lora_plug/serial_module_bk.c

#define PY_SSIZE_T_CLEAN
#include <Python.h>
#include <stdint.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <zlib.h> // 引入 zlib 库
#include <fec.h>  // 引入 libfec 库
#include "hx_serial.h"
#include "hx_ringbuffer.h"

// #define USE_FEC

#ifdef USE_FEC
#define FEC_SIZE 32 // 前向纠错冗余数据大小
#else
#define FEC_SIZE 0 // 前向纠错冗余数据大小
#endif
#define FRAME_HEADER 0xAA55                                             // 帧头
#define FRAME_SIZE (240)                                                // 每帧大小
#define HEADER_SIZE (4)                                                 // 帧头 + 帧序号 + 数据长度
#define CHECKSUM_SIZE (4)                                               // CRC32 校验和大小（4 字节）
#define DATA_SIZE (FRAME_SIZE - HEADER_SIZE - CHECKSUM_SIZE - FEC_SIZE) // 数据段大小
#define RING_BUFFER_SIZE (1024 * 10)                                    // 环形缓冲区大小 - default 10KB

// 全局变量：串口设备和发送缓冲区
static by_serial_t serial_port;
static by_ringbuf_t ring_buffer;
static uint8_t send_buffer[FRAME_SIZE];
static uint8_t send_buffer_test[FRAME_SIZE];
static uint8_t frame_counter = 0;
static uint8_t data_len = 0;

// 计算 CRC32 校验和
uint32_t calculate_crc32(const uint8_t *data, size_t length) {
    return crc32(0, data, length);
}

// 前向纠错编码
void fec_encode(uint8_t *data, size_t data_length, uint8_t *fec_data) {
    encode_rs_8(data, fec_data, 0);
}

// 前向纠错解码
int fec_decode(uint8_t *data, size_t data_length, uint8_t *fec_data) {
    return decode_rs_8(data, (int *)fec_data, 0, 0);
}

// 解析一帧数据
int parse_frame(by_ringbuf_t *ringbuf, uint8_t *output_data, int *output_len) {
    uint8_t frame[FRAME_SIZE];
    int available_data = by_ringbuf_available_data(ringbuf);

    // 检查是否有足够的数据解析一帧
    if (available_data < HEADER_SIZE + CHECKSUM_SIZE + FEC_SIZE) {
        return -1; // 数据不足，无法解析
    }

    // 查找帧头
    uint16_t header = FRAME_HEADER;
    int header_pos = by_ringbuf_find(ringbuf, (uint8_t *)&header, 2);
    if (header_pos < 0) {
        return -1; // 没有找到帧头
    }

    // 弹出帧头之前的数据
    by_ringbuf_pop(ringbuf, frame, header_pos);

    // 检查是否有足够的数据解析一帧
    if (by_ringbuf_available_data(ringbuf) < FRAME_SIZE) {
        return -1; // 数据不足，无法解析
    }

    // 读取帧数据
    by_ringbuf_pop(ringbuf, frame, FRAME_SIZE);

    // 解析帧序号、有效数据长度、数据段和 CRC32
    uint8_t seq = frame[2];
    uint8_t valid_data_len = frame[2 + 1];
    uint8_t *data_segment = &frame[2 + 1 + 1];
    uint32_t received_crc = *(uint32_t *)&frame[2 + 1 + 1 + DATA_SIZE];

    printf("Received frame: %d, valid_data_len: %d, received_crc: %08X\n", seq, valid_data_len, received_crc);

    for(uint8_t i = 0; i < FRAME_SIZE; i++) {
        printf("%02X ", frame[i]);
    }

    printf("\n");

    // 计算 CRC32 校验
    // uint32_t calculated_crc = calculate_crc32(data_segment, valid_data_len);
    uint32_t calculated_crc = calculate_crc32(frame, HEADER_SIZE + DATA_SIZE + FEC_SIZE);
    if (received_crc != calculated_crc) {
        printf("CRC mismatch! Expected: %08X, Received: %08X\n", calculated_crc, received_crc);
        return -1; // CRC 校验失败，丢弃该帧
    }

    // 将有效数据拼接到输出缓冲区
    memcpy(&output_data[*output_len], data_segment, valid_data_len);
    *output_len += valid_data_len;

    // 判断是否为最后一帧
    if (valid_data_len < DATA_SIZE) {
        printf("Received last frame!\n");
        return 1; // 最后一帧，解析完成
    }

    return 0; // 成功解析一帧，但可能还有更多帧
}

// 边读取边解析串口数据
int parse_serial_data(by_serial_t *serial_port, by_ringbuf_t *ringbuf, uint8_t *output_data, int *output_len) {
    uint8_t buffer[FRAME_SIZE];
    int ret;

    // 从串口读取数据到环形缓冲区
    ret = by_serial_read(serial_port, buffer, FRAME_SIZE);
    if (ret > 0) {
        by_ringbuf_append(ringbuf, buffer, ret);
    }

    // 尝试解析环形缓冲区中的数据
    while (1) {
        int parse_result = parse_frame(ringbuf, output_data, output_len);
        if (parse_result == 1) {
            return 0; // 解析完成
        } else if (parse_result == -1) {
            break; // 数据不足或解析失败，退出循环
        }
    }

    return -1; // 未找到完整帧
}

// 初始化串口
static PyObject *serial_init(PyObject *self, PyObject *args) {
    const char *dev_name;

    if (!PyArg_ParseTuple(args, "s", &dev_name)) {
        return NULL;
    }

    if (by_serial_init(&serial_port, dev_name) != 0) {
        PyErr_SetString(PyExc_IOError, "Failed to initialize serial port");
        return NULL;
    }

    // 初始化环形缓冲区
    if (by_ringbuf_init(&ring_buffer, RING_BUFFER_SIZE) != 0) {
        PyErr_SetString(PyExc_IOError, "Failed to initialize ring buffer");
        return NULL;
    }

    frame_counter = 0; // 重置帧计数器
    Py_RETURN_NONE;
}

// 发送数据
static PyObject *serial_send(PyObject *self, PyObject *args) {
    const char *data;
    Py_ssize_t length;

    if (!PyArg_ParseTuple(args, "s#", &data, &length)) {
        return NULL;
    }

    printf("Send data len = %ld\n", length);

    size_t offset = 0;
    uint8_t idx = 0;
    while (offset < length) {
        memset(send_buffer, 0, FRAME_SIZE);

        // 构造帧头
        uint16_t header = FRAME_HEADER;
        memcpy(send_buffer, &header, 2);

        // 构造帧序号
        memcpy(send_buffer + 2, &frame_counter, 1);

        // 构造数据长度
        if (length - offset > DATA_SIZE) {
            data_len = DATA_SIZE;
        } else {
            data_len = length - offset;
        }
        memcpy(send_buffer + 3, &data_len, 1);

        // 拷贝该帧对应数据段
        memcpy(send_buffer + HEADER_SIZE, data + offset, data_len);

#ifdef USE_FEC
        // 将 FEC 数据附加到帧中
        memcpy(send_buffer + HEADER_SIZE + DATA_SIZE, fec_data, 32);
#endif

        // 计算 CRC32 校验和
        uint32_t crc = calculate_crc32(send_buffer, HEADER_SIZE + DATA_SIZE + FEC_SIZE);
        memcpy(send_buffer + HEADER_SIZE + DATA_SIZE + FEC_SIZE, &crc, CHECKSUM_SIZE);

        for(uint8_t i = 0; i < FRAME_SIZE; i++) {
            printf("%02x ", send_buffer[i]);
        }

        // 发送帧
        if (by_serial_write(&serial_port, (const char *)send_buffer, FRAME_SIZE) != 0) {
            PyErr_SetString(PyExc_IOError, "Failed to send data over serial port");
            return NULL;
        }

        offset += DATA_SIZE;
        frame_counter++;

        printf("* frame [%d]\n", frame_counter);

        // usleep(50000);
        usleep(80000);
    }

    frame_counter = 0;

    printf("****************\n");

    Py_RETURN_NONE;
}

// 接收数据
static PyObject *serial_receive(PyObject *self, PyObject *args) {
    uint8_t output_data[8192];
    int output_len = 0;
    int timeout = 5000; // 超时时间，单位为毫秒
    int elapsed_time = 0;

    // TODO 增加当接收新帧时的处理
    while (elapsed_time < timeout) {
        if (parse_serial_data(&serial_port, &ring_buffer, output_data, &output_len) == 0) {
            // 返回解析后的数据
            printf("Parsed data length: %d\n", output_len);
            return Py_BuildValue("y#", output_data, output_len);
        }
        usleep(1000); // 等待 1 毫秒
        elapsed_time += 1;
    }

    // 超时未接收到完整帧
    PyErr_SetString(PyExc_TimeoutError, "Timeout while waiting for data");
    return NULL;
}

// 模块方法表
static PyMethodDef SerialMethods[] = {
    {"init", serial_init, METH_VARARGS, "Initialize serial port"},
    {"send", serial_send, METH_VARARGS, "Send data over serial port"},
    {"receive", serial_receive, METH_VARARGS, "Receive data from serial port"},
    {NULL, NULL, 0, NULL}};

// 模块定义
static struct PyModuleDef serialmodule = {
    PyModuleDef_HEAD_INIT,
    "serial_module",
    NULL,
    -1,
    SerialMethods};

// 模块初始化函数
PyMODINIT_FUNC PyInit_serial_module(void) {
    return PyModule_Create(&serialmodule);
}