DUK_INTERNAL duk_uint_t duk_hbufferobject_clamp_bytelength(duk_hbufferobject *h_bufobj, duk_uint_t len) {
	duk_uint_t buf_size;
	duk_uint_t buf_avail;

	DUK_ASSERT(h_bufobj != NULL);
	DUK_ASSERT(h_bufobj->buf != NULL);

	buf_size = DUK_HBUFFER_GET_SIZE(h_bufobj->buf);
	if (h_bufobj->offset > buf_size) {
		/* Slice starting point is beyond current length. */
		return 0;
	}
	buf_avail = buf_size - h_bufobj->offset;

	return buf_avail >= len ? len : buf_avail;
}
Beispiel #2
0
DUK_LOCAL duk_uint8_t *duk__dump_buffer_prop(duk_hthread *thr, duk_uint8_t *p, duk_bufwriter_ctx *bw_ctx, duk_hobject *func, duk_small_uint_t stridx) {
	duk_tval *tv;

	tv = duk_hobject_find_existing_entry_tval_ptr(thr->heap, (duk_hobject *) func, DUK_HTHREAD_GET_STRING(thr, stridx));
	if (tv != NULL && DUK_TVAL_IS_BUFFER(tv)) {
		duk_hbuffer *h_buf;
		h_buf = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h_buf != NULL);
		DUK_ASSERT(DUK_HBUFFER_MAX_BYTELEN <= 0x7fffffffUL);  /* ensures no overflow */
		p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4 + DUK_HBUFFER_GET_SIZE(h_buf), p);
		p = duk__dump_hbuffer_raw(thr, p, h_buf);
	} else {
		p = DUK_BW_ENSURE_RAW(thr, bw_ctx, 4, p);
		DUK_RAW_WRITE_U32_BE(p, 0);
	}
	return p;
}
Beispiel #3
0
DUK_LOCAL duk_uint8_t *duk__dump_hbuffer_raw(duk_hthread *thr, duk_uint8_t *p, duk_hbuffer *h) {
	duk_size_t len;
	duk_uint32_t tmp32;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(h != NULL);
	DUK_UNREF(thr);

	len = DUK_HBUFFER_GET_SIZE(h);
	DUK_ASSERT(len <= 0xffffffffUL);  /* buffer limits */
	tmp32 = (duk_uint32_t) len;
	DUK_RAW_WRITE_U32_BE(p, tmp32);
	DUK_MEMCPY((void *) p,
	           (const void *) DUK_HBUFFER_GET_DATA_PTR(thr->heap, h),
	           len);
	p += len;
	return p;
}
Beispiel #4
0
void duk_to_fixed_buffer(duk_context *ctx, duk_idx_t index) {
	duk_hbuffer_dynamic *h_src;
	duk_uint8_t *data;
	duk_size_t size;

	index = duk_require_normalize_index(ctx, index);

	h_src = (duk_hbuffer_dynamic *) duk_require_hbuffer(ctx, index);
	DUK_ASSERT(h_src != NULL);
	if (!DUK_HBUFFER_HAS_DYNAMIC(h_src)) {
		return;
	}

	size = DUK_HBUFFER_GET_SIZE(h_src);
	data = (duk_uint8_t *) duk_push_fixed_buffer(ctx, size);
	if (size > 0U) {
		DUK_ASSERT(data != NULL);
		DUK_MEMCPY(data, DUK_HBUFFER_DYNAMIC_GET_CURR_DATA_PTR(h_src), size);
	}

	duk_replace(ctx, index);
}
Beispiel #5
0
duk_bool_t duk_js_toboolean(duk_tval *tv) {
	switch (DUK_TVAL_GET_TAG(tv)) {
	case DUK_TAG_UNDEFINED:
	case DUK_TAG_NULL:
		return 0;
	case DUK_TAG_BOOLEAN:
		return DUK_TVAL_GET_BOOLEAN(tv);
	case DUK_TAG_STRING: {
		duk_hstring *h = DUK_TVAL_GET_STRING(tv);
		DUK_ASSERT(h != NULL);
		return (h->blen > 0 ? 1 : 0);
	}
	case DUK_TAG_OBJECT: {
		return 1;
	}
	case DUK_TAG_BUFFER: {
		/* mimic semantics for strings */
		duk_hbuffer *h = DUK_TVAL_GET_BUFFER(tv);
		DUK_ASSERT(h != NULL);
		return (DUK_HBUFFER_GET_SIZE(h) > 0 ? 1 : 0);
	}
	case DUK_TAG_POINTER: {
		void *p = DUK_TVAL_GET_POINTER(tv);
		return (p != NULL ? 1 : 0);
	}
	default: {
		/* number */
		int c;
		DUK_ASSERT(DUK_TVAL_IS_NUMBER(tv));
		c = DUK_FPCLASSIFY(DUK_TVAL_GET_NUMBER(tv));
		if (c == DUK_FP_ZERO || c == DUK_FP_NAN) {
			return 0;
		} else {
			return 1;
		}
	}
	}
	DUK_UNREACHABLE();
}
Beispiel #6
0
void duk_hbuffer_insert_bytes(duk_hthread *thr, duk_hbuffer_dynamic *buf, size_t offset, duk_uint8_t *data, size_t length) {
	char *p;

	/* XXX: allow inserts with offset > curr_size? i.e., insert zeroes automatically? */

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(buf != NULL);
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(buf));
	DUK_ASSERT_DISABLE(offset >= 0);  /* unsigned, so always true */
	DUK_ASSERT(offset <= DUK_HBUFFER_GET_SIZE(buf));  /* equality is OK (= append) */
	DUK_ASSERT(data != NULL);
	DUK_ASSERT_DISABLE(length >= 0);  /* unsigned, so always true */

	if (length == 0) {
		return;
	}

	if (DUK_HBUFFER_DYNAMIC_GET_SPARE_SIZE(buf) < length) {
		duk_hbuffer_resize(thr,
		                   buf,
		                   DUK_HBUFFER_GET_SIZE(buf),
		                   duk__add_spare(DUK_HBUFFER_GET_SIZE(buf) + length));
	}
	DUK_ASSERT(DUK_HBUFFER_DYNAMIC_GET_SPARE_SIZE(buf) >= length);

	p = (char *) DUK_HBUFFER_DYNAMIC_GET_CURR_DATA_PTR(buf);
	if (offset < DUK_HBUFFER_GET_SIZE(buf)) {
		/* not an append */

		DUK_ASSERT(DUK_HBUFFER_GET_SIZE(buf) - offset > 0);  /* not a zero byte memmove */
		DUK_MEMMOVE((void *) (p + offset + length),
		            (void *) (p + offset),
		            DUK_HBUFFER_GET_SIZE(buf) - offset);
	}

	DUK_MEMCPY((void *) (p + offset),
	           data,
	           length);

	buf->size += length;
}
Beispiel #7
0
/* Raw helper to extract internal information / statistics about a value.
 * The return values are version specific and must not expose anything
 * that would lead to security issues (e.g. exposing compiled function
 * 'data' buffer might be an issue).  Currently only counts and sizes and
 * such are given so there should not be a security impact.
 */
duk_ret_t duk_bi_duktape_object_info(duk_context *ctx) {
	duk_tval *tv;
	duk_heaphdr *h;
	duk_int_t i, n;

	tv = duk_get_tval(ctx, 0);
	DUK_ASSERT(tv != NULL);  /* because arg count is 1 */

	duk_push_array(ctx);  /* -> [ val arr ] */

	/* type tag (public) */
	duk_push_int(ctx, duk_get_type(ctx, 0));

	/* address */
	if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
		h = DUK_TVAL_GET_HEAPHDR(tv);
		duk_push_pointer(ctx, (void *) h);
	} else {
		goto done;
	}
	DUK_ASSERT(h != NULL);

	/* refcount */
#ifdef DUK_USE_REFERENCE_COUNTING
	duk_push_int(ctx, DUK_HEAPHDR_GET_REFCOUNT(h));
#else
	duk_push_undefined(ctx);
#endif

	/* heaphdr size and additional allocation size, followed by
	 * type specific stuff (with varying value count)
	 */
	switch ((duk_small_int_t) DUK_HEAPHDR_GET_TYPE(h)) {
	case DUK_HTYPE_STRING: {
		duk_hstring *h_str = (duk_hstring *) h;
		duk_push_int(ctx, (int) (sizeof(duk_hstring) + DUK_HSTRING_GET_BYTELEN(h_str) + 1));
		break;
	}
	case DUK_HTYPE_OBJECT: {
		duk_hobject *h_obj = (duk_hobject *) h;
		duk_int_t hdr_size;
		if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h_obj)) {
			hdr_size = (duk_int_t) sizeof(duk_hcompiledfunction);
		} else if (DUK_HOBJECT_IS_NATIVEFUNCTION(h_obj)) {
			hdr_size = (duk_int_t) sizeof(duk_hnativefunction);
		} else if (DUK_HOBJECT_IS_THREAD(h_obj)) {
			hdr_size = (duk_int_t) sizeof(duk_hthread);
		} else {
			hdr_size = (duk_int_t) sizeof(duk_hobject);
		}
		duk_push_int(ctx, (int) hdr_size);
		duk_push_int(ctx, (int) DUK_HOBJECT_E_ALLOC_SIZE(h_obj));
		duk_push_int(ctx, (int) h_obj->e_size);
		duk_push_int(ctx, (int) h_obj->e_used);
		duk_push_int(ctx, (int) h_obj->a_size);
		duk_push_int(ctx, (int) h_obj->h_size);
		if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h_obj)) {
			duk_hbuffer *h_data = ((duk_hcompiledfunction *) h_obj)->data;
			if (h_data) {
				duk_push_int(ctx, DUK_HBUFFER_GET_SIZE(h_data));
			} else {
				duk_push_int(ctx, 0);
			}
		}
		break;
	}
	case DUK_HTYPE_BUFFER: {
		duk_hbuffer *h_buf = (duk_hbuffer *) h;
		if (DUK_HBUFFER_HAS_DYNAMIC(h_buf)) {
			/* XXX: when usable_size == 0, dynamic buf ptr may now be NULL, in which case
			 * the second allocation does not exist.
			 */
			duk_hbuffer_dynamic *h_dyn = (duk_hbuffer_dynamic *) h;
			duk_push_int(ctx, (int) (sizeof(duk_hbuffer_dynamic)));
			duk_push_int(ctx, (int) (DUK_HBUFFER_DYNAMIC_GET_ALLOC_SIZE(h_dyn)));
		} else {
			duk_push_int(ctx, (int) (sizeof(duk_hbuffer_fixed) + DUK_HBUFFER_GET_SIZE(h_buf) + 1));
		}
		break;

	}
	}

 done:
	/* set values into ret array */
	/* FIXME: primitive to make array from valstack slice */
	n = duk_get_top(ctx);
	for (i = 2; i < n; i++) {
		duk_dup(ctx, i);
		duk_put_prop_index(ctx, 1, i - 2);
	}
	duk_dup(ctx, 1);
	return 1;
}
Beispiel #8
0
void duk_hobject_enumerator_create(duk_context *ctx, duk_small_uint_t enum_flags) {
	duk_hthread *thr = (duk_hthread *) ctx;
	duk_hobject *enum_target;
	duk_hobject *curr;
	duk_hobject *res;
#if defined(DUK_USE_ES6_PROXY)
	duk_hobject *h_proxy_target;
	duk_hobject *h_proxy_handler;
	duk_hobject *h_trap_result;
#endif
	duk_uint_fast32_t i, len;  /* used for array, stack, and entry indices */

	DUK_ASSERT(ctx != NULL);

	DUK_DDD(DUK_DDDPRINT("create enumerator, stack top: %ld", (long) duk_get_top(ctx)));

	enum_target = duk_require_hobject(ctx, -1);
	DUK_ASSERT(enum_target != NULL);

	duk_push_object_internal(ctx);
	res = duk_require_hobject(ctx, -1);

	DUK_DDD(DUK_DDDPRINT("created internal object"));

	/* [enum_target res] */

	/* Target must be stored so that we can recheck whether or not
	 * keys still exist when we enumerate.  This is not done if the
	 * enumeration result comes from a proxy trap as there is no
	 * real object to check against.
	 */
	duk_push_hobject(ctx, enum_target);
	duk_put_prop_stridx(ctx, -2, DUK_STRIDX_INT_TARGET);

	/* Initialize index so that we skip internal control keys. */
	duk_push_int(ctx, DUK__ENUM_START_INDEX);
	duk_put_prop_stridx(ctx, -2, DUK_STRIDX_INT_NEXT);

	/*
	 *  Proxy object handling
	 */

#if defined(DUK_USE_ES6_PROXY)
	if (DUK_LIKELY((enum_flags & DUK_ENUM_NO_PROXY_BEHAVIOR) != 0)) {
		goto skip_proxy;
	}
	if (DUK_LIKELY(!duk_hobject_proxy_check(thr,
	                                        enum_target,
	                                        &h_proxy_target,
	                                        &h_proxy_handler))) {
		goto skip_proxy;
	}

	DUK_DDD(DUK_DDDPRINT("proxy enumeration"));
	duk_push_hobject(ctx, h_proxy_handler);
	if (!duk_get_prop_stridx(ctx, -1, DUK_STRIDX_ENUMERATE)) {
		/* No need to replace the 'enum_target' value in stack, only the
		 * enum_target reference.  This also ensures that the original
		 * enum target is reachable, which keeps the proxy and the proxy
		 * target reachable.  We do need to replace the internal _target.
		 */
		DUK_DDD(DUK_DDDPRINT("no enumerate trap, enumerate proxy target instead"));
		DUK_DDD(DUK_DDDPRINT("h_proxy_target=%!O", (duk_heaphdr *) h_proxy_target));
		enum_target = h_proxy_target;

		duk_push_hobject(ctx, enum_target);  /* -> [ ... enum_target res handler undefined target ] */
		duk_put_prop_stridx(ctx, -4, DUK_STRIDX_INT_TARGET);

		duk_pop_2(ctx);  /* -> [ ... enum_target res ] */
		goto skip_proxy;
	}

	/* [ ... enum_target res handler trap ] */
	duk_insert(ctx, -2);
	duk_push_hobject(ctx, h_proxy_target);    /* -> [ ... enum_target res trap handler target ] */
	duk_call_method(ctx, 1 /*nargs*/);        /* -> [ ... enum_target res trap_result ] */
	h_trap_result = duk_require_hobject(ctx, -1);
	DUK_UNREF(h_trap_result);

	/* Copy trap result keys into the enumerator object. */
	len = (duk_uint_fast32_t) duk_get_length(ctx, -1);
	for (i = 0; i < len; i++) {
		/* XXX: not sure what the correct semantic details are here,
		 * e.g. handling of missing values (gaps), handling of non-array
		 * trap results, etc.
		 *
		 * For keys, we simply skip non-string keys which seems to be
		 * consistent with how e.g. Object.keys() will process proxy trap
		 * results (ES6 draft, Section 19.1.2.14).
		 */
		if (duk_get_prop_index(ctx, -1, i) && duk_is_string(ctx, -1)) {
			/* [ ... enum_target res trap_result val ] */
			duk_push_true(ctx);
			/* [ ... enum_target res trap_result val true ] */
			duk_put_prop(ctx, -4);
		} else {
			duk_pop(ctx);
		}
	}
	/* [ ... enum_target res trap_result ] */
	duk_pop(ctx);
	duk_remove(ctx, -2);

	/* [ ... res ] */

	/* The internal _target property is kept pointing to the original
	 * enumeration target (the proxy object), so that the enumerator
	 * 'next' operation can read property values if so requested.  The
	 * fact that the _target is a proxy disables key existence check
	 * during enumeration.
	 */
	DUK_DDD(DUK_DDDPRINT("proxy enumeration, final res: %!O", (duk_heaphdr *) res));
	goto compact_and_return;

 skip_proxy:
#endif  /* DUK_USE_ES6_PROXY */

	curr = enum_target;
	while (curr) {
		/*
		 *  Virtual properties.
		 *
		 *  String and buffer indices are virtual and always enumerable,
		 *  'length' is virtual and non-enumerable.  Array and arguments
		 *  object props have special behavior but are concrete.
		 */

		if (DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(curr) ||
		    DUK_HOBJECT_HAS_EXOTIC_BUFFEROBJ(curr)) {
			/* String and buffer enumeration behavior is identical now,
			 * so use shared handler.
			 */
			if (DUK_HOBJECT_HAS_EXOTIC_STRINGOBJ(curr)) {
				duk_hstring *h_val;
				h_val = duk_hobject_get_internal_value_string(thr->heap, curr);
				DUK_ASSERT(h_val != NULL);  /* string objects must not created without internal value */
				len = (duk_uint_fast32_t) DUK_HSTRING_GET_CHARLEN(h_val);
			} else {
				duk_hbuffer *h_val;
				DUK_ASSERT(DUK_HOBJECT_HAS_EXOTIC_BUFFEROBJ(curr));
				h_val = duk_hobject_get_internal_value_buffer(thr->heap, curr);
				DUK_ASSERT(h_val != NULL);  /* buffer objects must not created without internal value */
				len = (duk_uint_fast32_t) DUK_HBUFFER_GET_SIZE(h_val);
			}

			for (i = 0; i < len; i++) {
				duk_hstring *k;

				k = duk_heap_string_intern_u32_checked(thr, i);
				DUK_ASSERT(k);
				duk_push_hstring(ctx, k);
				duk_push_true(ctx);

				/* [enum_target res key true] */
				duk_put_prop(ctx, -3);

				/* [enum_target res] */
			}

			/* 'length' property is not enumerable, but is included if
			 * non-enumerable properties are requested.
			 */

			if (enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE) {
				duk_push_hstring_stridx(ctx, DUK_STRIDX_LENGTH);
				duk_push_true(ctx);
				duk_put_prop(ctx, -3);
			}
		} else if (DUK_HOBJECT_HAS_EXOTIC_DUKFUNC(curr)) {
			if (enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE) {
				duk_push_hstring_stridx(ctx, DUK_STRIDX_LENGTH);
				duk_push_true(ctx);
				duk_put_prop(ctx, -3);
			}
		}

		/*
		 *  Array part
		 *
		 *  Note: ordering between array and entry part must match 'abandon array'
		 *  behavior in duk_hobject_props.c: key order after an array is abandoned
		 *  must be the same.
		 */

		for (i = 0; i < (duk_uint_fast32_t) curr->a_size; i++) {
			duk_hstring *k;
			duk_tval *tv;

			tv = DUK_HOBJECT_A_GET_VALUE_PTR(curr, i);
			if (DUK_TVAL_IS_UNDEFINED_UNUSED(tv)) {
				continue;
			}
			k = duk_heap_string_intern_u32_checked(thr, i);
			DUK_ASSERT(k);

			duk_push_hstring(ctx, k);
			duk_push_true(ctx);

			/* [enum_target res key true] */
			duk_put_prop(ctx, -3);

			/* [enum_target res] */
		}

		/*
		 *  Entries part
		 */

		for (i = 0; i < (duk_uint_fast32_t) curr->e_next; i++) {
			duk_hstring *k;

			k = DUK_HOBJECT_E_GET_KEY(curr, i);
			if (!k) {
				continue;
			}
			if (!DUK_HOBJECT_E_SLOT_IS_ENUMERABLE(curr, i) &&
			    !(enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE)) {
				continue;
			}
			if (DUK_HSTRING_HAS_INTERNAL(k) &&
			    !(enum_flags & DUK_ENUM_INCLUDE_INTERNAL)) {
				continue;
			}
			if ((enum_flags & DUK_ENUM_ARRAY_INDICES_ONLY) &&
			    (DUK_HSTRING_GET_ARRIDX_SLOW(k) == DUK_HSTRING_NO_ARRAY_INDEX)) {
				continue;
			}

			DUK_ASSERT(DUK_HOBJECT_E_SLOT_IS_ACCESSOR(curr, i) ||
			           !DUK_TVAL_IS_UNDEFINED_UNUSED(&DUK_HOBJECT_E_GET_VALUE_PTR(curr, i)->v));

			duk_push_hstring(ctx, k);
			duk_push_true(ctx);

			/* [enum_target res key true] */
			duk_put_prop(ctx, -3);

			/* [enum_target res] */
		}

		if (enum_flags & DUK_ENUM_OWN_PROPERTIES_ONLY) {
			break;
		}

		curr = curr->prototype;
	}

	/* [enum_target res] */

	duk_remove(ctx, -2);

	/* [res] */

	if ((enum_flags & (DUK_ENUM_ARRAY_INDICES_ONLY | DUK_ENUM_SORT_ARRAY_INDICES)) ==
	                  (DUK_ENUM_ARRAY_INDICES_ONLY | DUK_ENUM_SORT_ARRAY_INDICES)) {
		/*
		 *  Some E5/E5.1 algorithms require that array indices are iterated
		 *  in a strictly ascending order.  This is the case for e.g.
		 *  Array.prototype.forEach() and JSON.stringify() PropertyList
		 *  handling.
		 *
		 *  To ensure this property for arrays with an array part (and
		 *  arbitrary objects too, since e.g. forEach() can be applied
		 *  to an array), the caller can request that we sort the keys
		 *  here.
		 */

		/* XXX: avoid this at least when enum_target is an Array, it has an
		 * array part, and no ancestor properties were included?  Not worth
		 * it for JSON, but maybe worth it for forEach().
		 */

		/* XXX: may need a 'length' filter for forEach()
		 */
		DUK_DDD(DUK_DDDPRINT("sort array indices by caller request"));
		duk__sort_array_indices(res);
	}

#if defined(DUK_USE_ES6_PROXY)
 compact_and_return:
#endif
	/* compact; no need to seal because object is internal */
	duk_hobject_compact_props(thr, res);

	DUK_DDD(DUK_DDDPRINT("created enumerator object: %!iT", (duk_tval *) duk_get_tval(ctx, -1)));
}
Beispiel #9
0
void duk_hbuffer_insert_slice(duk_hthread *thr, duk_hbuffer_dynamic *buf, size_t dst_offset, size_t src_offset, size_t length) {
	char *p;
	size_t src_end_offset;  /* source end (exclusive) in initial buffer */
	size_t len;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(buf != NULL);
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(buf));
	DUK_ASSERT_DISABLE(dst_offset >= 0);                           /* always true */
	DUK_ASSERT(dst_offset <= DUK_HBUFFER_GET_SIZE(buf));           /* allow equality */
	DUK_ASSERT_DISABLE(src_offset >= 0);                           /* always true */
	DUK_ASSERT(src_offset <= DUK_HBUFFER_GET_SIZE(buf));           /* allow equality */
	DUK_ASSERT_DISABLE(length >= 0);                               /* always true */
	DUK_ASSERT(src_offset + length <= DUK_HBUFFER_GET_SIZE(buf));  /* allow equality */

	if (length == 0) {
		return;
	}

	if (DUK_HBUFFER_DYNAMIC_GET_SPARE_SIZE(buf) < length) {
		duk_hbuffer_resize(thr,
		                   buf,
		                   DUK_HBUFFER_GET_SIZE(buf),
		                   duk__add_spare(DUK_HBUFFER_GET_SIZE(buf) + length));
	}
	DUK_ASSERT(DUK_HBUFFER_DYNAMIC_GET_SPARE_SIZE(buf) >= length);

	p = (char *) DUK_HBUFFER_DYNAMIC_GET_CURR_DATA_PTR(buf);

	/*
	 *  src_offset and dst_offset refer to the state of the buffer
	 *  before any changes are made.  This must be taken into account
	 *  when moving data around; in particular, the source data may
	 *  "straddle" the dst_offset, so the insert may need to be handled
	 *  in two pieces.
	 */

	src_end_offset = src_offset + length;

	/* create a hole for the insert */
	len = DUK_HBUFFER_GET_SIZE(buf) - dst_offset;
	if (len > 0) {
		DUK_MEMMOVE(p + dst_offset + length,
		            p + dst_offset,
		            len);
	}

	if (src_offset < dst_offset) {
		if (src_end_offset <= dst_offset) {
			/* entire source is before 'dst_offset' */
			DUK_MEMCPY(p + dst_offset,
			           p + src_offset,
			           length);
		} else {
			/* part of the source is before 'dst_offset'; straddles */
			len = dst_offset - src_offset;
			DUK_ASSERT(len >= 1 && len < length);
			DUK_ASSERT(length - len >= 1);
			DUK_MEMCPY(p + dst_offset,
			           p + src_offset,
			           len);
			DUK_MEMCPY(p + dst_offset + len,
			           p + src_offset + length + len,  /* take above memmove() into account */
			           length - len);
		}
	} else {
		/* entire source is after 'dst_offset' */
		DUK_MEMCPY(p + dst_offset,
		           p + src_offset + length,  /* take above memmove() into account */
		           length);
	}

	buf->size += length;
}
Beispiel #10
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;
}
/* Raw helper to extract internal information / statistics about a value.
 * The return values are version specific and must not expose anything
 * that would lead to security issues (e.g. exposing compiled function
 * 'data' buffer might be an issue).  Currently only counts and sizes and
 * such are given so there should not be a security impact.
 */
DUK_INTERNAL duk_ret_t duk_bi_duktape_object_info(duk_context *ctx) {
	duk_hthread *thr = (duk_hthread *) ctx;
	duk_tval *tv;
	duk_heaphdr *h;
	duk_int_t i, n;

	DUK_UNREF(thr);

	/* result array */
	duk_push_array(ctx);  /* -> [ val arr ] */

	/* type tag (public) */
	duk_push_int(ctx, duk_get_type(ctx, 0));

	/* address */
	tv = duk_get_tval(ctx, 0);
	DUK_ASSERT(tv != NULL);  /* because arg count is 1 */
	if (DUK_TVAL_IS_HEAP_ALLOCATED(tv)) {
		h = DUK_TVAL_GET_HEAPHDR(tv);
		duk_push_pointer(ctx, (void *) h);
	} else {
		/* internal type tag */
		duk_push_int(ctx, (duk_int_t) DUK_TVAL_GET_TAG(tv));
		goto done;
	}
	DUK_ASSERT(h != NULL);

	/* refcount */
#ifdef DUK_USE_REFERENCE_COUNTING
	duk_push_size_t(ctx, DUK_HEAPHDR_GET_REFCOUNT(h));
#else
	duk_push_undefined(ctx);
#endif

	/* heaphdr size and additional allocation size, followed by
	 * type specific stuff (with varying value count)
	 */
	switch ((duk_small_int_t) DUK_HEAPHDR_GET_TYPE(h)) {
	case DUK_HTYPE_STRING: {
		duk_hstring *h_str = (duk_hstring *) h;
		duk_push_uint(ctx, (duk_uint_t) (sizeof(duk_hstring) + DUK_HSTRING_GET_BYTELEN(h_str) + 1));
		break;
	}
	case DUK_HTYPE_OBJECT: {
		duk_hobject *h_obj = (duk_hobject *) h;
		duk_small_uint_t hdr_size;
		if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h_obj)) {
			hdr_size = (duk_small_uint_t) sizeof(duk_hcompiledfunction);
		} else if (DUK_HOBJECT_IS_NATIVEFUNCTION(h_obj)) {
			hdr_size = (duk_small_uint_t) sizeof(duk_hnativefunction);
		} else if (DUK_HOBJECT_IS_THREAD(h_obj)) {
			hdr_size = (duk_small_uint_t) sizeof(duk_hthread);
#if defined(DUK_USE_BUFFEROBJECT_SUPPORT)
		} else if (DUK_HOBJECT_IS_BUFFEROBJECT(h_obj)) {
			hdr_size = (duk_small_uint_t) sizeof(duk_hbufferobject);
#endif
		} else {
			hdr_size = (duk_small_uint_t) sizeof(duk_hobject);
		}
		duk_push_uint(ctx, (duk_uint_t) hdr_size);
		duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_P_ALLOC_SIZE(h_obj));
		duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_GET_ESIZE(h_obj));
		/* Note: e_next indicates the number of gc-reachable entries
		 * in the entry part, and also indicates the index where the
		 * next new property would be inserted.  It does *not* indicate
		 * the number of non-NULL keys present in the object.  That
		 * value could be counted separately but requires a pass through
		 * the key list.
		 */
		duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_GET_ENEXT(h_obj));
		duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_GET_ASIZE(h_obj));
		duk_push_uint(ctx, (duk_uint_t) DUK_HOBJECT_GET_HSIZE(h_obj));
		if (DUK_HOBJECT_IS_COMPILEDFUNCTION(h_obj)) {
			duk_hbuffer *h_data = (duk_hbuffer *) DUK_HCOMPILEDFUNCTION_GET_DATA(thr->heap, (duk_hcompiledfunction *) h_obj);
			if (h_data) {
				duk_push_uint(ctx, (duk_uint_t) DUK_HBUFFER_GET_SIZE(h_data));
			} else {
				duk_push_uint(ctx, 0);
			}
		}
		break;
	}
	case DUK_HTYPE_BUFFER: {
		duk_hbuffer *h_buf = (duk_hbuffer *) h;
		if (DUK_HBUFFER_HAS_DYNAMIC(h_buf)) {
			if (DUK_HBUFFER_HAS_EXTERNAL(h_buf)) {
				duk_push_uint(ctx, (duk_uint_t) (sizeof(duk_hbuffer_external)));
			} else {
				/* When alloc_size == 0 the second allocation may not
				 * actually exist.
				 */
				duk_push_uint(ctx, (duk_uint_t) (sizeof(duk_hbuffer_dynamic)));
			}
			duk_push_uint(ctx, (duk_uint_t) (DUK_HBUFFER_GET_SIZE(h_buf)));
		} else {
			duk_push_uint(ctx, (duk_uint_t) (sizeof(duk_hbuffer_fixed) + DUK_HBUFFER_GET_SIZE(h_buf) + 1));
		}
		break;

	}
	}

 done:
	/* set values into ret array */
	/* XXX: primitive to make array from valstack slice */
	n = duk_get_top(ctx);
	for (i = 2; i < n; i++) {
		duk_dup(ctx, i);
		duk_put_prop_index(ctx, 1, i - 2);
	}
	duk_dup(ctx, 1);
	return 1;
}
Beispiel #12
0
void duk_hobject_enumerator_create(duk_context *ctx, int enum_flags) {
    duk_hthread *thr = (duk_hthread *) ctx;
    duk_hobject *target;
    duk_hobject *curr;
    duk_hobject *res;

    DUK_ASSERT(ctx != NULL);

    DUK_DDDPRINT("create enumerator, stack top: %d", duk_get_top(ctx));

    target = duk_require_hobject(ctx, -1);
    DUK_ASSERT(target != NULL);

    duk_push_object_internal(ctx);

    DUK_DDDPRINT("created internal object");

    /* [target res] */

    duk_push_hstring_stridx(ctx, DUK_STRIDX_INT_TARGET);
    duk_push_hobject(ctx, target);
    duk_put_prop(ctx, -3);

    /* initialize index so that we skip internal control keys */
    duk_push_hstring_stridx(ctx, DUK_STRIDX_INT_NEXT);
    duk_push_int(ctx, DUK__ENUM_START_INDEX);
    duk_put_prop(ctx, -3);

    curr = target;
    while (curr) {
        duk_uint32_t i, len;

        /*
         *  Virtual properties.
         *
         *  String and buffer indices are virtual and always enumerable,
         *  'length' is virtual and non-enumerable.  Array and arguments
         *  object props have special behavior but are concrete.
         */

        if (DUK_HOBJECT_HAS_SPECIAL_STRINGOBJ(curr) ||
                DUK_HOBJECT_HAS_SPECIAL_BUFFEROBJ(curr)) {
            /* String and buffer enumeration behavior is identical now,
             * so use shared handler.
             */
            if (DUK_HOBJECT_HAS_SPECIAL_STRINGOBJ(curr)) {
                duk_hstring *h_val;
                h_val = duk_hobject_get_internal_value_string(thr->heap, curr);
                DUK_ASSERT(h_val != NULL);  /* string objects must not created without internal value */
                len = DUK_HSTRING_GET_CHARLEN(h_val);
            } else {
                duk_hbuffer *h_val;
                DUK_ASSERT(DUK_HOBJECT_HAS_SPECIAL_BUFFEROBJ(curr));
                h_val = duk_hobject_get_internal_value_buffer(thr->heap, curr);
                DUK_ASSERT(h_val != NULL);  /* buffer objects must not created without internal value */
                len = DUK_HBUFFER_GET_SIZE(h_val);
            }

            /* FIXME: type for 'i' to match string max len (duk_uint32_t) */
            for (i = 0; i < len; i++) {
                duk_hstring *k;

                k = duk_heap_string_intern_u32_checked(thr, i);
                DUK_ASSERT(k);
                duk_push_hstring(ctx, k);
                duk_push_true(ctx);

                /* [target res key true] */
                duk_put_prop(ctx, -3);

                /* [target res] */
            }

            /* 'length' property is not enumerable, but is included if
             * non-enumerable properties are requested.
             */

            if (enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE) {
                duk_push_hstring_stridx(ctx, DUK_STRIDX_LENGTH);
                duk_push_true(ctx);
                duk_put_prop(ctx, -3);
            }
        } else if (DUK_HOBJECT_HAS_SPECIAL_DUKFUNC(curr)) {
            if (enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE) {
                duk_push_hstring_stridx(ctx, DUK_STRIDX_LENGTH);
                duk_push_true(ctx);
                duk_put_prop(ctx, -3);
            }
        }

        /*
         *  Array part
         *
         *  Note: ordering between array and entry part must match 'abandon array'
         *  behavior in duk_hobject_props.c: key order after an array is abandoned
         *  must be the same.
         */

        for (i = 0; i < curr->a_size; i++) {
            duk_hstring *k;
            duk_tval *tv;

            tv = DUK_HOBJECT_A_GET_VALUE_PTR(curr, i);
            if (DUK_TVAL_IS_UNDEFINED_UNUSED(tv)) {
                continue;
            }
            k = duk_heap_string_intern_u32_checked(thr, i);
            DUK_ASSERT(k);

            duk_push_hstring(ctx, k);
            duk_push_true(ctx);

            /* [target res key true] */
            duk_put_prop(ctx, -3);

            /* [target res] */
        }

        /*
         *  Entries part
         */

        for (i = 0; i < curr->e_used; i++) {
            duk_hstring *k;

            k = DUK_HOBJECT_E_GET_KEY(curr, i);
            if (!k) {
                continue;
            }
            if (!DUK_HOBJECT_E_SLOT_IS_ENUMERABLE(curr, i) &&
                    !(enum_flags & DUK_ENUM_INCLUDE_NONENUMERABLE)) {
                continue;
            }
            if (DUK_HSTRING_HAS_INTERNAL(k) &&
                    !(enum_flags & DUK_ENUM_INCLUDE_INTERNAL)) {
                continue;
            }
            if ((enum_flags & DUK_ENUM_ARRAY_INDICES_ONLY) &&
                    (DUK_HSTRING_GET_ARRIDX_SLOW(k) == DUK_HSTRING_NO_ARRAY_INDEX)) {
                continue;
            }

            DUK_ASSERT(DUK_HOBJECT_E_SLOT_IS_ACCESSOR(curr, i) ||
                       !DUK_TVAL_IS_UNDEFINED_UNUSED(&DUK_HOBJECT_E_GET_VALUE_PTR(curr, i)->v));

            duk_push_hstring(ctx, k);
            duk_push_true(ctx);

            /* [target res key true] */
            duk_put_prop(ctx, -3);

            /* [target res] */
        }

        if (enum_flags & DUK_ENUM_OWN_PROPERTIES_ONLY) {
            break;
        }

        curr = curr->prototype;
    }

    /* [target res] */

    duk_remove(ctx, -2);
    res = duk_require_hobject(ctx, -1);

    /* [res] */

    if ((enum_flags & (DUK_ENUM_ARRAY_INDICES_ONLY | DUK_ENUM_SORT_ARRAY_INDICES)) ==
            (DUK_ENUM_ARRAY_INDICES_ONLY | DUK_ENUM_SORT_ARRAY_INDICES)) {
        /*
         *  Some E5/E5.1 algorithms require that array indices are iterated
         *  in a strictly ascending order.  This is the case for e.g.
         *  Array.prototype.forEach() and JSON.stringify() PropertyList
         *  handling.
         *
         *  To ensure this property for arrays with an array part (and
         *  arbitrary objects too, since e.g. forEach() can be applied
         *  to an array), the caller can request that we sort the keys
         *  here.
         */

        /* FIXME: avoid this at least when target is an Array, it has an
         * array part, and no ancestor properties were included?  Not worth
         * it for JSON, but maybe worth it for forEach().
         */

        /* FIXME: may need a 'length' filter for forEach()
         */
        DUK_DDDPRINT("sort array indices by caller request");
        duk__sort_array_indices(res);
    }

    /* compact; no need to seal because object is internal */
    duk_hobject_compact_props(thr, res);

    DUK_DDDPRINT("created enumerator object: %!iT", duk_get_tval(ctx, -1));
}
void duk_regexp_compile(duk_hthread *thr) {
	duk_context *ctx = (duk_context *) thr;
	duk_re_compiler_ctx re_ctx;
	duk_lexer_point lex_point;
	duk_hstring *h_pattern;
	duk_hstring *h_flags;
	duk_hbuffer_dynamic *h_buffer;

	DUK_ASSERT(thr != NULL);
	DUK_ASSERT(ctx != NULL);

	/*
	 *  Args validation
	 */

	/* TypeError if fails */
	h_pattern = duk_require_hstring(ctx, -2);
	h_flags = duk_require_hstring(ctx, -1);

	/*
	 *  Create normalized 'source' property (E5 Section 15.10.3).
	 */

	/* [ ... pattern flags ] */

	create_escaped_source(thr, -2);

	/* [ ... pattern flags escaped_source ] */

	/*
	 *  Init compilation context
	 */

	duk_push_dynamic_buffer(ctx, 0);
	h_buffer = (duk_hbuffer_dynamic *) duk_require_hbuffer(ctx, -1);
	DUK_ASSERT(DUK_HBUFFER_HAS_DYNAMIC(h_buffer));

	/* [ ... pattern flags escaped_source buffer ] */

	DUK_MEMSET(&re_ctx, 0, sizeof(re_ctx));
	DUK_LEXER_INITCTX(&re_ctx.lex);  /* duplicate zeroing, expect for (possible) NULL inits */
	re_ctx.thr = thr;
	re_ctx.lex.thr = thr;
	re_ctx.lex.input = DUK_HSTRING_GET_DATA(h_pattern);
	re_ctx.lex.input_length = DUK_HSTRING_GET_BYTELEN(h_pattern);
	re_ctx.buf = h_buffer;
	re_ctx.recursion_limit = DUK_RE_COMPILE_RECURSION_LIMIT;
	re_ctx.re_flags = parse_regexp_flags(thr, h_flags);

	DUK_DDPRINT("regexp compiler ctx initialized, flags=0x%08x, recursion_limit=%d",
	            (unsigned int) re_ctx.re_flags, (int) re_ctx.recursion_limit);

	/*
	 *  Init lexer
	 */

	lex_point.offset = 0;		/* expensive init, just want to fill window */
	lex_point.line = 1;
	DUK_LEXER_SETPOINT(&re_ctx.lex, &lex_point);

	/*
	 *  Compilation
	 */

	DUK_DPRINT("starting regexp compilation");

	append_u32(&re_ctx, DUK_REOP_SAVE);
	append_u32(&re_ctx, 0);
	(void) parse_disjunction(&re_ctx, 1);  /* 1 = expect eof */
	append_u32(&re_ctx, DUK_REOP_SAVE);
	append_u32(&re_ctx, 1);
	append_u32(&re_ctx, DUK_REOP_MATCH);

	DUK_DPRINT("regexp bytecode size (before header) is %d bytes",
	           (int) DUK_HBUFFER_GET_SIZE(re_ctx.buf));

	/*
	 *  Check for invalid backreferences; note that it is NOT an error
	 *  to back-reference a capture group which has not yet been introduced
	 *  in the pattern (as in /\1(foo)/); in fact, the backreference will
	 *  always match!  It IS an error to back-reference a capture group
	 *  which will never be introduced in the pattern.  Thus, we can check
	 *  for such references only after parsing is complete.
	 */

	if (re_ctx.highest_backref > re_ctx.captures) {
		DUK_ERROR(thr, DUK_ERR_SYNTAX_ERROR, "invalid backreference(s)");
	}

	/*
	 *  Emit compiled regexp header: flags, ncaptures
	 *  (insertion order inverted on purpose)
	 */

	insert_u32(&re_ctx, 0, (re_ctx.captures + 1) * 2);
	insert_u32(&re_ctx, 0, re_ctx.re_flags);

	DUK_DPRINT("regexp bytecode size (after header) is %d bytes",
	           (int) DUK_HBUFFER_GET_SIZE(re_ctx.buf));
	DUK_DDDPRINT("compiled regexp: %!xO", re_ctx.buf);

	/* [ ... pattern flags escaped_source buffer ] */

	duk_to_string(ctx, -1);  /* coerce to string */

	/* [ ... pattern flags escaped_source bytecode ] */

	/*
	 *  Finalize stack
	 */

	duk_remove(ctx, -4);     /* -> [ ... flags escaped_source bytecode ] */
	duk_remove(ctx, -3);     /* -> [ ... escaped_source bytecode ] */

	DUK_DPRINT("regexp compilation successful, bytecode: %!T, escaped source: %!T",
	           duk_get_tval(ctx, -1), duk_get_tval(ctx, -2));
}