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http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Julia | Julia | using Images, FileIO, Netpbm
rgbimg = load("data/bitmapInputTest.ppm")
greyimg = Gray.(rgbimg)
save("data/bitmapOutputTest.ppm", greyimg) |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Kotlin | Kotlin | // Version 1.2.40
import java.awt.Color
import java.awt.Graphics
import java.awt.image.BufferedImage
import java.io.FileInputStream
import java.io.PushbackInputStream
import java.io.File
import javax.imageio.ImageIO
class BasicBitmapStorage(width: Int, height: Int) {
val image = BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR)
fun fill(c: Color) {
val g = image.graphics
g.color = c
g.fillRect(0, 0, image.width, image.height)
}
fun setPixel(x: Int, y: Int, c: Color) = image.setRGB(x, y, c.getRGB())
fun getPixel(x: Int, y: Int) = Color(image.getRGB(x, y))
fun toGrayScale() {
for (x in 0 until image.width) {
for (y in 0 until image.height) {
var rgb = image.getRGB(x, y)
val red = (rgb shr 16) and 0xFF
val green = (rgb shr 8) and 0xFF
val blue = rgb and 0xFF
val lumin = (0.2126 * red + 0.7152 * green + 0.0722 * blue).toInt()
rgb = (lumin shl 16) or (lumin shl 8) or lumin
image.setRGB(x, y, rgb)
}
}
}
}
fun PushbackInputStream.skipComment() {
while (read().toChar() != '\n') {}
}
fun PushbackInputStream.skipComment(buffer: ByteArray) {
var nl: Int
while (true) {
nl = buffer.indexOf(10) // look for newline at end of comment
if (nl != -1) break
read(buffer) // read another buffer full if newline not yet found
}
val len = buffer.size
if (nl < len - 1) unread(buffer, nl + 1, len - nl - 1)
}
fun Byte.toUInt() = if (this < 0) 256 + this else this.toInt()
fun main(args: Array<String>) {
// use file, output.ppm, created in the Bitmap/Write a PPM file task
val pbis = PushbackInputStream(FileInputStream("output.ppm"), 80)
pbis.use {
with (it) {
val h1 = read().toChar()
val h2 = read().toChar()
val h3 = read().toChar()
if (h1 != 'P' || h2 != '6' || h3 != '\n') {
println("Not a P6 PPM file")
System.exit(1)
}
val sb = StringBuilder()
while (true) {
val r = read().toChar()
if (r == '#') { skipComment(); continue }
if (r == ' ') break // read until space reached
sb.append(r.toChar())
}
val width = sb.toString().toInt()
sb.setLength(0)
while (true) {
val r = read().toChar()
if (r == '#') { skipComment(); continue }
if (r == '\n') break // read until new line reached
sb.append(r.toChar())
}
val height = sb.toString().toInt()
sb.setLength(0)
while (true) {
val r = read().toChar()
if (r == '#') { skipComment(); continue }
if (r == '\n') break // read until new line reached
sb.append(r.toChar())
}
val maxCol = sb.toString().toInt()
if (maxCol !in 0..255) {
println("Maximum color value is outside the range 0..255")
System.exit(1)
}
var buffer = ByteArray(80)
// get rid of any more opening comments before reading data
while (true) {
read(buffer)
if (buffer[0].toChar() == '#') {
skipComment(buffer)
}
else {
unread(buffer)
break
}
}
// read data
val bbs = BasicBitmapStorage(width, height)
buffer = ByteArray(width * 3)
var y = 0
while (y < height) {
read(buffer)
for (x in 0 until width) {
val c = Color(
buffer[x * 3].toUInt(),
buffer[x * 3 + 1].toUInt(),
buffer[x * 3 + 2].toUInt()
)
bbs.setPixel(x, y, c)
}
y++
}
// convert to grayscale and save to a file
bbs.toGrayScale()
val grayFile = File("output_gray.jpg")
ImageIO.write(bbs.image, "jpg", grayFile)
}
}
} |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #360_Assembly | 360 Assembly | FALSE DC X'00'
TRUE DC X'FF' |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #6502_Assembly | 6502 Assembly | clr bit ; clears
setb bit ; sets |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Red | Red |
Red ["Ceasar Cipher"]
rot: func [
char [char!]
key [number!]
ofs [char!]
][
to-char key + char - ofs // 26 + ofs
]
caesar: function [
src [string!]
key [integer!]
][
lower: charset [#"a" - #"z"]
upper: charset [#"A" - #"Z"]
parse src [
any [
change s: [lower (o: #"a") | upper (o: #"A")] (rot s/1 key o)
| skip
]
]
src
]
encrypt: :caesar
decrypt: func spec-of :caesar [caesar src negate key]
|
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Delphi | Delphi |
program Bitwise_IO;
{$APPTYPE CONSOLE}
uses
System.SysUtils,
System.Classes;
type
TBitReader = class
private
readData: Cardinal;
startPosition: Integer;
endPosition: Integer;
Stream: TStream;
procedure Align;
function BaseStream: TStream;
procedure EnsureData(bitCount: Integer);
function GetInBuffer: Integer;
public
constructor Create(sm: TStream);
function Read(bitCount: Integer): Integer;
function ReadBit: Boolean;
end;
TBitWriter = class
private
data: Byte;
dataLength: Integer;
Stream: TStream;
procedure Align;
function BaseStream: TStream;
function BitsToAligment: Integer;
public
constructor Create(sm: TStream);
procedure Write(value, length: Integer);
procedure WriteBit(value: Boolean);
end;
function TBitReader.GetInBuffer: Integer;
begin
result := endPosition - startPosition;
end;
function TBitReader.BaseStream: TStream;
begin
result := stream;
end;
constructor TBitReader.Create(sm: TStream);
begin
Stream := sm;
end;
procedure TBitReader.EnsureData(bitCount: Integer);
var
readBits: Integer;
b: Byte;
begin
readBits := bitCount - GetInBuffer;
while readBits > 0 do
begin
BaseStream.Read(b, 1);
readData := readData or (b shl endPosition);
endPosition := endPosition + 8;
readBits := readBits - 8;
end;
end;
function TBitReader.ReadBit: Boolean;
begin
Exit(Read(1) > 0);
end;
function TBitReader.Read(bitCount: Integer): Integer;
begin
EnsureData(bitCount);
result := (readData shr startPosition) and ((1 shl bitCount) - 1);
startPosition := startPosition + bitCount;
if endPosition = startPosition then
begin
endPosition := ord(startPosition = 0);
readData := 0;
end
else if (startPosition >= 8) then
begin
readData := readData shr startPosition;
endPosition := endPosition - startPosition;
startPosition := 0;
end;
end;
procedure TBitReader.Align;
begin
endPosition := ord(startPosition = 0);
readData := 0;
end;
function TBitWriter.BaseStream: TStream;
begin
Exit(stream);
end;
function TBitWriter.BitsToAligment: Integer;
begin
Exit((32 - dataLength) mod 8);
end;
constructor TBitWriter.Create(sm: TStream);
begin
Stream := sm;
end;
procedure TBitWriter.WriteBit(value: Boolean);
begin
self.Write(ord(value), 1);
end;
procedure TBitWriter.Write(value, length: Integer);
var
currentData: Cardinal;
currentLength: Integer;
begin
currentData := data or (value shl dataLength);
currentLength := dataLength + length;
while currentLength >= 8 do
begin
BaseStream.Write(currentData, 1);
currentData := currentData shr 8;
currentLength := currentLength - 8;
end;
data := currentData;
dataLength := currentLength;
end;
procedure TBitWriter.Align;
begin
if dataLength > 0 then
begin
BaseStream.Write(data, 1);
data := 0;
dataLength := 0;
end;
end;
var
ms: TMemoryStream;
writer: TBitWriter;
reader: TBitReader;
begin
ms := TMemoryStream.create();
writer := TBitWriter.create(ms);
writer.WriteBit(true);
writer.Write(5, 3);
writer.Write($0155, 11);
writer.Align();
ms.Position := 0;
reader := TBitReader.create(ms);
writeln(reader.ReadBit());
writeln(reader.Read(3));
writeln(format('0x%.4x', [reader.Read(11)]));
reader.Align();
ms.Free;
writer.Free;
reader.Free;
Readln;
end. |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Euphoria | Euphoria | constant dimx = 800, dimy = 800
constant fn = open("first.ppm","wb") -- b - binary mode
sequence color
printf(fn, "P6\n%d %d\n255\n", {dimx,dimy})
for j = 0 to dimy-1 do
for i = 0 to dimx-1 do
color = {
remainder(i,256), -- red
remainder(j,256), -- green
remainder(i*j,256) -- blue
}
puts(fn,color)
end for
end for
close(fn) |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #FBSL | FBSL | #ESCAPECHARS ON
DIM bmpin = ".\\LenaClr.bmp", ppmout = ".\\Lena.ppm", bmpblob = 54 ' Size of BMP file headers
FILEGET(FILEOPEN(bmpin, BINARY), FILELEN(bmpin)): FILECLOSE(FILEOPEN) ' Fill buffer
DIM ppmheader AS STRING * 256, breadth, height
LET(breadth, height) = 128 ' Image width and height
SPRINTF(ppmheader, "P6\n%d %d\n255\n", breadth, height) ' Create PPM file header
DIM ppmdata AS STRING * (STRLEN(ppmheader) + FILELEN - bmpblob)
DIM head = @ppmdata + STRLEN, tail = @FILEGET + FILELEN - breadth * 3 - 2 ' Start of last scanline
ppmdata = ppmheader ' Copy PPM file header
WHILE tail >= @FILEGET + bmpblob ' Flip upside down
FOR DIM w = 0 TO (breadth - 1) * 3 STEP 3
POKE(head + 0 + w, CHR(PEEK(tail + 2 + w, 1))) ' Swap R
POKE(head + 1 + w, CHR(PEEK(tail + 1 + w, 1))) ' Keep G
POKE(head + 2 + w, CHR(PEEK(tail + 0 + w, 1))) ' Swap B
NEXT
INCR(head, breadth * 3): DECR(tail, breadth * 3) ' Next scanline
WEND
FILEPUT(FILEOPEN(ppmout, BINARY_NEW), ppmdata): FILECLOSE(FILEOPEN) |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Lua | Lua | function Read_PPM( filename )
local fp = io.open( filename, "rb" )
if fp == nil then return nil end
local data = fp:read( "*line" )
if data ~= "P6" then return nil end
repeat
data = fp:read( "*line" )
until string.find( data, "#" ) == nil
local image = {}
local size_x, size_y
size_x = string.match( data, "%d+" )
size_y = string.match( data, "%s%d+" )
data = fp:read( "*line" )
if tonumber(data) ~= 255 then return nil end
for i = 1, size_x do
image[i] = {}
end
for j = 1, size_y do
for i = 1, size_x do
image[i][j] = { string.byte( fp:read(1) ), string.byte( fp:read(1) ), string.byte( fp:read(1) ) }
end
end
fp:close()
return image
end |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #68000_Assembly | 68000 Assembly | clr bit ; clears
setb bit ; sets |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #8051_Assembly | 8051 Assembly | clr bit ; clears
setb bit ; sets |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Retro | Retro | {{
variable offset
: rotate ( cb-c ) tuck - @offset + 26 mod + ;
: rotate? ( c-c )
dup 'a 'z within [ 'a rotate ] ifTrue
dup 'A 'Z within [ 'A rotate ] ifTrue ;
---reveal---
: ceaser ( $n-$ )
!offset dup [ [ @ rotate? ] sip ! ] ^types'STRING each@ ;
}}
( Example )
"THEYBROKEOURCIPHEREVERYONECANREADTHIS" 3 ceaser ( returns encrypted string )
23 ceaser ( returns decrypted string ) |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Erlang | Erlang | -module(bitwise_io).
-compile([export_all]).
%% Erlang allows for easy manipulation of bitstrings. Here I'll
%% present a function that can take a message of 8-bit ASCII
%% characters and remove the MSB, leaving the same message in 7-bits.
compress(Message) ->
<< <<X:7>> || <<X:8>> <= Message >>.
%% Here we decompress the message.
decompress(Message) ->
<< <<X:8>> || <<X:7>> <= Message >>.
%% Now a test to demonstrate that this conversion works:
test_bitstring_conversion() ->
Message = <<"Hello, Rosetta Code!">>,
io:format("~p: ~B~n",[Message, bit_size(Message)]),
Compressed = compress(Message),
io:format("~p: ~B~n",[Compressed, bit_size(Compressed)]),
Decompressed = decompress(Compressed),
io:format("~p: ~B~n",[Decompressed, bit_size(Decompressed)]),
io:format("~p = ~p ? ~p~n",[Message, Decompressed,
Message =:= Decompressed]).
%% Now to show this on file output, we'll write the compressed version
%% to a file. Now, erlang's file:write_file expects objects that are
%% multiples of 8bits. We'll add padding to allow the writing to
%% complete, and then discard the padding when reading the file back
%% in.
test_file_io() ->
Message = <<"Hello, Rosetta Code!">>,
FileName = "bitwise_io.dat",
Compressed = compress(Message),
PaddingSize = (8 - (bit_size(Compressed) rem 8)) rem 8,
PaddedCompressed = <<Compressed:(bit_size(Compressed))/bitstring,
0:PaddingSize>>,
file:write_file(FileName,PaddedCompressed),
{ok, ReadIn} = file:read_file(FileName),
UnpaddedSize = bit_size(ReadIn) - 7,
Unpadded =
case UnpaddedSize rem 7 =:= 0 of
true ->
<<T:(UnpaddedSize)/bitstring,_:7>> = ReadIn,
T;
false ->
<< <<X:7>> || <<X:7>> <= ReadIn >>
end,
Decompressed = decompress(Unpadded),
io:format("~p~n",[Decompressed]). |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Forth | Forth | : write-ppm { bmp fid -- }
s" P6" fid write-line throw
bmp bdim swap
0 <# bl hold #s #> fid write-file throw
0 <# #s #> fid write-line throw
s" 255" fid write-line throw
bmp bdata bmp bdim * pixels
bounds do
i 3 fid write-file throw
pixel +loop ;
s" red.ppm" w/o create-file throw
test over write-ppm
close-file throw |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Fortran | Fortran | program main
use rgbimage_m
implicit none
integer :: nx, ny, i, j, k
type(rgbimage) :: im
! init image of height nx, width ny
nx = 400
ny = 300
call im%init(nx, ny)
! set some random pixel data
do i = 1, nx
do j = 1, ny
call im%set_pixel(i, j, [(nint(rand()*255), k=1,3)])
end do
end do
! output image into file
call im%write('fig.ppm')
end program |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #M2000_Interpreter | M2000 Interpreter |
Module Checkit {
Function Bitmap {
If match("NN") then {
Read x as long, y as long
} else.if Match("N") Then {
\\ is a file?
Read f
if not Eof(f) then {
Line Input #f, p3$
If p3$="P3" Then {
Line Input #f, Comment$
if left$(Comment$,1)="#" then {
Line Input #f, Dimension$
} else Dimension$=Comment$
long x=Val(piece$(Dimension$," ")(0))
long y=Val(piece$(Dimension$," ")(1))
do {
Line Input #f, P255$
} until left$(P255$, 1)<>"#"
If not P255$="255" then Error "Not proper ppm format"
}
}
} else Error "No proper arguments"
if x<1 or y<1 then Error "Wrong dimensions"
structure rgb {
red as byte
green as byte
blue as byte
}
m=len(rgb)*x mod 4
if m>0 then m=4-m ' add some bytes to raster line
m+=len(rgb) *x
Structure rasterline {
{
pad as byte*m
}
\\ union pad+hline
hline as rgb*x
}
Structure Raster {
magic as integer*4
w as integer*4
h as integer*4
lines as rasterline*y
}
Buffer Clear Image1 as Raster
\\ 24 chars as header to be used from bitmap render build in functions
Return Image1, 0!magic:="cDIB", 0!w:=Hex$(x,2), 0!h:=Hex$(y, 2)
\\ fill white (all 255)
\\ Str$(string) convert to ascii, so we get all characters from words width to byte width
if not valid(f) then Return Image1, 0!lines:=Str$(String$(chrcode$(255), Len(rasterline)*y))
Buffer Clear Pad as Byte*4
SetPixel=Lambda Image1, Pad,aLines=Len(Raster)-Len(Rasterline), blines=-Len(Rasterline) (x, y, c) ->{
where=alines+3*x+blines*y
if c>0 then c=color(c)
c-!
Return Pad, 0:=c as long
Return Image1, 0!where:=Eval(Pad, 2) as byte, 0!where+1:=Eval(Pad, 1) as byte, 0!where+2:=Eval(Pad, 0) as byte
}
GetPixel=Lambda Image1,aLines=Len(Raster)-Len(Rasterline), blines=-Len(Rasterline) (x,y) ->{
where=alines+3*x+blines*y
=color(Eval(image1, where+2 as byte), Eval(image1, where+1 as byte), Eval(image1, where as byte))
}
StrDib$=Lambda$ Image1, Raster -> {
=Eval$(Image1, 0, Len(Raster))
}
CopyImage=Lambda Image1 (image$) -> {
if left$(image$,12)=Eval$(Image1, 0, 24 ) Then {
Return Image1, 0:=Image$
} Else Error "Can't Copy Image"
}
Export2File=Lambda Image1, x, y (f) -> {
\\ use this between open and close
Print #f, "P3"
Print #f,"# Created using M2000 Interpreter"
Print #f, x;" ";y
Print #f, 255
x2=x-1
where=24
For y1= 0 to y-1 {
a$=""
For x1=0 to x2 {
Print #f, a$;Eval(Image1, where+2 as byte);" ";
Print #f, Eval(Image1, where+1 as byte);" ";
Print #f, Eval(Image1, where as byte);
where+=3
a$=" "
}
Print #f
m=where mod 4
if m<>0 then where+=4-m
}
}
if valid(F) then {
'load RGB values form file
x0=x-1
where=24
For y1=y-1 to 0 {
do {
Line Input #f, aline$
} until left$(aline$,1)<>"#"
flush ' empty stack
Stack aline$ ' place all values to stack as FIFO
For x1=0 to x0 {
\\ now read from stack using Number
Return Image1, 0!where+2:=Number as byte, 0!where+1:=Number as byte, 0!where:=Number as byte
where+=3
}
m=where mod 4
if m<>0 then where+=4-m
}
}
Group Bitmap {
SetPixel=SetPixel
GetPixel=GetPixel
Image$=StrDib$
Copy=CopyImage
ToFile=Export2File
}
=Bitmap
}
A=Bitmap(10, 10)
Call A.SetPixel(5,5, color(128,0,255))
Open "A.PPM" for Output as #F
Call A.ToFile(F)
Close #f
Open "A.PPM" for Input as #F
Try {
C=Bitmap(f)
Copy 400*twipsx,200*twipsy use C.Image$()
}
Close #f
' is the same as this one
Open "A.PPM" for Input as #F
Line Input #f, p3$
If p3$="P3" Then {
Line Input #f, Comment$
if left$(Comment$,1)="#" then {
Line Input #f, Dimension$
} else Dimension$=Comment$
Long x=Val(piece$(Dimension$," ")(0))
Long y=Val(piece$(Dimension$," ")(1))
do {
Line Input #f, P255$
} until left$(P255$, 1)<>"#"
If not P255$="255" then Error "Not proper ppm format"
B=Bitmap(x, y)
x0=x-1
For y1=y-1 to 0 {
do {
Line Input #f, aline$
} until left$(aline$,1)<>"#"
flush ' empty stack
Stack aline$ ' place all values to stack as FIFO
For x1=0 to x0 {
\\ now read from stack
Read red, green, blue
Call B.setpixel(x1, y1, Color(red, green, blue))
}
}
}
Close #f
If valid("B") then Copy 200*twipsx,200*twipsy use B.Image$()
}
Checkit
|
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Mathematica.2F_Wolfram_Language | Mathematica/ Wolfram Language | Import["file.ppm","PPM"]
|
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #8th | 8th |
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program boolean.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ FALSE, 0 // or other value
.equ TRUE, 1 // or other value
/*******************************************/
/* Initialized data */
/*******************************************/
.data
szMessTrue: .asciz "The value is true.\n"
szMessFalse: .asciz "The value is false.\n"
/*******************************************/
/* UnInitialized data */
/*******************************************/
.bss
/*******************************************/
/* code section */
/*******************************************/
.text
.global main
main: // entry of program
mov x0,0
//mov x0,#1 //uncomment pour other test
cmp x0,TRUE
bne 1f
// value true
ldr x0,qAdrszMessTrue
bl affichageMess
b 100f
1: // value False
ldr x0,qAdrszMessFalse
bl affichageMess
100: // standard end of the program */
mov x0,0 // return code
mov x8,EXIT // request to exit program
svc 0 // perform the system call
qAdrszMessTrue: .quad szMessTrue
qAdrszMessFalse: .quad szMessFalse
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
|
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #AArch64_Assembly | AArch64 Assembly |
/* ARM assembly AARCH64 Raspberry PI 3B */
/* program boolean.s */
/*******************************************/
/* Constantes file */
/*******************************************/
/* for this file see task include a file in language AArch64 assembly*/
.include "../includeConstantesARM64.inc"
.equ FALSE, 0 // or other value
.equ TRUE, 1 // or other value
/*******************************************/
/* Initialized data */
/*******************************************/
.data
szMessTrue: .asciz "The value is true.\n"
szMessFalse: .asciz "The value is false.\n"
/*******************************************/
/* UnInitialized data */
/*******************************************/
.bss
/*******************************************/
/* code section */
/*******************************************/
.text
.global main
main: // entry of program
mov x0,0
//mov x0,#1 //uncomment pour other test
cmp x0,TRUE
bne 1f
// value true
ldr x0,qAdrszMessTrue
bl affichageMess
b 100f
1: // value False
ldr x0,qAdrszMessFalse
bl affichageMess
100: // standard end of the program */
mov x0,0 // return code
mov x8,EXIT // request to exit program
svc 0 // perform the system call
qAdrszMessTrue: .quad szMessTrue
qAdrszMessFalse: .quad szMessFalse
/********************************************************/
/* File Include fonctions */
/********************************************************/
/* for this file see task include a file in language AArch64 assembly */
.include "../includeARM64.inc"
|
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #REXX | REXX | /*REXX program supports the Caesar cypher for the Latin alphabet only, no punctuation */
/*──────────── or blanks allowed, all lowercase Latin letters are treated as uppercase.*/
parse arg key .; arg . p /*get key & uppercased text to be used.*/
p= space(p, 0) /*elide any and all spaces (blanks). */
say 'Caesar cypher key:' key /*echo the Caesar cypher key to console*/
say ' plain text:' p /* " " plain text " " */
y= Caesar(p, key); say ' cyphered:' y /* " " cyphered text " " */
z= Caesar(y,-key); say ' uncyphered:' z /* " " uncyphered text " " */
if z\==p then say "plain text doesn't match uncyphered cyphered text."
exit 0 /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
Caesar: procedure; arg s,k; @= 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
ak= abs(k) /*obtain the absolute value of the key.*/
L= length(@) /*obtain the length of the @ string. */
if ak>length(@)-1 | k==0 then call err k 'key is invalid.'
_= verify(s, @) /*any illegal characters specified ? */
if _\==0 then call err 'unsupported character:' substr(s, _, 1)
if k>0 then ky= k + 1 /*either cypher it, or ··· */
else ky= L + 1 - ak /* decypher it. */
return translate(s, substr(@ || @, ky, L), @) /*return the processed text.*/
/*──────────────────────────────────────────────────────────────────────────────────────*/
err: say; say '***error***'; say; say arg(1); say; exit 13 |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Forth | Forth | \ writing
: init-write ( -- b m ) 0 128 ;
: flush-bits ( b m -- 0 128 ) drop emit init-write ;
: ?flush-bits ( b m -- b' m' ) dup 128 < if flush-bits then ;
: write-bit ( b m f -- b' m' )
if tuck or swap then
2/ dup 0= if flush-bits then ;
\ reading
: init-read ( -- b m ) key 128 ;
: eof? ( b m -- b m f ) dup if false else key? 0= then ;
: read-bit ( b m -- b' m' f )
dup 0= if 2drop init-read then
2dup and swap 2/ swap ; |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Go | Go | // Package bit provides bit-wise IO to an io.Writer and from an io.Reader.
package bit
import (
"bufio"
"errors"
"io"
)
// Order specifies the bit ordering within a byte stream.
type Order int
const (
// LSB is for Least Significant Bits first
LSB Order = iota
// MSB is for Most Significant Bits first
MSB
)
// ==== Writing / Encoding ====
type writer interface {
io.ByteWriter
Flush() error
}
// Writer implements bit-wise writing to an io.Writer.
type Writer struct {
w writer
order Order
write func(uint32, uint) error // writeLSB or writeMSB
bits uint32
nBits uint
err error
}
// writeLSB writes `width` bits of `c` in LSB order.
func (w *Writer) writeLSB(c uint32, width uint) error {
w.bits |= c << w.nBits
w.nBits += width
for w.nBits >= 8 {
if err := w.w.WriteByte(uint8(w.bits)); err != nil {
return err
}
w.bits >>= 8
w.nBits -= 8
}
return nil
}
// writeMSB writes `width` bits of `c` in MSB order.
func (w *Writer) writeMSB(c uint32, width uint) error {
w.bits |= c << (32 - width - w.nBits)
w.nBits += width
for w.nBits >= 8 {
if err := w.w.WriteByte(uint8(w.bits >> 24)); err != nil {
return err
}
w.bits <<= 8
w.nBits -= 8
}
return nil
}
// WriteBits writes up to 16 bits of `c` to the underlying writer.
// Even for MSB ordering the bits are taken from the lower bits of `c`.
// (e.g. WriteBits(0x0f,4) writes four 1 bits).
func (w *Writer) WriteBits(c uint16, width uint) error {
if w.err == nil {
w.err = w.write(uint32(c), width)
}
return w.err
}
var errClosed = errors.New("bit reader/writer is closed")
// Close closes the writer, flushing any pending output.
// It does not close the underlying writer.
func (w *Writer) Close() error {
if w.err != nil {
if w.err == errClosed {
return nil
}
return w.err
}
// Write the final bits (zero padded).
if w.nBits > 0 {
if w.order == MSB {
w.bits >>= 24
}
if w.err = w.w.WriteByte(uint8(w.bits)); w.err != nil {
return w.err
}
}
w.err = w.w.Flush()
if w.err != nil {
return w.err
}
// Make any future calls to Write return errClosed.
w.err = errClosed
return nil
}
// NewWriter returns a new bit Writer that writes completed bytes to `w`.
func NewWriter(w io.Writer, order Order) *Writer {
bw := &Writer{order: order}
switch order {
case LSB:
bw.write = bw.writeLSB
case MSB:
bw.write = bw.writeMSB
default:
bw.err = errors.New("bit writer: unknown order")
return bw
}
if byteWriter, ok := w.(writer); ok {
bw.w = byteWriter
} else {
bw.w = bufio.NewWriter(w)
}
return bw
}
// ==== Reading / Decoding ====
// Reader implements bit-wise reading from an io.Reader.
type Reader struct {
r io.ByteReader
bits uint32
nBits uint
read func(width uint) (uint16, error) // readLSB or readMSB
err error
}
func (r *Reader) readLSB(width uint) (uint16, error) {
for r.nBits < width {
x, err := r.r.ReadByte()
if err != nil {
return 0, err
}
r.bits |= uint32(x) << r.nBits
r.nBits += 8
}
bits := uint16(r.bits & (1<<width - 1))
r.bits >>= width
r.nBits -= width
return bits, nil
}
func (r *Reader) readMSB(width uint) (uint16, error) {
for r.nBits < width {
x, err := r.r.ReadByte()
if err != nil {
return 0, err
}
r.bits |= uint32(x) << (24 - r.nBits)
r.nBits += 8
}
bits := uint16(r.bits >> (32 - width))
r.bits <<= width
r.nBits -= width
return bits, nil
}
// ReadBits reads up to 16 bits from the underlying reader.
func (r *Reader) ReadBits(width uint) (uint16, error) {
var bits uint16
if r.err == nil {
bits, r.err = r.read(width)
}
return bits, r.err
}
// Close closes the reader.
// It does not close the underlying reader.
func (r *Reader) Close() error {
if r.err != nil && r.err != errClosed {
return r.err
}
r.err = errClosed
return nil
}
// NewReader returns a new bit Reader that reads bytes from `r`.
func NewReader(r io.Reader, order Order) *Reader {
br := new(Reader)
switch order {
case LSB:
br.read = br.readLSB
case MSB:
br.read = br.readMSB
default:
br.err = errors.New("bit writer: unknown order")
return br
}
if byteReader, ok := r.(io.ByteReader); ok {
br.r = byteReader
} else {
br.r = bufio.NewReader(r)
}
return br
} |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #GAP | GAP | # Dirty implementation
# Only P3 format, an image is a list of 3 matrices (r, g, b)
# Max color is always 255
WriteImage := function(name, img)
local f, r, g, b, i, j, maxcolor, nrow, ncol, dim;
f := OutputTextFile(name, false);
r := img[1];
g := img[2];
b := img[3];
dim := DimensionsMat(r);
nrow := dim[1];
ncol := dim[2];
maxcolor := 255;
WriteLine(f, "P3");
WriteLine(f, Concatenation(String(ncol), " ", String(nrow), " ", String(maxcolor)));
for i in [1 .. nrow] do
for j in [1 .. ncol] do
WriteLine(f, Concatenation(String(r[i][j]), " ", String(g[i][j]), " ", String(b[i][j])));
od;
od;
CloseStream(f);
end;
PutPixel := function(img, i, j, color)
img[1][i][j] := color[1];
img[2][i][j] := color[2];
img[3][i][j] := color[3];
end;
GetPixel := function(img, i, j)
return [img[1][i][j], img[2][i][j], img[3][i][j]];
end;
NewImage := function(nrow, ncol, color)
local r, g, b;
r := color[1] + NullMat(nrow, ncol);
g := color[2] + NullMat(nrow, ncol);
b := color[3] + NullMat(nrow, ncol);
return [r, g, b];
end;
# Reproducing the example from Wikipedia
black := [ 0, 0, 0 ];
g := NewImage(2, 3, black);
PutPixel(g, 1, 1, [255, 0, 0]);
PutPixel(g, 1, 2, [0, 255, 0]);
PutPixel(g, 1, 3, [0, 0, 255]);
PutPixel(g, 2, 1, [255, 255, 0]);
PutPixel(g, 2, 2, [255, 255, 255]);
PutPixel(g, 2, 3, [0, 0, 0]);
WriteImage("example.ppm", g); |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Go | Go | package raster
import (
"fmt"
"io"
"os"
)
// WriteTo outputs 8-bit P6 PPM format to an io.Writer.
func (b *Bitmap) WritePpmTo(w io.Writer) (err error) {
// magic number
if _, err = fmt.Fprintln(w, "P6"); err != nil {
return
}
// comments
for _, c := range b.Comments {
if _, err = fmt.Fprintln(w, c); err != nil {
return
}
}
// x, y, depth
_, err = fmt.Fprintf(w, "%d %d\n255\n", b.cols, b.rows)
if err != nil {
return
}
// raster data in a single write
b3 := make([]byte, 3*len(b.px))
n1 := 0
for _, px := range b.px {
b3[n1] = px.R
b3[n1+1] = px.G
b3[n1+2] = px.B
n1 += 3
}
if _, err = w.Write(b3); err != nil {
return
}
return
}
// WriteFile writes to the specified filename.
func (b *Bitmap) WritePpmFile(fn string) (err error) {
var f *os.File
if f, err = os.Create(fn); err != nil {
return
}
if err = b.WritePpmTo(f); err != nil {
return
}
return f.Close()
} |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Nim | Nim | import strutils
import bitmap
import streams
type FormatError = object of CatchableError
# States used to parse the header.
type State = enum waitingMagic, waitingWidth, waitingHeight, waitingColors
#---------------------------------------------------------------------------------------------------
iterator tokens(f: Stream): tuple[value: string, lastInLine: bool] =
## Yield the tokens in the header.
for line in f.lines:
if not line.startsWith('#'):
let fields = line.splitWhitespace()
for i, t in fields:
yield (t, i == fields.high)
#---------------------------------------------------------------------------------------------------
proc getInt(s: string): int {.inline.} =
## Try to parse an int. Raise an exception if not an integer.
try:
result = s.parseInt()
except ValueError:
raise newException(FormatError, "Invalid value")
#---------------------------------------------------------------------------------------------------
proc header(f: Stream): tuple[width, height: Index] =
## Read the header and retrun the image width and height.
var state = waitingMagic
for (token, lastInLine) in f.tokens:
case state
of waitingMagic:
if token != "P6":
raise newException(FormatError, "Invalid file header")
of waitingWidth:
result.width = token.getInt()
of waitingHeight:
result.height = token.getInt()
of waitingColors:
if token.getInt() != 255:
raise newException(FormatError, "Invalid number of colors")
if not lastInLine:
raise newException(FormatError, "Invalid data after number of colors")
break
state = succ(state)
#---------------------------------------------------------------------------------------------------
proc readPPM*(f: Stream): Image =
## Read a PPM file from a stream into an image.
let header = f.header()
result = newImage(header.width, header.height)
var
arr: array[256, int8]
read = f.readData(addr(arr), 256)
pos = 0
while read != 0:
for i in 0 ..< read:
case pos mod 3
of 0: result.pixels[pos div 3].r = arr[i].uint8
of 1: result.pixels[pos div 3].g = arr[i].uint8
of 2: result.pixels[pos div 3].b = arr[i].uint8
else: discard
inc pos
read = f.readData(addr(arr), 256)
if pos != 3 * result.w * result.h:
raise newException(FormatError, "Truncated file")
#---------------------------------------------------------------------------------------------------
proc readPPM*(filename: string): Image =
## Load a PPM file into an image.
var file = openFileStream(filename, fmRead)
result = file.readPPM()
file.close()
#———————————————————————————————————————————————————————————————————————————————————————————————————
when isMainModule:
let image = readPPM("output.ppm")
echo image.h, " ", image.w |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #OCaml | OCaml | let read_ppm ~filename =
let ic = open_in filename in
let line = input_line ic in
if line <> "P6" then invalid_arg "not a P6 ppm file";
let line = input_line ic in
let line =
try if line.[0] = '#' (* skip comments *)
then input_line ic
else line
with _ -> line
in
let width, height =
Scanf.sscanf line "%d %d" (fun w h -> (w, h))
in
let line = input_line ic in
if line <> "255" then invalid_arg "not a 8 bit depth image";
let all_channels =
let kind = Bigarray.int8_unsigned
and layout = Bigarray.c_layout
in
Bigarray.Array3.create kind layout 3 width height
in
let r_channel = Bigarray.Array3.slice_left_2 all_channels 0
and g_channel = Bigarray.Array3.slice_left_2 all_channels 1
and b_channel = Bigarray.Array3.slice_left_2 all_channels 2
in
for y = 0 to pred height do
for x = 0 to pred width do
r_channel.{x,y} <- (input_byte ic);
g_channel.{x,y} <- (input_byte ic);
b_channel.{x,y} <- (input_byte ic);
done;
done;
close_in ic;
(all_channels,
r_channel,
g_channel,
b_channel) |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #ACL2 | ACL2 | PROC Test(BYTE v)
PrintF("Variable v has value %B%E",v)
IF v THEN
PrintE("Condition IF v is satisfied.")
ELSE
PrintE("Condition IF v is not satisfied.")
FI
IF v=0 THEN
PrintE("Condition IF v=0 is satisfied.")
ELSE
PrintE("Condition IF v=0 is not satisfied.")
FI
IF v<>0 THEN
PrintE("Condition IF v<>0 is satisfied.")
ELSE
PrintE("Condition IF v<>0 is not satisfied.")
FI
IF v#0 THEN
PrintE("Condition IF v#0 is satisfied.")
ELSE
PrintE("Condition IF v#0 is not satisfied.")
FI
PutE()
RETURN
PROC Main()
Test(0)
Test(1)
Test(86)
RETURN |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #Action.21 | Action! | PROC Test(BYTE v)
PrintF("Variable v has value %B%E",v)
IF v THEN
PrintE("Condition IF v is satisfied.")
ELSE
PrintE("Condition IF v is not satisfied.")
FI
IF v=0 THEN
PrintE("Condition IF v=0 is satisfied.")
ELSE
PrintE("Condition IF v=0 is not satisfied.")
FI
IF v<>0 THEN
PrintE("Condition IF v<>0 is satisfied.")
ELSE
PrintE("Condition IF v<>0 is not satisfied.")
FI
IF v#0 THEN
PrintE("Condition IF v#0 is satisfied.")
ELSE
PrintE("Condition IF v#0 is not satisfied.")
FI
PutE()
RETURN
PROC Main()
Test(0)
Test(1)
Test(86)
RETURN |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Ring | Ring |
# Project : Caesar cipher
cipher = "pack my box with five dozen liquor jugs"
abc = "abcdefghijklmnopqrstuvwxyz"
see "text is to be encrypted:" + nl
see cipher+ nl + nl
str = ""
key = random(24) + 1
see "key = " + key + nl + nl
see "encrypted:" + nl
caesarencode(cipher, key)
see str + nl + nl
cipher = str
see "decrypted again:" + nl
caesardecode(cipher, key)
see str + nl
func caesarencode(cipher, key)
str = ""
for n = 1 to len(cipher)
if cipher[n] != " "
pos = substr(abc, cipher[n])
if pos + key < len(abc)
str = str + abc[pos + key]
else
if (pos+key)-len(abc) != 0
str = str + abc[(pos+key)%len(abc)]
else
str = str +abc[key+pos]
ok
ok
else
str = str + " "
ok
next
return str
func caesardecode(cipher, key)
str = ""
for n= 1 to len(cipher)
if cipher[n] != " "
pos = substr(abc, cipher[n])
if (pos - key) > 0 and pos != key
str = str + abc[pos - key]
loop
else
if pos = key
str = str + char(122)
else
str = str + abc[len(abc)-(key-pos)]
ok
ok
else
str = str + " "
ok
next
return str
|
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Haskell | Haskell | import Data.List
import Data.Char
import Control.Monad
import Control.Arrow
import System.Environment
int2bin :: Int -> [Int]
int2bin = unfoldr(\x -> if x==0 then Nothing
else Just (uncurry(flip(,)) (divMod x 2)))
bin2int :: [Int] -> Int
bin2int = foldr ((.(2 *)).(+)) 0
bitReader = map (chr.bin2int). takeWhile(not.null). unfoldr(Just. splitAt 7)
. (take =<< (7 *) . (`div` 7) . length)
bitWriter xs = tt ++ z00 where
tt = concatMap (take 7.(++repeat 0).int2bin.ord) xs
z00 = replicate (length xs `mod` 8) 0
main = do
(xs:_) <- getArgs
let bits = bitWriter xs
putStrLn "Text to compress:"
putStrLn $ '\t' : xs
putStrLn $ "Uncompressed text length is " ++ show (length xs)
putStrLn $ "Compressed text has " ++ show (length bits `div` 8) ++ " bytes."
putStrLn "Read and decompress:"
putStrLn $ '\t' : bitReader bits |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Haskell | Haskell | {-# LANGUAGE ScopedTypeVariables #-}
module Bitmap.Netpbm(readNetpbm, writeNetpbm) where
import Bitmap
import Data.Char
import System.IO
import Control.Monad
import Control.Monad.ST
import Data.Array.ST
nil :: a
nil = undefined
readNetpbm :: forall c. Color c => FilePath -> IO (Image RealWorld c)
readNetpbm path = do
let die = fail "readNetpbm: bad format"
ppm <- readFile path
let (s, rest) = splitAt 2 ppm
unless (s == magicNumber) die
let getNum :: String -> IO (Int, String)
getNum ppm = do
let (s, rest) = span isDigit $ skipBlanks ppm
when (null s) die
return (read s, rest)
(width, rest) <- getNum rest
(height, rest) <- getNum rest
(_, c : rest) <-
if getMaxval then getNum rest else return (nil, rest)
unless (isSpace c) die
i <- stToIO $ listImage width height $
fromNetpbm $ map fromEnum rest
return i
where skipBlanks =
dropWhile isSpace .
until ((/= '#') . head) (tail . dropWhile (/= '\n')) .
dropWhile isSpace
magicNumber = netpbmMagicNumber (nil :: c)
getMaxval = not $ null $ netpbmMaxval (nil :: c)
writeNetpbm :: forall c. Color c => FilePath -> Image RealWorld c -> IO ()
writeNetpbm path i = withFile path WriteMode $ \h -> do
(width, height) <- stToIO $ dimensions i
let w = hPutStrLn h
w $ magicNumber
w $ show width ++ " " ++ show height
unless (null maxval) (w maxval)
stToIO (getPixels i) >>= hPutStr h . toNetpbm
where magicNumber = netpbmMagicNumber (nil :: c)
maxval = netpbmMaxval (nil :: c) |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Oz | Oz | functor
import
Bitmap
Open
export
Read
%% Write
define
fun {Read Filename}
F = {New Open.file init(name:Filename)}
fun {ReadColor8 _}
Bytes = {F read(list:$ size:3)}
in
{List.toTuple color Bytes}
end
fun {ReadColor16 _}
Bytes = {F read(list:$ size:6)}
in
{List.toTuple color {Map {PairUp Bytes} FromBytes}}
end
in
try
Magic = {F read(size:2 list:$)}
if Magic \= "P6" then raise bitmapIO(read unsupportedFormat(Magic)) end end
Width = {ReadNumber F}
Height = {ReadNumber F}
MaxVal = {ReadNumber F}
MaxVal =< 0xffff = true
Reader = if MaxVal =< 0xff then ReadColor8 else ReadColor16 end
B = {Bitmap.new Width Height}
in
{Bitmap.transform B Reader}
B
finally
{F close}
end
end
fun {ReadNumber F}
Ds
in
{SkipWS F}
Ds = for collect:Collect break:Break do
[C] = {F read(list:$ size:1)}
in
if {Char.isDigit C} then {Collect C}
else {Break}
end
end
{SkipWS F}
{String.toInt Ds}
end
proc {SkipWS F}
[C] = {F read(list:$ size:1)}
in
if {Char.isSpace C} then {SkipWS F}
elseif C == &# then
{SkipLine F}
else
{F seek(whence:current offset:~1)}
end
end
proc {SkipLine F}
[C] = {F read(list:$ size:1)}
in
if C \= &\n andthen C \= &\r then {SkipLine F} end
end
fun {PairUp Xs}
case Xs of X1|X2|Xr then [X1 X2]|{PairUp Xr}
[] nil then nil
end
end
fun {FromBytes [C1 C2]}
C1 * 0x100 + C2
end
%% Omitted: Write
end |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #Ada | Ada | type Boolean is (False, True); |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #ALGOL_68 | ALGOL 68 | BOOL f = FALSE, t = TRUE;
[]BOOL ft = (f, t);
STRING or = " or ";
FOR key TO UPB ft DO
BOOL val = ft[key];
UNION(VOID, INT) void = (val|666|EMPTY);
REF STRING ref = (val|HEAP STRING|NIL);
INT int = ABS val;
REAL real = ABS val;
COMPL compl = ABS val;
BITS bits = BIN ABS val; # or bitspack(val); #
BYTES bytes = bytes pack((val|"?"|null char)*bytes width);
CHAR char = (val|"?"|null char);
STRING string = (val|"?"|"");
print((((val | "TRUE" | "FALSE" ), ": ", val, or, (val|flip|flop), new line)));
print((" void: ", " => ", (void|(VOID):FALSE|TRUE), new line));
print((" ref: ", " => ", ref ISNT REF STRING(NIL), new line));
print((" int: ", int , " => ", int /= 0, new line));
print((" real: ", real , " => ", real /= 0, new line));
print((" compl: ", compl , " => ", compl /= 0, new line));
print((" bits: ", bits , " => ", ABS bits /= 0, or, bits /= 2r0, or,
bits width ELEM bits, or, []BOOL(bits)[bits width], new line));
print((" bytes: """, STRING(bytes) , """ => ", 1 ELEM bytes /= null char, or,
STRING(bytes) /= null char*bytes width, or,
STRING(bytes)[1] /= null char, new line));
print((" char: """, char , """ => ", ABS char /= 0 , or, char /= null char, new line));
print(("string: """, string , """ => ", string /= "", or, UPB string /= 0, new line));
print((new line))
OD |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Ruby | Ruby | class String
ALFABET = ("A".."Z").to_a
def caesar_cipher(num)
self.tr(ALFABET.join, ALFABET.rotate(num).join)
end
end
#demo:
encypted = "THEYBROKEOURCIPHEREVERYONECANREADTHIS".caesar_cipher(3)
decrypted = encypted.caesar_cipher(-3)
|
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #J | J | bitReader =: a. {~ _7 #.\ ({.~ <.&.(%&7)@#)
bitWriter =: , @ ((7$2) & #: @ (a.&i.)), 0 $~ 8 | # |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Julia | Julia |
function compress7(inio, outio)
nextwritebyte = read(inio, UInt8) & 0x7f
filled = 7
while !eof(inio)
inbyte = read(inio, UInt8)
write(outio, UInt8(nextwritebyte | inbyte << filled))
nextwritebyte = inbyte >> (8 - filled)
filled = (filled + 7) % 8
if filled == 0
if eof(inio)
break
end
nextwritebyte = read(inio, UInt8) & 0x7f
filled = 7
end
end
if filled != 0
write(outio, UInt8(nextwritebyte))
end
end
function expand7(inio, outio)
newbyte = read(inio, UInt8)
write(outio, UInt8(newbyte & 0x7f))
residualbyte::UInt8 = newbyte >> 7
filled = 1
while !eof(inio)
inbyte = read(inio, UInt8)
write(outio, UInt8((residualbyte | inbyte << filled) & 0x7f))
residualbyte = inbyte >> (7 - filled)
filled = (filled + 1) % 7
if filled == 0
write(outio, UInt8(residualbyte & 0x7f))
residualbyte = 0
end
end
end
str = b"These bit oriented I/O functions can be used to implement compressors and decompressors."
ins = IOBuffer(str)
outs = IOBuffer()
newouts = IOBuffer()
compress7(ins, outs)
seek(outs,0)
expand7(outs, newouts)
println("Initial string of length $(length(str)): ", String(ins.data))
println("Compressed to length $(length(outs.data)) on line below:\n", String(outs.data))
println("Decompressed string: ", String(newouts.data))
|
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #J | J | require 'files'
NB. ($x) is height, width, colors per pixel
writeppm=:dyad define
header=. 'P6',LF,(":1 0{$x),LF,'255',LF
(header,,x{a.) fwrite y
) |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Java | Java | import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.charset.StandardCharsets;
public class PPMWriter {
public void bitmapToPPM(File file, BasicBitmapStorage bitmap) throws IOException {
file.delete();
try (var os = new FileOutputStream(file, true);
var bw = new BufferedOutputStream(os)) {
var header = String.format("P6\n%d %d\n255\n",
bitmap.getWidth(), bitmap.getHeight());
bw.write(header.getBytes(StandardCharsets.US_ASCII));
for (var y = 0; y < bitmap.getHeight(); y++) {
for (var x = 0; x < bitmap.getWidth(); x++) {
var pixel = bitmap.getPixel(x, y);
bw.write(pixel.getRed());
bw.write(pixel.getGreen());
bw.write(pixel.getBlue());
}
}
}
}
} |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Perl | Perl | #! /usr/bin/perl
use strict;
use Image::Imlib2;
my $img = Image::Imlib2->load("out0.ppm");
# let's do something with it now
$img->set_color(255, 255, 255, 255);
$img->draw_line(0,0, $img->width,$img->height);
$img->image_set_format("png");
$img->save("out1.png");
exit 0; |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #ALGOL_W | ALGOL W |
1 ^ 1
1
1 ^ 0
0
|
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #APL | APL |
1 ^ 1
1
1 ^ 0
0
|
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Run_BASIC | Run BASIC | input "Gimme a ofset:";ofst ' set any offset you like
a$ = "Pack my box with five dozen liquor jugs"
print " Original: ";a$
a$ = cipher$(a$,ofst)
print "Encrypted: ";a$
print "Decrypted: ";cipher$(a$,ofst+6)
FUNCTION cipher$(a$,ofst)
for i = 1 to len(a$)
aa$ = mid$(a$,i,1)
code$ = " "
if aa$ <> " " then
ua$ = upper$(aa$)
a = asc(ua$) - 64
code$ = chr$((((a mod 26) + ofst) mod 26) + 65)
if ua$ <> aa$ then code$ = lower$(code$)
end if
cipher$ = cipher$;code$
next i
END FUNCTION |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Kotlin | Kotlin | // version 1.2.31
import java.io.File
class BitFilter(val f: File, var accu: Int = 0, var bits: Int = 0) {
private val bw = f.bufferedWriter()
private val br = f.bufferedReader()
fun write(buf: ByteArray, start: Int, _nBits: Int, _shift: Int) {
var nBits = _nBits
var index = start + _shift / 8
var shift = _shift % 8
while (nBits != 0 || bits >= 8) {
while (bits >= 8) {
bits -= 8
bw.write(accu ushr bits)
accu = accu and ((1 shl bits) - 1)
}
while (bits < 8 && nBits != 0) {
val b = buf[index].toInt()
accu = (accu shl 1) or (((128 ushr shift) and b) ushr (7 - shift))
nBits--
bits++
if (++shift == 8) { shift = 0; index++ }
}
}
}
fun read(buf: ByteArray, start: Int, _nBits: Int, _shift: Int) {
var nBits = _nBits
var index = start + _shift / 8
var shift = _shift % 8
while (nBits != 0) {
while (bits != 0 && nBits != 0) {
val mask = 128 ushr shift
if ((accu and (1 shl (bits - 1))) != 0)
buf[index] = (buf[index].toInt() or mask).toByte()
else
buf[index] = (buf[index].toInt() and mask.inv()).toByte()
nBits--
bits--
if (++shift >= 8) { shift = 0; index++ }
}
if (nBits == 0) break
accu = (accu shl 8) or br.read()
bits += 8
}
}
fun closeWriter() {
if (bits != 0) {
accu = (accu shl (8 - bits))
bw.write(accu)
}
bw.close()
accu = 0
bits = 0
}
fun closeReader() {
br.close()
accu = 0
bits = 0
}
}
fun main(args: Array<String>) {
val s = "abcdefghijk".toByteArray(Charsets.UTF_8)
val f = File("test.bin")
val bf = BitFilter(f)
/* for each byte in s, write 7 bits skipping 1 */
for (i in 0 until s.size) bf.write(s, i, 7, 1)
bf.closeWriter()
/* read 7 bits and expand to each byte of s2 skipping 1 bit */
val s2 = ByteArray(s.size)
for (i in 0 until s2.size) bf.read(s2, i, 7, 1)
bf.closeReader()
println(String(s2, Charsets.UTF_8))
} |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Julia | Julia | using Images, FileIO
h, w = 50, 70
img = zeros(RGB{N0f8}, h, w)
img[10:40, 5:35] = colorant"skyblue"
for i in 26:50, j in (i-25):40
img[i, j] = colorant"sienna1"
end
save("data/bitmapWrite.ppm", img)
save("data/bitmapWrite.png", img) |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Kotlin | Kotlin | // Version 1.2.40
import java.awt.Color
import java.awt.Graphics
import java.awt.image.BufferedImage
import java.io.FileOutputStream
class BasicBitmapStorage(width: Int, height: Int) {
val image = BufferedImage(width, height, BufferedImage.TYPE_3BYTE_BGR)
fun fill(c: Color) {
val g = image.graphics
g.color = c
g.fillRect(0, 0, image.width, image.height)
}
fun setPixel(x: Int, y: Int, c: Color) = image.setRGB(x, y, c.getRGB())
fun getPixel(x: Int, y: Int) = Color(image.getRGB(x, y))
}
fun main(args: Array<String>) {
// create BasicBitmapStorage object
val width = 640
val height = 640
val bbs = BasicBitmapStorage(width, height)
for (y in 0 until height) {
for (x in 0 until width) {
val c = Color(x % 256, y % 256, (x * y) % 256)
bbs.setPixel(x, y, c)
}
}
// now write it to a PPM file
val fos = FileOutputStream("output.ppm")
val buffer = ByteArray(width * 3) // write one line at a time
fos.use {
val header = "P6\n$width $height\n255\n".toByteArray()
with (it) {
write(header)
for (y in 0 until height) {
for (x in 0 until width) {
val c = bbs.getPixel(x, y)
buffer[x * 3] = c.red.toByte()
buffer[x * 3 + 1] = c.green.toByte()
buffer[x * 3 + 2] = c.blue.toByte()
}
write(buffer)
}
}
}
} |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Phix | Phix | -- demo\rosetta\Bitmap_read_ppm.exw (runnable version)
function read_ppm(string filename)
sequence image, line
integer dimx, dimy, maxcolor
atom fn = open(filename, "rb")
if fn<0 then
return -1 -- unable to open
end if
line = gets(fn)
if line!="P6\n" then
return -1 -- only ppm6 files are supported
end if
line = gets(fn)
{{dimx,dimy}} = scanf(line,"%d %d%s")
line = gets(fn)
{{maxcolor}} = scanf(line,"%d%s")
image = repeat(repeat(0,dimy),dimx)
for y=1 to dimy do
for x=1 to dimx do
image[x][y] = getc(fn)*#10000 + getc(fn)*#100 + getc(fn)
end for
end for
close(fn)
return image
end function
--include ppm.e -- read_ppm(), write_ppm(), to_grey() (as distributed, instead of the above)
sequence img = read_ppm("Lena.ppm")
img = to_grey(img)
write_ppm("LenaGray.ppm",img) |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #PicoLisp | PicoLisp | (de ppmRead (File)
(in File
(unless (and `(hex "5036") (rd 2)) # P6
(quit "Wrong file format" File) )
(rd 1)
(let (DX 0 DY 0 Max 0 C)
(while (>= 9 (setq C (- (rd 1) `(char "0"))) 0)
(setq DX (+ (* 10 DX) C)) )
(while (>= 9 (setq C (- (rd 1) `(char "0"))) 0)
(setq DY (+ (* 10 DY) C)) )
(while (>= 9 (setq C (- (rd 1) `(char "0"))) 0)
(setq Max (+ (* 10 Max) C)) )
(prog1
(make (do DY (link (need DX))))
(for Y @
(map
'((X) (set X (list (rd 1) (rd 1) (rd 1))))
Y ) ) ) ) ) ) |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #AppleScript | AppleScript | 1 > 2 --> false
not false --> true
{true as integer, false as integer, 1 as boolean, 0 as boolean}
--> {1, 0, true, false}
true = 1 --> false |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #ARM_Assembly | ARM Assembly |
/* ARM assembly Raspberry PI */
/* program areaString.s */
/* Constantes */
@ The are no TRUE or FALSE constants in ARM Assembly
.equ FALSE, 0 @ or other value
.equ TRUE, 1 @ or other value
.equ STDOUT, 1 @ Linux output console
.equ EXIT, 1 @ Linux syscall
.equ WRITE, 4 @ Linux syscall
/* Initialized data */
.data
szMessTrue: .asciz "The value is true.\n"
szMessFalse: .asciz "The value is false.\n"
/* UnInitialized data */
.bss
/* code section */
.text
.global main
main: /* entry of program */
push {fp,lr} /* saves 2 registers */
mov r0,#0
//mov r0,#1 @uncomment pour other test
cmp r0,#TRUE
bne 1f
@ value true
ldr r0,iAdrszMessTrue
bl affichageMess
b 100f
1: @ value False
ldr r0,iAdrszMessFalse
bl affichageMess
100: /* standard end of the program */
mov r0, #0 @ return code
pop {fp,lr} @restaur 2 registers
mov r7, #EXIT @ request to exit program
swi 0 @ perform the system call
iAdrszMessTrue: .int szMessTrue
iAdrszMessFalse: .int szMessFalse
/******************************************************************/
/* display text with size calculation */
/******************************************************************/
/* r0 contains the address of the message */
affichageMess:
push {fp,lr} /* save registres */
push {r0,r1,r2,r7} /* save others registers */
mov r2,#0 /* counter length */
1: /* loop length calculation */
ldrb r1,[r0,r2] /* read octet start position + index */
cmp r1,#0 /* if 0 its over */
addne r2,r2,#1 /* else add 1 in the length */
bne 1b /* and loop */
/* so here r2 contains the length of the message */
mov r1,r0 /* address message in r1 */
mov r0,#STDOUT /* code to write to the standard output Linux */
mov r7, #WRITE /* code call system "write" */
swi #0 /* call systeme */
pop {r0,r1,r2,r7} /* restaur others registers */
pop {fp,lr} /* restaur des 2 registres */
bx lr /* return */
|
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Rust | Rust | use std::io::{self, Write};
use std::fmt::Display;
use std::{env, process};
fn main() {
let shift: u8 = env::args().nth(1)
.unwrap_or_else(|| exit_err("No shift provided", 2))
.parse()
.unwrap_or_else(|e| exit_err(e, 3));
let plain = get_input()
.unwrap_or_else(|e| exit_err(&e, e.raw_os_error().unwrap_or(-1)));
let cipher = plain.chars()
.map(|c| {
let case = if c.is_uppercase() {'A'} else {'a'} as u8;
if c.is_alphabetic() { (((c as u8 - case + shift) % 26) + case) as char } else { c }
}).collect::<String>();
println!("Cipher text: {}", cipher.trim());
}
fn get_input() -> io::Result<String> {
print!("Plain text: ");
try!(io::stdout().flush());
let mut buf = String::new();
try!(io::stdin().read_line(&mut buf));
Ok(buf)
}
fn exit_err<T: Display>(msg: T, code: i32) -> ! {
let _ = writeln!(&mut io::stderr(), "ERROR: {}", msg);
process::exit(code);
} |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Lingo | Lingo | -- parent script "BitArray"
property ancestor
property bitSize
property _pow2
----------------------------------------
-- @constructor
-- @param {integer} [bSize=0]
----------------------------------------
on new (me, bSize)
if voidP(bitSize) then bitSize=0
me.bitSize = bSize
byteSize = bitSize/8 + (bitSize mod 8>0)
me._pow2 = [128,64,32,16,8,4,2,1] -- pow2 lookup list
me.ancestor = ByteArray(byteSize)
return me
end
----------------------------------------
-- Sets bit at position <bitPos> to <bitValue>.
-- @param {integer} bitPos - starts at 1, as ByteArray's native byte access functions
-- @param {boolean} bitValue
----------------------------------------
on setBit (me, bitPos, bitValue)
bytePos = (bitPos-1)/8 + 1
bitPos = (bitPos-1) mod 8 + 1
if bitValue then
me[bytePos] = bitOr(me[bytePos], me._pow2[bitPos])
else
me[bytePos] = bitAnd(me[bytePos], bitNot(me._pow2[bitPos]))
end if
end
----------------------------------------
-- Gets bit value at position <bitPos>.
-- @param {integer} bitPos - starts at 1, as ByteArray's native byte access functions
-- @return {boolean} bitValue
----------------------------------------
on getBit (me, bitPos)
bytePos = (bitPos-1)/8 + 1
bitPos = (bitPos-1) mod 8 + 1
return bitAnd(me[bytePos], me._pow2[bitPos])<>0
end
----------------------------------------
-- Returns all bits as string. To be in accordance with ByteArray's native toHexString(),
-- returned string is separated with SPACE (e.g. "0 1 1 0...")
-- @param {integer} [bitSizeOnly=FALSE] - if TRUE, only <bitSize> bits without byte-padding
-- @return {string}
----------------------------------------
on toBinString (me, bitSizeOnly)
res = ""
repeat with i = 1 to me.length
byte = me[i]
repeat with j = 1 to 8
put (bitAnd(byte, me._pow2[j])<>0)&" " after res
if bitSizeOnly and (i-1)*8+j=me.bitSize then exit repeat
end repeat
end repeat
delete the last char of res
return res
end |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Lua | Lua | local function BitWriter() return {
accumulator = 0, -- For current byte.
bitCount = 0, -- Bits set in current byte.
outChars = {},
-- writer:writeBit( bit )
writeBit = function(writer, bit)
writer.bitCount = writer.bitCount + 1
if bit > 0 then
writer.accumulator = writer.accumulator + 2^(8-writer.bitCount)
end
if writer.bitCount == 8 then
writer:_flush()
end
end,
-- writer:writeLsb( value, width )
writeLsb = function(writer, value, width)
for i = 1, width do
writer:writeBit(value%2)
value = math.floor(value/2)
end
end,
-- dataString = writer:getOutput( )
getOutput = function(writer)
writer:_flush()
return table.concat(writer.outChars)
end,
_flush = function(writer)
if writer.bitCount == 0 then return end
table.insert(writer.outChars, string.char(writer.accumulator))
writer.accumulator = 0
writer.bitCount = 0
end,
} end
local function BitReader(data) return {
bitPosition = 0, -- Absolute position in 'data'.
-- bit = reader:readBit( ) -- Returns nil at end-of-data.
readBit = function(reader)
reader.bitPosition = reader.bitPosition + 1
local bytePosition = math.floor((reader.bitPosition-1)/8) + 1
local byte = data:byte(bytePosition)
if not byte then return nil end
local bitIndex = ((reader.bitPosition-1)%8) + 1
return math.floor(byte / 2^(8-bitIndex)) % 2
end,
-- value = reader:readLsb( width ) -- Returns nil at end-of-data.
readLsb = function(reader, width)
local accumulator = 0
for i = 1, width do
local bit = reader:readBit()
if not bit then return nil end
if bit > 0 then
accumulator = accumulator + 2^(i-1)
end
end
return accumulator
end,
} end |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Lua | Lua |
-- helper function, simulates PHP's array_fill function
local array_fill = function(vbegin, vend, value)
local t = {}
for i=vbegin, vend do
t[i] = value
end
return t
end
Bitmap = {}
Bitmap.__index = Bitmap
function Bitmap.new(width, height)
local self = {}
setmetatable(self, Bitmap)
local white = array_fill(0, width, {255, 255, 255})
self.data = array_fill(0, height, white)
self.width = width
self.height = height
return self
end
function Bitmap:writeRawPixel(file, c)
local dt
dt = string.format("%c", c)
file:write(dt)
end
function Bitmap:writeComment(fh, ...)
local strings = {...}
local str = ""
local result
for _, s in pairs(strings) do
str = str .. tostring(s)
end
result = string.format("# %s\n", str)
fh:write(result)
end
function Bitmap:writeP6(filename)
local fh = io.open(filename, 'w')
if not fh then
error(string.format("failed to open %q for writing", filename))
else
fh:write(string.format("P6 %d %d 255\n", self.width, self.height))
self:writeComment(fh, "automatically generated at ", os.date())
for _, row in pairs(self.data) do
for _, pixel in pairs(row) do
self:writeRawPixel(fh, pixel[1])
self:writeRawPixel(fh, pixel[2])
self:writeRawPixel(fh, pixel[3])
end
end
end
end
function Bitmap:fill(x, y, width, height, color)
width = (width == nil) and self.width or width
height = (height == nil) and self.height or height
width = width + x
height = height + y
for i=y, height do
for j=x, width do
self:setPixel(j, i, color)
end
end
end
function Bitmap:setPixel(x, y, color)
if x >= self.width then
--error("x is bigger than self.width!")
return false
elseif x < 0 then
--error("x is smaller than 0!")
return false
elseif y >= self.height then
--error("y is bigger than self.height!")
return false
elseif y < 0 then
--error("y is smaller than 0!")
return false
end
self.data[y][x] = color
return true
end
function example_colorful_stripes()
local w = 260*2
local h = 260*2
local b = Bitmap.new(w, h)
--b:fill(2, 2, 18, 18, {240,240,240})
b:setPixel(0, 15, {255,68,0})
for i=1, w do
for j=1, h do
b:setPixel(i, j, {
(i + j * 8) % 256,
(j + (255 * i)) % 256,
(i * j) % 256
}
);
end
end
return b
end
example_colorful_stripes():writeP6('p6.ppm')
|
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #PL.2FI | PL/I |
/* BITMAP FILE: read in a file in PPM format, P6 (binary). 14/5/2010 */
test: procedure options (main);
declare (m, n, max_color, i, j) fixed binary (31);
declare ch character (1), ID character (2);
declare 1 pixel union,
2 color bit(24) aligned,
2 primary_colors,
3 R char (1),
3 G char (1),
3 B char (1);
declare in file record;
open file (in) title ('/IMAGE.PPM,TYPE(FIXED),RECSIZE(1)' ) input;
call get_char;
ID = ch;
call get_char;
substr(ID, 2,1) = ch;
/* Read in the dimensions of the image */
call get_integer (m);
call get_integer (n);
/* Read in the maximum color size used */
call get_integer (max_color);
/* The previous call reads in ONE line feed or CR or other terminator */
/* character. */
begin;
declare image (0:m-1,0:n-1) bit (24);
do i = 0 to hbound(image, 1);
do j = 0 to hbound(image,2);
read file (in) into (R);
read file (in) into (G);
read file (in) into (B);
image(i,j) = color;
end;
end;
end;
get_char: procedure;
do until (ch ^= ' ');
read file (in) into (ch);
end;
end get_char;
get_integer: procedure (value);
declare value fixed binary (31);
do until (ch = ' ');
read file (in) into (ch);
end;
value = 0;
do until (is_digit(ch));
value = value*10 + ch;
read file (in) into (ch);
end;
end get_integer;
is_digit: procedure (ch) returns (bit(1));
declare ch character (1);
return (index('0123456789', ch) > 0);
end is_digit;
end test; |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #Arturo | Arturo | a: true
b: false
if? a [ print "yep" ] else [ print "nope" ]
if? b -> print "nope"
else -> print "yep" |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Scala | Scala | object Caesar {
private val alphaU='A' to 'Z'
private val alphaL='a' to 'z'
def encode(text:String, key:Int)=text.map{
case c if alphaU.contains(c) => rot(alphaU, c, key)
case c if alphaL.contains(c) => rot(alphaL, c, key)
case c => c
}
def decode(text:String, key:Int)=encode(text,-key)
private def rot(a:IndexedSeq[Char], c:Char, key:Int)=a((c-a.head+key+a.size)%a.size)
} |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #MIPS_Assembly | MIPS Assembly | type
BitWriter * = tuple
file: File
bits: uint8
nRemain: int
BitReader * = tuple
file: File
bits: uint8
nRemain: int
nRead: int
proc newBitWriter * (file: File) : ref BitWriter =
result = new BitWriter
result.file = file
result.bits = 0
result.nRemain = 8
proc flushBits (stream : ref BitWriter) =
discard stream.file.writeBuffer(stream.bits.addr, 1)
stream.nRemain = 8
stream.bits = 0
proc write * (stream: ref BitWriter, bits: uint8, nBits: int) =
assert(nBits <= 8)
for ii in countdown((nBits - 1), 0) :
stream.bits = (stream.bits shl 1) or ((bits shr ii) and 1)
stream.nRemain.dec(1)
if stream.nRemain == 0:
stream.flushBits
proc flush * (stream: ref BitWriter) =
if stream.nRemain < 8:
stream.bits = stream.bits shl stream.nRemain
stream.flushBits
proc newBitReader * (file: File) : ref BitReader =
result = new BitReader
result.file = file
result.bits = 0
result.nRemain = 0
result.nRead = 0
proc read * (stream: ref BitReader, nBits: int) : uint8 =
assert(nBits <= 8)
result = 0
for ii in 0 ..< nBits :
if stream.nRemain == 0:
stream.nRead = stream.file.readBuffer(stream.bits.addr, 1)
if stream.nRead == 0:
break
stream.nRemain = 8
result = (result shl 1) or ((stream.bits shr 7) and 1)
stream.bits = stream.bits shl 1
stream.nRemain.dec(1)
when isMainModule:
var
file: File
writer: ref BitWriter
reader: ref BitReader
file = open("testfile.dat", fmWrite)
writer = newBitWriter(file)
for ii in 0 .. 255:
writer.write(ii.uint8, 7)
writer.flush
file.close
var dataCtr = 0
file = open("testfile.dat", fmRead)
reader = newBitReader(file)
while true:
let aByte = reader.read(7)
if reader.nRead == 0:
break
assert((dataCtr and 0x7f).uint8 == aByte)
inc dataCtr
assert(dataCtr == 256)
file.close
echo "OK" |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Nim | Nim | type
BitWriter * = tuple
file: File
bits: uint8
nRemain: int
BitReader * = tuple
file: File
bits: uint8
nRemain: int
nRead: int
proc newBitWriter * (file: File) : ref BitWriter =
result = new BitWriter
result.file = file
result.bits = 0
result.nRemain = 8
proc flushBits (stream : ref BitWriter) =
discard stream.file.writeBuffer(stream.bits.addr, 1)
stream.nRemain = 8
stream.bits = 0
proc write * (stream: ref BitWriter, bits: uint8, nBits: int) =
assert(nBits <= 8)
for ii in countdown((nBits - 1), 0) :
stream.bits = (stream.bits shl 1) or ((bits shr ii) and 1)
stream.nRemain.dec(1)
if stream.nRemain == 0:
stream.flushBits
proc flush * (stream: ref BitWriter) =
if stream.nRemain < 8:
stream.bits = stream.bits shl stream.nRemain
stream.flushBits
proc newBitReader * (file: File) : ref BitReader =
result = new BitReader
result.file = file
result.bits = 0
result.nRemain = 0
result.nRead = 0
proc read * (stream: ref BitReader, nBits: int) : uint8 =
assert(nBits <= 8)
result = 0
for ii in 0 ..< nBits :
if stream.nRemain == 0:
stream.nRead = stream.file.readBuffer(stream.bits.addr, 1)
if stream.nRead == 0:
break
stream.nRemain = 8
result = (result shl 1) or ((stream.bits shr 7) and 1)
stream.bits = stream.bits shl 1
stream.nRemain.dec(1)
when isMainModule:
var
file: File
writer: ref BitWriter
reader: ref BitReader
file = open("testfile.dat", fmWrite)
writer = newBitWriter(file)
for ii in 0 .. 255:
writer.write(ii.uint8, 7)
writer.flush
file.close
var dataCtr = 0
file = open("testfile.dat", fmRead)
reader = newBitReader(file)
while true:
let aByte = reader.read(7)
if reader.nRead == 0:
break
assert((dataCtr and 0x7f).uint8 == aByte)
inc dataCtr
assert(dataCtr == 256)
file.close
echo "OK" |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #LiveCode | LiveCode |
export image "test" to file "~/Test.PPM" as paint -- paint format is one of PBM, PGM, or PPM
|
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #M2000_Interpreter | M2000 Interpreter |
Module Checkit {
Function Bitmap (x as long, y as long) {
if x<1 or y<1 then Error "Wrong dimensions"
structure rgb {
red as byte
green as byte
blue as byte
}
m=len(rgb)*x mod 4
if m>0 then m=4-m ' add some bytes to raster line
m+=len(rgb) *x
Structure rasterline {
{
pad as byte*m
}
\\ union pad+hline
hline as rgb*x
}
Structure Raster {
magic as integer*4
w as integer*4
h as integer*4
lines as rasterline*y
}
Buffer Clear Image1 as Raster
\\ 24 chars as header to be used from bitmap render build in functions
Return Image1, 0!magic:="cDIB", 0!w:=Hex$(x,2), 0!h:=Hex$(y, 2)
\\ fill white (all 255)
\\ Str$(string) convert to ascii, so we get all characters from words width to byte width
Return Image1, 0!lines:=Str$(String$(chrcode$(255), Len(rasterline)*y))
Buffer Clear Pad as Byte*4
SetPixel=Lambda Image1, Pad,aLines=Len(Raster)-Len(Rasterline), blines=-Len(Rasterline) (x, y, c) ->{
where=alines+3*x+blines*y
if c>0 then c=color(c)
c-!
Return Pad, 0:=c as long
Return Image1, 0!where:=Eval(Pad, 2) as byte, 0!where+1:=Eval(Pad, 1) as byte, 0!where+2:=Eval(Pad, 0) as byte
}
GetPixel=Lambda Image1,aLines=Len(Raster)-Len(Rasterline), blines=-Len(Rasterline) (x,y) ->{
where=alines+3*x+blines*y
=color(Eval(image1, where+2 as byte), Eval(image1, where+1 as byte), Eval(image1, where as byte))
}
StrDib$=Lambda$ Image1, Raster -> {
=Eval$(Image1, 0, Len(Raster))
}
CopyImage=Lambda Image1 (image$) -> {
if left$(image$,12)=Eval$(Image1, 0, 24 ) Then {
Return Image1, 0:=Image$
} Else Error "Can't Copy Image"
}
Export2File=Lambda Image1, x, y (f) -> {
\\ use this between open and close
Print #f, "P3"
Print #f,"# Created using M2000 Interpreter"
Print #f, x;" ";y
Print #f, 255
x2=x-1
where=24
For y1= 0 to y-1 {
a$=""
For x1=0 to x2 {
Print #f, a$;Eval(Image1, where +2 as byte);" ";
Print #f, Eval(Image1, where+1 as byte);" ";
Print #f, Eval(Image1, where as byte);
where+=3
a$=" "
}
Print #f
m=where mod 4
if m<>0 then where+=4-m
}
}
Group Bitmap {
SetPixel=SetPixel
GetPixel=GetPixel
Image$=StrDib$
Copy=CopyImage
ToFile=Export2File
}
=Bitmap
}
A=Bitmap(10, 10)
Call A.SetPixel(5,5, color(128,0,255))
Open "A2.PPM" for Output as #F
Call A.ToFile(F)
Close #f
' is the same as this one
Try {
Open "A.PPM" for Output as #F
Print #f, "P3"
Print #f,"# Created using M2000 Interpreter"
Print #f, 10;" ";10
Print #f, 255
For y=10-1 to 0 {
a$=""
For x=0 to 10-1 {
rgb=-A.GetPixel(x, y)
Print #f, a$;Binary.And(rgb, 0xFF); " ";
Print #f, Binary.And(Binary.Shift(rgb, -8), 0xFF); " ";
Print #f, Binary.Shift(rgb, -16);
a$=" "
}
Print #f
}
Close #f
}
}
Checkit
|
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #PureBasic | PureBasic | Structure PPMColor
r.c
g.c
b.c
EndStructure
Procedure LoadImagePPM(Image, file$)
; Author Roger Rösch (Nickname Macros)
IDFile = ReadFile(#PB_Any, file$)
If IDFile
If CreateImage(Image, 1, 1)
Format$ = ReadString(IDFile)
ReadString(IDFile) ; skip comment
Dimensions$ = ReadString(IDFile)
w = Val(StringField(Dimensions$, 1, " "))
h = Val(StringField(Dimensions$, 2, " "))
ResizeImage(Image, w, h)
StartDrawing(ImageOutput(Image))
max = Val(ReadString(IDFile)) ; Maximal Value for a color
Select Format$
Case "P3" ; File in ASCII format
; Exract everey number remaining in th file into an array using an RegEx
Stringlen = Lof(IDFile) - Loc(IDFile)
content$ = Space(Stringlen)
Dim color.s(0)
ReadData(IDFile, @content$, Stringlen)
CreateRegularExpression(1, "\d+")
ExtractRegularExpression(1, content$, color())
; Plot color information on our empty Image
For y = 0 To h - 1
For x = 0 To w - 1
pos = (y*w + x)*3
r=Val(color(pos))*255 / max
g=Val(color(pos+1))*255 / max
b=Val(color(pos+2))*255 / max
Plot(x, y, RGB(r,g,b))
Next
Next
Case "P6" ;File In binary format
; Read whole bytes into a buffer because its faster than reading single ones
Bufferlen = Lof(IDFile) - Loc(IDFile)
*Buffer = AllocateMemory(Bufferlen)
ReadData(IDFile, *Buffer, Bufferlen)
; Plot color information on our empty Image
For y = 0 To h - 1
For x = 0 To w - 1
*color.PPMColor = pos + *Buffer
Plot(x, y, RGB(*color\r*255 / max, *color\g*255 / max, *color\b*255 / max))
pos + 3
Next
Next
EndSelect
StopDrawing()
; Return 1 if successfully loaded to behave as other PureBasic functions
ProcedureReturn 1
EndIf
EndIf
EndProcedure |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #AutoHotkey | AutoHotkey | BEGIN {
# Do not put quotes round the numeric values, or the tests will fail
a = 1 # True
b = 0 # False
# Boolean evaluations
if (a) { print "first test a is true" } # This should print
if (b) { print "second test b is true" } # This should not print
if (!a) { print "third test a is false" } # This should not print
if (!b) { print "forth test b is false" } # This should print
# Boolean evaluation using comparison against zero
if (a == 0) { print "fifth test a is false" } # This should not print
if (b == 0) { print "sixth test b is false" } # This should print
if (a != 0) { print "seventh test a is true" } # This should print
if (b != 0) { print "eighth test b is true" } # This should not print
} |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #Avail | Avail | BEGIN {
# Do not put quotes round the numeric values, or the tests will fail
a = 1 # True
b = 0 # False
# Boolean evaluations
if (a) { print "first test a is true" } # This should print
if (b) { print "second test b is true" } # This should not print
if (!a) { print "third test a is false" } # This should not print
if (!b) { print "forth test b is false" } # This should print
# Boolean evaluation using comparison against zero
if (a == 0) { print "fifth test a is false" } # This should not print
if (b == 0) { print "sixth test b is false" } # This should print
if (a != 0) { print "seventh test a is true" } # This should print
if (b != 0) { print "eighth test b is true" } # This should not print
} |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Scheme | Scheme | ;
; Works with R7RS-compatible Schemes (e.g. Chibi).
; Also current versions of Chicken, Gauche and Kawa.
;
(cond-expand
(chicken (use srfi-13))
(gauche (use srfi-13))
(kawa (import (srfi :13)))
(else (import (scheme base) (scheme write)))) ; R7RS
(define msg "The quick brown fox jumps over the lazy dog.")
(define key 13)
(define (caesar char)
(define A (char->integer #\A))
(define Z (char->integer #\Z))
(define a (char->integer #\a))
(define z (char->integer #\z))
(define c (char->integer char))
(integer->char
(cond ((<= A c Z) (+ A (modulo (+ key (- c A)) 26)))
((<= a c z) (+ a (modulo (+ key (- c a)) 26)))
(else c)))) ; Return other characters verbatim.
(display (string-map caesar msg))
(newline)
|
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #OCaml | OCaml | let write_7bit_string ~filename ~str =
let oc = open_out filename in
let ob = IO.output_bits(IO.output_channel oc) in
String.iter (fun c -> IO.write_bits ob 7 (int_of_char c)) str;
IO.flush_bits ob;
close_out oc;
;; |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Perl | Perl | #! /usr/bin/perl
use strict;
# $buffer = write_bits(*STDOUT, $buffer, $number, $bits)
sub write_bits( $$$$ )
{
my ($out, $l, $num, $q) = @_;
$l .= substr(unpack("B*", pack("N", $num)),
-$q);
if ( (length($l) > 8) ) {
my $left = substr($l, 8);
print $out pack("B8", $l);
$l = $left;
}
return $l;
}
# flush_bits(*STDOUT, $buffer)
sub flush_bits( $$ )
{
my ($out, $b) = @_;
print $out pack("B*", $b);
}
# ($val, $buf) = read_bits(*STDIN, $buf, $n)
sub read_bits( $$$ )
{
my ( $in, $b, $n ) = @_;
# we put a limit in the number of bits we can read
# with one shot; this should mirror the limit of the max
# integer value perl can hold
if ( $n > 32 ) { return 0; }
while ( length($b) < $n ) {
my $v;
my $red = read($in, $v, 1);
if ( $red < 1 ) { return ( 0, -1 ); }
$b .= substr(unpack("B*", $v), -8);
}
my $bits = "0" x ( 32-$n ) . substr($b, 0, $n);
my $val = unpack("N", pack("B32", $bits));
$b = substr($b, $n);
return ($val, $b);
} |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Mathematica.2F_Wolfram_Language | Mathematica/ Wolfram Language | Export["file.ppm",image,"PPM"] |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #MATLAB_.2F_Octave | MATLAB / Octave | R=[255,0,0;255,255,0];
G=[0,255,0;255,255,0];
B=[0,0,255;0,0,0];
r = R'; r(:);
g = R'; g(:);
b = R'; b(:);
fid=fopen('p6.ppm','w');
fprintf(fid,'P6\n%i %i\n255\n',size(R));
fwrite(fid,[r,g,b]','uint8');
fclose(fid); |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Python | Python | # With help from http://netpbm.sourceforge.net/doc/ppm.html
# String masquerading as ppm file (version P3)
import io
ppmtxt = '''P3
# feep.ppm
4 4
15
0 0 0 0 0 0 0 0 0 15 0 15
0 0 0 0 15 7 0 0 0 0 0 0
0 0 0 0 0 0 0 15 7 0 0 0
15 0 15 0 0 0 0 0 0 0 0 0
'''
def tokenize(f):
for line in f:
if line[0] != '#':
for t in line.split():
yield t
def ppmp3tobitmap(f):
t = tokenize(f)
nexttoken = lambda : next(t)
assert 'P3' == nexttoken(), 'Wrong filetype'
width, height, maxval = (int(nexttoken()) for i in range(3))
bitmap = Bitmap(width, height, Colour(0, 0, 0))
for h in range(height-1, -1, -1):
for w in range(0, width):
bitmap.set(w, h, Colour( *(int(nexttoken()) for i in range(3))))
return bitmap
print('Original Colour PPM file')
print(ppmtxt)
ppmfile = io.StringIO(ppmtxt)
bitmap = ppmp3tobitmap(ppmfile)
print('Grey PPM:')
bitmap.togreyscale()
ppmfileout = io.StringIO('')
bitmap.writeppmp3(ppmfileout)
print(ppmfileout.getvalue())
'''
The print statements above produce the following output:
Original Colour PPM file
P3
# feep.ppm
4 4
15
0 0 0 0 0 0 0 0 0 15 0 15
0 0 0 0 15 7 0 0 0 0 0 0
0 0 0 0 0 0 0 15 7 0 0 0
15 0 15 0 0 0 0 0 0 0 0 0
Grey PPM:
P3
# generated from Bitmap.writeppmp3
4 4
11
0 0 0 0 0 0 0 0 0 4 4 4
0 0 0 11 11 11 0 0 0 0 0 0
0 0 0 0 0 0 11 11 11 0 0 0
4 4 4 0 0 0 0 0 0 0 0 0
''' |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #AWK | AWK | BEGIN {
# Do not put quotes round the numeric values, or the tests will fail
a = 1 # True
b = 0 # False
# Boolean evaluations
if (a) { print "first test a is true" } # This should print
if (b) { print "second test b is true" } # This should not print
if (!a) { print "third test a is false" } # This should not print
if (!b) { print "forth test b is false" } # This should print
# Boolean evaluation using comparison against zero
if (a == 0) { print "fifth test a is false" } # This should not print
if (b == 0) { print "sixth test b is false" } # This should print
if (a != 0) { print "seventh test a is true" } # This should print
if (b != 0) { print "eighth test b is true" } # This should not print
} |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #Axe | Axe | 10 LET A%=0
20 LET B%=NOT(A%)
30 PRINT "THIS VERSION OF BASIC USES"
40 PRINT B%; " AS ITS TRUE VALUE"
50 IF A% THEN PRINT "TEST ONE DOES NOT PRINT"
60 IF B% THEN PRINT "TEST TWO DOES PRINT"
70 IF A%=0 THEN PRINT "TEST THREE (FALSE BY COMPARISON) DOES PRINT"
80 IF B%=0 THEN PRINT "TEST FOUR (FALSE BY COMPARISON) DOES NOT PRINT"
90 IF A%<>0 THEN PRINT "TEST FIVE (TRUE BY COMPARISON) DOES NOT PRINT"
100 IF B%<>0 THEN PRINT "TEST SIX (TRUE BY COMPARISON) DOES PRINT"
110 END |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #sed | sed | #!/bin/sed -rf
# Input: <number 0..25>\ntext to encode
/^[0-9]+$/ {
# validate a number and translate it to analog form
s/$/;9876543210dddddddddd/
s/([0-9]);.*\1.{10}(.?)/\2/
s/2/11/
s/1/dddddddddd/g
/[3-9]|d{25}d+/ {
s/.*/Error: Key must be <= 25/
q
}
# append from-table
s/$/\nabcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/
# .. and to-table
s/$/abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ/
# rotate to-table, lower and uppercase independently, removing one `d' at a time
: rotate
s/^d(.*\n[^Z]+Z)(.)(.{25})(.)(.{25})/\1\3\2\5\4/
t rotate
s/\n//
h
d
}
# use \n to mark character to convert
s/^/\n/
# append conversion table to pattern space
G
: loop
# look up converted character and place it instead of old one
s/\n(.)(.*\n.*\1.{51}(.))/\n\3\2/
# advance \n even if prev. command fails, thus skip non-alphabetical characters
/\n\n/! s/\n([^\n])/\1\n/
t loop
s/\n\n.*// |
http://rosettacode.org/wiki/Bitmap/Histogram | Bitmap/Histogram | Extend the basic bitmap storage defined on this page to support dealing with image histograms. The image histogram contains for each luminance the count of image pixels having this luminance. Choosing a histogram representation take care about the data type used for the counts. It must have range of at least 0..NxM, where N is the image width and M is the image height.
Test task
Histogram is useful for many image processing operations. As an example, use it to convert an image into black and white art. The method works as follows:
Convert image to grayscale;
Compute the histogram
Find the median: defined as the luminance such that the image has an approximately equal number of pixels with lesser and greater luminance.
Replace each pixel of luminance lesser than the median to black, and others to white.
Use read/write ppm file, and grayscale image solutions.
| #Action.21 | Action! | INCLUDE "H6:LOADPPM5.ACT"
DEFINE HISTSIZE="256"
PROC PutBigPixel(INT x,y BYTE col)
IF x>=0 AND x<=79 AND y>=0 AND y<=47 THEN
y==LSH 2
col==RSH 4
IF col<0 THEN col=0
ELSEIF col>15 THEN col=15 FI
Color=col
Plot(x,y)
DrawTo(x,y+3)
FI
RETURN
PROC DrawImage(GrayImage POINTER image INT x,y)
INT i,j
BYTE c
FOR j=0 TO image.gh-1
DO
FOR i=0 TO image.gw-1
DO
c=GetGrayPixel(image,i,j)
PutBigPixel(x+i,y+j,c)
OD
OD
RETURN
PROC CalcHistogram(GrayImage POINTER image INT ARRAY hist)
INT i,j
BYTE c
Zero(hist,HISTSIZE*2)
FOR j=0 TO image.gh-1
DO
FOR i=0 TO image.gw-1
DO
c=GetGrayPixel(image,i,j)
hist(c)==+1
OD
OD
RETURN
BYTE FUNC CalcThresholdValue(INT width,height INT ARRAY hist)
INT i,sum,total,curr
total=width*height
sum=0
FOR i=0 TO HISTSIZE-1
DO
curr=hist(i)
IF sum>=(total-curr)/2 THEN
RETURN (i)
FI
sum==+curr
OD
RETURN (HISTSIZE-1)
PROC Binarize(GrayImage POINTER src,dst BYTE threshold)
INT i,j
BYTE c
FOR j=0 TO src.gh-1
DO
FOR i=0 TO src.gw-1
DO
c=GetGrayPixel(src,i,j)
IF c<threshold THEN
c=0
ELSE
c=255
FI
SetGrayPixel(dst,i,j,c)
OD
OD
RETURN
PROC Main()
BYTE CH=$02FC ;Internal hardware value for last key pressed
BYTE ARRAY dataIn(900),dataOut(900)
GrayImage in,out
INT ARRAY hist(HISTSIZE)
BYTE threshold
INT size=[30],x,y
Put(125) PutE() ;clear the screen
InitGrayImage(in,size,size,dataIn)
InitGrayImage(out,size,size,dataOut)
PrintE("Loading source image...")
LoadPPM5(in,"H6:LENA30G.PPM")
PrintE("Calc histogram...")
CalcHistogram(in,hist)
PrintE("Calc threshold value...")
threshold=CalcThresholdValue(in.gw,in.gh,hist)
PrintE("Binarization...")
Binarize(in,out,threshold)
Graphics(9)
x=(40-size)/2
y=(48-size)/2
DrawImage(in,x,y)
DrawImage(out,x+40,y)
DO UNTIL CH#$FF OD
CH=$FF
RETURN |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #Phix | Phix | without js -- (file i/o)
enum FN, V, BITS -- fields of a bitwiseioreader/writer
function new_bitwiseio(string filename, mode)
integer fn = open(filename,mode)
return {fn,0,0} -- ie {FN,V=0,BITS=0}
end function
function new_bitwiseiowriter(string filename)
return new_bitwiseio(filename,"wb")
end function
function new_bitwiseioreader(string filename)
return new_bitwiseio(filename,"rb")
end function
function write_bits(sequence writer, integer v, bits)
integer {fn,wv,wb} = writer,
p2 = power(2,bits), ch
if v!=and_bits(v,p2*2-1) then ?9/0 end if
wv = wv*p2+v
wb += bits
while wb>=8 do
wb -= 8
p2 = power(2,wb)
ch = floor(wv/p2)
puts(fn,ch)
wv -= ch*p2
end while
if wv>=#100 then ?9/0 end if
if wb>=8 then ?9/0 end if
writer[V]= wv
writer[BITS]= wb
return writer
end function
function close_bitwiseiowriter(sequence writer)
integer {fn,wv,wb} = writer
if wb then
if wb>=8 then ?9/0 end if -- sanity check
writer = write_bits(writer,0,8-wb)
end if
if writer[V]!=0 then ?9/0 end if
if writer[BITS]!=0 then ?9/0 end if
close(fn)
writer[FN]=-1
return writer
end function
function read_bits(sequence reader, integer bits)
integer {fn,rv,rb} = reader, ch, p2
while bits>rb do
ch = getc(fn)
if ch=-1 then return {-1,reader} end if
rv = rv*#100+ch
rb += 8
end while
rb -= bits
p2 = power(2,rb)
ch = floor(rv/p2)
rv -= ch*p2
reader[V]= rv
reader[BITS]= rb
return {ch,reader}
end function
function as_hexb(string s, fmt="%02x ")
-- helper funtion, returns hex string, or binary if fmt="%08b "
string res = ""
for i=1 to length(s) do
res &= sprintf(fmt,s[i])
end for
return trim(res)
end function
constant test = "This is a test."
--constant test = "This is a test"
--constant test = "abcdefghijk"
--constant test = "STRING"
--constant test = "This is an ascii string that will be crunched, written, read and expanded."
printf(1,"\"%s\" as bytes: %s (length %d)\n",{test,as_hexb(test),length(test)})
printf(1," original bits: %s\n",{as_hexb(test,"%08b ")})
sequence writer = new_bitwiseiowriter("test.bin")
for i=1 to length(test) do
writer = write_bits(writer,test[i],7)
end for
writer = close_bitwiseiowriter(writer)
integer fn = open("test.bin","rb")
string bytes = get_text(fn,GT_WHOLE_FILE)
printf(1,"Written bitstream: %s\n",{as_hexb(bytes,"%08b ")})
printf(1,"Written bytes: %s (length %d)\n",{as_hexb(bytes),length(bytes)})
close(fn)
sequence reader = new_bitwiseioreader("test.bin")
bytes = ""
integer ch
while true do
{ch,reader} = read_bits(reader,7)
if ch=-1 then exit end if
bytes &= ch
end while
printf(1,"\"%s\" as bytes: %s (length %d)\n",{bytes,as_hexb(bytes),length(bytes)})
|
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Modula-3 | Modula-3 | INTERFACE PPM;
IMPORT Bitmap, Pathname;
PROCEDURE Create(imgfile: Pathname.T; img: Bitmap.T);
END PPM. |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Nim | Nim | import bitmap
import streams
#---------------------------------------------------------------------------------------------------
proc writePPM*(img: Image, stream: Stream) =
## Write an image to a PPM stream.
stream.writeLine("P6 ", $img.w, " ", $img.h, " 255")
for x, y in img.indices:
stream.write(chr(img[x, y].r))
stream.write(chr(img[x, y].g))
stream.write(chr(img[x, y].b))
#---------------------------------------------------------------------------------------------------
proc writePPM*(img: Image; filename: string) =
## Write an image in a PPM file.
var file = openFileStream(filename, fmWrite)
img.writePPM(file)
file.close()
#———————————————————————————————————————————————————————————————————————————————————————————————————
when isMainModule:
var image = newImage(100, 50)
image.fill(color(255, 0, 0))
for row in 10..20:
for col in 0..<image.w:
image[col, row] = color(0, 255, 0)
for row in 30..40:
for col in 0..<image.w:
image[col, row] = color(0, 0, 255)
image.writePPM("output.ppm") |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Racket | Racket |
#lang racket
(require racket/draw)
(define (read-ppm port)
(parameterize ([current-input-port port])
(define magic (read))
(define width (read))
(define height (read))
(define maxcol (read))
(define bm (make-object bitmap% width height))
(define dc (new bitmap-dc% [bitmap bm]))
(send dc set-smoothing 'unsmoothed)
(define (adjust v) (* 255 (/ v maxcol)))
(for/list ([x width])
(for/list ([y height])
(define red (read))
(define green (read))
(define blue (read))
(define color (make-object color% (adjust red) (adjust green) (adjust blue)))
(send dc set-pen color 1 'solid)
(send dc draw-point x y)))
bm))
|
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #Raku | Raku | class Pixel { has UInt ($.R, $.G, $.B) }
class Bitmap {
has UInt ($.width, $.height);
has Pixel @.data;
}
role PGM {
has @.GS;
method P5 returns Blob {
"P5\n{self.width} {self.height}\n255\n".encode('ascii')
~ Blob.new: self.GS
}
}
sub load-ppm ( $ppm ) {
my $fh = $ppm.IO.open( :enc('ISO-8859-1') );
my $type = $fh.get;
my ($width, $height) = $fh.get.split: ' ';
my $depth = $fh.get;
Bitmap.new( width => $width.Int, height => $height.Int,
data => ( $fh.slurp.ords.rotor(3).map:
{ Pixel.new(R => $_[0], G => $_[1], B => $_[2]) } )
)
}
sub grayscale ( Bitmap $bmp ) {
$bmp.GS = map { (.R*0.2126 + .G*0.7152 + .B*0.0722).round(1) min 255 }, $bmp.data;
}
my $filename = './camelia.ppm';
my Bitmap $b = load-ppm( $filename ) but PGM;
grayscale($b);
'./camelia-gs.pgm'.IO.open(:bin, :w).write: $b.P5; |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #BASIC | BASIC | 10 LET A%=0
20 LET B%=NOT(A%)
30 PRINT "THIS VERSION OF BASIC USES"
40 PRINT B%; " AS ITS TRUE VALUE"
50 IF A% THEN PRINT "TEST ONE DOES NOT PRINT"
60 IF B% THEN PRINT "TEST TWO DOES PRINT"
70 IF A%=0 THEN PRINT "TEST THREE (FALSE BY COMPARISON) DOES PRINT"
80 IF B%=0 THEN PRINT "TEST FOUR (FALSE BY COMPARISON) DOES NOT PRINT"
90 IF A%<>0 THEN PRINT "TEST FIVE (TRUE BY COMPARISON) DOES NOT PRINT"
100 IF B%<>0 THEN PRINT "TEST SIX (TRUE BY COMPARISON) DOES PRINT"
110 END |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #Batch_File | Batch File |
@echo off
::true
set "a=x"
::false
set "b="
if defined a (
echo a is true
) else (
echo a is false
)
if defined b (
echo b is true
) else (
echo b is false
)
pause>nul
|
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #Seed7 | Seed7 | $ include "seed7_05.s7i";
const func string: rot (in string: stri, in integer: encodingKey) is func
result
var string: encodedStri is "";
local
var char: ch is ' ';
var integer: index is 0;
begin
encodedStri := stri;
for ch key index range stri do
if ch >= 'a' and ch <= 'z' then
ch := chr((ord(ch) - ord('a') + encodingKey) rem 26 + ord('a'));
elsif ch >= 'A' and ch <= 'Z' then
ch := chr((ord(ch) - ord('A') + encodingKey) rem 26 + ord('A'));
end if;
encodedStri @:= [index] ch;
end for;
end func;
const proc: main is func
local
const integer: exampleKey is 3;
const string: testText is "The five boxing wizards jump quickly";
begin
writeln("Original: " <& testText);
writeln("Encrypted: " <& rot(testText, exampleKey));
writeln("Decrypted: " <& rot(rot(testText, exampleKey), 26 - exampleKey));
end func; |
http://rosettacode.org/wiki/Bitmap/Histogram | Bitmap/Histogram | Extend the basic bitmap storage defined on this page to support dealing with image histograms. The image histogram contains for each luminance the count of image pixels having this luminance. Choosing a histogram representation take care about the data type used for the counts. It must have range of at least 0..NxM, where N is the image width and M is the image height.
Test task
Histogram is useful for many image processing operations. As an example, use it to convert an image into black and white art. The method works as follows:
Convert image to grayscale;
Compute the histogram
Find the median: defined as the luminance such that the image has an approximately equal number of pixels with lesser and greater luminance.
Replace each pixel of luminance lesser than the median to black, and others to white.
Use read/write ppm file, and grayscale image solutions.
| #Ada | Ada | type Pixel_Count is mod 2**64;
type Histogram is array (Luminance) of Pixel_Count;
function Get_Histogram (Picture : Grayscale_Image) return Histogram is
Result : Histogram := (others => 0);
begin
for I in Picture'Range (1) loop
for J in Picture'Range (2) loop
declare
Count : Pixel_Count renames Result (Picture (I, J));
begin
Count := Count + 1;
end;
end loop;
end loop;
return Result;
end Get_Histogram; |
http://rosettacode.org/wiki/Bitmap/Histogram | Bitmap/Histogram | Extend the basic bitmap storage defined on this page to support dealing with image histograms. The image histogram contains for each luminance the count of image pixels having this luminance. Choosing a histogram representation take care about the data type used for the counts. It must have range of at least 0..NxM, where N is the image width and M is the image height.
Test task
Histogram is useful for many image processing operations. As an example, use it to convert an image into black and white art. The method works as follows:
Convert image to grayscale;
Compute the histogram
Find the median: defined as the luminance such that the image has an approximately equal number of pixels with lesser and greater luminance.
Replace each pixel of luminance lesser than the median to black, and others to white.
Use read/write ppm file, and grayscale image solutions.
| #BBC_BASIC | BBC BASIC | INSTALL @lib$+"SORTLIB"
Sort% = FN_sortinit(0,0)
Width% = 200
Height% = 200
VDU 23,22,Width%;Height%;8,16,16,128
*display c:\lenagrey
DIM hist%(255), idx%(255)
FOR i% = 0 TO 255 : idx%(i%) = i% : NEXT
REM Build histogram:
FOR y% = 0 TO Height%-1
FOR x% = 0 TO Width%-1
l% = FNgetpixel(x%,y%) AND &FF
hist%(l%) += 1
NEXT
NEXT y%
REM Sort histogram:
C% = 256
CALL Sort%, hist%(0), idx%(0)
REM Find median:
total% = SUM(hist%())
half% = 0
FOR i% = 0 TO 255
half% += hist%(i%)
IF half% >= total%/2 THEN
median% = idx%(i%)
EXIT FOR
ENDIF
NEXT
REM Display black & white version:
FOR y% = 0 TO Height%-1
FOR x% = 0 TO Width%-1
l% = FNgetpixel(x%,y%) AND &FF
IF l% > median% THEN
PROCsetpixel(x%,y%,255,255,255)
ELSE
PROCsetpixel(x%,y%,0,0,0)
ENDIF
NEXT
NEXT y%
END
DEF PROCsetpixel(x%,y%,r%,g%,b%)
COLOUR 1,r%,g%,b%
GCOL 1
LINE x%*2,y%*2,x%*2,y%*2
ENDPROC
DEF FNgetpixel(x%,y%)
LOCAL col%
col% = TINT(x%*2,y%*2)
SWAP ?^col%,?(^col%+2)
= col% |
http://rosettacode.org/wiki/Bitwise_operations | Bitwise operations |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |
Comparison |
Matching
Memory Operations
Pointers & references |
Addresses
Task
Write a routine to perform a bitwise AND, OR, and XOR on two integers, a bitwise NOT on the first integer, a left shift, right shift, right arithmetic shift, left rotate, and right rotate.
All shifts and rotates should be done on the first integer with a shift/rotate amount of the second integer.
If any operation is not available in your language, note it.
| #11l | 11l | V x = 10
V y = 2
print(‘x = ’x)
print(‘y = ’y)
print(‘NOT x = ’(-)x)
print(‘x AND y = ’(x [&] y))
print(‘x OR y = ’(x [|] y))
print(‘x XOR y = ’(x (+) y))
print(‘x SHL y = ’(x << y))
print(‘x SHR y = ’(x >> y))
print(‘x ROL y = ’rotl(x, y))
print(‘x ROR y = ’rotr(x, y)) |
http://rosettacode.org/wiki/Bitmap/Midpoint_circle_algorithm | Bitmap/Midpoint circle algorithm | Task
Using the data storage type defined on this page for raster images,
write an implementation of the midpoint circle algorithm (also known as Bresenham's circle algorithm).
(definition on Wikipedia).
| #11l | 11l | T Colour
Byte r, g, b
F (r, g, b)
.r = r
.g = g
.b = b
F ==(other)
R .r == other.r & .g == other.g & .b == other.b
V black = Colour(0, 0, 0)
V white = Colour(255, 255, 255)
T Bitmap
Int width, height
Colour background
[[Colour]] map
F (width = 40, height = 40, background = white)
assert(width > 0 & height > 0)
.width = width
.height = height
.background = background
.map = (0 .< height).map(h -> (0 .< @width).map(w -> @@background))
F fillrect(x, y, width, height, colour = black)
assert(x >= 0 & y >= 0 & width > 0 & height > 0)
L(h) 0 .< height
L(w) 0 .< width
.map[y + h][x + w] = colour
F chardisplay()
V txt = .map.map(row -> row.map(bit -> (I bit == @@.background {‘ ’} E ‘@’)).join(‘’))
txt = txt.map(row -> ‘|’row‘|’)
txt.insert(0, ‘+’(‘-’ * .width)‘+’)
txt.append(‘+’(‘-’ * .width)‘+’)
print(reversed(txt).join("\n"))
F set(x, y, colour = black)
.map[y][x] = colour
F get(x, y)
R .map[y][x]
F circle(x0, y0, radius, colour = black)
V f = 1 - radius
V ddf_x = 1
V ddf_y = -2 * radius
V x = 0
V y = radius
.set(x0, y0 + radius, colour)
.set(x0, y0 - radius, colour)
.set(x0 + radius, y0, colour)
.set(x0 - radius, y0, colour)
L x < y
I f >= 0
y--
ddf_y += 2
f += ddf_y
x++
ddf_x += 2
f += ddf_x
.set(x0 + x, y0 + y, colour)
.set(x0 - x, y0 + y, colour)
.set(x0 + x, y0 - y, colour)
.set(x0 - x, y0 - y, colour)
.set(x0 + y, y0 + x, colour)
.set(x0 - y, y0 + x, colour)
.set(x0 + y, y0 - x, colour)
.set(x0 - y, y0 - x, colour)
V bitmap = Bitmap(25, 25)
bitmap.circle(x0' 12, y0' 12, radius' 12)
bitmap.chardisplay() |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #PicoLisp | PicoLisp | (de write7bitwise (Lst)
(let (Bits 0 Byte)
(for N Lst
(if (=0 Bits)
(setq Bits 7 Byte (* 2 N))
(wr (| Byte (>> (dec 'Bits) N)))
(setq Byte (>> (- Bits 8) N)) ) )
(unless (=0 Bits)
(wr Byte) ) ) )
(de read7bitwise ()
(make
(let (Bits 0 Byte)
(while (rd 1)
(let N @
(link
(if (=0 Bits)
(>> (one Bits) N)
(| Byte (>> (inc 'Bits) N)) ) )
(setq Byte (& 127 (>> (- Bits 7) N))) ) )
(when (= 7 Bits)
(link Byte) ) ) ) ) |
http://rosettacode.org/wiki/Bitwise_IO | Bitwise IO | The aim of this task is to write functions (or create a class if your
language is Object Oriented and you prefer) for reading and writing sequences of
bits, most significant bit first. While the output of a asciiprint "STRING" is the ASCII byte sequence
"S", "T", "R", "I", "N", "G", the output of a "print" of the bits sequence
0101011101010 (13 bits) must be 0101011101010; real I/O is performed always
quantized by byte (avoiding endianness issues and relying on underlying
buffering for performance), therefore you must obtain as output the bytes
0101 0111 0101 0000 (bold bits are padding bits), i.e. in hexadecimal 57 50.
As test, you can implement a rough (e.g. don't care about error handling or
other issues) compression/decompression program for ASCII sequences
of bytes, i.e. bytes for which the most significant bit is always unused, so that you can write
seven bits instead of eight (each 8 bytes of input, we write 7 bytes of output).
These bit oriented I/O functions can be used to implement compressors and
decompressors; e.g. Dynamic and Static Huffman encodings use variable length
bits sequences, while LZW (see LZW compression) use fixed or variable words
nine (or more) bits long.
Limits in the maximum number of bits that can be written/read in a single read/write operation are allowed.
Errors handling is not mandatory
| #PL.2FI | PL/I | declare onebit bit(1) aligned, bs bit (1000) varying aligned;
on endfile (sysin) go to ending;
bs = ''b;
do forever;
get edit (onebit) (F(1));
bs = bs || onebit;
end;
ending:
bs = bs || copy('0'b, mod(length(bs), 8) );
/* pad length to a multiple of 8 */
put edit (bs) (b); |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #OCaml | OCaml | let output_ppm ~oc ~img:(_, r_channel, g_channel, b_channel) =
let width = Bigarray.Array2.dim1 r_channel
and height = Bigarray.Array2.dim2 r_channel in
Printf.fprintf oc "P6\n%d %d\n255\n" width height;
for y = 0 to pred height do
for x = 0 to pred width do
output_char oc (char_of_int r_channel.{x,y});
output_char oc (char_of_int g_channel.{x,y});
output_char oc (char_of_int b_channel.{x,y});
done;
done;
output_char oc '\n';
flush oc;
;; |
http://rosettacode.org/wiki/Bitmap/Write_a_PPM_file | Bitmap/Write a PPM file | Using the data storage type defined on this page for raster images, write the image to a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
| #Oz | Oz | functor
import
Bitmap
Open
export
%% Read
Write
define
%% Omitted: Read
proc {Write B=bitmap(array2d(width:W height:H ...)) Filename}
F = {New Open.file init(name:Filename flags:[write create truncate binary])}
proc {WriteColor8 color(R G B)}
{F write(vs:[R G B])}
end
fun {ToBytes C}
[C div 0x100 C mod 0x100]
end
proc {WriteColor16 color(R G B)}
{F write(vs:{Flatten {Map [R G B] ToBytes}})}
end
MaxCol = {Bitmap.maxValue B}
MaxVal#Writer = if MaxCol =< 0xff then 0xff#WriteColor8
else 0xffff#WriteColor16
end
Header = "P6\n"#W#" "#H#" "#MaxVal#"\n"
in
try
{F write(vs:Header)}
{Bitmap.forAllPixels B Writer}
finally
{F close}
end
end
end |
http://rosettacode.org/wiki/Bitmap/Read_a_PPM_file | Bitmap/Read a PPM file | Using the data storage type defined on this page for raster images, read an image from a PPM file (binary P6 prefered).
(Read the definition of PPM file on Wikipedia.)
Task: Use write ppm file solution and grayscale image solution with this one in order to convert a color image to grayscale one.
| #REXX | REXX | /*REXX program reads a PPM formatted image file, and creates a gray─scale image of it. */
parse arg iFN oFN /*obtain optional argument from the CL.*/
if iFN=='' | iFN=="," then iFN= 'Lenna50' /*Not specified? Then use the default.*/
if oFN=='' | oFN=="," then oFN= 'greyscale' /* " " " " " " */
iFID= iFN'.ppm'; oFID= oFN'.ppm' /*complete the input and output FIDs.*/
call charin iFID, 1, 0 /*set the position of the input file. */
y=charin(iFID, , copies(9, digits() ) ) /*read the entire input file ───► X */
parse var y id 3 c 4 3 width height # pixels /*extract header info from the PPM hdr.*/
LF= 'a'x /*define a comment separator (in hdr).*/ /* ◄─── LF delimiters & comments*/
if c==LF then do; commentEND=pos(LF, y, 4) /*point to the last char in the comment*/ /* ◄─── LF delimiters & comments*/
parse var y =(commentEND) +1 width height # pixels /* ◄─── LF delimiters & comments*/
end /* ◄─── LF delimiters & comments*/
/* [↓] has an alternative delimiter? */ /* ◄─── LF delimiters & comments*/
z=pos(LF, height); if z\==0 then parse var height height =(z) +1 # pixels /* ◄─── LF delimiters & comments*/
z=pos(LF, # ); if z\==0 then parse var # # =(z) +1 pixels /* ◄─── LF delimiters & comments*/
chunk=4000 /*chunk size to be written at one time.*/
LenPixels= length(pixels)
do j=0 for 256; _=d2c(j); @._=j; @@.j=_ /*build two tables for fast conversions*/
end /*j*/
call charout oFID, , 1 /*set the position of the output file. */
call charout oFID, id || width height #' ' /*write the header followed by a blank.*/
!=1
do until !>=LenPixels; $= /*$: partial output string so far.*/
do !=! by 3 for chunk /*chunk: # pixels converted at 1 time.*/
parse var pixels =(!) r +1 g +1 b +1 /*obtain the next RGB of a PPM pixel.*/
if r=='' then leave /*has the end─of─string been reached? */
_=(.2126*@.r + .7152*@.g + .0722*@.b )%1 /*an integer RGB greyscale of a pixel. */
$=$ || @@._ || @@._ || @@._ /*lump (grey) R G B pixels together. */
end /*!*/ /* [↑] D2C converts decimal ───► char*/
call charout oFID, $ /*write the next bunch of pixels. */
end /*until*/
call charout oFID /*close the output file just to be safe*/
say 'File ' oFID " was created." /*stick a fork in it, we're all done. */ |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #bc | bc | {1?34}
34
{⟨⟩?34}
ERROR |
http://rosettacode.org/wiki/Boolean_values | Boolean values | Task
Show how to represent the boolean states "true" and "false" in a language.
If other objects represent "true" or "false" in conditionals, note it.
Related tasks
Logical operations
| #Befunge | Befunge | {1?34}
34
{⟨⟩?34}
ERROR |
http://rosettacode.org/wiki/Caesar_cipher | Caesar cipher |
Task
Implement a Caesar cipher, both encoding and decoding.
The key is an integer from 1 to 25.
This cipher rotates (either towards left or right) the letters of the alphabet (A to Z).
The encoding replaces each letter with the 1st to 25th next letter in the alphabet (wrapping Z to A).
So key 2 encrypts "HI" to "JK", but key 20 encrypts "HI" to "BC".
This simple "mono-alphabetic substitution cipher" provides almost no security, because an attacker who has the encoded message can either use frequency analysis to guess the key, or just try all 25 keys.
Caesar cipher is identical to Vigenère cipher with a key of length 1.
Also, Rot-13 is identical to Caesar cipher with key 13.
Related tasks
Rot-13
Substitution Cipher
Vigenère Cipher/Cryptanalysis
| #SequenceL | SequenceL | import <Utilities/Sequence.sl>;
import <Utilities/Conversion.sl>;
lowerAlphabet := "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
upperAlphabet := "abcdefghijklmnopqrstuvwxyz";
caesarEncrypt(ch, key) :=
let
correctAlphabet :=
lowerAlphabet when some(ch = lowerAlphabet)
else
upperAlphabet;
index := Sequence::firstIndexOf(correctAlphabet, ch);
newIndex := (index + key - 1) mod 26 + 1;
in
ch when not(some(ch = lowerAlphabet) or some(ch = upperAlphabet))
else
correctAlphabet[newIndex];
caesarDecrypt(ch, key) := caesarEncrypt(ch, 26 - key);
main(args(2)) :=
let
key := Conversion::stringToInt(args[2]);
encrypted := caesarEncrypt(args[1], key);
decrypted := caesarDecrypt(encrypted, key);
in
"Input: \t" ++ args[1] ++ "\n" ++
"Encrypted:\t" ++ encrypted ++ "\n" ++
"Decrypted:\t" ++ decrypted; |
http://rosettacode.org/wiki/Box_the_compass | Box the compass | There be many a land lubber that knows naught of the pirate ways and gives direction by degree!
They know not how to box the compass!
Task description
Create a function that takes a heading in degrees and returns the correct 32-point compass heading.
Use the function to print and display a table of Index, Compass point, and Degree; rather like the corresponding columns from, the first table of the wikipedia article, but use only the following 33 headings as input:
[0.0, 16.87, 16.88, 33.75, 50.62, 50.63, 67.5, 84.37, 84.38, 101.25, 118.12, 118.13, 135.0, 151.87, 151.88, 168.75, 185.62, 185.63, 202.5, 219.37, 219.38, 236.25, 253.12, 253.13, 270.0, 286.87, 286.88, 303.75, 320.62, 320.63, 337.5, 354.37, 354.38]. (They should give the same order of points but are spread throughout the ranges of acceptance).
Notes;
The headings and indices can be calculated from this pseudocode:
for i in 0..32 inclusive:
heading = i * 11.25
case i %3:
if 1: heading += 5.62; break
if 2: heading -= 5.62; break
end
index = ( i mod 32) + 1
The column of indices can be thought of as an enumeration of the thirty two cardinal points (see talk page)..
| #11l | 11l | V majors = ‘north east south west’.split(‘ ’)
majors *= 2
V quarter1 = ‘N,N by E,N-NE,NE by N,NE,NE by E,E-NE,E by N’.split(‘,’)
V quarter2 = quarter1.map(p -> p.replace(‘NE’, ‘EN’))
F degrees2compasspoint(=d)
d = (d % 360) + 360 / 64
V majorindex = Int(d / 90)
V minorindex = Int((d % 90 * 4) I/ 45)
V p1 = :majors[majorindex]
V p2 = :majors[majorindex + 1]
[String] q
I p1 C (‘north’, ‘south’)
q = :quarter1
E
q = :quarter2
R q[minorindex].replace(‘N’, p1).replace(‘E’, p2).capitalize()
:start:
L(i) 33
V d = i * 11.25
S i % 3
1
d += 5.62
2
d -= 5.62
V n = i % 32 + 1
print(‘#2.0 #<18 #4.2°’.format(n, degrees2compasspoint(d), d)) |
http://rosettacode.org/wiki/Bitmap/Histogram | Bitmap/Histogram | Extend the basic bitmap storage defined on this page to support dealing with image histograms. The image histogram contains for each luminance the count of image pixels having this luminance. Choosing a histogram representation take care about the data type used for the counts. It must have range of at least 0..NxM, where N is the image width and M is the image height.
Test task
Histogram is useful for many image processing operations. As an example, use it to convert an image into black and white art. The method works as follows:
Convert image to grayscale;
Compute the histogram
Find the median: defined as the luminance such that the image has an approximately equal number of pixels with lesser and greater luminance.
Replace each pixel of luminance lesser than the median to black, and others to white.
Use read/write ppm file, and grayscale image solutions.
| #C | C | typedef unsigned int histogram_t;
typedef histogram_t *histogram;
#define GET_LUM(IMG, X, Y) ( (IMG)->buf[ (Y) * (IMG)->width + (X)][0] )
histogram get_histogram(grayimage im);
luminance histogram_median(histogram h); |
http://rosettacode.org/wiki/Bitmap/Histogram | Bitmap/Histogram | Extend the basic bitmap storage defined on this page to support dealing with image histograms. The image histogram contains for each luminance the count of image pixels having this luminance. Choosing a histogram representation take care about the data type used for the counts. It must have range of at least 0..NxM, where N is the image width and M is the image height.
Test task
Histogram is useful for many image processing operations. As an example, use it to convert an image into black and white art. The method works as follows:
Convert image to grayscale;
Compute the histogram
Find the median: defined as the luminance such that the image has an approximately equal number of pixels with lesser and greater luminance.
Replace each pixel of luminance lesser than the median to black, and others to white.
Use read/write ppm file, and grayscale image solutions.
| #Common_Lisp | Common Lisp | (defpackage #:histogram
(:use #:cl
#:opticl))
(in-package #:histogram)
(defun color->gray-image (image)
(check-type image 8-bit-rgb-image)
(let ((gray-image (with-image-bounds (height width) image
(make-8-bit-gray-image height width :initial-element 0))))
(do-pixels (i j) image
(multiple-value-bind (r g b) (pixel image i j)
(let ((gray (+ (* 0.2126 r) (* 0.7152 g) (* 0.0722 b))))
(setf (pixel gray-image i j) (round gray)))))
gray-image))
(defun make-histogram (image)
(check-type image 8-bit-gray-image)
(let ((histogram (make-array 256 :element-type 'fixnum :initial-element 0)))
(do-pixels (i j) image
(incf (aref histogram (pixel image i j))))
histogram))
(defun find-median (histogram)
(loop with num-pixels = (loop for count across histogram sum count)
with half = (/ num-pixels 2)
for count across histogram
for i from 0
sum count into acc
when (>= acc half)
return i))
(defun gray->black&white-image (image)
(check-type image 8-bit-gray-image)
(let* ((histogram (make-histogram image))
(median (find-median histogram))
(bw-image (with-image-bounds (height width) image
(make-1-bit-gray-image height width :initial-element 0))))
(do-pixels (i j) image
(setf (pixel bw-image i j) (if (<= (pixel image i j) median) 1 0)))
bw-image))
(defun main ()
(let* ((image (read-jpeg-file "lenna.jpg"))
(bw-image (gray->black&white-image (color->gray-image image))))
(write-pbm-file "lenna-bw.pbm" bw-image))) |
http://rosettacode.org/wiki/Bitwise_operations | Bitwise operations |
Basic Data Operation
This is a basic data operation. It represents a fundamental action on a basic data type.
You may see other such operations in the Basic Data Operations category, or:
Integer Operations
Arithmetic |
Comparison
Boolean Operations
Bitwise |
Logical
String Operations
Concatenation |
Interpolation |
Comparison |
Matching
Memory Operations
Pointers & references |
Addresses
Task
Write a routine to perform a bitwise AND, OR, and XOR on two integers, a bitwise NOT on the first integer, a left shift, right shift, right arithmetic shift, left rotate, and right rotate.
All shifts and rotates should be done on the first integer with a shift/rotate amount of the second integer.
If any operation is not available in your language, note it.
| #360_Assembly | 360 Assembly | * Bitwise operations 15/02/2017
BITWISE CSECT
USING BITWISE,R13
B 72(R15)
DC 17F'0'
STM R14,R12,12(R13)
ST R13,4(R15)
ST R15,8(R13)
LR R13,R15
L R1,A
XDECO R1,PG
MVC OP,=CL7'A='
XPRNT OP,L'OP+L'PG
L R1,B
XDECO R1,PG
MVC OP,=CL7'B='
XPRNT OP,L'OP+L'PG
* And
L R1,A
N R1,B
XDECO R1,PG
MVC OP,=C'A AND B'
XPRNT OP,L'OP+L'PG
* Or
L R1,A
O R1,B
XDECO R1,PG
MVC OP,=C'A OR B'
XPRNT OP,L'OP+L'PG
* Xor
L R1,A
X R1,B
XDECO R1,PG
MVC OP,=C'A XOR B'
XPRNT OP,L'OP+L'PG
* Not
L R1,A
X R1,=X'FFFFFFFF' not (by xor -1)
XDECO R1,PG
MVC OP,=CL7'NOT A'
XPRNT OP,L'OP+L'PG
*
MVC A,=X'80000008' a=-2147483640 (-2^31+8)
L R1,A
XDECO R1,PG
MVC OP,=CL7'A='
XPRNT OP,L'OP+L'PG
* shift right arithmetic (on 31 bits)
L R1,A
SRA R1,3
XDECO R1,PG
MVC OP,=C'A SRA 3'
XPRNT OP,L'OP+L'PG
* shift left arithmetic (on 31 bits)
L R1,A
SLA R1,3
XDECO R1,PG
MVC OP,=C'A SLA 3'
XPRNT OP,L'OP+L'PG
* shift right logical (on 32 bits)
L R1,A
SRL R1,3
XDECO R1,PG
MVC OP,=C'A SRL 3'
XPRNT OP,L'OP+L'PG
* shift left logical (on 32 bits)
L R1,A
SLL R1,3
XDECO R1,PG
MVC OP,=C'A SLL 3'
XPRNT OP,L'OP+L'PG
*
RETURN L R13,4(0,R13)
LM R14,R12,12(R13)
XR R15,R15
BR R14
A DC F'21'
B DC F'3'
OP DS CL7
PG DS CL12
YREGS
END BITWISE |
http://rosettacode.org/wiki/Bitmap/Midpoint_circle_algorithm | Bitmap/Midpoint circle algorithm | Task
Using the data storage type defined on this page for raster images,
write an implementation of the midpoint circle algorithm (also known as Bresenham's circle algorithm).
(definition on Wikipedia).
| #Action.21 | Action! | INCLUDE "H6:RGBCIRCL.ACT" ;from task Midpoint circle algorithm
RGB black,yellow,violet,blue
PROC DrawImage(RgbImage POINTER img BYTE x,y)
RGB POINTER ptr
BYTE i,j
ptr=img.data
FOR j=0 TO img.h-1
DO
FOR i=0 TO img.w-1
DO
IF RgbEqual(ptr,yellow) THEN
Color=1
ELSEIF RgbEqual(ptr,violet) THEN
Color=2
ELSEIF RgbEqual(ptr,blue) THEN
Color=3
ELSE
Color=0
FI
Plot(x+i,y+j)
ptr==+RGBSIZE
OD
OD
RETURN
PROC Main()
RgbImage img
BYTE CH=$02FC,width=[81],height=[51],st=[3]
BYTE ARRAY ptr(12393)
BYTE n
INT x,y
RGB POINTER col
Graphics(7+16)
SetColor(0,13,12) ;yellow
SetColor(1,4,8) ;violet
SetColor(2,8,6) ;blue
SetColor(4,0,0) ;black
RgbBlack(black)
RgbYellow(yellow)
RgbViolet(violet)
RgbBlue(blue)
InitRgbImage(img,width,height,ptr)
FillRgbImage(img,black)
FOR n=0 TO height/st
DO
IF n MOD 3=0 THEN col=yellow
ELSEIF n MOD 3=1 THEN col=violet
ELSE col=blue FI
RgbCircle(img,width/2,height/2,st*n,col)
OD
DrawImage(img,(160-width)/2,(96-height)/2)
DO UNTIL CH#$FF OD
CH=$FF
RETURN |
http://rosettacode.org/wiki/Bitmap/Midpoint_circle_algorithm | Bitmap/Midpoint circle algorithm | Task
Using the data storage type defined on this page for raster images,
write an implementation of the midpoint circle algorithm (also known as Bresenham's circle algorithm).
(definition on Wikipedia).
| #Ada | Ada | procedure Circle
( Picture : in out Image;
Center : Point;
Radius : Natural;
Color : Pixel
) is
F : Integer := 1 - Radius;
ddF_X : Integer := 0;
ddF_Y : Integer := -2 * Radius;
X : Integer := 0;
Y : Integer := Radius;
begin
Picture (Center.X, Center.Y + Radius) := Color;
Picture (Center.X, Center.Y - Radius) := Color;
Picture (Center.X + Radius, Center.Y) := Color;
Picture (Center.X - Radius, Center.Y) := Color;
while X < Y loop
if F >= 0 then
Y := Y - 1;
ddF_Y := ddF_Y + 2;
F := F + ddF_Y;
end if;
X := X + 1;
ddF_X := ddF_X + 2;
F := F + ddF_X + 1;
Picture (Center.X + X, Center.Y + Y) := Color;
Picture (Center.X - X, Center.Y + Y) := Color;
Picture (Center.X + X, Center.Y - Y) := Color;
Picture (Center.X - X, Center.Y - Y) := Color;
Picture (Center.X + Y, Center.Y + X) := Color;
Picture (Center.X - Y, Center.Y + X) := Color;
Picture (Center.X + Y, Center.Y - X) := Color;
Picture (Center.X - Y, Center.Y - X) := Color;
end loop;
end Circle; |
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