@loaders.gl/wkt
Version:
Loader and Writer for the WKT (Well Known Text) Format
70 lines (69 loc) • 2.12 kB
JavaScript
// loaders.gl
// SPDX-License-Identifier: MIT
// Copyright (c) vis.gl contributors
/** A DataView that tracks byte offset when reading. */
export class BinaryReader {
arrayBuffer;
dataView;
byteOffset;
littleEndian;
constructor(arrayBuffer, isBigEndian = false) {
this.arrayBuffer = arrayBuffer;
this.dataView = new DataView(arrayBuffer);
this.byteOffset = 0;
this.littleEndian = !isBigEndian;
}
readUInt8() {
const value = this.dataView.getUint8(this.byteOffset);
this.byteOffset += 1;
return value;
}
readUInt16() {
const value = this.dataView.getUint16(this.byteOffset, this.littleEndian);
this.byteOffset += 2;
return value;
}
readUInt32() {
const value = this.dataView.getUint32(this.byteOffset, this.littleEndian);
this.byteOffset += 4;
return value;
}
readInt8() {
const value = this.dataView.getInt8(this.byteOffset);
this.byteOffset += 1;
return value;
}
readInt16() {
const value = this.dataView.getInt16(this.byteOffset, this.littleEndian);
this.byteOffset += 2;
return value;
}
readInt32() {
const value = this.dataView.getInt32(this.byteOffset, this.littleEndian);
this.byteOffset += 4;
return value;
}
readFloat() {
const value = this.dataView.getFloat32(this.byteOffset, this.littleEndian);
this.byteOffset += 4;
return value;
}
readDouble() {
const value = this.dataView.getFloat64(this.byteOffset, this.littleEndian);
this.byteOffset += 8;
return value;
}
readVarInt() {
let result = 0;
let bytesRead = 0;
let nextByte;
do {
// TODO - this needs to be accessed via data view?
nextByte = this.dataView.getUint8(this.byteOffset + bytesRead);
result += (nextByte & 0x7f) << (7 * bytesRead);
bytesRead++;
} while (nextByte >= 0x80);
this.byteOffset += bytesRead;
return result;
}
}