//Put *s to stderr, print 20 chars of problem, exit(1)
int
error(char *s)
{
int i;
eputstr(s);
eputstr(" at: ");
i = 0;
while(i<20) {
eputchar(getchar());
i++;
}
eputstr("\n");
exit(1);
}
void main(int argc, char *argv[])
{
int fd1;
int fd2;
int cc1;
int cc2;
long pos;
char *bp1;
char *bp2;
struct stat statbuf1;
struct stat statbuf2;
if (argc < 3) {
eputstr(argv[0]);
eputstr(": file1 file2.\n");
exit(2);
}
if (stat(argv[1], &statbuf1) < 0) {
perror(argv[1]);
exit(2);
}
if (stat(argv[2], &statbuf2) < 0) {
perror(argv[2]);
exit(2);
}
if ((statbuf1.st_dev == statbuf2.st_dev) &&
(statbuf1.st_ino == statbuf2.st_ino))
{
putstr("Files are links to each other\n");
exit(0);
}
if (statbuf1.st_size != statbuf2.st_size) {
putstr("Files are different sizes\n");
exit(1);
}
fd1 = open(argv[1], 0);
if (fd1 < 0) {
perror(argv[1]);
exit(2);
}
fd2 = open(argv[2], 0);
if (fd2 < 0) {
perror(argv[2]);
close(fd1);
exit(2);
}
pos = 0;
while (1) {
cc1 = read(fd1, buf1, sizeof(buf1));
if (cc1 < 0) {
perror(argv[1]);
exit(2);
}
cc2 = read(fd2, buf2, sizeof(buf2));
if (cc2 < 0) {
perror(argv[2]);
goto differ;
}
if ((cc1 == 0) && (cc2 == 0)) {
putstr("Files are identical\n");
goto same;
}
if (cc1 < cc2) {
putstr("First file is shorter than second\n");
goto differ;
}
if (cc1 > cc2) {
putstr("Second file is shorter than first\n");
goto differ;
}
if (memcmp(buf1, buf2, cc1) == 0) {
pos += cc1;
continue;
}
bp1 = buf1;
bp2 = buf2;
while (*bp1++ == *bp2++)
pos++;
putstr("Files differ at byte position ");
bp1 = _ultoa(pos);
putstr(bp1);
putstr("\n");
goto differ;
}
same:
exit(0);
differ:
exit(1);
}
