Just in time processing on a character stream
Given a stream of characters containing the separator characters "formfeed", "linefeed", "tab" and "space", print out the ith character of the ith tab-field of the ith line of the ith page to reveal a secret password.
Stop processing immediately upon encountering a "!" found uniquely in this i,i,i,i position (lest the system self-destruct). The "!" may be found elsewhere however, in which case it should be ignored.
Ideally this can be generalised as follows:
- The separator characters are defined by a user-supplied array that can include additional or alternative separators, e.g. (formfeed, linefeed, ".", "," ," ",...).
- The selection criterion is generalised ith,ith,ith,ith to a boolean function of f(page,line,field,word,...) or f(ith,jth,kth,lth,mth,etc...)
Provide a reasonably interesting message to be decoded, e.g. "Silence-Dogood". Your choice.
This task was inspired by the movie "National Treasure", which refers to a "book cipher".
11l
T UserInput
Int formFeed
Int lineFeed
Int tab
Int space
F (chunk)
.formFeed = chunk[0]
.lineFeed = chunk[1]
.tab = chunk[2]
.space = chunk[3]
F String()
R ‘(ff=#.; lf=#.; tb=#.; sp#.)’.format(.formFeed, .lineFeed, .tab, .space)
F chunks(l, n)
[[Int]] r
L(i) (0 .< l.len).step(n)
r.append(l[i .+ n])
R r
F getUserInput()
V 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’
V ha = h.split(‘ ’).map(Int)
R chunks(ha, 4).map(chunk -> UserInput(chunk))
F decode(filename, uiList)
V f = File(filename)
V text = f.read()
F decode2(ui)
V f = 0
V l = 0
V t = 0
V s = 0
L(c) @text
I f == ui.formFeed & l == ui.lineFeed & t == ui.tab & s == ui.space
I c == ‘!’
R 0B
print(c, end' ‘’)
R 1B
I c.code == 0'C
f = f + 1
l = 0
t = 0
s = 0
E I c == "\n"
l = l + 1
t = 0
s = 0
E I c == "\t"
t = t + 1
s = 0
E
s = s + 1
R 0B
L(ui) uiList
I !decode2(ui)
L.break
print()
V uiList = getUserInput()
decode(‘theRaven.txt’, uiList)
- Output:
Silence-Dogood.
C
#include <stdbool.h>
#include <stdio.h>
#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;
}
- Output:
Silence-Dogood.
C#
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();
}
}
}
- Output:
Silence-Dogood.
C++
Text used to encode:The Raven - by E.A.Poe
#include <vector>
#include <iostream>
#include <fstream>
#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;
}
- Output:
Silence-Dogood.
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);
}
- Output:
Silence-Dogood.
FreeBASIC
Type UserInput
As Integer FormFeed
As Integer LineFeed
As Integer Tabulador
As Integer Espacio
End Type
Sub splitString(cad As String, delimiter As String, result() As String)
Dim As Integer start = 1
Dim As Integer finish
Dim As Integer index = 0
Do
finish = Instr(start, cad, delimiter)
If finish > 0 Then
Redim Preserve result(index)
result(index) = Mid(cad, start, finish - start)
start = finish + Len(delimiter)
index += 1
Else
Redim Preserve result(index)
result(index) = Mid(cad, start)
End If
Loop Until finish = 0
End Sub
Sub getUserInput(uiList() As UserInput)
Dim As 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"
Dim As String chunks()
splitString(h, " ", chunks())
Redim uiList(Ubound(chunks) \ 4)
For i As Integer = Lbound(chunks) To Ubound(chunks) Step 4
uiList(i \ 4).FormFeed = Val(chunks(i))
uiList(i \ 4).LineFeed = Val(chunks(i + 1))
uiList(i \ 4).Tabulador = Val(chunks(i + 2))
uiList(i \ 4).Espacio = Val(chunks(i + 3))
Next i
End Sub
Sub decode(fileName As String, uiList() As UserInput)
Dim As String c, text = ""
Dim As Integer ff = Freefile
If Open(fileName For Input As #ff) = 0 Then
While Not Eof(ff)
Dim linea As String
Line Input #ff, linea
text &= linea & Chr(10)
Wend
Close #ff
End If
Dim As Integer i, j, f, l, t, s
For i = Lbound(uiList) To Ubound(uiList)
f = 0
l = 0
t = 0
s = 0
For j = 1 To Len(text)
c = Mid(text, j, 1)
If f = uiList(i).FormFeed And l = uiList(i).LineFeed And t = uiList(i).Tabulador And s = uiList(i).Espacio Then
If c = "!" Then Exit Sub
Print c;
Exit For
End If
Select Case c
Case Chr(12) ' form feed
f += 1
l = 0
t = 0
s = 0
Case Chr(10) ' line feed
l += 1
t = 0
s = 0
Case Chr(9) ' tabulador
t += 1
s = 0
Case Else
s += 1
End Select
Next j
Next i
Print
End Sub
Dim As UserInput uiList()
getUserInput(uiList())
decode("theRaven.txt", uiList())
Sleep
- Output:
Silence-Dogood.
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)
}
}
- Output:
Silence-Dogood.
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);
}
}
- Output:
Silence-Dogood.
jq
Adapted from Wren
Works with gojq, the Go implementation of jq
# User input takes the form of quadtuples of integers: [formFeed, lineFeed, tab, space]
def getUserInput:
def nwise($n):
def n: if length <= $n then . else .[0:$n] , (.[$n:] | n) end;
n;
"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"
| split(" ") | map(tonumber) | nwise(4)
| {formFeed: .[0], lineFeed: .[1], tab: .[2], space: .[3]} ;
def emit_until(cond; stream):
label $out | stream | if cond then break $out else . end;
# Input should be the text as a (long) string
def decode($uiList):
def stream: explode[] | [.] | implode;
def decode2(ui):
. as $text
| label $out
| foreach stream as $c (
{ f: 0, l: 0, t: 0, s: 0 };
if .f == ui.formFeed and .l == ui.lineFeed and .t == ui.tab and .s == ui.space
then .out = $c
elif $c == "\f"
then .f += 1
| .l = 0
| .t = 0
| .s = 0
elif $c == "\n"
then .l += 1
| .t = 0
| .s = 0
elif $c == "\t"
then .t += 1
| .s = 0
else .s += 1
end;
if .out then .out, break $out else empty end )
// "" ;
decode2($uiList) ;
# Input: the text
[emit_until(. == "!"; getUserInput as $ui | decode($ui)) ] | add
- Output:
Invocation: jq -Rsr -f program.jq theRaven.txt
Silence-Dogood.
Julia
Customization is via adding to or deleting from the chars dictionary.
@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"))
Kotlin
// 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)
}
- Output:
Silence-Dogood.
Nim
With some modifications compared to the model.
import options, sequtils, strutils
type Position = tuple[ff, lf, tab, sp: int]
func buildUserInput(s: string): seq[Position] =
let valList = s.splitWhitespace().map(parseInt)
doAssert valList.len mod 4 == 0, "Number of values must be a multiple of four."
doAssert valList.allIt(it >= 0), "Expected non negative values."
let posList = valList.distribute(valList.len div 4)
result = posList.mapIt((ff: it[0], lf: it[1], tab: it[2], sp: it[3]))
proc decode(filename: string; uiList: seq[Position]): string =
func decode(text: string; ui: Position): Option[char] =
var f, l, t, s = 0
let (ff, lf, tab, sp) = ui
for c in text:
if f == ff and l == lf and t == tab and s == sp:
return if c == '!': none(char) else: some(c)
case c
of '\f': inc f; l = 0; t = 0; s = 0
of '\l': inc l; t = 0; s = 0
of '\t': inc t; s = 0
else: inc s
let text = filename.readFile()
for ui in uiList:
let c = text.decode(ui)
if c.isNone: break
result.add c.get()
const UiList = buildUserInput("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")
echo "theRaven.txt".decode(UiList)
- Output:
Silence-Dogood.
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);
- Output:
Encoded bQh52yf9Ex2Wi4Cv1GcyoAUcBKbke3Mo5Ss2WybQlvQs1GviQc1GnQg5Sv26j1Gm26m3Mp26iQz78lQx2Wel1Gcs52y5Sds3Me26l52au1Gwe1Gl Decoded The slithey toves did gyre and gimble in the wabe
Phix
-- 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
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
##### Main #####
uiList = getUserInput()
decode("theRaven.txt", uiList)
- Output:
Silence-Dogood.
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))
- Input:
http://paulo-jorente.de/text/theRaven.txt
- Output:
Silence-Dogood.
Raku
(formerly Perl 6)
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.
#`[
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($enc);
== Secret: == In my opinion, this task is pretty silly. 'Twas brillig, and the slithy toves Did gyre and gimble in the wabe. !@#$%^&*()_+}{[].,><\|/?'";: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. ☺
/*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. */
- 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
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)
}
}
Demonstration of use:
[JustInTimeStreamExtract new] stream [open "sample.txt"]
Visual Basic .NET
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
- Output:
Silence-Dogood.
Wren
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)
- Output:
Silence-Dogood.
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") });
}
input:=getUserInput();
// our code pad is: http://paulo-jorente.de/text/theRaven.txt
FlyBy.decode("theRaven.txt",input);
- Output:
Silence-Dogood.