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 /**************************************
21 * Declarations internal to this file *
22 **************************************/
23 typedef bool (*pb_encoder_t)(pb_ostream_t *stream, const pb_field_t *field, const void *src) checkreturn;
25 static bool checkreturn buf_write(pb_ostream_t *stream, const uint8_t *buf, size_t count);
26 static bool checkreturn encode_array(pb_ostream_t *stream, const pb_field_t *field, const void *pData, size_t count, pb_encoder_t func);
27 static bool checkreturn encode_field(pb_ostream_t *stream, const pb_field_t *field, const void *pData);
28 static bool checkreturn default_extension_encoder(pb_ostream_t *stream, const pb_extension_t *extension);
29 static bool checkreturn encode_extension_field(pb_ostream_t *stream, const pb_field_t *field, const void *pData);
30 static bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
31 static bool checkreturn pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
32 static bool checkreturn pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src);
33 static bool checkreturn pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src);
34 static bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src);
35 static bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src);
36 static bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src);
38 /* --- Function pointers to field encoders ---
39 * Order in the array must match pb_action_t LTYPE numbering.
41 static const pb_encoder_t PB_ENCODERS[PB_LTYPES_COUNT] = {
53 /*******************************
54 * pb_ostream_t implementation *
55 *******************************/
57 static bool checkreturn buf_write(pb_ostream_t *stream, const uint8_t *buf, size_t count)
59 uint8_t *dest = (uint8_t*)stream->state;
60 stream->state = dest + count;
68 pb_ostream_t pb_ostream_from_buffer(uint8_t *buf, size_t bufsize)
72 stream.callback = (void*)1; /* Just a marker value */
74 stream.callback = &buf_write;
77 stream.max_size = bufsize;
78 stream.bytes_written = 0;
85 bool checkreturn pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count)
87 if (stream->callback != NULL)
89 if (stream->bytes_written + count > stream->max_size)
90 PB_RETURN_ERROR(stream, "stream full");
93 if (!buf_write(stream, buf, count))
94 PB_RETURN_ERROR(stream, "io error");
96 if (!stream->callback(stream, buf, count))
97 PB_RETURN_ERROR(stream, "io error");
101 stream->bytes_written += count;
105 /*************************
106 * Encode a single field *
107 *************************/
109 /* Encode a static array. Handles the size calculations and possible packing. */
110 static bool checkreturn encode_array(pb_ostream_t *stream, const pb_field_t *field,
111 const void *pData, size_t count, pb_encoder_t func)
120 if (count > field->array_size)
121 PB_RETURN_ERROR(stream, "array max size exceeded");
123 /* We always pack arrays if the datatype allows it. */
124 if (PB_LTYPE(field->type) <= PB_LTYPE_LAST_PACKABLE)
126 if (!pb_encode_tag(stream, PB_WT_STRING, field->tag))
129 /* Determine the total size of packed array. */
130 if (PB_LTYPE(field->type) == PB_LTYPE_FIXED32)
134 else if (PB_LTYPE(field->type) == PB_LTYPE_FIXED64)
140 pb_ostream_t sizestream = PB_OSTREAM_SIZING;
142 for (i = 0; i < count; i++)
144 if (!func(&sizestream, field, p))
146 p = (const char*)p + field->data_size;
148 size = sizestream.bytes_written;
151 if (!pb_encode_varint(stream, (uint64_t)size))
154 if (stream->callback == NULL)
155 return pb_write(stream, NULL, size); /* Just sizing.. */
159 for (i = 0; i < count; i++)
161 if (!func(stream, field, p))
163 p = (const char*)p + field->data_size;
169 for (i = 0; i < count; i++)
171 if (!pb_encode_tag_for_field(stream, field))
173 if (!func(stream, field, p))
175 p = (const char*)p + field->data_size;
182 /* Encode a field with static allocation, i.e. one whose data is stored
183 * in the structure itself. */
184 static bool checkreturn encode_static_field(pb_ostream_t *stream,
185 const pb_field_t *field, const void *pData)
191 func = PB_ENCODERS[PB_LTYPE(field->type)];
193 if (field->size_offset)
194 pSize = (const char*)pData + field->size_offset;
198 switch (PB_HTYPE(field->type))
200 case PB_HTYPE_REQUIRED:
201 if (!pb_encode_tag_for_field(stream, field))
203 if (!func(stream, field, pData))
207 case PB_HTYPE_OPTIONAL:
208 if (*(const bool*)pSize)
210 if (!pb_encode_tag_for_field(stream, field))
213 if (!func(stream, field, pData))
218 case PB_HTYPE_REPEATED:
219 if (!encode_array(stream, field, pData, *(const size_t*)pSize, func))
224 PB_RETURN_ERROR(stream, "invalid field type");
230 /* Encode a field with callback semantics. This means that a user function is
231 * called to provide and encode the actual data. */
232 static bool checkreturn encode_callback_field(pb_ostream_t *stream,
233 const pb_field_t *field, const void *pData)
235 const pb_callback_t *callback = (const pb_callback_t*)pData;
237 #ifdef PB_OLD_CALLBACK_STYLE
238 const void *arg = callback->arg;
240 void * const *arg = &(callback->arg);
243 if (callback->funcs.encode != NULL)
245 if (!callback->funcs.encode(stream, field, arg))
246 PB_RETURN_ERROR(stream, "callback error");
251 /* Encode a single field of any callback or static type. */
252 static bool checkreturn encode_field(pb_ostream_t *stream,
253 const pb_field_t *field, const void *pData)
255 switch (PB_ATYPE(field->type))
257 case PB_ATYPE_STATIC:
258 return encode_static_field(stream, field, pData);
260 case PB_ATYPE_CALLBACK:
261 return encode_callback_field(stream, field, pData);
264 PB_RETURN_ERROR(stream, "invalid field type");
268 /* Default handler for extension fields. Expects to have a pb_field_t
269 * pointer in the extension->type->arg field. */
270 static bool checkreturn default_extension_encoder(pb_ostream_t *stream,
271 const pb_extension_t *extension)
273 const pb_field_t *field = (const pb_field_t*)extension->type->arg;
274 return encode_field(stream, field, extension->dest);
277 /* Walk through all the registered extensions and give them a chance
278 * to encode themselves. */
279 static bool checkreturn encode_extension_field(pb_ostream_t *stream,
280 const pb_field_t *field, const void *pData)
282 const pb_extension_t *extension = *(const pb_extension_t* const *)pData;
288 if (extension->type->encode)
289 status = extension->type->encode(stream, extension);
291 status = default_extension_encoder(stream, extension);
296 extension = extension->next;
302 /*********************
303 * Encode all fields *
304 *********************/
306 bool checkreturn pb_encode(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
308 const pb_field_t *field = fields;
309 const void *pData = src_struct;
310 size_t prev_size = 0;
312 while (field->tag != 0)
314 pData = (const char*)pData + prev_size + field->data_offset;
315 prev_size = field->data_size;
317 /* Special case for static arrays */
318 if (PB_ATYPE(field->type) == PB_ATYPE_STATIC &&
319 PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
321 prev_size *= field->array_size;
324 if (PB_LTYPE(field->type) == PB_LTYPE_EXTENSION)
326 /* Special case for the extension field placeholder */
327 if (!encode_extension_field(stream, field, pData))
333 if (!encode_field(stream, field, pData))
343 bool pb_encode_delimited(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
345 return pb_encode_submessage(stream, fields, src_struct);
348 /********************
350 ********************/
351 bool checkreturn pb_encode_varint(pb_ostream_t *stream, uint64_t value)
357 return pb_write(stream, (uint8_t*)&value, 1);
361 buffer[i] = (uint8_t)((value & 0x7F) | 0x80);
365 buffer[i-1] &= 0x7F; /* Unset top bit on last byte */
367 return pb_write(stream, buffer, i);
370 bool checkreturn pb_encode_svarint(pb_ostream_t *stream, int64_t value)
374 zigzagged = (uint64_t)(~(value << 1));
376 zigzagged = (uint64_t)(value << 1);
378 return pb_encode_varint(stream, zigzagged);
381 bool checkreturn pb_encode_fixed32(pb_ostream_t *stream, const void *value)
383 #ifdef __BIG_ENDIAN__
384 const uint8_t *bytes = value;
386 lebytes[0] = bytes[3];
387 lebytes[1] = bytes[2];
388 lebytes[2] = bytes[1];
389 lebytes[3] = bytes[0];
390 return pb_write(stream, lebytes, 4);
392 return pb_write(stream, (const uint8_t*)value, 4);
396 bool checkreturn pb_encode_fixed64(pb_ostream_t *stream, const void *value)
398 #ifdef __BIG_ENDIAN__
399 const uint8_t *bytes = value;
401 lebytes[0] = bytes[7];
402 lebytes[1] = bytes[6];
403 lebytes[2] = bytes[5];
404 lebytes[3] = bytes[4];
405 lebytes[4] = bytes[3];
406 lebytes[5] = bytes[2];
407 lebytes[6] = bytes[1];
408 lebytes[7] = bytes[0];
409 return pb_write(stream, lebytes, 8);
411 return pb_write(stream, (const uint8_t*)value, 8);
415 bool checkreturn pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number)
417 uint64_t tag = wiretype | (field_number << 3);
418 return pb_encode_varint(stream, tag);
421 bool checkreturn pb_encode_tag_for_field(pb_ostream_t *stream, const pb_field_t *field)
423 pb_wire_type_t wiretype;
424 switch (PB_LTYPE(field->type))
426 case PB_LTYPE_VARINT:
427 case PB_LTYPE_SVARINT:
428 wiretype = PB_WT_VARINT;
431 case PB_LTYPE_FIXED32:
432 wiretype = PB_WT_32BIT;
435 case PB_LTYPE_FIXED64:
436 wiretype = PB_WT_64BIT;
440 case PB_LTYPE_STRING:
441 case PB_LTYPE_SUBMESSAGE:
442 wiretype = PB_WT_STRING;
446 PB_RETURN_ERROR(stream, "invalid field type");
449 return pb_encode_tag(stream, wiretype, field->tag);
452 bool checkreturn pb_encode_string(pb_ostream_t *stream, const uint8_t *buffer, size_t size)
454 if (!pb_encode_varint(stream, (uint64_t)size))
457 return pb_write(stream, buffer, size);
460 bool checkreturn pb_encode_submessage(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
462 /* First calculate the message size using a non-writing substream. */
463 pb_ostream_t substream = PB_OSTREAM_SIZING;
467 if (!pb_encode(&substream, fields, src_struct))
470 size = substream.bytes_written;
472 if (!pb_encode_varint(stream, (uint64_t)size))
475 if (stream->callback == NULL)
476 return pb_write(stream, NULL, size); /* Just sizing */
478 if (stream->bytes_written + size > stream->max_size)
479 PB_RETURN_ERROR(stream, "stream full");
481 /* Use a substream to verify that a callback doesn't write more than
482 * what it did the first time. */
483 substream.callback = stream->callback;
484 substream.state = stream->state;
485 substream.max_size = size;
486 substream.bytes_written = 0;
488 substream.errmsg = NULL;
491 status = pb_encode(&substream, fields, src_struct);
493 stream->bytes_written += substream.bytes_written;
494 stream->state = substream.state;
496 stream->errmsg = substream.errmsg;
499 if (substream.bytes_written != size)
500 PB_RETURN_ERROR(stream, "submsg size changed");
507 bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
511 switch (field->data_size)
513 case 1: value = *(const uint8_t*)src; break;
514 case 2: value = *(const uint16_t*)src; break;
515 case 4: value = *(const uint32_t*)src; break;
516 case 8: value = *(const uint64_t*)src; break;
517 default: PB_RETURN_ERROR(stream, "invalid data_size");
520 return pb_encode_varint(stream, value);
523 bool checkreturn pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
527 switch (field->data_size)
529 case 4: value = *(const int32_t*)src; break;
530 case 8: value = *(const int64_t*)src; break;
531 default: PB_RETURN_ERROR(stream, "invalid data_size");
534 return pb_encode_svarint(stream, value);
537 bool checkreturn pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src)
540 return pb_encode_fixed64(stream, src);
543 bool checkreturn pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src)
546 return pb_encode_fixed32(stream, src);
549 bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src)
551 const pb_bytes_array_t *bytes = (const pb_bytes_array_t*)src;
553 if (bytes->size + offsetof(pb_bytes_array_t, bytes) > field->data_size)
554 PB_RETURN_ERROR(stream, "bytes size exceeded");
556 return pb_encode_string(stream, bytes->bytes, bytes->size);
559 bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src)
561 /* strnlen() is not always available, so just use a for-loop */
563 const char *p = (const char*)src;
564 while (size < field->data_size && *p != '\0')
570 return pb_encode_string(stream, (const uint8_t*)src, size);
573 bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src)
575 if (field->ptr == NULL)
576 PB_RETURN_ERROR(stream, "invalid field descriptor");
578 return pb_encode_submessage(stream, (const pb_field_t*)field->ptr, src);