lib/wlan/common/tim_element.cpp

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <wlan/common/element_splitter.h>
#include <wlan/common/tim_element.h>

namespace wlan {
namespace common {

// TODO(hahnr): Support dot11MultiBSSIDActivated is true.
bool IsTrafficBuffered(uint16_t aid,
                       const TimHeader& tim_hdr,
                       Span<const uint8_t> bitmap) {
    size_t n1 = tim_hdr.bmp_ctrl.offset() * 2;

    size_t octet = aid / 8;
    // No traffic buffered for aid since it's not in the partial bitmap
    if (octet < n1 || octet - n1 >= bitmap.size()) return false;

    // Traffic might be buffered for aid
    return bitmap[octet - n1] & (1 << (aid % 8));
}

std::optional<ParsedTim> FindAndParseTim(Span<const uint8_t> ies) {
    auto splitter = common::ElementSplitter { ies };
    auto it = std::find_if(splitter.begin(), splitter.end(),
        [](auto elem) {
            return std::get<element_id::ElementId>(elem) == element_id::kTim;
        });

    if (it == splitter.end()) {
        return {};
    }

    return common::ParseTim(std::get<1>(*it));
}

} // namespace common
} // namespace wlan