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