LXR busybox/coreutils/cut.c

   1/* vi: set sw=4 ts=4: */
   2/*
   3 * cut.c - minimalist version of cut
   4 *
   5 * Copyright (C) 1999,2000,2001 by Lineo, inc.
   6 * Written by Mark Whitley <markw@codepoet.org>
   7 * debloated by Bernhard Reutner-Fischer
   8 *
   9 * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  10 */
  11//config:config CUT
  12//config:       bool "cut (5.8 kb)"
  13//config:       default y
  14//config:       help
  15//config:       cut is used to print selected parts of lines from
  16//config:       each file to stdout.
  17
  18//applet:IF_CUT(APPLET_NOEXEC(cut, cut, BB_DIR_USR_BIN, BB_SUID_DROP, cut))
  19
  20//kbuild:lib-$(CONFIG_CUT) += cut.o
  21
  22//usage:#define cut_trivial_usage
  23//usage:       "[OPTIONS] [FILE]..."
  24//usage:#define cut_full_usage "\n\n"
  25//usage:       "Print selected fields from each input FILE to stdout\n"
  26//usage:     "\n        -b LIST Output only bytes from LIST"
  27//usage:     "\n        -c LIST Output only characters from LIST"
  28//usage:     "\n        -d CHAR Use CHAR instead of tab as the field delimiter"
  29//usage:     "\n        -s      Output only the lines containing delimiter"
  30//usage:     "\n        -f N    Print only these fields"
  31//usage:     "\n        -n      Ignored"
  32//usage:
  33//usage:#define cut_example_usage
  34//usage:       "$ echo \"Hello world\" | cut -f 1 -d ' '\n"
  35//usage:       "Hello\n"
  36//usage:       "$ echo \"Hello world\" | cut -f 2 -d ' '\n"
  37//usage:       "world\n"
  38
  39#include "libbb.h"
  40
  41/* This is a NOEXEC applet. Be very careful! */
  42
  43
  44/* option vars */
  45#define OPT_STR "b:c:f:d:sn"
  46#define CUT_OPT_BYTE_FLGS     (1 << 0)
  47#define CUT_OPT_CHAR_FLGS     (1 << 1)
  48#define CUT_OPT_FIELDS_FLGS   (1 << 2)
  49#define CUT_OPT_DELIM_FLGS    (1 << 3)
  50#define CUT_OPT_SUPPRESS_FLGS (1 << 4)
  51
  52struct cut_list {
  53        int startpos;
  54        int endpos;
  55};
  56
  57enum {
  58        BOL = 0,
  59        EOL = INT_MAX,
  60        NON_RANGE = -1
  61};
  62
  63static int cmpfunc(const void *a, const void *b)
  64{
  65        return (((struct cut_list *) a)->startpos -
  66                        ((struct cut_list *) b)->startpos);
  67}
  68
  69static void cut_file(FILE *file, char delim, const struct cut_list *cut_lists, unsigned nlists)
  70{
  71        char *line;
  72        unsigned linenum = 0;   /* keep these zero-based to be consistent */
  73
  74        /* go through every line in the file */
  75        while ((line = xmalloc_fgetline(file)) != NULL) {
  76
  77                /* set up a list so we can keep track of what's been printed */
  78                int linelen = strlen(line);
  79                char *printed = xzalloc(linelen + 1);
  80                char *orig_line = line;
  81                unsigned cl_pos = 0;
  82                int spos;
  83
  84                /* cut based on chars/bytes XXX: only works when sizeof(char) == byte */
  85                if (option_mask32 & (CUT_OPT_CHAR_FLGS | CUT_OPT_BYTE_FLGS)) {
  86                        /* print the chars specified in each cut list */
  87                        for (; cl_pos < nlists; cl_pos++) {
  88                                spos = cut_lists[cl_pos].startpos;
  89                                while (spos < linelen) {
  90                                        if (!printed[spos]) {
  91                                                printed[spos] = 'X';
  92                                                putchar(line[spos]);
  93                                        }
  94                                        spos++;
  95                                        if (spos > cut_lists[cl_pos].endpos
  96                                        /* NON_RANGE is -1, so if below is true,
  97                                         * the above was true too (spos is >= 0) */
  98                                        /* || cut_lists[cl_pos].endpos == NON_RANGE */
  99                                        ) {
 100                                                break;
 101                                        }
 102                                }
 103                        }
 104                } else if (delim == '\n') {     /* cut by lines */
 105                        spos = cut_lists[cl_pos].startpos;
 106
 107                        /* get out if we have no more lists to process or if the lines
 108                         * are lower than what we're interested in */
 109                        if (((int)linenum < spos) || (cl_pos >= nlists))
 110                                goto next_line;
 111
 112                        /* if the line we're looking for is lower than the one we were
 113                         * passed, it means we displayed it already, so move on */
 114                        while (spos < (int)linenum) {
 115                                spos++;
 116                                /* go to the next list if we're at the end of this one */
 117                                if (spos > cut_lists[cl_pos].endpos
 118                                 || cut_lists[cl_pos].endpos == NON_RANGE
 119                                ) {
 120                                        cl_pos++;
 121                                        /* get out if there's no more lists to process */
 122                                        if (cl_pos >= nlists)
 123                                                goto next_line;
 124                                        spos = cut_lists[cl_pos].startpos;
 125                                        /* get out if the current line is lower than the one
 126                                         * we just became interested in */
 127                                        if ((int)linenum < spos)
 128                                                goto next_line;
 129                                }
 130                        }
 131
 132                        /* If we made it here, it means we've found the line we're
 133                         * looking for, so print it */
 134                        puts(line);
 135                        goto next_line;
 136                } else {                /* cut by fields */
 137                        int ndelim = -1;        /* zero-based / one-based problem */
 138                        int nfields_printed = 0;
 139                        char *field = NULL;
 140                        char delimiter[2];
 141
 142                        delimiter[0] = delim;
 143                        delimiter[1] = 0;
 144
 145                        /* does this line contain any delimiters? */
 146                        if (strchr(line, delim) == NULL) {
 147                                if (!(option_mask32 & CUT_OPT_SUPPRESS_FLGS))
 148                                        puts(line);
 149                                goto next_line;
 150                        }
 151
 152                        /* process each list on this line, for as long as we've got
 153                         * a line to process */
 154                        for (; cl_pos < nlists && line; cl_pos++) {
 155                                spos = cut_lists[cl_pos].startpos;
 156                                do {
 157                                        /* find the field we're looking for */
 158                                        while (line && ndelim < spos) {
 159                                                field = strsep(&line, delimiter);
 160                                                ndelim++;
 161                                        }
 162
 163                                        /* we found it, and it hasn't been printed yet */
 164                                        if (field && ndelim == spos && !printed[ndelim]) {
 165                                                /* if this isn't our first time through, we need to
 166                                                 * print the delimiter after the last field that was
 167                                                 * printed */
 168                                                if (nfields_printed > 0)
 169                                                        putchar(delim);
 170                                                fputs(field, stdout);
 171                                                printed[ndelim] = 'X';
 172                                                nfields_printed++;      /* shouldn't overflow.. */
 173                                        }
 174
 175                                        spos++;
 176
 177                                        /* keep going as long as we have a line to work with,
 178                                         * this is a list, and we're not at the end of that
 179                                         * list */
 180                                } while (spos <= cut_lists[cl_pos].endpos && line
 181                                                && cut_lists[cl_pos].endpos != NON_RANGE);
 182                        }
 183                }
 184                /* if we printed anything at all, we need to finish it with a
 185                 * newline cuz we were handed a chomped line */
 186                putchar('\n');
 187 next_line:
 188                linenum++;
 189                free(printed);
 190                free(orig_line);
 191        }
 192}
 193
 194int cut_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 195int cut_main(int argc UNUSED_PARAM, char **argv)
 196{
 197        /* growable array holding a series of lists */
 198        struct cut_list *cut_lists = NULL;
 199        unsigned nlists = 0;    /* number of elements in above list */
 200        char delim = '\t';      /* delimiter, default is tab */
 201        char *sopt, *ltok;
 202        unsigned opt;
 203
 204        opt = getopt32(argv, "^"
 205                        OPT_STR
 206                        "\0" "b--bcf:c--bcf:f--bcf",
 207                        &sopt, &sopt, &sopt, &ltok
 208        );
 209//      argc -= optind;
 210        argv += optind;
 211        if (!(opt & (CUT_OPT_BYTE_FLGS | CUT_OPT_CHAR_FLGS | CUT_OPT_FIELDS_FLGS)))
 212                bb_error_msg_and_die("expected a list of bytes, characters, or fields");
 213
 214        if (opt & CUT_OPT_DELIM_FLGS) {
 215                if (ltok[0] && ltok[1]) { /* more than 1 char? */
 216                        bb_error_msg_and_die("the delimiter must be a single character");
 217                }
 218                delim = ltok[0];
 219        }
 220
 221        /*  non-field (char or byte) cutting has some special handling */
 222        if (!(opt & CUT_OPT_FIELDS_FLGS)) {
 223                static const char _op_on_field[] ALIGN1 = " only when operating on fields";
 224
 225                if (opt & CUT_OPT_SUPPRESS_FLGS) {
 226                        bb_error_msg_and_die
 227                                ("suppressing non-delimited lines makes sense%s",
 228                                _op_on_field);
 229                }
 230                if (delim != '\t') {
 231                        bb_error_msg_and_die
 232                                ("a delimiter may be specified%s", _op_on_field);
 233                }
 234        }
 235
 236        /*
 237         * parse list and put values into startpos and endpos.
 238         * valid list formats: N, N-, N-M, -M
 239         * more than one list can be separated by commas
 240         */
 241        {
 242                char *ntok;
 243                int s = 0, e = 0;
 244
 245                /* take apart the lists, one by one (they are separated with commas) */
 246                while ((ltok = strsep(&sopt, ",")) != NULL) {
 247
 248                        /* it's actually legal to pass an empty list */
 249                        if (!ltok[0])
 250                                continue;
 251
 252                        /* get the start pos */
 253                        ntok = strsep(&ltok, "-");
 254                        if (!ntok[0]) {
 255                                s = BOL;
 256                        } else {
 257                                s = xatoi_positive(ntok);
 258                                /* account for the fact that arrays are zero based, while
 259                                 * the user expects the first char on the line to be char #1 */
 260                                if (s != 0)
 261                                        s--;
 262                        }
 263
 264                        /* get the end pos */
 265                        if (ltok == NULL) {
 266                                e = NON_RANGE;
 267                        } else if (!ltok[0]) {
 268                                e = EOL;
 269                        } else {
 270                                e = xatoi_positive(ltok);
 271                                /* if the user specified and end position of 0,
 272                                 * that means "til the end of the line" */
 273                                if (e == 0)
 274                                        e = EOL;
 275                                e--;    /* again, arrays are zero based, lines are 1 based */
 276                                if (e == s)
 277                                        e = NON_RANGE;
 278                        }
 279
 280                        /* add the new list */
 281                        cut_lists = xrealloc_vector(cut_lists, 4, nlists);
 282                        /* NB: startpos is always >= 0,
 283                         * while endpos may be = NON_RANGE (-1) */
 284                        cut_lists[nlists].startpos = s;
 285                        cut_lists[nlists].endpos = e;
 286                        nlists++;
 287                }
 288
 289                /* make sure we got some cut positions out of all that */
 290                if (nlists == 0)
 291                        bb_error_msg_and_die("missing list of positions");
 292
 293                /* now that the lists are parsed, we need to sort them to make life
 294                 * easier on us when it comes time to print the chars / fields / lines
 295                 */
 296                qsort(cut_lists, nlists, sizeof(cut_lists[0]), cmpfunc);
 297        }
 298
 299        {
 300                int retval = EXIT_SUCCESS;
 301
 302                if (!*argv)
 303                        *--argv = (char *)"-";
 304
 305                do {
 306                        FILE *file = fopen_or_warn_stdin(*argv);
 307                        if (!file) {
 308                                retval = EXIT_FAILURE;
 309                                continue;
 310                        }
 311                        cut_file(file, delim, cut_lists, nlists);
 312                        fclose_if_not_stdin(file);
 313                } while (*++argv);
 314
 315                if (ENABLE_FEATURE_CLEAN_UP)
 316                        free(cut_lists);
 317                fflush_stdout_and_exit(retval);
 318        }
 319}
 320