#!perl -w
# (C) 2003-2007 Willem Jan Hengeveld <itsme@xs4all.nl>
# Web: http://www.xs4all.nl/~itsme/
#      http://wiki.xda-developers.com/
#
# $Id$
#
use strict;
$|=1;
use IO::File;
use Getopt::Long;

for my $fn (@ARGV) {
    print "--$fn\n" if (@ARGV>1);
    processfile($fn);
}
sub processfile {
    my ($fn)=@_;
    my $fh= IO::File->new($fn, "r") or die "$fn: $!";
    binmode $fh;

    my $data;
    $fh->read($data, -s $fh);
    if ($data =~ /^BM/) {
        BMP::decode($data, 0);
    }
    elsif ($data =~ /^GIF/) {
        GIF::decode($data, 0);
    }
   elsif ($data =~ /^\xff\xd8/) {
       JPG::decode($data, 0);
   }
   elsif ($data =~ /^\x89PNG\x0d\x0a\x1a\x0a/s) {
       PNG::decode($data, 0);
   }
    elsif ($data =~ /^\x00\x00\x01\x00.\x00...\x00.\x00.\x00/) {
        ICO::decode($data, 0);
    }
    elsif ($data =~ /^\x00\x00\x02\x00.\x00...\x00.\x00.\x00/) {
        CUR::decode($data, 0);
    }
    else {
        printf("unknown image: hdr: %s\n", unpack("H32", $data));
    }
}
sub decodestruct {
    my $ofs= $_[1];
    my %struct;
    my @struct_fields= @{$_[4]};
    my @struct_format= @{$_[5]};

    if (0) {    # for debugging formats
    die sprintf("fields=%d  fmt=%d  %s\n", scalar @struct_fields, scalar @struct_format, join(",", @struct_fields))
        if (@struct_fields != @struct_format);
    die sprintf("fmt size=%d len=%d: %s\n", length(pack($_[3], 0..100)), $_[2], $_[3])
        if (length(pack($_[3], 0..100)) != $_[2]);
    die sprintf("fmt fields=%d str=%d: %s\n", scalar unpack($_[3], "\x00" x $_[2]), scalar @struct_fields, $_[3])
        if (scalar @{[unpack($_[3], "\x00" x $_[2])]} != @struct_fields);
    }

    my @struct_values= unpack($_[3], substr($_[0], $ofs, $_[2]));
    $struct{$struct_fields[$_]}=$struct_values[$_] for (0..$#struct_fields);
    printf("%-20s: $struct_format[$_]\n", $struct_fields[$_], $struct_values[$_]) for (0..$#struct_fields);

    return \%struct;
}
###################################################################################
package BMPInfo;

sub decode {
    return main::decodestruct($_[0], $_[1], 40, "VVVvvVVVVVV", 
        [qw(biSize biWidth biHeight biPlanes biBitCount biCompression biSizeImage biXPelsPerMeter biYPelsPerMeter biClrUsed biClrImportant)], 
        [qw(0x%08x %5d %5d 0x%04x 0x%04x 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x 0x%08x)]);
}

package BMPHdr;

sub decode {
    return main::decodestruct($_[0], $_[1], 14, "vVvvV",
        [qw(bfType bfSize bfReserved1 bfReserved2 bfOffBits)],
        [qw(0x%04x 0x%08x 0x%04x 0x%04x 0x%08x)]);
}

package BMP;

sub decode {
    my $ofs= $_[1];

    my $hdr= BMPHdr::decode($_[0], $ofs);
    my $info= BMPInfo::decode($_[0], $ofs+14);

    return { hdr=>$hdr, info=>$info };
}
###################################################################################
package ICOHdr;
sub decode {
    return main::decodestruct($_[0], $_[1], 6, "vvv",
        [qw(idReserved idType idCount)],
        [qw(0x%04x 0x%04x 0x%04x)]);

}
package ICOEntry;
sub decode {
    return main::decodestruct($_[0], $_[1], 16, "CCCCvvVV",
        [qw(bWidth bHeight bColorCount bReserved wPlanes wBitCount dwBytesInRes dwImageOffset)],
        [qw(%5d %5d 0x%02x 0x%02x 0x%04x 0x%04x 0x%08x 0x%08x)]);

}

package ICO;
sub decode {
    my $hdr= ICOHdr::decode($_[0], $_[1]);
    my @entries= map { ICOEntry::decode($_[0], 6+16*$_) } (0..$hdr->{idCount}-1);
    my @icons= map { BMPInfo::decode($_[0], $entries[$_]{dwImageOffset}) } (0..$hdr->{idCount}-1);

    return { hdr=>$hdr, entries=>\@entries, icons=>\@icons };
}
package CUR;
sub decode {
    my $hdr= ICOHdr::decode($_[0], $_[1]);
    my @entries= map { ICOEntry::decode($_[0], 6+16*$_) } (0..$hdr->{idCount}-1);
    my @icons= map { BMPInfo::decode($_[0], $entries[$_]{dwImageOffset}) } (0..$hdr->{idCount}-1);

    return { hdr=>$hdr, entries=>\@entries, icons=>\@icons };
}


###################################################################################
package GIFHdr;
sub decode {
    my $hdr= main::decodestruct($_[0], $_[1], 13, "a3a3vvCCC",
        [qw(signature version width height packed backgroundColor aspectRatio)],
        [qw(%s %s %5d %5d 0x%02x 0x%02x 0x%02x)]);

    $hdr->{colortableEntrySize}= $hdr->{packed}&0x7;
    $hdr->{colortableSortFlag}= ($hdr->{packed}&0x8)>>3;
    $hdr->{colortableResolution}= ($hdr->{packed}&0x70)>>4;
    $hdr->{colortableFlag}= ($hdr->{packed}&0x80)>>7;

    return $hdr;
}
package GIF;

sub decode {
    my $hdr= GIFHdr::decode($_[0], $_[1]);

    return { hdr=>$hdr };
}
package JPG;
our %markers;
sub INIT {
    $markers{0xffe0}= { name=>'APP0', decoder=>sub {
            my ($magic, $version, $units, $xdensity, $ydensity, $xthumb, $ythumb, $rgb)= unpack("A5nCnnCCa*", $_[0]);
            printf("%-5s v0x%04x %s, density:(%d,%d) thumb:(%d,%d), rgb:%s\n",
                $magic, $version, $units==0?"pixel":$units==1?"inch":$units==2?"cm":$units,
                $xdensity, $ydensity, $xthumb, $ythumb, unpack("H*", $rgb));
        } };
    $markers{0xffc0}= { name=>'SOF0', decoder=>sub {
            my ($depth, $height, $width)= unpack("Cnn", $_[0]);
            printf("depth: %d\n", $depth);
            printf("width: %d\n", $width);
            printf("height: %d\n", $height);
        } };
};
sub decode {
    my $ofs= $_[1];
    $ofs+=2;  # skip 0xffd8
    my @chunks;
    while ($ofs<length($_[0])) {
        my ($type, $size)= unpack("nn", substr($_[0], $ofs, 4));
        my $content= substr($_[0], $ofs+4, $size-2);
        if (exists $markers{$type}) {
            $markers{$type}{decoder}->($content);
        }
        last if $type==0xffda;
        $ofs += $size+2;
    }
}
package PNG;
sub decode {
    my $ofs= $_[1]+8;
    while ($ofs<length($_[0])) {
        # format:
        #    uint32_t  size
        #    uint32_t  tag
        #    uint8_t   data[size]
        #    uint32_t  crc;       // crc of tag + data
        my ($size, $tag)= unpack("Na4", substr($_[0], $ofs, 8));
        my $content= substr($_[0], $ofs+8, $size);
        my $crc= unpack("N", substr($_[0], $ofs+8+$size));
        # crc = crc32($tag.$content)
        if ($tag eq "IHDR") {
            my ($width, $height, $depth)= unpack("NNC", $content);
            printf("depth: %d\n", $depth);
            printf("width: %d\n", $width);
            printf("height: %d\n", $height);
        }
        else {
            #printf("tag %s size=%d\n", $tag, $size);
        }
        $ofs += 12+$size;
    }
    printf("ofs=0x%x, l=0x%x\n", $ofs, length($_[0]));
}