1 #include <u.h>
2 #include <libc.h>
3 #include <ctype.h>
4
5 #define BUF 65536
6
7 int sflag = 0;
8 int lflag = 0;
9 int Lflag = 0;
10
11 static void usage(void);
12
13 char **
seekoff(int fd,char * name,char ** argv)14 seekoff(int fd, char *name, char **argv)
15 {
16 vlong o;
17
18 if(*argv){
19 if (!isascii(**argv) || !isdigit(**argv))
20 usage();
21 o = strtoll(*argv++, 0, 0);
22 if(seek(fd, o, 0) < 0){
23 if(!sflag) fprint(2, "cmp: %s: seek by %lld: %r\n",
24 name, o);
25 exits("seek");
26 }
27 }
28 return argv;
29 }
30
31 void
main(int argc,char * argv[])32 main(int argc, char *argv[])
33 {
34 int n, i;
35 uchar *p, *q;
36 uchar buf1[BUF], buf2[BUF];
37 int f1, f2;
38 vlong nc = 1, l = 1;
39 char *name1, *name2;
40 uchar *b1s, *b1e, *b2s, *b2e;
41
42 ARGBEGIN{
43 case 's': sflag = 1; break;
44 case 'l': lflag = 1; break;
45 case 'L': Lflag = 1; break;
46 default: usage();
47 }ARGEND
48 if(argc < 2 || argc > 4)
49 usage();
50 if((f1 = open(name1 = *argv++, OREAD)) == -1){
51 if(!sflag) perror(name1);
52 exits("open");
53 }
54 if((f2 = open(name2 = *argv++, OREAD)) == -1){
55 if(!sflag) perror(name2);
56 exits("open");
57 }
58 argv = seekoff(f1, name1, argv);
59 argv = seekoff(f2, name2, argv);
60 if(*argv)
61 usage();
62
63 b1s = b1e = buf1;
64 b2s = b2e = buf2;
65 for(;;){
66 if(b1s >= b1e){
67 if(b1s >= &buf1[BUF])
68 b1s = buf1;
69 n = read(f1, b1s, &buf1[BUF] - b1s);
70 b1e = b1s + n;
71 }
72 if(b2s >= b2e){
73 if(b2s >= &buf2[BUF])
74 b2s = buf2;
75 n = read(f2, b2s, &buf2[BUF] - b2s);
76 b2e = b2s + n;
77 }
78 n = b2e - b2s;
79 if(n > b1e - b1s)
80 n = b1e - b1s;
81 if(n <= 0)
82 break;
83 if(memcmp((void *)b1s, (void *)b2s, n) != 0){
84 if(sflag)
85 exits("differ");
86 for(p = b1s, q = b2s, i = 0; i < n; p++, q++, i++) {
87 if(*p == '\n')
88 l++;
89 if(*p != *q){
90 if(!lflag){
91 print("%s %s differ: char %lld",
92 name1, name2, nc+i);
93 print(Lflag?" line %lld\n":"\n", l);
94 exits("differ");
95 }
96 print("%6lld 0x%.2x 0x%.2x\n", nc+i, *p, *q);
97 }
98 }
99 }
100 if(Lflag)
101 for(p = b1s; p < b1e;)
102 if(*p++ == '\n')
103 l++;
104 nc += n;
105 b1s += n;
106 b2s += n;
107 }
108 if (b1e - b1s < 0 || b2e - b2s < 0) {
109 if (!sflag) {
110 if (b1e - b1s < 0)
111 print("error on %s after %lld bytes\n",
112 name1, nc-1);
113 if (b2e - b2s < 0)
114 print("error on %s after %lld bytes\n",
115 name2, nc-1);
116 }
117 exits("read error");
118 }
119 if(b1e - b1s == b2e - b2s)
120 exits((char *)0);
121 if(!sflag)
122 print("EOF on %s after %lld bytes\n",
123 (b1e - b1s > b2e - b2s)? name2 : name1, nc-1);
124 exits("EOF");
125 }
126
127 static void
usage(void)128 usage(void)
129 {
130 print("usage: cmp [-lLs] file1 file2 [offset1 [offset2] ]\n");
131 exits("usage");
132 }
133