adhock implementation of brainf*ck

brainf*ck

#include <stdio.h>
#include <stdlib.h>

#define INPUT_BUFSIZE 4096
#define HEAP_SIZE 65535

#define SYM_INC_PTR '>'
#define SYM_DEC_PTR '<'
#define SYM_ADD_CUR '+'
#define SYM_SUB_CUR '-'
#define SYM_OUTPUT '.'
#define SYM_INPUT ','
#define SYM_JZE '['
#define SYM_JNZ ']'


char *search_close_bracket(char *cur);
char *search_open_bracket(char *cur);

int main(int argc, char *argv[])
{
  char buf[INPUT_BUFSIZE];
  char heap[HEAP_SIZE];
  char *cur, *pointer;


  fgets(buf, INPUT_BUFSIZE, stdin);
  memset(heap, 0x00, HEAP_SIZE);
  
  cur = &buf[0];
  pointer = &heap[0];

  while(*cur != '\0') {

    switch(*cur) {
    case SYM_INC_PTR:
      pointer++; /* TODO: LIMIT CHECK */
      break;
      
    case SYM_DEC_PTR:
      pointer--; /* TODO: LIMIT CHECK */
      break;
      
    case SYM_ADD_CUR:
      *pointer += 1;
      break;

    case SYM_SUB_CUR:
      *pointer -= 1;
      break;
      
    case SYM_OUTPUT:
      fputc(*pointer, stdout);
      break;
      
    case SYM_INPUT:
      *pointer = fgetc(stdin);
      break;
      
    case SYM_JZE:
      if (*pointer == 0) {
        cur = search_close_bracket(cur) - 1;
      }
      break;

    case SYM_JNZ:
      if (*pointer != 0) {
        cur = search_open_bracket(cur);
      }
      break;

    case '\n':
    case '\r':
    case ' ':
    case '\t':
      /* ignore blank characters */
      break;

    default:
      fprintf(stderr, "unrecognized character - %c\n", *cur);
      
      return;
      break;
    }
    
    cur++;
  }
}

/* TODO: LIMIT CHECK */
char *search_close_bracket(char *cur)
{
  int level = 0;

  cur++;
  level++;

  while (level > 0) {
    if (*cur == '[') 
      level++;
    else if (*cur == ']')
      level--;
    cur++;
  }
  
  return cur;
}

/* TODO: LIMIT CHECK */
char *search_open_bracket(char *cur)
{
  int level = 0;
  
  cur--;
  level++;

  while (level > 0) {
    if (*cur == '[')
      level--;
    else if (*cur == ']')
      level++;
    cur--;
  }
  
  return cur;
}