source: MondoRescue/branches/stable/mindi-busybox/coreutils/cut.c@ 1770

/* vi: set sw=4 ts=4: */
/*
 * cut.c - minimalist version of cut
 *
 * Copyright (C) 1999,2000,2001 by Lineo, inc.
 * Written by Mark Whitley <markw@codepoet.org>
 * debloated by Bernhard Fischer
 *
 * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
 */

#include "libbb.h"

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


/* option vars */
static const char optstring[] ALIGN1 = "b:c:f:d:sn";
#define CUT_OPT_BYTE_FLGS   (1<<0)
#define CUT_OPT_CHAR_FLGS   (1<<1)
#define CUT_OPT_FIELDS_FLGS (1<<2)
#define CUT_OPT_DELIM_FLGS  (1<<3)
#define CUT_OPT_SUPPRESS_FLGS (1<<4)

static char delim = '\t';   /* delimiter, default is tab */

struct cut_list {
    int startpos;
    int endpos;
};

enum {
    BOL = 0,
    EOL = INT_MAX,
    NON_RANGE = -1
};

/* growable array holding a series of lists */
static struct cut_list *cut_lists;
static unsigned int nlists; /* number of elements in above list */


static int cmpfunc(const void *a, const void *b)
{
    return (((struct cut_list *) a)->startpos -
            ((struct cut_list *) b)->startpos);

}

static void cut_file(FILE * file)
{
    char *line = NULL;
    unsigned int linenum = 0;   /* keep these zero-based to be consistent */

    /* go through every line in the file */
    while ((line = xmalloc_getline(file)) != NULL) {

        /* set up a list so we can keep track of what's been printed */
        char * printed = xzalloc(strlen(line) * sizeof(char));
        char * orig_line = line;
        unsigned int cl_pos = 0;
        int spos;

        /* cut based on chars/bytes XXX: only works when sizeof(char) == byte */
        if (option_mask32 & (CUT_OPT_CHAR_FLGS | CUT_OPT_BYTE_FLGS)) {
            /* print the chars specified in each cut list */
            for (; cl_pos < nlists; cl_pos++) {
                spos = cut_lists[cl_pos].startpos;
                while (spos < strlen(line)) {
                    if (!printed[spos]) {
                        printed[spos] = 'X';
                        putchar(line[spos]);
                    }
                    spos++;
                    if (spos > cut_lists[cl_pos].endpos
                        || cut_lists[cl_pos].endpos == NON_RANGE)
                        break;
                }
            }
        } else if (delim == '\n') { /* cut by lines */
            spos = cut_lists[cl_pos].startpos;

            /* get out if we have no more lists to process or if the lines
             * are lower than what we're interested in */
            if (linenum < spos || cl_pos >= nlists)
                goto next_line;

            /* if the line we're looking for is lower than the one we were
             * passed, it means we displayed it already, so move on */
            while (spos < linenum) {
                spos++;
                /* go to the next list if we're at the end of this one */
                if (spos > cut_lists[cl_pos].endpos
                    || cut_lists[cl_pos].endpos == NON_RANGE) {
                    cl_pos++;
                    /* get out if there's no more lists to process */
                    if (cl_pos >= nlists)
                        goto next_line;
                    spos = cut_lists[cl_pos].startpos;
                    /* get out if the current line is lower than the one
                     * we just became interested in */
                    if (linenum < spos)
                        goto next_line;
                }
            }

            /* If we made it here, it means we've found the line we're
             * looking for, so print it */
            puts(line);
            goto next_line;
        } else {        /* cut by fields */
            int ndelim = -1;    /* zero-based / one-based problem */
            int nfields_printed = 0;
            char *field = NULL;
            const char delimiter[2] = { delim, 0 };

            /* does this line contain any delimiters? */
            if (strchr(line, delim) == NULL) {
                if (!(option_mask32 & CUT_OPT_SUPPRESS_FLGS))
                    puts(line);
                goto next_line;
            }

            /* process each list on this line, for as long as we've got
             * a line to process */
            for (; cl_pos < nlists && line; cl_pos++) {
                spos = cut_lists[cl_pos].startpos;
                do {
                    /* find the field we're looking for */
                    while (line && ndelim < spos) {
                        field = strsep(&line, delimiter);
                        ndelim++;
                    }

                    /* we found it, and it hasn't been printed yet */
                    if (field && ndelim == spos && !printed[ndelim]) {
                        /* if this isn't our first time through, we need to
                         * print the delimiter after the last field that was
                         * printed */
                        if (nfields_printed > 0)
                            putchar(delim);
                        fputs(field, stdout);
                        printed[ndelim] = 'X';
                        nfields_printed++;  /* shouldn't overflow.. */
                    }

                    spos++;

                    /* keep going as long as we have a line to work with,
                     * this is a list, and we're not at the end of that
                     * list */
                } while (spos <= cut_lists[cl_pos].endpos && line
                         && cut_lists[cl_pos].endpos != NON_RANGE);
            }
        }
        /* if we printed anything at all, we need to finish it with a
         * newline cuz we were handed a chomped line */
        putchar('\n');
 next_line:
        linenum++;
        free(printed);
        free(orig_line);
    }
}

static const char _op_on_field[] ALIGN1 = " only when operating on fields";

int cut_main(int argc, char **argv);
int cut_main(int argc, char **argv)
{
    char *sopt, *ltok;

    opt_complementary = "b--bcf:c--bcf:f--bcf";
    getopt32(argv, optstring, &sopt, &sopt, &sopt, &ltok);
//  argc -= optind;
    argv += optind;
    if (!(option_mask32 & (CUT_OPT_BYTE_FLGS | CUT_OPT_CHAR_FLGS | CUT_OPT_FIELDS_FLGS)))
        bb_error_msg_and_die("expected a list of bytes, characters, or fields");

    if (option_mask32 & CUT_OPT_DELIM_FLGS) {
        if (strlen(ltok) > 1) {
            bb_error_msg_and_die("the delimiter must be a single character");
        }
        delim = ltok[0];
    }

    /*  non-field (char or byte) cutting has some special handling */
    if (!(option_mask32 & CUT_OPT_FIELDS_FLGS)) {
        if (option_mask32 & CUT_OPT_SUPPRESS_FLGS) {
            bb_error_msg_and_die
                ("suppressing non-delimited lines makes sense%s",
                 _op_on_field);
        }
        if (delim != '\t') {
            bb_error_msg_and_die
                ("a delimiter may be specified%s", _op_on_field);
        }
    }

    /*
     * parse list and put values into startpos and endpos.
     * valid list formats: N, N-, N-M, -M
     * more than one list can be separated by commas
     */
    {
        char *ntok;
        int s = 0, e = 0;

        /* take apart the lists, one by one (they are separated with commas */
        while ((ltok = strsep(&sopt, ",")) != NULL) {

            /* it's actually legal to pass an empty list */
            if (strlen(ltok) == 0)
                continue;

            /* get the start pos */
            ntok = strsep(&ltok, "-");
            if (ntok == NULL) {
                bb_error_msg
                    ("internal error: ntok is null for start pos!?\n");
            } else if (strlen(ntok) == 0) {
                s = BOL;
            } else {
                s = xatoi_u(ntok);
                /* account for the fact that arrays are zero based, while
                 * the user expects the first char on the line to be char #1 */
                if (s != 0)
                    s--;
            }

            /* get the end pos */
            ntok = strsep(&ltok, "-");
            if (ntok == NULL) {
                e = NON_RANGE;
            } else if (strlen(ntok) == 0) {
                e = EOL;
            } else {
                e = xatoi_u(ntok);
                /* if the user specified and end position of 0, that means "til the
                 * end of the line */
                if (e == 0)
                    e = EOL;
                e--;    /* again, arrays are zero based, lines are 1 based */
                if (e == s)
                    e = NON_RANGE;
            }

            /* if there's something left to tokenize, the user passed
             * an invalid list */
            if (ltok)
                bb_error_msg_and_die("invalid byte or field list");

            /* add the new list */
            cut_lists = xrealloc(cut_lists, sizeof(struct cut_list) * (++nlists));
            cut_lists[nlists-1].startpos = s;
            cut_lists[nlists-1].endpos = e;
        }

        /* make sure we got some cut positions out of all that */
        if (nlists == 0)
            bb_error_msg_and_die("missing list of positions");

        /* now that the lists are parsed, we need to sort them to make life
         * easier on us when it comes time to print the chars / fields / lines
         */
        qsort(cut_lists, nlists, sizeof(struct cut_list), cmpfunc);
    }

    /* argv[0..argc-1] should be names of file to process. If no
     * files were specified or '-' was specified, take input from stdin.
     * Otherwise, we process all the files specified. */
    if (argv[0] == NULL || LONE_DASH(argv[0])) {
        cut_file(stdin);
    } else {
        FILE *file;

        do {
            file = fopen_or_warn(argv[0], "r");
            if (file) {
                cut_file(file);
                fclose(file);
            }
        } while (*++argv);
    }
    if (ENABLE_FEATURE_CLEAN_UP)
        free(cut_lists);
    return EXIT_SUCCESS;
}