#!/usr/bin/env perl

## jpg-recover-faster -- Copyright (c) 2006-2007, Nathan Arthur (truist-jpgrecover@rainskit.com)
## Program heavily based on jpg-recover, by Adam Glass (clarity.net@adam)
## Original copyright: jpg-recover -- Copyright (c) 2001-2002, Adam Glass <clarity.net@adam>
##
## jpg-recover scans through a file (probably a disk image) looking for
##  JPEG headers, copying them to sequential filenames.
##
## NOTE!  USE THIS PROGRAM AT YOUR OWN RISK; THIS PROGRAM COMES WITH
##        NO WARRANTY WHATSOEVER.
##
## Permission to use, copy, modify, and distribute this software for any
## purpose with or without fee is hereby granted, provided that the above
## copyright notice and this permission notice appear in all copies.
##
## Generally, the following variables are fine -- you may want to tune
## them if you know what you're doing, but you shouldn't have to.
##
## $minsize may be worth fiddling with, since the end marker ('FFD9')
## is not unique -- it can occur multiple times within JPEG data.
## If $minsize is set too low, you'll end up with truncated images (false
## matches on the end marker), but if $minsize is too long, jpg-recover
## will miss the end of the file -- and combine two images or simply have
## corruption at the end of the image.  So you may need to try a number
## of different values.  (The units are bytes; the default is to not
## believe the data in the file if it's specifying an image shorter
## than 102400 bytes -- 100k.)
##
## ------------------------------------------------------------------------

if ($ARGV[0] ne "") {
  $infile=$ARGV[0];     # use user-defined file if one is supplied
} else {
  $infile="smcard.img"; # default input file to read (the disk image file)
}

### CONFIGURE THESE VARIABLES

$outtemp="lostpic{}.jpg"; # output file template: '{}' is replaced with file #
$filenum=1;             # output file numbering starts here

$position=0;            # position in input file, for restarting output
$minsize=262144;        # ignore apparent JPEG file end markers before here
$maxsize=10485760;		#   give up after here
$announce=102400;       # announce position every 100k (0=disable announcemnts)
$maxbufsize=$maxsize * 2;         # maximum buffer size (must be greater than $maxsize)
								  # adjust this if you are running out of memory

### END OF CONFIGURABLE SECTION ###


$state=0;               # current read state: 0=waiting for start marker,
                        #                     1=inside file, waiting for end
$outlen=0;              # output file length (for pretty output)

$buffer="";             # scanning buffer (leave this alone)
$freshread="";          # where characters get read in (leave this alone)

$intro = "\xff\xd8\xff";
$ignorelen = length("\xe1\x1c\x45");
@ending = ( "\x45\x78\x69\x66", "\x4a\x46\x49\x46" );
$markersize=60;
$end="\xff\xd9";        # JPEG end marker

$starttime = time() - 1;
select((select(STDOUT), $|=1)[0]);	#auto-flush stdout

open(INF,"< $infile") or die "couldn't open $infile";
binmode(INF);
print "Scanning '$infile' looking for pictures...\n";

if ($position > 0) {
	seek(INF, 229309480, 0);
}

$bufferpos=$maxbufsize;

while(!eof(INF)) {
	$position += read(INF, $freshread, $bufferpos);
	$buffer = substr($buffer, $bufferpos) . $freshread;

	$kbs = ($position / 1024) / (time() - $starttime);
   	print "Passing byte $position of $infile ... $kbs kb/s\n";
	
	$bufferpos = findfile();
}

print "Finished\n";
close INF;
exit 0;


sub findfile {
	local $start = findstart(0, $maxsize);

	if ($start > -1) {
		local $endpos = findend($start);
		if ($endpos > $start) {
			local $secondstart = findstart($start + 1, $endpos);
			if ($secondstart > -1) {
				return $secondstart;
			} else {
				writefile($start, $endpos + length($end), false);
				return $endpos;
			}
		} else {
			return $start + 1;
		}
	} else {
		return $maxsize;
	}
}

sub findstart()
{
	local ($start,$end) = @_;
	while (true) {
		$start = index($buffer, $intro, $start);
		if ($start > $end || $start < 0) {
			return -1;
		} else {
			local $subbuf = substr($buffer, $start + length($intro) + $ignorelen, length($ending[0]));
			if ($subbuf eq $ending[0] || $subbuf eq $ending[1]) {
				return $start;
			} else {
				$start = $start + 1;
			}
		}
	}
}

sub findend()
{
	local $start = @_;
	local $subbuf = substr($buffer, $start, $maxsize);
	return index($subbuf, $end, $minsize) + $start;
}

sub writefile()
{
	local ($start, $endpos, $addend) = @_;
	local $length = $endpos - $start;
	
	local $foundpos = $position + $start;
	print "Found file #$filenum at position $foundpos with $length bytes\n";
	$outfile = seq_filename($outtemp, $filenum);
	open(OUTF, ">$outfile");
	binmode(OUTF);

	local $contents = substr($buffer, $start, $length);
	if ($addend) {
		$contents = $contents . $end;
	}
	print OUTF $contents;
	close OUTF;

	$filenum += 1;
}

sub seq_filename {
	local ($template,$number) = @_;
	local $numstr = sprintf("%.4d",$number);
	$template =~ s/{}/$numstr/;
	return $template;
}