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{{task|Checksums}} [[Category:Checksums]] {{omit from|GUISS}} {{omit from|Lilypond}} {{omit from|TPP}}
;Task: Demonstrate a method of deriving the [[wp:Computation of cyclic redundancy checks|Cyclic Redundancy Check]] from within the language.
The result should be in accordance with ISO 3309, [http://www.itu.int/rec/T-REC-V.42-200203-I/en ITU-T V.42], [http://tools.ietf.org/html/rfc1952 Gzip] and [http://www.w3.org/TR/2003/REC-PNG-20031110/ PNG].
Algorithms are described on [[wp:Cyclic redundancy check|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
11l
{{trans|C}}
V crc_table = [0] * 256
L(i) 256
UInt32 rem = i
L 8
I rem [&] 1
rem >>= 1
rem (+)= EDB8'8320
E
rem >>= 1
crc_table[i] = rem
F crc32(buf, =crc = UInt32(0))
crc = (-)crc
L(k) buf
crc = (crc >> 8) (+) :crc_table[(crc [&] 00'FF) (+) k.code]
R (-)crc
print(hex(crc32(‘The quick brown fox jumps over the lazy dog’)))
{{out}}
414FA339
Ada
{{works with|GNAT}}
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;
{{out}}
16#414FA339#
ALGOL 68
[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))
{{out}}
CRC32 OF The quick brown fox jumps over the lazy dog is: 0414fa339
AutoHotkey
DllCall / WinAPI
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")
{{out}}
0x414fa339
Implementation
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")
{{out}}
0x414fa339
C
Library
Using [http://www.stillhq.com/gpg/source-modified-1.0.3/zlib/crc32.html zlib's crc32]:
#include <stdio.h>
#include <string.h>
#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;
}
Implementation
This code is a translation from [[{{FULLPAGENAME}}#Ruby|Ruby]], with an adjustment to use 32-bit integers. This code happens to resemble the examples from [http://tools.ietf.org/html/rfc1952#section-8 RFC 1952 section 8] and from [http://www.w3.org/TR/2003/REC-PNG-20031110/#D-CRCAppendix PNG annex D], because those examples use an identical table.
#include <inttypes.h>
#include <stdio.h>
#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;
}
C++
#include <algorithm>
#include <array>
#include <cstdint>
#include <numeric>
// These headers are only needed for main(), to demonstrate.
#include <iomanip>
#include <iostream>
#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';
}
{{out}}
414fa339
"The quick brown fox jumps over the lazy dog"
(to hex ...)
54686520717569636B2062726F776E20666F78206A756D7073206F76657220746865206C617A7920646F67 414FA339
[other useful test vectors]
0000000000000000000000000000000000000000000000000000000000000000 190A55AD
FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF FF6CAB0B
000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F 91267E8A
{{libheader|boost}}
#include <boost\crc.hpp>
#include <string>
#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;
}
{{out}}
Checksum: 414fa339
C#
/// <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
}
Test:
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"));
{{out}} 414fa339
Clojure
{{trans|Java}}
(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))))
{{out}}
CRC-32('The quick brown fox jumps over the lazy dog') = 414fa339
COBOL
{{works with|GnuCOBOL}} {{libheader|zlib}}
*> 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.
{{out}}
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).
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
Test:
console.log (crc32 'The quick brown fox jumps over the lazy dog').toString 16
Output:
## Common Lisp
{{libheader|Ironclad}}
```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)
{{out}}
"414fa339"
Component Pascal
BlackBox Component Builder
Require ZLib Subsystem
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.
Execute: ^Q BbtComputeCRC32.Do
{{out}}
0414FA339%16
D
void main() {
import std.stdio, std.digest.crc;
"The quick brown fox jumps over the lazy dog"
.crc32Of.crcHexString.writeln;
}
{{out}}
414FA339
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")
{{out}}
414FA339
Erlang
Using the built-in crc32 implementation.
-module(crc32).
-export([test/0]).
test() ->
io:fwrite("~.16#~n",[erlang:crc32(<<"The quick brown fox jumps over the lazy dog">>)]).
{{out}}
16#414FA339
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 [https://github.com/slavapestov/factor/blob/master/core/checksums/crc32/crc32.factor core/checksums/crc32/crc32.factor].
FBSL
#APPTYPE CONSOLE
PRINT HEX(CHECKSUM("The quick brown fox jumps over the lazy dog"))
PAUSE
{{out}}
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.
: 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
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
FreeBASIC
{{trans|C}}
' 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
{{out}}
input = The quick brown fox jumps over the lazy dog
The CRC-32 checksum = 414FA339
Go
Library
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)
}
{{out}}
414FA339
Implementation
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"))
}
{{out}}
414fa339
Groovy
def crc32(byte[] bytes) {
new java.util.zip.CRC32().with { update bytes; value }
}
Testing:
assert '414FA339' == sprintf('%04X', crc32('The quick brown fox jumps over the lazy dog'.bytes))
Haskell
Pure 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"
{{Out}}
414fa339
Using the zlib C library ( compile with "ghc -lz file.hs"):
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 ""
{{Out}}
414fa339
=={{header|Icon}} and {{header|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.
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
{{libheader|Icon Programming Library}} [http://www.cs.arizona.edu/icon/library/src/procs/hexcvt.icn hexcvt.icn] (provides hex and hexstring) [http://www.cs.arizona.edu/icon/library/src/procs/printf.icn printf.icn] (provides formatting)
{{out}}
crc("The quick brown fox jumps over the lazy dog")=414FA339 - implementation is correct
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
Other possible representations of this result:
(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
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( ) ) + " !" ) ;
}
}
{{out}}
The CRC-32 value is : 414fa339 !
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
);
})();
{{Out}}
414fa339
Jsish
From the shell
# Util.crc32('The quick brown fox jumps over the lazy dog').toString(16);
{{out}}
"414fa339"
Julia
Using the zlib Library
using Libz
println(string(Libz.crc32(UInt8.(b"The quick brown fox jumps over the lazy dog")), base=16))
{{out}}
414fa339
Source Implementation
{{works with|Julia|0.6}}
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))
{{out}}
Message: The quick brown fox jumps over the lazy dog
Checksum: 414fa339
Kotlin
// 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)}")
}
}
{{out}}
The CRC-32 checksum of 'The quick brown fox jumps over the lazy dog' = 414fa339
Lingo
Pure 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"
Implementation:
--****************************************************************************
-- @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
===Using an "Xtra" (=binary plugin)===
cx = Xtra("Crypto").new()
put cx.cx_crc32_string("The quick brown fox jumps over the lazy dog")
-- "414fa339"
Lua
Using Library
[https://github.com/brimworks/lua-zlib zlib.crc32]
local compute=require"zlib".crc32()
local sum=compute("The quick brown fox jumps over the lazy dog")
print(string.format("0x%x", sum))
{{out}} 0x414fa339
M2000 Interpreter
Using Code
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$, i+1, 1)))))
Next i
=0xFFFFFFFF-crc
}
Print crc32("The quick brown fox jumps over the lazy dog")=0x414fa339
}
CheckIt
Using Api
Module CheckApi {
Declare CRC32 LIB "ntdll.RtlComputeCrc32" {Long Zero, a$, long s}
a$=Str$("The quick brown fox jumps over the lazy dog")
l=len(a$)*2
Hex Uint(CRC32(0,a$,l))
}
CheckApi
=={{header|Mathematica}} / {{header|Wolfram Language}}==
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"]
]
{{out}}
The CRC32 hash code of "The quick brown fox jumps over the lazy dog" is 414fa339.
Neko
The NekoVM is a 31 bit machine; 30 signed. Loadable primitives handle 32bit integers. The zlib library API exposes a CRC-32 function, that expects and returns Int32.
/**
<doc>CRC32 in Neko</doc>
**/
var int32_new = $loader.loadprim("std@int32_new", 1)
var update_crc32 = $loader.loadprim("zlib@update_crc32", 4)
var crc = int32_new(0)
var txt = "The quick brown fox jumps over the lazy dog"
crc = update_crc32(crc, txt, 0, $ssize(txt))
$print(crc, "\n")
{{out}}
prompt$ nekoc crc32.neko
prompt$ neko crc32.n
1095738169
prompt$ dc -e "$(neko crc32.n) 16op"
414FA339
NetRexx
{{trans|Java}}
/* 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
{{out}}
The CRC-32 value is : 414fa339 !
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
# 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)
{{out}}
414FA339
Objeck
class CRC32 {
function : Main(args : String[]) ~ Nil {
"The quick brown fox jumps over the lazy dog"->ToByteArray()->CRC32()->PrintLine();
}
}
{{out}}
1095738169
=={{header|Oberon-2}}== {{Works with|oo2c Version 2}}
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.
{{out}}
414FA339
OCaml
{{libheader|camlzip}}
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
Running this code in interpreted mode:
$ 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.
/* 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
{{out}}
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) {{libheader|libz.so}}
install("crc32", "lLsL", "crc32", "libz.so");
s = "The quick brown fox jumps over the lazy dog";
printf("%0x\n", crc32(0, s, #s))
Output:
414fa339
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( ) ;
{{out}}
The checksum is 414fa339
Perl 6
Call to native function crc32 in zlib
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');
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.
{{out}}
414fa339
Pure Perl 6
A fairly generic implementation with no regard to execution speed:
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);
{{out}}
414FA339
Phix
Included as demo\rosetta\crc32.exw, which also includes a thread-safe version
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
Test code:
string s = "The quick brown fox jumps over the lazy dog"
printf(1,"The CRC of %s is %08x\n",{s,crc32(s)})
{{out}}
The CRC of The quick brown fox jumps over the lazy dog is 414FA339
PHP
PHP has a built-in function [http://us2.php.net/manual/en/function.crc32.php crc32].
printf("%x\n", crc32("The quick brown fox jumps over the lazy dog"));
414fa339
PL/I
*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;
{{out}}
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.
(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)
PowerBASIC
#COMPILE EXE
#DIM ALL
#COMPILER PBCC 6
' ***********
FUNCTION CRC32(BYVAL p AS BYTE PTR, BYVAL NumBytes AS DWORD) AS DWORD
STATIC LUT() AS DWORD
LOCAL i, j, k, crc AS DWORD
IF ARRAYATTR(LUT(), 0) = 0 THEN
REDIM LUT(0 TO 255)
FOR i = 0 TO 255
k = i
FOR j = 0 TO 7
IF (k AND 1) THEN
SHIFT RIGHT k, 1
k XOR= &HEDB88320
ELSE
SHIFT RIGHT k, 1
END IF
NEXT j
LUT(i) = k
NEXT i
END IF
crc = &HFFFFFFFF
FOR i = 0 TO NumBytes - 1
k = (crc AND &HFF& XOR @p[i])
SHIFT RIGHT crc, 8
crc XOR= LUT(k)
NEXT i
FUNCTION = NOT crc
END FUNCTION
' ***********
FUNCTION PBMAIN () AS LONG
LOCAL s AS STRING
LOCAL crc AS DWORD
s = "The quick brown fox jumps over the lazy dog"
CON.PRINT "Text: " & s
crc = CRC32(STRPTR(s), LEN(s))
CON.PRINT "CRC32: " & HEX$(crc)
END FUNCTION
{{out}}
Text: The quick brown fox jumps over the lazy dog
CRC32: 414FA339
PureBasic
{{works with|PB Version 5.40}}
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
{{out}}
CRC32 Cecksum [hex] = 414FA339
CRC32 Cecksum [dec] = 1095738169
Python
Library
[http://docs.python.org/library/zlib.html#zlib.crc32 zlib.crc32] and [http://docs.python.org/library/binascii.html#binascii.crc32 binascii.crc32] give identical results.
s = 'The quick brown fox jumps over the lazy dog'
>>> import zlib
>>> hex(zlib.crc32(s))
'0x414fa339'
>>> import binascii
>>> hex(binascii.crc32(s))
'0x414fa339'
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
=Procedural=
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)))
=Composition of pure functions=
'''CRC-32 checksums for ascii strings'''
from functools import (reduce)
from itertools import (islice)
# crc32 :: String -> Int
def crc32(s):
'''CRC-32 checksum for an ASCII encoded string'''
def go(x):
x2 = x >> 1
return 0xedb88320 ^ x2 if x & 1 else x2
table = [
index(iterate(go)(n))(8)
for n in range(0, 256)
]
return reduce(
lambda a, c: (a >> 8) ^ table[
(a ^ ord(c)) & 0xff
],
list(s),
(0xffffffff)
) ^ 0xffffffff
# TEST ----------------------------------------------------
# main :: IO ()
def main():
'''Test'''
print(
format(
crc32('The quick brown fox jumps over the lazy dog'),
'02x'
)
)
# GENERIC ABSTRACTION -------------------------------------
# index (!!) :: [a] -> Int -> a
def index(xs):
'''Item at given (zero-based) index.'''
return lambda n: None if 0 > n else (
xs[n] if (
hasattr(xs, "__getitem__")
) else next(islice(xs, n, None))
)
# iterate :: (a -> a) -> a -> Gen [a]
def iterate(f):
'''An infinite list of repeated applications of f to x.'''
def go(x):
v = x
while True:
yield v
v = f(v)
return lambda x: go(x)
if __name__ == '__main__':
main()
{{Out}}
414fa339
R
digest("The quick brown fox jumps over the lazy dog","crc32", serialize=F)
{{out}}
[1] "414fa339"
Racket
#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"))
{{out}}
"414fa339"
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
'''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.
require 'zlib'
printf "0x%08x\n", Zlib.crc32('The quick brown fox jumps over the lazy dog')
# => 0x414fa339
Reimplement CRC-32 in Ruby, with comments to show the polynomials.
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")
# => 0x414fa339
Rust
This does not perform any caching of the lookup table for simplicity.
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"));
}
{{Output}}
414fa339
Scala
{{trans|Java}}
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
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;
{{out}}
414fa339
Shell
Bash
#!/usr/bin/env bash
declare -i -a CRC32_LOOKUP_TABLE
__generate_crc_lookup_table() {
local -i -r LSB_CRC32_POLY=0xEDB88320 # The CRC32 polynomal LSB order
local -i index byte lsb
for index in {0..255}; do
((byte = 255 - index))
for _ in {0..7}; do # 8-bit lsb shift
((lsb = byte & 0x01, byte = ((byte >> 1) & 0x7FFFFFFF) ^ (lsb == 0 ? LSB_CRC32_POLY : 0)))
done
((CRC32_LOOKUP_TABLE[index] = byte))
done
}
__generate_crc_lookup_table
typeset -r CRC32_LOOKUP_TABLE
crc32_string() {
[[ ${#} -eq 1 ]] || return
local -i i byte crc=0xFFFFFFFF index
for ((i = 0; i < ${#1}; i++)); do
byte=$(printf '%d' "'${1:i:1}") # Get byte value of character at i
((index = (crc ^ byte) & 0xFF, crc = (CRC32_LOOKUP_TABLE[index] ^ (crc >> 8)) & 0xFFFFFFFF))
done
echo $((crc ^ 0xFFFFFFFF))
}
printf 'The CRC32 of: %s\nis: 0x%08x\n' "${1}" "$(crc32_string "${1}")"
# crc32_string "The quick brown fox jumps over the lazy dog"
# yields 414fa339
POSIX
The POSIX Shell has no array type and no string indexation.
It costs less to recompute polynomal shift for each character than indexing
with external tools like awk or tr.
#!/bin/sh
# POSIX Shell CRC32 of string
# @Name: crc32.sh
# @Version: 1.0.0
# @Author: Léa Gris <lea.gris@noiraude.net>
# @Date: Wed, 27 Mar 2019
# @License: WTFPL http://www.wtfpl.net/
# POSIX Shell has no array or string index
# Implementing a pre-computed CRC32 byte indexed look-up table
# would cost more CPU cycles calling external tools like
# awk or tr to index records from a string.
# Computes the CRC32 of the input data stream
# <&1: The input data stream
# >&1: The CRC32 integer of the input data stream
crc32_stream() {
crc=0xFFFFFFFF # The Initial CRC32 value
p=0xedb88320 # The CRC32 polynomal
r=0 # The polynomal reminder
c='' # The current character
byte=0 # Tge byte value of the current character
# Iterates each character of the input stream
while c="$(dd bs=1 count=1 2>/dev/null)" && [ -n "$c" ]; do
byte=$(printf '%d' "'${c}") # Converts the character into its byte value
r=$(((crc & 0xff) ^ byte)) # XOR LSB of CRC with current byte
b=0 # bit index
# 8-bit lsb shift with XOR polynomal reminder when odd
while [ $((b <= 7)) -ne 0 ] && b=$((b + 1)); do
r=$(((r & 0x1) ? (r >> 1) ^ p : r >> 1))
done
crc=$(((crc >> 8) ^ r)) # XOR MSB of CRC with Reminder
done
# Output CRC32 integer XOR mask 32 bits
echo $((crc ^ 0xFFFFFFFF))
}
# Computes the CRC32 of argument string
# 1: The argument string
# >&1: The CRC32 integer of the argument string
crc32_string() {
[ $# -eq 1 ] || return # argument required
# Streams with printf to prevent postfixing the string
# with a newline, since echo -n is not available in POSIX Shell
printf '%s' "$1" | crc32_stream
}
printf 'The CRC32 of: %s\nis: %08x\n' "$1" "$(crc32_string "$1")"
# crc32_string "The quick brown fox jumps over the lazy dog"
# yields 414fa339
{{out}}
bash ./crc32.sh "The quick brown fox jumps over the lazy dog"
The CRC32 of: The quick brown fox jumps over the lazy dog
is: 0x414fa339
Smalltalk
{{works with|Smalltalk/X}} the CRC32Stream utility class can do it for me:
CRC32Stream hashValueOf:'The quick brown fox jumps over the lazy dog'
{{out}} 1095738169 "which is 16r414FA339"
Swift
Using the zlib crc32 function available to Swift from libz.dylib.
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))
{{out}}
414FA339
Tcl
package require Tcl 8.6
set data "The quick brown fox jumps over the lazy dog"
puts [format "%x" [zlib crc32 $data]]
{{out}}
414fa339
Alternatively, with older versions of Tcl: {{tcllib|crc32}}
package require crc32
puts [format "%x" [crc::crc32 $data]]
With the same input data, it produces identical output.
VAX Assembly
EDB88320 0000 1 poly: .long ^xedb88320 ;crc32
00000044 0004 2 table: .blkl 16
0044 3
4C 58 21 0000004C'010E0000' 0044 4 fmt: .ascid "!XL" ;result format
36 35 34 33 32 31 00000057'010E0000' 004F 5 result: .ascid "12345678" ; and buffer
38 37 005D
0000 005F 6 .entry crc,0
A0 AF 7F 0061 7 pushaq table ;fill table
99 AF DF 0064 8 pushal poly ; for
00000000'GF 02 FB 0067 9 calls #2, g^lib$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
Visual Basic
{{works with|Visual Basic|5}} {{works with|Visual Basic|6}} {{works with|VBA|Access 97}} {{works with|VBA|6.5}} {{works with|VBA|7.1}} {{libheader|Win32}} Not an ideal task for Visual Basic because the language lacks bit shifting operators (which can of course be emulated, but that's slow). Then again, since the only platform supported by VB is Microsoft Windows (32 Bit Subsystem), we can let the Windows API do the work for us. RtlComputeCrc32() was available since Windows XP and is still present in Windows 10.
Option Explicit
Declare Function RtlComputeCrc32 Lib "ntdll.dll" _
(ByVal dwInitial As Long, pData As Any, ByVal iLen As Long) As Long
'--------------------------------------------------------------------
Sub Main()
Dim s As String
Dim b() As Byte
Dim l As Long
s = "The quick brown fox jumps over the lazy dog"
b() = StrConv(s, vbFromUnicode) 'convert Unicode to ASCII
l = RtlComputeCrc32(0&, b(0), Len(s))
Debug.Assert l = &H414FA339
End Sub
Visual Basic .NET
Allows the resumption of calculations, useful for processing a large file with a series of buffer reads.
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
Test:
' 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
Output:
## XPL0
```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))
{{out}}
414FA339
zkl
Using zlib:
var [const] ZLib=Import("zeelib");
ZLib.calcCRC32(Data(Void,"The quick brown fox jumps over the lazy dog"));
//-->0x414fa339