video-pc/libs/Recorder/ring_buffer.h

#ifndef RING_BUFFER
#define RING_BUFFER

#include <stdio.h>
#include <stdlib.h>

#include <mutex>
#include <queue>
#include <atomic>

#include "error_define.h"
#include "log_helper.h"

namespace am {
template<typename T>
struct ring_frame
{
    T type;
    int len;
};

template<typename T>
class ring_buffer
{
public:
    ring_buffer(unsigned int size = 1920 * 1080 * 4 * 2, size_t max_frames = 1)  // 回到1帧最小延迟
    {
        _size = size;
        _buffer_size = size;  // 记录缓冲区大小
        _head = _tail = 0;
        _max_frames = max_frames;
        _dropped_frames.store(0, std::memory_order_relaxed);

        _buf = new uint8_t[size];
    }
    ~ring_buffer()
    {
        if (_buf)
            delete[] _buf;
    }

    void put(const void *data, int len, const T &type)
    {
        std::lock_guard<std::mutex> locker(_lock);

        // 智能丢帧策略：根据帧重要性决定是否丢弃
        if (_frames.size() >= _max_frames) {
            // 检查是否为关键帧或重要帧（这里简化处理）
            bool is_important_frame = (len > _buffer_size * 0.8); // 大帧通常更重要
            
            if (!is_important_frame && !_frames.empty()) {
                // 只丢弃非重要帧
                ring_frame<T> old_frame = _frames.front();
                _frames.pop();
                _tail = (_tail + old_frame.len) % _size;
                _dropped_frames.fetch_add(1, std::memory_order_relaxed);
            } else if (_frames.size() >= _max_frames * 2) {
                // 缓冲区严重积压时强制丢帧
                ring_frame<T> old_frame = _frames.front();
                _frames.pop();
                _tail = (_tail + old_frame.len) % _size;
                _dropped_frames.fetch_add(1, std::memory_order_relaxed);
            }
        }

        if (_head + len <= _size) {
            memcpy(_buf + _head, data, len);

            _head += len;
        } else if (_head + len > _size) {
            int remain = len - (_size - _head);
            if (len - remain > 0)
                memcpy(_buf + _head, data, len - remain);

            if (remain > 0)
                memcpy(_buf, (unsigned char *) data + len - remain, remain);

            _head = remain;
        }

        struct ring_frame<T> frame;
        frame.len = len;
        frame.type = type;

        _frames.push(frame);
    }

    int get(void *data, int len, T &type)
    {
        std::lock_guard<std::mutex> locker(_lock);

        int retLen = 0;

        if (_frames.size() <= 0) {
            retLen = 0;
            return retLen;
        }

        struct ring_frame<T> frame = _frames.front();
        _frames.pop();

        if (frame.len > len) {
            al_error("ringbuff::get need larger buffer");
            return 0;
        }

        type = frame.type;

        retLen = frame.len;

        if (_tail + frame.len <= _size) {
            memcpy(data, _buf + _tail, frame.len);

            _tail += frame.len;
        } else {
            int remain = frame.len - (_size - _tail);

            if (frame.len - remain > 0)
                memcpy(data, _buf + _tail, frame.len - remain);

            if (remain > 0)
                memcpy((unsigned char *) data + frame.len - remain, _buf, remain);

            _tail = remain;
        }

        return retLen;
    }

    // 添加缓冲区监控方法
    size_t get_pending_frames() const 
    {
        std::lock_guard<std::mutex> locker(_lock);
        return _frames.size();
    }
    
    bool is_buffer_full(float threshold = 0.8f) const 
    {
        std::lock_guard<std::mutex> locker(_lock);
        return _frames.size() >= (static_cast<size_t>(_max_frames * threshold));
    }

    // 配置与统计接口
    void set_max_frames(size_t max_frames)
    {
        std::lock_guard<std::mutex> locker(_lock);
        _max_frames = max_frames;
    }

    size_t max_frames() const { return _max_frames; }

    size_t dropped_frames() const { return _dropped_frames.load(std::memory_order_relaxed); }

    void reset_dropped_frames() { _dropped_frames.store(0, std::memory_order_relaxed); }

private:
    std::queue<ring_frame<T>> _frames;
    unsigned int _size, _head, _tail;
    unsigned int _buffer_size;  // 添加缓冲区大小记录

    uint8_t *_buf;

    mutable std::mutex _lock;
    std::atomic<size_t> _dropped_frames{0};
    size_t _max_frames{1};
};
} // namespace am
#endif