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/*! * Adapted directly from https://github.com/brianc/node-buffer-writer * which is licensed as follows: * * The MIT License (MIT) * * * Permission is hereby granted, free of charge, to any person obtaining * a copy of this software and associated documentation files (the * 'Software'), to deal in the Software without restriction, including * without limitation the rights to use, copy, modify, merge, publish, * distribute, sublicense, and/or sell copies of the Software, and to * permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be * included in all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
import { copy } from "../deps.ts";import { readInt16BE, readInt32BE } from "../utils/utils.ts";
export class PacketReader {  #buffer: Uint8Array;  #decoder = new TextDecoder();  #offset = 0;
  constructor(buffer: Uint8Array) {    this.#buffer = buffer;  }
  readInt16(): number {    const value = readInt16BE(this.#buffer, this.#offset);    this.#offset += 2;    return value;  }
  readInt32(): number {    const value = readInt32BE(this.#buffer, this.#offset);    this.#offset += 4;    return value;  }
  readByte(): number {    return this.readBytes(1)[0];  }
  readBytes(length: number): Uint8Array {    const start = this.#offset;    const end = start + length;    const slice = this.#buffer.slice(start, end);    this.#offset = end;    return slice;  }
  readAllBytes(): Uint8Array {    const slice = this.#buffer.slice(this.#offset);    this.#offset = this.#buffer.length;    return slice;  }
  readString(length: number): string {    const bytes = this.readBytes(length);    return this.#decoder.decode(bytes);  }
  readCString(): string {    const start = this.#offset;    // find next null byte    const end = this.#buffer.indexOf(0, start);    const slice = this.#buffer.slice(start, end);    // add +1 for null byte    this.#offset = end + 1;    return this.#decoder.decode(slice);  }}
export class PacketWriter {  #buffer: Uint8Array;  #encoder = new TextEncoder();  #headerPosition: number;  #offset: number;  #size: number;
  constructor(size?: number) {    this.#size = size || 1024;    this.#buffer = new Uint8Array(this.#size + 5);    this.#offset = 5;    this.#headerPosition = 0;  }
  #ensure(size: number) {    const remaining = this.#buffer.length - this.#offset;    if (remaining < size) {      const oldBuffer = this.#buffer;      // exponential growth factor of around ~ 1.5      // https://stackoverflow.com/questions/2269063/#buffer-growth-strategy      const newSize = oldBuffer.length + (oldBuffer.length >> 1) + size;      this.#buffer = new Uint8Array(newSize);      copy(oldBuffer, this.#buffer);    }  }
  addInt32(num: number) {    this.#ensure(4);    this.#buffer[this.#offset++] = (num >>> 24) & 0xff;    this.#buffer[this.#offset++] = (num >>> 16) & 0xff;    this.#buffer[this.#offset++] = (num >>> 8) & 0xff;    this.#buffer[this.#offset++] = (num >>> 0) & 0xff;    return this;  }
  addInt16(num: number) {    this.#ensure(2);    this.#buffer[this.#offset++] = (num >>> 8) & 0xff;    this.#buffer[this.#offset++] = (num >>> 0) & 0xff;    return this;  }
  addCString(string?: string) {    // just write a 0 for empty or null strings    if (!string) {      this.#ensure(1);    } else {      const encodedStr = this.#encoder.encode(string);      this.#ensure(encodedStr.byteLength + 1); // +1 for null terminator      copy(encodedStr, this.#buffer, this.#offset);      this.#offset += encodedStr.byteLength;    }
    this.#buffer[this.#offset++] = 0; // null terminator    return this;  }
  addChar(c: string) {    if (c.length != 1) {      throw new Error("addChar requires single character strings");    }
    this.#ensure(1);    copy(this.#encoder.encode(c), this.#buffer, this.#offset);    this.#offset++;    return this;  }
  addString(string?: string) {    string = string || "";    const encodedStr = this.#encoder.encode(string);    this.#ensure(encodedStr.byteLength);    copy(encodedStr, this.#buffer, this.#offset);    this.#offset += encodedStr.byteLength;    return this;  }
  add(otherBuffer: Uint8Array) {    this.#ensure(otherBuffer.length);    copy(otherBuffer, this.#buffer, this.#offset);    this.#offset += otherBuffer.length;    return this;  }
  clear() {    this.#offset = 5;    this.#headerPosition = 0;  }
  // appends a header block to all the written data since the last  // subsequent header or to the beginning if there is only one data block  addHeader(code: number, last?: boolean) {    const origOffset = this.#offset;    this.#offset = this.#headerPosition;    this.#buffer[this.#offset++] = code;    // length is everything in this packet minus the code    this.addInt32(origOffset - (this.#headerPosition + 1));    // set next header position    this.#headerPosition = origOffset;    // make space for next header    this.#offset = origOffset;    if (!last) {      this.#ensure(5);      this.#offset += 5;    }    return this;  }
  join(code?: number) {    if (code) {      this.addHeader(code, true);    }    return this.#buffer.slice(code ? 0 : 5, this.#offset);  }
  flush(code?: number) {    const result = this.join(code);    this.clear();    return result;  }}