1 files changed, 95 insertions, 59 deletions

diff --git a/coreutils/head.c b/coreutils/head.c
index ad21e1b95..dab4de11b 100644
--- a/coreutils/head.c
+++ b/coreutils/head.c
@@ -1,9 +1,8 @@
 /* vi: set sw=4 ts=4: */
 /*
- * Mini head implementation for busybox
+ * head implementation for busybox
  *
- * Copyright (C) 1999 by Lineo, inc. and John Beppu
- * Copyright (C) 1999,2000,2001 by John Beppu <beppu@codepoet.org>
+ * 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
@@ -21,82 +20,119 @@
  *
  */
 
+/* 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 <getopt.h>
 #include <stdlib.h>
-#include <string.h>
+#include <limits.h>
 #include <ctype.h>
+#include <unistd.h>
 #include "busybox.h"
 
-static int head(int len, FILE *fp)
-{
-        int i;
-        char *input;
+static const char head_opts[] =
+        "n:"
+#ifdef CONFIG_FEATURE_FANCY_HEAD
+        "c:qv"
+#endif
+        ;
 
-        for (i = 0; i < len; i++) {
-                if ((input = get_line_from_file(fp)) == NULL)
-                        break;
-                fputs(input, stdout);
-                free(input);
-        }
-        return 0;
-}
+static const char header_fmt_str[] = "\n==> %s <==\n";
 
-/* BusyBoxed head(1) */
 int head_main(int argc, char **argv)
 {
+        unsigned long count = 10;
+        unsigned long i;
+#ifdef CONFIG_FEATURE_FANCY_HEAD
+        int count_bytes = 0;
+        int header_threshhold = 1;
+#endif
+
         FILE *fp;
-        int need_headers, opt, len = 10, status = EXIT_SUCCESS;
+        const char *fmt;
+        char *p;
+        int opt;
+        int c;
+        int retval = EXIT_SUCCESS;
 
-        if (( argc >= 2 ) && ( argv [1][0] == '-' ) && isdigit ( argv [1][1] )) {
-                len = atoi ( &argv [1][1] );
-                optind = 2;
+        /* 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[] */
-        while ((opt = getopt(argc, argv, "n:")) > 0) {
-                switch (opt) {
-                case 'n':
-                        len = atoi(optarg);
-                        if (len >= 0)
+        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;
-                        /* fallthrough */
-                default:
-                        show_usage();
+                        case 'c':
+                                count_bytes = 1;
+                                /* fall through */
+#endif
+                        case 'n':
+                                p = optarg;
+                        GET_COUNT:
+                                count = bb_xgetularg10(p);
+                                break;
+                        default:
+                                bb_show_usage();
                 }
         }
 
-        /* get rest of argv[] or stdin if nothing's left */
-        if (argv[optind] == NULL) {
-                head(len, stdin);
-                return status;
-        } 
+        argv += optind;
+        if (!*argv) {
+                *--argv = "-";
+        }
 
-        need_headers = optind != (argc - 1);
-        while (argv[optind]) {
-                if (strcmp(argv[optind], "-") == 0) {
-                        fp = stdin;
-                        argv[optind] = "standard input";
-                } else {
-                        if ((fp = wfopen(argv[optind], "r")) == NULL)
-                                status = EXIT_FAILURE;
-                }
-                if (fp) {
-                        if (need_headers) {
-                                printf("==> %s <==\n", argv[optind]);
+        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
+
+        do {
+                if ((fp = bb_wfopen_input(*argv)) != NULL) {
+                        if (fp == stdin) {
+                                *argv = (char *) bb_msg_standard_input;
                         }
-                        head(len, fp);
-                        if (ferror(fp)) {
-                                perror_msg("%s", argv[optind]);
-                                status = EXIT_FAILURE;
+                        if (header_threshhold) {
+                                bb_printf(fmt, *argv);
                         }
-                        if (optind < argc - 1)
-                                putchar('\n');
-                        if (fp != stdin)
-                                fclose(fp);
+                        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();
                 }
-                optind++;
-        }
+                fmt = header_fmt_str;
+        } while (*++argv);
 
-        return status;
+        bb_fflush_stdout_and_exit(retval);
 }