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Extract Packet Fields from Byte Stream

Code

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

typedef struct {
    uint8_t start;
    uint8_t command;
    uint16_t data;
    uint8_t crc;
    uint8_t end;
} Packet;

void print_packet_fields(uint8_t *buffer) {
    // Overlay struct and print values
    Packet packet;

    packet.start = buffer[0];
    packet.command = buffer[1];
    packet.data = buffer[2];
    packet.data += buffer[3] << 8;
    packet.crc = buffer[4];
    packet.end = buffer[5];

    printf("Start: %d\n", packet.start);
    printf("Command: %d\n", packet.command);
    printf("Data: %d\n", packet.data);
    printf("CRC: %d\n", packet.crc);
    printf("End: %d\n", packet.end);
}

int main() {
    uint8_t buffer[6];
    for (int i = 0; i < 6; i++) {
        scanf("%hhu", &buffer[i]);
    }
    print_packet_fields(buffer);
    return 0;
}

Solving Approach

/*
buffer as an input
populate the packet structure with the items of buffer

How is the data updated ?
buffer[0] = packet.start;
buffer[1] = packet.command;
buffer[2] = packet.data;
buffer[3] << 8 = packet.start;
buffer[4] = packet.crc;
buffer[5] = packet.end;

packet.data = buffer[2];
packet.data += buffer[3] << 8 // add sequentially


*/

 

 

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Input

165 1 52 18 119 90

Expected Output

Start: 165 Command: 1 Data: 4660 CRC: 119 End: 90