source: MondoRescue/branches/3.0/mindi-busybox/coreutils/tac.c@ 3085

/* vi: set sw=4 ts=4: */
/*
 * tac implementation for busybox
 *
 * Copyright (C) 2003  Yang Xiaopeng  <yxp at hanwang.com.cn>
 * Copyright (C) 2007  Natanael Copa  <natanael.copa@gmail.com>
 * Copyright (C) 2007  Tito Ragusa    <farmatito@tiscali.it>
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 *
 */

/* tac - concatenate and print files in reverse */

/* Based on Yang Xiaopeng's (yxp at hanwang.com.cn) patch
 * http://www.uclibc.org/lists/busybox/2003-July/008813.html
 */

#include "libbb.h"

/* This is a NOEXEC applet. Be very careful! */

struct lstring {
    int size;
    char buf[1];
};

int tac_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tac_main(int argc UNUSED_PARAM, char **argv)
{
    char **name;
    FILE *f;
    struct lstring *line = NULL;
    llist_t *list = NULL;
    int retval = EXIT_SUCCESS;

#if ENABLE_DESKTOP
/* tac from coreutils 6.9 supports:
       -b, --before
              attach the separator before instead of after
       -r, --regex
              interpret the separator as a regular expression
       -s, --separator=STRING
              use STRING as the separator instead of newline
We support none, but at least we will complain or handle "--":
*/
    getopt32(argv, "");
    argv += optind;
#else
    argv++;
#endif
    if (!*argv)
        *--argv = (char *)"-";
    /* We will read from last file to first */
    name = argv;
    while (*name)
        name++;

    do {
        int ch, i;

        name--;
        f = fopen_or_warn_stdin(*name);
        if (f == NULL) {
            /* error message is printed by fopen_or_warn_stdin */
            retval = EXIT_FAILURE;
            continue;
        }

        errno = i = 0;
        do {
            ch = fgetc(f);
            if (ch != EOF) {
                if (!(i & 0x7f))
                    /* Grow on every 128th char */
                    line = xrealloc(line, i + 0x7f + sizeof(int) + 1);
                line->buf[i++] = ch;
            }
            if (ch == '\n' || (ch == EOF && i != 0)) {
                line = xrealloc(line, i + sizeof(int));
                line->size = i;
                llist_add_to(&list, line);
                line = NULL;
                i = 0;
            }
        } while (ch != EOF);
        /* fgetc sets errno to ENOENT on EOF, we don't want
         * to warn on this non-error! */
        if (errno && errno != ENOENT) {
            bb_simple_perror_msg(*name);
            retval = EXIT_FAILURE;
        }
    } while (name != argv);

    while (list) {
        line = (struct lstring *)list->data;
        xwrite(STDOUT_FILENO, line->buf, line->size);
        if (ENABLE_FEATURE_CLEAN_UP) {
            free(llist_pop(&list));
        } else {
            list = list->link;
        }
    }

    return retval;
}