Add brainfuck script in go

.gitignore

@@ -0,0 +1 @@
+brainfuck

brainfuck.go

@@ -0,0 +1,227 @@
+package main
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/fatih/color"
+	"github.com/forestgiant/sliceutil"
+	flag "github.com/spf13/pflag"
+)
+
+func main() {
+	bf := BrainfuckEmulator{}
+	var err error
+	err = bf.New()
+	if err != nil {
+		if strings.HasSuffix(err.Error(), "::ignore") {
+			return
+		}
+		panic(err)
+	}
+	err = bf.Run()
+	if err != nil {
+		if strings.HasSuffix(err.Error(), "::ignore") {
+			return
+		}
+		panic(err)
+	}
+}
+
+// BrainfuckEmulator is used to emulate brainfuck.
+type BrainfuckEmulator struct {
+	code      string
+	pairs     [][]int
+	memory    []int
+	execution int
+	pointer   int
+	debug     bool
+	filename  string
+}
+
+// New instance of BrainfuckEmulator.
+func (bf *BrainfuckEmulator) New() error {
+	var err error
+	err = bf.args()
+	if err != nil {
+		return err
+	}
+	err = bf.readScript(bf.filename)
+	if err != nil {
+		return err
+	}
+	err = bf.getBracketPairs()
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (bf *BrainfuckEmulator) args() error {
+	debugptr := flag.BoolP("debug", "d", false, "Enable debug mode")
+	flag.Parse()
+	args := flag.Args()
+	if len(args) == 1 {
+		bf.filename = args[0]
+		bf.debug = *debugptr
+	} else {
+		fmt.Fprintln(os.Stdout, "Brainfuck help")
+		fmt.Fprintln(os.Stdout, "usage: brainfuck <filename>")
+		flag.PrintDefaults()
+		return errors.New("bf: invalid arguments ::ignore")
+	}
+	return nil
+}
+
+func (bf *BrainfuckEmulator) fancyoutput() {
+	for i := 0; i < len(bf.memory); i++ {
+		if bf.pointer == i {
+			color.Set(color.FgRed)
+			fmt.Fprintf(os.Stdout, fmt.Sprint(bf.memory[i]))
+			color.Unset()
+		} else {
+			fmt.Fprintf(os.Stdout, fmt.Sprint(bf.memory[i]))
+		}
+		if i < len(bf.memory)-1 {
+			fmt.Fprintf(os.Stdout, ",")
+		}
+	}
+	fmt.Fprintln(os.Stdout, "")
+	for i := 0; i < len(bf.code); i++ {
+		if bf.execution == i {
+			color.Set(color.FgRed)
+			fmt.Fprintf(os.Stdout, string(bf.code[i]))
+			color.Unset()
+		} else {
+			fmt.Fprintf(os.Stdout, string(bf.code[i]))
+		}
+	}
+	fmt.Fprintln(os.Stdout, "")
+}
+
+// Run the brainfuck program.
+func (bf *BrainfuckEmulator) Run() error {
+	bf.pointer = 0
+	bf.execution = 0
+	bf.memory = []int{0}
+
+	for true {
+		if bf.debug {
+			bf.fancyoutput()
+		}
+
+		if bf.execution >= len(bf.code) {
+			break
+		}
+		switch bf.code[bf.execution] {
+		case '+':
+			bf.memory[bf.pointer]++
+			if bf.memory[bf.pointer] == 256 {
+				bf.memory[bf.pointer] = 0
+			}
+		case '-':
+			bf.memory[bf.pointer]--
+			if bf.memory[bf.pointer] == -1 {
+				bf.memory[bf.pointer] = 255
+			}
+		case '>':
+			bf.pointer++
+			if len(bf.memory) <= bf.pointer {
+				bf.memory = append(bf.memory, 0)
+			}
+		case '<':
+			bf.pointer--
+			if bf.pointer < 0 {
+				fmt.Fprintln(os.Stdout, "Memory underflow: pointer can't be less than 0")
+				return errors.New("bf: memory underflow ::ignore")
+			}
+		case '[':
+			if bf.memory[bf.pointer] == 0 {
+				for i := 0; i < len(bf.pairs[0]); i++ {
+					if bf.pairs[0][i] == bf.execution {
+						bf.execution = bf.pairs[1][i]
+						break
+					}
+				}
+			}
+		case ']':
+			if bf.memory[bf.pointer] != 0 {
+				for i := 0; i < len(bf.pairs[1]); i++ {
+					if bf.pairs[1][i] == bf.execution {
+						bf.execution = bf.pairs[0][i]
+						break
+					}
+				}
+			}
+		case '@':
+			bf.pointer = 0
+		case '$':
+			bf.fancyoutput()
+		case ',':
+			char := make([]byte, 1)
+			os.Stdin.Read(char)
+			bf.memory[bf.pointer] = int(char[0])
+		case '.':
+			b := byte(bf.memory[bf.pointer])
+			os.Stdout.Write([]byte{b})
+		}
+		bf.execution++
+	}
+	return nil
+}
+
+func (bf *BrainfuckEmulator) readScript(filename string) error {
+	filebuffer, err := ioutil.ReadFile(filename)
+	if err != nil {
+		if strings.HasSuffix(err.Error(), "no such file or directory") {
+			fmt.Fprintln(os.Stdout, "IO Error: no such file or directory")
+			return errors.New("bf: file missing ::ignore")
+		}
+		return err
+	}
+	inputdata := string(filebuffer)
+	data := bufio.NewScanner(strings.NewReader(inputdata))
+	data.Split(bufio.ScanRunes)
+
+	allowed := []string{"+", "-", "<", ">", "[", "]", ",", ".", "@"}
+	final := ""
+	for data.Scan() {
+		if sliceutil.Contains(allowed, data.Text()) {
+			final += data.Text()
+		}
+	}
+
+	bf.code = final
+	return nil
+}
+
+func (bf *BrainfuckEmulator) getBracketPairs() error {
+	pairs := [][]int{{}, {}}
+	temp := []int{}
+	var err error
+
+	for i := 0; i < len(bf.code); i++ {
+		if bf.code[i] == '[' {
+			temp = append(temp, i)
+		} else if bf.code[i] == ']' {
+			if len(temp) > 0 {
+				pairs[0] = append(pairs[0], temp[len(temp)-1])
+				pairs[1] = append(pairs[1], i)
+				temp = temp[:len(temp)-1]
+			} else {
+				fmt.Fprintln(os.Stdout, "Syntax error: missing opening bracket")
+				return errors.New("bf: missing opening bracket ::ignore")
+			}
+		}
+	}
+	if len(temp) != 0 {
+		fmt.Fprintln(os.Stdout, "Syntax error: spare opening bracket")
+		return errors.New("bf: sqare opening brackets ::ignore")
+	}
+	bf.pairs = pairs
+	return err
+}

build

@@ -0,0 +1,3 @@
+#!/bin/bash
+go build -o brainfuck
+sudo cp ./brainfuck /usr/bin/brainfuck