1,s,2,3,4,5
1,r,6,7,8,9
2,s,1,3,4,5
2,r,6,78,8,9

#include <stdio.h>
#define NODE_ROUTING_FILE "node_routing"
#define MAX_PEERS 100

int read_line(FILE* the_file, char* the_buf)
{
   int done = 0;
   char this_char;
   int ret_code = 0;

   while (!done)
   {
      if (!fread(&this_char, 1, 1, the_file))
      {  ret_code = 1;
         done = 1;
      }
      else
      {  if (this_char == '\n')
         {  done = 1;
         }
         else
         {  *the_buf++ = this_char;
   }  }  }
   *the_buf = 0;
   return ret_code;
}

/* return '1' if no comma found
 */

int get_next_string(char* the_line, char* buf)
{
   int done = 0;
   char this_char;
   int ret_code = 0;
   char* ptr = the_line;

   while (!done)
   {  if (*ptr == ',')
      {  *buf = 0;
         done = 1;
      }
      else if (*ptr == 0)
      {  *buf = 0;
         return -1;
      }
      else if (*ptr != ' ')
      {  *buf++ = *ptr;
      }
      ptr++;
   }
   return ptr - the_line;
}

int process_line(char* the_line, int my_id, int* send_to, int* rcv_from)
{
   int done = 0;
   char this_char;
   char this_string[100];
   int this_id;
   int send_mode = 0;
   int offset = 0;
   int stage = 0;
   int peers_stored = 0;

   while (!done)
   {  offset = get_next_string(the_line, this_string);
      if (offset == -1)
      {  done = 1;
      }
      else
      {  the_line += offset;
      }

      if (stage == 0)
      {  stage++;
         this_id = atoi(this_string);
         if (my_id != this_id)
         {  return 0;
      }  }
      else if (stage == 1)
      {  stage++;
         if (this_string[0] == 's' || this_string[0] == 'S')
         {  send_mode = 1;
         }
         else if (this_string[0] == 'r' || this_string[0] == 'R')
         {  send_mode = 0;
         }
         else
         {  printf("??? %s ??? list\n", this_string[0]);
            return 0;
         }
      }
      else
      {  if (send_mode)
         {  *send_to++ = atoi(this_string);
         }
         else
         {  *rcv_from++ = atoi(this_string);
         }
         peers_stored++;
      }
   }
   return peers_stored;
}

/* returns 1 if fails
 */
int process_file(char* file_name, int id, int* send_to, int* rcv_from)
{
   FILE *input_file;
   int i;
   char this_line[400];
   int done = 0;
   int read_status;

   for (i = 0; i < MAX_PEERS; i++)
   {  send_to[i]  = 0;
      rcv_from[i] = 0;
   }

   input_file = fopen(file_name, "r");
   if (input_file == NULL)
   {  printf("Can't open node routing file '%s'\n", NODE_ROUTING_FILE);
      return 1;
   }

   while (!done)
   {  read_status = read_line(input_file, this_line);
      if (read_status)
      {  done = 1;
      }
      else
      {  process_line(this_line, id, send_to, rcv_from);
      }
   }
   return 0;
}

int main(void)
{

   int send_to[MAX_PEERS];
   int rcv_from[MAX_PEERS];
   int i;
   int my_id = 2;
   int result;

   result = process_file(NODE_ROUTING_FILE, my_id, send_to, rcv_from);
   if (result)
   {  printf("File parsing failure\n");
      return 1;
   }

   printf("id %d sends to: ", my_id);
   i = 0;
   while (send_to[i])
   {  printf("%d, ", send_to[i]);
      i++;
   }
   printf("\n");

   printf("id %d receives from: ", my_id);
   i = 0;
   while (rcv_from[i])
   {  printf("%d, ", rcv_from[i]);
      i++;
   }
   printf("\n");
}

-- MattWalsh - 16 Sep 2004