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>
*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#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)
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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)
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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)
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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)
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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 = xzalloc(strlen(line));
/* 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 = xzalloc(strlen(line));
/* 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 */
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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) {
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bb_error_msg_and_die("suppressing non-delimited lines makes sense"
" only when operating on fields");
}
if (delim != '\t') {
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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++) {
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file = bb_wfopen(argv[i], "r");
if(file) {
cut_file(file);
fclose(file);
}
}
}
return EXIT_SUCCESS;
}