#!/usr/bin/perl
#
# camtoppm $Revision: 1.0 $ programmed by SENDA Shuji
#
# Convert cam-file to ppm (or jpeg) file
#

require 'getopts.pl';
&Getopts("hctjp");

if ($opt_h || $#ARGV > 0) {
    print STDERR "Usage : $0 [-c|-t|-j|-p] [cam_file]\n";
    print STDERR "-c : print comments\n";
    print STDERR "-t : output thumbnail image 52x36 (ppm)\n";
    print STDERR "-j : output full image 480x240 (jpeg)\n";
    print STDERR "-p : output full image 480x240 (ppm) [default]\n";
    exit 0;
}

$area_comment = 1;
$area_thumbnail = 2;
$area_jfif = 3;

&setconst;			# set JFIF constant tables

if ($opt_c) {
    $pickid = $area_comment;
} elsif ($opt_t) {
    $pickid = $area_thumbnail;
} else {
    $pickid = $area_jfif;
}

if ($#ARGV) {
    open(FILE, "-");
    $ARGV[0] = "stdin";
} else {
    open(FILE, $ARGV[0]) || die "$ARGV[0] can not be opened";
}
$narea = &camopen(FILE) || die "$ARGV[0] is not cam file";
$off = 0;
foreach (1..$narea) {
    ($id, $len) = &camarea(FILE);
    if ($id == $pickid) {
	$pickoff = $off;
    }
    $off += $len;
}
die "can not find ID:$pickid" if (!defined($pickoff));
if ($pickoff) {
    read(FILE, $buf, $pickoff) || die "read error"; # dummy read
}

if ($pickid == $area_comment) {
    while (1) {
	read(FILE, $cid, 1);
	last if ($cid eq "\x00");
	$cid = unpack("C", $cid);
	$comment = "";
	while (1) {
	    read(FILE, $buf, 1);
	    last if ($buf eq "\x00");
	    $comment .= $buf;
	}
	print "($cid)$comment\n";
    }
} elsif ($pickid == $area_thumbnail) {
    read(FILE, $data, $len);
    print "P6\n52 36\n255\n$data";
} elsif ($pickid == $area_jfif) {
    if (!$opt_j || $opt_p) {
	open(PPMOUT, "|djpeg");
	select(PPMOUT);
    }

    read(FILE, $buf, 8) || die "read error";
    ($narea, $ysize, $usize, $vsize) = unpack("nnnn", $buf);
    die "JFIF area number != 3" if ($narea != 3);

    print "$soi";
    print "$app0";
    print "$dqt0";
    read(FILE, $buf, 64);
    print "$buf";
    print "$dqt1";
    read(FILE, $buf, 64);
    print "$buf";
    print "$sof";
    print "$dht";

    print "$sos_y";
    read(FILE, $buf, $ysize);
    print "$buf";
    print "$sos_u";
    read(FILE, $buf, $usize);
    print "$buf";
    print "$sos_v";
    read(FILE, $buf, $vsize);
    print "$buf";

    print "$eoi";
}
exit 0;

sub camopen {			# return (narea)
    local($fd) = @_;
    local($buf);

    read($fd, $buf, 4) || die "read error";
    return undef if ($buf ne "\x07\x20\x4d\x4d");
    read($fd, $buf, 2) || die "read error";
    return unpack("n", $buf);
}

sub camarea {			# return (ID, length)
    local($fd) = @_;
    local($buf);

    read($fd, $buf, 16) || die "read error";
    return unpack("nN", $buf);
}

sub setconst {
    $soi = pack("H*", "ffd8");
    $app0 = pack("H*", "ffe000104a46494600010101012c012c0000");
    $dqt0 = pack("H*", "ffdb004300");
    $dqt1 = pack("H*", "ffdb004301");
    $sof = pack("H*", "ffc000110800f001e003013200021101031101");
    $dht = pack("H*", "ffc4001f00" .
		"00010501010101010100000000000000" .
		"000102030405060708090a0b" .
		"ffc400b510" .
		"0002010303020403050504040000017d" .
		"01020300041105122131410613516107" .
		"227114328191a1082342b1c11552d1f0" .
		"2433627282090a161718191a25262728" .
		"292a3435363738393a43444546474849" .
		"4a535455565758595a63646566676869" .
		"6a737475767778797a83848586878889" .
		"8a92939495969798999aa2a3a4a5a6a7" .
		"a8a9aab2b3b4b5b6b7b8b9bac2c3c4c5" .
		"c6c7c8c9cad2d3d4d5d6d7d8d9dae1e2" .
		"e3e4e5e6e7e8e9eaf1f2f3f4f5f6f7f8" .
		"f9fa" .
		"ffc4001f01" .
		"00030101010101010101010000000000" .
		"000102030405060708090a0b" .
		"ffc400b511" .
		"00020102040403040705040400010277" .
		"00010203110405213106124151076171" .
		"1322328108144291a1b1c109233352f0" .
		"156272d10a162434e125f11718191a26" .
		"2728292a35363738393a434445464748" .
		"494a535455565758595a636465666768" .
		"696a737475767778797a828384858687" .
		"88898a92939495969798999aa2a3a4a5" .
		"a6a7a8a9aab2b3b4b5b6b7b8b9bac2c3" .
		"c4c5c6c7c8c9cad2d3d4d5d6d7d8d9da" .
		"e2e3e4e5e6e7e8e9eaf2f3f4f5f6f7f8" .
		"f9fa");
    $sos_y = pack("H*", "ffda0008010100003f00");
    $sos_u = pack("H*", "ffda0008010211003f00");
    $sos_v = pack("H*", "ffda0008010311003f00");
    $eoi = pack("H*", "ffd9");
}