Run-length encoding: Difference between revisions

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ENDWHILE

= o$</lang>

=={{header|Befunge}}==

Not the same format as in the example,it puts "n\n" at the beginning so you can pipe the output back in and receive the input.

Pipe the output of the program-it's more reliable.

<lang Befunge> ~"y"- ~$ v

<temp var for when char changes

format:

first,'n' and a newline. :

a char then a v _"n",v

number then a space continuously 9

example: 1

n > v ,+<

a5 b2

decoded:aaaaabb

the program is ended using decoder

Ctrl-C on linux,or alt-f4

on windows.copy the output >\v encoder

of the program somewhere ^_ $ v

to encode press y : > $11g:, v

to decode pipe file in >1-^ ~ v +1\<

the output of the encoder \ v< $ ^ .\_^

starts with n,this is so ^,:<\&~< _~:,>1>\:v>^

you can pipe it straight in ^ <

~

the spaces seem to be a annoying thing :

thanks to CCBI...if a interpreter dosen't 1

create them it's non-conforming and thus 1

the validity of this program is NOT affected p-

>^

--written by Gamemanj,for Rosettacode</lang>

=={{header|Bracmat}}==

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This example only works if there are no digits in the string to be encoded and then decoded.

<lang csharp> public static void Main(string[] args)

public static void Main(string[] args)

{

string input = "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW";

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}

return sb.ToString();

}

}</lang>

</lang>

Somewhat shorter, using Regex.Replace with MatchEvaluator (using C#2 syntax only):

<lang csharp>using System;

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(mapcat (fn [[_ n ch]] (repeat (Integer/parseInt n) ch)))

(apply str)))</lang>

=={{header|COBOL}}==

<lang cobol> >>SOURCE FREE

IDENTIFICATION DIVISION.

PROGRAM-ID. run-length-encoding.

ENVIRONMENT DIVISION.

CONFIGURATION SECTION.

REPOSITORY.

FUNCTION encode

FUNCTION decode

.

DATA DIVISION.

WORKING-STORAGE SECTION.

01 input-str PIC A(100).

01 encoded PIC X(200).

01 decoded PIC X(200).

PROCEDURE DIVISION.

ACCEPT input-str

MOVE encode(FUNCTION TRIM(input-str)) TO encoded

DISPLAY "Encoded: " FUNCTION TRIM(encoded)

DISPLAY "Decoded: " FUNCTION TRIM(decode(encoded))

.

END PROGRAM run-length-encoding.

IDENTIFICATION DIVISION.

FUNCTION-ID. encode.

DATA DIVISION.

LOCAL-STORAGE SECTION.

01 str-len PIC 9(3) COMP.

01 i PIC 9(3) COMP.

01 current-char PIC A.

01 num-chars PIC 9(3) COMP.

01 num-chars-disp PIC Z(3).

01 encoded-pos PIC 9(3) COMP VALUE 1.

LINKAGE SECTION.

01 str PIC X ANY LENGTH.

01 encoded PIC X(200).

PROCEDURE DIVISION USING str RETURNING encoded.

MOVE FUNCTION LENGTH(str) TO str-len

MOVE str (1:1) TO current-char

MOVE 1 TO num-chars

PERFORM VARYING i FROM 2 BY 1 UNTIL i > str-len

IF str (i:1) <> current-char

CALL "add-num-chars" USING encoded, encoded-pos,

CONTENT current-char, num-chars

MOVE str (i:1) TO current-char

MOVE 1 TO num-chars

ELSE

ADD 1 TO num-chars

END-IF

END-PERFORM

CALL "add-num-chars" USING encoded, encoded-pos, CONTENT current-char,

num-chars

.

END FUNCTION encode.

IDENTIFICATION DIVISION.

PROGRAM-ID. add-num-chars.

DATA DIVISION.

WORKING-STORAGE SECTION.

01 num-chars-disp PIC Z(3).

LINKAGE SECTION.

01 str PIC X(200).

01 current-pos PIC 9(3) COMP.

01 char-to-encode PIC X.

01 num-chars PIC 9(3) COMP.

PROCEDURE DIVISION USING str, current-pos, char-to-encode, num-chars.

MOVE num-chars TO num-chars-disp

MOVE FUNCTION TRIM(num-chars-disp) TO str (current-pos:3)

ADD FUNCTION LENGTH(FUNCTION TRIM(num-chars-disp)) TO current-pos

MOVE char-to-encode TO str (current-pos:1)

ADD 1 TO current-pos

.

END PROGRAM add-num-chars.

IDENTIFICATION DIVISION.

FUNCTION-ID. decode.

DATA DIVISION.

LOCAL-STORAGE SECTION.

01 encoded-pos PIC 9(3) COMP VALUE 1.

01 decoded-pos PIC 9(3) COMP VALUE 1.

01 num-of-char PIC 9(3) COMP VALUE 0.

LINKAGE SECTION.

01 encoded PIC X(200).

01 decoded PIC X(100).

PROCEDURE DIVISION USING encoded RETURNING decoded.

PERFORM VARYING encoded-pos FROM 1 BY 1

UNTIL encoded (encoded-pos:2) = SPACES OR encoded-pos > 200

IF encoded (encoded-pos:1) IS NUMERIC

COMPUTE num-of-char = num-of-char * 10

+ FUNCTION NUMVAL(encoded (encoded-pos:1))

ELSE

PERFORM UNTIL num-of-char = 0

MOVE encoded (encoded-pos:1) TO decoded (decoded-pos:1)

ADD 1 TO decoded-pos

SUBTRACT 1 FROM num-of-char

END-PERFORM

END-IF

END-PERFORM

.

END FUNCTION decode.</lang>

<pre>

WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW

Encoded: 12W1B12W3B24W1B14W

Decoded: WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW

</pre>

=={{header|CoffeeScript}}==

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=={{header|PL/I}}==

<lang pli>declare (c1, c2) character (1);

declare (c1, c2) character (1);

declare run_length fixed binary;

declare input file;

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end;

put edit ((c do i = 1 to run_length)) (a);

end;

end;</lang>

</lang>

=={{header|PowerBASIC}}==

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=={{header|R}}==

R has a built-in function, rle, for run length encoding. This modification allows input and output in the forms specified above.

<lang R>runlengthencoding <- function(x)

<lang rsplus>runlengthencoding <- function(x)

{

splitx <- unlist(strsplit(input, ""))

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runlengthencoding(input)</lang>

Similarly, inverse.rle provides decompression after a run length encoding.

<lang R>inverserunlengthencoding <- function(x)

<lang rsplus>inverserunlengthencoding <- function(x)

{

lengths <- as.numeric(unlist(strsplit(output, "[[:alpha:]]")))

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=={{header|REXX}}==

The task (input) rule was relaxed a bit as this program accepts upper- and lowercase input.

===~~encoding~~===

===Encoding===

<lang rexx>/*REXX program encodes a string by using a run-length scheme. */

parse arg x . /*normally, input would be a file*/

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say 'encoded=' y

/*stick a fork in it, we're done.*/</lang>

'''~~output~~''' when using default input:'

'''Output''' when using default input:

input= WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW

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</pre>

===~~decoding~~===

===Decoding===

<lang rexx>/*REXX program decodes a string by using a run-length scheme. */

parse arg x . /*normally, input would be a file*/

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say 'decoded=' y

/*stick a fork in it, we're done.*/</lang>

'''~~output~~''' when using the default input:

'''Output''' when using the default input:

input= 11WB11W2B23WB13W

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WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW

</pre>

=={{header|Befunge}}==

Not the same format as in the example,it puts "n\n" at the beginning so you can pipe the output back in and receive the input.

Pipe the output of the program-it's more reliable.

<lang Befunge> ~"y"- ~$ v

<temp var for when char changes

format:

first,'n' and a newline. :

a char then a v _"n",v

number then a space continuously 9

example: 1

n > v ,+<

a5 b2

decoded:aaaaabb

the program is ended using decoder

Ctrl-C on linux,or alt-f4

on windows.copy the output >\v encoder

of the program somewhere ^_ $ v

to encode press y : > $11g:, v

to decode pipe file in >1-^ ~ v +1\<

the output of the encoder \ v< $ ^ .\_^

starts with n,this is so ^,:<\&~< _~:,>1>\:v>^

you can pipe it straight in ^ <

~

the spaces seem to be a annoying thing :

thanks to CCBI...if a interpreter dosen't 1

create them it's non-conforming and thus 1

the validity of this program is NOT affected p-

>^

--written by Gamemanj,for Rosettacode</lang>