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 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize)
130 #ifdef PB_BUFFER_ONLY
131 stream.callback = NULL;
133 stream.callback = &buf_read;
136 stream.bytes_left = bufsize;
138 stream.errmsg = NULL;
143 /********************
145 ********************/
147 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest)
152 if (!pb_read(stream, &byte, 1))
157 /* Quick case, 1 byte value */
164 result = byte & 0x7F;
169 PB_RETURN_ERROR(stream, "varint overflow");
171 if (!pb_read(stream, &byte, 1))
174 result |= (uint32_t)(byte & 0x7F) << bitpos;
175 bitpos = (uint8_t)(bitpos + 7);
176 } while (byte & 0x80);
183 bool checkreturn pb_decode_varint(pb_istream_t *stream, uint64_t *dest)
192 PB_RETURN_ERROR(stream, "varint overflow");
194 if (!pb_read(stream, &byte, 1))
197 result |= (uint64_t)(byte & 0x7F) << bitpos;
198 bitpos = (uint8_t)(bitpos + 7);
199 } while (byte & 0x80);
205 bool checkreturn pb_skip_varint(pb_istream_t *stream)
210 if (!pb_read(stream, &byte, 1))
212 } while (byte & 0x80);
216 bool checkreturn pb_skip_string(pb_istream_t *stream)
219 if (!pb_decode_varint32(stream, &length))
222 return pb_read(stream, NULL, length);
225 bool checkreturn pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof)
229 *wire_type = (pb_wire_type_t) 0;
232 if (!pb_decode_varint32(stream, &temp))
234 if (stream->bytes_left == 0)
242 *eof = true; /* Special feature: allow 0-terminated messages. */
247 *wire_type = (pb_wire_type_t)(temp & 7);
251 bool checkreturn pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type)
255 case PB_WT_VARINT: return pb_skip_varint(stream);
256 case PB_WT_64BIT: return pb_read(stream, NULL, 8);
257 case PB_WT_STRING: return pb_skip_string(stream);
258 case PB_WT_32BIT: return pb_read(stream, NULL, 4);
259 default: PB_RETURN_ERROR(stream, "invalid wire_type");
263 /* Read a raw value to buffer, for the purpose of passing it to callback as
264 * a substream. Size is maximum size on call, and actual size on return.
266 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size)
268 size_t max_size = *size;
276 if (*size > max_size) return false;
277 if (!pb_read(stream, buf, 1)) return false;
278 } while (*buf++ & 0x80);
283 return pb_read(stream, buf, 8);
287 return pb_read(stream, buf, 4);
289 default: PB_RETURN_ERROR(stream, "invalid wire_type");
293 /* Decode string length from stream and return a substream with limited length.
294 * Remember to close the substream using pb_close_string_substream().
296 bool checkreturn pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream)
299 if (!pb_decode_varint32(stream, &size))
302 *substream = *stream;
303 if (substream->bytes_left < size)
304 PB_RETURN_ERROR(stream, "parent stream too short");
306 substream->bytes_left = size;
307 stream->bytes_left -= size;
311 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream)
313 stream->state = substream->state;
316 stream->errmsg = substream->errmsg;
320 static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct)
322 iter->start = iter->pos = fields;
323 iter->field_index = 0;
324 iter->required_field_index = 0;
325 iter->pData = (char*)dest_struct + iter->pos->data_offset;
326 iter->pSize = (char*)iter->pData + iter->pos->size_offset;
327 iter->dest_struct = dest_struct;
330 static bool pb_field_next(pb_field_iterator_t *iter)
332 bool notwrapped = true;
333 size_t prev_size = iter->pos->data_size;
335 if (PB_ATYPE(iter->pos->type) == PB_ATYPE_STATIC &&
336 PB_HTYPE(iter->pos->type) == PB_HTYPE_REPEATED)
338 prev_size *= iter->pos->array_size;
341 if (iter->pos->tag == 0)
342 return false; /* Only happens with empty message types */
344 if (PB_HTYPE(iter->pos->type) == PB_HTYPE_REQUIRED)
345 iter->required_field_index++;
349 if (iter->pos->tag == 0)
351 iter->pos = iter->start;
352 iter->field_index = 0;
353 iter->required_field_index = 0;
354 iter->pData = iter->dest_struct;
359 iter->pData = (char*)iter->pData + prev_size + iter->pos->data_offset;
360 iter->pSize = (char*)iter->pData + iter->pos->size_offset;
364 static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag)
366 unsigned start = iter->field_index;
369 if (iter->pos->tag == tag &&
370 PB_LTYPE(iter->pos->type) != PB_LTYPE_EXTENSION)
375 } while (iter->field_index != start);
380 /*************************
381 * Decode a single field *
382 *************************/
384 static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
389 type = iter->pos->type;
390 func = PB_DECODERS[PB_LTYPE(type)];
392 switch (PB_HTYPE(type))
394 case PB_HTYPE_REQUIRED:
395 return func(stream, iter->pos, iter->pData);
397 case PB_HTYPE_OPTIONAL:
398 *(bool*)iter->pSize = true;
399 return func(stream, iter->pos, iter->pData);
401 case PB_HTYPE_REPEATED:
402 if (wire_type == PB_WT_STRING
403 && PB_LTYPE(type) <= PB_LTYPE_LAST_PACKABLE)
407 size_t *size = (size_t*)iter->pSize;
408 pb_istream_t substream;
409 if (!pb_make_string_substream(stream, &substream))
412 while (substream.bytes_left && *size < iter->pos->array_size)
414 void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
415 if (!func(&substream, iter->pos, pItem))
422 pb_close_string_substream(stream, &substream);
424 if (substream.bytes_left != 0)
425 PB_RETURN_ERROR(stream, "array overflow");
432 size_t *size = (size_t*)iter->pSize;
433 void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
434 if (*size >= iter->pos->array_size)
435 PB_RETURN_ERROR(stream, "array overflow");
438 return func(stream, iter->pos, pItem);
442 PB_RETURN_ERROR(stream, "invalid field type");
446 static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
448 pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
450 #ifdef PB_OLD_CALLBACK_STYLE
451 void *arg = pCallback->arg;
453 void **arg = &(pCallback->arg);
456 if (pCallback->funcs.decode == NULL)
457 return pb_skip_field(stream, wire_type);
459 if (wire_type == PB_WT_STRING)
461 pb_istream_t substream;
463 if (!pb_make_string_substream(stream, &substream))
468 if (!pCallback->funcs.decode(&substream, iter->pos, arg))
469 PB_RETURN_ERROR(stream, "callback failed");
470 } while (substream.bytes_left);
472 pb_close_string_substream(stream, &substream);
477 /* Copy the single scalar value to stack.
478 * This is required so that we can limit the stream length,
479 * which in turn allows to use same callback for packed and
480 * not-packed fields. */
481 pb_istream_t substream;
483 size_t size = sizeof(buffer);
485 if (!read_raw_value(stream, wire_type, buffer, &size))
487 substream = pb_istream_from_buffer(buffer, size);
489 return pCallback->funcs.decode(&substream, iter->pos, arg);
493 static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
495 switch (PB_ATYPE(iter->pos->type))
497 case PB_ATYPE_STATIC:
498 return decode_static_field(stream, wire_type, iter);
500 case PB_ATYPE_CALLBACK:
501 return decode_callback_field(stream, wire_type, iter);
504 PB_RETURN_ERROR(stream, "invalid field type");
508 /* Default handler for extension fields. Expects a pb_field_t structure
509 * in extension->type->arg. */
510 static bool checkreturn default_extension_decoder(pb_istream_t *stream,
511 pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type)
513 const pb_field_t *field = (const pb_field_t*)extension->type->arg;
514 pb_field_iterator_t iter;
517 if (field->tag != tag)
522 iter.field_index = 0;
523 iter.required_field_index = 0;
524 iter.dest_struct = extension->dest;
525 iter.pData = extension->dest;
528 return decode_field(stream, wire_type, &iter);
531 /* Try to decode an unknown field as an extension field. Tries each extension
532 * decoder in turn, until one of them handles the field or loop ends. */
533 static bool checkreturn decode_extension(pb_istream_t *stream,
534 uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
536 pb_extension_t *extension = *(pb_extension_t* const *)iter->pData;
537 size_t pos = stream->bytes_left;
539 while (extension && pos == stream->bytes_left)
542 if (extension->type->decode)
543 status = extension->type->decode(stream, extension, tag, wire_type);
545 status = default_extension_decoder(stream, extension, tag, wire_type);
550 extension = extension->next;
556 /* Step through the iterator until an extension field is found or until all
557 * entries have been checked. There can be only one extension field per
558 * message. Returns false if no extension field is found. */
559 static bool checkreturn find_extension_field(pb_field_iterator_t *iter)
561 unsigned start = iter->field_index;
564 if (PB_LTYPE(iter->pos->type) == PB_LTYPE_EXTENSION)
567 } while (iter->field_index != start);
572 /* Initialize message fields to default values, recursively */
573 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct)
575 pb_field_iterator_t iter;
576 pb_field_init(&iter, fields, dest_struct);
578 /* Initialize size/has fields and apply default values */
582 type = iter.pos->type;
584 if (iter.pos->tag == 0)
587 if (PB_ATYPE(type) == PB_ATYPE_STATIC)
589 /* Initialize the size field for optional/repeated fields to 0. */
590 if (PB_HTYPE(type) == PB_HTYPE_OPTIONAL)
592 *(bool*)iter.pSize = false;
594 else if (PB_HTYPE(type) == PB_HTYPE_REPEATED)
596 *(size_t*)iter.pSize = 0;
597 continue; /* Array is empty, no need to initialize contents */
600 /* Initialize field contents to default value */
601 if (PB_LTYPE(iter.pos->type) == PB_LTYPE_SUBMESSAGE)
603 pb_message_set_to_defaults((const pb_field_t *) iter.pos->ptr, iter.pData);
605 else if (iter.pos->ptr != NULL)
607 memcpy(iter.pData, iter.pos->ptr, iter.pos->data_size);
611 memset(iter.pData, 0, iter.pos->data_size);
614 else if (PB_ATYPE(type) == PB_ATYPE_CALLBACK)
616 continue; /* Don't overwrite callback */
618 } while (pb_field_next(&iter));
621 /*********************
622 * Decode all fields *
623 *********************/
625 bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
627 uint8_t fields_seen[(PB_MAX_REQUIRED_FIELDS + 7) / 8] = {0}; /* Used to check for required fields */
628 uint32_t extension_range_start = 0;
629 pb_field_iterator_t iter;
631 pb_field_init(&iter, fields, dest_struct);
633 while (stream->bytes_left)
636 pb_wire_type_t wire_type;
639 if (!pb_decode_tag(stream, &wire_type, &tag, &eof))
647 if (!pb_field_find(&iter, tag))
649 /* No match found, check if it matches an extension. */
650 if (tag >= extension_range_start)
652 if (!find_extension_field(&iter))
653 extension_range_start = (uint32_t)-1;
655 extension_range_start = iter.pos->tag;
657 if (tag >= extension_range_start)
659 size_t pos = stream->bytes_left;
661 if (!decode_extension(stream, tag, wire_type, &iter))
664 if (pos != stream->bytes_left)
666 /* The field was handled */
672 /* No match found, skip data */
673 if (!pb_skip_field(stream, wire_type))
678 if (PB_HTYPE(iter.pos->type) == PB_HTYPE_REQUIRED
679 && iter.required_field_index < PB_MAX_REQUIRED_FIELDS)
681 fields_seen[iter.required_field_index >> 3] |= (uint8_t)(1 << (iter.required_field_index & 7));
684 if (!decode_field(stream, wire_type, &iter))
688 /* Check that all required fields were present. */
690 /* First figure out the number of required fields by
691 * seeking to the end of the field array. Usually we
692 * are already close to end after decoding.
694 unsigned req_field_count;
698 req_field_count = iter.required_field_index;
699 last_type = iter.pos->type;
700 } while (pb_field_next(&iter));
702 /* Fixup if last field was also required. */
703 if (PB_HTYPE(last_type) == PB_HTYPE_REQUIRED && iter.pos->tag)
706 /* Check the whole bytes */
707 for (i = 0; i < (req_field_count >> 3); i++)
709 if (fields_seen[i] != 0xFF)
710 PB_RETURN_ERROR(stream, "missing required field");
713 /* Check the remaining bits */
714 if (fields_seen[req_field_count >> 3] != (0xFF >> (8 - (req_field_count & 7))))
715 PB_RETURN_ERROR(stream, "missing required field");
721 bool checkreturn pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
723 pb_message_set_to_defaults(fields, dest_struct);
724 return pb_decode_noinit(stream, fields, dest_struct);
727 bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
729 pb_istream_t substream;
732 if (!pb_make_string_substream(stream, &substream))
735 status = pb_decode(&substream, fields, dest_struct);
736 pb_close_string_substream(stream, &substream);
742 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest)
745 if (!pb_decode_varint(stream, &value))
749 *dest = (int64_t)(~(value >> 1));
751 *dest = (int64_t)(value >> 1);
756 bool pb_decode_fixed32(pb_istream_t *stream, void *dest)
758 #ifdef __BIG_ENDIAN__
759 uint8_t *bytes = (uint8_t*)dest;
762 if (!pb_read(stream, lebytes, 4))
765 bytes[0] = lebytes[3];
766 bytes[1] = lebytes[2];
767 bytes[2] = lebytes[1];
768 bytes[3] = lebytes[0];
771 return pb_read(stream, (uint8_t*)dest, 4);
775 bool pb_decode_fixed64(pb_istream_t *stream, void *dest)
777 #ifdef __BIG_ENDIAN__
778 uint8_t *bytes = (uint8_t*)dest;
781 if (!pb_read(stream, lebytes, 8))
784 bytes[0] = lebytes[7];
785 bytes[1] = lebytes[6];
786 bytes[2] = lebytes[5];
787 bytes[3] = lebytes[4];
788 bytes[4] = lebytes[3];
789 bytes[5] = lebytes[2];
790 bytes[6] = lebytes[1];
791 bytes[7] = lebytes[0];
794 return pb_read(stream, (uint8_t*)dest, 8);
798 bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest)
801 if (!pb_decode_varint(stream, &value))
804 switch (field->data_size)
806 case 1: *(uint8_t*)dest = (uint8_t)value; break;
807 case 2: *(uint16_t*)dest = (uint16_t)value; break;
808 case 4: *(uint32_t*)dest = (uint32_t)value; break;
809 case 8: *(uint64_t*)dest = value; break;
810 default: PB_RETURN_ERROR(stream, "invalid data_size");
816 bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
819 if (!pb_decode_svarint(stream, &value))
822 switch (field->data_size)
824 case 4: *(int32_t*)dest = (int32_t)value; break;
825 case 8: *(int64_t*)dest = value; break;
826 default: PB_RETURN_ERROR(stream, "invalid data_size");
832 bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest)
835 return pb_decode_fixed32(stream, dest);
838 bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest)
841 return pb_decode_fixed64(stream, dest);
844 bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
846 pb_bytes_array_t *x = (pb_bytes_array_t*)dest;
849 if (!pb_decode_varint32(stream, &temp))
853 /* Check length, noting the space taken by the size_t header. */
854 if (x->size > field->data_size - offsetof(pb_bytes_array_t, bytes))
855 PB_RETURN_ERROR(stream, "bytes overflow");
857 return pb_read(stream, x->bytes, x->size);
860 bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest)
864 if (!pb_decode_varint32(stream, &size))
867 /* Check length, noting the null terminator */
868 if (size + 1 > field->data_size)
869 PB_RETURN_ERROR(stream, "string overflow");
871 status = pb_read(stream, (uint8_t*)dest, size);
872 *((uint8_t*)dest + size) = 0;
876 bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
879 pb_istream_t substream;
880 const pb_field_t* submsg_fields = (const pb_field_t*)field->ptr;
882 if (!pb_make_string_substream(stream, &substream))
885 if (field->ptr == NULL)
886 PB_RETURN_ERROR(stream, "invalid field descriptor");
888 /* New array entries need to be initialized, while required and optional
889 * submessages have already been initialized in the top-level pb_decode. */
890 if (PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
891 status = pb_decode(&substream, submsg_fields, dest);
893 status = pb_decode_noinit(&substream, submsg_fields, dest);
895 pb_close_string_substream(stream, &substream);