#! /bin/ksh
# findbb -- write PostScript BoundingBox to stdout

# Notes:

# 0. The '-b' flag can be used with .pdf files.

# 1. (e)ps files may contain binary preview images and may
#    use non-native newlines, so must be handled as binary.  
#    Our approach is to grab the first 5000 bytes
#    of the file, then convert \012 and \015 to \012 for
#    processing with tools intended for use with text files.

# 2. if the file does not provide a BoundingBox line, use
#    the GhostScript bbox device (-b flag) to generate one.

# 3. if the first entry is %%BoundingBox: (atend), examine
#    the last 5000 bytes of the file

# Bugs:
#    Does not normalize the line by adding a space after the ':'
#    Does not handle large preview images

# Author: George N. White III <aa056@chebucto.ns.ca>
#     

pgm="$(basename $0)"
usage="usage: $pgm [-b] filename"

TMPDIR=${TMPDIR:-/usr/tmp}
GS_PROG=${GS_PROG:-gsc} 

tempnm=$(mktemp $TMPDIR/$pgm-temp.XXXXXXXXXX ) || exit 1
pipenm=$(mktemp $TMPDIR/$pgm-pipe.XXXXXXXXXX ) || exit 1
/sbin/rm -f "$pipenm" && /sbin/mknod "$pipenm" p

trap "rm -f $tempnm $pipenm ; exit \$rc" 0

flags=""
case $# in
2) case $1 in
   -b) flags="b$flags" ; shift
       ;;
    *) print -u2 $usage ; exit 1
       ;;
    esac
    ;;
1)  ;;
*)  print -u2 $usage ; exit 1
    ;;
esac

# can we read the file?
if [ -r "$1" ] ; then
    fnm="$1"
else
    print -u2 "$pgm: unable to read file <$1>."
    exit 1
fi

case $flags in
*b*) $GS_PROG -q -dBATCH -dNOPAUSE -sDEVICE=bbox $fnm > $tempnm 2>&1 
     set $(grep --max-count=1 '^%%BoundingBox:' $tempnm ) || exit 1
     ;;
*)   set $(head --bytes=5000 $fnm | tr '[\012\015]' '\012' | grep --max-count=1 '^%%BoundingBox:') || exit 1
     ;;
esac

case "$#" in
1|2) # handle '^%%BoundingBox:(atend)' and '^%%BoundingBox: (atend)'
   case "$1$2" in
   %%BoundingBox:\(atend\)) print -u2 "$pgm -- looking 'atend'"
       bbox=$(tail --bytes=5000 $fnm | tr '[\012\015]' '\012' \
            | grep '^%%BoundingBox:'|tail -1)
       ;;
   *)
       print -u2 "$pgm failed to find BoundingBox" ; exit 1
       ;;
   esac
   ;;
4|5) # handle BoundingBox:NN ... and BoundingBox: NN ...
   case "$1$2" in
   %%BoundingBox:*)   bbox="$@"
       ;;
   *)
       ;;
   esac
   ;;
*) print -u2 "$pgm failed to find BoundingBox, try setting '-b' flag." ; exit 1
   
esac
print "$bbox"