source: src/router/busybox/coreutils/expand.c @ 8864

/* expand - convert tabs to spaces
 * unexpand - convert spaces to tabs
 *
 * Copyright (C) 89, 91, 1995-2006 Free Software Foundation, Inc.
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 *
 * David MacKenzie <djm@gnu.ai.mit.edu>
 *
 * Options for expand:
 * -t num  --tabs=NUM      Convert tabs to num spaces (default 8 spaces).
 * -i      --initial       Only convert initial tabs on each line to spaces.
 *
 * Options for unexpand:
 * -a      --all           Convert all blanks, instead of just initial blanks.
 * -f      --first-only    Convert only leading sequences of blanks (default).
 * -t num  --tabs=NUM      Have tabs num characters apart instead of 8.
 *
 *  Busybox version (C) 2007 by Tito Ragusa <farmatito@tiscali.it>
 *
 *  Caveat: this versions of expand and unexpand don't accept tab lists.
 */

#include "libbb.h"

enum {
        OPT_INITIAL     = 1 << 0,
        OPT_TABS        = 1 << 1,
        OPT_ALL         = 1 << 2,
};

static void xputchar(char c)
{
        if (putchar(c) < 0)
                bb_error_msg_and_die(bb_msg_write_error);
}

#if ENABLE_EXPAND
static void expand(FILE *file, unsigned tab_size, unsigned opt)
{
        char *line;
        char *ptr;
        int convert;
        int pos;

        /* Increment tab_size by 1 locally.*/
        tab_size++;

        while ((line = xmalloc_fgets(file)) != NULL) {
                convert = 1;
                pos = 0;
                ptr = line;
                while (*line) {
                        pos++;
                        if (*line == '\t' && convert) {
                                for (; pos < tab_size; pos++) {
                                        xputchar(' ');
                                }
                        } else {
                                if ((opt & OPT_INITIAL) && !isblank(*line)) {
                                        convert = 0;
                                }
                                xputchar(*line);
                        }
                        if (pos == tab_size) {
                                pos = 0;
                        }
                        line++;
                }
                free(ptr);
        }
}
#endif

#if ENABLE_UNEXPAND
static void unexpand(FILE *file, unsigned int tab_size, unsigned opt)
{
        char *line;
        char *ptr;
        int convert;
        int pos;
        int i = 0;
        int column = 0;

        while ((line = xmalloc_fgets(file)) != NULL) {
                convert = 1;
                pos = 0;
                ptr = line;
                while (*line) {
                        while ((*line == ' ' || *line == '\t') && convert) {
                                pos += (*line == ' ') ? 1 : tab_size;
                                line++;
                                column++;
                                if ((opt & OPT_ALL) && column == tab_size) {
                                        column = 0;
                                        goto put_tab;
                                }
                        }
                        if (pos) {
                                i = pos / tab_size;
                                if (i) {
                                        for (; i > 0; i--) {
 put_tab:
                                                xputchar('\t');
                                        }
                                } else {
                                        for (i = pos % tab_size; i > 0; i--) {
                                                xputchar(' ');
                                        }
                                }
                                pos = 0;
                        } else {
                                if (opt & OPT_INITIAL) {
                                        convert = 0;
                                }
                                if (opt & OPT_ALL) {
                                        column++;
                                }
                                xputchar(*line);
                                line++;
                        }
                }
                free(ptr);
        }
}
#endif

int expand_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int expand_main(int argc, char **argv)
{
        /* Default 8 spaces for 1 tab */
        const char *opt_t = "8";
        FILE *file;
        unsigned tab_size;
        unsigned opt;
        int exit_status = EXIT_SUCCESS;

#if ENABLE_FEATURE_EXPAND_LONG_OPTIONS
        static const char expand_longopts[] ALIGN1 =
                /* name, has_arg, val */
                "initial\0"          No_argument       "i"
                "tabs\0"             Required_argument "t"
        ;
#endif
#if ENABLE_FEATURE_UNEXPAND_LONG_OPTIONS
        static const char unexpand_longopts[] ALIGN1 =
                /* name, has_arg, val */
                "first-only\0"       No_argument       "i"
                "tabs\0"             Required_argument "t"
                "all\0"              No_argument       "a"
        ;
#endif

        if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e')) {
                USE_FEATURE_EXPAND_LONG_OPTIONS(applet_long_options = expand_longopts);
                opt = getopt32(argv, "it:", &opt_t);
        } else if (ENABLE_UNEXPAND) {
                USE_FEATURE_UNEXPAND_LONG_OPTIONS(applet_long_options = unexpand_longopts);
                /* -t NUM sets also -a */
                opt_complementary = "ta";
                opt = getopt32(argv, "ft:a", &opt_t);
                /* -f --first-only is the default */
                if (!(opt & OPT_ALL)) opt |= OPT_INITIAL;
        }
        tab_size = xatou_range(opt_t, 1, UINT_MAX);

        argv += optind;

        /* If no args are given, read from stdin */
        if (!*argv) {
                *--argv = (char*)bb_msg_standard_input;
                goto use_stdin;
        }

        do {
                if (NOT_LONE_CHAR(*argv, '-')) {
                        file = fopen_or_warn(*argv, "r");
                        if (!file) {
                                exit_status = EXIT_FAILURE;
                                continue;
                        }
                } else {
 use_stdin:
                        file = stdin;
                }

                if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e'))
                        USE_EXPAND(expand(file, tab_size, opt));
                else if (ENABLE_UNEXPAND)
                        USE_UNEXPAND(unexpand(file, tab_size, opt));

                /* Check and close the file */
                /* We do want all of them to execute, thus | instead of || */
                if (ferror(file) | fclose_if_not_stdin(file)) {
                        bb_simple_perror_msg(*argv);
                        exit_status = EXIT_FAILURE;
                }
                /* If stdin also clear EOF */
                if (file == stdin)
                        clearerr(file);
        } while (*++argv);

        /* Now close stdin also */
        /* (if we didn't read from it, it's a no-op) */
        if (fclose(stdin))
                bb_perror_msg_and_die(bb_msg_standard_input);

        fflush_stdout_and_exit(exit_status);
}