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 pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
51 static bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
52 static bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest);
53 static bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest);
54 static bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
55 static bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
56 static bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
57 static bool checkreturn pb_skip_varint(pb_istream_t *stream);
58 static bool checkreturn pb_skip_string(pb_istream_t *stream);
60 /* --- Function pointers to field decoders ---
61 * Order in the array must match pb_action_t LTYPE numbering.
63 static const pb_decoder_t PB_DECODERS[PB_LTYPES_COUNT] = {
75 /*******************************
76 * pb_istream_t implementation *
77 *******************************/
79 static bool checkreturn buf_read(pb_istream_t *stream, uint8_t *buf, size_t count)
81 uint8_t *source = (uint8_t*)stream->state;
82 stream->state = source + count;
93 bool checkreturn pb_read(pb_istream_t *stream, uint8_t *buf, size_t count)
95 #ifndef PB_BUFFER_ONLY
96 if (buf == NULL && stream->callback != buf_read)
98 /* Skip input bytes */
102 if (!pb_read(stream, tmp, 16))
108 return pb_read(stream, tmp, count);
112 if (stream->bytes_left < count)
113 PB_RETURN_ERROR(stream, "end-of-stream");
115 #ifndef PB_BUFFER_ONLY
116 if (!stream->callback(stream, buf, count))
117 PB_RETURN_ERROR(stream, "io error");
119 if (!buf_read(stream, buf, count))
123 stream->bytes_left -= count;
127 /* Read a single byte from input stream. buf may not be NULL.
128 * This is an optimization for the varint decoding. */
129 static bool checkreturn pb_readbyte(pb_istream_t *stream, uint8_t *buf)
131 if (!stream->bytes_left)
132 PB_RETURN_ERROR(stream, "end-of-stream");
134 #ifndef PB_BUFFER_ONLY
135 if (!stream->callback(stream, buf, 1))
136 PB_RETURN_ERROR(stream, "io error");
138 *buf = *(uint8_t*)stream->state;
139 stream->state = (uint8_t*)stream->state + 1;
142 stream->bytes_left--;
147 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize)
150 #ifdef PB_BUFFER_ONLY
151 stream.callback = NULL;
153 stream.callback = &buf_read;
156 stream.bytes_left = bufsize;
158 stream.errmsg = NULL;
163 /********************
165 ********************/
167 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest)
172 if (!pb_readbyte(stream, &byte))
177 /* Quick case, 1 byte value */
184 result = byte & 0x7F;
189 PB_RETURN_ERROR(stream, "varint overflow");
191 if (!pb_readbyte(stream, &byte))
194 result |= (uint32_t)(byte & 0x7F) << bitpos;
195 bitpos = (uint8_t)(bitpos + 7);
196 } while (byte & 0x80);
203 bool checkreturn pb_decode_varint(pb_istream_t *stream, uint64_t *dest)
212 PB_RETURN_ERROR(stream, "varint overflow");
214 if (!pb_readbyte(stream, &byte))
217 result |= (uint64_t)(byte & 0x7F) << bitpos;
218 bitpos = (uint8_t)(bitpos + 7);
219 } while (byte & 0x80);
225 bool checkreturn pb_skip_varint(pb_istream_t *stream)
230 if (!pb_read(stream, &byte, 1))
232 } while (byte & 0x80);
236 bool checkreturn pb_skip_string(pb_istream_t *stream)
239 if (!pb_decode_varint32(stream, &length))
242 return pb_read(stream, NULL, length);
245 bool checkreturn pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof)
249 *wire_type = (pb_wire_type_t) 0;
252 if (!pb_decode_varint32(stream, &temp))
254 if (stream->bytes_left == 0)
262 *eof = true; /* Special feature: allow 0-terminated messages. */
267 *wire_type = (pb_wire_type_t)(temp & 7);
271 bool checkreturn pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type)
275 case PB_WT_VARINT: return pb_skip_varint(stream);
276 case PB_WT_64BIT: return pb_read(stream, NULL, 8);
277 case PB_WT_STRING: return pb_skip_string(stream);
278 case PB_WT_32BIT: return pb_read(stream, NULL, 4);
279 default: PB_RETURN_ERROR(stream, "invalid wire_type");
283 /* Read a raw value to buffer, for the purpose of passing it to callback as
284 * a substream. Size is maximum size on call, and actual size on return.
286 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size)
288 size_t max_size = *size;
296 if (*size > max_size) return false;
297 if (!pb_read(stream, buf, 1)) return false;
298 } while (*buf++ & 0x80);
303 return pb_read(stream, buf, 8);
307 return pb_read(stream, buf, 4);
309 default: PB_RETURN_ERROR(stream, "invalid wire_type");
313 /* Decode string length from stream and return a substream with limited length.
314 * Remember to close the substream using pb_close_string_substream().
316 bool checkreturn pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream)
319 if (!pb_decode_varint32(stream, &size))
322 *substream = *stream;
323 if (substream->bytes_left < size)
324 PB_RETURN_ERROR(stream, "parent stream too short");
326 substream->bytes_left = size;
327 stream->bytes_left -= size;
331 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream)
333 stream->state = substream->state;
336 stream->errmsg = substream->errmsg;
340 static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct)
342 iter->start = iter->pos = fields;
343 iter->field_index = 0;
344 iter->required_field_index = 0;
345 iter->pData = (char*)dest_struct + iter->pos->data_offset;
346 iter->pSize = (char*)iter->pData + iter->pos->size_offset;
347 iter->dest_struct = dest_struct;
350 static bool pb_field_next(pb_field_iterator_t *iter)
352 bool notwrapped = true;
353 size_t prev_size = iter->pos->data_size;
355 if (PB_ATYPE(iter->pos->type) == PB_ATYPE_STATIC &&
356 PB_HTYPE(iter->pos->type) == PB_HTYPE_REPEATED)
358 prev_size *= iter->pos->array_size;
361 if (iter->pos->tag == 0)
362 return false; /* Only happens with empty message types */
364 if (PB_HTYPE(iter->pos->type) == PB_HTYPE_REQUIRED)
365 iter->required_field_index++;
369 if (iter->pos->tag == 0)
371 iter->pos = iter->start;
372 iter->field_index = 0;
373 iter->required_field_index = 0;
374 iter->pData = iter->dest_struct;
379 iter->pData = (char*)iter->pData + prev_size + iter->pos->data_offset;
380 iter->pSize = (char*)iter->pData + iter->pos->size_offset;
384 static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag)
386 unsigned start = iter->field_index;
389 if (iter->pos->tag == tag &&
390 PB_LTYPE(iter->pos->type) != PB_LTYPE_EXTENSION)
395 } while (iter->field_index != start);
400 /*************************
401 * Decode a single field *
402 *************************/
404 static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
409 type = iter->pos->type;
410 func = PB_DECODERS[PB_LTYPE(type)];
412 switch (PB_HTYPE(type))
414 case PB_HTYPE_REQUIRED:
415 return func(stream, iter->pos, iter->pData);
417 case PB_HTYPE_OPTIONAL:
418 *(bool*)iter->pSize = true;
419 return func(stream, iter->pos, iter->pData);
421 case PB_HTYPE_REPEATED:
422 if (wire_type == PB_WT_STRING
423 && PB_LTYPE(type) <= PB_LTYPE_LAST_PACKABLE)
427 size_t *size = (size_t*)iter->pSize;
428 pb_istream_t substream;
429 if (!pb_make_string_substream(stream, &substream))
432 while (substream.bytes_left && *size < iter->pos->array_size)
434 void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
435 if (!func(&substream, iter->pos, pItem))
442 pb_close_string_substream(stream, &substream);
444 if (substream.bytes_left != 0)
445 PB_RETURN_ERROR(stream, "array overflow");
452 size_t *size = (size_t*)iter->pSize;
453 void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
454 if (*size >= iter->pos->array_size)
455 PB_RETURN_ERROR(stream, "array overflow");
458 return func(stream, iter->pos, pItem);
462 PB_RETURN_ERROR(stream, "invalid field type");
466 static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
468 pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
470 #ifdef PB_OLD_CALLBACK_STYLE
471 void *arg = pCallback->arg;
473 void **arg = &(pCallback->arg);
476 if (pCallback->funcs.decode == NULL)
477 return pb_skip_field(stream, wire_type);
479 if (wire_type == PB_WT_STRING)
481 pb_istream_t substream;
483 if (!pb_make_string_substream(stream, &substream))
488 if (!pCallback->funcs.decode(&substream, iter->pos, arg))
489 PB_RETURN_ERROR(stream, "callback failed");
490 } while (substream.bytes_left);
492 pb_close_string_substream(stream, &substream);
497 /* Copy the single scalar value to stack.
498 * This is required so that we can limit the stream length,
499 * which in turn allows to use same callback for packed and
500 * not-packed fields. */
501 pb_istream_t substream;
503 size_t size = sizeof(buffer);
505 if (!read_raw_value(stream, wire_type, buffer, &size))
507 substream = pb_istream_from_buffer(buffer, size);
509 return pCallback->funcs.decode(&substream, iter->pos, arg);
513 static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
515 switch (PB_ATYPE(iter->pos->type))
517 case PB_ATYPE_STATIC:
518 return decode_static_field(stream, wire_type, iter);
520 case PB_ATYPE_CALLBACK:
521 return decode_callback_field(stream, wire_type, iter);
524 PB_RETURN_ERROR(stream, "invalid field type");
528 /* Default handler for extension fields. Expects a pb_field_t structure
529 * in extension->type->arg. */
530 static bool checkreturn default_extension_decoder(pb_istream_t *stream,
531 pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type)
533 const pb_field_t *field = (const pb_field_t*)extension->type->arg;
534 pb_field_iterator_t iter;
537 if (field->tag != tag)
542 iter.field_index = 0;
543 iter.required_field_index = 0;
544 iter.dest_struct = extension->dest;
545 iter.pData = extension->dest;
548 return decode_field(stream, wire_type, &iter);
551 /* Try to decode an unknown field as an extension field. Tries each extension
552 * decoder in turn, until one of them handles the field or loop ends. */
553 static bool checkreturn decode_extension(pb_istream_t *stream,
554 uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
556 pb_extension_t *extension = *(pb_extension_t* const *)iter->pData;
557 size_t pos = stream->bytes_left;
559 while (extension && pos == stream->bytes_left)
562 if (extension->type->decode)
563 status = extension->type->decode(stream, extension, tag, wire_type);
565 status = default_extension_decoder(stream, extension, tag, wire_type);
570 extension = extension->next;
576 /* Step through the iterator until an extension field is found or until all
577 * entries have been checked. There can be only one extension field per
578 * message. Returns false if no extension field is found. */
579 static bool checkreturn find_extension_field(pb_field_iterator_t *iter)
581 unsigned start = iter->field_index;
584 if (PB_LTYPE(iter->pos->type) == PB_LTYPE_EXTENSION)
587 } while (iter->field_index != start);
592 /* Initialize message fields to default values, recursively */
593 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct)
595 pb_field_iterator_t iter;
596 pb_field_init(&iter, fields, dest_struct);
598 /* Initialize size/has fields and apply default values */
602 type = iter.pos->type;
604 if (iter.pos->tag == 0)
607 if (PB_ATYPE(type) == PB_ATYPE_STATIC)
609 /* Initialize the size field for optional/repeated fields to 0. */
610 if (PB_HTYPE(type) == PB_HTYPE_OPTIONAL)
612 *(bool*)iter.pSize = false;
614 else if (PB_HTYPE(type) == PB_HTYPE_REPEATED)
616 *(size_t*)iter.pSize = 0;
617 continue; /* Array is empty, no need to initialize contents */
620 /* Initialize field contents to default value */
621 if (PB_LTYPE(iter.pos->type) == PB_LTYPE_SUBMESSAGE)
623 pb_message_set_to_defaults((const pb_field_t *) iter.pos->ptr, iter.pData);
625 else if (iter.pos->ptr != NULL)
627 memcpy(iter.pData, iter.pos->ptr, iter.pos->data_size);
631 memset(iter.pData, 0, iter.pos->data_size);
634 else if (PB_ATYPE(type) == PB_ATYPE_CALLBACK)
636 continue; /* Don't overwrite callback */
638 } while (pb_field_next(&iter));
641 /*********************
642 * Decode all fields *
643 *********************/
645 bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
647 uint8_t fields_seen[(PB_MAX_REQUIRED_FIELDS + 7) / 8] = {0}; /* Used to check for required fields */
648 uint32_t extension_range_start = 0;
649 pb_field_iterator_t iter;
651 pb_field_init(&iter, fields, dest_struct);
653 while (stream->bytes_left)
656 pb_wire_type_t wire_type;
659 if (!pb_decode_tag(stream, &wire_type, &tag, &eof))
667 if (!pb_field_find(&iter, tag))
669 /* No match found, check if it matches an extension. */
670 if (tag >= extension_range_start)
672 if (!find_extension_field(&iter))
673 extension_range_start = (uint32_t)-1;
675 extension_range_start = iter.pos->tag;
677 if (tag >= extension_range_start)
679 size_t pos = stream->bytes_left;
681 if (!decode_extension(stream, tag, wire_type, &iter))
684 if (pos != stream->bytes_left)
686 /* The field was handled */
692 /* No match found, skip data */
693 if (!pb_skip_field(stream, wire_type))
698 if (PB_HTYPE(iter.pos->type) == PB_HTYPE_REQUIRED
699 && iter.required_field_index < PB_MAX_REQUIRED_FIELDS)
701 fields_seen[iter.required_field_index >> 3] |= (uint8_t)(1 << (iter.required_field_index & 7));
704 if (!decode_field(stream, wire_type, &iter))
708 /* Check that all required fields were present. */
710 /* First figure out the number of required fields by
711 * seeking to the end of the field array. Usually we
712 * are already close to end after decoding.
714 unsigned req_field_count;
718 req_field_count = iter.required_field_index;
719 last_type = iter.pos->type;
720 } while (pb_field_next(&iter));
722 /* Fixup if last field was also required. */
723 if (PB_HTYPE(last_type) == PB_HTYPE_REQUIRED && iter.pos->tag)
726 /* Check the whole bytes */
727 for (i = 0; i < (req_field_count >> 3); i++)
729 if (fields_seen[i] != 0xFF)
730 PB_RETURN_ERROR(stream, "missing required field");
733 /* Check the remaining bits */
734 if (fields_seen[req_field_count >> 3] != (0xFF >> (8 - (req_field_count & 7))))
735 PB_RETURN_ERROR(stream, "missing required field");
741 bool checkreturn pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
743 pb_message_set_to_defaults(fields, dest_struct);
744 return pb_decode_noinit(stream, fields, dest_struct);
747 bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
749 pb_istream_t substream;
752 if (!pb_make_string_substream(stream, &substream))
755 status = pb_decode(&substream, fields, dest_struct);
756 pb_close_string_substream(stream, &substream);
762 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest)
765 if (!pb_decode_varint(stream, &value))
769 *dest = (int64_t)(~(value >> 1));
771 *dest = (int64_t)(value >> 1);
776 bool pb_decode_fixed32(pb_istream_t *stream, void *dest)
778 #ifdef __BIG_ENDIAN__
779 uint8_t *bytes = (uint8_t*)dest;
782 if (!pb_read(stream, lebytes, 4))
785 bytes[0] = lebytes[3];
786 bytes[1] = lebytes[2];
787 bytes[2] = lebytes[1];
788 bytes[3] = lebytes[0];
791 return pb_read(stream, (uint8_t*)dest, 4);
795 bool pb_decode_fixed64(pb_istream_t *stream, void *dest)
797 #ifdef __BIG_ENDIAN__
798 uint8_t *bytes = (uint8_t*)dest;
801 if (!pb_read(stream, lebytes, 8))
804 bytes[0] = lebytes[7];
805 bytes[1] = lebytes[6];
806 bytes[2] = lebytes[5];
807 bytes[3] = lebytes[4];
808 bytes[4] = lebytes[3];
809 bytes[5] = lebytes[2];
810 bytes[6] = lebytes[1];
811 bytes[7] = lebytes[0];
814 return pb_read(stream, (uint8_t*)dest, 8);
818 bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest)
821 if (!pb_decode_varint(stream, &value))
824 switch (field->data_size)
826 case 1: *(uint8_t*)dest = (uint8_t)value; break;
827 case 2: *(uint16_t*)dest = (uint16_t)value; break;
828 case 4: *(uint32_t*)dest = (uint32_t)value; break;
829 case 8: *(uint64_t*)dest = value; break;
830 default: PB_RETURN_ERROR(stream, "invalid data_size");
836 bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
839 if (!pb_decode_svarint(stream, &value))
842 switch (field->data_size)
844 case 4: *(int32_t*)dest = (int32_t)value; break;
845 case 8: *(int64_t*)dest = value; break;
846 default: PB_RETURN_ERROR(stream, "invalid data_size");
852 bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest)
855 return pb_decode_fixed32(stream, dest);
858 bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest)
861 return pb_decode_fixed64(stream, dest);
864 bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
866 pb_bytes_array_t *x = (pb_bytes_array_t*)dest;
869 if (!pb_decode_varint32(stream, &temp))
873 /* Check length, noting the space taken by the size_t header. */
874 if (x->size > field->data_size - offsetof(pb_bytes_array_t, bytes))
875 PB_RETURN_ERROR(stream, "bytes overflow");
877 return pb_read(stream, x->bytes, x->size);
880 bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest)
884 if (!pb_decode_varint32(stream, &size))
887 /* Check length, noting the null terminator */
888 if (size + 1 > field->data_size)
889 PB_RETURN_ERROR(stream, "string overflow");
891 status = pb_read(stream, (uint8_t*)dest, size);
892 *((uint8_t*)dest + size) = 0;
896 bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
899 pb_istream_t substream;
900 const pb_field_t* submsg_fields = (const pb_field_t*)field->ptr;
902 if (!pb_make_string_substream(stream, &substream))
905 if (field->ptr == NULL)
906 PB_RETURN_ERROR(stream, "invalid field descriptor");
908 /* New array entries need to be initialized, while required and optional
909 * submessages have already been initialized in the top-level pb_decode. */
910 if (PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
911 status = pb_decode(&substream, submsg_fields, dest);
913 status = pb_decode_noinit(&substream, submsg_fields, dest);
915 pb_close_string_substream(stream, &substream);