Brainfuck

Brainfuck.swift is a flexible Brainfuck interpreter in Swift 3.1.

It comes with unit tests and tracing / debuging functions.

It also comes with Brainloller and Braincopter readers.

Brainfuck commands:

>	Move pointer right
<	Move pointer left
+	Increment memory under pointer
-	Decrement memory under pointer
.	Output value under pointer
,	Input value and store it under pointer
[	Jump past matching ] if value under pointer is 0
]	Jump back to matching [ if value under pointer is nonzero

Here are several ways to use Brainfuck.swift, given the following program:

let helloWorld = "++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--------.>+.>."

1. Simple call

let b = try! Brainfuck(helloWorld)
let result = try! b.run()

Result: Hello World!\n

2. Use optional parameters

let b = try! Brainfuck(helloWorld, userInput: "", dataSize: 32)
let result = try! b.run()

Result: Hello World!\n

3. Call step by step

do {
    let b = try Brainfuck(helloWorld)
    
    while b.canRun() {
        if let byte = try b.step() {
            print(byte)
        }
    }
} catch let e {
    print(e)
}

Output:

72
101
108
108
111
32
87
111
114
108
100
33
10

4. Print state at each step

do {
    let b = try Brainfuck("++++++[>++++++<-]>.") // 6x6 == 0x24 == '$'
    
    while b.canRun() {
        print("-------------------------------------------------------------")
        b.printStep()
        b.printInstructions()
        b.printData(upToIndex: 10)
        
        if let putByte = try b.step() {
            print(" PUT: " + String(format: "%02X", putByte))
        }
    }
    
    print("-------------------------------------------------------------")
    b.printExecutionSummary()
    
} catch let e {
    print(e)
}

Output:

...
-------------------------------------------------------------
STEP: 73
PROG: ++++++[>++++++<-]>.
                       ^ 17
DATA: 00 24 00 00 00 00 00 00 00 00 00
      ^^ 0
-------------------------------------------------------------
STEP: 74
PROG: ++++++[>++++++<-]>.
                        ^ 18
DATA: 00 24 00 00 00 00 00 00 00 00 00
         ^^ 1
 PUT: 24
-------------------------------------------------------------
SUMMARY: program stopped after 75 step(s) with output:
    HEX: 24
    STR: $

5. Brainloller

Brainloller stores Brainfuck commands in image pixels.

Example with this code:

let bl = try! Brainloller(imagePath: "/tmp/fibonacci.png")
let s1 = bl.brainfuck()
print(s1)

let bf = try! Brainfuck(s1)
let s2 = try! bf.run()
print(s2)

Input (magnified 10x):

Brainloller commands:

red        (255,0,0)	>
darkred    (128,0,0)	<
green      (0,255,0)	+
darkgreen  (0,128,0)	-
blue       (0,0,255)	.
darkblue   (0,0,128)	,
yellow     (255,255,0)	[
darkyellow (128,128,0)	]
cyan       (0,255,255)	rotates the IP 90° clockwise
darkcyan   (0,128,128)	rotates the IP 90° counter-clockwise
others     n/a          nop

Output (s1) is Brainfuck instructions:

++++++++++++++++++++++++++++++++++++++++++++>++++++++++++++++++++++++++++++++>++++++++++++++++>>+<<[>>>>++++++++++<<[->+>-[>+>>]>[+[-<+>]>+>>]<<<<<<]>[<+>-]>[-]>>>++++++++++<[->-[>+>>]>[+[-<+>]>+>>]<<<<<]>[-]>>[++++++++++++++++++++++++++++++++++++++++++++++++.[-]]<[++++++++++++++++++++++++++++++++++++++++++++++++.[-]]<<<++++++++++++++++++++++++++++++++++++++++++++++++.[-]<<<<<<<.>.>>[>>+<<-]>[>+<<+>-]>[<+>-]<<<-]<<++...

Output (s2) is Brainfuck code exection output:

1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 121, 98, 219, ...

6. Braincopter

Braincopter is a variant of Brainloller in which commands are stored in pixels of any color.

The commands are retrieved from pixels this way:

command = (65536 * R + 256 * G + B) % 11

0	>
1	<
2	+
3	-
4	.
5	,
6	[
7	]
8	rotate IP to the right
9	rotate IP to the left
10	nop

Example with this code:

    let path = "/tmp/braincopter2.png"
    let bl = try! Braincopter(imagePath: path)
    let (_, s1) = bl.brainfuck()
    print(s1)
    
    let bf = try! Brainfuck(s1)
    let s2 = try! bf.run()
    print(s2)

Input (magnified 10x):

Output (s1) is Brainfuck instructions:

>++++++++++[<++++++++++>-]>>>>>>>>>>>>>>>>++++[>++++<-]>[<<<<<<<++>+++>++++>++++++>+++++++>+++++++>++++>-]<++<+++++<++++++++++<+++++++++<++++++<<<<<<<<<<<<<[>+>+>[-]>>>>[-]>[-]<<<<<<<[>>>>>>+>+<<<<<<<-]>>>>>>[<<<<<<+>>>>>>-]+>---[<->[-]]<[>>>>>>.>.>..<<<<<<<<<<<<+<<[-]>>>>>>-]<<<<<[>>>>>+>+<<<<<<-]>>>>>[<<<<<+>>>>>-]+>-----[<->[-]]<[>>>>>>>>>>.<.<..<<<<<<<<<<<<+<[-]>>>>>-]<+>[-]>[-]>[-]<<<[>+>+>+<<<-]>[<+>-]+>----------[<->[-]]<[<<+>[-]>-]>[-]>[-]<<<<[>>+>+>+<<<<-]>>[<<+>>-]+>----------[<->[-]]<[<<<+>[-]>>-][-]>[-]<<<<<[>>>>+>+<<<<<-]>>>>[<<<<+>>>>-]+>[<->[-]]<[[-]>[-]<<<<[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<[>++++++++[<++++++>-]<.-.[-]][-]>[-]<<<[>>+>+<<<-]>>>[<<<+>>>-]<[>++++++++[<++++++>-]<.[-]][-]>[-]<<[>+>+<<-]>>[<<+>>-]++++++++[<++++++>-]<.[-]]>>>>.<<<<<<<<<<<-]

Output (s2) is Brainfuck code exection output:

1 2 Fizz 4 Buzz Fizz 7 8 Fizz Buzz 11 Fizz 13 14 FizzBuzz 16 17 Fizz 19 Buzz Fizz 22 23 Fizz Buzz 26 Fizz 28 29 FizzBuzz 31 32 Fizz 34 Buzz Fizz 37 38 Fizz Buzz 41 Fizz 43 44 FizzBuzz 46 47 Fizz 49 Buzz Fizz 52 53 Fizz Buzz 56 Fizz 58 59 FizzBuzz 61 62 Fizz 64 Buzz Fizz 67 68 Fizz Buzz 71 Fizz 73 74 FizzBuzz 76 77 Fizz 79 Buzz Fizz 82 83 Fizz Buzz 86 Fizz 88 89 FizzBuzz 91 92 Fizz 94 Buzz Fizz 97 98 Fizz Buz