// Part 1 about an Interpreter for the Brainf*** language

//========================================================

// representation of Bf memory 

type Mem = Map[Int, Int]

// (1) Write a function that takes a file name as argument and

// and requests the corresponding file from disk. It Returns the

// content of the file as a String. If the file does not exists,

// the function should Return the empty string.

import io.Source

import scala.util._

//def load_bff(name: String) : String = ...

// (2) Complete the functions for safely reading  

// and writing brainf*** memory. Safely read should

// Return the value stored in the Map for a given memory

// pointer, provided it exists; otherwise it Returns 0. The

// writing function generates a new Map with the

// same data, except at the given memory pointer the

// value v is stored.

//def sread(mem: Mem, mp: Int) : Int = ...

//def write(mem: Mem, mp: Int, v: Int) : Mem = ...

// (3) Implement the two jumping instructions in the 

// brainf*** language. In jumpRight, given a program and 

// a program counter move the program counter to the right 

// until after the *matching* ]-command. Similarly, 

// jumpLeft implements the move to the left to just after

// the *matching* [-command.

//def jumpRight(prog: String, pc: Int, level: Int) : Int = ...

//def jumpLeft(prog: String, pc: Int, level: Int) : Int = ...

// testcases

//jumpRight("""--[..+>--],>,++""", 3, 0)         // => 10

//jumpLeft("""--[..+>--],>,++""", 8, 0)          // => 3

//jumpRight("""--[..[+>]--],>,++""", 3, 0)       // => 12

//jumpRight("""--[..[[-]+>[.]]--],>,++""", 3, 0) // => 18

//jumpRight("""--[..[[-]+>[.]]--,>,++""", 3, 0)  // => 22 (outside)

//jumpLeft("""[******]***""", 7, 0)              // => -1 (outside)

// (4) Complete the compute function that interprets (runs) a brainf***

// program: the arguments are a program (represented as a string), a program 

// counter, a memory counter and a brainf*** memory. It Returns the

// memory at the stage when the execution of the brainf*** program

// finishes. The interpretation finishes once the program counter

// pc is pointing to something outside the program string.

// If the pc points to a character inside the program, the pc, 

// memory pointer and memory need to be updated according to 

// rules of the brainf*** language. Then, recursively, the compute 

// function continues with the command at the new program

// counter. 

//

// Implement the run function that calls compute with the program

// counter and memory counter set to 0.

//def compute(prog: String, pc: Int, mp: Int, mem: Mem) : Mem = ...

//def run(prog: String, m: Mem = Map()) = ...

/*

// some sample bf-programs collected from the Internet

//=====================================================

// first some contrived (small) programs

// clears the 0-cell

run("[-]", Map(0 -> 100))    // Map will be 0 -> 0

// copies content of the 0-cell to 1-cell

run("[->+<]", Map(0 -> 10))  // Map will be 0 -> 0, 1 -> 10

// copies content of the 0-cell to 2-cell and 4-cell

run("[>>+>>+<<<<-]", Map(0 -> 42))

// prints out numbers 0 to 9

run("""+++++[->++++++++++<]>--<+++[->>++++++++++<<]>>++<<----------[+>.>.<+<]""")

// some more "useful" programs

// hello world program 1

run("""++++++++[>++++[>++>+++>+++>+<<<<-]>+>+>->>+[<]<-]>>.>---.+++++++

       ..+++.>>.<-.<.+++.------.--------.>>+.>++.""")

// hello world program 2

run("""++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>+

      +.<<+++++++++++++++.>.+++.------.--------.>+.>.""")

// draws the Sierpinski triangle

run("""++++++++[>+>++++<<-]>++>>+<[-[>>+<<-]+>>]>+[-<<<[

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

      ]>.>+[>>]>+]""")

run(load_bff("sierpinski.bf"))

//fibonacci numbers below 100

run("""+++++++++++

      >+>>>>++++++++++++++++++++++++++++++++++++++++++++

      >++++++++++++++++++++++++++++++++<<<<<<[>[>>>>>>+>

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

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

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

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

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

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

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

      [-]]<<[>>+>+<<<-]>>>[<<<+>>>-]<<[<+>-]>[<+>-]<<<-]""")

//outputs the square numbers up to 10000

run("""++++[>+++++<-]>[<+++++>-]+<+[

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

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

    <<[>>>>>[>>>[-]+++++++++<[>-<-]+++++++++>[-[<->-]+[<<<]]<[>+<-]>]<<-]<<-]""")

//collatz numbers (needs a number to be typed in)

run(""">,[[----------[

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

      ++++++[>------<-]>--[>>[->>>>]+>+[<<<<]>-],<]>]>>>++>+>>[

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

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

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

      ]>>+[[-]++++++>>>>]<<<<[[<++++++++>-]<.[-]<[-]<[-]<]<,]""")

// infinite collatz (never stops)

run(""">>+>+<[[->>[>>]>>>[>>]+[<<]<<<[<<]>[>[>>]>>+>[>>]<+<[<<]<<<[<

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

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

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

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

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

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

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

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

      >>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>-[<->>+<-[<+>

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

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

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

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

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

      [<+>-[<+>-[<+>-[<[-]>>[-]+>+<<-]]]]]]]]]]<[>+<-]+>>]<<[<<]>>]""")

// a Mandelbrot set generator in brainf*** written by Erik Bosman

// (http://esoteric.sange.fi/brainfuck/utils/mandelbrot/)

run(load_bff("mandelbrot.bf"))

// a benchmark program (counts down from 'Z' to 'A')

val b1 = """>++[<+++++++++++++>-]<[[>+>+<<-]>[<+>-]++++++++

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

            ++++++++[>++++++++++[>++++++++++[>++++++++++[>+

            +++++++++[-]<-]<-]<-]<-]<-]<-]<-]++++++++++."""

def time_needed[T](n: Int, code: => T) = {

  val start = System.nanoTime()

  for (i <- 0 until n) code

  val end = System.nanoTime()

  (end - start)/(n * 1.0e9)

}

time_needed(1, run(b1))

*/