source: kBuild/vendor/sed/4.1.5/testsuite/tst-regex2.c@ 599

#include <errno.h>
#include <fcntl.h>
#include <regex.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <unistd.h>

int
main (int argc, char *argv[])
{
  struct stat st;
  static const char *pat[] = {
    ".?.?.?.?.?.?.?argc",
    "(.?)(.?)(.?)(.?)(.?)(.?)(.?)argc",
    "((((((((((.?))))))))))((((((((((.?))))))))))((((((((((.?))))))))))"
    "((((((((((.?))))))))))((((((((((.?))))))))))((((((((((.?))))))))))"
    "((((((((((.?))))))))))argc" };

  size_t len;
  int fd;
  int testno, i, j, k, l;
  char *string;
  char *buf;

  if (argc < 2)
    abort ();

  fd = open (argv[1], O_RDONLY);
  if (fd < 0)
    {
      printf ("Couldn't open %s: %s\n", argv[1], strerror (errno));
      abort ();
    }

  if (fstat (fd, &st) < 0)
    {
      printf ("Couldn't fstat %s: %s\n", argv[1], strerror (errno));
      abort ();
    }

  buf = malloc (st.st_size + 1);
  if (buf == NULL)
    {
      printf ("Couldn't allocate buffer: %s\n", strerror (errno));
      abort ();
    }

  if (read (fd, buf, st.st_size) != (ssize_t) st.st_size)
    {
      printf ("Couldn't read %s", argv[1]);
      abort ();
    }

  close (fd);
  buf[st.st_size] = '\0';

  string = buf;
  len = st.st_size;

  for (testno = 0; testno < 4; ++testno)
    for (i = 0; i < sizeof (pat) / sizeof (pat[0]); ++i)
      {
        regex_t rbuf;
        struct re_pattern_buffer rpbuf;
        int err;

        printf ("test %d pattern %d", testno, i);
        if (testno < 2)
          {
            err = regcomp (&rbuf, pat[i],
                           REG_EXTENDED | (testno ? REG_NOSUB : 0));
            if (err != 0)
              {
                char errstr[300];
                putchar ('\n');
                regerror (err, &rbuf, errstr, sizeof (errstr));
                puts (errstr);
                return err;
              }
          }
        else
          {
            const char *s;
            re_set_syntax (RE_SYNTAX_POSIX_EGREP
                           | (testno == 3 ? RE_NO_SUB : 0));

            memset (&rpbuf, 0, sizeof (rpbuf));
            s = re_compile_pattern (pat[i], strlen (pat[i]), &rpbuf);
            if (s != NULL)
              {
                printf ("\n%s\n", s);
                abort ();
              }

            /* Just so that this can be tested with earlier glibc as well.  */
            if (testno == 3)
              rpbuf.no_sub = 1;
          }

      if (testno < 2)
        {
          regmatch_t pmatch[71];
          err = regexec (&rbuf, string, 71, pmatch, 0);
          if (err == REG_NOMATCH)
            {
              puts ("\nregexec failed");
              abort ();
            }

          if (testno == 0)
            {
              if (pmatch[0].rm_eo != pmatch[0].rm_so + 11
                  || pmatch[0].rm_eo > len
                  || string + pmatch[0].rm_so >= strchr (string, 'R')
                  || strncmp (string + pmatch[0].rm_so,
                              "n (int argc",
                              sizeof "n (int argc" - 1)
                     != 0)
                {
                  puts ("\nregexec without REG_NOSUB did not find the correct match");
                  abort ();
                }

              if (i > 0)
                for (j = 0, l = 1; j < 7; ++j)
                  for (k = 0; k < (i == 1 ? 1 : 10); ++k, ++l)
                    if (pmatch[l].rm_so != pmatch[0].rm_so + j
                        || pmatch[l].rm_eo != pmatch[l].rm_so + 1)
                      {
                        printf ("\npmatch[%d] incorrect\n", l);
                        abort ();
                      }
            }
        }
      else
        {
          struct re_registers regs;
          int match;

          memset (&regs, 0, sizeof (regs));
          match = re_search (&rpbuf, string, len, 0, len,
                                 &regs);
          if (match < 0)
            {
              puts ("\nre_search failed");
              abort ();
            }

          if (match + 11 > len
              || string + match >= strchr (string, 'R')
              || strncmp (string + match,
                          "n (int argc",
                          sizeof "n (int argc" - 1)
                  != 0)
            {
              puts ("\nre_search did not find the correct match");
              abort ();
            }

          if (testno == 2)
            {
              if (regs.num_regs != 2 + (i == 0 ? 0 : i == 1 ? 7 : 70))
                {
                  printf ("\nincorrect num_regs %d\n", regs.num_regs);
                  abort ();
                }

              if (regs.start[0] != match || regs.end[0] != match + 11)
                {
                  printf ("\nincorrect regs.{start,end}[0] = { %d, %d}\n",
                          regs.start[0], regs.end[0]);
                  abort ();
                }

              if (regs.start[regs.num_regs - 1] != -1
                  || regs.end[regs.num_regs - 1] != -1)
                {
                  puts ("\nincorrect regs.{start,end}[num_regs - 1]");
                  abort ();
                }

              if (i > 0)
                for (j = 0, l = 1; j < 7; ++j)
                  for (k = 0; k < (i == 1 ? 1 : 10); ++k, ++l)
                    if (regs.start[l] != match + j
                        || regs.end[l] != regs.start[l] + 1)
                      {
                        printf ("\nregs.{start,end}[%d] incorrect\n", l);
                        abort ();
                      }
            }
        }

      putchar ('\n');

      if (testno < 2)
        regfree (&rbuf);
      else
        regfree (&rpbuf);
    }

  exit (0);
}