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 if (buf == NULL && stream->callback != buf_read)
57 /* Skip input bytes */
61 if (!pb_read(stream, tmp, 16))
67 return pb_read(stream, tmp, count);
70 if (stream->bytes_left < count)
71 PB_RETURN_ERROR(stream, "end-of-stream");
73 if (!stream->callback(stream, buf, count))
74 PB_RETURN_ERROR(stream, "io error");
76 stream->bytes_left -= count;
80 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize)
83 stream.callback = &buf_read;
85 stream.bytes_left = bufsize;
96 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest)
102 while (bitpos < 32 && pb_read(stream, &byte, 1))
104 *dest |= (uint32_t)(byte & 0x7F) << bitpos;
111 PB_RETURN_ERROR(stream, "varint overflow");
114 bool checkreturn pb_decode_varint(pb_istream_t *stream, uint64_t *dest)
120 while (bitpos < 64 && pb_read(stream, &byte, 1))
122 *dest |= (uint64_t)(byte & 0x7F) << bitpos;
129 PB_RETURN_ERROR(stream, "varint overflow");
132 bool checkreturn pb_skip_varint(pb_istream_t *stream)
137 if (!pb_read(stream, &byte, 1))
139 } while (byte & 0x80);
143 bool checkreturn pb_skip_string(pb_istream_t *stream)
146 if (!pb_decode_varint32(stream, &length))
149 return pb_read(stream, NULL, length);
152 bool checkreturn pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof)
156 *wire_type = (pb_wire_type_t) 0;
159 if (!pb_decode_varint32(stream, &temp))
161 if (stream->bytes_left == 0)
169 *eof = true; /* Special feature: allow 0-terminated messages. */
174 *wire_type = (pb_wire_type_t)(temp & 7);
178 bool checkreturn pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type)
182 case PB_WT_VARINT: return pb_skip_varint(stream);
183 case PB_WT_64BIT: return pb_read(stream, NULL, 8);
184 case PB_WT_STRING: return pb_skip_string(stream);
185 case PB_WT_32BIT: return pb_read(stream, NULL, 4);
186 default: PB_RETURN_ERROR(stream, "invalid wire_type");
190 /* Read a raw value to buffer, for the purpose of passing it to callback as
191 * a substream. Size is maximum size on call, and actual size on return.
193 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size)
195 size_t max_size = *size;
203 if (*size > max_size) return false;
204 if (!pb_read(stream, buf, 1)) return false;
205 } while (*buf++ & 0x80);
210 return pb_read(stream, buf, 8);
214 return pb_read(stream, buf, 4);
216 default: PB_RETURN_ERROR(stream, "invalid wire_type");
220 /* Decode string length from stream and return a substream with limited length.
221 * Remember to close the substream using pb_close_string_substream().
223 bool checkreturn pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream)
226 if (!pb_decode_varint32(stream, &size))
229 *substream = *stream;
230 if (substream->bytes_left < size)
231 PB_RETURN_ERROR(stream, "parent stream too short");
233 substream->bytes_left = size;
234 stream->bytes_left -= size;
238 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream)
240 stream->state = substream->state;
243 stream->errmsg = substream->errmsg;
247 /* Iterator for pb_field_t list */
249 const pb_field_t *start; /* Start of the pb_field_t array */
250 const pb_field_t *current; /* Current position of the iterator */
251 int field_index; /* Zero-based index of the field. */
252 int required_field_index; /* Zero-based index that counts only the required fields */
253 void *dest_struct; /* Pointer to the destination structure to decode to */
254 void *pData; /* Pointer where to store current field value */
255 void *pSize; /* Pointer where to store the size of current array field */
256 } pb_field_iterator_t;
258 static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct)
260 iter->start = iter->current = fields;
261 iter->field_index = 0;
262 iter->required_field_index = 0;
263 iter->pData = (char*)dest_struct + iter->current->data_offset;
264 iter->pSize = (char*)iter->pData + iter->current->size_offset;
265 iter->dest_struct = dest_struct;
268 static bool pb_field_next(pb_field_iterator_t *iter)
270 bool notwrapped = true;
271 size_t prev_size = iter->current->data_size;
273 if (PB_HTYPE(iter->current->type) == PB_HTYPE_ARRAY)
274 prev_size *= iter->current->array_size;
276 if (PB_HTYPE(iter->current->type) == PB_HTYPE_REQUIRED)
277 iter->required_field_index++;
281 if (iter->current->tag == 0)
283 iter->current = iter->start;
284 iter->field_index = 0;
285 iter->required_field_index = 0;
286 iter->pData = iter->dest_struct;
291 iter->pData = (char*)iter->pData + prev_size + iter->current->data_offset;
292 iter->pSize = (char*)iter->pData + iter->current->size_offset;
296 static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag)
298 int start = iter->field_index;
301 if (iter->current->tag == tag)
304 } while (iter->field_index != start);
309 /*************************
310 * Decode a single field *
311 *************************/
313 static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
315 pb_decoder_t func = PB_DECODERS[PB_LTYPE(iter->current->type)];
317 switch (PB_HTYPE(iter->current->type))
319 case PB_HTYPE_REQUIRED:
320 return func(stream, iter->current, iter->pData);
322 case PB_HTYPE_OPTIONAL:
323 *(bool*)iter->pSize = true;
324 return func(stream, iter->current, iter->pData);
327 if (wire_type == PB_WT_STRING
328 && PB_LTYPE(iter->current->type) <= PB_LTYPE_LAST_PACKABLE)
332 size_t *size = (size_t*)iter->pSize;
333 pb_istream_t substream;
334 if (!pb_make_string_substream(stream, &substream))
337 while (substream.bytes_left && *size < iter->current->array_size)
339 void *pItem = (uint8_t*)iter->pData + iter->current->data_size * (*size);
340 if (!func(&substream, iter->current, pItem))
344 status = (substream.bytes_left == 0);
345 pb_close_string_substream(stream, &substream);
351 size_t *size = (size_t*)iter->pSize;
352 void *pItem = (uint8_t*)iter->pData + iter->current->data_size * (*size);
353 if (*size >= iter->current->array_size)
354 PB_RETURN_ERROR(stream, "array overflow");
357 return func(stream, iter->current, pItem);
360 case PB_HTYPE_CALLBACK:
362 pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
364 if (pCallback->funcs.decode == NULL)
365 return pb_skip_field(stream, wire_type);
367 if (wire_type == PB_WT_STRING)
369 pb_istream_t substream;
371 if (!pb_make_string_substream(stream, &substream))
374 while (substream.bytes_left)
376 if (!pCallback->funcs.decode(&substream, iter->current, pCallback->arg))
377 PB_RETURN_ERROR(stream, "callback failed");
380 pb_close_string_substream(stream, &substream);
385 /* Copy the single scalar value to stack.
386 * This is required so that we can limit the stream length,
387 * which in turn allows to use same callback for packed and
388 * not-packed fields. */
389 pb_istream_t substream;
391 size_t size = sizeof(buffer);
393 if (!read_raw_value(stream, wire_type, buffer, &size))
395 substream = pb_istream_from_buffer(buffer, size);
397 return pCallback->funcs.decode(&substream, iter->current, pCallback->arg);
402 PB_RETURN_ERROR(stream, "invalid field type");
406 /* Initialize message fields to default values, recursively */
407 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct)
409 pb_field_iterator_t iter;
410 pb_field_init(&iter, fields, dest_struct);
412 /* Initialize size/has fields and apply default values */
415 if (iter.current->tag == 0)
418 /* Initialize the size field for optional/repeated fields to 0. */
419 if (PB_HTYPE(iter.current->type) == PB_HTYPE_OPTIONAL)
421 *(bool*)iter.pSize = false;
423 else if (PB_HTYPE(iter.current->type) == PB_HTYPE_ARRAY)
425 *(size_t*)iter.pSize = 0;
426 continue; /* Array is empty, no need to initialize contents */
429 /* Initialize field contents to default value */
430 if (PB_HTYPE(iter.current->type) == PB_HTYPE_CALLBACK)
432 continue; /* Don't overwrite callback */
434 else if (PB_LTYPE(iter.current->type) == PB_LTYPE_SUBMESSAGE)
436 pb_message_set_to_defaults((const pb_field_t *) iter.current->ptr, iter.pData);
438 else if (iter.current->ptr != NULL)
440 memcpy(iter.pData, iter.current->ptr, iter.current->data_size);
444 memset(iter.pData, 0, iter.current->data_size);
446 } while (pb_field_next(&iter));
449 /*********************
450 * Decode all fields *
451 *********************/
453 bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
455 uint8_t fields_seen[(PB_MAX_REQUIRED_FIELDS + 7) / 8] = {0}; /* Used to check for required fields */
456 pb_field_iterator_t iter;
458 pb_field_init(&iter, fields, dest_struct);
460 while (stream->bytes_left)
463 pb_wire_type_t wire_type;
466 if (!pb_decode_tag(stream, &wire_type, &tag, &eof))
474 if (!pb_field_find(&iter, tag))
476 /* No match found, skip data */
477 if (!pb_skip_field(stream, wire_type))
482 if (PB_HTYPE(iter.current->type) == PB_HTYPE_REQUIRED
483 && iter.required_field_index < PB_MAX_REQUIRED_FIELDS)
485 fields_seen[iter.required_field_index >> 3] |= (uint8_t)(1 << (iter.required_field_index & 7));
488 if (!decode_field(stream, wire_type, &iter))
492 /* Check that all required fields were present. */
493 pb_field_init(&iter, fields, dest_struct);
495 if (PB_HTYPE(iter.current->type) == PB_HTYPE_REQUIRED &&
496 iter.required_field_index < PB_MAX_REQUIRED_FIELDS &&
497 !(fields_seen[iter.required_field_index >> 3] & (1 << (iter.required_field_index & 7))))
499 PB_RETURN_ERROR(stream, "missing required field");
501 } while (pb_field_next(&iter));
506 bool checkreturn pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
508 pb_message_set_to_defaults(fields, dest_struct);
509 return pb_decode_noinit(stream, fields, dest_struct);
514 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest)
517 if (!pb_decode_varint(stream, &value))
521 *dest = (int64_t)(~(value >> 1));
523 *dest = (int64_t)(value >> 1);
528 bool pb_decode_fixed32(pb_istream_t *stream, void *dest)
530 #ifdef __BIG_ENDIAN__
531 uint8_t *bytes = (uint8_t*)dest;
534 if (!pb_read(stream, lebytes, 4))
537 bytes[0] = lebytes[3];
538 bytes[1] = lebytes[2];
539 bytes[2] = lebytes[1];
540 bytes[3] = lebytes[0];
543 return pb_read(stream, (uint8_t*)dest, 4);
547 bool pb_decode_fixed64(pb_istream_t *stream, void *dest)
549 #ifdef __BIG_ENDIAN__
550 uint8_t *bytes = (uint8_t*)dest;
553 if (!pb_read(stream, lebytes, 8))
556 bytes[0] = lebytes[7];
557 bytes[1] = lebytes[6];
558 bytes[2] = lebytes[5];
559 bytes[3] = lebytes[4];
560 bytes[4] = lebytes[3];
561 bytes[5] = lebytes[2];
562 bytes[6] = lebytes[1];
563 bytes[7] = lebytes[0];
566 return pb_read(stream, (uint8_t*)dest, 8);
570 bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest)
573 bool status = pb_decode_varint(stream, &value);
575 switch (field->data_size)
577 case 1: *(uint8_t*)dest = (uint8_t)value; break;
578 case 2: *(uint16_t*)dest = (uint16_t)value; break;
579 case 4: *(uint32_t*)dest = (uint32_t)value; break;
580 case 8: *(uint64_t*)dest = value; break;
581 default: PB_RETURN_ERROR(stream, "invalid data_size");
587 bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
590 bool status = pb_decode_svarint(stream, &value);
592 switch (field->data_size)
594 case 4: *(int32_t*)dest = (int32_t)value; break;
595 case 8: *(int64_t*)dest = value; break;
596 default: PB_RETURN_ERROR(stream, "invalid data_size");
602 bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest)
605 return pb_decode_fixed32(stream, dest);
608 bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest)
611 return pb_decode_fixed64(stream, dest);
614 bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
616 pb_bytes_array_t *x = (pb_bytes_array_t*)dest;
619 if (!pb_decode_varint32(stream, &temp))
623 /* Check length, noting the space taken by the size_t header. */
624 if (x->size > field->data_size - offsetof(pb_bytes_array_t, bytes))
625 PB_RETURN_ERROR(stream, "bytes overflow");
627 return pb_read(stream, x->bytes, x->size);
630 bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest)
634 if (!pb_decode_varint32(stream, &size))
637 /* Check length, noting the null terminator */
638 if (size + 1 > field->data_size)
639 PB_RETURN_ERROR(stream, "string overflow");
641 status = pb_read(stream, (uint8_t*)dest, size);
642 *((uint8_t*)dest + size) = 0;
646 bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
649 pb_istream_t substream;
650 const pb_field_t* submsg_fields = (const pb_field_t*)field->ptr;
652 if (!pb_make_string_substream(stream, &substream))
655 if (field->ptr == NULL)
656 PB_RETURN_ERROR(stream, "invalid field descriptor");
658 /* New array entries need to be initialized, while required and optional
659 * submessages have already been initialized in the top-level pb_decode. */
660 if (PB_HTYPE(field->type) == PB_HTYPE_ARRAY)
661 status = pb_decode(&substream, submsg_fields, dest);
663 status = pb_decode_noinit(&substream, submsg_fields, dest);
665 pb_close_string_substream(stream, &substream);