InfoMagic Source Code 1993 July/THE_SOURCE_CODE_CD_ROM.iso/bsd_srcs/usr.bin/comm/comm.c

C/C++ Source or Header | 1991-04-17 | 4.3 KB | 176 lines

/*
 * Copyright (c) 1989 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
char copyright[] =
"@(#) Copyright (c) 1989 The Regents of the University of California.\n\
 All rights reserved.\n";
#endif /* not lint */

#ifndef lint
static char sccsid[] = "@(#)comm.c    5.7 (Berkeley) 11/1/90";
#endif /* not lint */

#include <sys/file.h>
#include <limits.h>
#include <stdio.h>

#define    MAXLINELEN    (_POSIX2_LINE_MAX + 1)

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

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

    flag1 = flag2 = flag3 = 1;
    while ((ch = getopt(argc, argv, "-123")) != EOF)
        switch(ch) {
        case '-':
            --optind;
            goto done;
        case '1':
            flag1 = 0;
            break;
        case '2':
            flag2 = 0;
            break;
        case '3':
            flag3 = 0;
            break;
        case '?':
        default:
            usage();
        }
done:    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 (!(comp = strcmp(line1, line2))) {
            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);
}

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

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

    if (!strcmp(name, "-"))
        return(stdin);
    if (!(fp = fopen(name, "r"))) {
        (void)fprintf(stderr, "comm: can't read %s.\n", name);
        exit(1);
    }
    return(fp);
}

usage()
{
    (void)fprintf(stderr, "usage: comm [-123] [ - ] file1 file2\n");
    exit(1);
}