v4l2_stats.h

/* SPDX-License-Identifier: LGPL-2.1-or-later */
/*
 * Copyright (C) 2026, Ideas On Board
 *
 * V4L2 ISP Statistics
 */
 
#pragma once
 
#include <map>
#include <span>
#include <stdint.h>
 
#include <linux/media/v4l2-isp.h>
 
namespace libcamera {
 
namespace ipa {
 
class V4L2StatsBase
{
public:
    V4L2StatsBase(std::span<uint8_t> data, unsigned int version);
 
    std::span<const uint8_t> block(unsigned int blockType, size_t blockSize) const;
    constexpr explicit operator bool()
    {
        return valid_;
    }
 
private:
    std::map<uint16_t, std::span<const uint8_t>> cache_;
    std::span<uint8_t> data_;
    bool valid_;
};
 
template<typename Traits>
class V4L2Stats : public V4L2StatsBase
{
public:
    static_assert(std::is_same_v<std::underlying_type_t<typename Traits::id_type>, uint16_t>);
 
    V4L2Stats(std::span<uint8_t> data, unsigned int version)
        : V4L2StatsBase(data, version)
    {
    }
 
    template<typename Traits::id_type Id>
    const typename Traits::template id_to_details<Id>::type *
    block() const
    {
        using Details = typename Traits::template id_to_details<Id>;
 
        using Type = typename Details::type;
        constexpr auto kernelId = Details::blockType;
 
        auto data = V4L2StatsBase::block(kernelId, sizeof(Type));
 
        return data.size() > 0 ?
               reinterpret_cast<const Type *>(data.data()) : nullptr;
    }
};
 
} /* namespace ipa */
 
} /* namespace libcamera */