CODEWITHSUNDEEP
cfile-io
sandeep
sandeep

Reputation: 21

Read from a file and store in structure

i want to copy this data @822!172.28.6.137!172.28.6.110!5000!6000| form file input_data to this structure,to copy 822 from the file to input.key and 172.28.6.137 to src_ip when ever ! is encountered it should copy the data from file to next member of the structure how to do this?

struct input_par
{
    char key[5];
    char src_ip[15];
    char dst_ip[15];
    char src_port[5];
    char dst_port[5];
};

main()
{
    int i;
    char ch;
    FILE *fp;
    struct input_par input;
    fp = fopen("input_data","r");
    if(fp == NULL)
    printf("file open failed \n");
    else
    {
        ch = fgetc(fp);
        if(ch=='@')
            printf("data is valid\n");
        fseek(fp,1,1);
        while(ch!='|')
        {
            input.key      =
            input.src_ip   =
            input.dst_ip   =
            input.src_port =
            input.dst_port =
        }       
    }

Upvotes: 1

Views: 3362

Answers (4)

Robert S. Barnes
Robert S. Barnes

Reputation: 40558

You can use fscanf. I would do something like:

struct input_par {
    char key[5];
    char src_ip[15], dst_ip[15];
    int src_port;
    int dst_port;
}

struct input_par ip;

if ( fscanf(fp, "@%s!%s!%s!%d!%d", 
           ip.key, ip.src_ip, ip.dst_ip, ip.src_port, ip.dst_port) != 5 )
      do_error();

Upvotes: 1

August Karlstrom
August Karlstrom

Reputation: 11377

A call to fscanf will do the job:

fscanf(fp, "@%[0-9]!%[0-9.]!%[0-9.]!%[0-9]!%[0-9]|", input.key, input.src_ip, input.dst_ip, input.src_port, input.dst_port);

Note that you first have to make sure that the input strings do not overflow your array fields.

Upvotes: 0

Habalusa
Habalusa

Reputation: 1800

First, let's have a function which reads one field(though it won't detect partially read fields)

int read_field(FILE *f,char *destination,size_t max_len)
{
   int c;
   size_t count = 0;
   while(c = fgetc(f)) != EOF) {
     if(c == '!' || c == '|')
        break;
     if(count < max_len - 1)
         destination[count++] = c;
    }

   destination[count] = 0;
   return count;
}

Then read the fields:

  int ch = fgetc(fp);
  if(ch=='@') {
     int ok;
     printf("data is valid\n");
     ok = get_field(fp,input.key,sizeof input.key);
     ok && get_field(fp,input.src_ip,sizeof input.src_ip);
     ok && get_field(fp,input.dst_ip,sizeof input.dst_ip);
     ok && get_field(fp,input.src_port,sizeof input.src_port);
     ok && get_field(fp,input.dst_port,sizeof input.dst_port);
     if(!ok) {
        puts("parse error");
     }
  }

Upvotes: 0

djfoxmccloud
djfoxmccloud

Reputation: 599

You can use regular expressions see regexp.h from libstd

If you just have to use this kind of thing here, you can juste go through your char[] and count the ! and depending and how much you have previously seen you add the chars you've read in the correct section.

(also fscanf is easier)

Upvotes: 1

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