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// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements. See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership. The ASF licenses this file
// to you under the Apache License, Version 2.0 (the
// "License"); you may not use this file except in compliance
// with the License. You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied. See the License for the
// specific language governing permissions and limitations
// under the License.
import { FileHandle } from './interfaces.js';
import { ByteStream, AsyncByteStream } from './stream.js';
import { ArrayBufferViewInput, toUint8Array } from '../util/buffer.js';
/** @ignore */
export class RandomAccessFile extends ByteStream {
public size: number;
public position = 0;
protected buffer: Uint8Array | null;
constructor(buffer: ArrayBufferViewInput, byteLength?: number) {
super();
this.buffer = toUint8Array(buffer);
this.size = typeof byteLength === 'undefined' ? this.buffer!.byteLength : byteLength;
}
public readInt32(position: number) {
const { buffer, byteOffset } = this.readAt(position, 4);
return new DataView(buffer, byteOffset).getInt32(0, true);
}
public seek(position: number) {
this.position = Math.min(position, this.size);
return position < this.size;
}
public read(nBytes?: number | null) {
const { buffer, size, position } = this;
if (buffer && position < size) {
if (typeof nBytes !== 'number') { nBytes = Number.POSITIVE_INFINITY; }
this.position = Math.min(size,
position + Math.min(size - position, nBytes));
return buffer.subarray(position, this.position);
}
return null;
}
public readAt(position: number, nBytes: number) {
const buf = this.buffer;
const end = Math.min(this.size, position + nBytes);
return buf ? buf.subarray(position, end) : new Uint8Array(nBytes);
}
public close() { this.buffer && (this.buffer = null); }
public throw(value?: any) { this.close(); return { done: true, value }; }
public return(value?: any) { this.close(); return { done: true, value }; }
}
/** @ignore */
export class AsyncRandomAccessFile extends AsyncByteStream {
declare public size: number;
public position = 0;
public _pending?: Promise<void>;
protected _handle: FileHandle | null;
constructor(file: FileHandle, byteLength?: number) {
super();
this._handle = file;
if (typeof byteLength === 'number') {
this.size = byteLength;
} else {
this._pending = (async () => {
this.size = (await file.stat()).size;
delete this._pending;
})();
}
}
public async readInt32(position: number) {
const { buffer, byteOffset } = await this.readAt(position, 4);
return new DataView(buffer, byteOffset).getInt32(0, true);
}
public async seek(position: number) {
this._pending && await this._pending;
this.position = Math.min(position, this.size);
return position < this.size;
}
public async read(nBytes?: number | null) {
this._pending && await this._pending;
const { _handle: file, size, position } = this;
if (file && position < size) {
if (typeof nBytes !== 'number') { nBytes = Number.POSITIVE_INFINITY; }
let pos = position, offset = 0, bytesRead = 0;
const end = Math.min(size, pos + Math.min(size - pos, nBytes));
const buffer = new Uint8Array(Math.max(0, (this.position = end) - pos));
while ((pos += bytesRead) < end && (offset += bytesRead) < buffer.byteLength) {
({ bytesRead } = await file.read(buffer, offset, buffer.byteLength - offset, pos));
}
return buffer;
}
return null;
}
public async readAt(position: number, nBytes: number) {
this._pending && await this._pending;
const { _handle: file, size } = this;
if (file && (position + nBytes) < size) {
const end = Math.min(size, position + nBytes);
const buffer = new Uint8Array(end - position);
return (await file.read(buffer, 0, nBytes, position)).buffer;
}
return new Uint8Array(nBytes);
}
public async close() { const f = this._handle; this._handle = null; f && await f.close(); }
public async throw(value?: any) { await this.close(); return { done: true, value }; }
public async return(value?: any) { await this.close(); return { done: true, value }; }
}
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