Method parse_range_and_compare

src/proxy/http/HttpSM.cc:4666–4860

* range entry valid [a,b] (a >= 0 and b >= 0 and a <= b) * HttpTransact::RANGE_NONE if the content length of cached copy is zero or * no range entry * HttpTransact::RANGE_NOT_SATISFIABLE iff all range entries are valid but * none overlap the current extent of the cached copy * HttpTransact::RANGE_NOT_HANDLED if out-of-order Range entries or * the cached copy`s content_length is INT64_MAX (e.

 * in order (remove the entries that not overlap the extent of cache copy)
 */
void
HttpSM::parse_range_and_compare(MIMEField *field, int64_t content_length)
{
  int          prev_good_range = -1;
  const char  *value;
  int          value_len;
  int          n_values;
  int          nr          = 0; // number of valid ranges, also index to range array.
  int          not_satisfy = 0;
  HdrCsvIter   csv;
  const char  *s, *e, *tmp;
  RangeRecord *ranges = nullptr;
  int64_t      start, end;

  ink_assert(field != nullptr && t_state.range_setup == HttpTransact::RANGE_NONE && t_state.ranges == nullptr);

  if (content_length <= 0) {
    return;
  }

  // ToDo: Can this really happen?
  if (content_length == INT64_MAX) {
    t_state.range_setup = HttpTransact::RANGE_NOT_HANDLED;
    return;
  }

  if (parse_range_done) {
    SMDbg(dbg_ctl_http_range, "parse_range already done, t_state.range_setup %d", t_state.range_setup);
    return;
  }
  parse_range_done = true;

  n_values = 0;
  value    = csv.get_first(field, &value_len);
  while (value) {
    ++n_values;
    value = csv.get_next(&value_len);
  }

  value = csv.get_first(field, &value_len);
  if (n_values <= 0 || ptr_len_ncmp(value, value_len, "bytes=", 6)) {
    return;
  }

  ranges     = new RangeRecord[n_values];
  value     += 6; // skip leading 'bytes='
  value_len -= 6;

  // assume range_in_cache
  t_state.range_in_cache = true;

  for (; value; value = csv.get_next(&value_len)) {
    if (!(tmp = static_cast<const char *>(memchr(value, '-', value_len)))) {
      t_state.range_setup = HttpTransact::RANGE_NONE;
      goto Lfaild;
    }

    // process start value