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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 { copyBytes } from "./deps.ts";
export class PacketWriter {  private size: number;  private buffer: Uint8Array;  private offset: number;  private headerPosition: number;  private encoder = new TextEncoder();
  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);      copyBytes(this.buffer, oldBuffer);    }  }
  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      copyBytes(this.buffer, encodedStr, 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);    copyBytes(this.buffer, this.encoder.encode(c), this.offset);    this.offset++;    return this;  }
  addString(string?: string) {    string = string || "";    const encodedStr = this.encoder.encode(string);    this._ensure(encodedStr.byteLength);    copyBytes(this.buffer, encodedStr, this.offset);    this.offset += encodedStr.byteLength;    return this;  }
  add(otherBuffer: Uint8Array) {    this._ensure(otherBuffer.length);    copyBytes(this.buffer, otherBuffer, 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;  }}