1 /* pb_decode.c -- decode a protobuf using minimal resources
3 * 2011 Petteri Aimonen <jpa@kapsi.fi>
6 /* Use the GCC warn_unused_result attribute to check that all return values
7 * are propagated correctly. On other compilers and gcc before 3.4.0 just
8 * ignore the annotation.
10 #if !defined(__GNUC__) || ( __GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
13 #define checkreturn __attribute__((warn_unused_result))
16 #define NANOPB_INTERNALS
18 #include "pb_decode.h"
20 /**************************************
21 * Declarations internal to this file *
22 **************************************/
24 /* Iterator for pb_field_t list */
26 const pb_field_t *start; /* Start of the pb_field_t array */
27 const pb_field_t *pos; /* Current position of the iterator */
28 unsigned field_index; /* Zero-based index of the field. */
29 unsigned required_field_index; /* Zero-based index that counts only the required fields */
30 void *dest_struct; /* Pointer to the destination structure to decode to */
31 void *pData; /* Pointer where to store current field value */
32 void *pSize; /* Pointer where to store the size of current array field */
33 } pb_field_iterator_t;
35 typedef bool (*pb_decoder_t)(pb_istream_t *stream, const pb_field_t *field, void *dest) checkreturn;
37 static bool checkreturn buf_read(pb_istream_t *stream, uint8_t *buf, size_t count);
38 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest);
39 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size);
40 static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct);
41 static bool pb_field_next(pb_field_iterator_t *iter);
42 static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag);
43 static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
44 static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
45 static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
46 static bool checkreturn default_extension_decoder(pb_istream_t *stream, pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type);
47 static bool checkreturn decode_extension(pb_istream_t *stream, uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
48 static bool checkreturn find_extension_field(pb_field_iterator_t *iter);
49 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct);
50 static bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
51 static bool checkreturn pb_dec_uvarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
52 static bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
53 static bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest);
54 static bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest);
55 static bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
56 static bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
57 static bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
58 static bool checkreturn pb_skip_varint(pb_istream_t *stream);
59 static bool checkreturn pb_skip_string(pb_istream_t *stream);
61 /* --- Function pointers to field decoders ---
62 * Order in the array must match pb_action_t LTYPE numbering.
64 static const pb_decoder_t PB_DECODERS[PB_LTYPES_COUNT] = {
77 /*******************************
78 * pb_istream_t implementation *
79 *******************************/
81 static bool checkreturn buf_read(pb_istream_t *stream, uint8_t *buf, size_t count)
83 uint8_t *source = (uint8_t*)stream->state;
84 stream->state = source + count;
95 bool checkreturn pb_read(pb_istream_t *stream, uint8_t *buf, size_t count)
97 #ifndef PB_BUFFER_ONLY
98 if (buf == NULL && stream->callback != buf_read)
100 /* Skip input bytes */
104 if (!pb_read(stream, tmp, 16))
110 return pb_read(stream, tmp, count);
114 if (stream->bytes_left < count)
115 PB_RETURN_ERROR(stream, "end-of-stream");
117 #ifndef PB_BUFFER_ONLY
118 if (!stream->callback(stream, buf, count))
119 PB_RETURN_ERROR(stream, "io error");
121 if (!buf_read(stream, buf, count))
125 stream->bytes_left -= count;
129 /* Read a single byte from input stream. buf may not be NULL.
130 * This is an optimization for the varint decoding. */
131 static bool checkreturn pb_readbyte(pb_istream_t *stream, uint8_t *buf)
133 if (!stream->bytes_left)
134 PB_RETURN_ERROR(stream, "end-of-stream");
136 #ifndef PB_BUFFER_ONLY
137 if (!stream->callback(stream, buf, 1))
138 PB_RETURN_ERROR(stream, "io error");
140 *buf = *(uint8_t*)stream->state;
141 stream->state = (uint8_t*)stream->state + 1;
144 stream->bytes_left--;
149 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize)
152 #ifdef PB_BUFFER_ONLY
153 stream.callback = NULL;
155 stream.callback = &buf_read;
158 stream.bytes_left = bufsize;
160 stream.errmsg = NULL;
165 /********************
167 ********************/
169 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest)
174 if (!pb_readbyte(stream, &byte))
179 /* Quick case, 1 byte value */
186 result = byte & 0x7F;
191 PB_RETURN_ERROR(stream, "varint overflow");
193 if (!pb_readbyte(stream, &byte))
196 result |= (uint32_t)(byte & 0x7F) << bitpos;
197 bitpos = (uint8_t)(bitpos + 7);
198 } while (byte & 0x80);
205 bool checkreturn pb_decode_varint(pb_istream_t *stream, uint64_t *dest)
214 PB_RETURN_ERROR(stream, "varint overflow");
216 if (!pb_readbyte(stream, &byte))
219 result |= (uint64_t)(byte & 0x7F) << bitpos;
220 bitpos = (uint8_t)(bitpos + 7);
221 } while (byte & 0x80);
227 bool checkreturn pb_skip_varint(pb_istream_t *stream)
232 if (!pb_read(stream, &byte, 1))
234 } while (byte & 0x80);
238 bool checkreturn pb_skip_string(pb_istream_t *stream)
241 if (!pb_decode_varint32(stream, &length))
244 return pb_read(stream, NULL, length);
247 bool checkreturn pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof)
251 *wire_type = (pb_wire_type_t) 0;
254 if (!pb_decode_varint32(stream, &temp))
256 if (stream->bytes_left == 0)
264 *eof = true; /* Special feature: allow 0-terminated messages. */
269 *wire_type = (pb_wire_type_t)(temp & 7);
273 bool checkreturn pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type)
277 case PB_WT_VARINT: return pb_skip_varint(stream);
278 case PB_WT_64BIT: return pb_read(stream, NULL, 8);
279 case PB_WT_STRING: return pb_skip_string(stream);
280 case PB_WT_32BIT: return pb_read(stream, NULL, 4);
281 default: PB_RETURN_ERROR(stream, "invalid wire_type");
285 /* Read a raw value to buffer, for the purpose of passing it to callback as
286 * a substream. Size is maximum size on call, and actual size on return.
288 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size)
290 size_t max_size = *size;
298 if (*size > max_size) return false;
299 if (!pb_read(stream, buf, 1)) return false;
300 } while (*buf++ & 0x80);
305 return pb_read(stream, buf, 8);
309 return pb_read(stream, buf, 4);
311 default: PB_RETURN_ERROR(stream, "invalid wire_type");
315 /* Decode string length from stream and return a substream with limited length.
316 * Remember to close the substream using pb_close_string_substream().
318 bool checkreturn pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream)
321 if (!pb_decode_varint32(stream, &size))
324 *substream = *stream;
325 if (substream->bytes_left < size)
326 PB_RETURN_ERROR(stream, "parent stream too short");
328 substream->bytes_left = size;
329 stream->bytes_left -= size;
333 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream)
335 stream->state = substream->state;
338 stream->errmsg = substream->errmsg;
342 static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct)
344 iter->start = iter->pos = fields;
345 iter->field_index = 0;
346 iter->required_field_index = 0;
347 iter->pData = (char*)dest_struct + iter->pos->data_offset;
348 iter->pSize = (char*)iter->pData + iter->pos->size_offset;
349 iter->dest_struct = dest_struct;
352 static bool pb_field_next(pb_field_iterator_t *iter)
354 bool notwrapped = true;
355 size_t prev_size = iter->pos->data_size;
357 if (PB_ATYPE(iter->pos->type) == PB_ATYPE_STATIC &&
358 PB_HTYPE(iter->pos->type) == PB_HTYPE_REPEATED)
360 prev_size *= iter->pos->array_size;
363 if (iter->pos->tag == 0)
364 return false; /* Only happens with empty message types */
366 if (PB_HTYPE(iter->pos->type) == PB_HTYPE_REQUIRED)
367 iter->required_field_index++;
371 if (iter->pos->tag == 0)
373 iter->pos = iter->start;
374 iter->field_index = 0;
375 iter->required_field_index = 0;
376 iter->pData = iter->dest_struct;
381 iter->pData = (char*)iter->pData + prev_size + iter->pos->data_offset;
382 iter->pSize = (char*)iter->pData + iter->pos->size_offset;
386 static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag)
388 unsigned start = iter->field_index;
391 if (iter->pos->tag == tag &&
392 PB_LTYPE(iter->pos->type) != PB_LTYPE_EXTENSION)
397 } while (iter->field_index != start);
402 /*************************
403 * Decode a single field *
404 *************************/
406 static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
411 type = iter->pos->type;
412 func = PB_DECODERS[PB_LTYPE(type)];
414 switch (PB_HTYPE(type))
416 case PB_HTYPE_REQUIRED:
417 return func(stream, iter->pos, iter->pData);
419 case PB_HTYPE_OPTIONAL:
420 *(bool*)iter->pSize = true;
421 return func(stream, iter->pos, iter->pData);
423 case PB_HTYPE_REPEATED:
424 if (wire_type == PB_WT_STRING
425 && PB_LTYPE(type) <= PB_LTYPE_LAST_PACKABLE)
429 size_t *size = (size_t*)iter->pSize;
430 pb_istream_t substream;
431 if (!pb_make_string_substream(stream, &substream))
434 while (substream.bytes_left && *size < iter->pos->array_size)
436 void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
437 if (!func(&substream, iter->pos, pItem))
444 pb_close_string_substream(stream, &substream);
446 if (substream.bytes_left != 0)
447 PB_RETURN_ERROR(stream, "array overflow");
454 size_t *size = (size_t*)iter->pSize;
455 void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
456 if (*size >= iter->pos->array_size)
457 PB_RETURN_ERROR(stream, "array overflow");
460 return func(stream, iter->pos, pItem);
464 PB_RETURN_ERROR(stream, "invalid field type");
468 static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
470 pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
472 #ifdef PB_OLD_CALLBACK_STYLE
473 void *arg = pCallback->arg;
475 void **arg = &(pCallback->arg);
478 if (pCallback->funcs.decode == NULL)
479 return pb_skip_field(stream, wire_type);
481 if (wire_type == PB_WT_STRING)
483 pb_istream_t substream;
485 if (!pb_make_string_substream(stream, &substream))
490 if (!pCallback->funcs.decode(&substream, iter->pos, arg))
491 PB_RETURN_ERROR(stream, "callback failed");
492 } while (substream.bytes_left);
494 pb_close_string_substream(stream, &substream);
499 /* Copy the single scalar value to stack.
500 * This is required so that we can limit the stream length,
501 * which in turn allows to use same callback for packed and
502 * not-packed fields. */
503 pb_istream_t substream;
505 size_t size = sizeof(buffer);
507 if (!read_raw_value(stream, wire_type, buffer, &size))
509 substream = pb_istream_from_buffer(buffer, size);
511 return pCallback->funcs.decode(&substream, iter->pos, arg);
515 static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
517 switch (PB_ATYPE(iter->pos->type))
519 case PB_ATYPE_STATIC:
520 return decode_static_field(stream, wire_type, iter);
522 case PB_ATYPE_CALLBACK:
523 return decode_callback_field(stream, wire_type, iter);
526 PB_RETURN_ERROR(stream, "invalid field type");
530 /* Default handler for extension fields. Expects a pb_field_t structure
531 * in extension->type->arg. */
532 static bool checkreturn default_extension_decoder(pb_istream_t *stream,
533 pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type)
535 const pb_field_t *field = (const pb_field_t*)extension->type->arg;
536 pb_field_iterator_t iter;
539 if (field->tag != tag)
544 iter.field_index = 0;
545 iter.required_field_index = 0;
546 iter.dest_struct = extension->dest;
547 iter.pData = extension->dest;
550 return decode_field(stream, wire_type, &iter);
553 /* Try to decode an unknown field as an extension field. Tries each extension
554 * decoder in turn, until one of them handles the field or loop ends. */
555 static bool checkreturn decode_extension(pb_istream_t *stream,
556 uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
558 pb_extension_t *extension = *(pb_extension_t* const *)iter->pData;
559 size_t pos = stream->bytes_left;
561 while (extension && pos == stream->bytes_left)
564 if (extension->type->decode)
565 status = extension->type->decode(stream, extension, tag, wire_type);
567 status = default_extension_decoder(stream, extension, tag, wire_type);
572 extension = extension->next;
578 /* Step through the iterator until an extension field is found or until all
579 * entries have been checked. There can be only one extension field per
580 * message. Returns false if no extension field is found. */
581 static bool checkreturn find_extension_field(pb_field_iterator_t *iter)
583 unsigned start = iter->field_index;
586 if (PB_LTYPE(iter->pos->type) == PB_LTYPE_EXTENSION)
589 } while (iter->field_index != start);
594 /* Initialize message fields to default values, recursively */
595 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct)
597 pb_field_iterator_t iter;
598 pb_field_init(&iter, fields, dest_struct);
600 /* Initialize size/has fields and apply default values */
604 type = iter.pos->type;
606 if (iter.pos->tag == 0)
609 if (PB_ATYPE(type) == PB_ATYPE_STATIC)
611 /* Initialize the size field for optional/repeated fields to 0. */
612 if (PB_HTYPE(type) == PB_HTYPE_OPTIONAL)
614 *(bool*)iter.pSize = false;
616 else if (PB_HTYPE(type) == PB_HTYPE_REPEATED)
618 *(size_t*)iter.pSize = 0;
619 continue; /* Array is empty, no need to initialize contents */
622 /* Initialize field contents to default value */
623 if (PB_LTYPE(iter.pos->type) == PB_LTYPE_SUBMESSAGE)
625 pb_message_set_to_defaults((const pb_field_t *) iter.pos->ptr, iter.pData);
627 else if (iter.pos->ptr != NULL)
629 memcpy(iter.pData, iter.pos->ptr, iter.pos->data_size);
633 memset(iter.pData, 0, iter.pos->data_size);
636 else if (PB_ATYPE(type) == PB_ATYPE_CALLBACK)
638 continue; /* Don't overwrite callback */
640 } while (pb_field_next(&iter));
643 /*********************
644 * Decode all fields *
645 *********************/
647 bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
649 uint8_t fields_seen[(PB_MAX_REQUIRED_FIELDS + 7) / 8] = {0}; /* Used to check for required fields */
650 uint32_t extension_range_start = 0;
651 pb_field_iterator_t iter;
653 pb_field_init(&iter, fields, dest_struct);
655 while (stream->bytes_left)
658 pb_wire_type_t wire_type;
661 if (!pb_decode_tag(stream, &wire_type, &tag, &eof))
669 if (!pb_field_find(&iter, tag))
671 /* No match found, check if it matches an extension. */
672 if (tag >= extension_range_start)
674 if (!find_extension_field(&iter))
675 extension_range_start = (uint32_t)-1;
677 extension_range_start = iter.pos->tag;
679 if (tag >= extension_range_start)
681 size_t pos = stream->bytes_left;
683 if (!decode_extension(stream, tag, wire_type, &iter))
686 if (pos != stream->bytes_left)
688 /* The field was handled */
694 /* No match found, skip data */
695 if (!pb_skip_field(stream, wire_type))
700 if (PB_HTYPE(iter.pos->type) == PB_HTYPE_REQUIRED
701 && iter.required_field_index < PB_MAX_REQUIRED_FIELDS)
703 fields_seen[iter.required_field_index >> 3] |= (uint8_t)(1 << (iter.required_field_index & 7));
706 if (!decode_field(stream, wire_type, &iter))
710 /* Check that all required fields were present. */
712 /* First figure out the number of required fields by
713 * seeking to the end of the field array. Usually we
714 * are already close to end after decoding.
716 unsigned req_field_count;
720 req_field_count = iter.required_field_index;
721 last_type = iter.pos->type;
722 } while (pb_field_next(&iter));
724 /* Fixup if last field was also required. */
725 if (PB_HTYPE(last_type) == PB_HTYPE_REQUIRED && iter.pos->tag)
728 /* Check the whole bytes */
729 for (i = 0; i < (req_field_count >> 3); i++)
731 if (fields_seen[i] != 0xFF)
732 PB_RETURN_ERROR(stream, "missing required field");
735 /* Check the remaining bits */
736 if (fields_seen[req_field_count >> 3] != (0xFF >> (8 - (req_field_count & 7))))
737 PB_RETURN_ERROR(stream, "missing required field");
743 bool checkreturn pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
745 pb_message_set_to_defaults(fields, dest_struct);
746 return pb_decode_noinit(stream, fields, dest_struct);
749 bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
751 pb_istream_t substream;
754 if (!pb_make_string_substream(stream, &substream))
757 status = pb_decode(&substream, fields, dest_struct);
758 pb_close_string_substream(stream, &substream);
764 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest)
767 if (!pb_decode_varint(stream, &value))
771 *dest = (int64_t)(~(value >> 1));
773 *dest = (int64_t)(value >> 1);
778 bool pb_decode_fixed32(pb_istream_t *stream, void *dest)
780 #ifdef __BIG_ENDIAN__
781 uint8_t *bytes = (uint8_t*)dest;
784 if (!pb_read(stream, lebytes, 4))
787 bytes[0] = lebytes[3];
788 bytes[1] = lebytes[2];
789 bytes[2] = lebytes[1];
790 bytes[3] = lebytes[0];
793 return pb_read(stream, (uint8_t*)dest, 4);
797 bool pb_decode_fixed64(pb_istream_t *stream, void *dest)
799 #ifdef __BIG_ENDIAN__
800 uint8_t *bytes = (uint8_t*)dest;
803 if (!pb_read(stream, lebytes, 8))
806 bytes[0] = lebytes[7];
807 bytes[1] = lebytes[6];
808 bytes[2] = lebytes[5];
809 bytes[3] = lebytes[4];
810 bytes[4] = lebytes[3];
811 bytes[5] = lebytes[2];
812 bytes[6] = lebytes[1];
813 bytes[7] = lebytes[0];
816 return pb_read(stream, (uint8_t*)dest, 8);
820 bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest)
823 if (!pb_decode_varint(stream, &value))
826 switch (field->data_size)
828 case 1: *(int8_t*)dest = (int8_t)value; break;
829 case 2: *(int16_t*)dest = (int16_t)value; break;
830 case 4: *(int32_t*)dest = (int32_t)value; break;
831 case 8: *(int64_t*)dest = (int64_t)value; break;
832 default: PB_RETURN_ERROR(stream, "invalid data_size");
838 bool checkreturn pb_dec_uvarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
841 if (!pb_decode_varint(stream, &value))
844 switch (field->data_size)
846 case 4: *(uint32_t*)dest = (uint32_t)value; break;
847 case 8: *(uint64_t*)dest = value; break;
848 default: PB_RETURN_ERROR(stream, "invalid data_size");
854 bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
857 if (!pb_decode_svarint(stream, &value))
860 switch (field->data_size)
862 case 4: *(int32_t*)dest = (int32_t)value; break;
863 case 8: *(int64_t*)dest = value; break;
864 default: PB_RETURN_ERROR(stream, "invalid data_size");
870 bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest)
873 return pb_decode_fixed32(stream, dest);
876 bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest)
879 return pb_decode_fixed64(stream, dest);
882 bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
884 pb_bytes_array_t *x = (pb_bytes_array_t*)dest;
887 if (!pb_decode_varint32(stream, &temp))
891 /* Check length, noting the space taken by the size_t header. */
892 if (x->size > field->data_size - offsetof(pb_bytes_array_t, bytes))
893 PB_RETURN_ERROR(stream, "bytes overflow");
895 return pb_read(stream, x->bytes, x->size);
898 bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest)
902 if (!pb_decode_varint32(stream, &size))
905 /* Check length, noting the null terminator */
906 if (size + 1 > field->data_size)
907 PB_RETURN_ERROR(stream, "string overflow");
909 status = pb_read(stream, (uint8_t*)dest, size);
910 *((uint8_t*)dest + size) = 0;
914 bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
917 pb_istream_t substream;
918 const pb_field_t* submsg_fields = (const pb_field_t*)field->ptr;
920 if (!pb_make_string_substream(stream, &substream))
923 if (field->ptr == NULL)
924 PB_RETURN_ERROR(stream, "invalid field descriptor");
926 /* New array entries need to be initialized, while required and optional
927 * submessages have already been initialized in the top-level pb_decode. */
928 if (PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
929 status = pb_decode(&substream, submsg_fields, dest);
931 status = pb_decode_noinit(&substream, submsg_fields, dest);
933 pb_close_string_substream(stream, &substream);