date and time created 80/10/01 17:25:50 by bill

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

static char *sccsid = "@(#)comm.c       4.1 (Berkeley) %G%";
#include <stdio.h>
#define LB 256
int     one;
int     two;
int     three;

char    *ldr[3];

FILE *ib1;
FILE *ib2;
FILE *openfil();
main(argc,argv)
char    *argv[];
{
       int     l;
       char    lb1[LB],lb2[LB];

       ldr[0] = "";
       ldr[1] = "\t";
       ldr[2] = "\t\t";
       if(argc > 1)  {
               if(*argv[1] == '-' && argv[1][1] != 0) {
                       l = 1;
                       while(*++argv[1]) {
                               switch(*argv[1]) {
                               case'1':
                                       if(!one) {
                                               one = 1;
                                               ldr[1][0] =
                                               ldr[2][l--] = '\0';
                                       }
                                       break;
                               case '2':
                                       if(!two) {
                                               two = 1;
                                               ldr[2][l--] = '\0';
                                       }
                                       break;
                               case '3':
                                       three = 1;
                                       break;
                               default:
                               fprintf(stderr,"comm: illegal flag\n");
                               exit(1);
                               }
                       }
                       argv++;
                       argc--;
               }
       }

       if(argc < 3) {
               fprintf(stderr,"comm: arg count\n");
               exit(1);
       }

       ib1 = openfil(argv[1]);
       ib2 = openfil(argv[2]);


       if(rd(ib1,lb1) < 0) {
               if(rd(ib2,lb2) < 0)     exit(0);
               copy(ib2,lb2,2);
       }
       if(rd(ib2,lb2) < 0)     copy(ib1,lb1,1);

       while(1) {

               switch(compare(lb1,lb2)) {

                       case 0:
                               wr(lb1,3);
                               if(rd(ib1,lb1) < 0) {
                                       if(rd(ib2,lb2) < 0)     exit(0);
                                       copy(ib2,lb2,2);
                               }
                               if(rd(ib2,lb2) < 0)     copy(ib1,lb1,1);
                               continue;

                       case 1:
                               wr(lb1,1);
                               if(rd(ib1,lb1) < 0)     copy(ib2,lb2,2);
                               continue;

                       case 2:
                               wr(lb2,2);
                               if(rd(ib2,lb2) < 0)     copy(ib1,lb1,1);
                               continue;
               }
       }
}

rd(file,buf)
FILE *file;
char *buf;
{

       register int i, c;
       i = 0;
       while((c = getc(file)) != EOF) {
               *buf = c;
               if(c == '\n' || i > LB-2) {
                       *buf = '\0';
                       return(0);
               }
               i++;
               buf++;
       }
       return(-1);
}

wr(str,n)
       char    *str;
{

       switch(n) {

               case 1:
                       if(one) return;
                       break;

               case 2:
                       if(two) return;
                       break;

               case 3:
                       if(three)       return;
       }
       printf("%s%s\n",ldr[n-1],str);
}

copy(ibuf,lbuf,n)
FILE *ibuf;
char *lbuf;
{
       do {
               wr(lbuf,n);
       } while(rd(ibuf,lbuf) >= 0);

       exit(0);
}

compare(a,b)
       char    *a,*b;
{
       register char *ra,*rb;

       ra = --a;
       rb = --b;
       while(*++ra == *++rb)
               if(*ra == '\0') return(0);
       if(*ra < *rb)   return(1);
       return(2);
}
FILE *openfil(s)
char *s;
{
       FILE *b;
       if(s[0]=='-' && s[1]==0)
               b = stdin;
       else if((b=fopen(s,"r")) == NULL) {
               fprintf(stderr,"comm: cannot open %s\n",s);
               exit(1);
       }
       return(b);
}