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659 lines
20 KiB
TypeScript
659 lines
20 KiB
TypeScript
// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
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// This module is browser compatible.
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import { copy } from "@std/bytes/copy";
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import type { Reader } from "./types.ts";
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const DEFAULT_BUF_SIZE = 4096;
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const MIN_BUF_SIZE = 16;
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const MAX_CONSECUTIVE_EMPTY_READS = 100;
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const CR = "\r".charCodeAt(0);
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const LF = "\n".charCodeAt(0);
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/**
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* Thrown when a write operation is attempted on a full buffer.
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*
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* @example Usage
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* ```ts
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* import { BufWriter, BufferFullError, Writer } from "@std/io";
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* import { assert, assertEquals } from "@std/assert";
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*
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* const writer: Writer = {
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* write(p: Uint8Array): Promise<number> {
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* throw new BufferFullError(p);
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* }
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* };
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* const bufWriter = new BufWriter(writer);
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* try {
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* await bufWriter.write(new Uint8Array([1, 2, 3]));
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* } catch (err) {
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* assert(err instanceof BufferFullError);
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* assertEquals(err.partial, new Uint8Array([3]));
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* }
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* ```
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*
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* @deprecated This will be removed in 1.0.0. Use the {@link https://developer.mozilla.org/en-US/docs/Web/API/Streams_API | Web Streams API} instead.
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*/
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export class BufferFullError extends Error {
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/**
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* The partially read bytes
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*
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* @example Usage
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* ```ts
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* import { BufferFullError } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const err = new BufferFullError(new Uint8Array(2));
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* assertEquals(err.partial, new Uint8Array(2));
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* ```
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*/
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partial: Uint8Array;
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/**
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* Construct a new instance.
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*
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* @param partial The bytes partially read
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*/
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constructor(partial: Uint8Array) {
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super("Buffer full");
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this.name = this.constructor.name;
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this.partial = partial;
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}
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}
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/**
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* Thrown when a read from a stream fails to read the
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* requested number of bytes.
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*
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* @example Usage
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* ```ts
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* import { PartialReadError } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const err = new PartialReadError(new Uint8Array(2));
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* assertEquals(err.name, "PartialReadError");
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*
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* ```
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*
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* @deprecated This will be removed in 1.0.0. Use the {@link https://developer.mozilla.org/en-US/docs/Web/API/Streams_API | Web Streams API} instead.
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*/
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export class PartialReadError extends Error {
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/**
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* The partially read bytes
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*
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* @example Usage
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* ```ts
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* import { PartialReadError } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const err = new PartialReadError(new Uint8Array(2));
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* assertEquals(err.partial, new Uint8Array(2));
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* ```
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*/
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partial: Uint8Array;
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/**
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* Construct a {@linkcode PartialReadError}.
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*
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* @param partial The bytes partially read
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*/
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constructor(partial: Uint8Array) {
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super("Encountered UnexpectedEof, data only partially read");
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this.name = this.constructor.name;
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this.partial = partial;
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}
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}
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/**
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* Result type returned by of {@linkcode BufReader.readLine}.
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*
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* @deprecated This will be removed in 1.0.0. Use the {@link https://developer.mozilla.org/en-US/docs/Web/API/Streams_API | Web Streams API} instead.
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*/
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export interface ReadLineResult {
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/** The line read */
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line: Uint8Array;
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/** `true if the end of the line has not been reached, `false` otherwise. */
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more: boolean;
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}
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/**
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* Implements buffering for a {@linkcode Reader} object.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const encoder = new TextEncoder();
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* const decoder = new TextDecoder();
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*
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* const reader = new BufReader(new Buffer(encoder.encode("hello world")));
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* const buf = new Uint8Array(11);
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* await reader.read(buf);
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* assertEquals(decoder.decode(buf), "hello world");
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* ```
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*
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* @deprecated This will be removed in 1.0.0. Use the {@link https://developer.mozilla.org/en-US/docs/Web/API/Streams_API | Web Streams API} instead.
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*/
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export class BufReader implements Reader {
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#buf!: Uint8Array;
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#rd!: Reader; // Reader provided by caller.
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#r = 0; // buf read position.
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#w = 0; // buf write position.
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#eof = false;
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/**
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* Returns a new {@linkcode BufReader} if `r` is not already one.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assert } from "@std/assert/assert";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello world"));
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* const bufReader = BufReader.create(reader);
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* assert(bufReader instanceof BufReader);
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* ```
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*
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* @param r The reader to read from.
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* @param size The size of the buffer.
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* @returns A new {@linkcode BufReader} if `r` is not already one.
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*/
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static create(r: Reader, size: number = DEFAULT_BUF_SIZE): BufReader {
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return r instanceof BufReader ? r : new BufReader(r, size);
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}
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/**
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* Constructs a new {@linkcode BufReader} for the given reader and buffer size.
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*
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* @param rd The reader to read from.
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* @param size The size of the buffer.
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*/
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constructor(rd: Reader, size: number = DEFAULT_BUF_SIZE) {
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if (size < MIN_BUF_SIZE) {
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size = MIN_BUF_SIZE;
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}
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this.#reset(new Uint8Array(size), rd);
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}
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/**
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* Returns the size of the underlying buffer in bytes.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello world"));
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* const bufReader = new BufReader(reader);
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*
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* assertEquals(bufReader.size(), 4096);
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* ```
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*
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* @returns The size of the underlying buffer in bytes.
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*/
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size(): number {
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return this.#buf.byteLength;
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}
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/**
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* Returns the number of bytes that can be read from the current buffer.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello world"));
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* const bufReader = new BufReader(reader);
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* await bufReader.read(new Uint8Array(5));
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* assertEquals(bufReader.buffered(), 6);
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* ```
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*
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* @returns Number of bytes that can be read from the buffer
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*/
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buffered(): number {
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return this.#w - this.#r;
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}
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// Reads a new chunk into the buffer.
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#fill = async () => {
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// Slide existing data to beginning.
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if (this.#r > 0) {
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this.#buf.copyWithin(0, this.#r, this.#w);
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this.#w -= this.#r;
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this.#r = 0;
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}
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if (this.#w >= this.#buf.byteLength) {
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throw new Error("Buffer full while filling");
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}
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// Read new data: try a limited number of times.
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for (let i = MAX_CONSECUTIVE_EMPTY_READS; i > 0; i--) {
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const rr = await this.#rd.read(this.#buf.subarray(this.#w));
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if (rr === null) {
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this.#eof = true;
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return;
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}
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this.#w += rr;
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if (rr > 0) {
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return;
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}
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}
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throw new Error(
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`No progress after ${MAX_CONSECUTIVE_EMPTY_READS} read() calls`,
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);
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};
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/**
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* Discards any buffered data, resets all state, and switches
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* the buffered reader to read from `r`.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello world"));
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* const bufReader = new BufReader(reader);
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* await bufReader.read(new Uint8Array(5));
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* bufReader.reset(reader);
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* assertEquals(bufReader.buffered(), 6);
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* ```
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*
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* @param r The reader to read from.
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*/
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reset(r: Reader) {
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this.#reset(this.#buf, r);
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}
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#reset = (buf: Uint8Array, rd: Reader) => {
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this.#buf = buf;
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this.#rd = rd;
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this.#eof = false;
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// this.lastByte = -1;
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// this.lastCharSize = -1;
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};
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/**
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* Reads data into `p`.
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*
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* The bytes are taken from at most one `read()` on the underlying `Reader`,
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* hence n may be less than `len(p)`.
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* To read exactly `len(p)` bytes, use `io.ReadFull(b, p)`.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello world"));
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* const bufReader = new BufReader(reader);
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* const buf = new Uint8Array(5);
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* await bufReader.read(buf);
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* assertEquals(new TextDecoder().decode(buf), "hello");
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* ```
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*
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* @param p The buffer to read data into.
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* @returns The number of bytes read into `p`.
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*/
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async read(p: Uint8Array): Promise<number | null> {
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let rr: number | null = p.byteLength;
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if (p.byteLength === 0) return rr;
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if (this.#r === this.#w) {
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if (p.byteLength >= this.#buf.byteLength) {
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// Large read, empty buffer.
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// Read directly into p to avoid copy.
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const rr = await this.#rd.read(p);
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// if (rr.nread > 0) {
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// this.lastByte = p[rr.nread - 1];
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// this.lastCharSize = -1;
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// }
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return rr;
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}
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// One read.
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// Do not use this.fill, which will loop.
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this.#r = 0;
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this.#w = 0;
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rr = await this.#rd.read(this.#buf);
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if (rr === 0 || rr === null) return rr;
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this.#w += rr;
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}
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// copy as much as we can
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const copied = copy(this.#buf.subarray(this.#r, this.#w), p, 0);
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this.#r += copied;
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// this.lastByte = this.buf[this.r - 1];
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// this.lastCharSize = -1;
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return copied;
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}
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/**
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* Reads exactly `p.length` bytes into `p`.
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*
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* If successful, `p` is returned.
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*
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* If the end of the underlying stream has been reached, and there are no more
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* bytes available in the buffer, `readFull()` returns `null` instead.
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*
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* An error is thrown if some bytes could be read, but not enough to fill `p`
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* entirely before the underlying stream reported an error or EOF. Any error
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* thrown will have a `partial` property that indicates the slice of the
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* buffer that has been successfully filled with data.
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*
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* Ported from https://golang.org/pkg/io/#ReadFull
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello world"));
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* const bufReader = new BufReader(reader);
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* const buf = new Uint8Array(5);
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* await bufReader.readFull(buf);
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* assertEquals(new TextDecoder().decode(buf), "hello");
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* ```
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*
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* @param p The buffer to read data into.
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* @returns The buffer `p` if the read is successful, `null` if the end of the
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* underlying stream has been reached, and there are no more bytes available in the buffer.
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*/
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async readFull(p: Uint8Array): Promise<Uint8Array | null> {
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let bytesRead = 0;
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while (bytesRead < p.length) {
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const rr = await this.read(p.subarray(bytesRead));
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if (rr === null) {
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if (bytesRead === 0) {
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return null;
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} else {
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throw new PartialReadError(p.subarray(0, bytesRead));
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}
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}
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bytesRead += rr;
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}
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return p;
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}
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/**
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* Returns the next byte ([0, 255]) or `null`.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello world"));
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* const bufReader = new BufReader(reader);
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* const byte = await bufReader.readByte();
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* assertEquals(byte, 104);
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* ```
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*
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* @returns The next byte ([0, 255]) or `null`.
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*/
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async readByte(): Promise<number | null> {
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while (this.#r === this.#w) {
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if (this.#eof) return null;
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await this.#fill(); // buffer is empty.
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}
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const c = this.#buf[this.#r]!;
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this.#r++;
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// this.lastByte = c;
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return c;
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}
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/**
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* Reads until the first occurrence of delim in the input,
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* returning a string containing the data up to and including the delimiter.
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* If ReadString encounters an error before finding a delimiter,
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* it returns the data read before the error and the error itself
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* (often `null`).
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* ReadString returns err !== null if and only if the returned data does not end
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* in delim.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello world"));
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* const bufReader = new BufReader(reader);
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* const str = await bufReader.readString(" ");
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* assertEquals(str, "hello ");
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*
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* const str2 = await bufReader.readString(" ");
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* assertEquals(str2, "world");
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* ```
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*
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* @param delim The delimiter to read until.
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* @returns The string containing the data up to and including the delimiter.
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*/
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async readString(delim: string): Promise<string | null> {
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if (delim.length !== 1) {
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throw new Error("Delimiter should be a single character");
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}
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const buffer = await this.readSlice(delim.charCodeAt(0));
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if (buffer === null) return null;
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return new TextDecoder().decode(buffer);
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}
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/**
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* A low-level line-reading primitive. Most callers should use
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* `readString('\n')` instead.
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*
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* `readLine()` tries to return a single line, not including the end-of-line
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* bytes. If the line was too long for the buffer then `more` is set and the
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* beginning of the line is returned. The rest of the line will be returned
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* from future calls. `more` will be false when returning the last fragment
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* of the line. The returned buffer is only valid until the next call to
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* `readLine()`.
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*
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* The text returned from this method does not include the line end ("\r\n" or
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* "\n").
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*
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* When the end of the underlying stream is reached, the final bytes in the
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* stream are returned. No indication or error is given if the input ends
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* without a final line end. When there are no more trailing bytes to read,
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* `readLine()` returns `null`.
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*
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* @example Usage
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* ```ts
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* import { BufReader, Buffer } from "@std/io";
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* import { assertEquals } from "@std/assert/equals";
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*
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* const reader = new Buffer(new TextEncoder().encode("hello\nworld"));
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* const bufReader = new BufReader(reader);
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* const line1 = await bufReader.readLine();
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* assertEquals(new TextDecoder().decode(line1!.line), "hello");
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* const line2 = await bufReader.readLine();
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* assertEquals(new TextDecoder().decode(line2!.line), "world");
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* ```
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*
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* @returns The line read.
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*/
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async readLine(): Promise<ReadLineResult | null> {
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let line: Uint8Array | null = null;
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try {
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line = await this.readSlice(LF);
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} catch (err) {
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// Don't throw if `readSlice()` failed with `BufferFullError`, instead we
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// just return whatever is available and set the `more` flag.
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if (!(err instanceof BufferFullError)) {
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throw err;
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}
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let partial = err.partial;
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// Handle the case where "\r\n" straddles the buffer.
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if (
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!this.#eof && partial &&
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partial.byteLength > 0 &&
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partial[partial.byteLength - 1] === CR
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) {
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// Put the '\r' back on buf and drop it from line.
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// Let the next call to ReadLine check for "\r\n".
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if (this.#r <= 0) {
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throw new Error("Tried to rewind past start of buffer");
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}
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this.#r--;
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partial = partial.subarray(0, partial.byteLength - 1);
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}
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if (partial) {
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return { line: partial, more: !this.#eof };
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}
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}
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if (line === null) {
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return null;
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}
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if (line.byteLength === 0) {
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return { line, more: false };
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}
|
|
|
|
if (line[line.byteLength - 1] === LF) {
|
|
let drop = 1;
|
|
if (line.byteLength > 1 && line[line.byteLength - 2] === CR) {
|
|
drop = 2;
|
|
}
|
|
line = line.subarray(0, line.byteLength - drop);
|
|
}
|
|
return { line, more: false };
|
|
}
|
|
|
|
/**
|
|
* Reads until the first occurrence of `delim` in the input,
|
|
* returning a slice pointing at the bytes in the buffer. The bytes stop
|
|
* being valid at the next read.
|
|
*
|
|
* If `readSlice()` encounters an error before finding a delimiter, or the
|
|
* buffer fills without finding a delimiter, it throws an error with a
|
|
* `partial` property that contains the entire buffer.
|
|
*
|
|
* If `readSlice()` encounters the end of the underlying stream and there are
|
|
* any bytes left in the buffer, the rest of the buffer is returned. In other
|
|
* words, EOF is always treated as a delimiter. Once the buffer is empty,
|
|
* it returns `null`.
|
|
*
|
|
* Because the data returned from `readSlice()` will be overwritten by the
|
|
* next I/O operation, most clients should use `readString()` instead.
|
|
*
|
|
* @example Usage
|
|
* ```ts
|
|
* import { BufReader, Buffer } from "@std/io";
|
|
* import { assertEquals } from "@std/assert/equals";
|
|
*
|
|
* const reader = new Buffer(new TextEncoder().encode("hello world"));
|
|
* const bufReader = new BufReader(reader);
|
|
* const slice = await bufReader.readSlice(0x20);
|
|
* assertEquals(new TextDecoder().decode(slice!), "hello ");
|
|
* ```
|
|
*
|
|
* @param delim The delimiter to read until.
|
|
* @returns A slice pointing at the bytes in the buffer.
|
|
*/
|
|
async readSlice(delim: number): Promise<Uint8Array | null> {
|
|
let s = 0; // search start index
|
|
let slice: Uint8Array | undefined;
|
|
|
|
while (true) {
|
|
// Search buffer.
|
|
let i = this.#buf.subarray(this.#r + s, this.#w).indexOf(delim);
|
|
if (i >= 0) {
|
|
i += s;
|
|
slice = this.#buf.subarray(this.#r, this.#r + i + 1);
|
|
this.#r += i + 1;
|
|
break;
|
|
}
|
|
|
|
// EOF?
|
|
if (this.#eof) {
|
|
if (this.#r === this.#w) {
|
|
return null;
|
|
}
|
|
slice = this.#buf.subarray(this.#r, this.#w);
|
|
this.#r = this.#w;
|
|
break;
|
|
}
|
|
|
|
// Buffer full?
|
|
if (this.buffered() >= this.#buf.byteLength) {
|
|
this.#r = this.#w;
|
|
// #4521 The internal buffer should not be reused across reads because it causes corruption of data.
|
|
const oldbuf = this.#buf;
|
|
const newbuf = this.#buf.slice(0);
|
|
this.#buf = newbuf;
|
|
throw new BufferFullError(oldbuf);
|
|
}
|
|
|
|
s = this.#w - this.#r; // do not rescan area we scanned before
|
|
|
|
// Buffer is not full.
|
|
await this.#fill();
|
|
}
|
|
|
|
// Handle last byte, if any.
|
|
// const i = slice.byteLength - 1;
|
|
// if (i >= 0) {
|
|
// this.lastByte = slice[i];
|
|
// this.lastCharSize = -1
|
|
// }
|
|
|
|
return slice;
|
|
}
|
|
|
|
/**
|
|
* Returns the next `n` bytes without advancing the reader. The
|
|
* bytes stop being valid at the next read call.
|
|
*
|
|
* When the end of the underlying stream is reached, but there are unread
|
|
* bytes left in the buffer, those bytes are returned. If there are no bytes
|
|
* left in the buffer, it returns `null`.
|
|
*
|
|
* If an error is encountered before `n` bytes are available, `peek()` throws
|
|
* an error with the `partial` property set to a slice of the buffer that
|
|
* contains the bytes that were available before the error occurred.
|
|
*
|
|
* @example Usage
|
|
* ```ts
|
|
* import { BufReader, Buffer } from "@std/io";
|
|
* import { assertEquals } from "@std/assert/equals";
|
|
*
|
|
* const reader = new Buffer(new TextEncoder().encode("hello world"));
|
|
* const bufReader = new BufReader(reader);
|
|
* const peeked = await bufReader.peek(5);
|
|
* assertEquals(new TextDecoder().decode(peeked!), "hello");
|
|
* ```
|
|
*
|
|
* @param n The number of bytes to peek.
|
|
* @returns The next `n` bytes without advancing the reader.
|
|
*/
|
|
async peek(n: number): Promise<Uint8Array | null> {
|
|
if (n < 0) {
|
|
throw new Error("Peek count cannot be negative");
|
|
}
|
|
|
|
let avail = this.#w - this.#r;
|
|
while (avail < n && avail < this.#buf.byteLength && !this.#eof) {
|
|
await this.#fill();
|
|
avail = this.#w - this.#r;
|
|
}
|
|
|
|
if (avail === 0 && this.#eof) {
|
|
return null;
|
|
} else if (avail < n && this.#eof) {
|
|
return this.#buf.subarray(this.#r, this.#r + avail);
|
|
} else if (avail < n) {
|
|
throw new BufferFullError(this.#buf.subarray(this.#r, this.#w));
|
|
}
|
|
|
|
return this.#buf.subarray(this.#r, this.#r + n);
|
|
}
|
|
}
|