Split intcode-processor to it's own library, made day 2 work with it

2019/intcode-processor/go.mod

@@ -1,3 +0,0 @@
-module git.bullercodeworks.com/brian/adventofcode/intcode-processor
-
-go 1.13

2019/intcode-processor/processor.go

@@ -1,10 +1,28 @@
-package intcode
+package intcodeprocessor
 
-import "fmt"
+import (
+	"errors"
+	"fmt"
+)
+
+const (
+	OP_ADD = 1
+	OP_MLT = 2
+	OP_EXT = 99
+)
+
+const (
+	RET_ERR = iota - 1
+	RET_OK
+	RET_DONE
+)
 
 type Program struct {
 	code []int
 	ptr  int
+
+	state int
+	error error
 }
 
 func NewProgram(prog []int) *Program {
@@ -14,6 +32,90 @@ func NewProgram(prog []int) *Program {
 	return p
 }
 
-func (p *Program) CodeString() string {
-	return fmt.Sprintf("%v", p.code)
+func (p *Program) State() int {
+	return p.state
+}
+
+func (p *Program) Error() error {
+	return p.error
+}
+
+func (p *Program) Run() int {
+	for {
+		p.state = p.Step()
+		switch p.state {
+		case RET_ERR:
+			return RET_ERR
+		case RET_DONE:
+			return RET_DONE
+		}
+	}
+}
+
+func (p *Program) Step() int {
+	if len(p.code) < p.ptr {
+		p.error = errors.New("Pointer Exception")
+		return RET_ERR
+	}
+	switch p.readNext() {
+	case OP_ADD:
+		p.add(p.readNextThree())
+		if p.error != nil {
+			return RET_ERR
+		}
+		return RET_OK
+	case OP_MLT:
+		p.mult(p.readNextThree())
+		if p.error != nil {
+			return RET_ERR
+		}
+		return RET_OK
+	case OP_EXT:
+		return RET_DONE
+	}
+	return RET_ERR
+}
+
+func (p *Program) GetProgramValueAt(idx int) int {
+	return p.code[idx]
+}
+
+func (p *Program) SetProgramValueAt(idx, val int) {
+	p.code[idx] = val
+}
+
+func (p *Program) readNext() int {
+	if len(p.code) <= p.ptr {
+		p.error = errors.New("Pointer Exception")
+	}
+	p.ptr++
+	return p.code[p.ptr-1]
+}
+
+func (p *Program) readNextTwo() (int, int) {
+	return p.readNext(), p.readNext()
+}
+
+func (p *Program) readNextThree() (int, int, int) {
+	return p.readNext(), p.readNext(), p.readNext()
+}
+
+func (p *Program) add(a1, a2, dest int) {
+	p.code[dest] = p.code[a1] + p.code[a2]
+}
+
+func (p *Program) mult(a1, a2, dest int) {
+	p.code[dest] = p.code[a1] * p.code[a2]
+}
+
+func (p Program) String() string {
+	var ret string
+	for k := range p.code {
+		if k == p.ptr {
+			ret = fmt.Sprintf("%s [%d]", ret, p.code[k])
+		} else {
+			ret = fmt.Sprintf("%s %d", ret, p.code[k])
+		}
+	}
+	return ret
 }

2019/intcode-processor/processor_test.go

@@ -1,4 +1,4 @@
-package intcode
+package intcodeprocessor
 
 import (
 	"fmt"