Subversion Repositories planix.SVN

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

#define         BUF             65536

int sflag = 0;
int lflag = 0;
int Lflag = 0;

static void usage(void);

char **
seekoff(int fd, char *name, char **argv)
{
        vlong o;

        if(*argv){
                if (!isascii(**argv) || !isdigit(**argv))
                        usage();
                o = strtoll(*argv++, 0, 0);
                if(seek(fd, o, 0) < 0){
                        if(!sflag) fprint(2, "cmp: %s: seek by %lld: %r\n",
                                name, o);
                        exits("seek");
                }
        }
        return argv;
}

void
main(int argc, char *argv[])
{
        int n, i;
        uchar *p, *q;
        uchar buf1[BUF], buf2[BUF];
        int f1, f2;
        vlong nc = 1, l = 1;
        char *name1, *name2;
        uchar *b1s, *b1e, *b2s, *b2e;

        ARGBEGIN{
        case 's':       sflag = 1; break;
        case 'l':       lflag = 1; break;
        case 'L':       Lflag = 1; break;
        default:        usage();
        }ARGEND
        if(argc < 2 || argc > 4)
                usage();
        if((f1 = open(name1 = *argv++, OREAD)) == -1){
                if(!sflag) perror(name1);
                exits("open");
        }
        if((f2 = open(name2 = *argv++, OREAD)) == -1){
                if(!sflag) perror(name2);
                exits("open");
        }
        argv = seekoff(f1, name1, argv);
        argv = seekoff(f2, name2, argv);
        if(*argv)
                usage();

        b1s = b1e = buf1;
        b2s = b2e = buf2;
        for(;;){
                if(b1s >= b1e){
                        if(b1s >= &buf1[BUF])
                                b1s = buf1;
                        n = read(f1, b1s,  &buf1[BUF] - b1s);
                        b1e = b1s + n;
                }
                if(b2s >= b2e){
                        if(b2s >= &buf2[BUF])
                                b2s = buf2;
                        n = read(f2, b2s,  &buf2[BUF] - b2s);
                        b2e = b2s + n;
                }
                n = b2e - b2s;
                if(n > b1e - b1s)
                        n = b1e - b1s;
                if(n <= 0)
                        break;
                if(memcmp((void *)b1s, (void *)b2s, n) != 0){
                        if(sflag)
                                exits("differ");
                        for(p = b1s, q = b2s, i = 0; i < n; p++, q++, i++) {
                                if(*p == '\n')
                                        l++;
                                if(*p != *q){
                                        if(!lflag){
                                                print("%s %s differ: char %lld",
                                                    name1, name2, nc+i);
                                                print(Lflag?" line %lld\n":"\n", l);
                                                exits("differ");
                                        }
                                        print("%6lld 0x%.2x 0x%.2x\n", nc+i, *p, *q);
                                }
                        }
                }               
                if(Lflag)
                        for(p = b1s; p < b1e;)
                                if(*p++ == '\n')
                                        l++;
                nc += n;
                b1s += n;
                b2s += n;
        }
        if (b1e - b1s < 0 || b2e - b2s < 0) {
                if (!sflag) {
                        if (b1e - b1s < 0)
                                print("error on %s after %lld bytes\n",
                                        name1, nc-1);
                        if (b2e - b2s < 0)
                                print("error on %s after %lld bytes\n",
                                        name2, nc-1);
                }
                exits("read error");
        }
        if(b1e - b1s == b2e - b2s)
                exits((char *)0);
        if(!sflag)
                print("EOF on %s after %lld bytes\n",
                        (b1e - b1s > b2e - b2s)? name2 : name1, nc-1);
        exits("EOF");
}

static void
usage(void)
{
        print("usage: cmp [-lLs] file1 file2 [offset1 [offset2] ]\n");
        exits("usage");
}