From ab97942d06a3946cff48f4027740a31ceae1ad8a Mon Sep 17 00:00:00 2001
From: Tom Ryder <tom@sanctum.geek.nz>
Date: Thu, 10 Aug 2017 01:07:17 +1200
Subject: Use generic Digest module frontend

Slightly older in core, enables using MD5 if need be
---
 checkem | 33 +++++++++++++++++++--------------
 1 file changed, 19 insertions(+), 14 deletions(-)

diff --git a/checkem b/checkem
index 0035cee..96d6508 100755
--- a/checkem
+++ b/checkem
@@ -1,8 +1,10 @@
 #!/usr/bin/env perl
 
 #
-# checkem: Find groups of duplicate files with libraries that have been in Perl
-# Core since version 5.9.3
+# checkem: Find groups of duplicate files with core libraries.
+#
+# Author: Tom Ryder <tom@sanctum.geek.nz>
+# Site: <https://sanctum.geek.nz/cgit/checkem.git>
 #
 
 # Package name
@@ -13,18 +15,17 @@ use strict;
 use warnings;
 use utf8;
 
-# Get the find and current working directory modules
+# Tolerate very old Perls
+use 5.006;
+
+# Import required modules
 use Carp;
 use Fcntl ':mode';
 use File::Find;
-use Digest::SHA;
-
-# Lowest version number that has all of those core modules; Digest::SHA is the
-# newest
-use 5.009_003;
+use Digest;
 
 # Version number to make Perl::Critic happy
-our $VERSION = 2.7;
+our $VERSION = 2.8;
 
 # If no arguments, work with the current working directory
 if ( !@ARGV ) {
@@ -42,10 +43,9 @@ my %STATS = (
     size => 7,
 );
 
-# Figure out the SHA algorithm to use; defaults to sha256, but can be overriden
-# by setting CHECKEM_ALG in the environment to e.g. "sha1", which is slightly
-# faster but technically broken in practice since early 2017
-my $alg = $ENV{CHECKEM_ALG} // 'sha256';
+# Figure out the Digest algorithm to use; defaults to SHA-256, but can be
+# overriden by setting CHECKEM_ALG in the environment
+my $alg = $ENV{CHECKEM_ALG} // 'SHA-256';
 
 # Start a hash of filesizes to file names/stats...
 my %sizes;
@@ -96,7 +96,12 @@ for my $fs ( grep { @{$_} > 1 } values %sizes ) {
 
         # Files still the same size and not hard linked, group by digest;
         # create the digest object if it isn't already defined
-        ( $dig //= Digest::SHA->new($alg) )->addfile( $f->{name} );
+        open my $fh, '<', $f->{name}
+          or croak 'Failed to open file';
+        binmode $fh;
+        ( $dig //= Digest->new($alg) )->addfile($fh);
+        close $fh
+          or croak 'Failed to close file';
         push @{ $sums{ $dig->digest() } }, $f;
     }
 }
-- 
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