> crc32 = do -> 

 table =
   for n in [0..255]
     for [0..7]
       if n & 1
         n = 0xEDB88320 ^ n >>> 1
       else
         n >>>= 1
     n
 (str, crc = -1) ->
   for c in str
     crc = crc >>> 8 ^ table[(crc ^ c.charCodeAt 0) & 255]
   (crc ^ -1) >>> 0

</lang> Test: <lang coffeescript>console.log (crc32 'The quick brown fox jumps over the lazy dog').toString 16</lang> Output: <lang>414fa339</lang>

Common Lisp

Library: Ironclad

<lang lisp>(ql:quickload :ironclad) (defun string-to-digest (str digest) 

 "Return the specified digest for the ASCII string as a hex string."
 (ironclad:byte-array-to-hex-string 
   (ironclad:digest-sequence digest 
                             (ironclad:ascii-string-to-byte-array str))))

(string-to-digest "The quick brown fox jumps over the lazy dog" :crc32) </lang>

Output:
"414fa339"

Component Pascal

BlackBox Component Builder
Require ZLib Subsystem <lang oberon2> MODULE BbtComputeCRC32; IMPORT ZlibCrc32,StdLog;

PROCEDURE Do*; VAR s: ARRAY 128 OF SHORTCHAR; BEGIN s := "The quick brown fox jumps over the lazy dog"; StdLog.IntForm(ZlibCrc32.CRC32(0,s,0,LEN(s$)),16,12,'0',TRUE); StdLog.Ln; END Do; END BbtComputeCRC32. </lang> Execute: ^Q BbtComputeCRC32.Do

Output:
0414FA339%16

D

<lang d>void main() { 

   import std.stdio, std.digest.crc;

   "The quick brown fox jumps over the lazy dog"
   .crc32Of.crcHexString.writeln;

}</lang>

Output:
414FA339

Elixir

<lang elixir>defmodule Test do 

 def crc32(str) do
   IO.puts :erlang.crc32(str) |> Integer.to_string(16)
 end

end

Test.crc32("The quick brown fox jumps over the lazy dog")</lang>

Output:
414FA339

Erlang

Using the built-in crc32 implementation.

<lang erlang> -module(crc32). -export([test/0]). test() -> 

 io:fwrite("~.16#~n",[erlang:crc32(<<"The quick brown fox jumps over the lazy dog">>)]).

</lang>

Output:

<lang erlang> 16#414FA339 </lang>

Factor

Like SHA-1#Factor, but with crc32. 

IN: scratchpad USING: checksums checksums.crc32 ;
IN: scratchpad "The quick brown fox jumps over the lazy dog" crc32
               checksum-bytes hex-string .
"414fa339"

The implementation is at core/checksums/crc32/crc32.factor.

FBSL

<lang qbasic>#APPTYPE CONSOLE

PRINT HEX(CHECKSUM("The quick brown fox jumps over the lazy dog"))

PAUSE</lang>

Output:
414FA339

Press any key to continue...

Forth

This code can implement other types of CRC by using other polynomial constants: use $8408 for CCITT CRC-16, or $a001 for IBM CRC-16.

<lang forth>

crc/ ( n -- n ) 8 0 do dup 1 rshift swap 1 and if $edb88320 xor then loop ;
crcfill 256 0 do i crc/ , loop ;

create crctbl crcfill

crc+ ( crc n -- crc' ) over xor $ff and cells crctbl + @ swap 8 rshift xor ;
crcbuf ( crc str len -- crc ) bounds ?do i c@ crc+ loop ;

$ffffffff s" The quick brown fox jumps over the lazy dog" crcbuf $ffffffff xor hex. bye \ $414FA339 </lang>

Fortran

<lang fortran>module crc32_m 

   use iso_fortran_env
   implicit none
   integer(int32) :: crc_table(0:255)

contains 

   subroutine update_crc(a, crc)
       integer :: n, i
       character(*) :: a
       integer(int32) :: crc
       
       crc = not(crc)
       n = len(a)
       do i = 1, n
           crc = ieor(shiftr(crc, 8), crc_table(iand(ieor(crc, iachar(a(i:i))), 255)))
       end do
       crc = not(crc)
   end subroutine
   
   subroutine init_table
       integer :: i, j
       integer(int32) :: k
       
       do i = 0, 255
           k = i
           do j = 1, 8
               if (btest(k, 0)) then
                   k = ieor(shiftr(k, 1), -306674912)
               else
                   k = shiftr(k, 1)
               end if
           end do
           crc_table(i) = k
       end do
   end subroutine

end module

program crc32 

   use crc32_m
   implicit none
   integer(int32) :: crc = 0
   character(*), parameter :: s = "The quick brown fox jumps over the lazy dog"
   call init_table
   call update_crc(s, crc)
   print "(Z8)", crc

end program</lang>

FreeBASIC

Translation of: C

<lang freebasic>' version 18-03-2017 ' compile with: fbc -s console

Function crc32(buf As String) As UInteger<32> 

   Static As UInteger<32> table(256)
   Static As UInteger<32> have_table
   Dim As UInteger<32> crc, k
   Dim As ULong i, j

   If have_table = 0 Then
       For i = 0 To 255
           k = i
           For j = 0 To 7
               If (k And 1) Then
                   k Shr= 1
                   k Xor= &Hedb88320
               Else
                   k Shr= 1
               End If
               table(i) = k
           Next
       Next
       have_table = 1
   End If

   crc = Not crc ' crc = &Hffffffff
   
   For i = 0 To Len(buf) -1
       crc = (crc Shr 8) Xor table((crc And &hff) Xor buf[i])
   Next

   Return Not crc

End Function

' ------=< MAIN >=------

Dim As String l = "The quick brown fox jumps over the lazy dog" Dim As UInteger<32> crc

Print "input = "; l print Print "The CRC-32 checksum = "; Hex(crc32(l), 8)

' empty keyboard buffer While Inkey <> "" : Wend Print : Print "hit any key to end program" Sleep End</lang>

Output:
input = The quick brown fox jumps over the lazy dog

The CRC-32 checksum = 414FA339

Go

Library

<lang go>package main

import ( 

   "fmt"
   "hash/crc32"

)

func main() { 

   s := []byte("The quick brown fox jumps over the lazy dog")
   result := crc32.ChecksumIEEE(s)
   fmt.Printf("%X\n", result)

}</lang>

Output:
414FA339

Implementation

<lang go>package main

import "fmt"

var table [256]uint32

func init() { 

   for i := range table {
       word := uint32(i)
       for j := 0; j < 8; j++ {
           if word&1 == 1 {
               word = (word >> 1) ^ 0xedb88320
           } else {
               word >>= 1
           }
       }
       table[i] = word
   }

}

func crc32(s string) uint32 { 

   crc := ^uint32(0)
   for i := 0; i < len(s); i++ {
       crc = table[byte(crc)^s[i]] ^ (crc >> 8)
   }
   return ^crc

}

func main() { 

   fmt.Printf("%0x\n", crc32("The quick brown fox jumps over the lazy dog"))

}</lang>

Output:
414fa339

Groovy

<lang Groovy>def crc32(byte[] bytes) { 

   new java.util.zip.CRC32().with { update bytes; value }

}</lang> Testing: <lang Groovy>assert '414FA339' == sprintf('%04X', crc32('The quick brown fox jumps over the lazy dog'.bytes))</lang>


Haskell

Pure Haskell:

<lang haskell>import Data.Bits ((.&.), complement, shiftR, xor) import Data.Word (Word32) import Numeric (showHex)

crcTable :: Word32 -> Word32 crcTable = (table !!) . fromIntegral 

 where
   table = ((!! 8) . iterate xf) <$> [0 .. 255]
   shifted x = shiftR x 1
   xf r
     | r .&. 1 == 1 = xor (shifted r) 0xedb88320
     | otherwise = shifted r

charToWord :: Char -> Word32 charToWord = fromIntegral . fromEnum

calcCrc :: String -> Word32 calcCrc = complement . foldl cf (complement 0) 

 where
   cf crc x = xor (shiftR crc 8) (crcTable $ xor (crc .&. 0xff) (charToWord x))

crc32 :: String -> String crc32 = flip showHex [] . calcCrc

main :: IO () main = putStrLn $ crc32 "The quick brown fox jumps over the lazy dog"</lang>

Output:
414fa339


Using the zlib C library ( compile with "ghc -lz file.hs"):

<lang haskell>import Data.List (genericLength) import Numeric (showHex) import Foreign.C

foreign import ccall "zlib.h crc32" zlib_crc32 :: 

              CULong -> CString -> CUInt -> CULong

main :: IO () main = do 

 let s = "The quick brown fox jumps over the lazy dog"
 ptr <- newCString s
 let r = zlib_crc32 0 ptr (genericLength s)
 putStrLn $ showHex r ""</lang>
Output:
414fa339

Icon and Unicon

There is no library function for this so we implement one. Icon/Unicon binary operations apply to large integers so we need to mask to the desired unsigned word size. This also only applies to full bytes. <lang Icon>link hexcvt,printf

procedure main() 

  s := "The quick brown fox jumps over the lazy dog"
  a := "414FA339"
  printf("crc(%i)=%s - implementation is %s\n",
         s,r := crc32(s),if r == a then "correct" else "in error")

end

procedure crc32(s) #: return crc-32 (ISO 3309, ITU-T V.42, Gzip, PNG) of s static crcL,mask initial { 

  crcL := list(256)                            # crc table
  p := [0,1,2,4,5,7,8,10,11,12,16,22,23,26]    # polynomial terms 
  mask := 2^32-1                               # word size mask   
  every (poly := 0) := ior(poly,ishift(1,31-p[1 to *p]))
  every c := n := 0 to *crcL-1 do {            # table 
     every 1 to 8 do 
        c := iand(mask, 
                  if iand(c,1) = 1 then
                     ixor(poly,ishift(c,-1)) 
                  else 
                     ishift(c,-1)
                 )
     crcL[n+1] := c
     }
  }
  
  crc := ixor(0,mask)                          # invert bits
  every crc := iand(mask,
                    ixor(crcL[iand(255,ixor(crc,ord(!s)))+1],ishift(crc,-8)))               
  return hexstring(ixor(crc,mask))             # return hexstring

end</lang>

Library: Icon Programming Library

hexcvt.icn (provides hex and hexstring) printf.icn (provides formatting)

Output:
crc("The quick brown fox jumps over the lazy dog")=414FA339 - implementation is correct

J

<lang j> ((i.32) e. 32 26 23 22 16 12 11 10 8 7 5 4 2 1 0) 128!:3 'The quick brown fox jumps over the lazy dog' _3199229127</lang>

Other possible representations of this result:

<lang j> (2^32x)|((i.32) e. 32 26 23 22 16 12 11 10 8 7 5 4 2 1 0) 128!:3 'The quick brown fox jumps over the lazy dog' 1095738169 

  require'convert'
  hfd (2^32x)|((i.32) e. 32 26 23 22 16 12 11 10 8 7 5 4 2 1 0) 128!:3 'The quick brown fox jumps over the lazy dog'

414FA339</lang>

Java

<lang Java>import java.util.zip.* ;

public class CRCMaker { 

  public static void main( String[ ] args ) {
     String toBeEncoded = new String( "The quick brown fox jumps over the lazy dog" ) ;
     CRC32 myCRC = new CRC32( ) ;
     myCRC.update( toBeEncoded.getBytes( ) ) ;
     System.out.println( "The CRC-32 value is : " + Long.toHexString( myCRC.getValue( ) ) + " !" ) ;
  }

}</lang>

Output:
The CRC-32 value is : 414fa339 !

JavaScript

<lang JavaScript>(() => { 

   'use strict';

   const main = () =>
       showHex(
           crc32('The quick brown fox jumps over the lazy dog')
       );

   // crc32 :: String -> Int
   const crc32 = str => {

       // table :: [Int]
       const table = map(
           n => take(9,
               iterate(
                   x => (
                       x & 1 ? z => 0xEDB88320 ^ z : id
                   )(x >>> 1),
                   n
               )
           )[8],
           enumFromTo(0, 255)
       );
       return (
           foldl(
               (a, c) => (a >>> 8) ^ table[
                   (a ^ c.charCodeAt(0)) & 255
               ],
               -1,
               chars(str)
           ) ^ -1
       );
   };

   // GENERIC ABSTRACTIONS -------------------------------

   // chars :: String -> [Char]
   const chars = s => s.split();

   // enumFromTo :: Int -> Int -> [Int]
   const enumFromTo = (m, n) =>
       Array.from({
           length: 1 + n - m
       }, (_, i) => m + i);

   // foldl :: (a -> b -> a) -> a -> [b] -> a
   const foldl = (f, a, xs) => xs.reduce(f, a);

   // id :: a -> a
   const id = x => x;

   // iterate :: (a -> a) -> a -> Gen [a]
   function* iterate(f, x) {
       let v = x;
       while (true) {
           yield(v);
           v = f(v);
       }
   }

   // map :: (a -> b) -> [a] -> [b]
   const map = (f, xs) => xs.map(f);

   // showHex :: Int -> String
   const showHex = n =>
       n.toString(16);

   // take :: Int -> [a] -> [a]
   // take :: Int -> String -> String
   const take = (n, xs) =>
       xs.constructor.constructor.name !== 'GeneratorFunction' ? (
           xs.slice(0, n)
       ) : [].concat.apply([], Array.from({
           length: n
       }, () => {
           const x = xs.next();
           return x.done ? [] : [x.value];
       }));



   // MAIN -------------
   const result = main();
   return (
       console.log(result),
       result
   );

})();</lang>

Output:
414fa339

Kotlin

<lang scala>// version 1.0.6

import java.util.zip.CRC32

fun main(args: Array<String>) { 

   val text = "The quick brown fox jumps over the lazy dog"
   val crc = CRC32()
   with (crc) {
       update(text.toByteArray())
       println("The CRC-32 checksum of '$text' = ${"%x".format(value)}")
   }

}</lang>

Output:
The CRC-32 checksum of 'The quick brown fox jumps over the lazy dog' = 414fa339

Lingo

Pure Lingo

<lang lingo>crcObj = script("CRC").new()

crc32 = crcObj.crc32("The quick brown fox jumps over the lazy dog")

put crc32 -- <ByteArrayObject length = 4 ByteArray = 0x41, 0x4f, 0xa3, 0x39 >

put crc32.toHexString(1, crc32.length) -- "41 4f a3 39"</lang>

Implementation:

<lang lingo>--**************************************************************************** -- @desc CRC-32 Class -- @file parent script "CRC" -- @version 0.1 --****************************************************************************

property _CRC32Table

-- @constructor

on new me 

 -- used for fast CRC32 calculation
 me._CRC32Table = [\
 0, 1996959894, -301047508, -1727442502, 124634137, 1886057615, -379345611, -1637575261, 249268274, 2044508324,\
 -522852066, -1747789432, 162941995, 2125561021, -407360249, -1866523247, 498536548, 1789927666, -205950648,\
 -2067906082, 450548861, 1843258603, -187386543, -2083289657, 325883990, 1684777152, -43845254, -1973040660,\
 335633487, 1661365465, -99664541, -1928851979, 997073096, 1281953886, -715111964, -1570279054, 1006888145,\
 1258607687, -770865667, -1526024853, 901097722, 1119000684, -608450090, -1396901568, 853044451, 1172266101,\
 -589951537, -1412350631, 651767980, 1373503546, -925412992, -1076862698, 565507253, 1454621731, -809855591,\
 -1195530993, 671266974, 1594198024, -972236366, -1324619484, 795835527, 1483230225, -1050600021, -1234817731,\
 1994146192, 31158534, -1731059524, -271249366, 1907459465, 112637215, -1614814043, -390540237, 2013776290,\
 251722036, -1777751922, -519137256, 2137656763, 141376813, -1855689577, -429695999, 1802195444, 476864866,\
 -2056965928, -228458418, 1812370925, 453092731, -2113342271, -183516073, 1706088902, 314042704, -1950435094,\
 -54949764, 1658658271, 366619977, -1932296973, -69972891, 1303535960, 984961486, -1547960204, -725929758,\
 1256170817, 1037604311, -1529756563, -740887301, 1131014506, 879679996, -1385723834, -631195440, 1141124467,\
 855842277, -1442165665, -586318647, 1342533948, 654459306, -1106571248, -921952122, 1466479909, 544179635,\
 -1184443383, -832445281, 1591671054, 702138776, -1328506846, -942167884, 1504918807, 783551873, -1212326853,\
 -1061524307, -306674912, -1698712650, 62317068, 1957810842, -355121351, -1647151185, 81470997, 1943803523,\
 -480048366, -1805370492, 225274430, 2053790376, -468791541, -1828061283, 167816743, 2097651377, -267414716,\
 -2029476910, 503444072, 1762050814, -144550051, -2140837941, 426522225, 1852507879, -19653770, -1982649376,\
 282753626, 1742555852, -105259153, -1900089351, 397917763, 1622183637, -690576408, -1580100738, 953729732,\
 1340076626, -776247311, -1497606297, 1068828381, 1219638859, -670225446, -1358292148, 906185462, 1090812512,\
 -547295293, -1469587627, 829329135, 1181335161, -882789492, -1134132454, 628085408, 1382605366, -871598187,\
 -1156888829, 570562233, 1426400815, -977650754, -1296233688, 733239954, 1555261956, -1026031705, -1244606671,\
 752459403, 1541320221, -1687895376, -328994266, 1969922972, 40735498, -1677130071, -351390145, 1913087877,\
 83908371, -1782625662, -491226604, 2075208622, 213261112, -1831694693, -438977011, 2094854071, 198958881,\
 -2032938284, -237706686, 1759359992, 534414190, -2118248755, -155638181, 1873836001, 414664567, -2012718362,\
 -15766928, 1711684554, 285281116, -1889165569, -127750551, 1634467795, 376229701, -1609899400, -686959890,\
 1308918612, 956543938, -1486412191, -799009033, 1231636301, 1047427035, -1362007478, -640263460, 1088359270,\
 936918000, -1447252397, -558129467, 1202900863, 817233897, -1111625188, -893730166, 1404277552, 615818150,\
 -1160759803, -841546093, 1423857449, 601450431, -1285129682, -1000256840, 1567103746, 711928724, -1274298825,\
 -1022587231, 1510334235, 755167117]
 return me

end

-- Calculates CRC-32 checksum of string or bytearray -- @param {bytearray|string} input -- @return {bytearray} (4 bytes)

on crc32 (me, input) 

 if stringP(input) then input = bytearray(input)
 crc = -1
 len = input.length
 repeat with i = 1 to len
   if (crc>0) then bitShift8 = crc/256
   else bitShift8 = bitAnd(crc,2147483647)/256+8388608
   crc = bitXor(bitShift8,me._CRC32Table[bitAnd(bitXor(crc,input[i]),255)+1])
 end repeat
 ba = bytearray()
 ba.endian = #bigEndian
 ba.writeInt32(bitXOr(crc,-1))
 ba.position = 1
 return ba

end</lang>

Using an "Xtra" (=binary plugin)

<lang lingo>cx = Xtra("Crypto").new() put cx.cx_crc32_string("The quick brown fox jumps over the lazy dog") -- "414fa339"</lang>

Julia

Works with: Julia version 0.6

<lang Julia>function crc32(crc::Int, str::String) 

   table = zeros(UInt32, 256)

   for i in 0:255
       tmp = i
       for j in 0:7
           if tmp & 1 == 1
               tmp >>= 1
               tmp ⊻= 0xedb88320
           else
               tmp >>= 1
           end
       end

       table[i + 1] = tmp
   end

   crc ⊻= 0xffffffff

   for i in UInt32.(collect(str))
       crc = (crc >> 8) ⊻ table[(crc & 0xff) ⊻ i + 1]
   end

   crc ⊻ 0xffffffff

end

str = "The quick brown fox jumps over the lazy dog" crc = crc32(0, str) assert(crc == 0x414fa339) println("Message: ", str) println("Checksum: ", hex(crc))</lang>

Output:
Message: The quick brown fox jumps over the lazy dog
Checksum: 414fa339


M2000 Interpreter

Using Code

<lang M2000 Interpreter> Module CheckIt { 

     Function PrepareTable {
           Dim Base 0, table(256)
           For i = 0 To 255 {
                   k = i
                   For j = 0 To 7 {
                             If binary.and(k,1)=1 Then {
                                 k =binary.Xor(binary.shift(k, -1) ,  0xEDB88320)
                             }  Else k=binary.shift(k, -1)
                   }
                   table(i) = k
            }
            =table()      
     }       
     crctable=PrepareTable()
     crc32= lambda crctable (buf$) -> {
               crc =0xFFFFFFFF
               For i = 0 To Len(buf$) -1
                    crc = binary.xor(binary.shift(crc, -8), array(crctable, binary.xor(binary.and(crc, 0xff), asc(mid$(buf$, i+1, 1)))))
               Next i
               =0xFFFFFFFF-crc       
     }
     Print crc32("The quick brown fox jumps over the lazy dog")=0x414fa339

} CheckIt </lang>

Using Api

<lang M2000 Interpreter> Module CheckApi { 

     Declare CRC32 LIB "ntdll.RtlComputeCrc32" {Long Zero, a$, long s}
     a$=Str$("The quick brown fox jumps over the lazy dog")
     l=len(a$)*2
     Hex Uint(CRC32(0,a$,l))

} CheckApi </lang>

Mathematica / Wolfram Language

<lang Mathematica>type="CRC32"; (*pick one out of 13 predefined hash types*) StringForm[ "The "<>type<>" hash code of \"``\" is ``.", s="The quick brown fox jumps over the lazy dog", Hash[s,type,"HexString"] ] </lang>

Output:
The CRC32 hash code of "The quick brown fox jumps over the lazy dog" is 414fa339.

NetRexx

Translation of: Java

<lang NetRexx>/* NetRexx */ options replace format comments java crossref symbols binary

import java.util.zip.CRC32

toBeEncoded = String("The quick brown fox jumps over the lazy dog") myCRC = CRC32() myCRC.update(toBeEncoded.getBytes()) say "The CRC-32 value is :" Long.toHexString(myCRC.getValue()) "!"

return </lang>

Output:
The CRC-32 value is : 414fa339 !

Nim

<lang nim>import unsigned, strutils

type TCrc32* = uint32 const InitCrc32* = TCrc32(-1)

proc createCrcTable(): array[0..255, TCrc32] = 

 for i in 0..255:
   var rem = TCrc32(i)
   for j in 0..7:
     if (rem and 1) > 0: rem = (rem shr 1) xor TCrc32(0xedb88320)
     else: rem = rem shr 1
   result[i] = rem
  1. Table created at compile time

const crc32table = createCrcTable()

proc crc32(s: string): TCrc32 = 

 result = InitCrc32
 for c in s:
   result = (result shr 8) xor crc32table[(result and 0xff) xor ord(c)]
 result = not result

echo crc32("The quick brown fox jumps over the lazy dog").int64.toHex(8)</lang>

Output:
414FA339

Oberon-2

Works with: oo2c Version 2

<lang oberon2> MODULE CRC32; IMPORT 

 NPCT:Zlib,
 Strings,
 Out;

VAR 

 s: ARRAY 128 OF CHAR;

BEGIN 

 COPY("The quick brown fox jumps over the lazy dog",s);
 Out.Hex(Zlib.CRC32(0,s,0,Strings.Length(s)),0);Out.Ln

END CRC32. </lang>

Output:
414FA339

OCaml

Library: camlzip

<lang ocaml>let () = 

 let s = "The quick brown fox jumps over the lazy dog" in
 let crc = Zlib.update_crc 0l s 0 (String.length s) in
 Printf.printf "crc: %lX\n" crc</lang>

Running this code in interpreted mode:[[Media:Insert non-formatted text here]][[File:[Example.jpg][http://www.example.com link title]]] 

$ ocaml unix.cma -I +zip zip.cma crc.ml
crc: 414FA339

ooRexx

This Program shows how easy it is to use JAVA functionality from ooRexx. bsf4oorexx from Sourceforge https://sourceforge.net/projects/bsf4oorexx/ makes that possible. <lang oorexx>/* ooRexx */ clzCRC32=bsf.importClass("java.util.zip.CRC32") myCRC32 =clzCRC32~new toBeEncoded="The quick brown fox jumps over the lazy dog" myCRC32~update(BsfRawBytes(toBeEncoded)) numeric digits 20 say 'The CRC-32 value of "'toBeEncoded'" is:' myCRC32~getValue~d2x

requires "BSF.CLS" -- get Java bridge </lang>
Output:
The CRC-32 value of "The quick brown fox jumps over the lazy dog" is: 414FA339

PARI/GP

Using Linux system library (Linux only solution)

Library: libz.so

<lang parigp> install("crc32", "lLsL", "crc32", "libz.so"); s = "The quick brown fox jumps over the lazy dog"; printf("%0x\n", crc32(0, s, #s)) </lang>

Output: 

414fa339

Perl

<lang Perl>#!/usr/bin/perl use 5.010 ; use strict ; use warnings ; use Digest::CRC qw( crc32 ) ;

my $crc = Digest::CRC->new( type => "crc32" ) ; $crc->add ( "The quick brown fox jumps over the lazy dog" )  ; say "The checksum is " . $crc->hexdigest( ) ; </lang>

Output:
The checksum is 414fa339

Perl 6

Call to native function crc32 in zlib

<lang perl6>use NativeCall;

sub crc32(int32 $crc, Buf $buf, int32 $len --> int32) is native('z') { * }

my $buf = 'The quick brown fox jumps over the lazy dog'.encode; say crc32(0, $buf, $buf.bytes).fmt('%08x');</lang>

The libary name "z" resolves to /usr/lib/libz.so on a typical Linux system and /usr/lib/libz.dylib on Mac OS X, but may need to be changed for other platforms. Types may be platform-dependent as well. As written, the solution has been tested on Mac OS X 10.5.8 and Arch Linux 2016.08.01 x86_64.

Output:
414fa339

Pure Perl 6

A fairly generic implementation with no regard to execution speed:

<lang perl6>sub crc( 

   Blob $buf,
            # polynomial including leading term, default: ISO 3309/PNG/gzip
   :@poly = (1,0,0,0,0,0,1,0,0,1,1,0,0,0,0,0,1,0,0,0,1,1,1,0,1,1,0,1,1,0,1,1,1),
   :$n = @poly.end,      # degree of polynomial
   :@init = 1 xx $n,     # initial XOR bits
   :@fini = 1 xx $n,     # final XOR bits
   :@bitorder = 0..7,    # default: eat bytes LSB-first
   :@crcorder = 0..$n-1, # default: MSB of checksum is coefficient of x⁰

) { 

   my @bit = flat ($buf.list X+& (1 X+< @bitorder))».so».Int, 0 xx $n;

   @bit[0   .. $n-1] «+^=» @init;
   @bit[$_  ..$_+$n] «+^=» @poly if @bit[$_] for 0..@bit.end-$n;
   @bit[*-$n..  *-1] «+^=» @fini;

   :2[@bit[@bit.end X- @crcorder]];

}

say crc('The quick brown fox jumps over the lazy dog'.encode('ascii')).base(16);</lang>

Output:
414FA339

Phix

Included as demo\rosetta\crc32.exw, which also includes a thread-safe version <lang Phix>sequence table integer have_table = 0

procedure make_crc() atom rem 

   if have_table=0 then
       have_table = 1
       table = repeat(0,256)
       for i=0 to 255 do
           rem = i
           for j=1 to 8 do
               if and_bits(rem,1) then
                   rem = xor_bits(floor(rem/2),#EDB88320)
               else
                   rem = floor(rem/2)
               end if
               if rem<0 then
                   rem += #100000000
               end if
           end for
           table[i+1] = rem
       end for
   end if

end procedure

function crc32(string s) atom crc = #FFFFFFFF 

   if have_table=0 then make_crc() end if
   for i=1 to length(s) do
       crc = xor_bits(floor(crc/#100),table[xor_bits(and_bits(crc,0xff),s[i])+1])
       if crc<0 then
           crc += #100000000
       end if
   end for

-- return not_bits(crc) 

   return and_bits(not_bits(crc),#FFFFFFFF)

end function</lang> Test code: <lang Phix>string s = "The quick brown fox jumps over the lazy dog" printf(1,"The CRC of %s is %08x\n",{s,crc32(s)})</lang>

Output:
The CRC of The quick brown fox jumps over the lazy dog is 414FA339

PHP

PHP has a built-in function crc32.

<lang php>printf("%x\n", crc32("The quick brown fox jumps over the lazy dog"));</lang> 

414fa339

PL/I

<lang pli>*process source attributes xref or(!) nest; 

crct: Proc Options(main);
/*********************************************************************
* 19.08.2013 Walter Pachl  derived from REXX
*********************************************************************/
Dcl (LEFT,LENGTH,RIGHT,SUBSTR,UNSPEC) Builtin;
Dcl SYSPRINT Print;
dcl tab(0:255) Bit(32);
Call mk_tab;
Call crc_32('The quick brown fox jumps over the lazy dog');
Call crc_32('Generate CRC32 Checksum For Byte Array Example');

crc_32: Proc(s);
/*********************************************************************
* compute checksum for s
*********************************************************************/
Dcl s Char(*);
Dcl d   Bit(32);
Dcl d1  Bit( 8);
Dcl d2  Bit(24);
Dcl cc  Char(1);
Dcl ccb Bit(8);
Dcl tib Bit(8);
Dcl ti  Bin Fixed(16) Unsigned;
Dcl k   Bin Fixed(16) Unsigned;
d=(32)'1'b;
Do k=1 To length(s);
   d1=right(d,8);
   d2=left(d,24);
   cc=substr(s,k,1);
   ccb=unspec(cc);
   tib=d1^ccb;
   Unspec(ti)=tib;
   d='00000000'b!!d2^tab(ti);
   End;
 d=d^(32)'1'b;
 Put Edit(s,'CRC_32=',b2x(d))(Skip,a(50),a,a);
 Put Edit('decimal ',b2d(d))(skip,x(49),a,f(10));
End;

b2x: proc(b) Returns(char(8));
dcl b bit(32);
dcl b4 bit(4);
dcl i Bin Fixed(31);
dcl r Char(8) Var init();
Do i=1 To 29 By 4;
  b4=substr(b,i,4);
  Select(b4);
    When('0000'b) r=r!!'0';
    When('0001'b) r=r!!'1';
    When('0010'b) r=r!!'2';
    When('0011'b) r=r!!'3';
    When('0100'b) r=r!!'4';
    When('0101'b) r=r!!'5';
    When('0110'b) r=r!!'6';
    When('0111'b) r=r!!'7';
    When('1000'b) r=r!!'8';
    When('1001'b) r=r!!'9';
    When('1010'b) r=r!!'A';
    When('1011'b) r=r!!'B';
    When('1100'b) r=r!!'C';
    When('1101'b) r=r!!'D';
    When('1110'b) r=r!!'E';
    When('1111'b) r=r!!'F';
    End;
  End;
Return(r);
End;

b2d: Proc(b) Returns(Dec Fixed(15));
Dcl b Bit(32);
Dcl r Dec Fixed(15) Init(0);
Dcl i Bin Fixed(16);
Do i=1 To 32;
  r=r*2
  If substr(b,i,1) Then
    r=r+1;
  End;
Return(r);
End;

mk_tab: Proc;
dcl b32 bit(32);
dcl lb  bit( 1);
dcl ccc bit(32) Init('edb88320'bx);
dcl (i,j) Bin Fixed(15);
Do i=0 To 255;
  b32=(24)'0'b!!unspec(i);
  Do j=0 To 7;
    lb=right(b32,1);
    b32='0'b!!left(b32,31);
    If lb='1'b Then
      b32=b32^ccc;
    End;
  tab(i)=b32;
  End;
End;
End;</lang>
Output:
The quick brown fox jumps over the lazy dog       CRC_32=414FA339
                                                 decimal 1095738169
Generate CRC32 Checksum For Byte Array Example    CRC_32=D1370232
                                                 decimal 3510043186

PicoLisp

Library and implementation.

<lang PicoLisp>(setq *Table 

  (mapcar
     '((N)
        (do 8
           (setq N
              (if (bit? 1 N)
                 (x| (>> 1 N) `(hex "EDB88320"))
                 (>> 1 N) ) ) ) )
     (range 0 255) ) )

(de crc32 (Lst) 

  (let Crc `(hex "FFFFFFFF")
     (for I (chop Lst)
        (setq Crc
           (x|
              (get
                 *Table
                 (inc (x| (& Crc 255) (char I))) )
              (>> 8 Crc) ) ) )
     (x| `(hex "FFFFFFFF") Crc) ) )

(let Str "The quick brown fox jumps over the lazy dog" 

  (println (hex (crc32 Str)))
  (println
     (hex (native "libz.so" "crc32" 'N 0 Str (length Str))) ) )

(bye)</lang>

PureBasic

Works with: PB Version 5.40

<lang PureBasic> a$="The quick brown fox jumps over the lazy dog"

UseCRC32Fingerprint() : b$=StringFingerprint(a$, #PB_Cipher_CRC32)

OpenConsole() PrintN("CRC32 Cecksum [hex] = "+UCase(b$)) PrintN("CRC32 Cecksum [dec] = "+Val("$"+b$)) Input()

End</lang>

Output:
CRC32 Cecksum [hex] = 414FA339
CRC32 Cecksum [dec] = 1095738169

Python

Library

zlib.crc32 and binascii.crc32 give identical results.

<lang python>>>> s = 'The quick brown fox jumps over the lazy dog' >>> import zlib >>> hex(zlib.crc32(s)) '0x414fa339'

>>> import binascii >>> hex(binascii.crc32(s)) '0x414fa339'</lang>

If you have Python 2.x, these functions might return a negative integer; you would need to use & 0xffffffff to get the same answer as Python 3.x. With Python 3.x, convert first the string to bytes, for instance with s.encode('UTF-8'), as these functions do not accept strings.

Implementation

<lang python>def create_table(): 

   a = []
   for i in range(256):
       k = i
       for j in range(8):
           if k & 1:
               k ^= 0x1db710640
           k >>= 1
       a.append(k)
   return a

def crc_update(buf, crc): 

   crc ^= 0xffffffff
   for k in buf:
       crc = (crc >> 8) ^ crc_table[(crc & 0xff) ^ k]
   return crc ^ 0xffffffff

crc_table = create_table() print(hex(crc_update(b"The quick brown fox jumps over the lazy dog", 0)))</lang>

Or, more declaratively (without mutation, using map, reduce and iterate):

<lang Python>from functools import (reduce) from itertools import (islice)


  1. main :: IO ()

def main(): 

   print (
       format(crc32('The quick brown fox jumps over the lazy dog'), '02x')
   )


  1. crc32 :: String -> Int

def crc32(s): 

   table = list(
       map(lambda n: list(
           islice(
               iterate(
                   lambda x: (
                       (lambda z: 0xEDB88320 ^ z) if x & 1 else (lambda z: z)
                   )(x >> 1)
               )(n), 9)
       )[8], list(range(0, 256)))
   )
   return reduce(
       lambda a, c: (a >> 8) ^ table[
           (a ^ ord(c)) & 0xff
       ],
       list(s), (0xffffffff)
   ) ^ 0xffffffff


  1. GENERIC ABSTRACTIONS ------------------------------------


  1. iterate :: (a -> a) -> a -> Gen [a]

def iterate(f): 

   def go(x):
       v = x
       while True:
           yield(v)
           v = f(v)
   return lambda x: go(x)


main()</lang>

Output:
414fa339

Racket

<lang racket>

  1. lang racket

(define (bytes-crc32 data) 

 (bitwise-xor
  (for/fold ([accum #xFFFFFFFF])
    ([byte  (in-bytes data)])
    (for/fold ([accum (bitwise-xor accum byte)])
      ([num (in-range 0 8)])
      (bitwise-xor (quotient accum 2)
                   (* #xEDB88320 (bitwise-and accum 1)))))
  #xFFFFFFFF))

(define (crc32 s) 

 (bytes-crc32 (string->bytes/utf-8 s)))

(format "~x" (crc32 "The quick brown fox jumps over the lazy dog")) </lang>

Output:

<lang racket> "414fa339" </lang>

REXX

<lang rexx>/*REXX program computes the CRC─32 (32 bit Cyclic Redundancy Check) checksum for a */ /*─────────────────────────────────given string [as described in ISO 3309, ITU─T V.42].*/ call show 'The quick brown fox jumps over the lazy dog' /*the 1st string.*/ call show 'Generate CRC32 Checksum For Byte Array Example' /* " 2nd " */ exit /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ CRC_32: procedure; parse arg !,$; c='edb88320'x /*2nd arg used for repeated invocations*/ 

                                  f='ffFFffFF'x /* [↓]  build an  8─bit  indexed table,*/
           do i=0  for 256;       z=d2c(i)      /*                  one byte at a time.*/
           r=right(z, 4, '0'x)                  /*insure the  "R"   is thirty-two bits.*/
                                                /* [↓]  handle each rightmost byte bit.*/
             do j=0  for 8;      rb=x2b(c2x(r)) /*handle each bit of rightmost 8 bits. */
             r=x2c(b2x(0 || left(rb, 31)))      /*shift it right (an unsigned)  1  bit.*/
             if right(rb,1)  then r=bitxor(r,c) /*this is a bin bit for XOR grunt─work.*/
             end    /*j*/
           !.z=r                                /*assign to an eight─bit index table.  */
           end      /*i*/

       $=bitxor(word($ '0000000'x, 1), f)       /*utilize the user's CRC or a default. */
           do k=1  for length(!)                /*start number crunching the input data*/
           ?=bitxor(right($,1), substr(!,k,1))
           $=bitxor('0'x || left($, 3),  !.?)
           end   /*k*/
       return $                                 /*return with cyclic redundancy check. */

/*──────────────────────────────────────────────────────────────────────────────────────*/ show: procedure; parse arg Xstring; numeric digits 12; say; say 

       checksum=CRC_32(Xstring)                       /*invoke  CRC_32 to create a CRC.*/
       checksum=bitxor(checksum, 'ffFFffFF'x)         /*final convolution for checksum.*/
       say center(' input string [length of' length(Xstring) "bytes] ", 79, '═')
       say Xstring                                    /*show the string on its own line*/
       say                                            /*↓↓↓↓↓↓↓↓↓↓↓↓  is fifteen blanks*/
       say  "hex CRC-32 checksum ="   c2x(checksum)     left(, 15),
            "dec CRC-32 checksum ="   c2d(checksum)   /*show the CRC-32 in hex and dec.*/
       return</lang>

output 

══════════════════════ input string [length of 43 bytes] ══════════════════════
The quick brown fox jumps over the lazy dog

hex CRC-32 checksum = 414FA339                 dec CRC-32 checksum = 1095738169


══════════════════════ input string [length of 46 bytes] ══════════════════════
Generate CRC32 Checksum For Byte Array Example

hex CRC-32 checksum = D1370232                 dec CRC-32 checksum = 3510043186

Ruby

Use 'zlib' from standard library.

<lang ruby>require 'zlib' printf "0x%08x\n", Zlib.crc32('The quick brown fox jumps over the lazy dog')

  1. => 0x414fa339</lang>

Reimplement CRC-32 in Ruby, with comments to show the polynomials.

<lang ruby>module CRC 

 # Divisor is a polynomial of degree 32 with coefficients modulo 2.
 # We store Divisor in a 33-bit Integer; the polynomial is
 #   Divisor[32] + Divisor[31] * x + ... + Divisor[0] * x**32
 Divisor = [0, 1, 2, 4, 5, 7, 8, 10, 11, 12, 16, 22, 23, 26, 32] \
   .inject(0) {|sum, exponent| sum + (1 << (32 - exponent))}

 # This table gives the crc (without conditioning) of every possible
 # _octet_ from 0 to 255. Each _octet_ is a polynomial of degree 7,
 #   octet[7] + octet[6] * x + ... + octet[0] * x**7
 # Then remainder = Table[octet] is the remainder from
 # _octet_ times x**32 divided by Divisor,
 #   remainder[31] + remainder[30] + ... + remainder[0] * x**31
 Table = Array.new(256) do |octet|
   # Find remainder from polynomial long division.
   #    octet[ 7] * x**32 + ... +   octet[0] * x**39
   #  Divisor[32] * x**0  + ... + Divisor[0] * x**32
   remainder = octet
   (0..7).each do |i|
     # Find next term of quotient. To simplify the code,
     # we assume that Divisor[0] is 1, and we only check
     # remainder[i]. We save remainder, forget quotient.
     if remainder[i].zero?
       # Next term of quotient is 0 * x**(7 - i).
       # No change to remainder.
     else
       # Next term of quotient is 1 * x**(7 - i). Multiply
       # this term by Divisor, then subtract from remainder.
       #  * Multiplication uses left shift :<< to align
       #    the x**(39 - i) terms.
       #  * Subtraction uses bitwise exclusive-or :^.
       remainder ^= (Divisor << i)
     end
   end
   remainder >> 8      # Remove x**32 to x**39 terms.
 end

 module_function

 def crc32(string, crc = 0)
   # Pre-conditioning: Flip all 32 bits. Without this step, a string
   # preprended with extra "\0" would have same crc32 value.
   crc ^= 0xffff_ffff

   # Iterate octets to perform polynomial long division.
   string.each_byte do |octet|

     # Update _crc_ by continuing its polynomial long division.
     # Our current remainder is old _crc_ times x**8, plus
     # new _octet_ times x**32, which is
     #   crc[32] * x**8 + crc[31] * x**9 + ... + crc[8] * x**31 \
     #     + (crc[7] + octet[7]) * x**32 + ... \
     #     + (crc[0] + octet[0]) * x**39
     #
     # Our new _crc_ is the remainder from this polynomial divided by
     # Divisor. We split the terms into part 1 for x**8 to x**31, and
     # part 2 for x**32 to x**39, and divide each part separately.
     # Then remainder 1 is trivial, and remainder 2 is in our Table.

     remainder_1 = crc >> 8
     remainder_2 = Table[(crc & 0xff) ^ octet]

     # Our new _crc_ is sum of both remainders. (This sum never
     # overflows to x**32, so is not too big for Divisor.)
     crc = remainder_1 ^ remainder_2
   end

   # Post-conditioning: Flip all 32 bits. If we later update _crc_,
   # this step cancels the next pre-conditioning.
   crc ^ 0xffff_ffff
 end

end

printf "0x%08x\n", CRC.crc32("The quick brown fox jumps over the lazy dog")

  1. => 0x414fa339</lang>

Rust

This does not perform any caching of the lookup table for simplicity. <lang rust> fn crc32_compute_table() -> [u32; 256] { 

   let mut crc32_table = [0; 256];

   for n in 0..256 {
       crc32_table[n as usize] = (0..8).fold(n as u32, |acc, _| {
           match acc & 1 {
               1 => 0xedb88320 ^ (acc >> 1),
               _ => acc >> 1,
           }
       });
   }

   crc32_table

}

fn crc32(buf: &str) -> u32 { 

   let crc_table = crc32_compute_table();

   !buf.bytes().fold(!0, |acc, octet| {
       (acc >> 8) ^ crc_table[((acc & 0xff) ^ octet as u32) as usize]
   })

}

fn main() { 

   println!("{:x}", crc32("The quick brown fox jumps over the lazy dog"));

} </lang>

Output:
414fa339

Scala

Translation of: Java

<lang scala>import java.util.zip.CRC32 val crc=new CRC32 crc.update("The quick brown fox jumps over the lazy dog".getBytes) println(crc.getValue.toHexString) //> 414fa339</lang>

Seed7

<lang seed7>$ include "seed7_05.s7i"; 

 include "crc32.s7i";

const proc: main is func 

 begin
   writeln(ord(crc32("The quick brown fox jumps over the lazy dog")) radix 16 lpad0 8);
 end func;</lang>
Output:
414fa339

Smalltalk

Works with: Smalltalk/X

the CRC32Stream utility class can do it for me: <lang smalltalk>CRC32Stream hashValueOf:'The quick brown fox jumps over the lazy dog'</lang>

Output:
1095738169 "which is 16r414FA339"

Swift

Using the zlib crc32 function available to Swift from libz.dylib. <lang Swift>import Foundation

let strData = "The quick brown fox jumps over the lazy dog".dataUsingEncoding(NSUTF8StringEncoding, 

   allowLossyConversion: false)

let crc = crc32(uLong(0), UnsafePointer<Bytef>(strData!.bytes), uInt(strData!.length))

println(NSString(format:"%2X", crc))</lang>

Output:
414FA339

Tcl

<lang tcl>package require Tcl 8.6

set data "The quick brown fox jumps over the lazy dog" puts [format "%x" [zlib crc32 $data]]</lang>

Output:
414fa339

Alternatively, with older versions of Tcl:

Library: Tcllib (Package: crc32)

<lang tcl>package require crc32 puts [format "%x" [crc::crc32 $data]]</lang> With the same input data, it produces identical output.

VAX Assembly

<lang VAX Assembly> EDB88320 0000 1 poly: .long ^xedb88320 ;crc32 

                          00000044  0004     2 table:  .blkl   16
                                    0044     3 
        4C 58 21 0000004C'010E0000' 0044     4 fmt:    .ascid  "!XL"                           ;result format

36 35 34 33 32 31 00000057'010E0000' 004F 5 result: .ascid "12345678"  ; and buffer 

                             38 37  005D       
                              0000  005F     6 .entry  crc,0
                        A0 AF   7F  0061     7         pushaq  table                           ;fill table
                        99 AF   DF  0064     8         pushal  poly                            ; for
             00000000'GF   02   FB  0067     9         calls   #2, g^lib$crc_table             ;  crc opcode
     2B'  FFFFFFFF 8F   93 AF   0B  006E    10         crc     table, #-1, s^#len, b^msg       ;table,init,len,string
                        98'AF       0077       
                      50   50   D2  0079    11         mcoml   r0, r0                          ;invert result
                                    007C    12         $fao_s	ctrstr = fmt, outbuf = result, p1 = r0 ; format
                        BF AF   7F  008D    13 	pushaq	result				;and show
             00000000'GF   01   FB  0090    14         calls   #1, g^lib$put_output            ;  result 414fa339
                                04  0097    15         ret
                                    0098    16

72 62 20 6B 63 69 75 71 20 65 68 54 0098 17 msg: .ascii "The quick brown fox jumps over the lazy dog" 70 6D 75 6A 20 78 6F 66 20 6E 77 6F 00A4 6C 20 65 68 74 20 72 65 76 6F 20 73 00B0 

              67 6F 64 20 79 7A 61  00BC       
                          0000002B  00C3    18 len = .-msg
                                    00C3    19 .end	crc</lang>

Visual Basic .NET

Allows the resumption of calculations, useful for processing a large file with a series of buffer reads. <lang vbnet>Public Class Crc32 

   ' Table for pre-calculated values.
   Shared table(255) As UInteger

   ' Initialize table
   Shared Sub New()
       For i As UInteger = 0 To table.Length - 1
           Dim te As UInteger = i ' table entry
           For j As Integer = 0 To 7
               If (te And 1) = 1 Then te = (te >> 1) Xor &HEDB88320UI Else te >>= 1
           Next
           table(i) = te
       Next
   End Sub

   ' Return checksum calculation for Byte Array,
   '  optionally resuming (used when breaking a large file into read-buffer-sized blocks).
   ' Call with Init = False to continue calculation.
   Public Shared Function cs(BA As Byte(), Optional Init As Boolean = True) As UInteger
       Static crc As UInteger
       If Init Then crc = UInteger.MaxValue
       For Each b In BA
           crc = (crc >> 8) Xor table((crc And &HFF) Xor b)
       Next
       Return Not crc
   End Function

End Class</lang> Test: <lang vbnet> ' Returns a Byte Array from a string of ASCII characters. 

   Function Str2BA(Str As String) As Byte()
       Return System.Text.Encoding.ASCII.GetBytes(Str)
   End Function

   ' Returns a Hex string from an UInteger, formatted to a number of digits,
   '  adding leading zeros If necessary.
   Function HexF(Value As UInteger, Digits As Integer) As String
       HexF = Hex(Value)
       If Len(HexF) < Digits Then HexF = StrDup(Digits - Len(HexF), "0") & HexF
   End Function

   ' Tests Crc32 class
   Sub Test()
       Dim Str As String = "The quick brown fox jumps over the lazy dog"
       Debug.Print("Input = """ & Str & """")
       ' Convert string to Byte Array, compute crc32, and display formatted result
       Debug.Print("Crc32 = " & HexF(Crc32.cs(Str2BA(Str)), 8))
       ' This next code demonstrates continuing a crc32 calculation when breaking the input
       ' into pieces, such as processing a large file by a series of buffer reads.
       Crc32.cs(Str2BA(Mid(Str, 1, 20)))
       Debug.Print("Crc32 = " & HexF(Crc32.cs(Str2BA(Mid(Str, 21)), False), 8))
   End Sub</lang>

Output: <lang>Input = "The quick brown fox jumps over the lazy dog" Crc32 = 414FA339 Crc32 = 414FA339</lang>

XPL0

<lang XPL0>code HexOut=27; \intrinsic routine string 0; \use zero-terminated strings

func CRC32(Str, Len); \Return CRC-32 for given string char Str; int Len; \byte array, number of bytes int I, J, R, C; [R:= -1; \initialize with all 1's for J:= 0 to Len-1 do 

   [C:= Str(J);
   for I:= 0 to 8-1 do \for each bit in byte...
       [if (R xor C) and 1 then R:= R>>1 xor $EDB88320
       else R:= R>>1;
       C:= C>>1;
       ];
   ];

return not R; ];

HexOut(0, CRC32("The quick brown fox jumps over the lazy dog", 43))</lang>

Output:
414FA339

zkl

Using zlib: <lang zkl>var [const] ZLib=Import("zeelib"); ZLib.calcCRC32(Data(Void,"The quick brown fox jumps over the lazy dog")); //-->0x414fa339</lang>

Retrieved from "https://rosettacode.org/wiki/CRC-32?oldid=207918"
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