Before showing you the code, some notes.

• You are mixing text (the boundary delimiters) and binary data. This is bad
• You are writing out hexadecimal representations of numbers, but you want to save space. This makes little sense
• You should really use pack

Now, I changed the encoding. Now it is:

• one long, for the index length
• the index. Each entry in the index is made of:
  1. one long: the index number
  2. one long: the string length
  3. some bytes: the string itself
• the content, as a series of longs

And now, the code:

Encoder:

#!/usr/bin/perl

@lines = <>;

binmode STDOUT;
$x = 1;
foreach $ln (@lines) {
  @words = split /\s+/, $ln;
  foreach $word (@words) {
    $index{$word} = $x++;
    $count{$word}++;
  }
}

$idx='';
foreach $key (keys %index) {
  $idx.=pack("N(N/a*)",$index{$key},$key);
}

print STDOUT pack("N",length($idx)),$idx;

foreach $ln (@lines) {
  @words = split /\s+/, $ln;
  foreach $word (@words) {
    print STDOUT pack("N",$index{$word});
  }
}
[download]

Decoder:

#!/usr/bin/perl
binmode STDIN;
undef $/;
$i=<>;
$is=unpack "N",$i;
$ind=substr($i,4,$is);$con=substr($i,4+$is);
%index=unpack "(N(N/a))*",$ind;
@con=unpack "N*",$con;
print join(' ',@index{@con});
[download]

Note the use of binmode and the unsetting of $/ (aka input record separator).

-- 
        dakkar - Mobilis in mobile

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In reply to Re: help needed on encoding a text file by dakkar
in thread help needed on encoding a text file by bfdi533

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