export default function GZheader() {
  /* true if compressed data believed to be text */
  this.text       = 0;
  /* modification time */
  this.time       = 0;
  /* extra flags (not used when writing a gzip file) */
  this.xflags     = 0;
  /* operating system */
  this.os         = 0;
  /* pointer to extra field or Z_NULL if none */
  this.extra      = null;
  /* extra field length (valid if extra != Z_NULL) */
  this.extra_len  = 0; // Actually, we don't need it in JS,
                       // but leave for few code modifications

  //
  // Setup limits is not necessary because in js we should not preallocate memory
  // for inflate use constant limit in 65536 bytes
  //

  /* space at extra (only when reading header) */
  // this.extra_max  = 0;
  /* pointer to zero-terminated file name or Z_NULL */
  this.name       = '';
  /* space at name (only when reading header) */
  // this.name_max   = 0;
  /* pointer to zero-terminated comment or Z_NULL */
  this.comment    = '';
  /* space at comment (only when reading header) */
  // this.comm_max   = 0;
  /* true if there was or will be a header crc */
  this.hcrc       = 0;
  /* true when done reading gzip header (not used when writing a gzip file) */
  this.done       = false;
}