feat(flight-finder): implement milestone M1 - domain model and skill contract

skills/flight-finder/node_modules/restructure/src/Array.js

@@ -0,0 +1,106 @@
+import {Base} from './Base.js';
+import {Number as NumberT} from './Number.js';
+import * as utils from './utils.js';
+
+class ArrayT extends Base {
+  constructor(type, length, lengthType = 'count') {
+    super();
+    this.type = type;
+    this.length = length;
+    this.lengthType = lengthType;
+  }
+
+  decode(stream, parent) {
+    let length;
+    const { pos } = stream;
+
+    const res = [];
+    let ctx = parent;
+
+    if (this.length != null) {
+      length = utils.resolveLength(this.length, stream, parent);
+    }
+
+    if (this.length instanceof NumberT) {
+      // define hidden properties
+      Object.defineProperties(res, {
+        parent:         { value: parent },
+        _startOffset:   { value: pos },
+        _currentOffset: { value: 0, writable: true },
+        _length:        { value: length }
+      });
+
+      ctx = res;
+    }
+
+    if ((length == null) || (this.lengthType === 'bytes')) {
+      const target = (length != null) ?
+        stream.pos + length
+      : (parent != null ? parent._length : undefined) ?
+        parent._startOffset + parent._length
+      :
+        stream.length;
+
+      while (stream.pos < target) {
+        res.push(this.type.decode(stream, ctx));
+      }
+
+    } else {
+      for (let i = 0, end = length; i < end; i++) {
+        res.push(this.type.decode(stream, ctx));
+      }
+    }
+
+    return res;
+  }
+
+  size(array, ctx, includePointers = true) {
+    if (!array) {
+      return this.type.size(null, ctx) * utils.resolveLength(this.length, null, ctx);
+    }
+
+    let size = 0;
+    if (this.length instanceof NumberT) {
+      size += this.length.size();
+      ctx = {parent: ctx, pointerSize: 0};
+    }
+
+    for (let item of array) {
+      size += this.type.size(item, ctx);
+    }
+
+    if (ctx && includePointers && this.length instanceof NumberT) {
+      size += ctx.pointerSize;
+    }
+    
+    return size;
+  }
+
+  encode(stream, array, parent) {
+    let ctx = parent;
+    if (this.length instanceof NumberT) {
+      ctx = {
+        pointers: [],
+        startOffset: stream.pos,
+        parent
+      };
+
+      ctx.pointerOffset = stream.pos + this.size(array, ctx, false);
+      this.length.encode(stream, array.length);
+    }
+
+    for (let item of array) {
+      this.type.encode(stream, item, ctx);
+    }
+
+    if (this.length instanceof NumberT) {
+      let i = 0;
+      while (i < ctx.pointers.length) {
+        const ptr = ctx.pointers[i++];
+        ptr.type.encode(stream, ptr.val, ptr.parent);
+      }
+    }
+  }
+}
+
+export {ArrayT as Array};

skills/flight-finder/node_modules/restructure/src/Base.js

@@ -0,0 +1,17 @@
+import {DecodeStream} from './DecodeStream.js';
+import {EncodeStream} from './EncodeStream.js';
+
+export class Base {
+  fromBuffer(buffer) {
+    let stream = new DecodeStream(buffer);
+    return this.decode(stream);
+  }
+
+  toBuffer(value) {
+    let size = this.size(value);
+    let buffer = new Uint8Array(size);
+    let stream = new EncodeStream(buffer);
+    this.encode(stream, value);
+    return buffer;
+  }
+}

skills/flight-finder/node_modules/restructure/src/Bitfield.js

@@ -0,0 +1,39 @@
+import {Base} from './Base.js';
+
+export class Bitfield extends Base {
+  constructor(type, flags = []) {
+    super();
+    this.type = type;
+    this.flags = flags;
+  }
+
+  decode(stream) {
+    const val = this.type.decode(stream);
+
+    const res = {};
+    for (let i = 0; i < this.flags.length; i++) {
+      const flag = this.flags[i];
+      if (flag != null) {
+        res[flag] = !!(val & (1 << i));
+      }
+    }
+
+    return res;
+  }
+
+  size() {
+    return this.type.size();
+  }
+
+  encode(stream, keys) {
+    let val = 0;
+    for (let i = 0; i < this.flags.length; i++) {
+      const flag = this.flags[i];
+      if (flag != null) {
+        if (keys[flag]) { val |= (1 << i); }
+      }
+    }
+
+    return this.type.encode(stream, val);
+  }
+}

skills/flight-finder/node_modules/restructure/src/Boolean.js

@@ -0,0 +1,22 @@
+import {Base} from './Base.js';
+
+export class BooleanT extends Base {
+  constructor(type) {
+    super();
+    this.type = type;
+  }
+
+  decode(stream, parent) {
+    return !!this.type.decode(stream, parent);
+  }
+
+  size(val, parent) {
+    return this.type.size(val, parent);
+  }
+
+  encode(stream, val, parent) {
+    return this.type.encode(stream, +val, parent);
+  }
+}
+
+export {BooleanT as Boolean};

skills/flight-finder/node_modules/restructure/src/Buffer.js

@@ -0,0 +1,38 @@
+import {Base} from './Base.js';
+import {Number as NumberT} from './Number.js';
+import * as utils from './utils.js';
+
+export class BufferT extends Base {
+  constructor(length) {
+    super();
+    this.length = length;
+  }
+  
+  decode(stream, parent) {
+    const length = utils.resolveLength(this.length, stream, parent);
+    return stream.readBuffer(length);
+  }
+
+  size(val, parent) {
+    if (!val) {
+      return utils.resolveLength(this.length, null, parent);
+    }
+
+    let len = val.length;
+    if (this.length instanceof NumberT) {
+      len += this.length.size();
+    }
+
+    return len;
+  }
+
+  encode(stream, buf, parent) {
+    if (this.length instanceof NumberT) {
+      this.length.encode(stream, buf.length);
+    }
+
+    return stream.writeBuffer(buf);
+  }
+}
+
+export {BufferT as Buffer};

skills/flight-finder/node_modules/restructure/src/DecodeStream.js

@@ -0,0 +1,85 @@
+// Node back-compat.
+const ENCODING_MAPPING = {
+  utf16le: 'utf-16le',
+  ucs2: 'utf-16le',
+  utf16be: 'utf-16be'
+}
+
+export class DecodeStream {
+  constructor(buffer) {
+    this.buffer = buffer;
+    this.view = new DataView(buffer.buffer, buffer.byteOffset, buffer.byteLength);
+    this.pos = 0;
+    this.length = this.buffer.length;
+  }
+
+  readString(length, encoding = 'ascii') {
+    encoding = ENCODING_MAPPING[encoding] || encoding;
+
+    let buf = this.readBuffer(length);
+    try {
+      let decoder = new TextDecoder(encoding);
+      return decoder.decode(buf);
+    } catch (err) {
+      return buf;
+    }
+  }
+
+  readBuffer(length) {
+    return this.buffer.slice(this.pos, (this.pos += length));
+  }
+
+  readUInt24BE() {
+    return (this.readUInt16BE() << 8) + this.readUInt8();
+  }
+
+  readUInt24LE() {
+    return this.readUInt16LE() + (this.readUInt8() << 16);
+  }
+
+  readInt24BE() {
+    return (this.readInt16BE() << 8) + this.readUInt8();
+  }
+
+  readInt24LE() {
+    return this.readUInt16LE() + (this.readInt8() << 16);
+  }
+}
+
+DecodeStream.TYPES = {
+  UInt8: 1,
+  UInt16: 2,
+  UInt24: 3,
+  UInt32: 4,
+  Int8: 1,
+  Int16: 2,
+  Int24: 3,
+  Int32: 4,
+  Float: 4,
+  Double: 8
+};
+
+for (let key of Object.getOwnPropertyNames(DataView.prototype)) {
+  if (key.slice(0, 3) === 'get') {
+    let type = key.slice(3).replace('Ui', 'UI');
+    if (type === 'Float32') {
+      type = 'Float';
+    } else if (type === 'Float64') {
+      type = 'Double';
+    }
+    let bytes = DecodeStream.TYPES[type];
+    DecodeStream.prototype['read' + type + (bytes === 1 ? '' : 'BE')] = function () {
+      const ret = this.view[key](this.pos, false);
+      this.pos += bytes;
+      return ret;
+    };
+
+    if (bytes !== 1) {
+      DecodeStream.prototype['read' + type + 'LE'] = function () {
+        const ret = this.view[key](this.pos, true);
+        this.pos += bytes;
+        return ret;
+      };
+    }
+  }
+}

skills/flight-finder/node_modules/restructure/src/EncodeStream.js

@@ -0,0 +1,129 @@
+import {DecodeStream} from './DecodeStream.js';
+
+const textEncoder = new TextEncoder();
+const isBigEndian = new Uint8Array(new Uint16Array([0x1234]).buffer)[0] == 0x12;
+
+export class EncodeStream {
+  constructor(buffer) {
+    this.buffer = buffer;
+    this.view = new DataView(this.buffer.buffer, this.buffer.byteOffset, this.buffer.byteLength);
+    this.pos = 0;
+  }
+
+  writeBuffer(buffer) {
+    this.buffer.set(buffer, this.pos);
+    this.pos += buffer.length;
+  }
+
+  writeString(string, encoding = 'ascii') {
+    let buf;
+    switch (encoding) {
+      case 'utf16le':
+      case 'utf16-le':
+      case 'ucs2': // node treats this the same as utf16.
+        buf = stringToUtf16(string, isBigEndian);
+        break;
+
+      case 'utf16be':
+      case 'utf16-be':
+        buf = stringToUtf16(string, !isBigEndian);
+        break;
+
+      case 'utf8':
+        buf = textEncoder.encode(string);
+        break;
+
+      case 'ascii':
+        buf = stringToAscii(string);
+        break;
+
+      default:
+        throw new Error(`Unsupported encoding: ${encoding}`);
+    }
+
+    this.writeBuffer(buf);
+  }
+
+  writeUInt24BE(val) {
+    this.buffer[this.pos++] = (val >>> 16) & 0xff;
+    this.buffer[this.pos++] = (val >>> 8) & 0xff;
+    this.buffer[this.pos++] = val & 0xff;
+  }
+
+  writeUInt24LE(val) {
+    this.buffer[this.pos++] = val & 0xff;
+    this.buffer[this.pos++] = (val >>> 8) & 0xff;
+    this.buffer[this.pos++] = (val >>> 16) & 0xff;
+  }
+
+  writeInt24BE(val) {
+    if (val >= 0) {
+      this.writeUInt24BE(val);
+    } else {
+      this.writeUInt24BE(val + 0xffffff + 1);
+    }
+  }
+
+  writeInt24LE(val) {
+    if (val >= 0) {
+      this.writeUInt24LE(val);
+    } else {
+      this.writeUInt24LE(val + 0xffffff + 1);
+    }
+  }
+
+  fill(val, length) {
+    if (length < this.buffer.length) {
+      this.buffer.fill(val, this.pos, this.pos + length);
+      this.pos += length;
+    } else {
+      const buf = new Uint8Array(length);
+      buf.fill(val);
+      this.writeBuffer(buf);
+    }
+  }
+}
+
+function stringToUtf16(string, swap) {
+  let buf = new Uint16Array(string.length);
+  for (let i = 0; i < string.length; i++) {
+    let code = string.charCodeAt(i);
+    if (swap) {
+      code = (code >> 8) | ((code & 0xff) << 8);
+    }
+    buf[i] = code;
+  }
+  return new Uint8Array(buf.buffer);
+}
+
+function stringToAscii(string) {
+  let buf = new Uint8Array(string.length);
+  for (let i = 0; i < string.length; i++) {
+    // Match node.js behavior - encoding allows 8-bit rather than 7-bit.
+    buf[i] = string.charCodeAt(i);
+  }
+  return buf;
+}
+
+for (let key of Object.getOwnPropertyNames(DataView.prototype)) {
+  if (key.slice(0, 3) === 'set') {
+    let type = key.slice(3).replace('Ui', 'UI');
+    if (type === 'Float32') {
+      type = 'Float';
+    } else if (type === 'Float64') {
+      type = 'Double';
+    }
+    let bytes = DecodeStream.TYPES[type];
+    EncodeStream.prototype['write' + type + (bytes === 1 ? '' : 'BE')] = function (value) {
+      this.view[key](this.pos, value, false);
+      this.pos += bytes;
+    };
+
+    if (bytes !== 1) {
+      EncodeStream.prototype['write' + type + 'LE'] = function (value) {
+        this.view[key](this.pos, value, true);
+        this.pos += bytes;
+      };
+    }
+  }
+}

skills/flight-finder/node_modules/restructure/src/Enum.js

@@ -0,0 +1,27 @@
+import {Base} from './Base.js';
+
+export class Enum extends Base {
+  constructor(type, options = []) {
+    super();
+    this.type = type;
+    this.options = options;
+  }
+  
+  decode(stream) {
+    const index = this.type.decode(stream);
+    return this.options[index] || index;
+  }
+
+  size() {
+    return this.type.size();
+  }
+
+  encode(stream, val) {
+    const index = this.options.indexOf(val);
+    if (index === -1) {
+      throw new Error(`Unknown option in enum: ${val}`);
+    }
+
+    return this.type.encode(stream, index);
+  }
+}

skills/flight-finder/node_modules/restructure/src/LazyArray.js

@@ -0,0 +1,74 @@
+import {Array as ArrayT} from './Array.js';
+import {Number as NumberT} from './Number.js';
+import * as utils from './utils.js';
+
+export class LazyArray extends ArrayT {
+  decode(stream, parent) {
+    const { pos } = stream;
+    const length = utils.resolveLength(this.length, stream, parent);
+
+    if (this.length instanceof NumberT) {
+      parent = {
+        parent,
+        _startOffset: pos,
+        _currentOffset: 0,
+        _length: length
+      };
+    }
+
+    const res = new LazyArrayValue(this.type, length, stream, parent);
+
+    stream.pos += length * this.type.size(null, parent);
+    return res;
+  }
+
+  size(val, ctx) {
+    if (val instanceof LazyArrayValue) {
+      val = val.toArray();
+    }
+
+    return super.size(val, ctx);
+  }
+
+  encode(stream, val, ctx) {
+    if (val instanceof LazyArrayValue) {
+      val = val.toArray();
+    }
+
+    return super.encode(stream, val, ctx);
+  }
+}
+
+class LazyArrayValue {
+  constructor(type, length, stream, ctx) {
+    this.type = type;
+    this.length = length;
+    this.stream = stream;
+    this.ctx = ctx;
+    this.base = this.stream.pos;
+    this.items = [];
+  }
+
+  get(index) {
+    if ((index < 0) || (index >= this.length)) {
+      return undefined;
+    }
+
+    if (this.items[index] == null) {
+      const { pos } = this.stream;
+      this.stream.pos = this.base + (this.type.size(null, this.ctx) * index);
+      this.items[index] = this.type.decode(this.stream, this.ctx);
+      this.stream.pos = pos;
+    }
+
+    return this.items[index];
+  }
+
+  toArray() {
+    const result = [];
+    for (let i = 0, end = this.length; i < end; i++) {
+      result.push(this.get(i));
+    }
+    return result;
+  }
+}

skills/flight-finder/node_modules/restructure/src/Number.js

@@ -0,0 +1,77 @@
+import {DecodeStream} from './DecodeStream.js';
+import {Base} from './Base.js';
+
+class NumberT extends Base {
+  constructor(type, endian = 'BE') {
+    super();
+    this.type = type;
+    this.endian = endian;
+    this.fn = this.type;
+    if (this.type[this.type.length - 1] !== '8') {
+      this.fn += this.endian;
+    }
+  }
+
+  size() {
+    return DecodeStream.TYPES[this.type];
+  }
+
+  decode(stream) {
+    return stream[`read${this.fn}`]();
+  }
+
+  encode(stream, val) {
+    return stream[`write${this.fn}`](val);
+  }
+}
+
+export {NumberT as Number};
+
+export const uint8 = new NumberT('UInt8');
+export const uint16be = new NumberT('UInt16', 'BE');
+export const uint16 = uint16be;
+export const uint16le = new NumberT('UInt16', 'LE');
+export const uint24be = new NumberT('UInt24', 'BE');
+export const uint24 = uint24be;
+export const uint24le = new NumberT('UInt24', 'LE');
+export const uint32be = new NumberT('UInt32', 'BE');
+export const uint32 = uint32be;
+export const uint32le = new NumberT('UInt32', 'LE');
+export const int8 = new NumberT('Int8');
+export const int16be = new NumberT('Int16', 'BE');
+export const int16 = int16be;
+export const int16le = new NumberT('Int16', 'LE');
+export const int24be = new NumberT('Int24', 'BE');
+export const int24 = int24be;
+export const int24le = new NumberT('Int24', 'LE');
+export const int32be = new NumberT('Int32', 'BE');
+export const int32 = int32be;
+export const int32le = new NumberT('Int32', 'LE');
+export const floatbe = new NumberT('Float', 'BE');
+export const float = floatbe;
+export const floatle = new NumberT('Float', 'LE');
+export const doublebe = new NumberT('Double', 'BE');
+export const double = doublebe;
+export const doublele = new NumberT('Double', 'LE');
+
+export class Fixed extends NumberT {
+  constructor(size, endian, fracBits = size >> 1) {
+    super(`Int${size}`, endian);
+    this._point = 1 << fracBits;
+  }
+
+  decode(stream) {
+    return super.decode(stream) / this._point;
+  }
+
+  encode(stream, val) {
+    return super.encode(stream, (val * this._point) | 0);
+  }
+}
+
+export const fixed16be = new Fixed(16, 'BE');
+export const fixed16 = fixed16be;
+export const fixed16le = new Fixed(16, 'LE');
+export const fixed32be = new Fixed(32, 'BE');
+export const fixed32 = fixed32be;
+export const fixed32le = new Fixed(32, 'LE');

skills/flight-finder/node_modules/restructure/src/Optional.js

@@ -0,0 +1,44 @@
+import {Base} from './Base.js';
+
+export class Optional extends Base {
+  constructor(type, condition = true) {
+    super();
+    this.type = type;
+    this.condition = condition;
+  }
+
+  decode(stream, parent) {
+    let { condition } = this;
+    if (typeof condition === 'function') {
+      condition = condition.call(parent, parent);
+    }
+
+    if (condition) {
+      return this.type.decode(stream, parent);
+    }
+  }
+
+  size(val, parent) {
+    let { condition } = this;
+    if (typeof condition === 'function') {
+      condition = condition.call(parent, parent);
+    }
+
+    if (condition) {
+      return this.type.size(val, parent);
+    } else {
+      return 0;
+    }
+  }
+
+  encode(stream, val, parent) {
+    let { condition } = this;
+    if (typeof condition === 'function') {
+      condition = condition.call(parent, parent);
+    }
+
+    if (condition) {
+      return this.type.encode(stream, val, parent);
+    }
+  }
+}

skills/flight-finder/node_modules/restructure/src/Pointer.js

@@ -0,0 +1,167 @@
+import * as utils from './utils.js';
+import {Base} from './Base.js';
+
+export class Pointer extends Base {
+  constructor(offsetType, type, options = {}) {
+    super();
+    this.offsetType = offsetType;
+    this.type = type;
+    this.options = options;
+    if (this.type === 'void') { this.type = null; }
+    if (this.options.type == null) { this.options.type = 'local'; }
+    if (this.options.allowNull == null) { this.options.allowNull = true; }
+    if (this.options.nullValue == null) { this.options.nullValue = 0; }
+    if (this.options.lazy == null) { this.options.lazy = false; }
+    if (this.options.relativeTo) {
+      if (typeof this.options.relativeTo !== 'function') {
+        throw new Error('relativeTo option must be a function');
+      }
+      this.relativeToGetter = options.relativeTo;
+    }
+  }
+
+  decode(stream, ctx) {
+    const offset = this.offsetType.decode(stream, ctx);
+
+    // handle NULL pointers
+    if ((offset === this.options.nullValue) && this.options.allowNull) {
+      return null;
+    }
+
+    let relative;
+    switch (this.options.type) {
+      case 'local':     relative = ctx._startOffset; break;
+      case 'immediate': relative = stream.pos - this.offsetType.size(); break;
+      case 'parent':    relative = ctx.parent._startOffset; break;
+      default:
+        var c = ctx;
+        while (c.parent) {
+          c = c.parent;
+        }
+
+        relative = c._startOffset || 0;
+    }
+
+    if (this.options.relativeTo) {
+      relative += this.relativeToGetter(ctx);
+    }
+
+    const ptr = offset + relative;
+
+    if (this.type != null) {
+      let val = null;
+      const decodeValue = () => {
+        if (val != null) { return val; }
+
+        const { pos } = stream;
+        stream.pos = ptr;
+        val = this.type.decode(stream, ctx);
+        stream.pos = pos;
+        return val;
+      };
+
+      // If this is a lazy pointer, define a getter to decode only when needed.
+      // This obviously only works when the pointer is contained by a Struct.
+      if (this.options.lazy) {
+        return new utils.PropertyDescriptor({
+          get: decodeValue});
+      }
+
+      return decodeValue();
+    } else {
+      return ptr;
+    }
+  }
+
+  size(val, ctx) {
+    const parent = ctx;
+    switch (this.options.type) {
+      case 'local': case 'immediate':
+        break;
+      case 'parent':
+        ctx = ctx.parent;
+        break;
+      default: // global
+        while (ctx.parent) {
+          ctx = ctx.parent;
+        }
+    }
+
+    let { type } = this;
+    if (type == null) {
+      if (!(val instanceof VoidPointer)) {
+        throw new Error("Must be a VoidPointer");
+      }
+
+      ({ type } = val);
+      val = val.value;
+    }
+
+    if (val && ctx) {
+      // Must be written as two separate lines rather than += in case `type.size` mutates ctx.pointerSize.
+      let size = type.size(val, parent);
+      ctx.pointerSize += size;
+    }
+
+    return this.offsetType.size();
+  }
+
+  encode(stream, val, ctx) {
+    let relative;
+    const parent = ctx;
+    if ((val == null)) {
+      this.offsetType.encode(stream, this.options.nullValue);
+      return;
+    }
+
+    switch (this.options.type) {
+      case 'local':
+        relative = ctx.startOffset;
+        break;
+      case 'immediate':
+        relative = stream.pos + this.offsetType.size(val, parent);
+        break;
+      case 'parent':
+        ctx = ctx.parent;
+        relative = ctx.startOffset;
+        break;
+      default: // global
+        relative = 0;
+        while (ctx.parent) {
+          ctx = ctx.parent;
+        }
+    }
+
+    if (this.options.relativeTo) {
+      relative += this.relativeToGetter(parent.val);
+    }
+
+    this.offsetType.encode(stream, ctx.pointerOffset - relative);
+
+    let { type } = this;
+    if (type == null) {
+      if (!(val instanceof VoidPointer)) {
+        throw new Error("Must be a VoidPointer");
+      }
+
+      ({ type } = val);
+      val = val.value;
+    }
+
+    ctx.pointers.push({
+      type,
+      val,
+      parent
+    });
+
+    return ctx.pointerOffset += type.size(val, parent);
+  }
+}
+
+// A pointer whose type is determined at decode time
+export class VoidPointer {
+  constructor(type, value) {
+    this.type = type;
+    this.value = value;
+  }
+}

skills/flight-finder/node_modules/restructure/src/Reserved.js

@@ -0,0 +1,23 @@
+import {Base} from './Base.js';
+import * as utils from './utils.js';
+
+export class Reserved extends Base {
+  constructor(type, count = 1) {
+    super();
+    this.type = type;
+    this.count = count;
+  }
+  decode(stream, parent) {
+    stream.pos += this.size(null, parent);
+    return undefined;
+  }
+
+  size(data, parent) {
+    const count = utils.resolveLength(this.count, null, parent);
+    return this.type.size() * count;
+  }
+
+  encode(stream, val, parent) {
+    return stream.fill(0, this.size(val, parent));
+  }
+}

skills/flight-finder/node_modules/restructure/src/String.js

@@ -0,0 +1,155 @@
+import {Base} from './Base.js';
+import {Number as NumberT} from './Number.js';
+import * as utils from './utils.js';
+
+class StringT extends Base {
+  constructor(length, encoding = 'ascii') {
+    super();
+    this.length = length;
+    this.encoding = encoding;
+  }
+
+  decode(stream, parent) {
+    let length, pos;
+
+    let { encoding } = this;
+    if (typeof encoding === 'function') {
+      encoding = encoding.call(parent, parent) || 'ascii';
+    }
+    let width = encodingWidth(encoding);
+
+    if (this.length != null) {
+      length = utils.resolveLength(this.length, stream, parent);
+    } else {
+      let buffer;
+      ({buffer, length, pos} = stream);
+
+      while ((pos < length - width + 1) &&
+        (buffer[pos] !== 0x00 ||
+        (width === 2 && buffer[pos+1] !== 0x00)
+        )) {
+        pos += width;
+      }
+
+      length = pos - stream.pos;
+    }
+
+
+    const string = stream.readString(length, encoding);
+
+    if ((this.length == null) && (stream.pos < stream.length)) {
+      stream.pos+=width;
+    }
+
+    return string;
+  }
+
+  size(val, parent) {
+    // Use the defined value if no value was given
+    if (val === undefined || val === null) {
+      return utils.resolveLength(this.length, null, parent);
+    }
+
+    let { encoding } = this;
+    if (typeof encoding === 'function') {
+      encoding = encoding.call(parent != null ? parent.val : undefined, parent != null ? parent.val : undefined) || 'ascii';
+    }
+
+    if (encoding === 'utf16be') {
+      encoding = 'utf16le';
+    }
+
+    let size = byteLength(val, encoding);
+    if (this.length instanceof NumberT) {
+      size += this.length.size();
+    }
+
+    if ((this.length == null)) {
+      size += encodingWidth(encoding);
+    }
+
+    return size;
+  }
+
+  encode(stream, val, parent) {
+    let { encoding } = this;
+    if (typeof encoding === 'function') {
+      encoding = encoding.call(parent != null ? parent.val : undefined, parent != null ? parent.val : undefined) || 'ascii';
+    }
+
+    if (this.length instanceof NumberT) {
+      this.length.encode(stream, byteLength(val, encoding));
+    }
+
+    stream.writeString(val, encoding);
+
+    if ((this.length == null)) {
+      return encodingWidth(encoding) == 2 ?
+        stream.writeUInt16LE(0x0000) :
+        stream.writeUInt8(0x00);
+    }
+  }
+}
+
+function encodingWidth(encoding) {
+  switch(encoding) {
+    case 'ascii':
+    case 'utf8': // utf8 is a byte-based encoding for zero-term string
+      return 1;
+    case 'utf16le':
+    case 'utf16-le':
+    case 'utf-16be':
+    case 'utf-16le':
+    case 'utf16be':
+    case 'utf16-be':
+    case 'ucs2':
+      return 2;
+    default:
+      //TODO: assume all other encodings are 1-byters
+      //throw new Error('Unknown encoding ' + encoding);
+      return 1;
+  }
+}
+
+function byteLength(string, encoding) {
+  switch (encoding) {
+    case 'ascii':
+      return string.length;
+    case 'utf8':
+      let len = 0;
+      for (let i = 0; i < string.length; i++) {
+        let c = string.charCodeAt(i);
+
+        if (c >= 0xd800 && c <= 0xdbff && i < string.length - 1) {
+          let c2 = string.charCodeAt(++i);
+          if ((c2 & 0xfc00) === 0xdc00) {
+            c = ((c & 0x3ff) << 10) + (c2 & 0x3ff) + 0x10000;
+          } else {
+            // unmatched surrogate.
+            i--;
+          }
+        }
+
+        if ((c & 0xffffff80) === 0) {
+          len++;
+        } else if ((c & 0xfffff800) === 0) {
+          len += 2;
+        } else if ((c & 0xffff0000) === 0) {
+          len += 3;
+        } else if ((c & 0xffe00000) === 0) {
+          len += 4;
+        }
+      }
+      return len;
+    case 'utf16le':
+    case 'utf16-le':
+    case 'utf16be':
+    case 'utf16-be':
+    case 'ucs2':
+      return string.length * 2;
+    default:
+      throw new Error('Unknown encoding ' + encoding);
+  }
+}
+
+export {StringT as String};

skills/flight-finder/node_modules/restructure/src/Struct.js

@@ -0,0 +1,113 @@
+import {Base} from './Base.js';
+import * as utils from './utils.js';
+
+export class Struct extends Base {
+  constructor(fields = {}) {
+    super();
+    this.fields = fields;
+  }
+
+  decode(stream, parent, length = 0) {
+    const res = this._setup(stream, parent, length);
+    this._parseFields(stream, res, this.fields);
+
+    if (this.process != null) {
+      this.process.call(res, stream);
+    }
+    return res;
+  }
+
+  _setup(stream, parent, length) {
+    const res = {};
+
+    // define hidden properties
+    Object.defineProperties(res, {
+      parent:         { value: parent },
+      _startOffset:   { value: stream.pos },
+      _currentOffset: { value: 0, writable: true },
+      _length:        { value: length }
+    });
+
+    return res;
+  }
+
+  _parseFields(stream, res, fields) {
+    for (let key in fields) {
+      var val;
+      const type = fields[key];
+      if (typeof type === 'function') {
+        val = type.call(res, res);
+      } else {
+        val = type.decode(stream, res);
+      }
+
+      if (val !== undefined) {
+        if (val instanceof utils.PropertyDescriptor) {
+          Object.defineProperty(res, key, val);
+        } else {
+          res[key] = val;
+        }
+      }
+
+      res._currentOffset = stream.pos - res._startOffset;
+    }
+
+  }
+
+  size(val, parent, includePointers = true) {
+    if (val == null) { val = {}; }
+    const ctx = {
+      parent,
+      val,
+      pointerSize: 0
+    };
+
+    if (this.preEncode != null) {
+      this.preEncode.call(val);
+    }
+
+    let size = 0;
+    for (let key in this.fields) {
+      const type = this.fields[key];
+      if (type.size != null) {
+        size += type.size(val[key], ctx);
+      }
+    }
+
+    if (includePointers) {
+      size += ctx.pointerSize;
+    }
+
+    return size;
+  }
+
+  encode(stream, val, parent) {
+    let type;
+    if (this.preEncode != null) {
+      this.preEncode.call(val, stream);
+    }
+
+    const ctx = {
+      pointers: [],
+      startOffset: stream.pos,
+      parent,
+      val,
+      pointerSize: 0
+    };
+
+    ctx.pointerOffset = stream.pos + this.size(val, ctx, false);
+
+    for (let key in this.fields) {
+      type = this.fields[key];
+      if (type.encode != null) {
+        type.encode(stream, val[key], ctx);
+      }
+    }
+
+    let i = 0;
+    while (i < ctx.pointers.length) {
+      const ptr = ctx.pointers[i++];
+      ptr.type.encode(stream, ptr.val, ptr.parent);
+    }
+  }
+}

skills/flight-finder/node_modules/restructure/src/VersionedStruct.js

@@ -0,0 +1,139 @@
+import {Struct} from './Struct.js';
+
+const getPath = (object, pathArray) => {
+  return pathArray.reduce((prevObj, key) => prevObj && prevObj[key], object);
+};
+
+export class VersionedStruct extends Struct {
+  constructor(type, versions = {}) {
+    super();
+    this.type = type;
+    this.versions = versions;
+    if (typeof type === 'string') {
+      this.versionPath = type.split('.');
+    }
+  }
+
+  decode(stream, parent, length = 0) {
+    const res = this._setup(stream, parent, length);
+
+    if (typeof this.type === 'string') {
+      res.version = getPath(parent, this.versionPath);
+    } else {
+      res.version = this.type.decode(stream);
+    }
+
+    if (this.versions.header) {
+      this._parseFields(stream, res, this.versions.header);
+    }
+
+    const fields = this.versions[res.version];
+    if ((fields == null)) {
+      throw new Error(`Unknown version ${res.version}`);
+    }
+
+    if (fields instanceof VersionedStruct) {
+      return fields.decode(stream, parent);
+    }
+
+    this._parseFields(stream, res, fields);
+
+    if (this.process != null) {
+      this.process.call(res, stream);
+    }
+    return res;
+  }
+
+  size(val, parent, includePointers = true) {
+    let key, type;
+    if (!val) {
+      throw new Error('Not a fixed size');
+    }
+
+    if (this.preEncode != null) {
+      this.preEncode.call(val);
+    }
+
+    const ctx = {
+      parent,
+      val,
+      pointerSize: 0
+    };
+
+    let size = 0;
+    if (typeof this.type !== 'string') {
+      size += this.type.size(val.version, ctx);
+    }
+
+    if (this.versions.header) {
+      for (key in this.versions.header) {
+        type = this.versions.header[key];
+        if (type.size != null) {
+          size += type.size(val[key], ctx);
+        }
+      }
+    }
+
+    const fields = this.versions[val.version];
+    if ((fields == null)) {
+      throw new Error(`Unknown version ${val.version}`);
+    }
+
+    for (key in fields) {
+      type = fields[key];
+      if (type.size != null) {
+        size += type.size(val[key], ctx);
+      }
+    }
+
+    if (includePointers) {
+      size += ctx.pointerSize;
+    }
+
+    return size;
+  }
+
+  encode(stream, val, parent) {
+    let key, type;
+    if (this.preEncode != null) {
+      this.preEncode.call(val, stream);
+    }
+
+    const ctx = {
+      pointers: [],
+      startOffset: stream.pos,
+      parent,
+      val,
+      pointerSize: 0
+    };
+
+    ctx.pointerOffset = stream.pos + this.size(val, ctx, false);
+
+    if (typeof this.type !== 'string') {
+      this.type.encode(stream, val.version);
+    }
+
+    if (this.versions.header) {
+      for (key in this.versions.header) {
+        type = this.versions.header[key];
+        if (type.encode != null) {
+          type.encode(stream, val[key], ctx);
+        }
+      }
+    }
+
+    const fields = this.versions[val.version];
+    for (key in fields) {
+      type = fields[key];
+      if (type.encode != null) {
+        type.encode(stream, val[key], ctx);
+      }
+    }
+
+    let i = 0;
+    while (i < ctx.pointers.length) {
+      const ptr = ctx.pointers[i++];
+      ptr.type.encode(stream, ptr.val, ptr.parent);
+    }
+  }
+}

skills/flight-finder/node_modules/restructure/src/utils.js

@@ -0,0 +1,35 @@
+import {Number as NumberT} from './Number.js';
+
+export function resolveLength(length, stream, parent) {
+  let res;
+  if (typeof length === 'number') {
+    res = length;
+
+  } else if (typeof length === 'function') {
+    res = length.call(parent, parent);
+
+  } else if (parent && (typeof length === 'string')) {
+    res = parent[length];
+
+  } else if (stream && length instanceof NumberT) {
+    res = length.decode(stream);
+  }
+
+  if (isNaN(res)) {
+    throw new Error('Not a fixed size');
+  }
+
+  return res;
+};
+
+export class PropertyDescriptor {
+  constructor(opts = {}) {
+    this.enumerable = true;
+    this.configurable = true;
+
+    for (let key in opts) {
+      const val = opts[key];
+      this[key] = val;
+    }
+  }
+}