busybox/coreutils/cut.c

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/* 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)
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 delim)
{
char *line = NULL;
unsigned int linenum = 0; /* keep these zero-based to be consistent */
/* go through every line in the file */
while ((line = xmalloc_fgetline(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 */
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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) {
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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');
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next_line:
linenum++;
free(printed);
free(orig_line);
}
}
int cut_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int cut_main(int argc ATTRIBUTE_UNUSED, char **argv)
{
char delim = '\t'; /* delimiter, default is tab */
char *sopt, *ltok;
opt_complementary = "b--bcf:c--bcf:f--bcf";
getopt32(argv, optstring, &sopt, &sopt, &sopt, &ltok);
// argc -= optind;
argv += optind;
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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");
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if (option_mask32 & CUT_OPT_DELIM_FLGS) {
if (ltok[0] && ltok[1]) { /* more than 1 char? */
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 */
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if (!(option_mask32 & CUT_OPT_FIELDS_FLGS)) {
static const char _op_on_field[] ALIGN1 = " only when operating on fields";
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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 (!ltok[0])
continue;
/* get the start pos */
ntok = strsep(&ltok, "-");
if (!ntok[0]) {
s = BOL;
} else {
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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 */
if (ltok == NULL) {
e = NON_RANGE;
} else if (!ltok[0]) {
e = EOL;
} else {
e = xatoi_u(ltok);
/* 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;
}
/* add the new list */
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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);
}
{
int retval = EXIT_SUCCESS;
if (!*argv)
*--argv = (char *)"-";
do {
FILE *file = fopen_or_warn_stdin(*argv);
if (!file) {
retval = EXIT_FAILURE;
continue;
}
cut_file(file, delim);
fclose_if_not_stdin(file);
} while (*++argv);
if (ENABLE_FEATURE_CLEAN_UP)
free(cut_lists);
fflush_stdout_and_exit(retval);
}
}