sys/src/cmd/comm.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <bio.h>
   4
   5 #define LB 2048
   6 int     one;
   7 int     two;
   8 int     three;
   9
  10 char    *ldr[3];
  11
  12 Biobuf *ib1;
  13 Biobuf *ib2;
  14 Biobuf *openfil(char*);
  15 int     rd(Biobuf*, char*);
  16 void    wr(char*, int);
  17 void    copy(Biobuf*, char*, int);
  18 int     compare(char*, char*);
  19
  20 void
  21 main(int argc, char *argv[])
  22 {
  23         int l;
  24         char    lb1[LB],lb2[LB];
  25
  26         ldr[0] = "";
  27         ldr[1] = "\t";
  28         ldr[2] = "\t\t";
  29         l = 1;
  30         ARGBEGIN{
  31         case '1':
  32                 if(!one) {
  33                         one = 1;
  34                         ldr[1][0] =
  35                         ldr[2][l--] = '\0';
  36                 }
  37                 break;
  38
  39         case '2':
  40                 if(!two) {
  41                         two = 1;
  42                         ldr[2][l--] = '\0';
  43                 }
  44                 break;
  45
  46         case '3':
  47                 three = 1;
  48                 break;
  49
  50         default:
  51                 goto Usage;
  52
  53         }ARGEND
  54
  55         if(argc < 2) {
  56     Usage:
  57                 fprint(2, "usage: comm [-123] file1 file2\n");
  58                 exits("usage");
  59         }
  60
  61         ib1 = openfil(argv[0]);
  62         ib2 = openfil(argv[1]);
  63
  64
  65         if(rd(ib1,lb1) < 0){
  66                 if(rd(ib2,lb2) < 0)
  67                         exits(0);
  68                 copy(ib2,lb2,2);
  69         }
  70         if(rd(ib2,lb2) < 0)
  71                 copy(ib1,lb1,1);
  72
  73         for(;;){
  74                 switch(compare(lb1,lb2)) {
  75                 case 0:
  76                         wr(lb1,3);
  77                         if(rd(ib1,lb1) < 0) {
  78                                 if(rd(ib2,lb2) < 0)
  79                                         exits(0);
  80                                 copy(ib2,lb2,2);
  81                         }
  82                         if(rd(ib2,lb2) < 0)
  83                                 copy(ib1,lb1,1);
  84                         continue;
  85
  86                 case 1:
  87                         wr(lb1,1);
  88                         if(rd(ib1,lb1) < 0)
  89                                 copy(ib2,lb2,2);
  90                         continue;
  91
  92                 case 2:
  93                         wr(lb2,2);
  94                         if(rd(ib2,lb2) < 0)
  95                                 copy(ib1,lb1,1);
  96                         continue;
  97                 }
  98         }
  99 }
 100
 101 int
 102 rd(Biobuf *file, char *buf)
 103 {
 104         int i, c;
 105
 106         i = 0;
 107         while((c = Bgetc(file)) != Beof) {
 108                 *buf = c;
 109                 if(c == '\n' || i > LB-2) {
 110                         *buf = '\0';
 111                         return 0;
 112                 }
 113                 i++;
 114                 buf++;
 115         }
 116         return -1;
 117 }
 118
 119 void
 120 wr(char *str, int n)
 121 {
 122
 123         switch(n){
 124                 case 1:
 125                         if(one)
 126                                 return;
 127                         break;
 128
 129                 case 2:
 130                         if(two)
 131                                 return;
 132                         break;
 133
 134                 case 3:
 135                         if(three)
 136                                 return;
 137         }
 138         print("%s%s\n", ldr[n-1],str);
 139 }
 140
 141 void
 142 copy(Biobuf *ibuf, char *lbuf, int n)
 143 {
 144         do
 145                 wr(lbuf,n);
 146         while(rd(ibuf,lbuf) >= 0);
 147         exits(0);
 148 }
 149
 150 int
 151 compare(char *a, char *b)
 152 {
 153         while(*a == *b){
 154                 if(*a == '\0')
 155                         return 0;
 156                 a++;
 157                 b++;
 158         }
 159         if(*a < *b)
 160                 return 1;
 161         return 2;
 162 }
 163
 164 Biobuf*
 165 openfil(char *s)
 166 {
 167         Biobuf *b;
 168
 169         if(s[0]=='-' && s[1]==0)
 170                 s = "/fd/0";
 171         b = Bopen(s, OREAD);
 172         if(b)
 173                 return b;
 174         fprint(2,"comm: cannot open %s: %r\n",s);
 175         exits("open");
 176         return 0;       /* shut up ken */
 177 }