/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1988, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * 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 <sys/types.h>
#include <sys/capsicum.h>

#include <capsicum_helpers.h>
#include <ctype.h>
#include <err.h>
#include <limits.h>
#include <locale.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <wchar.h>
#include <wctype.h>

#include "cmap.h"
#include "cset.h"
#include "extern.h"

static STR s1 = { STRING1, NORMAL, 0, OOBCH, 0, { 0, OOBCH }, NULL, NULL };
static STR s2 = { STRING2, NORMAL, 0, OOBCH, 0, { 0, OOBCH }, NULL, NULL };

static struct cset *setup(char *, STR *, int, int);
static void usage(void) __dead2;

int
main(int argc, char **argv)
{
        static int carray[NCHARS_SB];
        struct cmap *map;
        struct cset *delete, *squeeze;
        int n, *p;
        int Cflag, cflag, dflag, sflag, isstring2;
        wint_t ch, cnt, lastch;

        (void)setlocale(LC_ALL, "");

        if (caph_limit_stdio() == -1)
                err(1, "unable to limit stdio");

        if (caph_enter() < 0)
                err(1, "unable to enter capability mode");

        Cflag = cflag = dflag = sflag = 0;
        while ((ch = getopt(argc, argv, "Ccdsu")) != -1)
                switch((char)ch) {
                case 'C':
                        Cflag = 1;
                        cflag = 0;
                        break;
                case 'c':
                        cflag = 1;
                        Cflag = 0;
                        break;
                case 'd':
                        dflag = 1;
                        break;
                case 's':
                        sflag = 1;
                        break;
                case 'u':
                        setbuf(stdout, (char *)NULL);
                        break;
                case '?':
                default:
                        usage();
                }
        argc -= optind;
        argv += optind;

        switch(argc) {
        case 0:
        default:
                usage();
                /* NOTREACHED */
        case 1:
                isstring2 = 0;
                break;
        case 2:
                isstring2 = 1;
                break;
        }

        /*
         * tr -ds [-Cc] string1 string2
         * Delete all characters (or complemented characters) in string1.
         * Squeeze all characters in string2.
         */
        if (dflag && sflag) {
                if (!isstring2)
                        usage();

                delete = setup(argv[0], &s1, cflag, Cflag);
                squeeze = setup(argv[1], &s2, 0, 0);

                for (lastch = OOBCH; (ch = getwchar()) != WEOF;)
                        if (!cset_in(delete, ch) &&
                            (lastch != ch || !cset_in(squeeze, ch))) {
                                lastch = ch;
                                (void)putwchar(ch);
                        }
                if (ferror(stdin))
                        err(1, NULL);
                exit(0);
        }

        /*
         * tr -d [-Cc] string1
         * Delete all characters (or complemented characters) in string1.
         */
        if (dflag) {
                if (isstring2)
                        usage();

                delete = setup(argv[0], &s1, cflag, Cflag);

                while ((ch = getwchar()) != WEOF)
                        if (!cset_in(delete, ch))
                                (void)putwchar(ch);
                if (ferror(stdin))
                        err(1, NULL);
                exit(0);
        }

        /*
         * tr -s [-Cc] string1
         * Squeeze all characters (or complemented characters) in string1.
         */
        if (sflag && !isstring2) {
                squeeze = setup(argv[0], &s1, cflag, Cflag);

                for (lastch = OOBCH; (ch = getwchar()) != WEOF;)
                        if (lastch != ch || !cset_in(squeeze, ch)) {
                                lastch = ch;
                                (void)putwchar(ch);
                        }
                if (ferror(stdin))
                        err(1, NULL);
                exit(0);
        }

        /*
         * tr [-Ccs] string1 string2
         * Replace all characters (or complemented characters) in string1 with
         * the character in the same position in string2.  If the -s option is
         * specified, squeeze all the characters in string2.
         */
        if (!isstring2)
                usage();

        map = cmap_alloc();
        if (map == NULL)
                err(1, NULL);
        squeeze = cset_alloc();
        if (squeeze == NULL)
                err(1, NULL);

        s1.str = argv[0];

        if (Cflag || cflag) {
                cmap_default(map, OOBCH);
                if ((s2.str = strdup(argv[1])) == NULL)
                        errx(1, "strdup(argv[1])");
        } else
                s2.str = argv[1];

        if (!next(&s2))
                errx(1, "empty string2");

        /*
         * For -s result will contain only those characters defined
         * as the second characters in each of the toupper or tolower
         * pairs.
         */

        /* If string2 runs out of characters, use the last one specified. */
        while (next(&s1)) {
        again:
                if (s1.state == CCLASS_LOWER &&
                    s2.state == CCLASS_UPPER &&
                    s1.cnt == 1 && s2.cnt == 1) {
                        do {
                                ch = towupper(s1.lastch);
                                cmap_add(map, s1.lastch, ch);
                                if (sflag && iswupper(ch))
                                        cset_add(squeeze, ch);
                                if (!next(&s1))
                                        goto endloop;
                        } while (s1.state == CCLASS_LOWER && s1.cnt > 1);
                        /* skip upper set */
                        do {
                                if (!next(&s2))
                                        break;
                        } while (s2.state == CCLASS_UPPER && s2.cnt > 1);
                        goto again;
                } else if (s1.state == CCLASS_UPPER &&
                           s2.state == CCLASS_LOWER &&
                           s1.cnt == 1 && s2.cnt == 1) {
                        do {
                                ch = towlower(s1.lastch);
                                cmap_add(map, s1.lastch, ch);
                                if (sflag && iswlower(ch))
                                        cset_add(squeeze, ch);
                                if (!next(&s1))
                                        goto endloop;
                        } while (s1.state == CCLASS_UPPER && s1.cnt > 1);
                        /* skip lower set */
                        do {
                                if (!next(&s2))
                                        break;
                        } while (s2.state == CCLASS_LOWER && s2.cnt > 1);
                        goto again;
                } else if (s1.state == CCLASS &&
                           s2.state == CCLASS_UPPER &&
                           s1.cnt == 1 && s2.cnt == 1) {
                        do {
                                ch = towupper(s1.lastch);
                                cmap_add(map, s1.lastch, ch);
                                if (sflag && iswupper(ch))
                                        cset_add(squeeze, ch);
                                if (!next(&s1))
                                        goto endloop;
                        } while (s1.state == CCLASS && s1.cnt > 1);
                        /* skip upper set */
                        do {
                                if (!next(&s2))
                                        break;
                        } while (s2.state == CCLASS_UPPER && s2.cnt > 1);
                        goto again;
                } else if (s1.state == CCLASS &&
                           s2.state == CCLASS_LOWER &&
                           s1.cnt == 1 && s2.cnt == 1) {
                        do {
                                ch = towlower(s1.lastch);
                                cmap_add(map, s1.lastch, ch);
                                if (sflag && iswlower(ch))
                                        cset_add(squeeze, ch);
                                if (!next(&s1))
                                        goto endloop;
                        } while (s1.state == CCLASS && s1.cnt > 1);
                        /* skip lower set */
                        do {
                                if (!next(&s2))
                                        break;
                        } while (s2.state == CCLASS_LOWER && s2.cnt > 1);
                        goto again;
                } else {
                        cmap_add(map, s1.lastch, s2.lastch);
                        if (sflag)
                                cset_add(squeeze, s2.lastch);
                }
                (void)next(&s2);
        }
endloop:
        if (cflag || (Cflag && MB_CUR_MAX > 1)) {
                /*
                 * This is somewhat tricky: since the character set is
                 * potentially huge, we need to avoid allocating a map
                 * entry for every character. Our strategy is to set the
                 * default mapping to the last character of string #2
                 * (= the one that gets automatically repeated), then to
                 * add back identity mappings for characters that should
                 * remain unchanged. We don't waste space on identity mappings
                 * for non-characters with the -C option; those are simulated
                 * in the I/O loop.
                 */
                s2.str = argv[1];
                s2.state = NORMAL;
                for (cnt = 0; cnt < WINT_MAX; cnt++) {
                        if (Cflag && !iswrune(cnt))
                                continue;
                        if (cmap_lookup(map, cnt) == OOBCH) {
                                if (next(&s2)) {
                                        cmap_add(map, cnt, s2.lastch);
                                        if (sflag)
                                                cset_add(squeeze, s2.lastch);
                                }
                        } else
                                cmap_add(map, cnt, cnt);
                        if ((s2.state == EOS || s2.state == INFINITE) &&
                            cnt >= cmap_max(map))
                                break;
                }
                cmap_default(map, s2.lastch);
        } else if (Cflag) {
                for (p = carray, cnt = 0; cnt < NCHARS_SB; cnt++) {
                        if (cmap_lookup(map, cnt) == OOBCH && iswrune(cnt))
                                *p++ = cnt;
                        else
                                cmap_add(map, cnt, cnt);
                }
                n = p - carray;
                if (Cflag && n > 1)
                        (void)mergesort(carray, n, sizeof(*carray), charcoll);

                s2.str = argv[1];
                s2.state = NORMAL;
                for (cnt = 0; cnt < n; cnt++) {
                        (void)next(&s2);
                        cmap_add(map, carray[cnt], s2.lastch);
                        /*
                         * Chars taken from s2 can be different this time
                         * due to lack of complex upper/lower processing,
                         * so fill string2 again to not miss some.
                         */
                        if (sflag)
                                cset_add(squeeze, s2.lastch);
                }
        }

        cset_cache(squeeze);
        cmap_cache(map);

        if (sflag)
                for (lastch = OOBCH; (ch = getwchar()) != WEOF;) {
                        if (!Cflag || iswrune(ch))
                                ch = cmap_lookup(map, ch);
                        if (lastch != ch || !cset_in(squeeze, ch)) {
                                lastch = ch;
                                (void)putwchar(ch);
                        }
                }
        else
                while ((ch = getwchar()) != WEOF) {
                        if (!Cflag || iswrune(ch))
                                ch = cmap_lookup(map, ch);
                        (void)putwchar(ch);
                }
        if (ferror(stdin))
                err(1, NULL);
        exit (0);
}

static struct cset *
setup(char *arg, STR *str, int cflag, int Cflag)
{
        struct cset *cs;

        cs = cset_alloc();
        if (cs == NULL)
                err(1, NULL);
        str->str = arg;
        while (next(str))
                cset_add(cs, str->lastch);
        if (Cflag)
                cset_addclass(cs, wctype("rune"), true);
        if (cflag || Cflag)
                cset_invert(cs);
        cset_cache(cs);
        return (cs);
}

int
charcoll(const void *a, const void *b)
{
        static char sa[2], sb[2];

        sa[0] = *(const int *)a;
        sb[0] = *(const int *)b;
        return (strcoll(sa, sb));
}

static void
usage(void)
{
        (void)fprintf(stderr, "%s\n%s\n%s\n%s\n",
                "usage: tr [-Ccsu] string1 string2",
                "       tr [-Ccu] -d string1",
                "       tr [-Ccu] -s string1",
                "       tr [-Ccu] -ds string1 string2");
        exit(1);
}