Is there a way to simulate a struct with a array?

Hello friends?

I need to implement some code I have done in C, and conver it to matlab. Can someone help me to simulate the following struct in matlab array?

typedef struct _RTC_C_Calendar
{
    uint32_t seconds;
    uint32_t minutes;
    uint32_t hours;
    uint32_t dayOfWeek;
    uint32_t dayOfmonth;
    uint32_t month;
    uint32_t year;
} RTC_C_Calendar;   // 28 bytes

struct long_byte {
    union {
        uint32_t val;
        uint8_t id[4];
    };
};

Answer 1

[Walter Roberson]

RTC_C_Calendar = zeros(Rows, 7,'uint32');

Now create variable names like dayOfWeek = 4;

and then you can index RTC_C_CALENDAR(row, dayOfWeek) and then the rest of your code does not need to know what the order of the fields is.

[Walter Roberson]

Reminder you can num2cell and cell2struct to convert an array to struct.

[Biza Ferreira]

Walter Roberson,

Thanks for your answer, my problem is the following... I have develop a code in C to read the ouput of my ECG data aquisition, in my output I built a file with name INPUT.txt, this file is a raw data file, with C code I have convert it into a hexadecimal file,, now I need do the same to ploat it to a graph, this way I decide use the matlab app designer, to make a GUI were the user can read the own signs. Can anyone help me with this and construct the same for matlab code?

Thanks in advance...

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

typedef struct _RTC_C_Calendar
{
    uint32_t seconds;
    uint32_t minutes;
    uint32_t hours;
    uint32_t dayOfWeek;
    uint32_t dayOfmonth;
    uint32_t month;
    uint32_t year;
} RTC_C_Calendar;   // 28 bytes

typedef struct {
  uint32_t id;                    // uint32_t id = 4 bytes
  volatile int32_t sDaqVals[8];   // long = 4 bytes * 8 = 32 bytes
  bool leadoffDetected;           // bool = 1 bytes = alinhamento => 4 bytes
  int32_t sresultTempResp;        // long = 4 bytes
  float vbattery;
  float temperature;
  RTC_C_Calendar datetime;
} ads1292OutputValues;            // 4(id) + 32(sDaq) + 1(bool) + 4(int32) = 41 bytes = alinhamento(bool) => 44 bytes + 28(RTC) + 4(float) + 4(float) = 80 bytes

struct long_byte {
    union {
        uint32_t val;
        uint8_t id[4];
    };
};

int main(void)
{
    FILE *fp;
    int ch;
    int i;
    int j;
    int lineSize = 4;

    struct long_byte id;

    ads1292OutputValues rawData;

    if ((fp = fopen("INPUT.txt", "rb+")) == NULL) {
        printf("O arquivo nao pode ser aberto.\n");
    }
    else {
        i = 0;
        j = 0;

        while (!feof(fp)) {
            fread(&rawData, sizeof(ads1292OutputValues), 1, fp);

            printf("id: %d, val[8]: %08x, %08x, %08x, %08x, %08x, %08x, %08x, %08x, %d, %08x, %.6f[v], %.6fºC, %02d, %02d-%02d-%04d : %02d:%02d:%02d\n",
                rawData.id, 
                rawData.sDaqVals[0], rawData.sDaqVals[1], rawData.sDaqVals[2], rawData.sDaqVals[3], 
                rawData.sDaqVals[4], rawData.sDaqVals[5], rawData.sDaqVals[6], rawData.sDaqVals[7],
                rawData.leadoffDetected, rawData.sresultTempResp,
                rawData.vbattery, rawData.temperature,
                rawData.datetime.dayOfWeek, 
                rawData.datetime.dayOfmonth, rawData.datetime.month, rawData.datetime.year,
                rawData.datetime.hours, rawData.datetime.minutes, rawData.datetime.seconds);
        }
    }

    fclose(fp);

    printf("\n");
    printf("Finished!\n");

    return 0;
}

[Steven Lord]

For operations on your long_byte use typecast, potentially in conjunction with swapbytes.

x = int8([12, 34, 56, 78])

x = 1×4

12 34 56 78

y = typecast(x, 'int32')

y = int32 1312301580

format hex
x

x = 1×4

0c 22 38 4e

y

y = int32
   4e38220c

swapbytes(y)

ans = int32
   0c22384e

[Walter Roberson]

Why convert it to hexadecimal?

Perhaps read the binary using memmapfile()?

[Biza Ferreira]

Hello Walter Roberson,

can you give me some help with this? I dont have a solid knowledge to do this in matlab

[Walter Roberson]

See the example at https://www.mathworks.com/help/matlab/ref/memmapfile.html#bt3tmd4-1 for handling effectively a repeated struct