144 lines
3.4 KiB
C
144 lines
3.4 KiB
C
/*
|
|
* This program is free software. It comes without any warranty, to
|
|
* the extent permitted by applicable law. You can redistribute it
|
|
* and/or modify it under the terms of the Do What The Fuck You Want
|
|
* To Public License, Version 2, as published by Sam Hocevar. See
|
|
* http://www.wtfpl.net/ for more details.
|
|
*/
|
|
|
|
#include<stdio.h>
|
|
#include<stdint.h>
|
|
#include<stdlib.h>
|
|
#include<errno.h>
|
|
#include<assert.h>
|
|
#include<ctype.h>
|
|
|
|
// Amount of memory on the band tape
|
|
#define MEMORY_SIZE 10000
|
|
#define MAX_INPUT_SIZE 1000
|
|
|
|
// Memory initialized with zeros and its pointer
|
|
char memory[MEMORY_SIZE] = {0};
|
|
char *p = memory;
|
|
|
|
// Prototypes
|
|
void bfuck_parser(char *input);
|
|
|
|
// Error handler
|
|
void die(const char *message)
|
|
{
|
|
if(errno) {
|
|
perror(message);
|
|
} else {
|
|
printf("[:-(] Error: %s\n", message);
|
|
}
|
|
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
|
|
// Parses and executes a brainfuck expression
|
|
void bfuck_parser(char *input)
|
|
{
|
|
int loop = 0;
|
|
|
|
for(size_t i = 0; input[i] != 0; i++) { // where i is the instruction pointer
|
|
switch(input[i]) {
|
|
case '>':
|
|
++p; // increment data pointer
|
|
break;
|
|
|
|
case '<':
|
|
--p; // decrement data pointer
|
|
break;
|
|
|
|
case '+':
|
|
++(*p); // increment byte at data pointer
|
|
break;
|
|
|
|
case '-':
|
|
--(*p); // decrement byte at data pointer
|
|
break;
|
|
|
|
case '.':
|
|
putchar(*p); // output the byte at data pointer
|
|
break;
|
|
|
|
case ',':
|
|
*p = getchar(); // accept one byte of input and store it at data pointer
|
|
break;
|
|
|
|
case '[':
|
|
if(*p == 0) { // if the byte at the data pointer is zero
|
|
// jump forward to the command after the next ]
|
|
loop = 1;
|
|
// jump back to the command after the matching [
|
|
while(loop > 0) {
|
|
i++;
|
|
if(input[i] == '[') {
|
|
loop++;
|
|
}
|
|
if(input[i] == ']') {
|
|
loop--;
|
|
}
|
|
}
|
|
} else {
|
|
continue; // increment instruction pointer
|
|
}
|
|
break;
|
|
|
|
case ']':
|
|
if(*p != 0) { // if the byte at the data pointer is nonzero
|
|
loop = 1;
|
|
// jump back to the command after the matching [
|
|
while(loop > 0) {
|
|
i--;
|
|
if(input[i] == '[') {
|
|
loop--;
|
|
}
|
|
if(input[i] == ']') {
|
|
loop++;
|
|
}
|
|
}
|
|
|
|
} else {
|
|
continue; // increment instruction pointer
|
|
}
|
|
break;
|
|
|
|
default:
|
|
// Do nothing
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
int main(int argc, char* argv[])
|
|
{
|
|
FILE *fp;
|
|
int i = 0;
|
|
int c;
|
|
char input[MAX_INPUT_SIZE];
|
|
|
|
// check arguments
|
|
if(argc < 2) {
|
|
die("Need more arguments.");
|
|
}
|
|
|
|
// try to open file
|
|
if((fp = fopen(argv[1], "rt")) == NULL) {
|
|
die("Couldn't open file.");
|
|
}
|
|
|
|
// read the whole file and store it in the input buffer
|
|
while((c = getc(fp)) != EOF) {
|
|
input[i++] = c;
|
|
}
|
|
|
|
// try to interpret it
|
|
bfuck_parser(input);
|
|
|
|
// close and exit
|
|
fclose(fp);
|
|
exit(EXIT_SUCCESS);
|
|
}
|