1 /* pb_decode.c -- decode a protobuf using minimal resources
3 * 2011 Petteri Aimonen <jpa@kapsi.fi>
6 /* The warn_unused_result attribute appeared first in gcc-3.4.0 */
7 #if !defined(__GNUC__) || ( __GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
10 /* Verify that we remember to check all return values for proper error propagation */
11 #define checkreturn __attribute__((warn_unused_result))
14 #define NANOPB_INTERNALS
16 #include "pb_decode.h"
19 typedef bool (*pb_decoder_t)(pb_istream_t *stream, const pb_field_t *field, void *dest) checkreturn;
21 /* --- Function pointers to field decoders ---
22 * Order in the array must match pb_action_t LTYPE numbering.
24 static const pb_decoder_t PB_DECODERS[PB_LTYPES_COUNT] = {
39 static bool checkreturn buf_read(pb_istream_t *stream, uint8_t *buf, size_t count)
41 uint8_t *source = (uint8_t*)stream->state;
42 stream->state = source + count;
53 bool checkreturn pb_read(pb_istream_t *stream, uint8_t *buf, size_t count)
55 #ifndef PB_BUFFER_ONLY
56 if (buf == NULL && stream->callback != buf_read)
58 /* Skip input bytes */
62 if (!pb_read(stream, tmp, 16))
68 return pb_read(stream, tmp, count);
72 if (stream->bytes_left < count)
73 PB_RETURN_ERROR(stream, "end-of-stream");
75 #ifndef PB_BUFFER_ONLY
76 if (!stream->callback(stream, buf, count))
77 PB_RETURN_ERROR(stream, "io error");
79 if (!buf_read(stream, buf, count))
83 stream->bytes_left -= count;
87 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize)
91 stream.callback = NULL;
93 stream.callback = &buf_read;
96 stream.bytes_left = bufsize;
103 /********************
105 ********************/
107 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest)
113 while (bitpos < 32 && pb_read(stream, &byte, 1))
115 *dest |= (uint32_t)(byte & 0x7F) << bitpos;
122 PB_RETURN_ERROR(stream, "varint overflow");
125 bool checkreturn pb_decode_varint(pb_istream_t *stream, uint64_t *dest)
131 while (bitpos < 64 && pb_read(stream, &byte, 1))
133 *dest |= (uint64_t)(byte & 0x7F) << bitpos;
140 PB_RETURN_ERROR(stream, "varint overflow");
143 bool checkreturn pb_skip_varint(pb_istream_t *stream)
148 if (!pb_read(stream, &byte, 1))
150 } while (byte & 0x80);
154 bool checkreturn pb_skip_string(pb_istream_t *stream)
157 if (!pb_decode_varint32(stream, &length))
160 return pb_read(stream, NULL, length);
163 bool checkreturn pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof)
167 *wire_type = (pb_wire_type_t) 0;
170 if (!pb_decode_varint32(stream, &temp))
172 if (stream->bytes_left == 0)
180 *eof = true; /* Special feature: allow 0-terminated messages. */
185 *wire_type = (pb_wire_type_t)(temp & 7);
189 bool checkreturn pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type)
193 case PB_WT_VARINT: return pb_skip_varint(stream);
194 case PB_WT_64BIT: return pb_read(stream, NULL, 8);
195 case PB_WT_STRING: return pb_skip_string(stream);
196 case PB_WT_32BIT: return pb_read(stream, NULL, 4);
197 default: PB_RETURN_ERROR(stream, "invalid wire_type");
201 /* Read a raw value to buffer, for the purpose of passing it to callback as
202 * a substream. Size is maximum size on call, and actual size on return.
204 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size)
206 size_t max_size = *size;
214 if (*size > max_size) return false;
215 if (!pb_read(stream, buf, 1)) return false;
216 } while (*buf++ & 0x80);
221 return pb_read(stream, buf, 8);
225 return pb_read(stream, buf, 4);
227 default: PB_RETURN_ERROR(stream, "invalid wire_type");
231 /* Decode string length from stream and return a substream with limited length.
232 * Remember to close the substream using pb_close_string_substream().
234 bool checkreturn pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream)
237 if (!pb_decode_varint32(stream, &size))
240 *substream = *stream;
241 if (substream->bytes_left < size)
242 PB_RETURN_ERROR(stream, "parent stream too short");
244 substream->bytes_left = size;
245 stream->bytes_left -= size;
249 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream)
251 stream->state = substream->state;
254 stream->errmsg = substream->errmsg;
258 /* Iterator for pb_field_t list */
260 const pb_field_t *start; /* Start of the pb_field_t array */
261 const pb_field_t *current; /* Current position of the iterator */
262 int field_index; /* Zero-based index of the field. */
263 int required_field_index; /* Zero-based index that counts only the required fields */
264 void *dest_struct; /* Pointer to the destination structure to decode to */
265 void *pData; /* Pointer where to store current field value */
266 void *pSize; /* Pointer where to store the size of current array field */
267 } pb_field_iterator_t;
269 static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct)
271 iter->start = iter->current = fields;
272 iter->field_index = 0;
273 iter->required_field_index = 0;
274 iter->pData = (char*)dest_struct + iter->current->data_offset;
275 iter->pSize = (char*)iter->pData + iter->current->size_offset;
276 iter->dest_struct = dest_struct;
279 static bool pb_field_next(pb_field_iterator_t *iter)
281 bool notwrapped = true;
282 size_t prev_size = iter->current->data_size;
284 if (PB_HTYPE(iter->current->type) == PB_HTYPE_ARRAY)
285 prev_size *= iter->current->array_size;
287 if (PB_HTYPE(iter->current->type) == PB_HTYPE_REQUIRED)
288 iter->required_field_index++;
292 if (iter->current->tag == 0)
294 iter->current = iter->start;
295 iter->field_index = 0;
296 iter->required_field_index = 0;
297 iter->pData = iter->dest_struct;
302 iter->pData = (char*)iter->pData + prev_size + iter->current->data_offset;
303 iter->pSize = (char*)iter->pData + iter->current->size_offset;
307 static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag)
309 int start = iter->field_index;
312 if (iter->current->tag == tag)
315 } while (iter->field_index != start);
320 /*************************
321 * Decode a single field *
322 *************************/
324 static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
326 pb_decoder_t func = PB_DECODERS[PB_LTYPE(iter->current->type)];
328 switch (PB_HTYPE(iter->current->type))
330 case PB_HTYPE_REQUIRED:
331 return func(stream, iter->current, iter->pData);
333 case PB_HTYPE_OPTIONAL:
334 *(bool*)iter->pSize = true;
335 return func(stream, iter->current, iter->pData);
338 if (wire_type == PB_WT_STRING
339 && PB_LTYPE(iter->current->type) <= PB_LTYPE_LAST_PACKABLE)
343 size_t *size = (size_t*)iter->pSize;
344 pb_istream_t substream;
345 if (!pb_make_string_substream(stream, &substream))
348 while (substream.bytes_left && *size < iter->current->array_size)
350 void *pItem = (uint8_t*)iter->pData + iter->current->data_size * (*size);
351 if (!func(&substream, iter->current, pItem))
355 status = (substream.bytes_left == 0);
356 pb_close_string_substream(stream, &substream);
362 size_t *size = (size_t*)iter->pSize;
363 void *pItem = (uint8_t*)iter->pData + iter->current->data_size * (*size);
364 if (*size >= iter->current->array_size)
365 PB_RETURN_ERROR(stream, "array overflow");
368 return func(stream, iter->current, pItem);
371 case PB_HTYPE_CALLBACK:
373 pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
375 if (pCallback->funcs.decode == NULL)
376 return pb_skip_field(stream, wire_type);
378 if (wire_type == PB_WT_STRING)
380 pb_istream_t substream;
382 if (!pb_make_string_substream(stream, &substream))
385 while (substream.bytes_left)
387 if (!pCallback->funcs.decode(&substream, iter->current, pCallback->arg))
388 PB_RETURN_ERROR(stream, "callback failed");
391 pb_close_string_substream(stream, &substream);
396 /* Copy the single scalar value to stack.
397 * This is required so that we can limit the stream length,
398 * which in turn allows to use same callback for packed and
399 * not-packed fields. */
400 pb_istream_t substream;
402 size_t size = sizeof(buffer);
404 if (!read_raw_value(stream, wire_type, buffer, &size))
406 substream = pb_istream_from_buffer(buffer, size);
408 return pCallback->funcs.decode(&substream, iter->current, pCallback->arg);
413 PB_RETURN_ERROR(stream, "invalid field type");
417 /* Initialize message fields to default values, recursively */
418 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct)
420 pb_field_iterator_t iter;
421 pb_field_init(&iter, fields, dest_struct);
423 /* Initialize size/has fields and apply default values */
426 if (iter.current->tag == 0)
429 /* Initialize the size field for optional/repeated fields to 0. */
430 if (PB_HTYPE(iter.current->type) == PB_HTYPE_OPTIONAL)
432 *(bool*)iter.pSize = false;
434 else if (PB_HTYPE(iter.current->type) == PB_HTYPE_ARRAY)
436 *(size_t*)iter.pSize = 0;
437 continue; /* Array is empty, no need to initialize contents */
440 /* Initialize field contents to default value */
441 if (PB_HTYPE(iter.current->type) == PB_HTYPE_CALLBACK)
443 continue; /* Don't overwrite callback */
445 else if (PB_LTYPE(iter.current->type) == PB_LTYPE_SUBMESSAGE)
447 pb_message_set_to_defaults((const pb_field_t *) iter.current->ptr, iter.pData);
449 else if (iter.current->ptr != NULL)
451 memcpy(iter.pData, iter.current->ptr, iter.current->data_size);
455 memset(iter.pData, 0, iter.current->data_size);
457 } while (pb_field_next(&iter));
460 /*********************
461 * Decode all fields *
462 *********************/
464 bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
466 uint8_t fields_seen[(PB_MAX_REQUIRED_FIELDS + 7) / 8] = {0}; /* Used to check for required fields */
467 pb_field_iterator_t iter;
469 pb_field_init(&iter, fields, dest_struct);
471 while (stream->bytes_left)
474 pb_wire_type_t wire_type;
477 if (!pb_decode_tag(stream, &wire_type, &tag, &eof))
485 if (!pb_field_find(&iter, tag))
487 /* No match found, skip data */
488 if (!pb_skip_field(stream, wire_type))
493 if (PB_HTYPE(iter.current->type) == PB_HTYPE_REQUIRED
494 && iter.required_field_index < PB_MAX_REQUIRED_FIELDS)
496 fields_seen[iter.required_field_index >> 3] |= (uint8_t)(1 << (iter.required_field_index & 7));
499 if (!decode_field(stream, wire_type, &iter))
503 /* Check that all required fields were present. */
505 /* First figure out the number of required fields by
506 * seeking to the end of the field array. Usually we
507 * are already close to end after decoding.
513 req_field_count = iter.required_field_index;
514 last_type = iter.current->type;
515 } while (pb_field_next(&iter));
517 /* Fixup if last field was also required. */
518 if (PB_HTYPE(last_type) == PB_HTYPE_REQUIRED)
521 /* Check the whole bytes */
522 for (i = 0; i < (req_field_count >> 3); i++)
524 if (fields_seen[i] != 0xFF)
525 PB_RETURN_ERROR(stream, "missing required field");
528 /* Check the remaining bits */
529 if (fields_seen[req_field_count >> 3] != (0xFF >> (8 - (req_field_count & 7))))
530 PB_RETURN_ERROR(stream, "missing required field");
536 bool checkreturn pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
538 pb_message_set_to_defaults(fields, dest_struct);
539 return pb_decode_noinit(stream, fields, dest_struct);
544 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest)
547 if (!pb_decode_varint(stream, &value))
551 *dest = (int64_t)(~(value >> 1));
553 *dest = (int64_t)(value >> 1);
558 bool pb_decode_fixed32(pb_istream_t *stream, void *dest)
560 #ifdef __BIG_ENDIAN__
561 uint8_t *bytes = (uint8_t*)dest;
564 if (!pb_read(stream, lebytes, 4))
567 bytes[0] = lebytes[3];
568 bytes[1] = lebytes[2];
569 bytes[2] = lebytes[1];
570 bytes[3] = lebytes[0];
573 return pb_read(stream, (uint8_t*)dest, 4);
577 bool pb_decode_fixed64(pb_istream_t *stream, void *dest)
579 #ifdef __BIG_ENDIAN__
580 uint8_t *bytes = (uint8_t*)dest;
583 if (!pb_read(stream, lebytes, 8))
586 bytes[0] = lebytes[7];
587 bytes[1] = lebytes[6];
588 bytes[2] = lebytes[5];
589 bytes[3] = lebytes[4];
590 bytes[4] = lebytes[3];
591 bytes[5] = lebytes[2];
592 bytes[6] = lebytes[1];
593 bytes[7] = lebytes[0];
596 return pb_read(stream, (uint8_t*)dest, 8);
600 bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest)
603 bool status = pb_decode_varint(stream, &value);
605 switch (field->data_size)
607 case 1: *(uint8_t*)dest = (uint8_t)value; break;
608 case 2: *(uint16_t*)dest = (uint16_t)value; break;
609 case 4: *(uint32_t*)dest = (uint32_t)value; break;
610 case 8: *(uint64_t*)dest = value; break;
611 default: PB_RETURN_ERROR(stream, "invalid data_size");
617 bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
620 bool status = pb_decode_svarint(stream, &value);
622 switch (field->data_size)
624 case 4: *(int32_t*)dest = (int32_t)value; break;
625 case 8: *(int64_t*)dest = value; break;
626 default: PB_RETURN_ERROR(stream, "invalid data_size");
632 bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest)
635 return pb_decode_fixed32(stream, dest);
638 bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest)
641 return pb_decode_fixed64(stream, dest);
644 bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
646 pb_bytes_array_t *x = (pb_bytes_array_t*)dest;
649 if (!pb_decode_varint32(stream, &temp))
653 /* Check length, noting the space taken by the size_t header. */
654 if (x->size > field->data_size - offsetof(pb_bytes_array_t, bytes))
655 PB_RETURN_ERROR(stream, "bytes overflow");
657 return pb_read(stream, x->bytes, x->size);
660 bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest)
664 if (!pb_decode_varint32(stream, &size))
667 /* Check length, noting the null terminator */
668 if (size + 1 > field->data_size)
669 PB_RETURN_ERROR(stream, "string overflow");
671 status = pb_read(stream, (uint8_t*)dest, size);
672 *((uint8_t*)dest + size) = 0;
676 bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
679 pb_istream_t substream;
680 const pb_field_t* submsg_fields = (const pb_field_t*)field->ptr;
682 if (!pb_make_string_substream(stream, &substream))
685 if (field->ptr == NULL)
686 PB_RETURN_ERROR(stream, "invalid field descriptor");
688 /* New array entries need to be initialized, while required and optional
689 * submessages have already been initialized in the top-level pb_decode. */
690 if (PB_HTYPE(field->type) == PB_HTYPE_ARRAY)
691 status = pb_decode(&substream, submsg_fields, dest);
693 status = pb_decode_noinit(&substream, submsg_fields, dest);
695 pb_close_string_substream(stream, &substream);