Example #1
0
/* Shared helper to provide toString() and valueOf().  Checks 'this', gets
 * the primitive value to stack top, and optionally coerces with ToString().
 */
duk_ret_t duk_bi_boolean_prototype_tostring_shared(duk_context *ctx) {
	duk_tval *tv;
	duk_hobject *h;
	duk_small_int_t coerce_tostring = duk_get_magic(ctx);

	/* FIXME: there is room to use a shared helper here, many built-ins
	 * check the 'this' type, and if it's an object, check its class,
	 * then get its internal value, etc.
	 */

	duk_push_this(ctx);
	tv = duk_get_tval(ctx, -1);
	DUK_ASSERT(tv != NULL);

	if (DUK_TVAL_IS_BOOLEAN(tv)) {
		goto type_ok;
	} else if (DUK_TVAL_IS_OBJECT(tv)) {
		h = DUK_TVAL_GET_OBJECT(tv);
		DUK_ASSERT(h != NULL);

		if (DUK_HOBJECT_GET_CLASS_NUMBER(h) == DUK_HOBJECT_CLASS_BOOLEAN) {
			duk_get_prop_stridx(ctx, -1, DUK_STRIDX_INT_VALUE);
			DUK_ASSERT(duk_is_boolean(ctx, -1));
			goto type_ok;
		}
	}

	return DUK_RET_TYPE_ERROR;

 type_ok:
	if (coerce_tostring) {
		duk_to_string(ctx, -1);
	}
	return 1;
}
Example #2
0
DUK_INTERNAL duk_bool_t duk_js_equals_helper(duk_hthread *thr, duk_tval *tv_x, duk_tval *tv_y, duk_small_int_t flags) {
	duk_context *ctx = (duk_context *) thr;
	duk_tval *tv_tmp;

	/* If flags != 0 (strict or SameValue), thr can be NULL.  For loose
	 * equals comparison it must be != NULL.
	 */
	DUK_ASSERT(flags != 0 || thr != NULL);

	/*
	 *  Same type?
	 *
	 *  Note: since number values have no explicit tag in the 8-byte
	 *  representation, need the awkward if + switch.
	 */

#if defined(DUK_USE_FASTINT)
	if (DUK_TVAL_IS_FASTINT(tv_x) && DUK_TVAL_IS_FASTINT(tv_y)) {
		if (DUK_TVAL_GET_FASTINT(tv_x) == DUK_TVAL_GET_FASTINT(tv_y)) {
			return 1;
		} else {
			return 0;
		}
	}
	else
#endif
	if (DUK_TVAL_IS_NUMBER(tv_x) && DUK_TVAL_IS_NUMBER(tv_y)) {
		/* Catches both doubles and cases where only one argument is a fastint */
		if (DUK_UNLIKELY((flags & DUK_EQUALS_FLAG_SAMEVALUE) != 0)) {
			/* SameValue */
			return duk__js_samevalue_number(DUK_TVAL_GET_NUMBER(tv_x),
			                                DUK_TVAL_GET_NUMBER(tv_y));
		} else {
			/* equals and strict equals */
			return duk__js_equals_number(DUK_TVAL_GET_NUMBER(tv_x),
			                             DUK_TVAL_GET_NUMBER(tv_y));
		}
	} else if (DUK_TVAL_GET_TAG(tv_x) == DUK_TVAL_GET_TAG(tv_y)) {
		switch (DUK_TVAL_GET_TAG(tv_x)) {
		case DUK_TAG_UNDEFINED:
		case DUK_TAG_NULL: {
			return 1;
		}
		case DUK_TAG_BOOLEAN: {
			return DUK_TVAL_GET_BOOLEAN(tv_x) == DUK_TVAL_GET_BOOLEAN(tv_y);
		}
		case DUK_TAG_POINTER: {
			return DUK_TVAL_GET_POINTER(tv_x) == DUK_TVAL_GET_POINTER(tv_y);
		}
		case DUK_TAG_STRING:
		case DUK_TAG_OBJECT: {
			/* heap pointer comparison suffices */
			return DUK_TVAL_GET_HEAPHDR(tv_x) == DUK_TVAL_GET_HEAPHDR(tv_y);
		}
		case DUK_TAG_BUFFER: {
			if ((flags & (DUK_EQUALS_FLAG_STRICT | DUK_EQUALS_FLAG_SAMEVALUE)) != 0) {
				/* heap pointer comparison suffices */
				return DUK_TVAL_GET_HEAPHDR(tv_x) == DUK_TVAL_GET_HEAPHDR(tv_y);
			} else {
				/* non-strict equality for buffers compares contents */
				duk_hbuffer *h_x = DUK_TVAL_GET_BUFFER(tv_x);
				duk_hbuffer *h_y = DUK_TVAL_GET_BUFFER(tv_y);
				duk_size_t len_x = DUK_HBUFFER_GET_SIZE(h_x);
				duk_size_t len_y = DUK_HBUFFER_GET_SIZE(h_y);
				void *buf_x;
				void *buf_y;
				if (len_x != len_y) {
					return 0;
				}
				buf_x = (void *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_x);
				buf_y = (void *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_y);
				/* if len_x == len_y == 0, buf_x and/or buf_y may
				 * be NULL, but that's OK.
				 */
				DUK_ASSERT(len_x == len_y);
				DUK_ASSERT(len_x == 0 || buf_x != NULL);
				DUK_ASSERT(len_y == 0 || buf_y != NULL);
				return (DUK_MEMCMP(buf_x, buf_y, len_x) == 0) ? 1 : 0;
			}
		}
		case DUK_TAG_LIGHTFUNC: {
			/* At least 'magic' has a significant impact on function
			 * identity.
			 */
			duk_small_uint_t lf_flags_x;
			duk_small_uint_t lf_flags_y;
			duk_c_function func_x;
			duk_c_function func_y;

			DUK_TVAL_GET_LIGHTFUNC(tv_x, func_x, lf_flags_x);
			DUK_TVAL_GET_LIGHTFUNC(tv_y, func_y, lf_flags_y);
			return ((func_x == func_y) && (lf_flags_x == lf_flags_y)) ? 1 : 0;
		}
#if defined(DUK_USE_FASTINT)
		case DUK_TAG_FASTINT:
#endif
		default: {
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_x));
			DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv_y));
			DUK_UNREACHABLE();
			return 0;
		}
		}
	}

	if ((flags & (DUK_EQUALS_FLAG_STRICT | DUK_EQUALS_FLAG_SAMEVALUE)) != 0) {
		return 0;
	}

	DUK_ASSERT(flags == 0);  /* non-strict equality from here on */

	/*
	 *  Types are different; various cases for non-strict comparison
	 *
	 *  Since comparison is symmetric, we use a "swap trick" to reduce
	 *  code size.
	 */

	/* Undefined/null are considered equal (e.g. "null == undefined" -> true). */
	if ((DUK_TVAL_IS_UNDEFINED(tv_x) && DUK_TVAL_IS_NULL(tv_y)) ||
	    (DUK_TVAL_IS_NULL(tv_x) && DUK_TVAL_IS_UNDEFINED(tv_y))) {
		return 1;
	}

	/* Number/string-or-buffer -> coerce string to number (e.g. "'1.5' == 1.5" -> true). */
	if (DUK_TVAL_IS_NUMBER(tv_x) && (DUK_TVAL_IS_STRING(tv_y) || DUK_TVAL_IS_BUFFER(tv_y))) {
		/* the next 'if' is guaranteed to match after swap */
		tv_tmp = tv_x;
		tv_x = tv_y;
		tv_y = tv_tmp;
	}
	if ((DUK_TVAL_IS_STRING(tv_x) || DUK_TVAL_IS_BUFFER(tv_x)) && DUK_TVAL_IS_NUMBER(tv_y)) {
		/* XXX: this is possible without resorting to the value stack */
		duk_double_t d1, d2;
		d2 = DUK_TVAL_GET_NUMBER(tv_y);
		duk_push_tval(ctx, tv_x);
		duk_to_string(ctx, -1);  /* buffer values are coerced first to string here */
		duk_to_number(ctx, -1);
		d1 = duk_require_number(ctx, -1);
		duk_pop(ctx);
		return duk__js_equals_number(d1, d2);
	}

	/* Buffer/string -> compare contents. */
	if (DUK_TVAL_IS_BUFFER(tv_x) && DUK_TVAL_IS_STRING(tv_y)) {
		tv_tmp = tv_x;
		tv_x = tv_y;
		tv_y = tv_tmp;
	}
	if (DUK_TVAL_IS_STRING(tv_x) && DUK_TVAL_IS_BUFFER(tv_y)) {
		duk_hstring *h_x = DUK_TVAL_GET_STRING(tv_x);
		duk_hbuffer *h_y = DUK_TVAL_GET_BUFFER(tv_y);
		duk_size_t len_x = DUK_HSTRING_GET_BYTELEN(h_x);
		duk_size_t len_y = DUK_HBUFFER_GET_SIZE(h_y);
		void *buf_x;
		void *buf_y;
		if (len_x != len_y) {
			return 0;
		}
		buf_x = (void *) DUK_HSTRING_GET_DATA(h_x);
		buf_y = (void *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h_y);
		/* if len_x == len_y == 0, buf_x and/or buf_y may
		 * be NULL, but that's OK.
		 */
		DUK_ASSERT(len_x == len_y);
		DUK_ASSERT(len_x == 0 || buf_x != NULL);
		DUK_ASSERT(len_y == 0 || buf_y != NULL);
		return (DUK_MEMCMP(buf_x, buf_y, len_x) == 0) ? 1 : 0;
	}

	/* Boolean/any -> coerce boolean to number and try again.  If boolean is
	 * compared to a pointer, the final comparison after coercion now always
	 * yields false (as pointer vs. number compares to false), but this is
	 * not special cased.
	 */
	if (DUK_TVAL_IS_BOOLEAN(tv_x)) {
		tv_tmp = tv_x;
		tv_x = tv_y;
		tv_y = tv_tmp;
	}
	if (DUK_TVAL_IS_BOOLEAN(tv_y)) {
		/* ToNumber(bool) is +1.0 or 0.0.  Tagged boolean value is always 0 or 1. */
		duk_bool_t rc;
		DUK_ASSERT(DUK_TVAL_GET_BOOLEAN(tv_y) == 0 || DUK_TVAL_GET_BOOLEAN(tv_y) == 1);
		duk_push_tval(ctx, tv_x);
		duk_push_int(ctx, DUK_TVAL_GET_BOOLEAN(tv_y));
		rc = duk_js_equals_helper(thr, duk_get_tval(ctx, -2), duk_get_tval(ctx, -1), 0 /*flags:nonstrict*/);
		duk_pop_2(ctx);
		return rc;
	}

	/* String-number-buffer/object -> coerce object to primitive (apparently without hint), then try again. */
	if ((DUK_TVAL_IS_STRING(tv_x) || DUK_TVAL_IS_NUMBER(tv_x) || DUK_TVAL_IS_BUFFER(tv_x)) &&
	    DUK_TVAL_IS_OBJECT(tv_y)) {
		tv_tmp = tv_x;
		tv_x = tv_y;
		tv_y = tv_tmp;
	}
	if (DUK_TVAL_IS_OBJECT(tv_x) &&
	    (DUK_TVAL_IS_STRING(tv_y) || DUK_TVAL_IS_NUMBER(tv_y) || DUK_TVAL_IS_BUFFER(tv_y))) {
		duk_bool_t rc;
		duk_push_tval(ctx, tv_x);
		duk_push_tval(ctx, tv_y);
		duk_to_primitive(ctx, -2, DUK_HINT_NONE);  /* apparently no hint? */
		rc = duk_js_equals_helper(thr, duk_get_tval(ctx, -2), duk_get_tval(ctx, -1), 0 /*flags:nonstrict*/);
		duk_pop_2(ctx);
		return rc;
	}

	/* Nothing worked -> not equal. */
	return 0;
}