Subversion Repositories planix.SVN

#include <u.h>
#include <libc.h>
#include <bio.h>

#define LB 2048
int     one;
int     two;
int     three;

char    *ldr[3];

Biobuf *ib1;
Biobuf *ib2;
Biobuf *openfil(char*);
int     rd(Biobuf*, char*);
void    wr(char*, int);
void    copy(Biobuf*, char*, int);
int     compare(char*, char*);

void
main(int argc, char *argv[])
{
        int l;
        char    lb1[LB],lb2[LB];

        ldr[0] = "";
        ldr[1] = "\t";
        ldr[2] = "\t\t";
        l = 1;
        ARGBEGIN{
        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:
                goto Usage;

        }ARGEND

        if(argc < 2) {
    Usage:
                fprint(2, "usage: comm [-123] file1 file2\n");
                exits("usage");
        }

        ib1 = openfil(argv[0]);
        ib2 = openfil(argv[1]);


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

        for(;;){
                switch(compare(lb1,lb2)) {
                case 0:
                        wr(lb1,3);
                        if(rd(ib1,lb1) < 0) {
                                if(rd(ib2,lb2) < 0)
                                        exits(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;
                }
        }
}

int
rd(Biobuf *file, char *buf)
{
        int i, c;

        i = 0;
        while((c = Bgetc(file)) != Beof) {
                *buf = c;
                if(c == '\n' || i > LB-2) {
                        *buf = '\0';
                        return 0;
                }
                i++;
                buf++;
        }
        return -1;
}

void
wr(char *str, int n)
{

        switch(n){
                case 1:
                        if(one)
                                return;
                        break;

                case 2:
                        if(two)
                                return;
                        break;

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

void
copy(Biobuf *ibuf, char *lbuf, int n)
{
        do
                wr(lbuf,n);
        while(rd(ibuf,lbuf) >= 0);
        exits(0);
}

int
compare(char *a, char *b)
{
        while(*a == *b){
                if(*a == '\0')
                        return 0;
                a++;
                b++;
        }
        if(*a < *b)
                return 1;
        return 2;
}

Biobuf*
openfil(char *s)
{
        Biobuf *b;

        if(s[0]=='-' && s[1]==0)
                s = "/fd/0";
        b = Bopen(s, OREAD);
        if(b)
                return b;
        fprint(2,"comm: cannot open %s: %r\n",s);
        exits("open");
        return 0;       /* shut up ken */
}