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

enum Token {
	LINVALID,
	LEND,
	LRIGHT,
	LLEFT,
	LINC,
	LDEC,
	LOUT,
	LIN,
	LLOOP,
	LENDL,
};

enum Symbol {
	INVALID,
	END,
	RIGHT,
	LEFT,
	INC,
	DEC,
	OUT,
	IN,
	LOOP,
	ENDL,
};

typedef struct Sym Sym;

struct Sym {
	int inst;
	Sym *loop;
	Sym *next;
};

typedef struct Bf {
	int *i;  // instructions
	size_t in;  // instructions number
	size_t is;  // instructions size
	unsigned char *d;  // data
	int *ip;  // instruction pointer
	unsigned char *dp;  // data pointer
} Bf;

void *
emalloc(size_t s)
{
	void *p;

	p = malloc(s);
	if(!p){
		fprintf(stderr, "Error: Out of memory.\n");
		exit(EXIT_FAILURE);
	}
	return p;
}

void *
erealloc(void *p, size_t s)
{
	p = realloc(p, s);
	if(!p){
		fprintf(stderr, "Error: Out of memory.\n");
		exit(EXIT_FAILURE);
	}
	return p;
}

int
lex(FILE *f, size_t *l, size_t *b)
{
	int c;

	while((c = fgetc(f)) != EOF){
		switch(c){
		default:
			fprintf(stderr, "Error: Invalid character at line %zu column %zu: %c\n", *l, *b, c);
			exit(EXIT_FAILURE);
		case '>': return LRIGHT;
		case '<': return LLEFT;
		case '+': return LINC;
		case '-': return LDEC;
		case '.': return LOUT;
		case ',': return LIN;
		case '[': return LLOOP;
		case ']': return LENDL;
		case '\n':
			*l += 1;
			*b = 0;
			break;
		}
	}
	if(ferror(f)){
		fprintf(stderr, "Error: I/O error when reading file\n");
		exit(EXIT_FAILURE);
	}
	return LEND;
}

Sym *
parse(FILE *f)
{
	int t;
	size_t l, b;
	Sym **stk;
	size_t stkn, stks;
	Sym *h;
	Sym *n;
	Sym **p;

	l = 1;
	b = 1;

	stkn = 0;
	stks = sizeof(*stk);
	stk = emalloc(stks);

	for(p = &h; (t = lex(f, &l, &b)) != LEND;){
		*p = emalloc(sizeof(**p));
		n = *p;
		n->inst = INVALID;
		n->loop = 0;
		n->next = 0;
		switch(t){
		default:
			fprintf(stderr, "Error: Invalid token at line %zu column %zu: %d\n", l, b, t);
			exit(EXIT_FAILURE);
		case LRIGHT:
			n->inst = RIGHT;
			p = &n->next;
			break;
		case LLEFT:
			n->inst = LEFT;
			p = &n->next;
			break;
		case LINC:
			n->inst = LINC;
			p = &n->next;
			break;
		case LDEC:
			n->inst = LDEC;
			p = &n->next;
			break;
		case LOUT:
			n->inst = OUT;
			p = &n->next;
			break;
		case LIN:
			n->inst = IN;
			p = &n->next;
			break;
		case LLOOP:
			n->inst = LOOP;
			p = &n->loop;
			if(stkn >= stks){
				stk = erealloc(stk, 2 * stks);
			}
			stk[stkn++] = n;
			break;
		case LENDL:
			n->inst = ENDL;
			if(stkn <= 0){
				fprintf(stderr, "Error: Too many loop endings at line %zu column %zu.\n", l, b);
				exit(EXIT_FAILURE);
			}
			n = stk[--stkn];
			p = &n->next;
			break;
		}
	}
	if(stkn > 0){
		fprintf(stderr, "Error: Not enough loop endings.\n");
		exit(EXIT_FAILURE);
	}
	free(stk);

	return h;
}

void
emit()
{
}

void
run()
{
}

int
main(void)
{
	Sym *s;

	s = parse(stdin);
	printf("lol\n");
	return EXIT_SUCCESS;
}