#include <u.h>#include <libc.h> #define		BUF		65536 int sflag = 0;int lflag = 0;int Lflag = 0; static void usage(void); voidmain(int argc, char *argv[]){	int n, i;	uchar *p, *q;	uchar buf1[BUF], buf2[BUF];	int f1, f2;	vlong nc = 1, o, 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)		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");	}	if(*argv){		o = strtoll(*argv++, 0, 0);		if(seek(f1, o, 0) < 0){			if(!sflag) perror("cmp: seek by offset1");			exits("seek 1");		}	}	if(*argv){		o = strtoll(*argv++, 0, 0);		if(seek(f2, o, 0) < 0){			if(!sflag) perror("cmp: seek by offset2");			exits("seek 2");		}	}	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 == b2e - b2s)		exits((char *)0);	if(!sflag)		print("EOF on %s\n", (b1e - b1s > b2e - b2s)? name2 : name1);	exits("EOF");} static voidusage(void){	print("Usage: cmp [-lsL] file1 file2 [offset1 [offset2] ]\n");	exits("usage");}