Crypt::Checksum::CRC32(3)                  User Contributed Perl Documentation


NAME
       Crypt::Checksum::CRC32 - Compute CRC32 checksum

SYNOPSIS
          ### Functional interface:
          use Crypt::Checksum::CRC32 ':all';

          # calculate CRC32 checksum from string/buffer
          my $data = 'data string';
          my $checksum_raw  = crc32_data($data);
          my $checksum_hex  = crc32_data_hex($data);
          my $checksum_int  = crc32_data_int($data);
          # or from file
          my $checksum_file_raw  = crc32_file('filename.dat');
          my $checksum_file_hex  = crc32_file_hex('filename.dat');
          my $checksum_file_int  = crc32_file_int('filename.dat');
          # or from filehandle
          my $filehandle = ...; # existing binary-mode filehandle
          my $checksum_fh_raw  = crc32_file($filehandle);
          my $checksum_fh_hex  = crc32_file_hex($filehandle);
          my $checksum_fh_int  = crc32_file_int($filehandle);

          ### OO interface:
          use Crypt::Checksum::CRC32;

          my $d = Crypt::Checksum::CRC32->new;
          $d->add('any data');
          $d->add('another data');
          my $checksum_raw = $d->digest;     # raw 4 bytes
          my $checksum_hex = $d->hexdigest;  # hexadecimal form
          my $checksum_int = $d->intdigest;  # 32-bit unsigned integer

          # or checksum a file instead
          my $checksum_file_raw = Crypt::Checksum::CRC32->new->addfile('filename.dat')->digest;

DESCRIPTION
       Computes CRC-32 checksums using the ISO 3309 / ITU-T V.42 polynomial
       (0xEDB88320, also known as CRC-32/ISO-HDLC). This is the same variant
       used by Ethernet (IEEE 802.3), PKZIP, gzip, and PNG.

       Updated: v0.057

EXPORT
       Nothing is exported by default.

       You can export selected functions:

        use Crypt::Checksum::CRC32 qw(crc32_data crc32_data_hex crc32_data_int crc32_file crc32_file_hex crc32_file_int);

       Or all of them at once:

        use Crypt::Checksum::CRC32 ':all';

FUNCTIONS
   crc32_data
       Returns the checksum as raw octets.

        my $checksum_raw = crc32_data('data string');
        #or
        my $checksum_raw = crc32_data('any data', 'more data', 'even more data');

   crc32_data_hex
       Returns checksum as a hexadecimal string.

        my $checksum_hex = crc32_data_hex('data string');
        #or
        my $checksum_hex = crc32_data_hex('any data', 'more data', 'even more data');

   crc32_data_int
       Returns checksum as unsigned 32-bit integer.

        my $checksum_int = crc32_data_int('data string');
        #or
        my $checksum_int = crc32_data_int('any data', 'more data', 'even more data');

       Each "crc32_data*" function converts its data arguments to bytes using
       Perl's usual scalar stringification. Defined scalars, including numbers
       and string-overloaded objects, are accepted. "undef" is treated as an
       empty string and may emit Perl's usual "uninitialized value" warning.

   crc32_file
       Returns the checksum as raw octets.

        my $checksum_raw = crc32_file('filename.dat');
        #or
        my $filehandle = ...; # existing binary-mode filehandle
        my $checksum_raw = crc32_file($filehandle);

   crc32_file_hex
       Returns checksum as a hexadecimal string.

        my $checksum_hex = crc32_file_hex('filename.dat');
        #or
        my $filehandle = ...; # existing binary-mode filehandle
        my $checksum_hex = crc32_file_hex($filehandle);

   crc32_file_int
       Returns checksum as unsigned 32-bit integer.

        my $checksum_int = crc32_file_int('filename.dat');
        #or
        my $filehandle = ...; # existing binary-mode filehandle
        my $checksum_int = crc32_file_int($filehandle);

METHODS
       Unless noted otherwise, assume $d is an existing checksum object
       created via "new".

   new
       Constructor, returns a reference to the checksum object.

        my $d = Crypt::Checksum::CRC32->new;

   clone
       Creates a copy of the checksum object state and returns a reference to
       the copy.

        $d->clone();

   reset
       Reinitialize the checksum object state and returns a reference to the
       checksum object.

        $d->reset();

   add
       All arguments are appended to the message we calculate checksum for.
       The return value is the checksum object itself.

       Each argument is converted to bytes using Perl's usual scalar
       stringification.  Defined scalars, including numbers and
       string-overloaded objects, are accepted.  "undef" is treated as an
       empty string and may emit Perl's usual "uninitialized value" warning.

        $d->add('any data');
        #or
        $d->add('any data', 'more data', 'even more data');

   addfile
       The content of the file (or filehandle) is appended to the message we
       calculate checksum for.  The return value is the checksum object
       itself.

        $d->addfile('filename.dat');
        #or
        my $filehandle = ...; # existing binary-mode filehandle
        $d->addfile($filehandle);

       Note: The filehandle must be in binary mode before you pass it to
       addfile().

   digest
       Returns the binary checksum (raw bytes).  This method does not alter
       the object state, so you can call it repeatedly and continue with add()
       or addfile() afterwards.

        my $result_raw = $d->digest();

   hexdigest
       Returns the checksum encoded as a hexadecimal string.  Like digest(),
       this method does not alter the object state.

        my $result_hex = $d->hexdigest();

   intdigest
       Returns the checksum encoded as unsigned 32-bit integer.  Like
       digest(), this method does not alter the object state.

        my $result_int = $d->intdigest();

SEE ALSO
       o   CryptX

       o   <https://en.wikipedia.org/wiki/Cyclic_redundancy_check>

perl v5.42.2                      2026-08-10         Crypt::Checksum::CRC32(3)