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/// import
import { Buffer } from "node:buffer";
/// util
import * as types from "./utility/types.ts";


/// export
export class TypeBitmap {  decodeBytes = 0;  encodeBytes = 0;
  decode(buf, offset?, length?) {    if (!offset)      offset = 0;
    if (!length)      length = 0;
    const oldOffset = offset;    const typelist: Array<string> = [];
    while (offset - oldOffset < length) {      const window = buf.readUInt8(offset);      offset += 1;      const windowLength = buf.readUInt8(offset);      offset += 1;
      for (let i = 0; i < windowLength; i++) {        const b = buf.readUInt8(offset + i);
        for (let j = 0; j < 8; j++) {          if (b & (1 << (7 - j))) {            const typeid = types.toString((window << 8) | (i << 3) | j);            typelist.push(typeid);          }        }      }
      offset += windowLength;    }
    this.decodeBytes = offset - oldOffset;    return typelist;  }
  encode(typelist, buf?, offset?) {    if (!buf)      buf = Buffer.alloc(this.encodingLength(typelist));
    if (!offset)      offset = 0;
    const oldOffset = offset;    const typesByWindow: unknown[] = [];    let i;
    for (i = 0; i < typelist.length; i++) {      const typeid = types.toType(typelist[i]);
      if (typesByWindow[typeid >> 8] === undefined)        typesByWindow[typeid >> 8] = [];
      (typesByWindow[typeid >> 8] as number[])[(typeid >> 3) & 0x1F] |= 1 << (7 - (typeid & 0x7));    }
    for (i = 0; i < typesByWindow.length; i++) {      if (typesByWindow[i] !== undefined) {        const windowBuf = Buffer.from((typesByWindow[i] as number[]));
        buf.writeUInt8(i, offset);        offset += 1;        buf.writeUInt8(windowBuf.length, offset);        offset += 1;        windowBuf.copy(buf, offset);        offset += windowBuf.length;      }    }
    this.encodeBytes = offset - oldOffset;    return buf;  }
  encodingLength(typelist) {    const extents: Array<number> = [];    let i;    let len = 0;
    for (i = 0; i < typelist.length; i++) {      const typeid = types.toType(typelist[i]);      extents[typeid >> 8] = Math.max(extents[typeid >> 8] || 0, typeid & 0xFF);    }
    for (i = 0; i < extents.length; i++) {      if (extents[i] !== undefined)        len += 2 + Math.ceil((extents[i] + 1) / 8);    }
    return len;  }}