/* vi: set sw=4 ts=4: */
/*
- * Mini head implementation for busybox
+ * head implementation for busybox
*
- *
- * Copyright (C) 1999 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
*
*/
-#include "internal.h"
-#include <errno.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 */
+
#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <ctype.h>
+#include <unistd.h>
+#include "busybox.h"
-const char head_usage[] =
- "head [OPTION] [FILE]...\n\n"
- "Print 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"
+static const char head_opts[] =
+ "n:"
+#ifdef CONFIG_FEATURE_FANCY_HEAD
+ "c:qv"
+#endif
+ ;
- "Options:\n" "\t-n NUM\t\tPrint first NUM lines instead of first 10\n";
+static const char header_fmt_str[] = "\n==> %s <==\n";
-int head(int len, FILE * src)
+int head_main(int argc, char **argv)
{
- int i;
- char buffer[1024];
+ unsigned long count = 10;
+ unsigned long i;
+#ifdef CONFIG_FEATURE_FANCY_HEAD
+ int count_bytes = 0;
+ int header_threshhold = 1;
+#endif
- for (i = 0; i < len; i++) {
- fgets(buffer, 1024, src);
- if (feof(src)) {
- break;
- }
- fputs(buffer, stdout);
- }
- return 0;
-}
+ FILE *fp;
+ const char *fmt;
+ char *p;
+ int opt;
+ int c;
+ int retval = EXIT_SUCCESS;
-/* BusyBoxed head(1) */
-int head_main(int argc, char **argv)
-{
- char opt;
- int len = 10, tmplen, i;
+ /* 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;
+ }
- /* parse argv[] */
- for (i = 1; i < argc; i++) {
- if (argv[i][0] == '-') {
- opt = argv[i][1];
- switch (opt) {
+ 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:
- fprintf(stderr, "head: 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) {
- fprintf(stderr, "head: %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();
}
- }
- exit(0);
-}
+ fmt = header_fmt_str;
+ } while (*++argv);
-/* $Id: head.c,v 1.8 2000/02/08 19:58:47 erik Exp $ */
+ bb_fflush_stdout_and_exit(retval);
+}