IntCode Processor Input/Output changes

For day 5, ask the user for input

2019/intcode-processor/processor.go

@@ -6,11 +6,6 @@ import (
 	"math"
 )
 
-const (
-	MODE_POS = iota
-	MODE_IMM
-)
-
 const (
 	OP_ADD = 1
 	OP_MLT = 2
@@ -23,6 +18,11 @@ const (
 	OP_EXT = 99
 )
 
+const (
+	MODE_POS = iota
+	MODE_IMM
+)
+
 const (
 	RET_ERR = iota - 1
 	RET_OK
@@ -36,15 +36,17 @@ type Program struct {
 	state int
 	error error
 
-	input  chan int
-	output chan int
+	waitingForInput  bool
+	input            chan int
+	waitingForOutput bool
+	output           chan int
 }
 
 func NewProgram(prog []int) *Program {
 	p := new(Program)
 	p.code = make([]int, len(prog))
-	p.input = make(chan int, 2)
-	p.output = make(chan int, 2)
+	p.input = make(chan int)
+	p.output = make(chan int)
 	copy(p.code, prog)
 	return p
 }
@@ -157,6 +159,14 @@ func (p *Program) SetProgramValueAt(idx, val int) {
 	p.code[idx] = val
 }
 
+func (p *Program) NeedsInput() bool {
+	return p.waitingForInput
+}
+
+func (p *Program) NeedsOutput() bool {
+	return p.waitingForOutput
+}
+
 func (p *Program) opCode(intcode int) int {
 	return intcode % 100
 }
@@ -188,12 +198,15 @@ func (p *Program) get(mode, v int) int {
 	return v
 }
 
-func (p *Program) Input() chan int {
-	return p.input
+func (p *Program) Input(v int) {
+	p.input <- v
+	p.waitingForInput = false
 }
 
-func (p *Program) Output() chan int {
-	return p.output
+func (p *Program) Output() int {
+	v := <-p.output
+	p.waitingForOutput = false
+	return v
 }
 
 func (p *Program) opAdd(intcode, a1, a2, dest int) {
@@ -220,12 +233,15 @@ func (p *Program) opInp(intcode, dest int) {
 		p.error = errors.New("Invalid Destination Mode")
 		p.state = RET_ERR
 	}
+	p.waitingForInput = true
 	p.code[dest] = <-p.input
+	p.waitingForInput = false
 }
 
 func (p *Program) opOut(intcode, val int) {
 	valmd := p.paramMode(intcode, 0)
 	ret := p.get(valmd, val)
+	p.waitingForOutput = true
 	p.output <- ret
 }