source: MondoRescue/branches/3.3/mindi-busybox/coreutils/expand.c@ 3621

/* 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 source tree.
 *
 * 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.
 */

//usage:#define expand_trivial_usage
//usage:       "[-i] [-t N] [FILE]..."
//usage:#define expand_full_usage "\n\n"
//usage:       "Convert tabs to spaces, writing to stdout\n"
//usage:    IF_FEATURE_EXPAND_LONG_OPTIONS(
//usage:     "\n    -i,--initial    Don't convert tabs after non blanks"
//usage:     "\n    -t,--tabs=N Tabstops every N chars"
//usage:    )
//usage:    IF_NOT_FEATURE_EXPAND_LONG_OPTIONS(
//usage:     "\n    -i  Don't convert tabs after non blanks"
//usage:     "\n    -t  Tabstops every N chars"
//usage:    )

//usage:#define unexpand_trivial_usage
//usage:       "[-fa][-t N] [FILE]..."
//usage:#define unexpand_full_usage "\n\n"
//usage:       "Convert spaces to tabs, writing to stdout\n"
//usage:    IF_FEATURE_UNEXPAND_LONG_OPTIONS(
//usage:     "\n    -a,--all    Convert all blanks"
//usage:     "\n    -f,--first-only Convert only leading blanks"
//usage:     "\n    -t,--tabs=N Tabstops every N chars"
//usage:    )
//usage:    IF_NOT_FEATURE_UNEXPAND_LONG_OPTIONS(
//usage:     "\n    -a  Convert all blanks"
//usage:     "\n    -f  Convert only leading blanks"
//usage:     "\n    -t N    Tabstops every N chars"
//usage:    )

#include "libbb.h"
#include "unicode.h"

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

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

    while ((line = xmalloc_fgets(file)) != NULL) {
        unsigned char c;
        char *ptr;
        char *ptr_strbeg;

        ptr = ptr_strbeg = line;
        while ((c = *ptr) != '\0') {
            if ((opt & OPT_INITIAL) && !isblank(c)) {
                /* not space or tab */
                break;
            }
            if (c == '\t') {
                unsigned len;
                *ptr = '\0';
# if ENABLE_UNICODE_SUPPORT
                len = unicode_strwidth(ptr_strbeg);
# else
                len = ptr - ptr_strbeg;
# endif
                len = tab_size - (len % tab_size);
                /*while (ptr[1] == '\t') { ptr++; len += tab_size; } - can handle many tabs at once */
                printf("%s%*s", ptr_strbeg, len, "");
                ptr_strbeg = ptr + 1;
            }
            ptr++;
        }
        fputs(ptr_strbeg, stdout);
        free(line);
    }
}
#endif

#if ENABLE_UNEXPAND
static void unexpand(FILE *file, unsigned tab_size, unsigned opt)
{
    char *line;

    while ((line = xmalloc_fgets(file)) != NULL) {
        char *ptr = line;
        unsigned column = 0;

        while (*ptr) {
            unsigned n;
            unsigned len = 0;

            while (*ptr == ' ') {
                ptr++;
                len++;
            }
            column += len;
            if (*ptr == '\t') {
                column += tab_size - (column % tab_size);
                ptr++;
                continue;
            }

            n = column / tab_size;
            if (n) {
                len = column = column % tab_size;
                while (n--)
                    putchar('\t');
            }

            if ((opt & OPT_INITIAL) && ptr != line) {
                printf("%*s%s", len, "", ptr);
                break;
            }
            n = strcspn(ptr, "\t ");
            printf("%*s%.*s", len, "", n, ptr);
# if ENABLE_UNICODE_SUPPORT
            {
                char c = ptr[n];
                ptr[n] = '\0';
                len = unicode_strwidth(ptr);
                ptr[n] = c;
            }
# else
            len = n;
# endif
            ptr += n;
            column = (column + len) % tab_size;
        }
        free(line);
    }
}
#endif

int expand_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int expand_main(int argc UNUSED_PARAM, 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
    init_unicode();

    if (ENABLE_EXPAND && (!ENABLE_UNEXPAND || applet_name[0] == 'e')) {
        IF_FEATURE_EXPAND_LONG_OPTIONS(applet_long_options = expand_longopts);
        opt = getopt32(argv, "it:", &opt_t);
    } else {
        IF_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 (!*argv) {
        *--argv = (char*)bb_msg_standard_input;
    }
    do {
        file = fopen_or_warn_stdin(*argv);
        if (!file) {
            exit_status = EXIT_FAILURE;
            continue;
        }

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

        /* Check and close the file */
        if (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);
}