Method write

lib/protocol/SFTP.js:422–497

(handle, buf, off, len, position, cb)

    this.read(handle, buf, off, len, position, cb);
  }
  write(handle, buf, off, len, position, cb) {
    if (this.server)
      throw new Error('Client-only method called in server mode');

    if (!Buffer.isBuffer(handle))
      throw new Error('handle is not a Buffer');
    if (!Buffer.isBuffer(buf))
      throw new Error('buffer is not a Buffer');
    if (off > buf.length)
      throw new Error('offset is out of bounds');
    if (off + len > buf.length)
      throw new Error('length extends beyond buffer');
    if (position === null)
      throw new Error('null position currently unsupported');

    if (!len) {
      cb && process.nextTick(cb, undefined, 0);
      return;
    }

    const maxDataLen = this._maxWriteLen;
    const overflow = Math.max(len - maxDataLen, 0);
    const origPosition = position;

    if (overflow)
      len = maxDataLen;

    /*
      uint32     id
      string     handle
      uint64     offset
      string     data
    */
    const handleLen = handle.length;
    let p = 9;
    const out = Buffer.allocUnsafe(4 + 1 + 4 + 4 + handleLen + 8 + 4 + len);

    writeUInt32BE(out, out.length - 4, 0);
    out[4] = REQUEST.WRITE;
    const reqid = this._writeReqid = (this._writeReqid + 1) & MAX_REQID;
    writeUInt32BE(out, reqid, 5);

    writeUInt32BE(out, handleLen, p);
    out.set(handle, p += 4);
    p += handleLen;
    for (let i = 7; i >= 0; --i) {
      out[p + i] = position & 0xFF;
      position /= 256;
    }
    writeUInt32BE(out, len, p += 8);
    bufferCopy(buf, out, off, off + len, p += 4);

    this._requests[reqid] = {
      cb: (err) => {
        if (err) {
          if (typeof cb === 'function')
            cb(err);
        } else if (overflow) {