9base

revived minimalist port of Plan 9 userland to Unix
git clone git://git.suckless.org/9base
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cmp.c (2098B)

      1 #include <u.h>
      2 #include <libc.h>
      3 
      4 #define		BUF		65536
      5 
      6 int sflag = 0;
      7 int lflag = 0;
      8 int Lflag = 0;
      9 
     10 static void usage(void);
     11 
     12 void
     13 main(int argc, char *argv[])
     14 {
     15 	int n, i;
     16 	uchar *p, *q;
     17 	uchar buf1[BUF], buf2[BUF];
     18 	int f1, f2;
     19 	vlong nc = 1, o, l = 1;
     20 	char *name1, *name2;
     21 	uchar *b1s, *b1e, *b2s, *b2e;
     22 
     23 	ARGBEGIN{
     24 	case 's':	sflag = 1; break;
     25 	case 'l':	lflag = 1; break;
     26 	case 'L':	Lflag = 1; break;
     27 	default:	usage();
     28 	}ARGEND
     29 	if(argc < 2)
     30 		usage();
     31 	if((f1 = open(name1 = *argv++, OREAD)) == -1){
     32 		if(!sflag) perror(name1);
     33 		exits("open");
     34 	}
     35 	if((f2 = open(name2 = *argv++, OREAD)) == -1){
     36 		if(!sflag) perror(name2);
     37 		exits("open");
     38 	}
     39 	if(*argv){
     40 		o = strtoll(*argv++, 0, 0);
     41 		if(seek(f1, o, 0) < 0){
     42 			if(!sflag) perror("cmp: seek by offset1");
     43 			exits("seek 1");
     44 		}
     45 	}
     46 	if(*argv){
     47 		o = strtoll(*argv++, 0, 0);
     48 		if(seek(f2, o, 0) < 0){
     49 			if(!sflag) perror("cmp: seek by offset2");
     50 			exits("seek 2");
     51 		}
     52 	}
     53 	if(*argv)
     54 		usage();
     55 	b1s = b1e = buf1;
     56 	b2s = b2e = buf2;
     57 	for(;;){
     58 		if(b1s >= b1e){
     59 			if(b1s >= &buf1[BUF])
     60 				b1s = buf1;
     61 			n = read(f1, b1s,  &buf1[BUF] - b1s);
     62 			b1e = b1s + n;
     63 		}
     64 		if(b2s >= b2e){
     65 			if(b2s >= &buf2[BUF])
     66 				b2s = buf2;
     67 			n = read(f2, b2s,  &buf2[BUF] - b2s);
     68 			b2e = b2s + n;
     69 		}
     70 		n = b2e - b2s;
     71 		if(n > b1e - b1s)
     72 			n = b1e - b1s;
     73 		if(n <= 0)
     74 			break;
     75 		if(memcmp((void *)b1s, (void *)b2s, n) != 0){
     76 			if(sflag)
     77 				exits("differ");
     78 			for(p = b1s, q = b2s, i = 0; i < n; p++, q++, i++) {
     79 				if(*p == '\n')
     80 					l++;
     81 				if(*p != *q){
     82 					if(!lflag){
     83 						print("%s %s differ: char %lld",
     84 						    name1, name2, nc+i);
     85 						print(Lflag?" line %lld\n":"\n", l);
     86 						exits("differ");
     87 					}
     88 					print("%6lld 0x%.2x 0x%.2x\n", nc+i, *p, *q);
     89 				}
     90 			}
     91 		}		
     92 		if(Lflag)
     93 			for(p = b1s; p < b1e;)
     94 				if(*p++ == '\n')
     95 					l++;
     96 		nc += n;
     97 		b1s += n;
     98 		b2s += n;
     99 	}
    100 	if(b1e - b1s == b2e - b2s)
    101 		exits((char *)0);
    102 	if(!sflag)
    103 		print("EOF on %s\n", (b1e - b1s > b2e - b2s)? name2 : name1);
    104 	exits("EOF");
    105 }
    106 
    107 static void
    108 usage(void)
    109 {
    110 	print("Usage: cmp [-lsL] file1 file2 [offset1 [offset2] ]\n");
    111 	exits("usage");
    112 }