bfll.c

   1 #include <stdlib.h>
   2 #include <string.h>
   3 #include <stdio.h>
   4 #include <errno.h>
   5
   6 #define die(s, as...) {fprintf(stderr, s, ## as); return EXIT_FAILURE;}
   7 #define check_fail(v, s, f) if((v) == f) die("%s(): %s\n", s, strerror(errno))
   8 #define check_null(v, s) check_fail(v, s, NULL)
   9
  10 #define INITIALBUFSIZE 2
  11
  12 struct buf {
  13         char v;
  14         struct buf *n, *p;
  15 };
  16
  17 struct cs {
  18         long pl;
  19         struct cs *next;
  20 };
  21
  22 int main(int argc, char *argv[])
  23 {
  24         size_t depth;
  25         struct buf *p;
  26         struct cs *temp, *cs;
  27         FILE *in;
  28
  29         if(argc != 2)
  30                 die("Usage: %s PROGRAM\n", argv[0]);
  31
  32         check_null(in = fopen(argv[1], "r"), "fopen");
  33         check_null(p = calloc(sizeof (struct buf), 1), "calloc");
  34
  35         while (1){
  36                 switch (fgetc(in)){
  37                 case EOF:
  38                         check_fail(fclose(in), "fclose", -1);
  39                         while(p->p != NULL)
  40                                 p = p->p;
  41                         while(p->n != NULL)
  42                                 free((p = p->n)->p);
  43                         free(p);
  44                         return EXIT_SUCCESS;
  45                 case '>':
  46                         if(p->n == NULL){
  47                                 check_null(p->n = calloc(
  48                                         sizeof (struct buf), 1), "calloc");
  49                                 p->n->p = p;
  50                         }
  51                         p = p->n;
  52                         break;
  53                 case '<':
  54                         if(p->p == NULL){
  55                                 check_null(p->p = calloc(
  56                                         sizeof (struct buf), 1), "calloc");
  57                                 p->p->n = p;
  58                         }
  59                         p = p->p;
  60                         break;
  61                 case '+':
  62                         ++(p->v);
  63                         break;
  64                 case '-':
  65                         --(p->v);
  66                         break;
  67                 case '.':
  68                         putchar(p->v);
  69                         break;
  70                 case ',':
  71                         p->v = getchar();
  72                         break;
  73                 case '[':
  74                         if (p->v){
  75                                 temp = cs;
  76                                 check_null(cs = malloc(
  77                                         sizeof(struct cs)), "malloc");
  78                                 cs->next = temp;
  79                                 check_fail(cs->pl = ftell(in), "ftell", -1);
  80                         } else {
  81                                 depth = 1;
  82                                 while (depth > 0){
  83                                         switch (fgetc(in)){
  84                                         case ']':
  85                                                 depth--;
  86                                                 break;
  87                                         case '[':
  88                                                 depth++;
  89                                         }
  90                                 }
  91                         }
  92                         break;
  93                 case ']':
  94                         check_fail(fseek(in, cs->pl-1, SEEK_SET), "fseek", -1);
  95                         temp = cs;
  96                         cs = cs->next;
  97                         free(temp);
  98                 }
  99         }
 100 }