main.c

gistfile1.c

#include <stdio.h>
#include <string.h>
#include <dirent.h>
#include <stdbool.h>
#include <stdlib.h>
#include <errno.h>

/* email parsing from
 * http://bytes.com/topic/c/answers/215251-regular-expressions-c
 */
void print_email(char str[])
{
  char name[51];
  char email[51];

  int rc = sscanf(str, "%50[^<]<%50[^>]", name, email);

  if (rc == 2)
  {
    printf("%s\t%s\n", email, name);
  }
}
 
/* find the From: line in a file */
void find_from(char *fn)
{
  FILE *file;
  char line[1000];
  bool found = false;

  /* a hack for now */
  int i     = 1;
  int limit = 100;

  if (file = fopen(fn, "r"))
  {
    //while (!found && line != NULL) // no dice?
    while (!found && i <= limit)
    {
      i++;

      // todo: if it's never found, this never ends...
      fgets(line, 1000, file);
      if (strncmp("From: ", line, 6) == 0)
      {
        /* trim leading "From: " and trailing "\n" */
        print_email(strndup(line + 6, strlen(line)-1));
        found = true;
      }
    }

    fclose(file);
  }
  else
  {
    printf("%s: failed to open file.\n", fn);
  }
}
 
/* directory code from
 * http://www.metalshell.com/source_code/116/Read_Directory.html
 */
int main(int argc, char *argv[])
{
  DIR           *dip;
  struct dirent *dit;

  char          *fullpath;
  char          *filename;

  if (argc < 2)
  {
    printf("usage: %s <directory>\n", argv[0]);
    return 1;
  }

  if ((dip = opendir(argv[1])) == NULL)
  {
    perror("opendir");
    return 1;
  }

  /* main loop */
  while ((dit = readdir(dip)) != NULL)
  {
    fullpath = strdup(argv[1]);
    filename = dit->d_name;

    /* skip . and .. */
    if (strcmp(filename, ".") != 0 && strcmp(filename, "..") != 0)
    {
      asprintf(&fullpath, "%s/%s", argv[1], filename);
      find_from(fullpath);
      free(fullpath);
    }
  }

  if (closedir(dip) == -1)
  {
    perror("closedir");
    return 1;
  }
}