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_uvarint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
32 static bool checkreturn pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src);
33 static bool checkreturn pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src);
34 static bool checkreturn pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src);
35 static bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src);
36 static bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src);
37 static bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src);
39 /* --- Function pointers to field encoders ---
40 * Order in the array must match pb_action_t LTYPE numbering.
42 static const pb_encoder_t PB_ENCODERS[PB_LTYPES_COUNT] = {
55 /*******************************
56 * pb_ostream_t implementation *
57 *******************************/
59 static bool checkreturn buf_write(pb_ostream_t *stream, const uint8_t *buf, size_t count)
61 uint8_t *dest = (uint8_t*)stream->state;
62 stream->state = dest + count;
70 pb_ostream_t pb_ostream_from_buffer(uint8_t *buf, size_t bufsize)
74 stream.callback = (void*)1; /* Just a marker value */
76 stream.callback = &buf_write;
79 stream.max_size = bufsize;
80 stream.bytes_written = 0;
87 bool checkreturn pb_write(pb_ostream_t *stream, const uint8_t *buf, size_t count)
89 if (stream->callback != NULL)
91 if (stream->bytes_written + count > stream->max_size)
92 PB_RETURN_ERROR(stream, "stream full");
95 if (!buf_write(stream, buf, count))
96 PB_RETURN_ERROR(stream, "io error");
98 if (!stream->callback(stream, buf, count))
99 PB_RETURN_ERROR(stream, "io error");
103 stream->bytes_written += count;
107 /*************************
108 * Encode a single field *
109 *************************/
111 /* Encode a static array. Handles the size calculations and possible packing. */
112 static bool checkreturn encode_array(pb_ostream_t *stream, const pb_field_t *field,
113 const void *pData, size_t count, pb_encoder_t func)
122 if (count > field->array_size)
123 PB_RETURN_ERROR(stream, "array max size exceeded");
125 /* We always pack arrays if the datatype allows it. */
126 if (PB_LTYPE(field->type) <= PB_LTYPE_LAST_PACKABLE)
128 if (!pb_encode_tag(stream, PB_WT_STRING, field->tag))
131 /* Determine the total size of packed array. */
132 if (PB_LTYPE(field->type) == PB_LTYPE_FIXED32)
136 else if (PB_LTYPE(field->type) == PB_LTYPE_FIXED64)
142 pb_ostream_t sizestream = PB_OSTREAM_SIZING;
144 for (i = 0; i < count; i++)
146 if (!func(&sizestream, field, p))
148 p = (const char*)p + field->data_size;
150 size = sizestream.bytes_written;
153 if (!pb_encode_varint(stream, (uint64_t)size))
156 if (stream->callback == NULL)
157 return pb_write(stream, NULL, size); /* Just sizing.. */
161 for (i = 0; i < count; i++)
163 if (!func(stream, field, p))
165 p = (const char*)p + field->data_size;
171 for (i = 0; i < count; i++)
173 if (!pb_encode_tag_for_field(stream, field))
175 if (!func(stream, field, p))
177 p = (const char*)p + field->data_size;
184 /* Encode a field with static allocation, i.e. one whose data is stored
185 * in the structure itself. */
186 static bool checkreturn encode_static_field(pb_ostream_t *stream,
187 const pb_field_t *field, const void *pData)
193 func = PB_ENCODERS[PB_LTYPE(field->type)];
195 if (field->size_offset)
196 pSize = (const char*)pData + field->size_offset;
200 switch (PB_HTYPE(field->type))
202 case PB_HTYPE_REQUIRED:
203 if (!pb_encode_tag_for_field(stream, field))
205 if (!func(stream, field, pData))
209 case PB_HTYPE_OPTIONAL:
210 if (*(const bool*)pSize)
212 if (!pb_encode_tag_for_field(stream, field))
215 if (!func(stream, field, pData))
220 case PB_HTYPE_REPEATED:
221 if (!encode_array(stream, field, pData, *(const size_t*)pSize, func))
226 PB_RETURN_ERROR(stream, "invalid field type");
232 /* Encode a field with callback semantics. This means that a user function is
233 * called to provide and encode the actual data. */
234 static bool checkreturn encode_callback_field(pb_ostream_t *stream,
235 const pb_field_t *field, const void *pData)
237 const pb_callback_t *callback = (const pb_callback_t*)pData;
239 #ifdef PB_OLD_CALLBACK_STYLE
240 const void *arg = callback->arg;
242 void * const *arg = &(callback->arg);
245 if (callback->funcs.encode != NULL)
247 if (!callback->funcs.encode(stream, field, arg))
248 PB_RETURN_ERROR(stream, "callback error");
253 /* Encode a single field of any callback or static type. */
254 static bool checkreturn encode_field(pb_ostream_t *stream,
255 const pb_field_t *field, const void *pData)
257 switch (PB_ATYPE(field->type))
259 case PB_ATYPE_STATIC:
260 return encode_static_field(stream, field, pData);
262 case PB_ATYPE_CALLBACK:
263 return encode_callback_field(stream, field, pData);
266 PB_RETURN_ERROR(stream, "invalid field type");
270 /* Default handler for extension fields. Expects to have a pb_field_t
271 * pointer in the extension->type->arg field. */
272 static bool checkreturn default_extension_encoder(pb_ostream_t *stream,
273 const pb_extension_t *extension)
275 const pb_field_t *field = (const pb_field_t*)extension->type->arg;
276 return encode_field(stream, field, extension->dest);
279 /* Walk through all the registered extensions and give them a chance
280 * to encode themselves. */
281 static bool checkreturn encode_extension_field(pb_ostream_t *stream,
282 const pb_field_t *field, const void *pData)
284 const pb_extension_t *extension = *(const pb_extension_t* const *)pData;
290 if (extension->type->encode)
291 status = extension->type->encode(stream, extension);
293 status = default_extension_encoder(stream, extension);
298 extension = extension->next;
304 /*********************
305 * Encode all fields *
306 *********************/
308 bool checkreturn pb_encode(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
310 const pb_field_t *field = fields;
311 const void *pData = src_struct;
312 size_t prev_size = 0;
314 while (field->tag != 0)
316 pData = (const char*)pData + prev_size + field->data_offset;
317 prev_size = field->data_size;
319 /* Special case for static arrays */
320 if (PB_ATYPE(field->type) == PB_ATYPE_STATIC &&
321 PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
323 prev_size *= field->array_size;
326 if (PB_LTYPE(field->type) == PB_LTYPE_EXTENSION)
328 /* Special case for the extension field placeholder */
329 if (!encode_extension_field(stream, field, pData))
335 if (!encode_field(stream, field, pData))
345 bool pb_encode_delimited(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
347 return pb_encode_submessage(stream, fields, src_struct);
350 /********************
352 ********************/
353 bool checkreturn pb_encode_varint(pb_ostream_t *stream, uint64_t value)
359 return pb_write(stream, (uint8_t*)&value, 1);
363 buffer[i] = (uint8_t)((value & 0x7F) | 0x80);
367 buffer[i-1] &= 0x7F; /* Unset top bit on last byte */
369 return pb_write(stream, buffer, i);
372 bool checkreturn pb_encode_svarint(pb_ostream_t *stream, int64_t value)
376 zigzagged = (uint64_t)(~(value << 1));
378 zigzagged = (uint64_t)(value << 1);
380 return pb_encode_varint(stream, zigzagged);
383 bool checkreturn pb_encode_fixed32(pb_ostream_t *stream, const void *value)
385 #ifdef __BIG_ENDIAN__
386 const uint8_t *bytes = value;
388 lebytes[0] = bytes[3];
389 lebytes[1] = bytes[2];
390 lebytes[2] = bytes[1];
391 lebytes[3] = bytes[0];
392 return pb_write(stream, lebytes, 4);
394 return pb_write(stream, (const uint8_t*)value, 4);
398 bool checkreturn pb_encode_fixed64(pb_ostream_t *stream, const void *value)
400 #ifdef __BIG_ENDIAN__
401 const uint8_t *bytes = value;
403 lebytes[0] = bytes[7];
404 lebytes[1] = bytes[6];
405 lebytes[2] = bytes[5];
406 lebytes[3] = bytes[4];
407 lebytes[4] = bytes[3];
408 lebytes[5] = bytes[2];
409 lebytes[6] = bytes[1];
410 lebytes[7] = bytes[0];
411 return pb_write(stream, lebytes, 8);
413 return pb_write(stream, (const uint8_t*)value, 8);
417 bool checkreturn pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number)
419 uint64_t tag = wiretype | (field_number << 3);
420 return pb_encode_varint(stream, tag);
423 bool checkreturn pb_encode_tag_for_field(pb_ostream_t *stream, const pb_field_t *field)
425 pb_wire_type_t wiretype;
426 switch (PB_LTYPE(field->type))
428 case PB_LTYPE_VARINT:
429 case PB_LTYPE_UVARINT:
430 case PB_LTYPE_SVARINT:
431 wiretype = PB_WT_VARINT;
434 case PB_LTYPE_FIXED32:
435 wiretype = PB_WT_32BIT;
438 case PB_LTYPE_FIXED64:
439 wiretype = PB_WT_64BIT;
443 case PB_LTYPE_STRING:
444 case PB_LTYPE_SUBMESSAGE:
445 wiretype = PB_WT_STRING;
449 PB_RETURN_ERROR(stream, "invalid field type");
452 return pb_encode_tag(stream, wiretype, field->tag);
455 bool checkreturn pb_encode_string(pb_ostream_t *stream, const uint8_t *buffer, size_t size)
457 if (!pb_encode_varint(stream, (uint64_t)size))
460 return pb_write(stream, buffer, size);
463 bool checkreturn pb_encode_submessage(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
465 /* First calculate the message size using a non-writing substream. */
466 pb_ostream_t substream = PB_OSTREAM_SIZING;
470 if (!pb_encode(&substream, fields, src_struct))
473 size = substream.bytes_written;
475 if (!pb_encode_varint(stream, (uint64_t)size))
478 if (stream->callback == NULL)
479 return pb_write(stream, NULL, size); /* Just sizing */
481 if (stream->bytes_written + size > stream->max_size)
482 PB_RETURN_ERROR(stream, "stream full");
484 /* Use a substream to verify that a callback doesn't write more than
485 * what it did the first time. */
486 substream.callback = stream->callback;
487 substream.state = stream->state;
488 substream.max_size = size;
489 substream.bytes_written = 0;
491 substream.errmsg = NULL;
494 status = pb_encode(&substream, fields, src_struct);
496 stream->bytes_written += substream.bytes_written;
497 stream->state = substream.state;
499 stream->errmsg = substream.errmsg;
502 if (substream.bytes_written != size)
503 PB_RETURN_ERROR(stream, "submsg size changed");
510 bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
514 /* Cases 1 and 2 are for compilers that have smaller types for bool
516 switch (field->data_size)
518 case 1: value = *(const int8_t*)src; break;
519 case 2: value = *(const int16_t*)src; break;
520 case 4: value = *(const int32_t*)src; break;
521 case 8: value = *(const int64_t*)src; break;
522 default: PB_RETURN_ERROR(stream, "invalid data_size");
525 return pb_encode_varint(stream, (uint64_t)value);
528 bool checkreturn pb_enc_uvarint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
532 switch (field->data_size)
534 case 4: value = *(const uint32_t*)src; break;
535 case 8: value = *(const uint64_t*)src; break;
536 default: PB_RETURN_ERROR(stream, "invalid data_size");
539 return pb_encode_varint(stream, value);
542 bool checkreturn pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
546 switch (field->data_size)
548 case 4: value = *(const int32_t*)src; break;
549 case 8: value = *(const int64_t*)src; break;
550 default: PB_RETURN_ERROR(stream, "invalid data_size");
553 return pb_encode_svarint(stream, value);
556 bool checkreturn pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src)
559 return pb_encode_fixed64(stream, src);
562 bool checkreturn pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src)
565 return pb_encode_fixed32(stream, src);
568 bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src)
570 const pb_bytes_array_t *bytes = (const pb_bytes_array_t*)src;
572 if (bytes->size + offsetof(pb_bytes_array_t, bytes) > field->data_size)
573 PB_RETURN_ERROR(stream, "bytes size exceeded");
575 return pb_encode_string(stream, bytes->bytes, bytes->size);
578 bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src)
580 /* strnlen() is not always available, so just use a for-loop */
582 const char *p = (const char*)src;
583 while (size < field->data_size && *p != '\0')
589 return pb_encode_string(stream, (const uint8_t*)src, size);
592 bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src)
594 if (field->ptr == NULL)
595 PB_RETURN_ERROR(stream, "invalid field descriptor");
597 return pb_encode_submessage(stream, (const pb_field_t*)field->ptr, src);