expr.c

用于生成linux操作系统下的交叉编译工具链和嵌入式linux系统的根文件系统,支持x86、arm、powerpc等处理器

		if (tmp) {
			expr_free(e1); expr_free(e2);
			e1 = expr_alloc_symbol(&symbol_yes);
			e2 = tmp;
			trans_count++;
		}
		break;
	default:
		;
	}
#undef e1
#undef e2
}

static void expr_eliminate_dups2(enum expr_type type, struct expr **ep1, struct expr **ep2)
{
#define e1 (*ep1)
#define e2 (*ep2)
	struct expr *tmp, *tmp1, *tmp2;

	if (e1->type == type) {
		expr_eliminate_dups2(type, &e1->left.expr, &e2);
		expr_eliminate_dups2(type, &e1->right.expr, &e2);
		return;
	}
	if (e2->type == type) {
		expr_eliminate_dups2(type, &e1, &e2->left.expr);
		expr_eliminate_dups2(type, &e1, &e2->right.expr);
	}
	if (e1 == e2)
		return;

	switch (e1->type) {
	case E_OR:
		expr_eliminate_dups2(e1->type, &e1, &e1);
		// (FOO || BAR) && (!FOO && !BAR) -> n
		tmp1 = expr_transform(expr_alloc_one(E_NOT, expr_copy(e1)));
		tmp2 = expr_copy(e2);
		tmp = expr_extract_eq_and(&tmp1, &tmp2);
		if (expr_is_yes(tmp1)) {
			expr_free(e1);
			e1 = expr_alloc_symbol(&symbol_no);
			trans_count++;
		}
		expr_free(tmp2);
		expr_free(tmp1);
		expr_free(tmp);
		break;
	case E_AND:
		expr_eliminate_dups2(e1->type, &e1, &e1);
		// (FOO && BAR) || (!FOO || !BAR) -> y
		tmp1 = expr_transform(expr_alloc_one(E_NOT, expr_copy(e1)));
		tmp2 = expr_copy(e2);
		tmp = expr_extract_eq_or(&tmp1, &tmp2);
		if (expr_is_no(tmp1)) {
			expr_free(e1);
			e1 = expr_alloc_symbol(&symbol_yes);
			trans_count++;
		}
		expr_free(tmp2);
		expr_free(tmp1);
		expr_free(tmp);
		break;
	default:
		;
	}
#undef e1
#undef e2
}

struct expr *expr_eliminate_dups(struct expr *e)
{
	int oldcount;
	if (!e)
		return e;

	oldcount = trans_count;
	while (1) {
		trans_count = 0;
		switch (e->type) {
		case E_OR: case E_AND:
			expr_eliminate_dups1(e->type, &e, &e);
			expr_eliminate_dups2(e->type, &e, &e);
		default:
			;
		}
		if (!trans_count)
			break;
		e = expr_eliminate_yn(e);
	}
	trans_count = oldcount;
	return e;
}

struct expr *expr_transform(struct expr *e)
{
	struct expr *tmp;

	if (!e)
		return NULL;
	switch (e->type) {
	case E_EQUAL:
	case E_UNEQUAL:
	case E_SYMBOL:
	case E_CHOICE:
		break;
	default:
		e->left.expr = expr_transform(e->left.expr);
		e->right.expr = expr_transform(e->right.expr);
	}

	switch (e->type) {
	case E_EQUAL:
		if (e->left.sym->type != S_BOOLEAN)
			break;
		if (e->right.sym == &symbol_no) {
			e->type = E_NOT;
			e->left.expr = expr_alloc_symbol(e->left.sym);
			e->right.sym = NULL;
			break;
		}
		if (e->right.sym == &symbol_mod) {
			printf("boolean symbol %s tested for 'm'? test forced to 'n'\n", e->left.sym->name);
			e->type = E_SYMBOL;
			e->left.sym = &symbol_no;
			e->right.sym = NULL;
			break;
		}
		if (e->right.sym == &symbol_yes) {
			e->type = E_SYMBOL;
			e->right.sym = NULL;
			break;
		}
		break;
	case E_UNEQUAL:
		if (e->left.sym->type != S_BOOLEAN)
			break;
		if (e->right.sym == &symbol_no) {
			e->type = E_SYMBOL;
			e->right.sym = NULL;
			break;
		}
		if (e->right.sym == &symbol_mod) {
			printf("boolean symbol %s tested for 'm'? test forced to 'y'\n", e->left.sym->name);
			e->type = E_SYMBOL;
			e->left.sym = &symbol_yes;
			e->right.sym = NULL;
			break;
		}
		if (e->right.sym == &symbol_yes) {
			e->type = E_NOT;
			e->left.expr = expr_alloc_symbol(e->left.sym);
			e->right.sym = NULL;
			break;
		}
		break;
	case E_NOT:
		switch (e->left.expr->type) {
		case E_NOT:
			// !!a -> a
			tmp = e->left.expr->left.expr;
			free(e->left.expr);
			free(e);
			e = tmp;
			e = expr_transform(e);
			break;
		case E_EQUAL:
		case E_UNEQUAL:
			// !a='x' -> a!='x'
			tmp = e->left.expr;
			free(e);
			e = tmp;
			e->type = e->type == E_EQUAL ? E_UNEQUAL : E_EQUAL;
			break;
		case E_OR:
			// !(a || b) -> !a && !b
			tmp = e->left.expr;
			e->type = E_AND;
			e->right.expr = expr_alloc_one(E_NOT, tmp->right.expr);
			tmp->type = E_NOT;
			tmp->right.expr = NULL;
			e = expr_transform(e);
			break;
		case E_AND:
			// !(a && b) -> !a || !b
			tmp = e->left.expr;
			e->type = E_OR;
			e->right.expr = expr_alloc_one(E_NOT, tmp->right.expr);
			tmp->type = E_NOT;
			tmp->right.expr = NULL;
			e = expr_transform(e);
			break;
		case E_SYMBOL:
			if (e->left.expr->left.sym == &symbol_yes) {
				// !'y' -> 'n'
				tmp = e->left.expr;
				free(e);
				e = tmp;
				e->type = E_SYMBOL;
				e->left.sym = &symbol_no;
				break;
			}
			if (e->left.expr->left.sym == &symbol_mod) {
				// !'m' -> 'm'
				tmp = e->left.expr;
				free(e);
				e = tmp;
				e->type = E_SYMBOL;
				e->left.sym = &symbol_mod;
				break;
			}
			if (e->left.expr->left.sym == &symbol_no) {
				// !'n' -> 'y'
				tmp = e->left.expr;
				free(e);
				e = tmp;
				e->type = E_SYMBOL;
				e->left.sym = &symbol_yes;
				break;
			}
			break;
		default:
			;
		}
		break;
	default:
		;
	}
	return e;
}

int expr_contains_symbol(struct expr *dep, struct symbol *sym)
{
	if (!dep)
		return 0;

	switch (dep->type) {
	case E_AND:
	case E_OR:
		return expr_contains_symbol(dep->left.expr, sym) ||
		       expr_contains_symbol(dep->right.expr, sym);
	case E_SYMBOL:
		return dep->left.sym == sym;
	case E_EQUAL:
	case E_UNEQUAL:
		return dep->left.sym == sym ||
		       dep->right.sym == sym;
	case E_NOT:
		return expr_contains_symbol(dep->left.expr, sym);
	default:
		;
	}
	return 0;
}

bool expr_depends_symbol(struct expr *dep, struct symbol *sym)
{
	if (!dep)
		return false;

	switch (dep->type) {
	case E_AND:
		return expr_depends_symbol(dep->left.expr, sym) ||
		       expr_depends_symbol(dep->right.expr, sym);
	case E_SYMBOL:
		return dep->left.sym == sym;
	case E_EQUAL:
		if (dep->left.sym == sym) {
			if (dep->right.sym == &symbol_yes || dep->right.sym == &symbol_mod)
				return true;
		}
		break;
	case E_UNEQUAL:
		if (dep->left.sym == sym) {
			if (dep->right.sym == &symbol_no)
				return true;
		}
		break;
	default:
		;
	}
 	return false;
}

struct expr *expr_extract_eq_and(struct expr **ep1, struct expr **ep2)
{
	struct expr *tmp = NULL;
	expr_extract_eq(E_AND, &tmp, ep1, ep2);
	if (tmp) {
		*ep1 = expr_eliminate_yn(*ep1);
		*ep2 = expr_eliminate_yn(*ep2);
	}
	return tmp;
}

struct expr *expr_extract_eq_or(struct expr **ep1, struct expr **ep2)
{
	struct expr *tmp = NULL;
	expr_extract_eq(E_OR, &tmp, ep1, ep2);
	if (tmp) {
		*ep1 = expr_eliminate_yn(*ep1);
		*ep2 = expr_eliminate_yn(*ep2);
	}
	return tmp;
}

void expr_extract_eq(enum expr_type type, struct expr **ep, struct expr **ep1, struct expr **ep2)
{
#define e1 (*ep1)
#define e2 (*ep2)
	if (e1->type == type) {
		expr_extract_eq(type, ep, &e1->left.expr, &e2);
		expr_extract_eq(type, ep, &e1->right.expr, &e2);
		return;
	}
	if (e2->type == type) {
		expr_extract_eq(type, ep, ep1, &e2->left.expr);
		expr_extract_eq(type, ep, ep1, &e2->right.expr);
		return;
	}
	if (expr_eq(e1, e2)) {
		*ep = *ep ? expr_alloc_two(type, *ep, e1) : e1;
		expr_free(e2);
		if (type == E_AND) {
			e1 = expr_alloc_symbol(&symbol_yes);
			e2 = expr_alloc_symbol(&symbol_yes);
		} else if (type == E_OR) {
			e1 = expr_alloc_symbol(&symbol_no);
			e2 = expr_alloc_symbol(&symbol_no);
		}
	}
#undef e1
#undef e2
}

struct expr *expr_trans_compare(struct expr *e, enum expr_type type, struct symbol *sym)
{
	struct expr *e1, *e2;

	if (!e) {
		e = expr_alloc_symbol(sym);
		if (type == E_UNEQUAL)
			e = expr_alloc_one(E_NOT, e);
		return e;
	}
	switch (e->type) {
	case E_AND:
		e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
		e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
		if (sym == &symbol_yes)
			e = expr_alloc_two(E_AND, e1, e2);
		if (sym == &symbol_no)
			e = expr_alloc_two(E_OR, e1, e2);
		if (type == E_UNEQUAL)
			e = expr_alloc_one(E_NOT, e);
		return e;
	case E_OR:
		e1 = expr_trans_compare(e->left.expr, E_EQUAL, sym);
		e2 = expr_trans_compare(e->right.expr, E_EQUAL, sym);
		if (sym == &symbol_yes)
			e = expr_alloc_two(E_OR, e1, e2);
		if (sym == &symbol_no)
			e = expr_alloc_two(E_AND, e1, e2);
		if (type == E_UNEQUAL)
			e = expr_alloc_one(E_NOT, e);
		return e;
	case E_NOT:
		return expr_trans_compare(e->left.expr, type == E_EQUAL ? E_UNEQUAL : E_EQUAL, sym);
	case E_UNEQUAL:
	case E_EQUAL:
		if (type == E_EQUAL) {
			if (sym == &symbol_yes)
				return expr_copy(e);
			if (sym == &symbol_mod)
				return expr_alloc_symbol(&symbol_no);
			if (sym == &symbol_no)
				return expr_alloc_one(E_NOT, expr_copy(e));
		} else {
			if (sym == &symbol_yes)
				return expr_alloc_one(E_NOT, expr_copy(e));
			if (sym == &symbol_mod)
				return expr_alloc_symbol(&symbol_yes);
			if (sym == &symbol_no)
				return expr_copy(e);
		}
		break;
	case E_SYMBOL:
		return expr_alloc_comp(type, e->left.sym, sym);
	case E_CHOICE:
	case E_RANGE:
	case E_NONE:
		/* panic */;
	}
	return NULL;
}

tristate expr_calc_value(struct expr *e)
{
	tristate val1, val2;
	const char *str1, *str2;

	if (!e)
		return yes;

	switch (e->type) {
	case E_SYMBOL:
		sym_calc_value(e->left.sym);
		return e->left.sym->curr.tri;
	case E_AND:
		val1 = expr_calc_value(e->left.expr);
		val2 = expr_calc_value(e->right.expr);
		return E_AND(val1, val2);
	case E_OR:
		val1 = expr_calc_value(e->left.expr);
		val2 = expr_calc_value(e->right.expr);
		return E_OR(val1, val2);
	case E_NOT:
		val1 = expr_calc_value(e->left.expr);
		return E_NOT(val1);
	case E_EQUAL:
		sym_calc_value(e->left.sym);
		sym_calc_value(e->right.sym);
		str1 = sym_get_string_value(e->left.sym);
		str2 = sym_get_string_value(e->right.sym);
		return !strcmp(str1, str2) ? yes : no;
	case E_UNEQUAL:
		sym_calc_value(e->left.sym);
		sym_calc_value(e->right.sym);
		str1 = sym_get_string_value(e->left.sym);
		str2 = sym_get_string_value(e->right.sym);
		return !strcmp(str1, str2) ? no : yes;
	default:
		printf("expr_calc_value: %d?\n", e->type);
		return no;
	}
}

int expr_compare_type(enum expr_type t1, enum expr_type t2)
{
#if 0
	return 1;
#else
	if (t1 == t2)
		return 0;
	switch (t1) {
	case E_EQUAL:
	case E_UNEQUAL:
		if (t2 == E_NOT)
			return 1;
	case E_NOT:
		if (t2 == E_AND)
			return 1;
	case E_AND:
		if (t2 == E_OR)
			return 1;
	case E_OR:
		if (t2 == E_CHOICE)
			return 1;
	case E_CHOICE:
		if (t2 == 0)
			return 1;
	default:
		return -1;
	}
	printf("[%dgt%d?]", t1, t2);
	return 0;
#endif
}

void expr_print(struct expr *e, void (*fn)(void *, const char *), void *data, int prevtoken)
{
	if (!e) {
		fn(data, "y");
		return;
	}

	if (expr_compare_type(prevtoken, e->type) > 0)
		fn(data, "(");
	switch (e->type) {
	case E_SYMBOL:
		if (e->left.sym->name)
			fn(data, e->left.sym->name);
		else
			fn(data, "<choice>");
		break;
	case E_NOT:
		fn(data, "!");
		expr_print(e->left.expr, fn, data, E_NOT);
		break;
	case E_EQUAL:
		fn(data, e->left.sym->name);
		fn(data, "=");
		fn(data, e->right.sym->name);
		break;
	case E_UNEQUAL:
		fn(data, e->left.sym->name);
		fn(data, "!=");
		fn(data, e->right.sym->name);
		break;
	case E_OR:
		expr_print(e->left.expr, fn, data, E_OR);
		fn(data, " || ");
		expr_print(e->right.expr, fn, data, E_OR);
		break;
	case E_AND:
		expr_print(e->left.expr, fn, data, E_AND);
		fn(data, " && ");
		expr_print(e->right.expr, fn, data, E_AND);
		break;
	case E_CHOICE:
		fn(data, e->right.sym->name);
		if (e->left.expr) {
			fn(data, " ^ ");
			expr_print(e->left.expr, fn, data, E_CHOICE);
		}
		break;
	case E_RANGE:
		fn(data, "[");
		fn(data, e->left.sym->name);
		fn(data, " ");
		fn(data, e->right.sym->name);
		fn(data, "]");
		break;
	default:
	  {
		char buf[32];
		sprintf(buf, "<unknown type %d>", e->type);
		fn(data, buf);
		break;
	  }
	}
	if (expr_compare_type(prevtoken, e->type) > 0)
		fn(data, ")");
}

static void expr_print_file_helper(void *data, const char *str)
{
	fwrite(str, strlen(str), 1, data);
}

void expr_fprint(struct expr *e, FILE *out)
{
	expr_print(e, expr_print_file_helper, out, E_NONE);
}