cmp.c - 9base - revived minimalist port of Plan 9 userland to Unix
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cmp.c (2098B)
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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 }