#!/bin/bash
#  
# This file is a part of PFS CALIBRATION package.
# ---------------------------------------------------------------------- 
# Copyright (C) 2004 Grzegorz Krawczyk, <gkrawczyk@users.sourceforge.net>
# 
#  This program is free software; you can redistribute it and/or modify
#  it under the terms of the GNU General Public License as published by
#  the Free Software Foundation; either version 2 of the License, or
#  (at your option) any later version.
#
#  This program is distributed in the hope that it will be useful,
#  but WITHOUT ANY WARRANTY; without even the implied warranty of
#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#  GNU General Public License for more details.
#
#  You should have received a copy of the GNU General Public License
#  along with this program; if not, write to the Free Software
#  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
# ---------------------------------------------------------------------- 
#
# $Id: jpeg2hdrgen,v 1.6 2006/08/22 18:34:04 gkrawczyk Exp $

LC_NUMERIC=POSIX         # ensure dot is used as the decimal separator
export LC_NUMERIC

LC_ALL=POSIX             # apparently this is necessary on Gentoo
export LC_ALL


JHEAD='jhead'                   # program for extracting exif info from jpegs
EXIF='exif'                     # another one
EXIV2='exiv2'                   # and one more

CMD=`which ${JHEAD}`
[ -n "${CMD}" ] || CMD=`which ${EXIF}`
[ -n "${CMD}" ] || CMD=`which ${EXIV2}`
if [ -z "${CMD}" ]
then
    cat <<MSG
One of the following commands are required to run this script:
 '${JHEAD}' - stand-alone program (http://www.sentex.net/~mwandel/jhead/)
 '${EXIF}'  - part of libexif project (http://sf.net/projects/libexif/)
 '${EXIV2}' - part of exiv2 project (http://www.exiv2.org/)
MSG
    exit 1;
fi

AWK_PROGRAM='
BEGIN {
  exposure="";
  aperture="";
}

END {
  if( aperture=="" )
    aperture=1;

  if( iso_speed=="" )
    iso_speed=100;
    
  if( exposure=="" )
    printf("not recognized exif header!\n");
  else
    print exposure " " aperture " " iso_speed " 0";
}

## jhead output
/^Exposure time: ([0-9]*\.[0-9]) */ {
  exposure = 1/$3;
}
/^Aperture *: f\/([0-9]*\.[0-9]*)/ {
  aperture = substr($3,3);
}
/^ISO equiv. *: ([0-9]*\.?[0-9]*)/ {
  iso_speed = $4;
}

## exif output
/^Exposure Time *\|.+ sec\./ {
  if (split(substr($3,2),a,"/") == 2)
    exposure = a[2];
  else
    exposure = 1/a[1];
}
/^FNumber *\|f\/.+/ {
    aperture = substr($2,4);
}
/^ISO Speed Ratings *\|.+/ {
    iso_speed = substr($4,2);
}

## exiv2 output
/^Exposure time *: .+ s/ {
  if (split($4,a,"/") == 2)
    exposure = a[2];
  else
    exposure = 1/a[1];
}
/^Aperture *: F.+/ {
    aperture = substr($3,2);
}
/^ISO speed *: .+/ {
    iso_speed = $4;
}
'

while [ ${#} -ne 0 ]
do
    printf "${1} "
    ${CMD} "${1}" | awk "${AWK_PROGRAM}"
    shift
done