add "make help"

[oweals/busybox.git] / coreutils / head.c

diff --git a/coreutils/head.c b/coreutils/head.c
index b82678dc23da622baf00ec5d17c86cc0964b9c91..dab4de11b16555514da7eff3bcc194bb86fd29d5 100644 (file)
--- a/coreutils/head.c
+++ b/coreutils/head.c
@@ -1,10 +1,8 @@
 /* vi: set sw=4 ts=4: */
 /*
- * Mini head implementation for busybox
+ * head implementation for busybox
  *
- *
- * Copyright (C) 1999,2000 by Lineo, inc.
- * Written by John Beppu <beppu@lineo.com>
+ * Copyright (C) 2003  Manuel Novoa III  <mjn3@codepoet.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -22,93 +20,119 @@
  *
  */
 
-#include "internal.h"
-#include <errno.h>
-#include <stdio.h>
+/* BB_AUDIT SUSv3 compliant */
+/* BB_AUDIT GNU compatible -c, -q, and -v options in 'fancy' configuration. */
+/* http://www.opengroup.org/onlinepubs/007904975/utilities/head.html */
 
-const char head_usage[] =
-       "head [OPTION] [FILE]...\n"
-#ifndef BB_FEATURE_TRIVIAL_HELP
-       "\nPrint first 10 lines of each FILE to standard output.\n"
-       "With more than one FILE, precede each with a header giving the\n"
-       "file name. With no FILE, or when FILE is -, read standard input.\n\n"
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <ctype.h>
+#include <unistd.h>
+#include "busybox.h"
 
-       "Options:\n" "\t-n NUM\t\tPrint first NUM lines instead of first 10\n"
+static const char head_opts[] =
+       "n:"
+#ifdef CONFIG_FEATURE_FANCY_HEAD
+       "c:qv"
 #endif
        ;
 
-int head(int len, FILE * src)
-{
-       int i;
-       char buffer[1024];
-
-       for (i = 0; i < len; i++) {
-               fgets(buffer, 1024, src);
-               if (feof(src)) {
-                       break;
-               }
-               fputs(buffer, stdout);
-       }
-       return 0;
-}
+static const char header_fmt_str[] = "\n==> %s <==\n";
 
-/* BusyBoxed head(1) */
 int head_main(int argc, char **argv)
 {
-       char opt;
-       int len = 10, tmplen, i;
+       unsigned long count = 10;
+       unsigned long i;
+#ifdef CONFIG_FEATURE_FANCY_HEAD
+       int count_bytes = 0;
+       int header_threshhold = 1;
+#endif
 
-       /* parse argv[] */
-       for (i = 1; i < argc; i++) {
-               if (argv[i][0] == '-') {
-                       opt = argv[i][1];
-                       switch (opt) {
+       FILE *fp;
+       const char *fmt;
+       char *p;
+       int opt;
+       int c;
+       int retval = EXIT_SUCCESS;
+
+       /* Allow legacy syntax of an initial numeric option without -n. */
+       if ((argc > 1) && (argv[1][0] == '-')
+               /* && (isdigit)(argv[1][1]) */
+               && (((unsigned int)(argv[1][1] - '0')) <= 9)
+       ) {
+               --argc;
+               ++argv;
+               p = (*argv) + 1;
+               goto GET_COUNT;
+       }
+
+       while ((opt = getopt(argc, argv, head_opts)) > 0) {
+               switch(opt) {
+#ifdef CONFIG_FEATURE_FANCY_HEAD
+                       case 'q':
+                               header_threshhold = INT_MAX;
+                               break;
+                       case 'v':
+                               header_threshhold = -1;
+                               break;
+                       case 'c':
+                               count_bytes = 1;
+                               /* fall through */
+#endif
                        case 'n':
-                               tmplen = 0;
-                               if (++i < argc)
-                                       tmplen = atoi(argv[i]);
-                               if (tmplen < 1)
-                                       usage(head_usage);
-                               len = tmplen;
+                               p = optarg;
+                       GET_COUNT:
+                               count = bb_xgetularg10(p);
                                break;
-                       case '-':
-                       case 'h':
-                               usage(head_usage);
                        default:
-                               errorMsg("invalid option -- %c\n", opt);
-                               usage(head_usage);
-                       }
-               } else {
-                       break;
+                               bb_show_usage();
                }
        }
 
-       /* get rest of argv[] or stdin if nothing's left */
-       if (i >= argc) {
-               head(len, stdin);
-
-       } else {
-               int need_headers = ((argc - i) > 1);
+       argv += optind;
+       if (!*argv) {
+               *--argv = "-";
+       }
 
-               for (; i < argc; i++) {
-                       FILE *src;
+       fmt = header_fmt_str + 1;
+#ifdef CONFIG_FEATURE_FANCY_HEAD
+       if (argc - optind <= header_threshhold) {
+               header_threshhold = 0;
+       }
+#else
+       if (argc <= optind + 1) {
+               fmt += 11;
+       }
+       /* Now define some things here to avoid #ifdefs in the code below.
+        * These should optimize out of the if conditions below. */
+#define header_threshhold   1
+#define count_bytes         0
+#endif
 
-                       src = fopen(argv[i], "r");
-                       if (!src) {
-                               errorMsg("%s: %s\n", argv[i], strerror(errno));
-                       } else {
-                               /* emulating GNU behaviour */
-                               if (need_headers) {
-                                       fprintf(stdout, "==> %s <==\n", argv[i]);
-                               }
-                               head(len, src);
-                               if (i < argc - 1) {
-                                       fprintf(stdout, "\n");
+       do {
+               if ((fp = bb_wfopen_input(*argv)) != NULL) {
+                       if (fp == stdin) {
+                               *argv = (char *) bb_msg_standard_input;
+                       }
+                       if (header_threshhold) {
+                               bb_printf(fmt, *argv);
+                       }
+                       i = count;
+                       while (i && ((c = getc(fp)) != EOF)) {
+                               if (count_bytes || (c == '\n')) {
+                                       --i;
                                }
+                               putchar(c);
+                       }
+                       if (bb_fclose_nonstdin(fp)) {
+                               bb_perror_msg("%s", *argv);     /* Avoid multibyte problems. */
+                               retval = EXIT_FAILURE;
                        }
+                       bb_xferror_stdout();
                }
-       }
-       return(0);
-}
+               fmt = header_fmt_str;
+       } while (*++argv);
 
-/* $Id: head.c,v 1.12 2000/07/14 01:51:25 kraai Exp $ */
+       bb_fflush_stdout_and_exit(retval);
+}