BF 習作, string <-> byteがださい. fizzbazzも動いた.

gistfile1.txt

package main

import "fmt"


type BF struct {
    pc int
    ptr int
    mem [3000]byte
    code [1000]byte
    stack [1000]int
    last int
}

func (self* BF) dump(n int) {
    fmt.Printf("pc/ptr = %d/%d ", self.pc, self.ptr)
    for i := 0; i< n; i++ {
        fmt.Printf("%3d:", self.mem[i])
    }
    fmt.Printf("\n")
}

func (self* BF) push(pos int) {
    //fmt.Printf("pushing %c at %d\n", self.code[pos], pos)
    if self.last > 10 {
        panic("stack limit exceeded")
    }
    self.stack[self.last]=pos
    self.last++
}

func (self* BF) peek() int {
    if self.last < 0 {
        panic("peeking empty stack")
    }
    return self.stack[self.last - 1]
}

func (self* BF) pop() int {
    //fmt.Printf("popping %d at %d\n", self.stack[self.last], self.last)
    if self.last < 1 {
        panic("popping empty stack")
    }
    self.last--
    v := self.stack[self.last]
    self.stack[self.last] = 0
    return v
}

func (self* BF) seek(from int) int {

    for i := from ; i < len(self.code); i++ {
        switch self.code[i] {
        case ']':
            return i
        case '[':
            i = self.seek(i+1) + 1//skip to
        }
    }
    panic("none match pair of []")
}

func (self* BF) exec(op byte) {

    switch op {
        case ' ':
            self.pc++
        case '\n':
            self.pc++
        case '>':
            self.ptr++
            self.pc++
        case '<':
            self.ptr--
            self.pc++
        case '+':
            self.mem[self.ptr]++
            self.pc++
        case '-':
            self.mem[self.ptr]--
            self.pc++
        case '.':
            fmt.Printf("%c", self.mem[self.ptr]) //ascii code!
            self.pc++
        case '[':
            if self.mem[self.ptr] != 0 {
                self.push(self.pc)
                self.pc++
            }else{
                self.pc = self.seek(self.pc + 1)
                self.pc++
            }
        case ']':
            self.pc = self.pop()
    }
}

func (self* BF) run(source string) {
    var op byte

    for i := 0; i < len(source); i++ {
        self.code[i] = source[i]
    }
    for self.pc < len(source) {
        //self.dump(10)
        op = self.code[self.pc]
        self.exec(op)
    }
}

const helloworld = "+++++++++[>++++++++>+++++++++++>+++++<<<-]>.>++.+++++++..+++.>-.------------.<++++++++.--------.+++.------.--------.>+."

const fizzbuzz = "++++++[->++++> >+>+>-<<<<<]>[<++++>" +
 ">+++>++++> >+++>+++++>+++++> > > > > >++> >++<<<<<<<<<<<<<<-]<++++>+++" +
 ">-->+++>-> >--->++> > >+++++[->++>++<<]<<<<<<<<<<[->-" +
 "[> > > > > > >]>[<+++>.>.> > > >..> > >+<]<<<<<-[> > > >]>[<+" +
 "++++>.>.>..> > >+<]> > > >+<-[<<<]<[[-<<+> >]> > >+>+<<<<<" +
 "<[-> >+>+>-<<<<]<]>>[[-]<]>[> > >[>.<<.<<<]<[.<<<<]>]>.<<<<" +
 "<<<<<<<]"

func main() {

    bf := new(BF)
    bf.run(fizzbuzz)

    //bf.dump()
}