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 (PB_ATYPE(field->type) != PB_ATYPE_POINTER && 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))
176 /* Special case for strings */
177 if (PB_ATYPE(field->type) == PB_ATYPE_POINTER &&
178 PB_LTYPE(field->type) == PB_LTYPE_STRING)
180 if (!func(stream, field, *(const void**)p))
185 if (!func(stream, field, p))
188 p = (const char*)p + field->data_size;
195 /* Encode a field with static allocation, i.e. one whose data is stored
196 * in the structure itself. */
197 static bool checkreturn encode_static_field(pb_ostream_t *stream,
198 const pb_field_t *field, const void *pData)
204 func = PB_ENCODERS[PB_LTYPE(field->type)];
206 if (field->size_offset)
207 pSize = (const char*)pData + field->size_offset;
208 else if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
209 pSize = *(const void**)pData ? &dummy : pData;
213 if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
214 pData = *(const void**)pData;
216 switch (PB_HTYPE(field->type))
218 case PB_HTYPE_REQUIRED:
221 if (!pb_encode_tag_for_field(stream, field))
223 if (!func(stream, field, pData))
227 case PB_HTYPE_OPTIONAL:
228 if (*(const bool*)pSize)
230 if (!pb_encode_tag_for_field(stream, field))
233 if (!func(stream, field, pData))
238 case PB_HTYPE_REPEATED:
239 if (!encode_array(stream, field, pData, *(const size_t*)pSize, func))
244 PB_RETURN_ERROR(stream, "invalid field type");
250 /* Encode a field with callback semantics. This means that a user function is
251 * called to provide and encode the actual data. */
252 static bool checkreturn encode_callback_field(pb_ostream_t *stream,
253 const pb_field_t *field, const void *pData)
255 const pb_callback_t *callback = (const pb_callback_t*)pData;
257 #ifdef PB_OLD_CALLBACK_STYLE
258 const void *arg = callback->arg;
260 void * const *arg = &(callback->arg);
263 if (callback->funcs.encode != NULL)
265 if (!callback->funcs.encode(stream, field, arg))
266 PB_RETURN_ERROR(stream, "callback error");
271 /* Encode a single field of any callback or static type. */
272 static bool checkreturn encode_field(pb_ostream_t *stream,
273 const pb_field_t *field, const void *pData)
275 switch (PB_ATYPE(field->type))
277 case PB_ATYPE_STATIC:
278 case PB_ATYPE_POINTER:
279 return encode_static_field(stream, field, pData);
281 case PB_ATYPE_CALLBACK:
282 return encode_callback_field(stream, field, pData);
285 PB_RETURN_ERROR(stream, "invalid field type");
289 /* Default handler for extension fields. Expects to have a pb_field_t
290 * pointer in the extension->type->arg field. */
291 static bool checkreturn default_extension_encoder(pb_ostream_t *stream,
292 const pb_extension_t *extension)
294 const pb_field_t *field = (const pb_field_t*)extension->type->arg;
295 return encode_field(stream, field, extension->dest);
298 /* Walk through all the registered extensions and give them a chance
299 * to encode themselves. */
300 static bool checkreturn encode_extension_field(pb_ostream_t *stream,
301 const pb_field_t *field, const void *pData)
303 const pb_extension_t *extension = *(const pb_extension_t* const *)pData;
309 if (extension->type->encode)
310 status = extension->type->encode(stream, extension);
312 status = default_extension_encoder(stream, extension);
317 extension = extension->next;
323 /*********************
324 * Encode all fields *
325 *********************/
327 bool checkreturn pb_encode(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
329 const pb_field_t *field = fields;
330 const void *pData = src_struct;
331 size_t prev_size = 0;
333 while (field->tag != 0)
335 pData = (const char*)pData + prev_size + field->data_offset;
336 if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
337 prev_size = sizeof(const void*);
339 prev_size = field->data_size;
341 /* Special case for static arrays */
342 if (PB_ATYPE(field->type) == PB_ATYPE_STATIC &&
343 PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
345 prev_size *= field->array_size;
348 if (PB_LTYPE(field->type) == PB_LTYPE_EXTENSION)
350 /* Special case for the extension field placeholder */
351 if (!encode_extension_field(stream, field, pData))
357 if (!encode_field(stream, field, pData))
367 bool pb_encode_delimited(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
369 return pb_encode_submessage(stream, fields, src_struct);
372 /********************
374 ********************/
375 bool checkreturn pb_encode_varint(pb_ostream_t *stream, uint64_t value)
381 return pb_write(stream, (uint8_t*)&value, 1);
385 buffer[i] = (uint8_t)((value & 0x7F) | 0x80);
389 buffer[i-1] &= 0x7F; /* Unset top bit on last byte */
391 return pb_write(stream, buffer, i);
394 bool checkreturn pb_encode_svarint(pb_ostream_t *stream, int64_t value)
398 zigzagged = (uint64_t)(~(value << 1));
400 zigzagged = (uint64_t)(value << 1);
402 return pb_encode_varint(stream, zigzagged);
405 bool checkreturn pb_encode_fixed32(pb_ostream_t *stream, const void *value)
407 #ifdef __BIG_ENDIAN__
408 const uint8_t *bytes = value;
410 lebytes[0] = bytes[3];
411 lebytes[1] = bytes[2];
412 lebytes[2] = bytes[1];
413 lebytes[3] = bytes[0];
414 return pb_write(stream, lebytes, 4);
416 return pb_write(stream, (const uint8_t*)value, 4);
420 bool checkreturn pb_encode_fixed64(pb_ostream_t *stream, const void *value)
422 #ifdef __BIG_ENDIAN__
423 const uint8_t *bytes = value;
425 lebytes[0] = bytes[7];
426 lebytes[1] = bytes[6];
427 lebytes[2] = bytes[5];
428 lebytes[3] = bytes[4];
429 lebytes[4] = bytes[3];
430 lebytes[5] = bytes[2];
431 lebytes[6] = bytes[1];
432 lebytes[7] = bytes[0];
433 return pb_write(stream, lebytes, 8);
435 return pb_write(stream, (const uint8_t*)value, 8);
439 bool checkreturn pb_encode_tag(pb_ostream_t *stream, pb_wire_type_t wiretype, uint32_t field_number)
441 uint64_t tag = wiretype | (field_number << 3);
442 return pb_encode_varint(stream, tag);
445 bool checkreturn pb_encode_tag_for_field(pb_ostream_t *stream, const pb_field_t *field)
447 pb_wire_type_t wiretype;
448 switch (PB_LTYPE(field->type))
450 case PB_LTYPE_VARINT:
451 case PB_LTYPE_UVARINT:
452 case PB_LTYPE_SVARINT:
453 wiretype = PB_WT_VARINT;
456 case PB_LTYPE_FIXED32:
457 wiretype = PB_WT_32BIT;
460 case PB_LTYPE_FIXED64:
461 wiretype = PB_WT_64BIT;
465 case PB_LTYPE_STRING:
466 case PB_LTYPE_SUBMESSAGE:
467 wiretype = PB_WT_STRING;
471 PB_RETURN_ERROR(stream, "invalid field type");
474 return pb_encode_tag(stream, wiretype, field->tag);
477 bool checkreturn pb_encode_string(pb_ostream_t *stream, const uint8_t *buffer, size_t size)
479 if (!pb_encode_varint(stream, (uint64_t)size))
482 return pb_write(stream, buffer, size);
485 bool checkreturn pb_encode_submessage(pb_ostream_t *stream, const pb_field_t fields[], const void *src_struct)
487 /* First calculate the message size using a non-writing substream. */
488 pb_ostream_t substream = PB_OSTREAM_SIZING;
492 if (!pb_encode(&substream, fields, src_struct))
495 size = substream.bytes_written;
497 if (!pb_encode_varint(stream, (uint64_t)size))
500 if (stream->callback == NULL)
501 return pb_write(stream, NULL, size); /* Just sizing */
503 if (stream->bytes_written + size > stream->max_size)
504 PB_RETURN_ERROR(stream, "stream full");
506 /* Use a substream to verify that a callback doesn't write more than
507 * what it did the first time. */
508 substream.callback = stream->callback;
509 substream.state = stream->state;
510 substream.max_size = size;
511 substream.bytes_written = 0;
513 substream.errmsg = NULL;
516 status = pb_encode(&substream, fields, src_struct);
518 stream->bytes_written += substream.bytes_written;
519 stream->state = substream.state;
521 stream->errmsg = substream.errmsg;
524 if (substream.bytes_written != size)
525 PB_RETURN_ERROR(stream, "submsg size changed");
532 bool checkreturn pb_enc_varint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
536 /* Cases 1 and 2 are for compilers that have smaller types for bool
538 switch (field->data_size)
540 case 1: value = *(const int8_t*)src; break;
541 case 2: value = *(const int16_t*)src; break;
542 case 4: value = *(const int32_t*)src; break;
543 case 8: value = *(const int64_t*)src; break;
544 default: PB_RETURN_ERROR(stream, "invalid data_size");
547 return pb_encode_varint(stream, (uint64_t)value);
550 bool checkreturn pb_enc_uvarint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
554 switch (field->data_size)
556 case 4: value = *(const uint32_t*)src; break;
557 case 8: value = *(const uint64_t*)src; break;
558 default: PB_RETURN_ERROR(stream, "invalid data_size");
561 return pb_encode_varint(stream, value);
564 bool checkreturn pb_enc_svarint(pb_ostream_t *stream, const pb_field_t *field, const void *src)
568 switch (field->data_size)
570 case 4: value = *(const int32_t*)src; break;
571 case 8: value = *(const int64_t*)src; break;
572 default: PB_RETURN_ERROR(stream, "invalid data_size");
575 return pb_encode_svarint(stream, value);
578 bool checkreturn pb_enc_fixed64(pb_ostream_t *stream, const pb_field_t *field, const void *src)
581 return pb_encode_fixed64(stream, src);
584 bool checkreturn pb_enc_fixed32(pb_ostream_t *stream, const pb_field_t *field, const void *src)
587 return pb_encode_fixed32(stream, src);
590 bool checkreturn pb_enc_bytes(pb_ostream_t *stream, const pb_field_t *field, const void *src)
592 const pb_bytes_array_t *bytes = (const pb_bytes_array_t*)src;
594 if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
596 return pb_encode_string(stream, *(const uint8_t**)bytes->bytes, bytes->size);
600 if (bytes->size + offsetof(pb_bytes_array_t, bytes) > field->data_size)
601 PB_RETURN_ERROR(stream, "bytes size exceeded");
603 return pb_encode_string(stream, bytes->bytes, bytes->size);
607 bool checkreturn pb_enc_string(pb_ostream_t *stream, const pb_field_t *field, const void *src)
609 /* strnlen() is not always available, so just use a for-loop */
611 const char *p = (const char*)src;
612 if (PB_ATYPE(field->type) == PB_ATYPE_POINTER)
622 while (size < field->data_size && *p != '\0')
628 return pb_encode_string(stream, (const uint8_t*)src, size);
631 bool checkreturn pb_enc_submessage(pb_ostream_t *stream, const pb_field_t *field, const void *src)
633 if (field->ptr == NULL)
634 PB_RETURN_ERROR(stream, "invalid field descriptor");
636 return pb_encode_submessage(stream, (const pb_field_t*)field->ptr, src);