sys/src/cmd/cmp.c

   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 **
  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
  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
 128 usage(void)
 129 {
 130         print("usage: cmp [-lLs] file1 file2 [offset1 [offset2] ]\n");
 131         exits("usage");
 132 }