/*      $NetBSD: uniq.c,v 1.22 2019/04/23 17:35:10 christos Exp $       */

/*
 * Copyright (c) 1989, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Case Larsen.
 *
 * 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/cdefs.h>
#ifndef lint
__COPYRIGHT("@(#) Copyright (c) 1989, 1993\
 The Regents of the University of California.  All rights reserved.");
#endif /* not lint */

#ifndef lint
#if 0
static char sccsid[] = "@(#)uniq.c      8.3 (Berkeley) 5/4/95";
#endif
__RCSID("$NetBSD: uniq.c,v 1.22 2019/04/23 17:35:10 christos Exp $");
#endif /* not lint */

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

static int cflag, dflag, uflag;
static int numchars, numfields, repeats;

static FILE *file(const char *, const char *);
static void show(FILE *, const char *);
static const char *skip(const char *, size_t *);
static void obsolete(char *[]);
static void usage(void) __dead;

int
main (int argc, char *argv[])
{
        const char *prevp, *thisp;
        FILE *ifp, *ofp;
        int ch;
        char *prevline, *thisline, *p;
        size_t prevlinesize, thislinesize, psize;
        size_t prevlen, thislen;

        setprogname(argv[0]);
        ifp = ofp = NULL;
        obsolete(argv);
        while ((ch = getopt(argc, argv, "cdf:s:u")) != -1)
                switch (ch) {
                case 'c':
                        cflag = 1;
                        break;
                case 'd':
                        dflag = 1;
                        break;
                case 'f':
                        numfields = strtol(optarg, &p, 10);
                        if (numfields < 0 || *p)
                                errx(1, "illegal field skip value: %s", optarg);
                        break;
                case 's':
                        numchars = strtol(optarg, &p, 10);
                        if (numchars < 0 || *p)
                                errx(1, "illegal character skip value: %s",
                                    optarg);
                        break;
                case 'u':
                        uflag = 1;
                        break;
                case '?':
                default:
                        usage();
        }

        argc -= optind;
        argv +=optind;

        switch(argc) {
        case 0:
                ifp = stdin;
                ofp = stdout;
                break;
        case 1:
                ifp = file(argv[0], "r");
                ofp = stdout;
                break;
        case 2:
                ifp = file(argv[0], "r");
                ofp = file(argv[1], "w");
                break;
        default:
                usage();
        }

        if ((p = fgetln(ifp, &psize)) == NULL)
                return 0;
        prevlinesize = prevlen = psize;
        if ((prevline = malloc(prevlinesize + 1)) == NULL)
                err(1, "malloc");
        (void)memcpy(prevline, p, prevlinesize);
        prevline[prevlinesize] = '\0';
        
        if (numfields || numchars)
                prevp = skip(prevline, &prevlen);
        else
                prevp = prevline;

        thislinesize = psize;
        if ((thisline = malloc(thislinesize + 1)) == NULL)
                err(1, "malloc");

        while ((p = fgetln(ifp, &psize)) != NULL) {
                if (psize > thislinesize) {
                        if ((thisline = realloc(thisline, psize + 1)) == NULL)
                                err(1, "realloc");
                        thislinesize = psize;
                }
                thislen = psize;
                (void)memcpy(thisline, p, psize);
                thisline[psize] = '\0';

                /* If requested get the chosen fields + character offsets. */
                if (numfields || numchars) {
                        thisp = skip(thisline, &thislen);
                } else {
                        thisp = thisline;
                }

                /* If different, print; set previous to new value. */
                if (thislen != prevlen || strcmp(thisp, prevp)) {
                        char *t;
                        size_t ts;

                        show(ofp, prevline);
                        t = prevline;
                        prevline = thisline;
                        thisline = t;
                        ts = prevlinesize;
                        prevlinesize = thislinesize;
                        thislinesize = ts;
                        prevp = thisp;
                        prevlen = thislen;
                        repeats = 0;
                } else
                        ++repeats;
        }
        show(ofp, prevline);
        free(prevline);
        free(thisline);
        return 0;
}

/*
 * show --
 *      Output a line depending on the flags and number of repetitions
 *      of the line.
 */
static void
show(FILE *ofp, const char *str)
{

        if ((dflag && repeats == 0) || (uflag && repeats > 0))
                return;
        if (cflag) {
                (void)fprintf(ofp, "%4d %s", repeats + 1, str);
        } else {
                (void)fprintf(ofp, "%s", str);
        }
}

static const char *
skip(const char *str, size_t *linesize)
{
        int infield, nchars, nfields;
        size_t ls = *linesize;

        for (nfields = numfields, infield = 0; nfields && *str; ++str, --ls)
                if (isspace((unsigned char)*str)) {
                        if (infield) {
                                infield = 0;
                                --nfields;
                        }
                } else if (!infield)
                        infield = 1;
        for (nchars = numchars; nchars-- && *str; ++str, --ls)
                continue;
        *linesize = ls;
        return str;
}

static FILE *
file(const char *name, const char *mode)
{
        FILE *fp;

        if ((fp = fopen(name, mode)) == NULL)
                err(1, "%s", name);
        return(fp);
}

static void
obsolete(char *argv[])
{
        char *ap, *p, *start;

        while ((ap = *++argv) != NULL) {
                /* Return if "--" or not an option of any form. */
                if (ap[0] != '-') {
                        if (ap[0] != '+')
                                return;
                } else if (ap[1] == '-')
                        return;
                if (!isdigit((unsigned char)ap[1]))
                        continue;
                /*
                 * Digit signifies an old-style option.  Malloc space for dash,
                 * new option and argument.
                 */
                (void)asprintf(&p, "-%c%s", ap[0] == '+' ? 's' : 'f', ap + 1);
                if (!p)
                        err(1, "malloc");
                start = p;
                *argv = start;
        }
}

static void
usage(void)
{
        (void)fprintf(stderr, "usage: %s [-cdu] [-f fields] [-s chars] "
            "[input_file [output_file]]\n", getprogname());
        exit(1);
}