ipa_data_serializer.h

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/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2020, Google Inc.
 *
 * Image Processing Algorithm data serializer
 */

#pragma once

#include <stdint.h>
#include <string.h>
#include <tuple>
#include <type_traits>
#include <vector>

#include <libcamera/base/flags.h>
#include <libcamera/base/log.h>

#include <libcamera/control_ids.h>
#include <libcamera/framebuffer.h>
#include <libcamera/geometry.h>

#include <libcamera/ipa/ipa_interface.h>

#include "libcamera/internal/control_serializer.h"

namespace libcamera {

LOG_DECLARE_CATEGORY(IPADataSerializer)

namespace {

template<typename T,
     std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
void appendPOD(std::vector<uint8_t> &vec, T val)
{
    constexpr size_t byteWidth = sizeof(val);
    vec.resize(vec.size() + byteWidth);
    memcpy(&*(vec.end() - byteWidth), &val, byteWidth);
}

template<typename T,
     std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
T readPOD(std::vector<uint8_t>::const_iterator it, size_t pos,
      std::vector<uint8_t>::const_iterator end)
{
    ASSERT(pos + it < end);

    T ret = 0;
    memcpy(&ret, &(*(it + pos)), sizeof(ret));

    return ret;
}

template<typename T,
     std::enable_if_t<std::is_arithmetic_v<T>> * = nullptr>
T readPOD(std::vector<uint8_t> &vec, size_t pos)
{
    return readPOD<T>(vec.cbegin(), pos, vec.end());
}

} /* namespace */

template<typename T>
class IPADataSerializer
{
public:
    static std::tuple<std::vector<uint8_t>, std::vector<SharedFD>>
    serialize(const T &data, ControlSerializer *cs = nullptr);

    static T deserialize(const std::vector<uint8_t> &data,
                 ControlSerializer *cs = nullptr);
    static T deserialize(std::vector<uint8_t>::const_iterator dataBegin,
                 std::vector<uint8_t>::const_iterator dataEnd,
                 ControlSerializer *cs = nullptr);

    static T deserialize(const std::vector<uint8_t> &data,
                 const std::vector<SharedFD> &fds,
                 ControlSerializer *cs = nullptr);
    static T deserialize(std::vector<uint8_t>::const_iterator dataBegin,
                 std::vector<uint8_t>::const_iterator dataEnd,
                 std::vector<SharedFD>::const_iterator fdsBegin,
                 std::vector<SharedFD>::const_iterator fdsEnd,
                 ControlSerializer *cs = nullptr);
};

#ifndef __DOXYGEN__

/*
 * Serialization format for vector of type V:
 *
 * 4 bytes - uint32_t Length of vector, in number of elements
 *
 * For every element in the vector:
 *
 * 4 bytes - uint32_t Size of element, in bytes
 * 4 bytes - uint32_t Number of fds for the element
 * X bytes - Serialized element
 *
 * \todo Support elements that are references
 */
template<typename V>
class IPADataSerializer<std::vector<V>>
{
public:
    static std::tuple<std::vector<uint8_t>, std::vector<SharedFD>>
    serialize(const std::vector<V> &data, ControlSerializer *cs = nullptr)
    {
        std::vector<uint8_t> dataVec;
        std::vector<SharedFD> fdsVec;

        /* Serialize the length. */
        uint32_t vecLen = data.size();
        appendPOD<uint32_t>(dataVec, vecLen);

        /* Serialize the members. */
        for (auto const &it : data) {
            std::vector<uint8_t> dvec;
            std::vector<SharedFD> fvec;

            std::tie(dvec, fvec) =
                IPADataSerializer<V>::serialize(it, cs);

            appendPOD<uint32_t>(dataVec, dvec.size());
            appendPOD<uint32_t>(dataVec, fvec.size());

            dataVec.insert(dataVec.end(), dvec.begin(), dvec.end());
            fdsVec.insert(fdsVec.end(), fvec.begin(), fvec.end());
        }

        return { dataVec, fdsVec };
    }

    static std::vector<V> deserialize(std::vector<uint8_t> &data, ControlSerializer *cs = nullptr)
    {
        return deserialize(data.cbegin(), data.cend(), cs);
    }

    static std::vector<V> deserialize(std::vector<uint8_t>::const_iterator dataBegin,
                      std::vector<uint8_t>::const_iterator dataEnd,
                      ControlSerializer *cs = nullptr)
    {
        std::vector<SharedFD> fds;
        return deserialize(dataBegin, dataEnd, fds.cbegin(), fds.cend(), cs);
    }

    static std::vector<V> deserialize(std::vector<uint8_t> &data, std::vector<SharedFD> &fds,
                      ControlSerializer *cs = nullptr)
    {
        return deserialize(data.cbegin(), data.cend(), fds.cbegin(), fds.cend(), cs);
    }

    static std::vector<V> deserialize(std::vector<uint8_t>::const_iterator dataBegin,
                      std::vector<uint8_t>::const_iterator dataEnd,
                      std::vector<SharedFD>::const_iterator fdsBegin,
                      [[maybe_unused]] std::vector<SharedFD>::const_iterator fdsEnd,
                      ControlSerializer *cs = nullptr)
    {
        uint32_t vecLen = readPOD<uint32_t>(dataBegin, 0, dataEnd);
        std::vector<V> ret(vecLen);

        std::vector<uint8_t>::const_iterator dataIter = dataBegin + 4;
        std::vector<SharedFD>::const_iterator fdIter = fdsBegin;
        for (uint32_t i = 0; i < vecLen; i++) {
            uint32_t sizeofData = readPOD<uint32_t>(dataIter, 0, dataEnd);
            uint32_t sizeofFds = readPOD<uint32_t>(dataIter, 4, dataEnd);
            dataIter += 8;

            ret[i] = IPADataSerializer<V>::deserialize(dataIter,
                                   dataIter + sizeofData,
                                   fdIter,
                                   fdIter + sizeofFds,
                                   cs);

            dataIter += sizeofData;
            fdIter += sizeofFds;
        }

        return ret;
    }
};

/*
 * Serialization format for map of key type K and value type V:
 *
 * 4 bytes - uint32_t Length of map, in number of pairs
 *
 * For every pair in the map:
 *
 * 4 bytes - uint32_t Size of key, in bytes
 * 4 bytes - uint32_t Number of fds for the key
 * X bytes - Serialized key
 * 4 bytes - uint32_t Size of value, in bytes
 * 4 bytes - uint32_t Number of fds for the value
 * X bytes - Serialized value
 *
 * \todo Support keys or values that are references
 */
template<typename K, typename V>
class IPADataSerializer<std::map<K, V>>
{
public:
    static std::tuple<std::vector<uint8_t>, std::vector<SharedFD>>
    serialize(const std::map<K, V> &data, ControlSerializer *cs = nullptr)
    {
        std::vector<uint8_t> dataVec;
        std::vector<SharedFD> fdsVec;

        /* Serialize the length. */
        uint32_t mapLen = data.size();
        appendPOD<uint32_t>(dataVec, mapLen);

        /* Serialize the members. */
        for (auto const &it : data) {
            std::vector<uint8_t> dvec;
            std::vector<SharedFD> fvec;

            std::tie(dvec, fvec) =
                IPADataSerializer<K>::serialize(it.first, cs);

            appendPOD<uint32_t>(dataVec, dvec.size());
            appendPOD<uint32_t>(dataVec, fvec.size());

            dataVec.insert(dataVec.end(), dvec.begin(), dvec.end());
            fdsVec.insert(fdsVec.end(), fvec.begin(), fvec.end());

            std::tie(dvec, fvec) =
                IPADataSerializer<V>::serialize(it.second, cs);

            appendPOD<uint32_t>(dataVec, dvec.size());
            appendPOD<uint32_t>(dataVec, fvec.size());

            dataVec.insert(dataVec.end(), dvec.begin(), dvec.end());
            fdsVec.insert(fdsVec.end(), fvec.begin(), fvec.end());
        }

        return { dataVec, fdsVec };
    }

    static std::map<K, V> deserialize(std::vector<uint8_t> &data, ControlSerializer *cs = nullptr)
    {
        return deserialize(data.cbegin(), data.cend(), cs);
    }

    static std::map<K, V> deserialize(std::vector<uint8_t>::const_iterator dataBegin,
                      std::vector<uint8_t>::const_iterator dataEnd,
                      ControlSerializer *cs = nullptr)
    {
        std::vector<SharedFD> fds;
        return deserialize(dataBegin, dataEnd, fds.cbegin(), fds.cend(), cs);
    }

    static std::map<K, V> deserialize(std::vector<uint8_t> &data, std::vector<SharedFD> &fds,
                      ControlSerializer *cs = nullptr)
    {
        return deserialize(data.cbegin(), data.cend(), fds.cbegin(), fds.cend(), cs);
    }

    static std::map<K, V> deserialize(std::vector<uint8_t>::const_iterator dataBegin,
                      std::vector<uint8_t>::const_iterator dataEnd,
                      std::vector<SharedFD>::const_iterator fdsBegin,
                      [[maybe_unused]] std::vector<SharedFD>::const_iterator fdsEnd,
                      ControlSerializer *cs = nullptr)
    {
        std::map<K, V> ret;

        uint32_t mapLen = readPOD<uint32_t>(dataBegin, 0, dataEnd);

        std::vector<uint8_t>::const_iterator dataIter = dataBegin + 4;
        std::vector<SharedFD>::const_iterator fdIter = fdsBegin;
        for (uint32_t i = 0; i < mapLen; i++) {
            uint32_t sizeofData = readPOD<uint32_t>(dataIter, 0, dataEnd);
            uint32_t sizeofFds = readPOD<uint32_t>(dataIter, 4, dataEnd);
            dataIter += 8;

            K key = IPADataSerializer<K>::deserialize(dataIter,
                                  dataIter + sizeofData,
                                  fdIter,
                                  fdIter + sizeofFds,
                                  cs);

            dataIter += sizeofData;
            fdIter += sizeofFds;
            sizeofData = readPOD<uint32_t>(dataIter, 0, dataEnd);
            sizeofFds = readPOD<uint32_t>(dataIter, 4, dataEnd);
            dataIter += 8;

            const V value = IPADataSerializer<V>::deserialize(dataIter,
                                      dataIter + sizeofData,
                                      fdIter,
                                      fdIter + sizeofFds,
                                      cs);
            ret.insert({ key, value });

            dataIter += sizeofData;
            fdIter += sizeofFds;
        }

        return ret;
    }
};

/* Serialization format for Flags is same as for PODs */
template<typename E>
class IPADataSerializer<Flags<E>>
{
public:
    static std::tuple<std::vector<uint8_t>, std::vector<SharedFD>>
    serialize(const Flags<E> &data, [[maybe_unused]] ControlSerializer *cs = nullptr)
    {
        std::vector<uint8_t> dataVec;
        dataVec.reserve(sizeof(Flags<E>));
        appendPOD<uint32_t>(dataVec, static_cast<typename Flags<E>::Type>(data));

        return { dataVec, {} };
    }

    static Flags<E> deserialize(std::vector<uint8_t> &data,
                    [[maybe_unused]] ControlSerializer *cs = nullptr)
    {
        return deserialize(data.cbegin(), data.cend());
    }

    static Flags<E> deserialize(std::vector<uint8_t>::const_iterator dataBegin,
                    std::vector<uint8_t>::const_iterator dataEnd,
                    [[maybe_unused]] ControlSerializer *cs = nullptr)
    {
        return Flags<E>{ static_cast<E>(readPOD<uint32_t>(dataBegin, 0, dataEnd)) };
    }

    static Flags<E> deserialize(std::vector<uint8_t> &data,
                    [[maybe_unused]] std::vector<SharedFD> &fds,
                    [[maybe_unused]] ControlSerializer *cs = nullptr)
    {
        return deserialize(data.cbegin(), data.cend());
    }

    static Flags<E> deserialize(std::vector<uint8_t>::const_iterator dataBegin,
                    std::vector<uint8_t>::const_iterator dataEnd,
                    [[maybe_unused]] std::vector<SharedFD>::const_iterator fdsBegin,
                    [[maybe_unused]] std::vector<SharedFD>::const_iterator fdsEnd,
                    [[maybe_unused]] ControlSerializer *cs = nullptr)
    {
        return deserialize(dataBegin, dataEnd);
    }
};

#endif /* __DOXYGEN__ */

} /* namespace libcamera */