Just in time processing on a character stream

Just in time processing on a character stream is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

Given a stream of characters, presumably (simulated) from a keyboard, that contain the separators "formfeed", "linefeed", "tab" and "space" characters. Print out the i^th character of the i^th tab-field of the i^th line of the i^th page to reveal a secret password.

Stop processing immediately upon encountering a "!" found uniquely in this i,i,i,i position (least the system self destruct). The "!" may be found/permitted else where however, in which case it should be ignored.

Ideally this can be generalise as follows:

• The separators (formfeed, linefeed, tab, space) provided from a user supplied array and can include additional/alternative separators, e.g. (formfeed, linefeed, ".", "," ," ",...).
• These selection criterial is generalised i^th,i^th,i^th,i^th to a boolean function of f(page,line,field,word,...) or f(i^th,j^th,k^th,l^th,m^th,etc...)

Provide a reasonably interesting message to be decoded, e.g. Silence-Dogood. Your choice.

This task was inspired by the movie "National Treasure" with refers to a "book cipher".

C

Translation of: C++

<lang c>#include <stdbool.h>

1. include <stdio.h>
2. include <stdlib.h>

struct UserInput {

   char formFeed;
   char lineFeed;
   char tab;
   char space;

};

struct UserInputNode {

   struct UserInput ui;
   struct UserInputNode *next;

};

bool decode(FILE *fp, const struct UserInput ui) {

   char f = 0, l = 0, t = 0, s = 0;
   char buffer[1];

   while (fread(buffer, 1, 1, fp)) {
       char c = buffer[0];

       if (f == ui.formFeed && l == ui.lineFeed && t == ui.tab && s == ui.space) {
           if (c == '!')
               return false;
           putchar(c);
           return true;
       } else if (c == '\f') {
           f++;
           l = t = s = 0;
       } else if (c == '\n') {
           l++;
           t = s = 0;
       } else if (c == '\t') {
           t++;
           s = 0;
       } else {
           s++;
       }
   }

   return false;

}

void decodeFile(char *fileName, struct UserInputNode *uin) {

   FILE *fp;

   fp = fopen(fileName, "r");
   if (NULL == fp) {
       fprintf(stderr, "Could not find %s\n", fileName);
       return;
   }

   if (NULL == uin) {
       fprintf(stderr, "No user input detected!\n");
       return;
   }

   while (NULL != uin) {
       if (!decode(fp, uin->ui)) {
           break;
       }
       fseek(fp, 0, SEEK_SET);
       uin = uin->next;
   }
   printf("\n\n");

}

struct UserInputNode *getUserInput() {

   struct UserInputNode *uip, *temp;

   // 0 18 0 0
   temp = malloc(sizeof(struct UserInputNode));
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 18;
   temp->ui.tab = 0;
   temp->ui.space = 0;
   uip = temp;

   // 0 68 0 1
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 68;
   temp->ui.tab = 0;
   temp->ui.space = 1;

   // 0 100 0 32
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 100;
   temp->ui.tab = 0;
   temp->ui.space = 32;

   // 0 114 0 45
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 114;
   temp->ui.tab = 0;
   temp->ui.space = 45;

   // 0 38 0 26
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 38;
   temp->ui.tab = 0;
   temp->ui.space = 26;

   // 0 16 0 21
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 16;
   temp->ui.tab = 0;
   temp->ui.space = 21;

   // 0 17 0 59
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 17;
   temp->ui.tab = 0;
   temp->ui.space = 59;

   // 0 11 0 29
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 11;
   temp->ui.tab = 0;
   temp->ui.space = 29;

   // 0 102 0 0
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 102;
   temp->ui.tab = 0;
   temp->ui.space = 0;

   // 0 10 0 50
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 10;
   temp->ui.tab = 0;
   temp->ui.space = 50;

   // 0 39 0 42
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 39;
   temp->ui.tab = 0;
   temp->ui.space = 42;

   // 0 33 0 50
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 33;
   temp->ui.tab = 0;
   temp->ui.space = 50;

   // 0 46 0 54
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 46;
   temp->ui.tab = 0;
   temp->ui.space = 54;

   // 0 76 0 47
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 76;
   temp->ui.tab = 0;
   temp->ui.space = 47;

   // 0 84 2 28
   temp->next = malloc(sizeof(struct UserInputNode));
   temp = temp->next;
   temp->ui.formFeed = 0;
   temp->ui.lineFeed = 84;
   temp->ui.tab = 2;
   temp->ui.space = 28;

   temp->next = NULL;
   return uip;

}

void freeUserInput(struct UserInputNode *uip) {

   if (NULL == uip) {
       return;
   }

   freeUserInput(uip->next);
   uip->next = NULL;

   free(uip);

}

int main() {

   struct UserInputNode *uip;

   uip = getUserInput();
   decodeFile("theRaven.txt", uip);
   freeUserInput(uip);

   return 0;

}</lang>

Output:

Silence-Dogood.

C#

Translation of: D

<lang csharp>using System; using System.Collections.Generic; using System.Linq;

namespace JustInTimeProcessing {

   struct UserInput {
       public UserInput(string ff, string lf, string tb, string sp) {
           FormFeed = (char)int.Parse(ff);
           LineFeed = (char)int.Parse(lf);
           Tab = (char)int.Parse(tb);
           Space = (char)int.Parse(sp);
       }

       public char FormFeed { get; }
       public char LineFeed { get; }
       public char Tab { get; }
       public char Space { get; }
   }

   class Program {
       static List<UserInput> GetUserInput() {
           string h = "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 "
               + "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28";
           return h.Split(' ')
               .Select((x, idx) => new { x, idx })
               .GroupBy(x => x.idx / 4)
               //.Select(g => g.Select(a => a.x))
               .Select(g => {
                   var ge = g.Select(a => a.x).ToArray();
                   return new UserInput(ge[0], ge[1], ge[2], ge[3]);
               })
               .ToList();
       }

       static void Decode(string filename, List<UserInput> uiList) {
           string text = System.IO.File.ReadAllText(filename);

           bool Decode2(UserInput ui) {
               char f = (char)0;
               char l = (char)0;
               char t = (char)0;
               char s = (char)0;

               foreach (char c in text) {
                   if (f == ui.FormFeed && l == ui.LineFeed && t == ui.Tab && s == ui.Space) {
                       if (c == '!') return false;
                       Console.Write(c);
                       return true;
                   }
                   if (c == '\u000c') {
                       f++; l = (char)0; t = (char)0; s = (char)0;
                   } else if (c == '\n') {
                       l++; t = (char)0; s = (char)0;
                   } else if (c == '\t') {
                       t++; s = (char)0;
                   } else {
                       s++;
                   }
               }

               return false;
           }

           foreach (UserInput ui in uiList) {
               if (!Decode2(ui)) {
                   break;
               }
           }
           Console.WriteLine();
       }

       static void Main(string[] args) {
           var uiList = GetUserInput();
           Decode("theraven.txt", uiList);

           Console.ReadLine();
       }
   }

}</lang>

Output:

Silence-Dogood.

C++

Text used to encode:The Raven - by E.A.Poe <lang cpp>

1. include <vector>
2. include <iostream>
3. include <fstream>
4. include <sstream>

typedef struct {

   int s[4];

}userI;

class jit{ public:

   void decode( std::string& file, std::vector<userI>& ui ) {
       std::ifstream f( file.c_str(), std::ios_base::in );
       fileBuffer = std::string( ( std::istreambuf_iterator<char>( f ) ), std::istreambuf_iterator<char>() );
       f.close();
       for( std::vector<userI>::iterator t = ui.begin(); t != ui.end(); t++ ) {
           if( !decode( ( *t ).s ) ) break;
       }
       std::cout << "\n\n";
   }

private:

   bool decode( int* ui ) {
       int l = 0, t = 0, p = 0, c = 0, a = 0;
       for( std::string::iterator i = fileBuffer.begin(); i != fileBuffer.end(); i++ ) {
           if( p == ui[0] && l == ui[1] && t == ui[2] && c == ui[3] ) {
               if( *i == '!' )  return false;
               std::cout << *i; return true;
           }
           if( *i == '\n' )      { l++; t = c = 0; }  
           else if( *i == '\t' ) { t++; c = 0; }
           else if( *i == '\f' ) { p++; l = t = c = 0; }
           else                  { c++;}
       }
       return false;
   }
   std::string fileBuffer;

}; void getUserInput( std::vector<userI>& u ) {

   std::string h = "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 "
                   "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28";
   //std::getline( std::cin, h );
   std::stringstream ss( h );
   userI a;
   int x = 0;
   while( std::getline( ss, h, ' ' ) ) {
       a.s[x] = atoi( h.c_str() );
       if( ++x == 4 ) {
           u.push_back( a );
           x = 0;
       }
   }

} int main( int argc, char* argv[] ) {

   std::vector<userI> ui;
   getUserInput( ui );

   jit j;
   j.decode( std::string( "theRaven.txt" ), ui );
   return 0;

} </lang>

Output:

Silence-Dogood.

D

Translation of: Kotlin

<lang D>import std.algorithm; import std.array; import std.conv; import std.file; import std.range; import std.stdio;

struct UserInput {

   char formFeed;
   char lineFeed;
   char tab;
   char space;

   this(string ff, string lf, string tb, string sp) {
       formFeed = cast(char) ff.to!int;
       lineFeed = cast(char) lf.to!int;
       tab = cast(char) tb.to!int;
       space = cast(char) sp.to!int;
   }

}

auto getUserInput() {

   auto h = "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 "
          ~ "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28";
   auto ctor = (string[] a) => UserInput(a[0], a[1], a[2], a[3]);
   return h.split(' ').chunks(4).map!ctor.array;

}

void decode(string fileName, UserInput[] uiList) {

   auto text = readText(fileName);

   bool decode2(UserInput ui) {
       char f = 0;
       char l = 0;
       char t = 0;
       char s = 0;
       foreach (c; text) {
           if (f == ui.formFeed && l == ui.lineFeed && t == ui.tab && s == ui.space) {
               if (c == '!') return false;
               write(c);
               return true;
           }
           if (c == '\u000c') {
               f++; l=0; t=0; s=0;
           } else if (c == '\n') {
               l++; t=0; s=0;
           } else if (c == '\t') {
               t++; s=0;
           } else {
               s++;
           }
       }
       return false;
   }

   foreach (ui; uiList) {
       if (!decode2(ui)) break;
   }
   writeln;

}

void main() {

   auto uiList = getUserInput();
   decode("theRaven.txt", uiList);

}</lang>

Output:

Silence-Dogood.

Go

Translation of: C++

<lang go>package main

import (

   "fmt"
   "io/ioutil"
   "log"
   "strconv"
   "strings"

)

type userInput struct{ formFeed, lineFeed, tab, space int }

func getUserInput() []userInput {

   h := "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 " +
       "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28"
   flds := strings.Fields(h)
   var uis []userInput
   var uif [4]int
   for i := 0; i < len(flds); i += 4 {
       for j := 0; j < 4; j++ {
           uif[j], _ = strconv.Atoi(flds[i+j])
       }
       uis = append(uis, userInput{uif[0], uif[1], uif[2], uif[3]})
   }
   return uis

}

func decode(fileName string, uis []userInput) error {

   text, err := ioutil.ReadFile(fileName)
   if err != nil {
       return err
   }

   decode2 := func(ui userInput) bool {
       var f, l, t, s int
       for _, c := range text {
           if f == ui.formFeed && l == ui.lineFeed && t == ui.tab && s == ui.space {
               if c == '!' {
                   return false
               }
               fmt.Printf("%c", c)
               return true
           }
           switch c {
           case '\f':
               f++
               l = 0
               t = 0
               s = 0
           case '\n':
               l++
               t = 0
               s = 0
           case '\t':
               t++
               s = 0
           default:
               s++
           }
       }
       return true
   }

   for _, ui := range uis {
       if !decode2(ui) {
           break
       }
   }
   fmt.Println()
   return nil

}

func main() {

   uis := getUserInput()
   err := decode("theRaven.txt", uis)
   if err != nil {
       log.Fatal(err)
   }

}</lang>

Output:

Silence-Dogood.

Java

Translation of: Kotlin

<lang java>import java.io.IOException; import java.nio.charset.StandardCharsets; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.util.ArrayList; import java.util.List; import java.util.function.Predicate;

public class Processing {

   private static class UserInput {
       private char formFeed;
       private char lineFeed;
       private char tab;
       private char space;

       private UserInput(char formFeed, char lineFeed, char tab, char space) {
           this.formFeed = formFeed;
           this.lineFeed = lineFeed;
           this.tab = tab;
           this.space = space;
       }

       char getFormFeed() {
           return formFeed;
       }

       char getLineFeed() {
           return lineFeed;
       }

       char getTab() {
           return tab;
       }

       char getSpace() {
           return space;
       }
   }

   private static List<UserInput> getUserInput() {
       String h = "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 " +
           "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28";
       String[] s = h.split(" ");

       List<UserInput> uiList = new ArrayList<>();
       for (int idx = 0; idx + 3 < s.length; idx += 4) {
           char c0 = (char) Integer.parseInt(s[idx + 0]);
           char c1 = (char) Integer.parseInt(s[idx + 1]);
           char c2 = (char) Integer.parseInt(s[idx + 2]);
           char c3 = (char) Integer.parseInt(s[idx + 3]);

           UserInput userInput = new UserInput(c0, c1, c2, c3);
           uiList.add(userInput);
       }
       return uiList;
   }

   private static void decode(String fileName, List<UserInput> uiList) throws IOException {
       Path path = Paths.get(fileName);
       byte[] bytes = Files.readAllBytes(path);
       String text = new String(bytes, StandardCharsets.UTF_8);

       Predicate<UserInput> decode2 = (UserInput ui) -> {
           char f = 0;
           char l = 0;
           char t = 0;
           char s = 0;
           char ff = ui.getFormFeed();
           char lf = ui.getLineFeed();
           char tb = ui.getTab();
           char sp = ui.getSpace();

           for (char c : text.toCharArray()) {
               if (f == ff && l == lf && t == tb && s == sp) {
                   if (c == '!') {
                       return false;
                   }
                   System.out.print(c);
                   return true;
               }
               switch (c) {
                   case '\u000c':
                       f++;
                       l = 0;
                       t = 0;
                       s = 0;
                       break;
                   case '\n':
                       l++;
                       t = 0;
                       s = 0;
                       break;
                   case '\t':
                       t++;
                       s = 0;
                       break;
                   default:
                       s++;
                       break;
               }
           }

           return false;
       };

       for (UserInput ui : uiList) {
           if (!decode2.test(ui)) {
               break;
           }
       }
       System.out.println();
   }

   public static void main(String[] args) throws IOException {
       List<UserInput> uiList = getUserInput();
       decode("theRaven.txt", uiList);
   }

}</lang>

Output:

Silence-Dogood.

Julia

Customization is via adding to or deleting from the chars dictionary. <lang julia>@enum streamstate GET_FF GET_LF GET_TAB GET_CHAR ABORT chars = Dict(GET_FF => ['\f'], GET_LF => ['\n'], GET_TAB => ['\t'])

function stream_decode_jit(iostream)

   msg, state, ffcount, lfcount, tabcount, charcount = "", GET_FF, 0, 0, 0, 0
   while true
       if state == ABORT || eof(iostream)
           return msg
       end
       ch = read(iostream, Char)
       if state == GET_FF && ch in chars[GET_FF]
           ffcount += 1
           state = GET_LF
           lfcount = 0
       elseif state == GET_LF && ch in chars[GET_LF]
           if (lfcount += 1) == ffcount
               state = GET_TAB
               tabcount = 0
           end
       elseif state == GET_TAB && ch in chars[GET_TAB]
           if (tabcount += 1) == ffcount
               state = GET_CHAR
               charcount = 0
           end
       elseif state == GET_CHAR
           if (charcount += 1) == ffcount
               print(ch)
               msg *= ch
               if ch == '!'
                   state = ABORT
               else
                   state = GET_FF
               end
           end
       end
   end

end

stream_decode_jit(open("filename.txt", "r")) </lang>

Kotlin

Translation of: C++

<lang scala>// version 1.2.10

import java.io.File

data class UserInput(val formFeed: Int, val lineFeed: Int, val tab: Int, val space: Int)

fun getUserInput(): List<UserInput> {

   val h = "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 " +
           "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28"
   return h.split(' ').chunked(4).map {
       val (ff, lf, tb, sp) = it
       UserInput(ff.toInt(), lf.toInt(), tb.toInt(), sp.toInt())
   }

}

fun decode(fileName: String, uiList: List<UserInput>) {

   val text = File(fileName).readText()

   fun decode2(ui: UserInput): Boolean {
       var f = 0
       var l = 0
       var t = 0
       var s = 0
       val (ff, lf, tb, sp) = ui
       for (c in text) {
           if (f == ff && l == lf && t == tb && s == sp) {
               if (c == '!') return false
               print(c)
               return true
           }
           when (c) {
               '\u000c' -> { f++; l = 0; t = 0; s = 0 }
               '\n'     -> { l++; t = 0; s = 0 }
               '\t'     -> { t++; s = 0 }
               else     -> { s++ }
           }
       }
       return false
   }

   for (ui in uiList) {
       if (!decode2(ui)) break
   }
   println()

}

fun main(args: Array<String>) {

   val uiList = getUserInput()
   decode("theRaven.txt", uiList)

}</lang>

Output:

Silence-Dogood.

Perl

Translation of: Raku

Library: ntheory

<lang perl>use strict; use warnings; use feature 'say'; use feature 'state';

use ntheory qw/fromdigits todigitstring/;

my $key = 'perl5'; srand fromdigits($key,36) % 2**63;

my @stream;

sub stream {

   my($i) = shift;
   state @chars;
   push @chars, chr($_) for 14..127;
   $stream[$i] = $chars[rand 1+127-14] unless $stream[$i];

}

sub jit_encode {

   my($str) = shift;
   my $i = 0;
   my $last = 0;
   my $enc = ;
   for my $c (split , $str) {
       my $h;
       my $l = ;
       ++$i until $c eq stream($i);
       my $o = $i - $last;
       $l    = $o % 26;
       $h    = $o - $l if $o > 26;
       $l   += 10;
       $enc .= ($h ? uc todigitstring($h,36) : ) . lc todigitstring($l,36);
       $last = $i;
   }
   $enc

}

sub jit_decode {

   my($str) = shift;
   my @matches = $str =~ /((.*?) ([a-z]))/gx;
   my $dec = ;
   my $i = 0;
   for my $j (0 .. @matches/3 - 1) {
       my $o = ( fromdigits($matches[3*$j+1],36) - 10 // 0) +
               ( fromdigits($matches[3*$j+2],36)      // 0);
       $i   += $o;
       $dec .= $stream[$i];
   }
   $dec

}

my $enc = jit_encode('The slithey toves did gyre and gimble in the wabe'); say my $result = "Encoded\n$enc\n\nDecoded\n" . jit_decode($enc);</lang>

Output:

Encoded
bQh52yf9Ex2Wi4Cv1GcyoAUcBKbke3Mo5Ss2WybQlvQs1GviQc1GnQg5Sv26j1Gm26m3Mp26iQz78lQx2Wel1Gcs52y5Sds3Me26l52au1Gwe1Gl

Decoded
The slithey toves did gyre and gimble in the wabe

Phix

Translation of: C

Library: Phix/libcurl

-- demo/rosetta/BookCipher.exw
function decode(integer fn, sequence ui)
    integer {ff,lf,tab,sp} = ui,
             f = 0, l = 0, t = 0, s = 0
    while true do
        integer c = getc(fn)
        if c=-1 then return false end if
        if f==ff and l==lf and t==tab and s==sp then
            if c=='!' then return false end if
            puts(1,c)
            return true
        elsif c==#0C then
            f += 1
            {l, t, s} = {0, 0, 0}
        elsif c=='\n' then
            l += 1
            {t, s} = {0, 0}
        elsif c=='\t' then
            t += 1
            s = 0
        else
            s += 1
        end if
    end while
    return false
end function
 
include builtins\libcurl.e
 
procedure decodeFile(string filename, url, sequence code)
    if not file_exists(filename) then
        printf(1,"Downloading %s...\n",{filename})
        CURLcode res = curl_easy_get_file(url,"",filename) -- (no proxy)
        if res!=CURLE_OK then
            string error = sprintf("%d",res)
            if res=CURLE_COULDNT_RESOLVE_HOST then
                error &= " [CURLE_COULDNT_RESOLVE_HOST]"
            end if
            crash("Error %s downloading file\n", {error})
        end if  
    end if  
    integer fn = open(filename, "r")
    if fn=-1 then crash("could not open %s",{filename}) end if
    for i=1 to length(code) do
        if not decode(fn,code[i]) then exit end if
        if seek(fn, 0)!=SEEK_OK then crash("seek error") end if
    end for
    printf(1,"\n\n");
end procedure
 
constant code = {{0,18,0,0},
                 {0,68,0,1},
                 {0,100,0,32},
                 {0,114,0,45},
                 {0,38,0,26},
                 {0,16,0,21},
                 {0,17,0,59},
                 {0,11,0,29},
                 {0,102,0,0},
                 {0,10,0,50},
                 {0,39,0,42},
                 {0,33,0,50},
                 {0,46,0,54},
                 {0,76,0,47},
                 {0,84,2,28}}
decodeFile("theRaven.txt", "http://paulo-jorente.de/text/theRaven.txt", code)
{} = wait_key()

Output:

Silence-Dogood.

Python

Translation of: D

<lang python>import sys

class UserInput:

   def __init__(self,chunk):
       self.formFeed = int(chunk[0])
       self.lineFeed = int(chunk[1])
       self.tab = int(chunk[2])
       self.space = int(chunk[3])

   def __str__(self):
       return "(ff=%d; lf=%d; tb=%d; sp%d)" % (self.formFeed,self.lineFeed,self.tab,self.space)

def chunks(l,n):

   for i in xrange(0, len(l), n):
       yield l[i:i+n]

def getUserInput():

   h = "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 "\
       "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28"
   ha = h.split()
   return [UserInput(chunk) for chunk in chunks(ha, 4)]

def decode(filename,uiList):

   f = open(filename, "r")
   text = f.read()

   def decode2(ui):
       f = 0
       l = 0
       t = 0
       s = 0
       for c in text:
           if f == ui.formFeed and l == ui.lineFeed and t == ui.tab and s == ui.space:
               if c == '!':
                   return False
               sys.stdout.write(c)
               return True
           if c == '\u000c':
               f=f+1
               l=0
               t=0
               s=0
           elif c == '\n':
               l=l+1
               t=0
               s=0
           elif c == '\t':
               t=t+1
               s=0
           else:
               s=s+1
       return False

   for ui in uiList:
       if not decode2(ui):
           break
   print

1. 1. 1. 1. 1. Main #####

uiList = getUserInput() decode("theRaven.txt", uiList)</lang>

Output:

Silence-Dogood.

Racket

Translation of: Kotlin

<lang racket>#lang racket

(define user-input

 (~a "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 "
     "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28"))

(define content (file->string "theRaven.txt"))

(define (decode slice)

 (match-define (list ff lf tb sp) slice)
 (let loop ([f 0] [l 0] [t 0] [s 0] [xs (string->list content)])
   (define next (curryr loop (rest xs)))
   (match (first xs)
     [c #:when (and (= f ff) (= l lf) (= t tb) (= s sp)) c]
     [#\u000c   (next (add1 f) 0 0 0)]
     [#\newline (next f (add1 l) 0 0)]
     [#\tab     (next f l (add1 t) 0)]
     [_         (next f l t (add1 s))])))

(for ([slice (in-slice 4 (map string->number (string-split user-input)))])

 (define c (decode slice))
 #:break (char=? #\! c)
 (display c))</lang>

Input:

http://paulo-jorente.de/text/theRaven.txt

Output:

Silence-Dogood.

Raku

(formerly Perl 6)

Works with: Rakudo version 2019.03

This is a something of a toy encoder / decoder and probably shouldn't be used for anything serious.

Default encode/decode key is 'Raku' Feed it a pass phrase at the command line to use that instead.

Will handle any visible character in the ASCII range as well as space and new-line.

<lang perl6>#`[ Set srand to set the encode / decode "key". Need to use the same "key" and same implementation of Raku to encode / decode. Gain "security" by exchanging "keys" by a second channel. Default "key" is "Raku" ]

unit sub MAIN ($key = 'Raku');

srand $key.comb(/<.alnum>/).join.parse-base(36) % 2**63;

my @stream = (flat "\n", ' ' .. '~').roll(*);

sub jit-encode (Str $str) {

   my $i = 0;
   my $last = 0;
   my $enc = ;
   for $str.comb -> $c {
       my $h;
       my $l = ;
       ++$i until $i > 1 && $c eq @stream[$i];
       my $o = $i - $last;
       $l    = $o % 26;
       $h    = $o - $l if $o >= 26;
       $l   += 10;
       $enc ~= ($h ?? $h.base(36).uc !! ) ~ ($l.base(36).lc);
       $last = $i;
   }
   my $block = 60;
   $enc.comb($block).join: "\n"

}

sub jit-decode (Str $str is copy) {

   $str.=subst("\n", , :g);
   $str ~~ m:g/((.*?) (<:Ll>))/;
   my $dec = ;
   my $i = 0;
   for $/.List -> $l {
       my $o = ($l[0][1].Str.parse-base(36) - 10 // 0) +
               ($l[0][0].Str.parse-base(36) // 0);
       $i += $o;
       $dec ~= @stream[$i];
   }
   $dec

}

my $secret = q:to/END/; In my opinion, this task is pretty silly.

'Twas brillig, and the slithy toves

   Did gyre and gimble in the wabe.

!@#$%^&*()_+}{[].,><\|/?'";:1234567890 END

say "== Secret: ==\n$secret";

say "\n== Encoded: =="; say my $enc = jit-encode($secret);

say "\n== Decoded: =="; say jit-decode($enc);</lang>

== Secret: ==
In my opinion, this task is pretty silly.

'Twas brillig, and the slithy toves
    Did gyre and gimble in the wabe.

!@#$%^&*()_+}{[].,><\|/?'";:1234567890


== Encoded: ==
Qv26e26q1Gi2Ww5SiQr26h3Mk1GbQy52e1Gg6Ib52kQfQk26n26l26cQm26q
2Wk26vwme52qy6Ia1GuQfa3MbQxtd26aa3MvQu2Wuat26p2Wbe2Wc1Ga26g2
6h26pQha26h4Cf26jrz7Yz3MaA4h2WxFWf52zyg2WrQn2Wj26pQyQy78x1Gd
dk4Cu26k26qaaap26j26xqQf7Yr8Op3Me3Me5Sv1Ge1Gt2WxlQz5Si1GeQg4
CjQc5Sb2WbQo1GycQr1Gm1Gy1GsQei3MrQsai1Gq2WnQdt2Wj1Gff1Gg26le
2Wd1Go9Ek1Gm9Eh2Wb1Gd52h2WdQae4Chu3MeQd1Gg1Gw4CqbEGh52u2Wr1G
t52xhvQmx

== Decoded: ==
In my opinion, this task is pretty silly.

'Twas brillig, and the slithy toves
    Did gyre and gimble in the wabe.

!@#$%^&*()_+}{[].,><\|/?'";:1234567890

REXX

The input file used by this REXX program only contains one page;   it has no   FF   (formfeed)   characters in it),
and the injection of   FF   characters into the file would be like putting pencil marks into a holy book.   ☺ <lang rexx>/*REXX program extracts characters by using a book cipher (that is a text file). */ parse arg iFID . /*obtain optional name of file (book).*/ if iFID== | iFID=="," then iFID= 'JIT.TXT' /*Not specified? Then use the default.*/ $= 'abcdefghijklmnopqrstuvwxyz'; _=$; upper _; $= "0123456789"$ || _; $$=$ || xrange() prompt= '────────── enter four positive integers or Quit' pag=1; lin=1; FF= 'c'x /*assume start of page 1, line 1. */ @.= /*read the entire book from the file. */

   do  while  lines(iFID)\==0                   /*process lines from input stream(file)*/
   _= translate( linein(iFID), , '9'x)          /*obtain a single line from input file.*/
   if pos(FF, _)\==0  then do; pag=pag+1; lin=1 /*bump page counter; reset line counter*/
                           end                  /* [↑]  handle finding of FF (formfeed)*/
   @.pag.lin= _                                 /*obtain a single line from input file.*/
         lin= lin + 1                           /*bump the line counter.               */
   end   /*while*/                              /* [↑]  read the entire input stream.  */

?= /*define the phrase to be null (so far)*/

      do ask=0;       say prompt;       pull y  /*get just─in─time positional numbers. */
      if abbrev('QUIT', y, 1)  then exit 0      /*the user wants out of here, so exit. */
      y=space( translate(y, $, $$) )            /*allow any separator the user wants.  */
      parse var  y    a.1   a.2   a.3   a.4     /*parse the pertinent parameters.      */
      if words(y)>4   then do;    say 'too many parameters entered.'
                                  iterate  ask
                           end                  /*go and try again to obtain the parms.*/
        do k=1  for 4;  is#= datatype(a.k, 'W') /*validate  parms  {positive integers}.*/
        if is#  then a.k= a.k / 1               /*normalize the number (for indexing). */
        if is#  &  a.k>0  then iterate          /*found a good parameter?   Then skip. */
        say 'parameter '      k      " is missing or not a positive integer: "      a.k
        iterate  ask                            /*go and ask for another set of parms. */
        end   /*k*/                             /* [↑]  done with the validations.     */
      parse value a.1 a.2 a.3 a.4  with p L w c /*parse parameters for specific names. */
      x=substr( word( @.p.L, w), c,  1)         /*extract a character from the book.   */
      if x=='!'  then leave                     /*if the  stop  char was found,  done. */
      say right(x  '◄─── a letter', 46)         /*might as well echo char to terminal. */
      ?= ? || x                                 /*append the character to the phrase.  */
      end   /*j*/                               /* [↑]  display letters found in book. */

say '═════►'  ? /*stick a fork in it, we're all done. */</lang>

input   supplied to the console (terminal) by the user in response to the prompts,   (the commas are optional):

  1,   133,   4,   5
  1,    34,   9,   3
  1,  1377,   2,   2
  1,     4,   8,   4
  1,   265,   3,   5
  1,   413,  10,   2
  1,    10,  12,   1
  1,   144,  10,  10
  1,   571,   4,  12

input   (abbridged)

──────────enter four parameters  (all positive integers)   or   QUIT
  1,   133,   4,   5                            ◄■■■■■■■■■ user input (first reponse).     
                               s ◄─── a letter

    ∙
    ∙                                           (some prompts and reponses elided.)  
    ∙

──────────enter four parameters  (all positive integers)   or   QUIT
  1,   571,   4,  12                            ◄■■■■■■■■■ user input (ninth reponse). 
═════► so─true. 

The input file used (the IBM jargon file) in the above REXX program can be found here ───►   Just_in_time_processing_on_a_character_stream/REXX/JIT.TXT.

Tcl

Works with: Tcl version 8.6

<lang tcl>package require Tcl 8.6

oo::class create JustInTimeStreamExtract {

   variable map counter counters last
   constructor {{pageSeparator "\f"} {lineSeparator "\n"} {fieldSeparator "\t"}} {

dict set map $pageSeparator NextPage dict set map $lineSeparator NextLine dict set map $fieldSeparator NextField set counter 1 array set counters {page 0 line 0 field 0 char 0} set last ""

   }

   method emit {char} {

puts -nonewline $char set last $char

   }
   method finished {} {

if {$last ne "\n"} { puts "" }

   }

   method stream {{channel stdin} {length 1}} {

try { while 1 { set str [read $channel $length] if {[eof $channel]} break foreach c [split $str ""] { if {[dict exists $map $c]} { my [dict get $map $c] } else { my NextChar $c } } } } trap STOP {} { # Do nothing } my finished

   }

   method NextPage {} {

incr counters(page) array set counters {line 0 field 0 char 0}

   }
   method NextLine {} {

incr counters(line) array set counters {field 0 char 0}

   }
   method NextField {} {

incr counters(field) set counters(char) 0

   }
   method NextChar {char} {

incr counters(char) if {[my PrintThisOne?]} { if {$char eq "!"} { throw STOP "stop character found" } incr counter my emit $char array set counters {page 0 line 0 field 0 char 0} }

   }

   method PrintThisOne? {} {

tcl::mathop::== $counter $counters(page) $counters(line) $counters(field) $counters(char)

   }

}</lang> Demonstration of use: <lang tcl>[JustInTimeStreamExtract new] stream [open "sample.txt"]</lang>

Visual Basic .NET

Translation of: C#

<lang vbnet>Module Module1

   Structure UserInput
       ReadOnly FormFeed As Char
       ReadOnly LineFeed As Char
       ReadOnly Tab As Char
       ReadOnly Space As Char

       Sub New(ff As String, lf As String, tb As String, sp As String)
           FormFeed = ChrW(Integer.Parse(ff))
           LineFeed = ChrW(Integer.Parse(lf))
           Tab = ChrW(Integer.Parse(tb))
           Space = ChrW(Integer.Parse(sp))
       End Sub
   End Structure

   Function GetUserInput() As List(Of UserInput)
       Dim h = "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 " &
           "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28"
       Return h.Split(" ") _
           .Select(Function(x, idx) New With {x, idx}) _
           .GroupBy(Function(x) x.idx \ 4) _
           .Select(Function(g)
                       Dim ge = g.Select(Function(a) a.x).ToArray()
                       Return New UserInput(ge(0), ge(1), ge(2), ge(3))
                   End Function) _
                   .ToList()
   End Function

   Sub Decode(filename As String, uiList As List(Of UserInput))
       Dim text = IO.File.ReadAllText(filename)

       Dim Inc = Function(a As Char) As Char
                     Return ChrW(AscW(a) + 1)
                 End Function

       Dim DecodeImpl = Function(ui As UserInput) As Boolean
                            Dim f = ChrW(0)
                            Dim l = ChrW(0)
                            Dim t = ChrW(0)
                            Dim s = ChrW(0)

                            For Each c In text
                                If f = ui.FormFeed AndAlso l = ui.LineFeed AndAlso t = ui.Tab AndAlso s = ui.Space Then
                                    If c = "!" Then
                                        Return False
                                    End If
                                    Console.Write(c)
                                    Return True
                                End If
                                If vbFormFeed = c Then
                                    f = Inc(f)
                                    l = ChrW(0)
                                    t = ChrW(0)
                                    s = ChrW(0)
                                ElseIf vbLf = c Then
                                    l = Inc(l)
                                    t = ChrW(0)
                                    s = ChrW(0)
                                ElseIf vbTab = c Then
                                    t = Inc(t)
                                    s = ChrW(0)
                                Else
                                    s = Inc(s)
                                End If
                            Next

                            Return False
                        End Function

       For Each ui In uiList
           If Not DecodeImpl(ui) Then
               Exit For
           End If
       Next

       Console.WriteLine()
   End Sub

   Sub Main()
       Dim uiList = GetUserInput()
       Decode("theRaven.txt", uiList)
   End Sub

End Module</lang>

Output:

Silence-Dogood.

Wren

Translation of: Kotlin

Library: Wren-dynamic

Library: wren-seq

<lang ecmascript>import "io" for File import "/dynamic" for Tuple import "/seq" for Lst

var UserInput = Tuple.create("UserINput", ["formFeed", "lineFeed", "tab", "space"])

var getUserInput = Fn.new {

   var h = "0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 " +
           "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28"
   return Lst.chunks(h.split(" "), 4).map { |chunk|
       var flts = chunk.map { |c| Num.fromString(c) }.toList      
       return UserInput.new(flts[0], flts[1], flts[2], flts[3])
   }

}

var decode = Fn.new { |fileName, uiList|

   var text = File.read(fileName)

   var decode2 = Fn.new { |ui|
       var f = 0
       var l = 0
       var t = 0
       var s = 0
       for (c in text) {
           if (f == ui.formFeed && l == ui.lineFeed && t == ui.tab && s == ui.space) {
               if (c == "!") return false
               System.write(c)
               return true
           }
           if (c == "\f") {
               f = f + 1
               l = 0
               t = 0
               s = 0
           } else if (c == "\n") {
               l = l + 1
               t = 0
               s = 0
           } else if (c == "\t") {
               t = t + 1
               s = 0
           } else {
               s = s + 1
           }
       }
       return false
   }

   for (ui in uiList) if (!decode2.call(ui)) break
   System.print()

}

var uiList = getUserInput.call() decode.call("theRaven.txt", uiList)</lang>

Output:

Silence-Dogood.

zkl

Translation of: C++

<lang zkl>class FlyBy{

  fcn decode(file,tuplets){
     codePad:=File(file).read().mode(String); // blob of text
     tuplets.pump(Console.print, _decode.fp1(codePad));
     println();
   }
   fcn [private] _decode(idx,codePad){ // idx is (ff,lf,tab,chr) offset info codePad
      z:=-1;
      foreach n,c in (idx.zip(T("\f","\n","\t"))){
         do(n){ if(Void==(z=codePad.find(c,z+1))) return(Void.Stop); }
      }
      if(z==-1) z=0;  // (0,0,0,n)
      try{ return(codePad[z + idx[-1] + 1]) }catch{ return(Void.Stop) }
   }

}

fcn getUserInput{

  // I don't know a user would enter this but we have
  // a string of 4 item tuplets : (formfeeds, linefeeds, tabs, characters), ...
  // each tuplet is an offset into a code pad (text)
  h:="0 18 0 0 0 68 0 1 0 100 0 32 0 114 0 45 0 38 0 26 0 16 0 21 0 17 0 59 0 11 "
     "0 29 0 102 0 0 0 10 0 50 0 39 0 42 0 33 0 50 0 46 0 54 0 76 0 47 0 84 2 28";
  h.split(" ").pump(List,T(Void.Read,3),
     fcn(ff,lf,t,s){ vm.arglist.apply("toInt") });

}</lang> <lang zkl>input:=getUserInput();

  // our code pad is: http://paulo-jorente.de/text/theRaven.txt

FlyBy.decode("theRaven.txt",input);</lang>

Output:

Silence-Dogood.