Fragmentation (Part-1) header file.txt

void SendPdu (struct Pdu pdu, char* destinationFolder, char* originalFileExtn)
{
    int totalSize = 18 + strlen(pdu.data) + 4;
    char fragmentData[totalSize];

    sprintf(fragmentData, "%08X%04X%02X%04X%s%04X", 
        pdu.header.messageIdentifier,  pdu.header.sequenceNumber, pdu.header.isLastFlag, pdu.header.length, pdu.data, pdu.checksum);

    char fileName[400];

    int fileFilePathLength = strlen(destinationFolder) + 1 + 19 + strlen(originalFileExtn) + 3;

    snprintf(fileName, fileFilePathLength, "%s\\FRAG_%08X_%04X.%sfrg", destinationFolder, pdu.header.messageIdentifier, pdu.header.sequenceNumber, originalFileExtn);

    FILE *fragmentFile; 
    fragmentFile = fopen (fileName, "w"); 
    if (fragmentFile == NULL) 
    { 
        fprintf(stderr, "\nError opend file\n"); 
        exit (1); 
    } 
      
    fwrite (fragmentData, strlen(fragmentData), 1, fragmentFile); 
    if(fwrite != 0)  
    {
        printf("\nFragment(%d): File %s written successfully !", pdu.header.sequenceNumber, fileName); 
    }
    else
    { 
        printf("Error in writting Fragment File %s !\n", fileName); 
    }
    fclose (fragmentFile); 
}

void ExecuteFragmentation()
{
    printf("\nEnter the file path: ");
    char filepath[256];
    gets(filepath);

    FILE *file;
    file = fopen(filepath, "rb"); //read binary
    
    if(file == NULL)
    {
        printf("The path (%s) does not look valid !\n", filepath);
        exit(1);
    }

    printf("Enter the destination folder: ");
    char destinationFolder[400];
    gets(destinationFolder);

    printf("Enter the fragment size: ");
    int fragmentSize;
    scanf("%d",&fragmentSize);
    
    char extn[10] = "";
    GetFileExtension(filepath, extn);

    fseek(file, 0L, SEEK_END); 
    long int fileSize;
    fileSize = ftell(file);
    
    printf("\n\nThe File Size is: %d bytes", fileSize);
    printf("\nThe Fragment Size is: %d bytes", fragmentSize);

    int fragments = fileSize / fragmentSize;
    if(fileSize % fragmentSize != 0)
    {
        fragments += 1;
    }
    printf("\nTotal expected fargments are: %d\n\n", fragments);

    long messageIdentifier = GenerateGUID();
    fseek(file, 0, SEEK_SET);

    int sequenceNumber = 0;
    int bytesRead = 0;
    
    for(int i = 0; i < fragments; i++)
    {
        char buffer[fragmentSize + 1];
        bytesRead = fread(&buffer, 1, fragmentSize, file);
        buffer[fragmentSize] = '\0';

        char unsigned isLastFlag = 0;
        if(i == fragments - 1)
        {
            isLastFlag = 1;
        }

        char encodedData[((strlen(buffer)/3) *4)+2];
        EncodeBase64(buffer, encodedData); 

        struct PduHeader header = BuildPduHeader(messageIdentifier, ++sequenceNumber, strlen(encodedData), isLastFlag);
        short checksum = ComputeChecksum(encodedData);
        struct Pdu pdu = BuildPdu(header, encodedData, checksum);
        SendPdu(pdu, destinationFolder, extn);
    } 

    fclose(file);
}