cut.c

/*
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1989, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Adam S. Moskowitz of Menlo Consulting and Marciano Pitargue.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>

static int	bflag;
static int	cflag;
static wchar_t	dchar;
static char	dcharmb[MB_LEN_MAX + 1];
static int	dflag;
static int	fflag;
static int	nflag;
static int	sflag;
static int	wflag;

static size_t	autostart, autostop, maxval;
static char *	positions;

static int	b_cut(FILE *, const char *);
static int	b_n_cut(FILE *, const char *);
static int	c_cut(FILE *, const char *);
static int	f_cut(FILE *, const char *);
static void	get_list(char *);
static int	is_delim(wchar_t);
static void	needpos(size_t);
static void	usage(void);

int
main(int argc, char *argv[])
{
	FILE *fp;
	int (*fcn)(FILE *, const char *);
	int ch, rval;
	size_t n;

	setlocale(LC_ALL, "");

	fcn = NULL;
	dchar = '\t';			/* default delimiter is \t */
	strcpy(dcharmb, "\t");

	while ((ch = getopt(argc, argv, "b:c:d:f:snw")) != -1)
		switch(ch) {
		case 'b':
			get_list(optarg);
			bflag = 1;
			break;
		case 'c':
			get_list(optarg);
			cflag = 1;
			break;
		case 'd':
			n = mbrtowc(&dchar, optarg, MB_LEN_MAX, NULL);
			if (dchar == '\0' || n != strlen(optarg))
				errx(1, "bad delimiter");
			strcpy(dcharmb, optarg);
			dflag = 1;
			break;
		case 'f':
			get_list(optarg);
			fflag = 1;
			break;
		case 's':
			sflag = 1;
			break;
		case 'n':
			nflag = 1;
			break;
		case 'w':
			wflag = 1;
			break;
		case '?':
		default:
			usage();
		}
	argc -= optind;
	argv += optind;

	if (fflag) {
		if (bflag || cflag || nflag || (wflag && dflag))
			usage();
	} else if (!(bflag || cflag) || dflag || sflag || wflag)
		usage();
	else if (!bflag && nflag)
		usage();

	if (fflag)
		fcn = f_cut;
	else if (cflag)
		fcn = MB_CUR_MAX > 1 ? c_cut : b_cut;
	else if (bflag)
		fcn = nflag && MB_CUR_MAX > 1 ? b_n_cut : b_cut;

	rval = 0;
	if (*argv)
		for (; *argv; ++argv) {
			if (strcmp(*argv, "-") == 0)
				rval |= fcn(stdin, "stdin");
			else {
				if (!(fp = fopen(*argv, "r"))) {
					warn("%s", *argv);
					rval = 1;
					continue;
				}
				fcn(fp, *argv);
				(void)fclose(fp);
			}
		}
	else
		rval = fcn(stdin, "stdin");
	exit(rval);
}

static void
get_list(char *list)
{
	size_t setautostart, start, stop;
	char *pos;
	char *p;

	/*
	 * set a byte in the positions array to indicate if a field or
	 * column is to be selected; use +1, it's 1-based, not 0-based.
	 * Numbers and number ranges may be overlapping, repeated, and in
	 * any order. We handle "-3-5" although there's no real reason to.
	 */
	for (; (p = strsep(&list, ", \t")) != NULL;) {
		setautostart = start = stop = 0;
		if (*p == '-') {
			++p;
			setautostart = 1;
		}
		if (isdigit((unsigned char)*p)) {
			start = stop = strtol(p, &p, 10);
			if (setautostart && start > autostart)
				autostart = start;
		}
		if (*p == '-') {
			if (isdigit((unsigned char)p[1]))
				stop = strtol(p + 1, &p, 10);
			if (*p == '-') {
				++p;
				if (!autostop || autostop > stop)
					autostop = stop;
			}
		}
		if (*p)
			errx(1, "[-bcf] list: illegal list value");
		if (!stop || !start)
			errx(1, "[-bcf] list: values may not include zero");
		if (maxval < stop) {
			maxval = stop;
			needpos(maxval + 1);
		}
		for (pos = positions + start; start++ <= stop; *pos++ = 1);
	}

	/* overlapping ranges */
	if (autostop && maxval > autostop) {
		maxval = autostop;
		needpos(maxval + 1);
	}

	/* reversed range with autostart */
	if (maxval < autostart) {
		maxval = autostart;
		needpos(maxval + 1);
	}

	/* set autostart */
	if (autostart)
		memset(positions + 1, '1', autostart);
}

static void
needpos(size_t n)
{
	static size_t npos;
	size_t oldnpos;

	/* Grow the positions array to at least the specified size. */
	if (n > npos) {
		oldnpos = npos;
		if (npos == 0)
			npos = n;
		while (n > npos)
			npos *= 2;
		if ((positions = realloc(positions, npos)) == NULL)
			err(1, "realloc");
		memset((char *)positions + oldnpos, 0, npos - oldnpos);
	}
}

static int
b_cut(FILE *fp, const char *fname __unused)
{
	int ch, col;
	char *pos;

	ch = 0;
	for (;;) {
		pos = positions + 1;
		for (col = maxval; col; --col) {
			if ((ch = getc(fp)) == EOF)
				return (0);
			if (ch == '\n')
				break;
			if (*pos++)
				(void)putchar(ch);
		}
		if (ch != '\n') {
			if (autostop)
				while ((ch = getc(fp)) != EOF && ch != '\n')
					(void)putchar(ch);
			else
				while ((ch = getc(fp)) != EOF && ch != '\n');
		}
		(void)putchar('\n');
	}
	return (0);
}

/*
 * Cut based on byte positions, taking care not to split multibyte characters.
 * Although this function also handles the case where -n is not specified,
 * b_cut() ought to be much faster.
 */
static int
b_n_cut(FILE *fp, const char *fname)
{
	size_t col, i, bufsize = 0;
	ssize_t lbuflen;
	char *lbuf = NULL;
	int canwrite, clen, warned;
	mbstate_t mbs;

	memset(&mbs, 0, sizeof(mbs));
	warned = 0;
	while ((lbuflen = getline(&lbuf, &bufsize, fp)) >= 0) {
		for (col = 0; lbuflen > 0; col += clen) {
			if ((clen = mbrlen(lbuf, lbuflen, &mbs)) < 0) {
				if (!warned) {
					warn("%s", fname);
					warned = 1;
				}
				memset(&mbs, 0, sizeof(mbs));
				clen = 1;
			}
			if (clen == 0 || *lbuf == '\n')
				break;
			if (col < maxval && !positions[1 + col]) {
				/*
				 * Print the character if (1) after an initial
				 * segment of un-selected bytes, the rest of
				 * it is selected, and (2) the last byte is
				 * selected.
				 */
				i = col;
				while (i < col + clen && i < maxval &&
				    !positions[1 + i])
					i++;
				canwrite = i < col + clen;
				for (; i < col + clen && i < maxval; i++)
					canwrite &= positions[1 + i];
				if (canwrite)
					fwrite(lbuf, 1, clen, stdout);
			} else {
				/*
				 * Print the character if all of it has
				 * been selected.
				 */
				canwrite = 1;
				for (i = col; i < col + clen; i++)
					if ((i >= maxval && !autostop) ||
					    (i < maxval && !positions[1 + i])) {
						canwrite = 0;
						break;
					}
				if (canwrite)
					fwrite(lbuf, 1, clen, stdout);
			}
			lbuf += clen;
			lbuflen -= clen;
		}
		if (lbuflen > 0)
			putchar('\n');
	}
	free(lbuf);
	return (warned);
}

static int
c_cut(FILE *fp, const char *fname)
{
	wint_t ch;
	int col;
	char *pos;

	ch = 0;
	for (;;) {
		pos = positions + 1;
		for (col = maxval; col; --col) {
			if ((ch = getwc(fp)) == WEOF)
				goto out;
			if (ch == '\n')
				break;
			if (*pos++)
				(void)putwchar(ch);
		}
		if (ch != '\n') {
			if (autostop)
				while ((ch = getwc(fp)) != WEOF && ch != '\n')
					(void)putwchar(ch);
			else
				while ((ch = getwc(fp)) != WEOF && ch != '\n');
		}
		(void)putwchar('\n');
	}
out:
	if (ferror(fp)) {
		warn("%s", fname);
		return (1);
	}
	return (0);
}

static int
is_delim(wchar_t ch)
{
	if (wflag) {
		if (ch == ' ' || ch == '\t')
			return 1;
	} else {
		if (ch == dchar)
			return 1;
	}
	return 0;
}

static int
f_cut(FILE *fp, const char *fname)
{
	wchar_t ch;
	int field, i, isdelim;
	char *pos, *p;
	int output;
	char *lbuf = NULL;
	size_t clen, bufsize = 0, reallen;
	ssize_t lbuflen;

	while ((lbuflen = getline(&lbuf, &bufsize, fp)) >= 0) {
		reallen = lbuflen;
		/* Assert EOL has a newline. */
		if (lbuflen > 0 && *(lbuf + lbuflen - 1) != '\n') {
			/* Can't have > 1 line with no trailing newline. */
			if ((ssize_t)bufsize < (lbuflen + 1)) {
				bufsize = lbuflen + 1;
				lbuf = realloc(lbuf, bufsize);
			}
			if (lbuf == NULL)
				err(1, "realloc");
			lbuf[lbuflen] = '\n';
			reallen++;
		}
		output = 0;
		for (isdelim = 0, p = lbuf;; p += clen) {
			clen = mbrtowc(&ch, p, lbuf + reallen - p, NULL);
			if (clen == (size_t)-1 || clen == (size_t)-2) {
				warnc(EILSEQ, "%s", fname);
				free(lbuf);
				return (1);
			}
			if (clen == 0)
				clen = 1;
			/* this should work if newline is delimiter */
			if (is_delim(ch))
				isdelim = 1;
			if (ch == '\n') {
				if (!isdelim && !sflag)
					(void)fwrite(lbuf, lbuflen, 1, stdout);
				break;
			}
		}
		if (!isdelim)
			continue;

		pos = positions + 1;
		for (field = maxval, p = lbuf; field; --field, ++pos) {
			if (*pos && output++)
				for (i = 0; dcharmb[i] != '\0'; i++)
					putchar(dcharmb[i]);
			for (;;) {
				clen = mbrtowc(&ch, p, lbuf + reallen - p,
				    NULL);
				if (clen == (size_t)-1 || clen == (size_t)-2) {
					warnc(EILSEQ, "%s", fname);
					free(lbuf);
					return (1);
				}
				if (clen == 0)
					clen = 1;
				p += clen;
				if (ch == '\n' || is_delim(ch)) {
					/* compress whitespace */
					if (wflag && ch != '\n')
						while (is_delim(*p))
							p++;
					break;
				}
				if (*pos)
					for (i = 0; i < (int)clen; i++)
						putchar(p[i - clen]);
			}
			if (ch == '\n')
				break;
		}
		if (ch != '\n') {
			if (autostop) {
				if (output)
					for (i = 0; dcharmb[i] != '\0'; i++)
						putchar(dcharmb[i]);
				for (; (ch = *p) != '\n'; ++p)
					(void)putchar(ch);
			} else
				for (; (ch = *p) != '\n'; ++p);
		}
		(void)putchar('\n');
	}
	free(lbuf);
	return (0);
}

static void
usage(void)
{
	(void)fprintf(stderr, "%s\n%s\n%s\n",
		"usage: cut -b list [-n] [file ...]",
		"       cut -c list [file ...]",
		"       cut -f list [-s] [-w | -d delim] [file ...]");
	exit(1);
}