/*
 * Copyright (c) 1989, 1993, 1994
 *      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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. 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.
 */

#ifndef lint
static const char copyright[] = "@(#) Copyright (c) 1989, 1993, 1994\n  The Regents of the University of California.  All rights reserved.\n";
#endif

#if 1
#ifndef lint
static char sccsid[] = "From: @(#)comm.c        8.4 (Berkeley) 5/4/95";
#endif
#endif

//#include <cdefs.h>
//__FBSDID("$FreeBSD: /repoman/r/ncvs/src/usr.bin/comm/comm.c,v 1.20 2002/07/28 15:28:38 dwmalone Exp $");

#include <ctype.h>
//#include <err.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#define LINE_MAX 99999
#define MAXLINELEN      (LINE_MAX + 1)

const char *tabs[] = { "", "\t", "\t\t" };

FILE   *file(const char *);
void    show(FILE *, const char *, char *);
int     stricoll(const char *, const char *);
static void     usage(void);
static void printversion(void);

int
main(int argc, char *argv[])
{
        int comp, file1done = 0, file2done = 0, read1, read2;
        int ch, flag1, flag2, flag3, iflag;
        FILE *fp1, *fp2;
        const char *col1, *col2, *col3;
        char line1[MAXLINELEN], line2[MAXLINELEN];
        const char **p;

        flag1 = flag2 = flag3 = 1;
        iflag = 0;

        (void) setlocale(LC_ALL, "");

        while ((ch = getopt(argc, argv, "123ivh")) != -1)
                switch(ch) {
                case '1':
                        flag1 = 0;
                        break;
                case '2':
                        flag2 = 0;
                        break;
                case '3':
                        flag3 = 0;
                        break;
                case 'i':
                        iflag = 1;
                        break;
                case 'v':
                        printversion();
                        break;
                default:
                        usage();
                }
                
        argc -= optind;
        argv += optind;

        if (argc != 2)
                usage();

        fp1 = file(argv[0]);
        fp2 = file(argv[1]);

        /* for each column printed, add another tab offset */
        p = tabs;
        col1 = col2 = col3 = NULL;
        if (flag1)
                col1 = *p++;
        if (flag2)
                col2 = *p++;
        if (flag3)
                col3 = *p;

        for (read1 = read2 = 1;;) {
                /* read next line, check for EOF */
                if (read1)
                        file1done = !fgets(line1, MAXLINELEN, fp1);
                if (read2)
                        file2done = !fgets(line2, MAXLINELEN, fp2);

                /* if one file done, display the rest of the other file */
                if (file1done) {
                        if (!file2done && col2)
                                show(fp2, col2, line2);
                        break;
                }
                if (file2done) {
                        if (!file1done && col1)
                                show(fp1, col1, line1);
                        break;
                }

                /* lines are the same */
                if(iflag)
                        comp = stricoll(line1, line2);
                else
                        comp = strcoll(line1, line2);

                if (!comp) {
                        read1 = read2 = 1;
                        if (col3)
                                (void)printf("%s%s", col3, line1);
                        continue;
                }

                /* lines are different */
                if (comp < 0) {
                        read1 = 1;
                        read2 = 0;
                        if (col1)
                                (void)printf("%s%s", col1, line1);
                } else {
                        read1 = 0;
                        read2 = 1;
                        if (col2)
                                (void)printf("%s%s", col2, line2);
                }
        }
        exit(0);
}

void
show(FILE *fp, const char *offset, char *buf)
{

        do {
                (void)printf("%s%s", offset, buf);
        } while (fgets(buf, MAXLINELEN, fp));
}

FILE *
file(const char *name)
{
        FILE *fp;

        if (!strcmp(name, "-"))
                return (stdin);
        if ((fp = fopen(name, "r")) == NULL) {
                sprintf("%s", name);
        }
        return (fp);
}

static void
usage(void)
{
        (void)fprintf(stderr, "Usage: /bin/comm [OPTION]... LEFT_FILE RIGHT_FILE
Compare sorted files LEFT_FILE and RIGHT_FILE line by line.

  -1              suppress lines unique to left file
  -2              suppress lines unique to right file
  -3              suppress lines unique to both files
  -help           display this help and exit
  -version        output version information and exit
 ");
        exit(1);
}

static void
printversion(void)
{
        (void)fprintf(stderr, copyright);
        (void)fprintf(stderr, "\nVersion : %s\n", sccsid);
        exit(1);
}

int
stricoll(const char *s1, const char *s2)
{
        char *p, line1[MAXLINELEN], line2[MAXLINELEN];

        for (p = line1; *s1; s1++)
                *p++ = tolower((unsigned char)*s1);
        *p = '\0';
        for (p = line2; *s2; s2++)
                *p++ = tolower((unsigned char)*s2);
        *p = '\0';
        return strcoll(line1, line2);
}