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// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.import { Buffer } from "../buffer.ts";import { ERR_INVALID_ARG_TYPE } from "../internal/errors.ts";import {  validateOffsetLengthRead,  validatePosition,} from "../internal/fs/utils.mjs";import { validateBuffer, validateInteger } from "../internal/validators.mjs";
type readOptions = {  buffer: Buffer | Uint8Array;  offset: number;  length: number;  position: number | null;};
type readSyncOptions = {  offset: number;  length: number;  position: number | null;};
type BinaryCallback = (  err: Error | null,  bytesRead: number | null,  data?: Buffer,) => void;type Callback = BinaryCallback;
export function read(fd: number, callback: Callback): void;export function read(  fd: number,  options: readOptions,  callback: Callback,): void;export function read(  fd: number,  buffer: Buffer | Uint8Array,  offset: number,  length: number,  position: number | null,  callback: Callback,): void;export function read(  fd: number,  optOrBufferOrCb?: Buffer | Uint8Array | readOptions | Callback,  offsetOrCallback?: number | Callback,  length?: number,  position?: number | null,  callback?: Callback,) {  let cb: Callback | undefined;  let offset = 0,    buffer: Buffer | Uint8Array;
  if (typeof fd !== "number") {    throw new ERR_INVALID_ARG_TYPE("fd", "number", fd);  }
  if (length == null) {    length = 0;  }
  if (typeof offsetOrCallback === "function") {    cb = offsetOrCallback;  } else if (typeof optOrBufferOrCb === "function") {    cb = optOrBufferOrCb;  } else {    offset = offsetOrCallback as number;    validateInteger(offset, "offset", 0);    cb = callback;  }
  if (    optOrBufferOrCb instanceof Buffer || optOrBufferOrCb instanceof Uint8Array  ) {    buffer = optOrBufferOrCb;  } else if (typeof optOrBufferOrCb === "function") {    offset = 0;    buffer = Buffer.alloc(16384);    length = buffer.byteLength;    position = null;  } else {    const opt = optOrBufferOrCb as readOptions;    if (      !(opt.buffer instanceof Buffer) && !(opt.buffer instanceof Uint8Array)    ) {      if (opt.buffer === null) {        // @ts-ignore: Intentionally create TypeError for passing test-fs-read.js#L87        length = opt.buffer.byteLength;      }      throw new ERR_INVALID_ARG_TYPE("buffer", [        "Buffer",        "TypedArray",        "DataView",      ], optOrBufferOrCb);    }    offset = opt.offset ?? 0;    buffer = opt.buffer ?? Buffer.alloc(16384);    length = opt.length ?? buffer.byteLength;    position = opt.position ?? null;  }
  if (position == null) {    position = -1;  }
  validatePosition(position);  validateOffsetLengthRead(offset, length, buffer.byteLength);
  if (!cb) throw new ERR_INVALID_ARG_TYPE("cb", "Callback", cb);
  (async () => {    try {      let nread: number | null;      if (typeof position === "number" && position >= 0) {        const currentPosition = await Deno.seek(fd, 0, Deno.SeekMode.Current);        // We use sync calls below to avoid being affected by others during        // these calls.        Deno.seekSync(fd, position, Deno.SeekMode.Start);        nread = Deno.readSync(fd, buffer);        Deno.seekSync(fd, currentPosition, Deno.SeekMode.Start);      } else {        nread = await Deno.read(fd, buffer);      }      cb(null, nread ?? 0, Buffer.from(buffer.buffer, offset, length));    } catch (error) {      cb(error as Error, null);    }  })();}
export function readSync(  fd: number,  buffer: Buffer | Uint8Array,  offset: number,  length: number,  position: number | null,): number;export function readSync(  fd: number,  buffer: Buffer | Uint8Array,  opt: readSyncOptions,): number;export function readSync(  fd: number,  buffer: Buffer | Uint8Array,  offsetOrOpt?: number | readSyncOptions,  length?: number,  position?: number | null,): number {  let offset = 0;
  if (typeof fd !== "number") {    throw new ERR_INVALID_ARG_TYPE("fd", "number", fd);  }
  validateBuffer(buffer);
  if (length == null) {    length = 0;  }
  if (typeof offsetOrOpt === "number") {    offset = offsetOrOpt;    validateInteger(offset, "offset", 0);  } else {    const opt = offsetOrOpt as readSyncOptions;    offset = opt.offset ?? 0;    length = opt.length ?? buffer.byteLength;    position = opt.position ?? null;  }
  if (position == null) {    position = -1;  }
  validatePosition(position);  validateOffsetLengthRead(offset, length, buffer.byteLength);
  let currentPosition = 0;  if (typeof position === "number" && position >= 0) {    currentPosition = Deno.seekSync(fd, 0, Deno.SeekMode.Current);    Deno.seekSync(fd, position, Deno.SeekMode.Start);  }
  const numberOfBytesRead = Deno.readSync(fd, buffer);
  if (typeof position === "number" && position >= 0) {    Deno.seekSync(fd, currentPosition, Deno.SeekMode.Start);  }
  return numberOfBytesRead ?? 0;}