Function makeBufferParser

lib/protocol/utils.js:37–139

()

}

function makeBufferParser() {
  let pos = 0;
  let buffer;

  const self = {
    init: (buf, start) => {
      buffer = buf;
      pos = (typeof start === 'number' ? start : 0);
    },
    pos: () => pos,
    length: () => (buffer ? buffer.length : 0),
    avail: () => (buffer && pos < buffer.length ? buffer.length - pos : 0),
    clear: () => {
      buffer = undefined;
    },
    readUInt32BE: () => {
      if (!buffer || pos + 3 >= buffer.length)
        return;
      return (buffer[pos++] * 16777216)
             + (buffer[pos++] * 65536)
             + (buffer[pos++] * 256)
             + buffer[pos++];
    },
    readUInt64BE: (behavior) => {
      if (!buffer || pos + 7 >= buffer.length)
        return;
      switch (behavior) {
        case 'always':
          return BigInt(`0x${buffer.hexSlice(pos, pos += 8)}`);
        case 'maybe':
          if (buffer[pos] > 0x1F)
            return BigInt(`0x${buffer.hexSlice(pos, pos += 8)}`);
          // FALLTHROUGH
        default:
          return (buffer[pos++] * 72057594037927940)
                 + (buffer[pos++] * 281474976710656)
                 + (buffer[pos++] * 1099511627776)
                 + (buffer[pos++] * 4294967296)
                 + (buffer[pos++] * 16777216)
                 + (buffer[pos++] * 65536)
                 + (buffer[pos++] * 256)
                 + buffer[pos++];
      }
    },
    skip: (n) => {
      if (buffer && n > 0)
        pos += n;
    },
    skipString: () => {
      const len = self.readUInt32BE();
      if (len === undefined)
        return;
      pos += len;
      return (pos <= buffer.length ? len : undefined);
    },
    readByte: () => {
      if (buffer && pos < buffer.length)
        return buffer[pos++];