/*
 * Copyright (c) 1980, 1987, 1992, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char copyright [] =
"@(#) Copyright (c) 1980, 1987, 1992, 1993\n\
	The Regents of the University of California.  All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char rcsid [] = "$Id: striphead.c,v 1.2 1997/08/30 08:10:50 grog Exp $";
#endif /* not lint */

#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <ctype.h>
#include <unistd.h>
#include <sys/types.h>

/*
 * head - give the first few lines of a stream or of each of a set of files
 *
 * Bill Joy UCB August 24, 1977
 */

void err __P ((int, const char *,...));
void head __P ((FILE *, int));
void obsolete __P ((char *[]));
void usage __P ((void));
void findstring (FILE *fp);

int eval;
char *searchstring = NULL;				    /* string to search for */
#define MAXBUF 4096
char buf [MAXBUF];

int
main (argc, argv)
     int argc;
     char *argv [];
{
  register int ch;
  FILE *fp;
  int first, linecnt;
  char *ep;

  obsolete (argv);
  linecnt = 10;
  while ((ch = getopt (argc, argv, "n:t:")) != EOF)
    switch (ch)
      {
    case 'n':
      linecnt = strtol (optarg, &ep, 10);
      if (*ep || linecnt <= 0)
	err (1, "illegal line count -- %s", optarg);
      break;
    case 't':
      searchstring = optarg;
      break;
    case '?':
    default:
      usage ();
      }
  argc -= optind;
  argv += optind;

  if (*argv)
    for (first = 1; *argv; ++argv)
      {
      if ((fp = fopen (*argv, "r")) == NULL)
	{
	err (0, "%s: %s", *argv, strerror (errno));
	continue;
	}
      if (argc > 1)
	{
	(void) printf ("%s==> %s <==\n",
		       first ? "" : "\n", *argv);
	first = 0;
	}
      head (fp, linecnt);
      (void) fclose (fp);
      }
  else
    head (stdin, linecnt);
  exit (eval);
}

void
head (fp, cnt)
     FILE *fp;
     register int cnt;
{
  register int ch;
  int searchlen = strlen (searchstring);

  if (searchlen)
    {
    while (fgets (buf, MAXBUF, fp)
	   && memcmp (buf, searchstring, searchlen) );  
    while (fgets (buf, MAXBUF, fp))
      {
      if (buf [strlen (buf) - 1] == '\n')
	buf [strlen (buf) - 1] = '\0';
      puts (buf);
      }
    }
  else
    {
    while ((ch = getc (fp)) != EOF && cnt)
      {
      if (putchar (ch) == EOF)
	err (1, "stdout: %s", strerror (errno));
      if (ch == '\n')
	cnt--;
      }
    }
}

void
obsolete (argv)
     char *argv [];
{
  char *ap;

  while (ap = *++argv)
    {
    /* Return if "--" or not "-[0-9]*". */
    if (ap [0] != '-' || ap [1] == '-' || !isdigit (ap [1]))
      return;
    if ((ap = malloc (strlen (*argv) + 2)) == NULL)
      err (1, "%s", strerror (errno));
    ap [0] = '-';
    ap [1] = 'n';
    (void) strcpy (ap + 2, *argv + 1);
    *argv = ap;
    }
}

void
usage ()
{
  (void) fprintf (stderr, "usage: head [-n lines] [file ...]\n");
  exit (1);
}

#if __STDC__
#include <stdarg.h>
#else
#include <varargs.h>
#endif

void
#if __STDC__
err (int fatal, const char *fmt,...)
#else
err (fatal, fmt, va_alist)
     int fatal;
     char *fmt;
     va_dcl
#endif
{
  va_list ap;
#if __STDC__
  va_start (ap, fmt);
#else
  va_start (ap);
#endif
  (void) fprintf (stderr, "head: ");
  (void) vfprintf (stderr, fmt, ap);
  va_end (ap);
  (void) fprintf (stderr, "\n");
  if (fatal)
    exit (1);
  eval = 1;
}