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First pass at DataView implementation.
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@alex-kulcsar
alex-kulcsar committed Oct 20, 2024
1 parent eefa305 commit dc3d4b6
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Showing 2 changed files with 129 additions and 32 deletions.
133 changes: 106 additions & 27 deletions dataView.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -42,17 +42,17 @@ class DataView {

public constructor(buffer: ArrayBuffer,
byteOffset: number = 0,
byteLength: number = 0
byteLength: number = null
) {
byteOffset = byteOffset >>> 0
if (byteOffset > buffer.byteLength) {
throw "byteOffset is out of range."
}

if (byteLength === undefined) {
if (byteLength === undefined || byteLength == null) {
byteLength = buffer.byteLength - byteOffset
} else {
byteLength = byteLength >> 0
byteLength = byteLength >>> 0
}

if ((byteOffset + byteLength) > buffer.byteLength) {
Expand All @@ -76,13 +76,21 @@ class DataView {
return this._byteOffset
}

public static get IS_BIG_ENDIAN(): boolean {
let u16: Uint16Array = new Uint16Array()
let u8: Uint8Array = new Uint8Array()
u16.fromArray([0x1234,])
u8.fromArrayBuffer(u16.buffer)
return (u8.get(0) === 0x12)
}

/**
* Gets the Float32 value at the specified byte offset from the start of the view. There is
* no alignment constraint; multi-byte values may be fetched from any offset.
* @param byteOffset The place in the buffer at which the value should be retrieved.
* @param littleEndian If false or undefined, a big-endian value should be read.
*/
public getFloat32(byteOffset: number, littleEndian?: boolean): number {
public getFloat32(byteOffset: number, littleEndian: boolean = false): number {
throw "Not yet implemented."
}

Expand All @@ -92,7 +100,7 @@ class DataView {
* @param byteOffset The place in the buffer at which the value should be retrieved.
* @param littleEndian If false or undefined, a big-endian value should be read.
*/
public getFloat64(byteOffset: number, littleEndian?: boolean): number {
public getFloat64(byteOffset: number, littleEndian: boolean = false): number {
throw "Not yet implemented."
}

Expand All @@ -102,7 +110,8 @@ class DataView {
* @param byteOffset The place in the buffer at which the value should be retrieved.
*/
public getInt8(byteOffset: number): number {
throw "Not yet implemented."
let r: Int8Array = new Int8Array()
return this.getter(r, byteOffset)
}

/**
Expand All @@ -111,8 +120,9 @@ class DataView {
* @param byteOffset The place in the buffer at which the value should be retrieved.
* @param littleEndian If false or undefined, a big-endian value should be read.
*/
public getInt16(byteOffset: number, littleEndian?: boolean): number {
throw "Not yet implemented."
public getInt16(byteOffset: number, littleEndian: boolean = false): number {
let r: Int16Array = new Int16Array()
return this.getter(r, byteOffset, littleEndian)
}

/**
Expand All @@ -121,8 +131,9 @@ class DataView {
* @param byteOffset The place in the buffer at which the value should be retrieved.
* @param littleEndian If false or undefined, a big-endian value should be read.
*/
public getInt32(byteOffset: number, littleEndian?: boolean): number {
throw "Not yet implemented."
public getInt32(byteOffset: number, littleEndian: boolean = false): number {
let r: Int32Array = new Int32Array()
return this.getter(r, byteOffset, littleEndian)
}

/**
Expand All @@ -131,7 +142,8 @@ class DataView {
* @param byteOffset The place in the buffer at which the value should be retrieved.
*/
public getUint8(byteOffset: number): number {
throw "Not yet implemented."
let r: Uint8Array = new Uint8Array()
return this.getter(r, byteOffset)
}

/**
Expand All @@ -140,8 +152,9 @@ class DataView {
* @param byteOffset The place in the buffer at which the value should be retrieved.
* @param littleEndian If false or undefined, a big-endian value should be read.
*/
public getUint16(byteOffset: number, littleEndian?: boolean): number {
throw "Not yet implemented."
public getUint16(byteOffset: number, littleEndian: boolean = false): number {
let r: Uint16Array = new Uint16Array()
return this.getter(r, byteOffset, littleEndian)
}

/**
Expand All @@ -150,8 +163,9 @@ class DataView {
* @param byteOffset The place in the buffer at which the value should be retrieved.
* @param littleEndian If false or undefined, a big-endian value should be read.
*/
public getUint32(byteOffset: number, littleEndian?: boolean): number {
throw "Not yet implemented."
public getUint32(byteOffset: number, littleEndian: boolean = false): number {
let r: Uint32Array = new Uint32Array()
return this.getter(r, byteOffset, littleEndian)
}

/**
Expand All @@ -160,7 +174,7 @@ class DataView {
* @param value The value to set.
* @param littleEndian If false or undefined, a big-endian value should be written.
*/
public setFloat32(byteOffset: number, value: number, littleEndian?: boolean): void {
public setFloat32(byteOffset: number, value: number, littleEndian: boolean = false): void {
throw "Not yet implemented."
}

Expand All @@ -170,7 +184,7 @@ class DataView {
* @param value The value to set.
* @param littleEndian If false or undefined, a big-endian value should be written.
*/
public setFloat64(byteOffset: number, value: number, littleEndian?: boolean): void {
public setFloat64(byteOffset: number, value: number, littleEndian: boolean = false): void {
throw "Not yet implemented."
}

Expand All @@ -180,7 +194,8 @@ class DataView {
* @param value The value to set.
*/
public setInt8(byteOffset: number, value: number): void {
throw "Not yet implemented."
let r: Int8Array = new Int8Array()
this.setter(r, byteOffset, value)
}

/**
Expand All @@ -189,8 +204,9 @@ class DataView {
* @param value The value to set.
* @param littleEndian If false or undefined, a big-endian value should be written.
*/
public setInt16(byteOffset: number, value: number, littleEndian?: boolean): void {
throw "Not yet implemented."
public setInt16(byteOffset: number, value: number, littleEndian: boolean = false): void {
let r: Int16Array = new Int16Array()
this.setter(r, byteOffset, value, littleEndian)
}

/**
Expand All @@ -199,8 +215,9 @@ class DataView {
* @param value The value to set.
* @param littleEndian If false or undefined, a big-endian value should be written.
*/
public setInt32(byteOffset: number, value: number, littleEndian?: boolean): void {
throw "Not yet implemented."
public setInt32(byteOffset: number, value: number, littleEndian: boolean = false): void {
let r: Int32Array = new Int32Array()
this.setter(r, byteOffset, value, littleEndian)
}

/**
Expand All @@ -209,7 +226,8 @@ class DataView {
* @param value The value to set.
*/
public setUint8(byteOffset: number, value: number): void {
throw "Not yet implemented."
let r: Uint8Array = new Uint8Array()
this.setter(r, byteOffset, value)
}

/**
Expand All @@ -218,8 +236,9 @@ class DataView {
* @param value The value to set.
* @param littleEndian If false or undefined, a big-endian value should be written.
*/
public setUint16(byteOffset: number, value: number, littleEndian?: boolean): void {
throw "Not yet implemented."
public setUint16(byteOffset: number, value: number, littleEndian: boolean = false): void {
let r: Uint16Array = new Uint16Array()
this.setter(r, byteOffset, value, littleEndian)
}

/**
Expand All @@ -228,7 +247,67 @@ class DataView {
* @param value The value to set.
* @param littleEndian If false or undefined, a big-endian value should be written.
*/
public setUint32(byteOffset: number, value: number, littleEndian?: boolean): void {
throw "Not yet implemented."
public setUint32(byteOffset: number, value: number, littleEndian: boolean = false): void {
let r: Uint32Array = new Uint32Array()
this.setter(r, byteOffset, value, littleEndian)
}

protected getter(
r: TypedArray,
byteOffset: number,
littleEndian: boolean = false
): number {
byteOffset = byteOffset >>> 0
if (byteOffset + r.bytesPerElement > this.byteLength) {
throw "Array index out of range."
}

byteOffset += this.byteOffset

let u8 = new Uint8Array()
u8.fromArrayBuffer(this.buffer, byteOffset, r.bytesPerElement)
let bytes: number[] = []
for (let i: number = 0; i < r.bytesPerElement; i++) {
bytes.push(u8.get(i))
}
if (littleEndian == DataView.IS_BIG_ENDIAN) {
bytes.reverse()
}
let r8: Uint8Array = new Uint8Array()
r8.fromArray(bytes)
r.fromArrayBuffer(r8.buffer)
return r.get(0)
}

protected setter(
r: TypedArray,
byteOffset: number,
value: number,
littleEndian: boolean = false
): void {
byteOffset = byteOffset >>> 0
if (byteOffset + r.bytesPerElement > this.byteLength) {
throw "Array index out of range."
}

// Get bytes.
r.fromArray([value,])
let byteArray: Uint8Array = new Uint8Array()
byteArray.fromArrayBuffer(r.buffer)
let bytes: number[] = []

for (let i: number = 0; i < r.bytesPerElement; i++) {
bytes.push(byteArray.get(i))
}

// Flip if necessary.
if (littleEndian == DataView.IS_BIG_ENDIAN) {
bytes.reverse()
}

// Write them.
let byteView: Uint8Array = new Uint8Array()
byteView.fromArrayBuffer(this.buffer, byteOffset, r.bytesPerElement)
byteView.setFromArray(bytes)
}
}
28 changes: 23 additions & 5 deletions test.ts
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,11 +20,29 @@ function areEquivalent(a: number[], b: TypedArray): boolean {
return true
}

let a: Uint8Array = new Uint8Array()
a.fromArray([0, 1, 2, 3, 4, 5, 6, 7,])
let r: ArrayBuffer = a.buffer
let b: Int8Array = new Int8Array()
b.fromArrayBuffer(r)
game.splash(`Big endian: ${DataView.IS_BIG_ENDIAN}`)

let d: DataView = new DataView(new ArrayBuffer(8))
d.setUint32(0, 0x12345678)
if (d.getUint32(0) != 0x12345678) {
game.splash("DataView constructor test 1 failed.")
allPassed = false
}
d.setUint32(0, 0x12345678, true)
if (d.getUint32(0, true) != 0x12345678) {
game.splash("DataView constructor test 2 failed.")
allPassed = false
}
d.setUint32(0, 0x12345678, true)
if (d.getUint32(0) != 0x78563412) {
game.splash("DataView constructor test 3 failed.")
allPassed = false
}
d.setUint32(0, 0x12345678)
if (d.getUint32(0, true) != 0x78563412) {
game.splash("DataView constructor test 4 failed.")
allPassed = false
}

if (allPassed) {
game.splash("All tests passed!")
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