BSD_LINE_MAX -> POSIX2_LINE_MAX

[unix-history] / usr / src / usr.bin / comm / comm.c

/*
* 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.
*
* %sccs.include.redist.c%
*/

#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      5.6 (Berkeley) %G%";
#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;
       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);
}