multi-buffer-data-view
Version:
A wrapper around the native DataView which can handle multiple ArrayBuffers.
165 lines (164 loc) • 7.91 kB
JavaScript
"use strict";
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.MultiBufferDataView = void 0;
class MultiBufferDataView {
constructor(buffers, byteOffset = 0, byteLength) {
if (byteOffset < 0 || byteLength !== undefined && byteLength < 0) {
throw new RangeError();
}
const availableBytes = buffers.reduce((length, buffer) => length + buffer.byteLength, 0);
if (byteOffset > availableBytes || byteLength !== undefined && byteOffset + byteLength > availableBytes) {
throw new RangeError();
}
const dataViews = [];
const effectiveByteLength = byteLength === undefined ? availableBytes - byteOffset : byteLength;
const truncatedBuffers = [];
let consumedByteLength = 0;
let truncatedByteOffset = byteOffset;
for (const buffer of buffers) {
if (truncatedBuffers.length === 0) {
if (buffer.byteLength > truncatedByteOffset) {
consumedByteLength = buffer.byteLength - truncatedByteOffset;
const byteLengthOfDataView = consumedByteLength > effectiveByteLength ? effectiveByteLength : consumedByteLength;
dataViews.push(new DataView(buffer, truncatedByteOffset, byteLengthOfDataView));
truncatedBuffers.push(buffer);
} else {
truncatedByteOffset -= buffer.byteLength;
}
} else if (consumedByteLength < effectiveByteLength) {
consumedByteLength += buffer.byteLength;
const byteLengthOfDataView = consumedByteLength > effectiveByteLength ? buffer.byteLength - consumedByteLength + effectiveByteLength : buffer.byteLength;
dataViews.push(new DataView(buffer, 0, byteLengthOfDataView));
truncatedBuffers.push(buffer);
}
}
this._buffers = truncatedBuffers;
this._byteLength = effectiveByteLength;
this._byteOffset = truncatedByteOffset;
this._dataViews = dataViews;
this._internalBuffer = new DataView(new ArrayBuffer(8));
}
get buffers() {
return this._buffers;
}
get byteLength() {
return this._byteLength;
}
get byteOffset() {
return this._byteOffset;
}
getFloat32(byteOffset, littleEndian) {
this._internalBuffer.setUint8(0, this.getUint8(byteOffset + 0));
this._internalBuffer.setUint8(1, this.getUint8(byteOffset + 1));
this._internalBuffer.setUint8(2, this.getUint8(byteOffset + 2));
this._internalBuffer.setUint8(3, this.getUint8(byteOffset + 3));
return this._internalBuffer.getFloat32(0, littleEndian);
}
getFloat64(byteOffset, littleEndian) {
this._internalBuffer.setUint8(0, this.getUint8(byteOffset + 0));
this._internalBuffer.setUint8(1, this.getUint8(byteOffset + 1));
this._internalBuffer.setUint8(2, this.getUint8(byteOffset + 2));
this._internalBuffer.setUint8(3, this.getUint8(byteOffset + 3));
this._internalBuffer.setUint8(4, this.getUint8(byteOffset + 4));
this._internalBuffer.setUint8(5, this.getUint8(byteOffset + 5));
this._internalBuffer.setUint8(6, this.getUint8(byteOffset + 6));
this._internalBuffer.setUint8(7, this.getUint8(byteOffset + 7));
return this._internalBuffer.getFloat64(0, littleEndian);
}
getInt16(byteOffset, littleEndian) {
this._internalBuffer.setUint8(0, this.getUint8(byteOffset + 0));
this._internalBuffer.setUint8(1, this.getUint8(byteOffset + 1));
return this._internalBuffer.getInt16(0, littleEndian);
}
getInt32(byteOffset, littleEndian) {
this._internalBuffer.setUint8(0, this.getUint8(byteOffset + 0));
this._internalBuffer.setUint8(1, this.getUint8(byteOffset + 1));
this._internalBuffer.setUint8(2, this.getUint8(byteOffset + 2));
this._internalBuffer.setUint8(3, this.getUint8(byteOffset + 3));
return this._internalBuffer.getInt32(0, littleEndian);
}
getInt8(byteOffset) {
const [dataView, byteOffsetOfDataView] = this._findDataViewWithOffset(byteOffset);
return dataView.getInt8(byteOffset - byteOffsetOfDataView);
}
getUint16(byteOffset, littleEndian) {
this._internalBuffer.setUint8(0, this.getUint8(byteOffset + 0));
this._internalBuffer.setUint8(1, this.getUint8(byteOffset + 1));
return this._internalBuffer.getUint16(0, littleEndian);
}
getUint32(byteOffset, littleEndian) {
this._internalBuffer.setUint8(0, this.getUint8(byteOffset + 0));
this._internalBuffer.setUint8(1, this.getUint8(byteOffset + 1));
this._internalBuffer.setUint8(2, this.getUint8(byteOffset + 2));
this._internalBuffer.setUint8(3, this.getUint8(byteOffset + 3));
return this._internalBuffer.getUint32(0, littleEndian);
}
getUint8(byteOffset) {
const [dataView, byteOffsetOfDataView] = this._findDataViewWithOffset(byteOffset);
return dataView.getUint8(byteOffset - byteOffsetOfDataView);
}
setFloat32(byteOffset, value, littleEndian) {
this._internalBuffer.setFloat32(0, value, littleEndian);
this.setUint8(byteOffset, this._internalBuffer.getUint8(0));
this.setUint8(byteOffset + 1, this._internalBuffer.getUint8(1));
this.setUint8(byteOffset + 2, this._internalBuffer.getUint8(2));
this.setUint8(byteOffset + 3, this._internalBuffer.getUint8(3));
}
setFloat64(byteOffset, value, littleEndian) {
this._internalBuffer.setFloat64(0, value, littleEndian);
this.setUint8(byteOffset, this._internalBuffer.getUint8(0));
this.setUint8(byteOffset + 1, this._internalBuffer.getUint8(1));
this.setUint8(byteOffset + 2, this._internalBuffer.getUint8(2));
this.setUint8(byteOffset + 3, this._internalBuffer.getUint8(3));
this.setUint8(byteOffset + 4, this._internalBuffer.getUint8(4));
this.setUint8(byteOffset + 5, this._internalBuffer.getUint8(5));
this.setUint8(byteOffset + 6, this._internalBuffer.getUint8(6));
this.setUint8(byteOffset + 7, this._internalBuffer.getUint8(7));
}
setInt16(byteOffset, value, littleEndian) {
this._internalBuffer.setInt16(0, value, littleEndian);
this.setUint8(byteOffset, this._internalBuffer.getUint8(0));
this.setUint8(byteOffset + 1, this._internalBuffer.getUint8(1));
}
setInt32(byteOffset, value, littleEndian) {
this._internalBuffer.setInt32(0, value, littleEndian);
this.setUint8(byteOffset, this._internalBuffer.getUint8(0));
this.setUint8(byteOffset + 1, this._internalBuffer.getUint8(1));
this.setUint8(byteOffset + 2, this._internalBuffer.getUint8(2));
this.setUint8(byteOffset + 3, this._internalBuffer.getUint8(3));
}
setInt8(byteOffset, value) {
const [dataView, byteOffsetOfDataView] = this._findDataViewWithOffset(byteOffset);
dataView.setInt8(byteOffset - byteOffsetOfDataView, value);
}
setUint16(byteOffset, value, littleEndian) {
this._internalBuffer.setUint16(0, value, littleEndian);
this.setUint8(byteOffset, this._internalBuffer.getUint8(0));
this.setUint8(byteOffset + 1, this._internalBuffer.getUint8(1));
}
setUint32(byteOffset, value, littleEndian) {
this._internalBuffer.setUint32(0, value, littleEndian);
this.setUint8(byteOffset, this._internalBuffer.getUint8(0));
this.setUint8(byteOffset + 1, this._internalBuffer.getUint8(1));
this.setUint8(byteOffset + 2, this._internalBuffer.getUint8(2));
this.setUint8(byteOffset + 3, this._internalBuffer.getUint8(3));
}
setUint8(byteOffset, value) {
const [dataView, byteOffsetOfDataView] = this._findDataViewWithOffset(byteOffset);
dataView.setUint8(byteOffset - byteOffsetOfDataView, value);
}
_findDataViewWithOffset(byteOffset) {
let byteOffsetOfDataView = 0;
for (const dataView of this._dataViews) {
const byteOffsetOfNextDataView = byteOffsetOfDataView + dataView.byteLength;
if (byteOffset >= byteOffsetOfDataView && byteOffset < byteOffsetOfNextDataView) {
return [dataView, byteOffsetOfDataView];
}
byteOffsetOfDataView = byteOffsetOfNextDataView;
}
throw new RangeError();
}
}
exports.MultiBufferDataView = MultiBufferDataView;