Initial version of a brainfuck interpreter

brainfuck.go

@@ -0,0 +1,113 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"io/ioutil"
+	"os"
+)
+
+const (
+	MEM_MAX = 3000000
+	MEM_STD = 30000
+)
+
+type Machine struct {
+	array  []byte
+	ptr    int
+	reader *bufio.Reader
+}
+
+// Returns a new machine with standard memory size
+func New() *Machine {
+	bytes := make([]byte, MEM_STD)
+	return &Machine{
+		array:  bytes,
+		ptr:    0,
+		reader: bufio.NewReader(os.Stdin),
+	}
+}
+
+// Implements '>'
+func (m *Machine) PtrIncr() {
+	if m.ptr >= len(m.array)-1 {
+		m.array = append(m.array, 0)
+	}
+	m.ptr += 1
+	if m.ptr > MEM_MAX {
+		panic("Memory overflow")
+	}
+}
+
+// Implements '<'
+func (m *Machine) PtrDecr() {
+	if m.ptr == 0 {
+		panic("Memory underflow")
+	}
+	m.ptr -= 1
+}
+
+// Implements '+'
+func (m *Machine) ByteIncr() {
+	if m.ptr > len(m.array)-1 {
+		fmt.Printf("Memory overflow, ptr=%d\n", m.ptr)
+	}
+	m.array[m.ptr] += 1
+}
+
+// Implements '-'
+func (m *Machine) ByteDecr() {
+	m.array[m.ptr] -= 1
+}
+
+// Implements the '.' command
+func (m *Machine) Output() {
+	fmt.Printf("%c", m.array[m.ptr])
+}
+
+// Implements the ',' command
+func (m *Machine) Input() {
+	input, err := m.reader.ReadByte()
+	if err != nil {
+		m.array[m.ptr] = 0
+	} else {
+		m.array[m.ptr] = input
+	}
+}
+
+// Run the whole program specified by input
+func (m *Machine) Run(input []byte) {
+	// execute the program
+	loop := -1
+	discard := false
+	for i := 0; i < len(input); i++ {
+		instr := input[i]
+		if discard && instr != ']' {
+			continue
+		} else if instr == '[' {
+			loop = i
+			if m.array[m.ptr] == 0 {
+				discard = true
+			}
+		} else if instr == ']' {
+			if m.array[m.ptr] != 0 {
+				i = loop
+			} else {
+				discard = false
+			}
+		} else if instr == '>' {
+			m.PtrIncr()
+		} else if instr == '<' {
+			m.PtrDecr()
+		} else if instr == '+' {
+			m.ByteIncr()
+		} else if instr == '-' {
+			m.ByteDecr()
+		} else if instr == '.' {
+			m.Output()
+		} else if instr == ',' {
+			m.Input()
+		}
+
+	}
+}

examples/99botles.bf

@@ -0,0 +1,60 @@
+99 Bottles of Beer in Urban Mueller's BrainF*** (The actual
+name is impolite)
+
+by Ben Olmstead
+
+ANSI C interpreter available on the internet; due to
+constraints in comments the address below needs to have the
+stuff in parenthesis replaced with the appropriate symbol:
+
+http://www(dot)cats(dash)eye(dot)com/cet/soft/lang/bf/
+
+Believe it or not this language is indeed Turing complete!
+Combines the speed of BASIC with the ease of INTERCAL and
+the readability of an IOCCC entry!
+
+>+++++++++[<+++++++++++>-]<[>[-]>[-]<<[>+>+<<-]>>[<<+>>-]>>>
+[-]<<<+++++++++<[>>>+<<[>+>[-]<<-]>[<+>-]>[<<++++++++++>>>+<
+-]<<-<-]+++++++++>[<->-]>>+>[<[-]<<+>>>-]>[-]+<<[>+>-<<-]<<<
+[>>+>+<<<-]>>>[<<<+>>>-]>[<+>-]<<-[>[-]<[-]]>>+<[>[-]<-]<+++
++++++[<++++++<++++++>>-]>>>[>+>+<<-]>>[<<+>>-]<[<<<<<.>>>>>-
+]<<<<<<.>>[-]>[-]++++[<++++++++>-]<.>++++[<++++++++>-]<++.>+
+++++[<+++++++++>-]<.><+++++..--------.-------.>>[>>+>+<<<-]>
+>>[<<<+>>>-]<[<<<<++++++++++++++.>>>>-]<<<<[-]>++++[<+++++++
++>-]<.>+++++++++[<+++++++++>-]<--.---------.>+++++++[<------
+---->-]<.>++++++[<+++++++++++>-]<.+++..+++++++++++++.>++++++
+++[<---------->-]<--.>+++++++++[<+++++++++>-]<--.-.>++++++++
+[<---------->-]<++.>++++++++[<++++++++++>-]<++++.-----------
+-.---.>+++++++[<---------->-]<+.>++++++++[<+++++++++++>-]<-.
+>++[<----------->-]<.+++++++++++..>+++++++++[<---------->-]<
+-----.---.>>>[>+>+<<-]>>[<<+>>-]<[<<<<<.>>>>>-]<<<<<<.>>>+++
++[<++++++>-]<--.>++++[<++++++++>-]<++.>+++++[<+++++++++>-]<.
+><+++++..--------.-------.>>[>>+>+<<<-]>>>[<<<+>>>-]<[<<<<++
+++++++++++++.>>>>-]<<<<[-]>++++[<++++++++>-]<.>+++++++++[<++
++++++++>-]<--.---------.>+++++++[<---------->-]<.>++++++[<++
++++++++++>-]<.+++..+++++++++++++.>++++++++++[<---------->-]<
+-.---.>+++++++[<++++++++++>-]<++++.+++++++++++++.++++++++++.
+------.>+++++++[<---------->-]<+.>++++++++[<++++++++++>-]<-.
+-.---------.>+++++++[<---------->-]<+.>+++++++[<++++++++++>-
+]<--.+++++++++++.++++++++.---------.>++++++++[<---------->-]
+<++.>+++++[<+++++++++++++>-]<.+++++++++++++.----------.>++++
++++[<---------->-]<++.>++++++++[<++++++++++>-]<.>+++[<----->
+-]<.>+++[<++++++>-]<..>+++++++++[<--------->-]<--.>+++++++[<
+++++++++++>-]<+++.+++++++++++.>++++++++[<----------->-]<++++
+.>+++++[<+++++++++++++>-]<.>+++[<++++++>-]<-.---.++++++.----
+---.----------.>++++++++[<----------->-]<+.---.[-]<<<->[-]>[
+-]<<[>+>+<<-]>>[<<+>>-]>>>[-]<<<+++++++++<[>>>+<<[>+>[-]<<-]
+>[<+>-]>[<<++++++++++>>>+<-]<<-<-]+++++++++>[<->-]>>+>[<[-]<
+<+>>>-]>[-]+<<[>+>-<<-]<<<[>>+>+<<<-]>>>[<<<+>>>-]<>>[<+>-]<
+<-[>[-]<[-]]>>+<[>[-]<-]<++++++++[<++++++<++++++>>-]>>>[>+>+
+<<-]>>[<<+>>-]<[<<<<<.>>>>>-]<<<<<<.>>[-]>[-]++++[<++++++++>
+-]<.>++++[<++++++++>-]<++.>+++++[<+++++++++>-]<.><+++++..---
+-----.-------.>>[>>+>+<<<-]>>>[<<<+>>>-]<[<<<<++++++++++++++
+.>>>>-]<<<<[-]>++++[<++++++++>-]<.>+++++++++[<+++++++++>-]<-
+-.---------.>+++++++[<---------->-]<.>++++++[<+++++++++++>-]
+<.+++..+++++++++++++.>++++++++[<---------->-]<--.>+++++++++[
+<+++++++++>-]<--.-.>++++++++[<---------->-]<++.>++++++++[<++
+++++++++>-]<++++.------------.---.>+++++++[<---------->-]<+.
+>++++++++[<+++++++++++>-]<-.>++[<----------->-]<.+++++++++++
+..>+++++++++[<---------->-]<-----.---.+++.---.[-]<<<]
+

examples/HELLOBF2.BF

@@ -0,0 +1 @@
+>+++++++++[<++++++++>-]<.>+++++++[<++++>-]<+.+++++++..+++.[-]>++++++++[<++++>-]<.#>+++++++++++[<+++++>-]<.>++++++++[<+++>-]<.+++.------.--------.[-]>++++++++[<++++>-]<+.[-]++++++++++.

examples/SORT.BF

@@ -0,0 +1,6 @@
+Here is a Brainf*** program that bubblesorts its input and spits it out:
+>>>>>,+[>>>,+]<<<[<<<
+[>>>[-<<<-<+>[>]>>]<<<[<]>>
+[>>>+<<<-]<[>+>>>+<<<<-]
+<<]>>>[-.[-]]>>>[>>>]<<<]
+

examples/cat.bf

@@ -0,0 +1 @@
+,[.,]

examples/hello.bf

@@ -0,0 +1,21 @@
++++++ +++++             initialize counter (cell #0) to 10
+[                       use loop to set the next four cells to 70/100/30/10
+    > +++++ ++              add  7 to cell #1
+    > +++++ +++++           add 10 to cell #2 
+    > +++                   add  3 to cell #3
+    > +                     add  1 to cell #4
+    <<<< -                  decrement counter (cell #0)
+]                   
+> ++ .                  print 'H'
+> + .                   print 'e'
++++++ ++ .              print 'l'
+.                       print 'l'
++++ .                   print 'o'
+> ++ .                  print ' '
+<< +++++ +++++ +++++ .  print 'W'
+> .                     print 'o'
++++ .                   print 'r'
+----- - .               print 'l'
+----- --- .             print 'd'
+> + .                   print '!'
+> .                     print '\n'

examples/prime.bf

@@ -0,0 +1,224 @@
+compute prime numbers
+to use type the max number then push Alt 1 0
+===================================================================
+======================== OUTPUT STRING ============================
+===================================================================
+>++++++++[<++++++++>-]<++++++++++++++++.[-]
+>++++++++++[<++++++++++>-]<++++++++++++++.[-]
+>++++++++++[<++++++++++>-]<+++++.[-]
+>++++++++++[<++++++++++>-]<+++++++++.[-]
+>++++++++++[<++++++++++>-]<+.[-]
+>++++++++++[<++++++++++>-]<+++++++++++++++.[-]
+>+++++[<+++++>-]<+++++++.[-]
+>++++++++++[<++++++++++>-]<+++++++++++++++++.[-]
+>++++++++++[<++++++++++>-]<++++++++++++.[-]
+>+++++[<+++++>-]<+++++++.[-]
+>++++++++++[<++++++++++>-]<++++++++++++++++.[-]
+>++++++++++[<++++++++++>-]<+++++++++++.[-]
+>+++++++[<+++++++>-]<+++++++++.[-]
+>+++++[<+++++>-]<+++++++.[-]
+
+===================================================================
+======================== INPUT NUMBER  ============================
+===================================================================
++                          cont=1
+[
+ -                         cont=0
+ >,
+ ======SUB10======
+ ----------
+ 
+ [                         not 10
+  <+>                      cont=1
+  =====SUB38======
+  ----------
+  ----------
+  ----------
+  --------
+
+  >
+  =====MUL10=======
+  [>+>+<<-]>>[<<+>>-]<     dup
+
+  >>>+++++++++
+  [
+   <<<
+   [>+>+<<-]>>[<<+>>-]<    dup
+   [<<+>>-]
+   >>-
+  ]
+  <<<[-]<
+  ======RMOVE1======
+  <
+  [>+<-]
+ ]
+ <
+]
+>>[<<+>>-]<<
+
+===================================================================
+======================= PROCESS NUMBER  ===========================
+===================================================================
+
+==== ==== ==== ====
+numd numu teid teiu
+==== ==== ==== ====
+
+>+<-
+[
+ >+
+ ======DUP======
+ [>+>+<<-]>>[<<+>>-]<
+
+ >+<--
+
+ >>>>>>>>+<<<<<<<<   isprime=1
+
+ [
+  >+
+
+  <-
+
+  =====DUP3=====
+  <[>>>+>+<<<<-]>>>>[<<<<+>>>>-]<<<
+
+  =====DUP2=====
+  >[>>+>+<<<-]>>>[<<<+>>>-]<<< <
+
+
+  >>>
+
+
+  ====DIVIDES=======
+  [>+>+<<-]>>[<<+>>-]<   DUP i=div
+  
+  <<
+  [
+    >>>>>+               bool=1
+    <<<
+    [>+>+<<-]>>[<<+>>-]< DUP
+    [>>[-]<<-]           IF i THEN bool=0
+    >>
+    [                    IF i=0
+      <<<<
+      [>+>+<<-]>>[<<+>>-]< i=div
+      >>>
+      -                  bool=0
+    ]
+    <<<
+    -                    DEC i
+    <<
+    -
+  ]
+  
+  +>>[<<[-]>>-]<<          
+  >[-]<                  CLR div
+  =====END DIVIDES====
+
+
+  [>>>>>>[-]<<<<<<-]     if divides then isprime=0
+
+
+  <<
+
+  >>[-]>[-]<<<
+ ]
+
+ >>>>>>>>
+ [
+  -
+  <<<<<<<[-]<<
+
+  [>>+>+<<<-]>>>[<<<+>>>-]<<<
+
+  >>
+
+
+
+
+  ===================================================================
+  ======================== OUTPUT NUMBER  ===========================
+  ===================================================================
+  [>+<-]>
+ 
+  [
+   ======DUP======
+   [>+>+<<-]>>[<<+>>-]<
+  
+  
+   ======MOD10====
+   >+++++++++<
+   [
+    >>>+<<              bool= 1
+    [>+>[-]<<-]         bool= ten==0
+    >[<+>-]             ten = tmp
+    >[<<++++++++++>>-]  if ten=0 ten=10
+    <<-                 dec ten     
+    <-                  dec num
+   ]
+   +++++++++            num=9
+   >[<->-]<             dec num by ten
+  
+   =======RROT======
+      [>+<-]
+   <  [>+<-]
+   <  [>+<-]
+   >>>[<<<+>>>-]
+   <
+  
+   =======DIV10========
+   >+++++++++<
+   [
+    >>>+<<                bool= 1
+    [>+>[-]<<-]           bool= ten==0
+    >[<+>-]               ten = tmp
+    >[<<++++++++++>>>+<-] if ten=0 ten=10  inc div
+    <<-                   dec ten     
+    <-                    dec num
+   ]
+   >>>>[<<<<+>>>>-]<<<<   copy div to num
+   >[-]<                  clear ten
+  
+   =======INC1=========
+   <+>
+  ]
+  
+  <
+  [
+   =======MOVER=========
+   [>+<-]
+  
+   =======ADD48========
+   +++++++[<+++++++>-]<->
+  
+   =======PUTC=======
+   <.[-]>
+  
+   ======MOVEL2========
+   >[<<+>>-]<
+  
+   <-
+  ]
+ 
+  >++++[<++++++++>-]<.[-]
+ 
+  ===================================================================
+  =========================== END FOR ===============================
+  ===================================================================
+
+
+  >>>>>>>
+ ]
+ <<<<<<<<
+
+
+
+ >[-]<
+  [-]
+ <<-
+]
+ 
+======LF========
+ 
+++++++++++.[-]
+@

examples/rot13.bf

@@ -0,0 +1,29 @@
+ 
+-,+[                         Read first character and start outer character reading loop
+    -[                       Skip forward if character is 0
+        >>++++[>++++++++<-]  Set up divisor (32) for division loop
+                               (MEMORY LAYOUT: dividend copy remainder divisor quotient zero zero)
+        <+<-[                Set up dividend (x minus 1) and enter division loop
+            >+>+>-[>>>]      Increase copy and remainder / reduce divisor / Normal case: skip forward
+            <[[>+<-]>>+>]    Special case: move remainder back to divisor and increase quotient
+            <<<<<-           Decrement dividend
+        ]                    End division loop
+    ]>>>[-]+                 End skip loop; zero former divisor and reuse space for a flag
+    >--[-[<->+++[-]]]<[         Zero that flag unless quotient was 2 or 3; zero quotient; check flag
+        ++++++++++++<[       If flag then set up divisor (13) for second division loop
+                               (MEMORY LAYOUT: zero copy dividend divisor remainder quotient zero zero)
+            >-[>+>>]         Reduce divisor; Normal case: increase remainder
+            >[+[<+>-]>+>>]   Special case: increase remainder / move it back to divisor / increase quotient
+            <<<<<-           Decrease dividend
+        ]                    End division loop
+        >>[<+>-]             Add remainder back to divisor to get a useful 13
+        >[                   Skip forward if quotient was 0
+            -[               Decrement quotient and skip forward if quotient was 1
+                -<<[-]>>     Zero quotient and divisor if quotient was 2
+            ]<<[<<->>-]>>    Zero divisor and subtract 13 from copy if quotient was 1
+        ]<<[<<+>>-]          Zero divisor and add 13 to copy if quotient was 0
+    ]                        End outer skip loop (jump to here if ((character minus 1)/32) was not 2 or 3)
+    <[-]                     Clear remainder from first division if second division was skipped
+    <.[-]                    Output ROT13ed character from copy and clear it
+    <-,+                     Read next character
+]                            End character reading loop

examples/test

@@ -0,0 +1,2 @@
+++++++++++[>+++++++>++++++++++>+++>+<<<<-]>++.>+.+++++++..+++.>++.<<+++++++++++++++.>.+++.------.--
+------.>+.>.

examples/test2

@@ -0,0 +1,2 @@
++++[>+++++<-]>[>+>+++>+>++>+++++>++<[++<]>---]>.-.[>++>+<<--]>--.--.+.>>>++.<<.<------.+.+++++.>>-
+.<++++.<--.>>>.<<---.<.-.-.>+.[+++++.---<]>>[.--.]<<.<+.++.++>+++[.<][.]<++.

gofuck/main.go

@@ -0,0 +1,22 @@
+package main
+
+import "brainfuck"
+
+func main() {
+	m := New()
+	instructions := make([]byte, 0)
+
+	// read in the instructions
+	if len(os.Args) < 2 {
+		panic("No input given")
+	}
+
+	file, err := os.Open(os.Args[1])
+	reader := bufio.NewReader(file)
+	instructions, err = ioutil.ReadAll(reader)
+	if err != nil {
+		panic(err)
+	}
+
+	m.Run(instructions)
+}