New line(\n) gets added when printing with Hex byte in loop

srinietrx · 01-12-2018, 06:29 AM

I am using slog logger for C to log into file.
In C standard syntax printf when I use to print in hex it print output in single line.

Code:

for(loop = 0; loop < strLen; loop++)
{
     printf("%02X ", fstrParam[loop]);     
}

PHP Code:



Example is shown below. 
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I want to write into file. So I am using slog.slog is logger I got from internet as project to print everything in file.

It works like printf statement for everything. But when I print as below format. It is printing each hex value in single line.

Code:

for(loop = 0; loop < strLen; loop++)
{
     slog_debug(0, "%02X ", fstrParam[loop]);
}

PHP Code:

How can avoid this from my application side? Or I need to modify in slog.

NevemTeve · 01-12-2018, 07:55 AM

You might want to give an URL to this 'slog'-thing.

MadeInGermany · 01-12-2018, 08:37 AM

Without knowing the slog functions - you can sprintf() and strcat() to a string variable, and slog_debug() it at the end.

srinietrx · 01-12-2018, 09:04 AM

@MadeInGermany
Your solution may solve my problem I think.I will implement and confirm.

@NevemTeve
https://github.com/kala13x/slog

NevemTeve · 01-12-2018, 09:20 AM

Well, it doesn't offer such functionality, so you have to build complete lines in your own buffers.

srinietrx · 01-15-2018, 06:25 AM

Hi,
I implemented code as shown below.It is working fine independently.But when I added this to my Project(application) it gets killed after sometime.For your information my application uses thread.
So, My question is whether Hex_Print_In_Single_Line() is correct

Code:

void Hex_Print_In_Single_Line(unsigned char digest[], unsigned char *hex_output);

int main()
{
        slog_init("log_TestProgram", "slog.cfg", 1, 3, 1);//1->File name where log is saved, 2->config file, 3-> Max log level, 4-> Max log file level, 5-> Thread safety flag
        unsigned char output[1024] = {0};
        unsigned char input[1024] = {0};
        strcpy(input, "hello");
        Hex_Print_In_Single_Line(input, output);
        slog_debug(0, "%s\n", output);


}


void Hex_Print_In_Single_Line(unsigned char digest[], unsigned char *hex_output)
{
        char hex_tmp[33]={0};
        int i;
        for (i = 0; i < strlen(digest); i++)
        {
                printf("%02x ", digest[i]);
                sprintf(&hex_tmp[i*2],"%02x", digest[i]);
                strcat(hex_output, &hex_tmp[i*2]);
                strcat(hex_output, " ");
        }
        printf("\n");
}

NevemTeve · 01-15-2018, 06:39 AM

You don't seem to check the maximum lengths.

rtmistler · 01-15-2018, 06:43 AM

My recommendation is that you write your own functions or macros to filter and generate your debug.

Some utility written by someone else suits their needs. If you have their source, you can copy it and edit it to suit what you want it to do.

I typically find that others have refined in ways or to limits that go astray from how I'd do it and instead I'll start with what they have published and morph that into my own rendition, or for something like this, I'll just invent it and incrementally add to it as I need more functionality. And then typically copy it forever into my many projects, providing I liked what I did that first time.

srinietrx · 01-15-2018, 07:06 AM

rtmistler:- In future I will start to read other person's code ,understand and customise according to my need.

NevemTeve:- Yes you are correct. It is because of length. When application got killed I received length more that declared.

Initially I kept it as

PHP Code:



char hex_tmp[1024] = {0};

When I changed to

PHP Code:



char hex_tmp[4096] = {0};

I will add max length check in my code. In general where length check is written. It should be written inside function(i.e.Hex_Print_In_Single_Line()) or Outside in main application.

Thanks.