source: MondoRescue/branches/2.2.2/mindi-busybox/coreutils/cut.c@ 1247

/* vi: set sw=8 ts=8: */
/*
 * cut.c - minimalist version of cut
 *
 * Copyright (C) 1999,2000,2001 by Lineo, inc.
 * Written by Mark Whitley <markw@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
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <limits.h>
#include "busybox.h"


/* option vars */
static const char optstring[] = "b:c:f:d:sn";
#define OPT_BYTE_FLGS    1
#define OPT_CHAR_FLGS    2
#define OPT_FIELDS_FLGS  4
#define OPT_DELIM_FLGS   8
#define OPT_SUPRESS_FLGS 16
static char part; /* (b)yte, (c)har, (f)ields */
static unsigned int supress_non_delimited_lines;
static char delim = '\t'; /* delimiter, default is tab */

struct cut_list {
    int startpos;
    int endpos;
};

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

static struct cut_list *cut_lists = NULL; /* growable array holding a series of lists */
static unsigned int nlists = 0; /* number of elements in above list */


static int cmpfunc(const void *a, const void *b)
{
    struct cut_list *la = (struct cut_list *)a;
    struct cut_list *lb = (struct cut_list *)b;

    if (la->startpos > lb->startpos)
        return 1;
    if (la->startpos < lb->startpos)
        return -1;
    return 0;
}


/*
 * parse_lists() - parses a list and puts values into startpos and endpos.
 * valid list formats: N, N-, N-M, -M
 * more than one list can be separated by commas
 */
static void parse_lists(char *lists)
{
    char *ltok = NULL;
    char *ntok = NULL;
    char *junk;
    int s = 0, e = 0;

    /* take apart the lists, one by one (they are separated with commas */
    while ((ltok = strsep(&lists, ",")) != 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) {
            fprintf(stderr, "Help ntok is null for starting position! What do I do?\n");
        } else if (strlen(ntok) == 0) {
            s = BOL;
        } else {
            s = strtoul(ntok, &junk, 10);
            if(*junk != '\0' || s < 0)
                bb_error_msg_and_die("invalid byte or field list");

            /* 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 = strtoul(ntok, &junk, 10);
            if(*junk != '\0' || e < 0)
                bb_error_msg_and_die("invalid byte or field list");
            /* if the user specified and end position of 0, that means "til the
             * end of the line */
            if (e == 0)
                e = INT_MAX;
            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 past 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);

}


static void cut_line_by_chars(const char *line)
{
    int c, l;
    /* set up a list so we can keep track of what's been printed */
    char *printed = xcalloc(strlen(line), sizeof(char));

    /* print the chars specified in each cut list */
    for (c = 0; c < nlists; c++) {
        l = cut_lists[c].startpos;
        while (l < strlen(line)) {
            if (!printed[l]) {
                putchar(line[l]);
                printed[l] = 'X';
            }
            l++;
            if (cut_lists[c].endpos == NON_RANGE || l > cut_lists[c].endpos)
                break;
        }
    }
    putchar('\n'); /* cuz we were handed a chomped line */
    free(printed);
}


static void cut_line_by_fields(char *line)
{
    int c, f;
    int ndelim = -1; /* zero-based / one-based problem */
    int nfields_printed = 0;
    char *field = NULL;
    char d[2] = { delim, 0 };
    char *printed;

    /* test the easy case first: does this line contain any delimiters? */
    if (strchr(line, delim) == NULL) {
        if (!supress_non_delimited_lines)
            puts(line);
        return;
    }

    /* set up a list so we can keep track of what's been printed */
    printed = xcalloc(strlen(line), sizeof(char));

    /* process each list on this line, for as long as we've got a line to process */
    for (c = 0; c < nlists && line; c++) {
        f = cut_lists[c].startpos;
        do {

            /* find the field we're looking for */
            while (line && ndelim < f) {
                field = strsep(&line, d);
                ndelim++;
            }

            /* we found it, and it hasn't been printed yet */
            if (field && ndelim == f && !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++;
            }

            f++;

            /* 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 (line && cut_lists[c].endpos != NON_RANGE && f <= cut_lists[c].endpos);
    }

    /* if we printed anything at all, we need to finish it with a newline cuz
     * we were handed a chomped line */
    putchar('\n');

    free(printed);
}


static void cut_file_by_lines(const char *line, unsigned int linenum)
{
    static int c = 0;
    static int l = -1;

    /* I can't initialize this above cuz the "initializer isn't
     * constant" *sigh* */
    if (l == -1)
        l = cut_lists[c].startpos;

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

    /* 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 (l < linenum) {
        l++;
        /* move on to the next list if we're at the end of this one */
        if (cut_lists[c].endpos == NON_RANGE || l > cut_lists[c].endpos) {
            c++;
            /* get out if there's no more lists to process */
            if (c >= nlists)
                return;
            l = cut_lists[c].startpos;
            /* get out if the current line is lower than the one we just became
             * interested in */
            if (linenum < l)
                return;
        }
    }

    /* If we made it here, it means we've found the line we're looking for, so print it */
    puts(line);
}


/*
 * snippy-snip
 */
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 = bb_get_chomped_line_from_file(file)) != NULL) {

        /* cut based on chars/bytes XXX: only works when sizeof(char) == byte */
        if ((part & (OPT_CHAR_FLGS | OPT_BYTE_FLGS)))
            cut_line_by_chars(line);

        /* cut based on fields */
        else {
            if (delim == '\n')
                cut_file_by_lines(line, linenum);
            else
                cut_line_by_fields(line);
        }

        linenum++;
        free(line);
    }
}


int cut_main(int argc, char **argv)
{
    unsigned long opt;
    char *sopt, *sdopt;

    bb_opt_complementally = "b--bcf:c--bcf:f--bcf";
    opt = bb_getopt_ulflags(argc, argv, optstring, &sopt, &sopt, &sopt, &sdopt);
    part = opt & (OPT_BYTE_FLGS|OPT_CHAR_FLGS|OPT_FIELDS_FLGS);
    if(part == 0)
        bb_error_msg_and_die("you must specify a list of bytes, characters, or fields");
    if(opt & BB_GETOPT_ERROR)
        bb_error_msg_and_die("only one type of list may be specified");
    parse_lists(sopt);
    if((opt & (OPT_DELIM_FLGS))) {
        if (strlen(sdopt) > 1) {
            bb_error_msg_and_die("the delimiter must be a single character");
        }
        delim = sdopt[0];
    }
    supress_non_delimited_lines = opt & OPT_SUPRESS_FLGS;

    /*  non-field (char or byte) cutting has some special handling */
    if (part != OPT_FIELDS_FLGS) {
        if (supress_non_delimited_lines) {
            bb_error_msg_and_die("suppressing non-delimited lines makes sense"
                    " only when operating on fields");
        }
        if (delim != '\t') {
            bb_error_msg_and_die("a delimiter may be specified only when operating on fields");
        }
    }

    /* argv[(optind)..(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[optind] == NULL || (strcmp(argv[optind], "-") == 0)) {
        cut_file(stdin);
    }
    else {
        int i;
        FILE *file;
        for (i = optind; i < argc; i++) {
            file = bb_wfopen(argv[i], "r");
            if(file) {
                cut_file(file);
                fclose(file);
            }
        }
    }

    return EXIT_SUCCESS;
}