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#!/usr/bin/env perl
use Compress::Zlib;
use Digest::SHA qw(sha1_hex);
use File::Basename;
use Data::Dumper;
use strict;
use warnings;
my @filedata = <>;
my ($signature, $type, $size, $data) = read_object(join('', @filedata));
my $out = format_object($type, $data);
print "signature: $signature\ntype: $type\nsize: $size\n"
. ("-" x 40) . "\n$out\n";
sub read_object {
my ($zlib_data) = @_;
my $raw_data = uncompress($zlib_data)
|| die "Couldn't uncompress zlib data.";
my $sig = sha1_hex($raw_data);
$raw_data =~ /(.*?) (.*?)\0(.*)/s || die "Invalid object format.";
my ($type, $size, $data) = ($1, $2, $3);
warn "Size mismatch: got $size, but was actually " . length($data)
unless length($data) == $size;
($sig, $type, $size, $data);
}
sub format_object {
my ($type, $obj) = @_;
if ($type eq 'commit') {
$obj;
} elsif ($type eq 'tag') {
$obj;
} elsif ($type eq 'tree') {
format_tree($obj)
} elsif ($type eq 'blob') {
hexdump($obj);
} else {
warn "Unknown object type, showing hex representation: $type.\n";
hexdump($obj);
}
}
sub format_tree {
my ($str) = @_;
my @tree = split /\0(.{20})/, $str;
my @rc = ();
while (@tree) {
my ($info, $id) = (shift @tree, shift @tree);
$info =~ /^([^ ]*) (.*)/;
my ($mode, $name) = ($1, $2);
my @bytes = unpack('C*', $id);
my $sig = join '', map { sprintf('%02x', $_) } @bytes;
push @rc, "$mode $sig\t$name";
}
join "\n", @rc;
}
sub hexdump {
my ($str) = @_;
my ($i, $len, @chunks) = (0, length($str), ());
while ($i < $len) {
my $rem = $len - $i;
$rem = 16 unless $rem < 16;
push @chunks, substr($str, $i, $rem);
$i += $rem;
}
join "\n", map {
my @chars = unpack('C*', $_);
my @hex = map { sprintf('%02x ', $_) } @chars;
my @filtered = map { ($_ >= 040 && $_ <= 0176) ? pack('C', $_) : '.' } @chars;
my $spaces = (16 - @hex) * 3 + 4;
join('', @hex) . (' ' x $spaces) . join('', @filtered)
} @chunks;
}
1;
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