#!/usr/bin/perl
##         universal cyrillic decoder
##---------------------------------------------------------------------------##
##  Copyright (C) 1995: Ilya Sandler isandler@utkux.utcc.utk.edu
##  This program is free software; you can redistribute it and/or modify
##  it under the terms of the GNU General Public License.
##  THERE IS NO WARRANTY OF ANY KIND. USE IT AT YOUR OWN RISK.
##---------------------------------------------------------------------------##
##  cyrcode   is a Perl program to convert between different
## cyrillic encodings, cyrcode uses external encoding table cyrtab.
## The program reads standard input and writes to standard output
## usage: 
## cyrcode.pl from to
## where from and to are names of encoding tables
## note table names should coincide with those indicated in cyrtab
##--------------------------------------------------------

open(dat,'/mit/kolya/arch/share/lib/cyrtab');
@names=&readnext;

if (($ARGV[0] eq "-help") || ($#ARGV < 1)){
    print "Universal cyrillic decoder \n";
    print "usage: \n  cyrcode.pl from to <infile >outfile";
    print "\n where 'from' and 'to' are the names of encoding tables \n";
    print "currently supported tables are: ", join(", ",@names), "\n" ;
    print "Example:    cyrcode.pl koi8 alt < file1.txt \n" ;
    print "converts file.txt from 'koi8' to 'alt' and writes the result to ";
    print "standard output \n";
    exit;
}  

#ignore cases
$ARGV[0] =~ y/A-Z/a-z/;
$ARGV[1] =~ y/A-Z/a-z/;
$from=$to=-1;

for ($i=0; $i <= $#names; $i++) {
    $names[$i]=~ y/A-Z/a-z/;
    if (index($ARGV[0],$names[$i]) >=0) {$from=$i;}
    if (index($ARGV[1], $names[$i]) >=0) {$to=$i;};
}

if (($from == -1) || ($to == -1)) {
    print "unknown encoding table name \n";
    print "known table names:",join(', ',@names),"\n";
    exit;
}

#initialize decoding table
for ($i = 0; $i < 256; $i++) {$decode[$i]=pack("c",$i)};
while (!eof(dat)){
    @m=&readnext;
    if ($m[0] eq "") {last;}
    if ($m[$from]=~ tr/a-z//){
	print "can not convert from ", $names[$from],"\n";
	exit;
    }
    if ($m[$to]=~tr/a-zA-Z\'\"//){$decode[$m[$from]]=$m[$to];}
    else{ $decode[$m[$from]]=pack("c",$m[$to]);}
#    print  $m[$to],'  ',$m[$from],"\n";
};



#actual convertion is here
while (!eof(STDIN)){
   print $decode[ord(getc)];
};

exit 0;

# subprograms----------------------
sub readnext {
    local($str)='';
    while ((!eof(dat))&&($str eq '')){ 
	$str=<dat>;
	$str=~ s/\n//g;   #strips \n
	$str=~ s/^[\ \t]+//g;   #strips leading white space
	$str=~ s/#[\0-\377]+//g;  #strips comment
   }
    split(/[\ \t]+/,$str);
}