feat(DataView, ConstDataView)

src/ConstArray.js

@@ -1,4 +1,4 @@
-import { limits, parse, serialize, sizeofHead, Type } from "."
+import { parse, serialize, sizeofHead, Type } from "."
 
 export function ConstArray(size) {
   const obj = { _size: size }
@@ -8,16 +8,11 @@ export function ConstArray(size) {
 }
 ConstArray.prototype.serialize = function(dv, src, ...inner_types) {
   const item_size = sizeofHead(src[0])
-  let size = this._size
+  const size = this._size
 
   if (dv.byteLength < size * item_size) {
     throw new Error('too small buffer')
   }
-  if (size > limits.u32.MAX_VALUE) {
-    throw new Error('array is too long')
-  }
-
-  dv.setUint32(0, size)
 
   for (let i = 0; i < size; i++) {
     const item_frame = new DataView(dv.buffer, dv.byteOffset + item_size * i)

src/ConstDataView.js

@@ -0,0 +1,31 @@
+import { memcpy, Type } from "."
+
+export function ConstDataView(size) {
+  const obj = { _size: size }
+  Object.setPrototypeOf(obj, ConstDataView.prototype)
+  obj.new(ConstDataView, arguments)
+  return obj
+}
+ConstDataView.prototype.serialize = function(dv, src) {
+  if (dv.byteLength < this._size) {
+    throw new Error('too small buffer')
+  }
+  memcpy(dv, src)
+  return
+}
+ConstDataView.prototype.parse = function(dv) {
+  const res_buffer = new ArrayBuffer(this._size)
+  const res_dv = new DataView(res_buffer)
+
+  memcpy(res_dv, dv)
+
+  return res_dv
+}
+ConstDataView.prototype.isHeadless = function() {
+  return false
+}
+ConstDataView.prototype.sizeof = function() {
+  return this._size
+}
+Object.setPrototypeOf(ConstDataView.prototype, Type.prototype)
+Object.freeze(ConstDataView.prototype)

src/index.js

@@ -3,9 +3,10 @@ import { memcpy } from "./mem"
 import { Type } from "./Type"
 import { ConstString } from './ConstString'
 import { ConstArray } from "./ConstArray"
+import { ConstDataView } from './ConstDataView'
 import { Struct } from './Struct'
 
-export { limits, memcpy, Type, ConstString, ConstArray, Struct }
+export { limits, memcpy, Type, ConstString, ConstArray, ConstDataView, Struct }
 
 export function serialize(dv, src, ...types) {
   const [type, ...inner_types] = types
@@ -54,6 +55,19 @@ export function serialize(dv, src, ...types) {
     }
     return
   }
+  if (type == DataView && src instanceof DataView) {
+    if (dv.byteLength < 4 + src.byteLength) {
+      throw new Error('too small buffer')
+    }
+    if (src.byteLength > limits.u32.MAX_VALUE) {
+      throw new Error('data view is too long')
+    }
+
+    dv.setUint32(0, src.byteLength)
+
+    const frame = new DataView(dv.buffer, dv.byteOffset + 4)
+    memcpy(frame, src)
+  }
   if (type instanceof Type) {
     type.serialize(dv, src, ...inner_types)
     return
@@ -84,6 +98,16 @@ export function parse(dv, ...types) {
 
     return array
   }
+  if (type == DataView) {
+    const size = dv.getUint32(0)
+    const res_buffer = new ArrayBuffer(size)
+    const res_dv = new DataView(res_buffer)
+
+    const frame = new DataView(dv.buffer, dv.byteOffset + 4)
+    memcpy(res_dv, frame)
+
+    return res_dv
+  }
   if (type instanceof Type) {
     return type.parse(dv, ...inner_types)
   }
@@ -96,8 +120,10 @@ export function isHeadless(...args) {
   }
   return arg == Array ||
     arg == String ||
+    arg == DataView ||
     Array.isArray(arg) ||
-    typeof arg == 'string'
+    typeof arg == 'string' ||
+    arg instanceof DataView
 }
 
 export function sizeofHead(...args) {
@@ -121,6 +147,9 @@ export function sizeof(...args) {
   if (Array.isArray(arg)) {
     return 4 + sizeofHead(arg[0]) * arg.length
   }
+  if (arg instanceof DataView) {
+    return 4 + arg.byteLength
+  }
   if (arg instanceof Type) {
     return arg.sizeof(...inner_args)
   }

test/ConstArray.test.js

@@ -1,6 +1,6 @@
 import { describe, expect, test } from "vitest";
 import { ConstArray, parse, serialize, sizeof, sizeofHead } from "../src";
-import { filledDataView, sizedDataView } from ".";
+import { expectDataViewEqual, filledDataView, sizedDataView } from ".";
 
 describe(ConstArray.name, () => {
   test('serialize, Number', () => {
@@ -15,7 +15,7 @@ describe(ConstArray.name, () => {
     expect(16).toEqual(dv.byteLength)
 
     serialize(dv, [1, 2], ConstArray(2), Number)
-    expect(dv).toEqual(expected)
+    expectDataViewEqual(dv, expected)
   })
 
   test('parse, Number', () => {
@@ -25,7 +25,7 @@ describe(ConstArray.name, () => {
       0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     ])
     const actual = parse(dv, ConstArray(2), Number)
-    expect(actual).toEqual(expected)
+    expectDataViewEqual(actual, expected)
   })
 
   test('sizeof', () => {

test/ConstDataView.test.js

@@ -0,0 +1,31 @@
+import { describe, expect, test } from "vitest";
+import { ConstDataView, parse, serialize, sizeofHead } from "../src";
+import { expectDataViewEqual, filledDataView } from ".";
+
+describe(ConstDataView.name, () => {
+  test('serialize', () => {
+    const expected = filledDataView([0x00, 0x00, 0x01, 0x02, 0x00, 0x00])
+    const dv = filledDataView([0x01, 0x02])
+
+    const buffer = new ArrayBuffer(6)
+    let actual = new DataView(buffer, 2, 1)
+    expect(() => serialize(actual, dv, ConstDataView(2))).toThrow()
+
+    actual = new DataView(buffer, 2, 2)
+
+    serialize(actual, dv, ConstDataView(2))
+    expectDataViewEqual(new DataView(actual.buffer), expected)
+  })
+
+  test('parse', () => {
+    const expected = filledDataView([0x01, 0x02])
+    const dv = filledDataView([0x00, 0x00, 0x01, 0x02, 0x00, 0x00])
+    const frame = new DataView(dv.buffer, dv.byteOffset + 2, 2)
+    const actual = parse(frame, ConstDataView(2))
+    expectDataViewEqual(actual, expected)
+  })
+
+  test('sizeof', () => {
+    expect(sizeofHead(ConstDataView(2))).toEqual(2)
+  })
+})

test/ConstString.test.js

@@ -1,6 +1,6 @@
 import { describe, expect, test } from "vitest";
 import { ConstString, parse, serialize, sizeofHead } from "../src";
-import { filledDataView, sizedDataView } from ".";
+import { expectDataViewEqual, filledDataView, sizedDataView } from ".";
 
 describe(ConstString.name, () => {
   test('serialize', () => {
@@ -11,14 +11,14 @@ describe(ConstString.name, () => {
     dv = sizedDataView(5)
 
     serialize(dv, 'hello', ConstString(3))
-    expect(dv).toEqual(expected)
+    expectDataViewEqual(dv, expected)
   })
 
   test('parse', () => {
     const expected = 'hel'
     const dv = filledDataView([0x68, 0x65, 0x6C, 0x6C, 0x6F])
     const actual = parse(dv, ConstString(3))
-    expect(actual).toEqual(expected)
+    expectDataViewEqual(actual, expected)
   })
 
   test('sizeof', () => {

test/Struct.test.js

@@ -1,6 +1,6 @@
 import { describe, expect, test } from "vitest";
 import { parse, serialize, sizeof, Struct } from "../src";
-import { filledDataView, sizedDataView } from ".";
+import { expectDataViewEqual, filledDataView, sizedDataView } from ".";
 
 describe(Struct.name, () => {
   
@@ -20,11 +20,11 @@ describe(Struct.name, () => {
     expect(21).toEqual(dv.byteLength)
 
     serialize(dv, user, User)
-    expect(dv).toEqual(user_dv)
+    expectDataViewEqual(dv, user_dv)
   })
 
   test('parse, headless', () => {
-    expect(parse(user_dv, User)).toEqual(user)
+    expectDataViewEqual(parse(user_dv, User), user)
   })
 
   const Vector2 = Struct({ x: Number, y: Number })
@@ -39,11 +39,11 @@ describe(Struct.name, () => {
     expect(16).toEqual(dv.byteLength)
 
     serialize(dv, vector2, Vector2)
-    expect(dv).toEqual(vector2_dv)
+    expectDataViewEqual(dv, vector2_dv)
   })
 
   test('parse, non-headless', () => {
-    expect(parse(vector2_dv, Vector2)).toEqual(vector2)
+    expectDataViewEqual(parse(vector2_dv, Vector2), vector2)
   })
 
   const Nested = Struct({ user: User, vector2: [Vector2] })
@@ -61,10 +61,10 @@ describe(Struct.name, () => {
   test('serialize, nested', () => {
     const dv = sizedDataView(sizeof(nested, Nested))
     serialize(dv, nested, Nested)
-    expect(dv).toEqual(nested_dv)
+    expectDataViewEqual(dv, nested_dv)
   })
 
   test('parse, nested', () => {
-    expect(parse(nested_dv, Nested)).toEqual(nested)
+    expectDataViewEqual(parse(nested_dv, Nested), nested)
   })
 })

test/index.js

@@ -1,3 +1,5 @@
+import { expect } from "vitest"
+
 export function filledDataView(bytes) {
   const ab = new ArrayBuffer(bytes.length)
   const dv = new DataView(ab)
@@ -13,3 +15,22 @@ export function sizedDataView(length) {
   const ab = new ArrayBuffer(length)
   return new DataView(ab)
 }
+
+export function expectDataViewEqual(actual, expected) {
+  const actualBytes = new Uint8Array(actual.buffer, actual.byteOffset, actual.byteLength)
+  const expectedBytes = new Uint8Array(expected.buffer, expected.byteOffset, expected.byteLength)
+
+  if (actualBytes.length !== expectedBytes.length) {
+    throw new Error(`DataView length mismatch: ${actualBytes.length} !== ${expectedBytes.length}`)
+  }
+
+  for (let i = 0; i < actualBytes.length; i++) {
+    if (actualBytes[i] !== expectedBytes[i]) {
+      throw new Error(
+        `Byte mismatch at offset ${i}: 0x${actualBytes[i].toString(16)} !== 0x${expectedBytes[i].toString(16)}\n` +
+        `actual:   [${Array.from(actualBytes).map(byte => '0x' + byte.toString(16)).join(', ')}]\n` +
+        `expected: [${Array.from(expectedBytes).map(byte => '0x' + byte.toString(16)).join(', ')}]`
+      )
+    }
+  }
+}

test/index.test.js

@@ -1,5 +1,5 @@
 import { describe, test, expect } from 'vitest'
-import { filledDataView, sizedDataView } from '.'
+import { expectDataViewEqual, filledDataView, sizedDataView } from '.'
 import { parse, serialize, sizeof, sizeofHead } from '../src'
 
 describe('serialize', () => {
@@ -12,7 +12,7 @@ describe('serialize', () => {
     expect(8).toEqual(dv.byteLength)
     
     serialize(dv, 1532.625, Number)
-    expect(dv).toEqual(expected)
+    expectDataViewEqual(dv, expected)
   })
   test('String', () => {
     const expected = filledDataView([
@@ -26,7 +26,7 @@ describe('serialize', () => {
     expect(9).toEqual(dv.byteLength)
 
     serialize(dv, 'hello', String)
-    expect(dv).toEqual(expected)
+    expectDataViewEqual(dv, expected)
   })
   test('Array, Number', () => {
     const expected = filledDataView([
@@ -41,7 +41,22 @@ describe('serialize', () => {
     expect(20).toEqual(dv.byteLength)
 
     serialize(dv, [1, 2], Array, Number)
-    expect(dv).toEqual(expected)
+    expectDataViewEqual(dv, expected)
+  })
+  test('DataView', () => {
+    const expected = filledDataView([
+      0x00, 0x00, 0x00, 0x04,
+      0x00, 0x01, 0x02, 0x03,
+    ])
+    const dv = filledDataView([
+      0x00, 0x01, 0x02, 0x03,
+    ])
+    let actual = sizedDataView(7)
+    expect(() => serialize(actual, dv, DataView)).toThrow()
+
+    actual = sizedDataView(8)
+    serialize(actual, dv, DataView)
+    expectDataViewEqual(actual, expected)
   })
 })
 
@@ -50,7 +65,7 @@ describe('parse', () => {
     const expected = 1532.625
     const dv = filledDataView([0x40, 0x97, 0xF2, 0x80, 0x00, 0x00, 0x00, 0x00])
     const actual = parse(dv, Number)
-    expect(actual).toEqual(expected)
+    expectDataViewEqual(actual, expected)
   })
   test('String', () => {
     const expected = 'hello'
@@ -59,7 +74,7 @@ describe('parse', () => {
       0x68, 0x65, 0x6C, 0x6C, 0x6F
     ])
     const actual = parse(dv, String)
-    expect(actual).toEqual(expected)
+    expectDataViewEqual(actual, expected)
   })
   test('Array, Number', () => {
     const expected = [1, 2]
@@ -69,7 +84,18 @@ describe('parse', () => {
       0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
     ])
     const actual = parse(dv, Array, Number)
-    expect(actual).toEqual(expected)
+    expectDataViewEqual(actual, expected)
+  })
+  test('DataView', () => {
+    const expected = filledDataView([
+      0x00, 0x01, 0x02, 0x03,
+    ])
+    const dv = filledDataView([
+      0x00, 0x00, 0x00, 0x04,
+      0x00, 0x01, 0x02, 0x03,
+    ])
+    const actual = parse(dv, DataView)
+    expectDataViewEqual(actual, expected)
   })
 })
 

types/ConstDataView.d.ts

@@ -0,0 +1,8 @@
+import { Type } from ".";
+
+/**
+  * constructs type of data view with constant byte size
+  * @param {number} byte_size max byte size
+  * @returns {Type}
+  */
+export function ConstDataView(byte_size: number): Type;

types/index.d.ts

@@ -3,19 +3,20 @@ import { limits } from "./limits";
 import { Type } from "./Type"
 import { ConstString } from "./ConstString"
 import { ConstArray } from "./ConstArray";
+import { ConstDataView } from "./ConstDataView"; 
 import { Struct } from "./Struct";
 
-export { memcpy, limits, Type, ConstString, ConstArray, Struct }
+export { memcpy, limits, Type, ConstString, ConstArray, ConstDataView, Struct }
 
-export type SerializableType = NumberConstructor | StringConstructor | ArrayConstructor | Type
-export type Serializable = number | string | array
+export type SerializableType = NumberConstructor | StringConstructor | ArrayConstructor | DataViewConstructor | Type
+export type Serializable = number | string | array | DataView
 
 /**
   * @param {DataView} dv destination memory
   * @param {Serializable} src source object
   * @param {SerializableType[]} ...types primary and inner types. eg: Array, Number
   * @throws {Error} if too small buffer
-  * @throws {Error} if array|string size is higher than limits.u32.MAX_VALUE
+  * @throws {Error} if array|string|DataView size is higher than limits.u32.MAX_VALUE
   */
 export function serialize(dv: DataView, src: Serializable, ...types: SerializableType[]): void;
 
@@ -66,6 +67,6 @@ export function sizeof(obj: Serializable, ...types: SerializableType[]): number;
 /**
   * @param {SerializableType[]} ...types primary and inner types. eg: Array, Number
   * @returns {number}
-  * @throws {Error} if passed Array or String type (unknown sizeof)
+  * @throws {Error} if passed Array, String, DataView type (unknown sizeof)
   */
 export function sizeof(...types: SerializableType[]): number;