1 /* pb_encode.c -- encode a protobuf using minimal resources
3 * 2011 Petteri Aimonen <jpa@kapsi.fi>
6 #define NANOPB_INTERNALS
10 /* Use the GCC warn_unused_result attribute to check that all return values
11 * are propagated correctly. On other compilers and gcc before 3.4.0 just
12 * ignore the annotation.
14 #if !defined(__GNUC__) || ( __GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
17 #define checkreturn __attribute__((warn_unused_result))
20 /* --- Function pointers to field encoders ---
21 * Order in the array must match pb_action_t LTYPE numbering.
23 typedef bool (*pb_encoder_t)(pb_ostream_t *stream, const pb_field_t *field, const void *src) checkreturn;
24 static const pb_encoder_t PB_ENCODERS[PB_LTYPES_COUNT] = {
36 /*******************************
37 * pb_ostream_t implementation *
38 *******************************/
40 static bool checkreturn buf_write(pb_ostream_t *stream, const uint8_t *buf, size_t count)
42 uint8_t *dest = (uint8_t*)stream->state;
43 stream->state = dest + count;
51 pb_ostream_t pb_ostream_from_buffer(uint8_t *buf, size_t bufsize)
55 stream.callback = (void*)1; /* Just a marker value */
57 stream.callback = &buf_write;
60 stream.max_size = bufsize;
61 stream.bytes_written = 0;
68 bool checkreturn pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count)
70 if (stream->callback != NULL)
72 if (stream->bytes_written + count > stream->max_size)
73 PB_RETURN_ERROR(stream, "stream full");
76 if (!buf_write(stream, buf, count))
77 PB_RETURN_ERROR(stream, "io error");
79 if (!stream->callback(stream, buf, count))
80 PB_RETURN_ERROR(stream, "io error");
84 stream->bytes_written += count;
88 /*************************
89 * Encode a single field *
90 *************************/
92 /* Encode a static array. Handles the size calculations and possible packing. */
93 static bool checkreturn encode_array(pb_ostream_t *stream, const pb_field_t *field,
94 const void *pData, size_t count, pb_encoder_t func)
103 if (count > field->array_size)
104 PB_RETURN_ERROR(stream, "array max size exceeded");
106 /* We always pack arrays if the datatype allows it. */
107 if (PB_LTYPE(field->type) <= PB_LTYPE_LAST_PACKABLE)
109 if (!pb_encode_tag(stream, PB_WT_STRING, field->tag))
112 /* Determine the total size of packed array. */
113 if (PB_LTYPE(field->type) == PB_LTYPE_FIXED32)
117 else if (PB_LTYPE(field->type) == PB_LTYPE_FIXED64)
123 pb_ostream_t sizestream = PB_OSTREAM_SIZING;
125 for (i = 0; i < count; i++)
127 if (!func(&sizestream, field, p))
129 p = (const char*)p + field->data_size;
131 size = sizestream.bytes_written;
134 if (!pb_encode_varint(stream, (uint64_t)size))
137 if (stream->callback == NULL)
138 return pb_write(stream, NULL, size); /* Just sizing.. */
142 for (i = 0; i < count; i++)
144 if (!func(stream, field, p))
146 p = (const char*)p + field->data_size;
152 for (i = 0; i < count; i++)
154 if (!pb_encode_tag_for_field(stream, field))
156 if (!func(stream, field, p))
158 p = (const char*)p + field->data_size;
165 /* Encode a field with static allocation, i.e. one whose data is stored
166 * in the structure itself. */
167 static bool checkreturn encode_static_field(pb_ostream_t *stream,
168 const pb_field_t *field, const void *pData)
174 func = PB_ENCODERS[PB_LTYPE(field->type)];
176 if (field->size_offset)
177 pSize = (const char*)pData + field->size_offset;
181 switch (PB_HTYPE(field->type))
183 case PB_HTYPE_REQUIRED:
184 if (!pb_encode_tag_for_field(stream, field))
186 if (!func(stream, field, pData))
190 case PB_HTYPE_OPTIONAL:
191 if (*(const bool*)pSize)
193 if (!pb_encode_tag_for_field(stream, field))
196 if (!func(stream, field, pData))
201 case PB_HTYPE_REPEATED:
202 if (!encode_array(stream, field, pData, *(const size_t*)pSize, func))
207 PB_RETURN_ERROR(stream, "invalid field type");
213 /* Encode a field with callback semantics. This means that a user function is
214 * called to provide and encode the actual data. */
215 static bool checkreturn encode_callback_field(pb_ostream_t *stream,
216 const pb_field_t *field, const void *pData)
218 const pb_callback_t *callback = (const pb_callback_t*)pData;
220 #ifdef PB_OLD_CALLBACK_STYLE
221 const void *arg = callback->arg;
223 void * const *arg = &(callback->arg);
226 if (callback->funcs.encode != NULL)
228 if (!callback->funcs.encode(stream, field, arg))
229 PB_RETURN_ERROR(stream, "callback error");
234 /* Encode a single field of any callback or static type. */
235 static bool checkreturn encode_field(pb_ostream_t *stream,
236 const pb_field_t *field, const void *pData)
238 switch (PB_ATYPE(field->type))
240 case PB_ATYPE_STATIC:
241 return encode_static_field(stream, field, pData);
243 case PB_ATYPE_CALLBACK:
244 return encode_callback_field(stream, field, pData);
247 PB_RETURN_ERROR(stream, "invalid field type");
251 /* Default handler for extension fields. Expects to have a pb_field_t
252 * pointer in the extension->type->arg field. */
253 static bool checkreturn default_extension_encoder(pb_ostream_t *stream,
254 const pb_extension_t *extension)
256 const pb_field_t *field = (const pb_field_t*)extension->type->arg;
257 return encode_field(stream, field, extension->dest);
260 /* Walk through all the registered extensions and give them a chance
261 * to encode themselves. */
262 static bool checkreturn encode_extension_field(pb_ostream_t *stream,
263 const pb_field_t *field, const void *pData)
265 const pb_extension_t *extension = *(const pb_extension_t* const *)pData;
271 if (extension->type->encode)
272 status = extension->type->encode(stream, extension);
274 status = default_extension_encoder(stream, extension);
279 extension = extension->next;
285 /*********************
286 * Encode all fields *
287 *********************/
289 bool checkreturn pb_encode(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
291 const pb_field_t *field = fields;
292 const void *pData = src_struct;
293 size_t prev_size = 0;
295 while (field->tag != 0)
297 pData = (const char*)pData + prev_size + field->data_offset;
298 prev_size = field->data_size;
300 /* Special case for static arrays */
301 if (PB_ATYPE(field->type) == PB_ATYPE_STATIC &&
302 PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
304 prev_size *= field->array_size;
307 if (PB_LTYPE(field->type) == PB_LTYPE_EXTENSION)
309 /* Special case for the extension field placeholder */
310 if (!encode_extension_field(stream, field, pData))
316 if (!encode_field(stream, field, pData))
326 bool pb_encode_delimited(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
328 return pb_encode_submessage(stream, fields, src_struct);
331 /********************
333 ********************/
334 bool checkreturn pb_encode_varint(pb_ostream_t *stream, uint64_t value)
340 return pb_write(stream, (uint8_t*)&value, 1);
344 buffer[i] = (uint8_t)((value & 0x7F) | 0x80);
348 buffer[i-1] &= 0x7F; /* Unset top bit on last byte */
350 return pb_write(stream, buffer, i);
353 bool checkreturn pb_encode_svarint(pb_ostream_t *stream, int64_t value)
357 zigzagged = (uint64_t)(~(value << 1));
359 zigzagged = (uint64_t)(value << 1);
361 return pb_encode_varint(stream, zigzagged);
364 bool checkreturn pb_encode_fixed32(pb_ostream_t *stream, const void *value)
366 #ifdef __BIG_ENDIAN__
367 const uint8_t *bytes = value;
369 lebytes[0] = bytes[3];
370 lebytes[1] = bytes[2];
371 lebytes[2] = bytes[1];
372 lebytes[3] = bytes[0];
373 return pb_write(stream, lebytes, 4);
375 return pb_write(stream, (const uint8_t*)value, 4);
379 bool checkreturn pb_encode_fixed64(pb_ostream_t *stream, const void *value)
381 #ifdef __BIG_ENDIAN__
382 const uint8_t *bytes = value;
384 lebytes[0] = bytes[7];
385 lebytes[1] = bytes[6];
386 lebytes[2] = bytes[5];
387 lebytes[3] = bytes[4];
388 lebytes[4] = bytes[3];
389 lebytes[5] = bytes[2];
390 lebytes[6] = bytes[1];
391 lebytes[7] = bytes[0];
392 return pb_write(stream, lebytes, 8);
394 return pb_write(stream, (const uint8_t*)value, 8);
398 bool checkreturn pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number)
400 uint64_t tag = wiretype | (field_number << 3);
401 return pb_encode_varint(stream, tag);
404 bool checkreturn pb_encode_tag_for_field(pb_ostream_t *stream, const pb_field_t *field)
406 pb_wire_type_t wiretype;
407 switch (PB_LTYPE(field->type))
409 case PB_LTYPE_VARINT:
410 case PB_LTYPE_SVARINT:
411 wiretype = PB_WT_VARINT;
414 case PB_LTYPE_FIXED32:
415 wiretype = PB_WT_32BIT;
418 case PB_LTYPE_FIXED64:
419 wiretype = PB_WT_64BIT;
423 case PB_LTYPE_STRING:
424 case PB_LTYPE_SUBMESSAGE:
425 wiretype = PB_WT_STRING;
429 PB_RETURN_ERROR(stream, "invalid field type");
432 return pb_encode_tag(stream, wiretype, field->tag);
435 bool checkreturn pb_encode_string(pb_ostream_t *stream, const uint8_t *buffer, size_t size)
437 if (!pb_encode_varint(stream, (uint64_t)size))
440 return pb_write(stream, buffer, size);
443 bool checkreturn pb_encode_submessage(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
445 /* First calculate the message size using a non-writing substream. */
446 pb_ostream_t substream = PB_OSTREAM_SIZING;
450 if (!pb_encode(&substream, fields, src_struct))
453 size = substream.bytes_written;
455 if (!pb_encode_varint(stream, (uint64_t)size))
458 if (stream->callback == NULL)
459 return pb_write(stream, NULL, size); /* Just sizing */
461 if (stream->bytes_written + size > stream->max_size)
462 PB_RETURN_ERROR(stream, "stream full");
464 /* Use a substream to verify that a callback doesn't write more than
465 * what it did the first time. */
466 substream.callback = stream->callback;
467 substream.state = stream->state;
468 substream.max_size = size;
469 substream.bytes_written = 0;
471 substream.errmsg = NULL;
474 status = pb_encode(&substream, fields, src_struct);
476 stream->bytes_written += substream.bytes_written;
477 stream->state = substream.state;
479 stream->errmsg = substream.errmsg;
482 if (substream.bytes_written != size)
483 PB_RETURN_ERROR(stream, "submsg size changed");
490 bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
494 switch (field->data_size)
496 case 1: value = *(const uint8_t*)src; break;
497 case 2: value = *(const uint16_t*)src; break;
498 case 4: value = *(const uint32_t*)src; break;
499 case 8: value = *(const uint64_t*)src; break;
500 default: PB_RETURN_ERROR(stream, "invalid data_size");
503 return pb_encode_varint(stream, value);
506 bool checkreturn pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
510 switch (field->data_size)
512 case 4: value = *(const int32_t*)src; break;
513 case 8: value = *(const int64_t*)src; break;
514 default: PB_RETURN_ERROR(stream, "invalid data_size");
517 return pb_encode_svarint(stream, value);
520 bool checkreturn pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src)
523 return pb_encode_fixed64(stream, src);
526 bool checkreturn pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src)
529 return pb_encode_fixed32(stream, src);
532 bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src)
534 const pb_bytes_array_t *bytes = (const pb_bytes_array_t*)src;
536 if (bytes->size + offsetof(pb_bytes_array_t, bytes) > field->data_size)
537 PB_RETURN_ERROR(stream, "bytes size exceeded");
539 return pb_encode_string(stream, bytes->bytes, bytes->size);
542 bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src)
544 /* strnlen() is not always available, so just use a for-loop */
546 const char *p = (const char*)src;
547 while (size < field->data_size && *p != '\0')
553 return pb_encode_string(stream, (const uint8_t*)src, size);
556 bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src)
558 if (field->ptr == NULL)
559 PB_RETURN_ERROR(stream, "invalid field descriptor");
561 return pb_encode_submessage(stream, (const pb_field_t*)field->ptr, src);