package Crypt::Digest;

use strict;
use warnings;
our $VERSION = '0.091';

require Exporter; our @ISA = qw(Exporter); ### use Exporter 5.57 'import';
our %EXPORT_TAGS = ( all => [qw( digest_data digest_data_hex digest_data_b64 digest_data_b64u digest_file digest_file_hex digest_file_b64 digest_file_b64u )] );
our @EXPORT_OK = ( @{ $EXPORT_TAGS{'all'} } );
our @EXPORT = qw();

use Carp;
$Carp::Internal{(__PACKAGE__)}++;
use CryptX;

### the following methods/functions are implemented in XS:
# - new
# - hashsize
# - clone
# - reset
# - digest
# - hexdigest
# - b64digest
# - add
# - digest_data
# - digest_data_hex
# - digest_data_b64
# - digest_data_b64u
# - DESTROY

### METHODS

sub addfile {
  my ($self, $file) = @_;

  my ($handle, $close_handle);
  if (ref($file) && eval { defined fileno($file) }) {
    $handle = $file;
  }
  elsif (defined($file) && !ref($file)) {
    open($handle, "<", $file) || croak "FATAL: cannot open '$file': $!";
    binmode($handle);
    $close_handle = 1;
  }
  else {
    croak "FATAL: invalid handle";
  }

  my $n;
  my $buf = "";
  {
    local $SIG{__DIE__} = \&CryptX::_croak;
    while (($n = read($handle, $buf, 32*1024))) {
      $self->add($buf)
    }
    croak "FATAL: read failed: $!" unless defined $n;
  }
  close($handle) if $close_handle;

  return $self;
}

sub CLONE_SKIP { 1 } # prevent cloning

### FUNCTIONS

sub digest_file        { local $SIG{__DIE__} = \&CryptX::_croak; Crypt::Digest->new(shift)->addfile(@_)->digest     }
sub digest_file_hex    { local $SIG{__DIE__} = \&CryptX::_croak; Crypt::Digest->new(shift)->addfile(@_)->hexdigest  }
sub digest_file_b64    { local $SIG{__DIE__} = \&CryptX::_croak; Crypt::Digest->new(shift)->addfile(@_)->b64digest  }
sub digest_file_b64u   { local $SIG{__DIE__} = \&CryptX::_croak; Crypt::Digest->new(shift)->addfile(@_)->b64udigest }

1;

=pod

=head1 NAME

Crypt::Digest - Generic interface to hash/digest functions

=head1 SYNOPSIS

   ### Functional interface:
   use Crypt::Digest qw( digest_data digest_data_hex digest_data_b64 digest_data_b64u
                         digest_file digest_file_hex digest_file_b64 digest_file_b64u );

   my $data = 'data string';
   my $filename = 'filename.dat';
   open my $filehandle, '<:raw', $filename or die "cannot open $filename: $!";

   # calculate digest from string/buffer
   my $digest_raw  = digest_data('SHA256', $data);
   my $digest_hex  = digest_data_hex('SHA256', $data);
   my $digest_b64  = digest_data_b64('SHA256', $data);
   my $digest_b64u = digest_data_b64u('SHA256', $data);
   # calculate digest from file
   my $file_digest_raw  = digest_file('SHA256', $filename);
   my $file_digest_hex  = digest_file_hex('SHA256', $filename);
   my $file_digest_b64  = digest_file_b64('SHA256', $filename);
   my $file_digest_b64u = digest_file_b64u('SHA256', $filename);
   # calculate digest from filehandle
   my $fh_digest_raw  = digest_file('SHA256', $filehandle);

   ### OO interface:
   use Crypt::Digest;

   my $d = Crypt::Digest->new('SHA1');
   $d->add('any data');
   $d->addfile('filename.dat');
   $d->addfile($filehandle);
   my $result_raw  = $d->digest;     # raw bytes
   my $result_hex  = $d->hexdigest;  # hexadecimal form
   my $result_b64  = $d->b64digest;  # Base64 form
   my $result_b64u = $d->b64udigest; # Base64 URL-safe form

=head1 DESCRIPTION

Provides an interface to various hash/digest algorithms.

All functions and methods return raw bytes unless the method name explicitly
ends in C<_hex>, C<_b64>, or C<_b64u>. Invalid algorithm names croak.

=head1 EXPORT

Nothing is exported by default.

You can export selected functions:

  use Crypt::Digest qw( digest_data digest_data_hex digest_data_b64 digest_data_b64u
                        digest_file digest_file_hex digest_file_b64 digest_file_b64u );

Or all of them at once:

  use Crypt::Digest ':all';

=head1 FUNCTIONS

All functions take the algorithm name as the first argument. Supported values
are:

 'CHAES', 'MD2', 'MD4', 'MD5', 'RIPEMD128', 'RIPEMD160',
 'RIPEMD256', 'RIPEMD320', 'SHA1', 'SHA224', 'SHA256',
 'SHA384', 'SHA512', 'SHA512_224', 'SHA512_256', 'Tiger192', 'Whirlpool',
 'SHA3_224', 'SHA3_256', 'SHA3_384', 'SHA3_512',
 'Keccak224', 'Keccak256', 'Keccak384', 'Keccak512',
 'BLAKE2b_160', 'BLAKE2b_256', 'BLAKE2b_384', 'BLAKE2b_512',
 'BLAKE2s_128', 'BLAKE2s_160', 'BLAKE2s_224', 'BLAKE2s_256'

 (or any <NAME> for which there is a Crypt::Digest::<NAME> module)

=head2 digest_data

Joins all arguments into a single string and returns the digest for
the selected algorithm encoded as a binary string.

Data arguments are converted to byte strings using Perl's usual scalar
stringification. Defined scalars, including numbers and string-overloaded
objects, are accepted. C<undef> is treated as an empty string and may emit
Perl's usual "uninitialized value" warning. The same rules apply to
C<digest_data_hex>, C<digest_data_b64>, and C<digest_data_b64u>.

 my $digest_raw = digest_data('SHA256', 'data string');
 #or
 my $digest_raw = digest_data('SHA256', 'any data', 'more data', 'even more data');

=head2 digest_data_hex

Joins all arguments into a single string and returns the digest for
the selected algorithm encoded as a hexadecimal string.

 my $digest_hex = digest_data_hex('SHA256', 'data string');
 #or
 my $digest_hex = digest_data_hex('SHA256', 'any data', 'more data', 'even more data');

=head2 digest_data_b64

Joins all arguments into a single string and returns the digest for
the selected algorithm encoded as a Base64 string, B<with> trailing '=' padding.

 my $digest_b64 = digest_data_b64('SHA256', 'data string');
 #or
 my $digest_b64 = digest_data_b64('SHA256', 'any data', 'more data', 'even more data');

=head2 digest_data_b64u

Joins all arguments into a single string and returns the digest for
the selected algorithm encoded as a Base64 URL-safe string (see RFC 4648 section 5).

 my $digest_b64url = digest_data_b64u('SHA256', 'data string');
 #or
 my $digest_b64url = digest_data_b64u('SHA256', 'any data', 'more data', 'even more data');

=head2 digest_file

Reads a file given by a filename or filehandle and returns its digest encoded as a binary string.

 my $digest_raw = digest_file('SHA256', 'filename.dat');
 #or
 my $filehandle = ...; # existing binary-mode filehandle
 my $digest_raw = digest_file('SHA256', $filehandle);

=head2 digest_file_hex

Reads a file given by a filename or filehandle and returns its digest encoded as a hexadecimal string.

 my $digest_hex = digest_file_hex('SHA256', 'filename.dat');
 #or
 my $filehandle = ...; # existing binary-mode filehandle
 my $digest_hex = digest_file_hex('SHA256', $filehandle);

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

=head2 digest_file_b64

Reads a file given by a filename or filehandle and returns its digest encoded as a Base64 string, B<with> trailing '=' padding.

 my $digest_b64 = digest_file_b64('SHA256', 'filename.dat');
 #or
 my $filehandle = ...; # existing binary-mode filehandle
 my $digest_b64 = digest_file_b64('SHA256', $filehandle);

=head2 digest_file_b64u

Reads a file given by a filename or filehandle and returns its digest encoded as a Base64 URL-safe string (see RFC 4648 section 5).

 my $digest_b64url = digest_file_b64u('SHA256', 'filename.dat');
 #or
 my $filehandle = ...; # existing binary-mode filehandle
 my $digest_b64url = digest_file_b64u('SHA256', $filehandle);

=head1 METHODS

Unless noted otherwise, assume C<$d> is an existing digest object created via
C<new>, for example:

 my $d = Crypt::Digest->new('SHA256');

=head2 new

Constructor, returns a reference to the digest object.

 my $d = Crypt::Digest->new($name);
 # $name could be: 'CHAES', 'MD2', 'MD4', 'MD5', 'RIPEMD128', 'RIPEMD160',
 #                 'RIPEMD256', 'RIPEMD320', 'SHA1', 'SHA224', 'SHA256', 'SHA384',
 #                 'SHA512', 'SHA512_224', 'SHA512_256', 'SHA3_224', 'SHA3_256',
 #                 'SHA3_384', 'SHA3_512', 'Keccak224', 'Keccak256', 'Keccak384',
 #                 'Keccak512', 'BLAKE2b_160', 'BLAKE2b_256', 'BLAKE2b_384',
 #                 'BLAKE2b_512', 'BLAKE2s_128', 'BLAKE2s_160', 'BLAKE2s_224',
 #                 'BLAKE2s_256', 'Tiger192', 'Whirlpool'
 #
 # or any <FUNCNAME> for which there is a Crypt::Digest::<FUNCNAME> module

=head2 clone

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

 $d->clone();

=head2 reset

Resets the digest object state and returns the digest object itself.

 $d->reset();

=head2 add

Appends all arguments to the message. Returns the digest object itself.

Each argument is converted to bytes using Perl's usual scalar stringification.
Defined scalars, including numbers and string-overloaded objects, are
accepted. C<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');

Note that all the following cases are equivalent:

 # case 1
 $d->add('aa', 'bb', 'cc');

 # case 2
 $d->add('aa');
 $d->add('bb');
 $d->add('cc');

 # case 3
 $d->add('aabbcc');

 # case 4
 $d->add('aa')->add('bb')->add('cc');

=head2 addfile

Reads a file or filehandle and appends its content to the message. Returns the
digest object itself.

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

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

=head2 hashsize

Returns the length of calculated digest in bytes (e.g. 32 for SHA-256).

 $d->hashsize;
 #or
 Crypt::Digest->hashsize('SHA1');
 #or
 Crypt::Digest::hashsize('SHA1');

=head2 digest

Returns the binary digest (raw bytes).
The first call finalizes the digest object. Any later C<add()>,
C<addfile()>, C<digest()>, C<hexdigest()>, C<b64digest()>, or
C<b64udigest()> call will fail until you call C<reset()>.

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

=head2 hexdigest

Returns the digest encoded as a hexadecimal string.
Like C<digest()>, the first call finalizes the digest object.

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

=head2 b64digest

Returns the digest encoded as a Base64 string with trailing C<=> padding.
B<Note:> This padding style might differ from other C<Digest::*> modules on
CPAN.
Like C<digest()>, the first call finalizes the digest object.

 my $result_b64 = $d->b64digest();

=head2 b64udigest

Returns the digest encoded as a Base64 URL-safe string (see RFC 4648 section 5).
Like C<digest()>, the first call finalizes the digest object.

 my $result_b64url = $d->b64udigest();

=head1 SEE ALSO

=over

=item * L<CryptX>

=item * L<Crypt::Digest> tries to be compatible with the L<Digest> interface.

=item * Check subclasses like L<Crypt::Digest::SHA1>, L<Crypt::Digest::MD5>, ...

=back

=cut
