#! /bin/sh

# Copyright (C) 1998 Stephane Levant <sun@tuxfamily.org>

#  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, 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; see the file COPYING.  If not, write to the
#  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
#  Boston, MA 02111-1307, USA.

version=1.0

prog=`basename $0`

version () {
cat << EOF
$prog $VERSION
EOF
exit
}

usage() {
cat << EOF >&2
Usage: $prog [OPTIONS] [FILE]...
       Display percentage usage of each character in FILE
       if FILE is omited, use STDIN.
       Options:
         -r REGEXP : use only characters witch match regexp
         -s : sort
	 -a : use only alphabetics characters (equivalent to -r '[a-z]')
	 -c : respect the case. the default is to assume upper-case
	      and lower-case characters are the same
EOF
exit 0
}

# Display an error message
error() {
echo "$prog: $1" >&2
exit 1
}

[ "$1" == "--help" ] && usage
[ "$1" == "--version" ] && version

sort=+1
case=1
reg=.
while getopts ":hvsacr:" i; do
  case "$i" in
    h*) usage ;;
    v*) version ;;
    a) reg=[a-z] ;;
    s) sort=-n ;;
    r) reg= "$OPTARG" ;;
    c) case=0 ;;
    *) error "Invalid option: $OPTARG. Try $prog -h" ;;
  esac
done

continue=yes
while [ $continue = yes -a $# -gt 0 ] ; do
  case $1 in
    --) shift; continue=no ;;
    -*) shift;;
    *) continue=no ;;
  esac
done

gawk -v case=$case -v reg="$reg" '
{ if (case)
    $0=tolower($0);
  for(i=1;i<=length($0);i++) {
    char=substr($0,i,1)
    if (char ~ reg) {
      t[char]++
      tot++
    }
  }
}
END {
  for (i in t)
    printf("%2.2f %s\n",t[i]/tot*100,i);
  }
' "$@" | sort $sort