@foxglove/ulog
Version:
PX4 ULog file reader
81 lines • 2.76 kB
JavaScript
;
var __createBinding = (this && this.__createBinding) || (Object.create ? (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
var desc = Object.getOwnPropertyDescriptor(m, k);
if (!desc || ("get" in desc ? !m.__esModule : desc.writable || desc.configurable)) {
desc = { enumerable: true, get: function() { return m[k]; } };
}
Object.defineProperty(o, k2, desc);
}) : (function(o, m, k, k2) {
if (k2 === undefined) k2 = k;
o[k2] = m[k];
}));
var __setModuleDefault = (this && this.__setModuleDefault) || (Object.create ? (function(o, v) {
Object.defineProperty(o, "default", { enumerable: true, value: v });
}) : function(o, v) {
o["default"] = v;
});
var __importStar = (this && this.__importStar) || (function () {
var ownKeys = function(o) {
ownKeys = Object.getOwnPropertyNames || function (o) {
var ar = [];
for (var k in o) if (Object.prototype.hasOwnProperty.call(o, k)) ar[ar.length] = k;
return ar;
};
return ownKeys(o);
};
return function (mod) {
if (mod && mod.__esModule) return mod;
var result = {};
if (mod != null) for (var k = ownKeys(mod), i = 0; i < k.length; i++) if (k[i] !== "default") __createBinding(result, mod, k[i]);
__setModuleDefault(result, mod);
return result;
};
})();
Object.defineProperty(exports, "__esModule", { value: true });
exports.FileReader = void 0;
const fs = __importStar(require("fs/promises"));
/**
* A FileReader implemented using the node.js filesystem API.
*/
class FileReader {
#filename;
#file;
#size = 0;
constructor(filename) {
this.#filename = filename;
}
async open() {
await this.#openHandle();
return this.#size;
}
async #openHandle() {
if (this.#file) {
return this.#file;
}
this.#file = await fs.open(this.#filename, "r");
const size = (await this.#file.stat({ bigint: true })).size;
if (size > Number.MAX_SAFE_INTEGER) {
throw new Error(`File size ${size} exceeds the maximum size`);
}
this.#size = Number(size);
return this.#file;
}
async close() {
await this.#file?.close();
}
/**
* Read up to `length` bytes starting from `offset` bytes.
*/
async read(offset, length) {
const file = await this.#openHandle();
const data = new Uint8Array(length);
const res = await file.read(data, 0, length, offset);
return data.byteLength === res.bytesRead ? data : data.slice(0, res.bytesRead);
}
size() {
return this.#size;
}
}
exports.FileReader = FileReader;
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