#! /usr/bin/gawk -f
# Last edited on 2013-11-20 22:48:48 by stolfilocal

BEGIN { maxlen = 6000000; FS = "\n"; }

function rejoin_lines(  nx) {
  # While $0 has a continuation mark, delete the mark and append
  # the next line:
  
  nx = $0;
  while ((nx != "") && (sub(/%$/, "", $0)) && (getline nx)) 
    { $0 = ( $0 nx );
      if (length($0) > maxlen) 
        { printf "line too long\n" > "/dev/stderr"; exit(1); }
    }
}

// {
  rejoin_lines();
  if ($0 ~ /[%]/) { 
    # Shoud write this in C...
    gsub(/%04/,"\004");
    gsub(/%07/,"\007");
    gsub(/%08/,"\010");
    gsub(/%09/,"\011");
    gsub(/%0A/,"\012");
    gsub(/%0C/,"\014");
    gsub(/%0D/,"\015");
    gsub(/%1B/,"\033");
    gsub(/%20/," ");
    gsub(/%26/,"\\&");  # !!!! GAWK BUG !!!!
    gsub(/%2B/,"\053");
    gsub(/%2E/,"\056");
    gsub(/%2F/,"/");
    gsub(/%3A/,":");
    gsub(/%3C/,"\074");
    gsub(/%3E/,"\076");
    gsub(/%7F/,"\177");
    gsub(/%A0/,"\240");
    gsub(/%A1/,"\241");
    gsub(/%A2/,"\242");
    gsub(/%A3/,"\243");
    gsub(/%A4/,"\244");
    gsub(/%A5/,"\245");
    gsub(/%A6/,"\246");
    gsub(/%A7/,"\247");
    gsub(/%A8/,"\250");
    gsub(/%A9/,"\251");
    gsub(/%AA/,"\252");
    gsub(/%AB/,"\253");
    gsub(/%AC/,"\254");
    gsub(/%AD/,"\255");
    gsub(/%AE/,"\256");
    gsub(/%AF/,"\257");
    gsub(/%B0/,"\260");
    gsub(/%B1/,"\261");
    gsub(/%B2/,"\262");
    gsub(/%B3/,"\263");
    gsub(/%B4/,"\264");
    gsub(/%B5/,"\265");
    gsub(/%B6/,"\266");
    gsub(/%B7/,"\267");
    gsub(/%B8/,"\270");
    gsub(/%B9/,"\271");
    gsub(/%BA/,"\272");
    gsub(/%BB/,"\273");
    gsub(/%BC/,"\274");
    gsub(/%BD/,"\275");
    gsub(/%BE/,"\276");
    gsub(/%BF/,"\277");
    gsub(/%C0/,"\300");
    gsub(/%C1/,"\301");
    gsub(/%C2/,"\302");
    gsub(/%C3/,"\303");
    gsub(/%C4/,"\304");
    gsub(/%C5/,"\305");
    gsub(/%C6/,"\306");
    gsub(/%C7/,"\307");
    gsub(/%C8/,"\310");
    gsub(/%C9/,"\311");
    gsub(/%CA/,"\312");
    gsub(/%CB/,"\313");
    gsub(/%CC/,"\314");
    gsub(/%CD/,"\315");
    gsub(/%CE/,"\316");
    gsub(/%CF/,"\317");
    gsub(/%D0/,"\320");
    gsub(/%D1/,"\321");
    gsub(/%D2/,"\322");
    gsub(/%D3/,"\323");
    gsub(/%D4/,"\324");
    gsub(/%D5/,"\325");
    gsub(/%D6/,"\326");
    gsub(/%D7/,"\327");
    gsub(/%D8/,"\330");
    gsub(/%D9/,"\331");
    gsub(/%DA/,"\332");
    gsub(/%DB/,"\333");
    gsub(/%DC/,"\334");
    gsub(/%DD/,"\335");
    gsub(/%DE/,"\336");
    gsub(/%DF/,"\337");
    gsub(/%E0/,"\340");
    gsub(/%E1/,"\341");
    gsub(/%E2/,"\342");
    gsub(/%E3/,"\343");
    gsub(/%E4/,"\344");
    gsub(/%E5/,"\345");
    gsub(/%E6/,"\346");
    gsub(/%E7/,"\347");
    gsub(/%E8/,"\350");
    gsub(/%E9/,"\351");
    gsub(/%EA/,"\352");
    gsub(/%EB/,"\353");
    gsub(/%EC/,"\354");
    gsub(/%ED/,"\355");
    gsub(/%EE/,"\356");
    gsub(/%EF/,"\357");
    gsub(/%F0/,"\360");
    gsub(/%F1/,"\361");
    gsub(/%F2/,"\362");
    gsub(/%F3/,"\363");
    gsub(/%F4/,"\364");
    gsub(/%F5/,"\365");
    gsub(/%F6/,"\366");
    gsub(/%F7/,"\367");
    gsub(/%F8/,"\370");
    gsub(/%F9/,"\371");
    gsub(/%FA/,"\372");
    gsub(/%FB/,"\373");
    gsub(/%FC/,"\374");
    gsub(/%FD/,"\375");
    gsub(/%FE/,"\376");
    gsub(/%FF/,"\377");
    gsub(/%3D/,"=");
  }
  print;
}