advent19-intcode/README.md

Intcode machine defined in adventofcode 2019

# Advent Of Code 2019 Intcode Emulator

## Why module?

Since Advent Of Code seems to require same intcode computer over and over again, this module is for those who did not have a chance to implement it themselves on previous tasks but who would still love to work on future tasks.

I have integrated it into my own solution - it seems that it works well :)

## Usage

Typical usage
```javascript
const emulator = require('adventofcode-2019-intcode')

// Raw program which is normally provided as input data of the task
const raw = '................'

// Parse provided program
const soft = emulator.parseProgram(raw)

// Initialize registers
const reg = emulator.createRegisters()

// Customizable execution index (optional)
// If not provided, it will be 0
const index = 0

// Some input array (first input at index 0)
// If additional input will be requested, run will be halted
// with exit code NEED_INPUT
// One can use custom index to continue program by providing
// additional inputs.
const inputs = [0, 1, 2]

const result = emulator.run(soft, reg, inputs, p)

// emulator.run also accepts 5th parameter (boolean) which can enable printing every command it executes
```

Result is an object which may contain following keys:
* exitCode - reason for exiting (one of emulator.exitCodes)
* pos - current execution index
* registers - current state of registers
* data - current state of memory/program
* output - single output value whenever output command is reached OR array of all output values when program terminates

**Important:** Note that even though emulator returns updated data and registers as a result - it also modifies both by reference. Therefor if you need data and arguments not to be changed - you must clone them. Simplest (yet dirty) way to do it is to JSON serialize and un-serialize :)

## State of emulator

It should be completely operational. Emulator version corresponds to task number of Advent Of Code 2019 and is backwards compatible.

There is no test coverage for now - sry.

Had an idea to make opcodes configurable - maybe later :) Currently every opcode is simply hard-coded.

This module is basically a copy-paste of quick and dirty solution used for the task.

___
HF & GL