pb_decode.c

00001 /* pb_decode.c -- decode a protobuf using minimal resources
00002  *
00003  * 2011 Petteri Aimonen <jpa@kapsi.fi>
00004  */
00005 
00006 /* Use the GCC warn_unused_result attribute to check that all return values
00007  * are propagated correctly. On other compilers and gcc before 3.4.0 just
00008  * ignore the annotation.
00009  */
00010 #if !defined(__GNUC__) || ( __GNUC__ < 3) || (__GNUC__ == 3 && __GNUC_MINOR__ < 4)
00011     #define checkreturn
00012 #else
00013     #define checkreturn __attribute__((warn_unused_result))
00014 #endif
00015 
00016 #define NANOPB_INTERNALS
00017 #include "pb.h"
00018 #include "pb_decode.h"
00019 
00020 /**************************************
00021  * Declarations internal to this file *
00022  **************************************/
00023 
00024 /* Iterator for pb_field_t list */
00025 typedef struct {
00026     const pb_field_t *start; /* Start of the pb_field_t array */
00027     const pb_field_t *pos; /* Current position of the iterator */
00028     unsigned field_index; /* Zero-based index of the field. */
00029     unsigned required_field_index; /* Zero-based index that counts only the required fields */
00030     void *dest_struct; /* Pointer to the destination structure to decode to */
00031     void *pData; /* Pointer where to store current field value */
00032     void *pSize; /* Pointer where to store the size of current array field */
00033 } pb_field_iterator_t;
00034 
00035 typedef bool (*pb_decoder_t)(pb_istream_t *stream, const pb_field_t *field, void *dest) checkreturn;
00036 
00037 static bool checkreturn buf_read(pb_istream_t *stream, uint8_t *buf, size_t count);
00038 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest);
00039 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size);
00040 static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct);
00041 static bool pb_field_next(pb_field_iterator_t *iter);
00042 static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag);
00043 static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
00044 static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
00045 static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
00046 static bool checkreturn default_extension_decoder(pb_istream_t *stream, pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type);
00047 static bool checkreturn decode_extension(pb_istream_t *stream, uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter);
00048 static bool checkreturn find_extension_field(pb_field_iterator_t *iter);
00049 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct);
00050 static bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest);
00051 static bool checkreturn pb_dec_uvarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
00052 static bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest);
00053 static bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest);
00054 static bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest);
00055 static bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest);
00056 static bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest);
00057 static bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest);
00058 static bool checkreturn pb_skip_varint(pb_istream_t *stream);
00059 static bool checkreturn pb_skip_string(pb_istream_t *stream);
00060 
00061 /* --- Function pointers to field decoders ---
00062  * Order in the array must match pb_action_t LTYPE numbering.
00063  */
00064 static const pb_decoder_t PB_DECODERS[PB_LTYPES_COUNT] = {
00065     &pb_dec_varint,
00066     &pb_dec_uvarint,
00067     &pb_dec_svarint,
00068     &pb_dec_fixed32,
00069     &pb_dec_fixed64,
00070     
00071     &pb_dec_bytes,
00072     &pb_dec_string,
00073     &pb_dec_submessage,
00074     NULL /* extensions */
00075 };
00076 
00077 /*******************************
00078  * pb_istream_t implementation *
00079  *******************************/
00080 
00081 static bool checkreturn buf_read(pb_istream_t *stream, uint8_t *buf, size_t count)
00082 {
00083     uint8_t *source = (uint8_t*)stream->state;
00084     stream->state = source + count;
00085     
00086     if (buf != NULL)
00087     {
00088         while (count--)
00089             *buf++ = *source++;
00090     }
00091     
00092     return true;
00093 }
00094 
00095 bool checkreturn pb_read(pb_istream_t *stream, uint8_t *buf, size_t count)
00096 {
00097 #ifndef PB_BUFFER_ONLY
00098     if (buf == NULL && stream->callback != buf_read)
00099     {
00100         /* Skip input bytes */
00101         uint8_t tmp[16];
00102         while (count > 16)
00103         {
00104             if (!pb_read(stream, tmp, 16))
00105                 return false;
00106             
00107             count -= 16;
00108         }
00109         
00110         return pb_read(stream, tmp, count);
00111     }
00112 #endif
00113 
00114     if (stream->bytes_left < count)
00115         PB_RETURN_ERROR(stream, "end-of-stream");
00116     
00117 #ifndef PB_BUFFER_ONLY
00118     if (!stream->callback(stream, buf, count))
00119         PB_RETURN_ERROR(stream, "io error");
00120 #else
00121     if (!buf_read(stream, buf, count))
00122         return false;
00123 #endif
00124     
00125     stream->bytes_left -= count;
00126     return true;
00127 }
00128 
00129 /* Read a single byte from input stream. buf may not be NULL.
00130  * This is an optimization for the varint decoding. */
00131 static bool checkreturn pb_readbyte(pb_istream_t *stream, uint8_t *buf)
00132 {
00133     if (!stream->bytes_left)
00134         PB_RETURN_ERROR(stream, "end-of-stream");
00135 
00136 #ifndef PB_BUFFER_ONLY
00137     if (!stream->callback(stream, buf, 1))
00138         PB_RETURN_ERROR(stream, "io error");
00139 #else
00140     *buf = *(uint8_t*)stream->state;
00141     stream->state = (uint8_t*)stream->state + 1;
00142 #endif
00143 
00144     stream->bytes_left--;
00145     
00146     return true;    
00147 }
00148 
00149 pb_istream_t pb_istream_from_buffer(uint8_t *buf, size_t bufsize)
00150 {
00151     pb_istream_t stream;
00152 #ifdef PB_BUFFER_ONLY
00153     stream.callback = NULL;
00154 #else
00155     stream.callback = &buf_read;
00156 #endif
00157     stream.state = buf;
00158     stream.bytes_left = bufsize;
00159 #ifndef PB_NO_ERRMSG
00160     stream.errmsg = NULL;
00161 #endif
00162     return stream;
00163 }
00164 
00165 /********************
00166  * Helper functions *
00167  ********************/
00168 
00169 static bool checkreturn pb_decode_varint32(pb_istream_t *stream, uint32_t *dest)
00170 {
00171     uint8_t byte;
00172     uint32_t result;
00173     
00174     if (!pb_readbyte(stream, &byte))
00175         return false;
00176     
00177     if (!(byte & 0x80))
00178     {
00179         /* Quick case, 1 byte value */
00180         result = byte;
00181     }
00182     else
00183     {
00184         /* Multibyte case */
00185         uint8_t bitpos = 7;
00186         result = byte & 0x7F;
00187         
00188         do
00189         {
00190             if (bitpos >= 32)
00191                 PB_RETURN_ERROR(stream, "varint overflow");
00192             
00193             if (!pb_readbyte(stream, &byte))
00194                 return false;
00195             
00196             result |= (uint32_t)(byte & 0x7F) << bitpos;
00197             bitpos = (uint8_t)(bitpos + 7);
00198         } while (byte & 0x80);
00199    }
00200    
00201    *dest = result;
00202    return true;
00203 }
00204 
00205 bool checkreturn pb_decode_varint(pb_istream_t *stream, uint64_t *dest)
00206 {
00207     uint8_t byte;
00208     uint8_t bitpos = 0;
00209     uint64_t result = 0;
00210     
00211     do
00212     {
00213         if (bitpos >= 64)
00214             PB_RETURN_ERROR(stream, "varint overflow");
00215         
00216         if (!pb_readbyte(stream, &byte))
00217             return false;
00218 
00219         result |= (uint64_t)(byte & 0x7F) << bitpos;
00220         bitpos = (uint8_t)(bitpos + 7);
00221     } while (byte & 0x80);
00222     
00223     *dest = result;
00224     return true;
00225 }
00226 
00227 bool checkreturn pb_skip_varint(pb_istream_t *stream)
00228 {
00229     uint8_t byte;
00230     do
00231     {
00232         if (!pb_read(stream, &byte, 1))
00233             return false;
00234     } while (byte & 0x80);
00235     return true;
00236 }
00237 
00238 bool checkreturn pb_skip_string(pb_istream_t *stream)
00239 {
00240     uint32_t length;
00241     if (!pb_decode_varint32(stream, &length))
00242         return false;
00243     
00244     return pb_read(stream, NULL, length);
00245 }
00246 
00247 bool checkreturn pb_decode_tag(pb_istream_t *stream, pb_wire_type_t *wire_type, uint32_t *tag, bool *eof)
00248 {
00249     uint32_t temp;
00250     *eof = false;
00251     *wire_type = (pb_wire_type_t) 0;
00252     *tag = 0;
00253     
00254     if (!pb_decode_varint32(stream, &temp))
00255     {
00256         if (stream->bytes_left == 0)
00257             *eof = true;
00258 
00259         return false;
00260     }
00261     
00262     if (temp == 0)
00263     {
00264         *eof = true; /* Special feature: allow 0-terminated messages. */
00265         return false;
00266     }
00267     
00268     *tag = temp >> 3;
00269     *wire_type = (pb_wire_type_t)(temp & 7);
00270     return true;
00271 }
00272 
00273 bool checkreturn pb_skip_field(pb_istream_t *stream, pb_wire_type_t wire_type)
00274 {
00275     switch (wire_type)
00276     {
00277         case PB_WT_VARINT: return pb_skip_varint(stream);
00278         case PB_WT_64BIT: return pb_read(stream, NULL, 8);
00279         case PB_WT_STRING: return pb_skip_string(stream);
00280         case PB_WT_32BIT: return pb_read(stream, NULL, 4);
00281         default: PB_RETURN_ERROR(stream, "invalid wire_type");
00282     }
00283 }
00284 
00285 /* Read a raw value to buffer, for the purpose of passing it to callback as
00286  * a substream. Size is maximum size on call, and actual size on return.
00287  */
00288 static bool checkreturn read_raw_value(pb_istream_t *stream, pb_wire_type_t wire_type, uint8_t *buf, size_t *size)
00289 {
00290     size_t max_size = *size;
00291     switch (wire_type)
00292     {
00293         case PB_WT_VARINT:
00294             *size = 0;
00295             do
00296             {
00297                 (*size)++;
00298                 if (*size > max_size) return false;
00299                 if (!pb_read(stream, buf, 1)) return false;
00300             } while (*buf++ & 0x80);
00301             return true;
00302             
00303         case PB_WT_64BIT:
00304             *size = 8;
00305             return pb_read(stream, buf, 8);
00306         
00307         case PB_WT_32BIT:
00308             *size = 4;
00309             return pb_read(stream, buf, 4);
00310         
00311         default: PB_RETURN_ERROR(stream, "invalid wire_type");
00312     }
00313 }
00314 
00315 /* Decode string length from stream and return a substream with limited length.
00316  * Remember to close the substream using pb_close_string_substream().
00317  */
00318 bool checkreturn pb_make_string_substream(pb_istream_t *stream, pb_istream_t *substream)
00319 {
00320     uint32_t size;
00321     if (!pb_decode_varint32(stream, &size))
00322         return false;
00323     
00324     *substream = *stream;
00325     if (substream->bytes_left < size)
00326         PB_RETURN_ERROR(stream, "parent stream too short");
00327     
00328     substream->bytes_left = size;
00329     stream->bytes_left -= size;
00330     return true;
00331 }
00332 
00333 void pb_close_string_substream(pb_istream_t *stream, pb_istream_t *substream)
00334 {
00335     stream->state = substream->state;
00336 
00337 #ifndef PB_NO_ERRMSG
00338     stream->errmsg = substream->errmsg;
00339 #endif
00340 }
00341 
00342 static void pb_field_init(pb_field_iterator_t *iter, const pb_field_t *fields, void *dest_struct)
00343 {
00344     iter->start = iter->pos = fields;
00345     iter->field_index = 0;
00346     iter->required_field_index = 0;
00347     iter->pData = (char*)dest_struct + iter->pos->data_offset;
00348     iter->pSize = (char*)iter->pData + iter->pos->size_offset;
00349     iter->dest_struct = dest_struct;
00350 }
00351 
00352 static bool pb_field_next(pb_field_iterator_t *iter)
00353 {
00354     bool notwrapped = true;
00355     size_t prev_size = iter->pos->data_size;
00356     
00357     if (PB_ATYPE(iter->pos->type) == PB_ATYPE_STATIC &&
00358         PB_HTYPE(iter->pos->type) == PB_HTYPE_REPEATED)
00359     {
00360         prev_size *= iter->pos->array_size;
00361     }
00362     
00363     if (iter->pos->tag == 0)
00364         return false; /* Only happens with empty message types */
00365     
00366     if (PB_HTYPE(iter->pos->type) == PB_HTYPE_REQUIRED)
00367         iter->required_field_index++;
00368     
00369     iter->pos++;
00370     iter->field_index++;
00371     if (iter->pos->tag == 0)
00372     {
00373         iter->pos = iter->start;
00374         iter->field_index = 0;
00375         iter->required_field_index = 0;
00376         iter->pData = iter->dest_struct;
00377         prev_size = 0;
00378         notwrapped = false;
00379     }
00380     
00381     iter->pData = (char*)iter->pData + prev_size + iter->pos->data_offset;
00382     iter->pSize = (char*)iter->pData + iter->pos->size_offset;
00383     return notwrapped;
00384 }
00385 
00386 static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag)
00387 {
00388     unsigned start = iter->field_index;
00389     
00390     do {
00391         if (iter->pos->tag == tag &&
00392             PB_LTYPE(iter->pos->type) != PB_LTYPE_EXTENSION)
00393         {
00394             return true;
00395         }
00396         pb_field_next(iter);
00397     } while (iter->field_index != start);
00398     
00399     return false;
00400 }
00401 
00402 /*************************
00403  * Decode a single field *
00404  *************************/
00405 
00406 static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
00407 {
00408     pb_type_t type;
00409     pb_decoder_t func;
00410     
00411     type = iter->pos->type;
00412     func = PB_DECODERS[PB_LTYPE(type)];
00413 
00414     switch (PB_HTYPE(type))
00415     {
00416         case PB_HTYPE_REQUIRED:
00417             return func(stream, iter->pos, iter->pData);
00418             
00419         case PB_HTYPE_OPTIONAL:
00420             *(bool*)iter->pSize = true;
00421             return func(stream, iter->pos, iter->pData);
00422     
00423         case PB_HTYPE_REPEATED:
00424             if (wire_type == PB_WT_STRING
00425                 && PB_LTYPE(type) <= PB_LTYPE_LAST_PACKABLE)
00426             {
00427                 /* Packed array */
00428                 bool status = true;
00429                 size_t *size = (size_t*)iter->pSize;
00430                 pb_istream_t substream;
00431                 if (!pb_make_string_substream(stream, &substream))
00432                     return false;
00433                 
00434                 while (substream.bytes_left && *size < iter->pos->array_size)
00435                 {
00436                     void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
00437                     if (!func(&substream, iter->pos, pItem))
00438                     {
00439                         status = false;
00440                         break;
00441                     }
00442                     (*size)++;
00443                 }
00444                 pb_close_string_substream(stream, &substream);
00445                 
00446                 if (substream.bytes_left != 0)
00447                     PB_RETURN_ERROR(stream, "array overflow");
00448                 
00449                 return status;
00450             }
00451             else
00452             {
00453                 /* Repeated field */
00454                 size_t *size = (size_t*)iter->pSize;
00455                 void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
00456                 if (*size >= iter->pos->array_size)
00457                     PB_RETURN_ERROR(stream, "array overflow");
00458                 
00459                 (*size)++;
00460                 return func(stream, iter->pos, pItem);
00461             }
00462 
00463         default:
00464             PB_RETURN_ERROR(stream, "invalid field type");
00465     }
00466 }
00467 
00468 static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
00469 {
00470     pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
00471     
00472 #ifdef PB_OLD_CALLBACK_STYLE
00473     void *arg = pCallback->arg;
00474 #else
00475     void **arg = &(pCallback->arg);
00476 #endif
00477     
00478     if (pCallback->funcs.decode == NULL)
00479         return pb_skip_field(stream, wire_type);
00480     
00481     if (wire_type == PB_WT_STRING)
00482     {
00483         pb_istream_t substream;
00484         
00485         if (!pb_make_string_substream(stream, &substream))
00486             return false;
00487         
00488         do
00489         {
00490             if (!pCallback->funcs.decode(&substream, iter->pos, arg))
00491                 PB_RETURN_ERROR(stream, "callback failed");
00492         } while (substream.bytes_left);
00493         
00494         pb_close_string_substream(stream, &substream);
00495         return true;
00496     }
00497     else
00498     {
00499         /* Copy the single scalar value to stack.
00500          * This is required so that we can limit the stream length,
00501          * which in turn allows to use same callback for packed and
00502          * not-packed fields. */
00503         pb_istream_t substream;
00504         uint8_t buffer[10];
00505         size_t size = sizeof(buffer);
00506         
00507         if (!read_raw_value(stream, wire_type, buffer, &size))
00508             return false;
00509         substream = pb_istream_from_buffer(buffer, size);
00510         
00511         return pCallback->funcs.decode(&substream, iter->pos, arg);
00512     }
00513 }
00514 
00515 static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
00516 {
00517     switch (PB_ATYPE(iter->pos->type))
00518     {
00519         case PB_ATYPE_STATIC:
00520             return decode_static_field(stream, wire_type, iter);
00521         
00522         case PB_ATYPE_CALLBACK:
00523             return decode_callback_field(stream, wire_type, iter);
00524         
00525         default:
00526             PB_RETURN_ERROR(stream, "invalid field type");
00527     }
00528 }
00529 
00530 /* Default handler for extension fields. Expects a pb_field_t structure
00531  * in extension->type->arg. */
00532 static bool checkreturn default_extension_decoder(pb_istream_t *stream,
00533     pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type)
00534 {
00535     const pb_field_t *field = (const pb_field_t*)extension->type->arg;
00536     pb_field_iterator_t iter;
00537     bool dummy;
00538     
00539     if (field->tag != tag)
00540         return true;
00541     
00542     iter.start = field;
00543     iter.pos = field;
00544     iter.field_index = 0;
00545     iter.required_field_index = 0;
00546     iter.dest_struct = extension->dest;
00547     iter.pData = extension->dest;
00548     iter.pSize = &dummy;
00549     
00550     return decode_field(stream, wire_type, &iter);
00551 }
00552 
00553 /* Try to decode an unknown field as an extension field. Tries each extension
00554  * decoder in turn, until one of them handles the field or loop ends. */
00555 static bool checkreturn decode_extension(pb_istream_t *stream,
00556     uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
00557 {
00558     pb_extension_t *extension = *(pb_extension_t* const *)iter->pData;
00559     size_t pos = stream->bytes_left;
00560     
00561     while (extension && pos == stream->bytes_left)
00562     {
00563         bool status;
00564         if (extension->type->decode)
00565             status = extension->type->decode(stream, extension, tag, wire_type);
00566         else
00567             status = default_extension_decoder(stream, extension, tag, wire_type);
00568 
00569         if (!status)
00570             return false;
00571         
00572         extension = extension->next;
00573     }
00574     
00575     return true;
00576 }
00577 
00578 /* Step through the iterator until an extension field is found or until all
00579  * entries have been checked. There can be only one extension field per
00580  * message. Returns false if no extension field is found. */
00581 static bool checkreturn find_extension_field(pb_field_iterator_t *iter)
00582 {
00583     unsigned start = iter->field_index;
00584     
00585     do {
00586         if (PB_LTYPE(iter->pos->type) == PB_LTYPE_EXTENSION)
00587             return true;
00588         pb_field_next(iter);
00589     } while (iter->field_index != start);
00590     
00591     return false;
00592 }
00593 
00594 /* Initialize message fields to default values, recursively */
00595 static void pb_message_set_to_defaults(const pb_field_t fields[], void *dest_struct)
00596 {
00597     pb_field_iterator_t iter;
00598     pb_field_init(&iter, fields, dest_struct);
00599     
00600     /* Initialize size/has fields and apply default values */
00601     do
00602     {
00603         pb_type_t type;
00604         type = iter.pos->type;
00605     
00606         if (iter.pos->tag == 0)
00607             continue;
00608         
00609         if (PB_ATYPE(type) == PB_ATYPE_STATIC)
00610         {
00611             /* Initialize the size field for optional/repeated fields to 0. */
00612             if (PB_HTYPE(type) == PB_HTYPE_OPTIONAL)
00613             {
00614                 *(bool*)iter.pSize = false;
00615             }
00616             else if (PB_HTYPE(type) == PB_HTYPE_REPEATED)
00617             {
00618                 *(size_t*)iter.pSize = 0;
00619                 continue; /* Array is empty, no need to initialize contents */
00620             }
00621             
00622             /* Initialize field contents to default value */
00623             if (PB_LTYPE(iter.pos->type) == PB_LTYPE_SUBMESSAGE)
00624             {
00625                 pb_message_set_to_defaults((const pb_field_t *) iter.pos->ptr, iter.pData);
00626             }
00627             else if (iter.pos->ptr != NULL)
00628             {
00629                 memcpy(iter.pData, iter.pos->ptr, iter.pos->data_size);
00630             }
00631             else
00632             {
00633                 memset(iter.pData, 0, iter.pos->data_size);
00634             }
00635         }
00636         else if (PB_ATYPE(type) == PB_ATYPE_CALLBACK)
00637         {
00638             continue; /* Don't overwrite callback */
00639         }
00640     } while (pb_field_next(&iter));
00641 }
00642 
00643 /*********************
00644  * Decode all fields *
00645  *********************/
00646 
00647 bool checkreturn pb_decode_noinit(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
00648 {
00649     uint8_t fields_seen[(PB_MAX_REQUIRED_FIELDS + 7) / 8] = {0}; /* Used to check for required fields */
00650     uint32_t extension_range_start = 0;
00651     pb_field_iterator_t iter;
00652     
00653     pb_field_init(&iter, fields, dest_struct);
00654     
00655     while (stream->bytes_left)
00656     {
00657         uint32_t tag;
00658         pb_wire_type_t wire_type;
00659         bool eof;
00660         
00661         if (!pb_decode_tag(stream, &wire_type, &tag, &eof))
00662         {
00663             if (eof)
00664                 break;
00665             else
00666                 return false;
00667         }
00668         
00669         if (!pb_field_find(&iter, tag))
00670         {
00671             /* No match found, check if it matches an extension. */
00672             if (tag >= extension_range_start)
00673             {
00674                 if (!find_extension_field(&iter))
00675                     extension_range_start = (uint32_t)-1;
00676                 else
00677                     extension_range_start = iter.pos->tag;
00678                 
00679                 if (tag >= extension_range_start)
00680                 {
00681                     size_t pos = stream->bytes_left;
00682                 
00683                     if (!decode_extension(stream, tag, wire_type, &iter))
00684                         return false;
00685                     
00686                     if (pos != stream->bytes_left)
00687                     {
00688                         /* The field was handled */
00689                         continue;                    
00690                     }
00691                 }
00692             }
00693         
00694             /* No match found, skip data */
00695             if (!pb_skip_field(stream, wire_type))
00696                 return false;
00697             continue;
00698         }
00699         
00700         if (PB_HTYPE(iter.pos->type) == PB_HTYPE_REQUIRED
00701             && iter.required_field_index < PB_MAX_REQUIRED_FIELDS)
00702         {
00703             fields_seen[iter.required_field_index >> 3] |= (uint8_t)(1 << (iter.required_field_index & 7));
00704         }
00705             
00706         if (!decode_field(stream, wire_type, &iter))
00707             return false;
00708     }
00709     
00710     /* Check that all required fields were present. */
00711     {
00712         /* First figure out the number of required fields by
00713          * seeking to the end of the field array. Usually we
00714          * are already close to end after decoding.
00715          */
00716         unsigned req_field_count;
00717         pb_type_t last_type;
00718         unsigned i;
00719         do {
00720             req_field_count = iter.required_field_index;
00721             last_type = iter.pos->type;
00722         } while (pb_field_next(&iter));
00723         
00724         /* Fixup if last field was also required. */
00725         if (PB_HTYPE(last_type) == PB_HTYPE_REQUIRED && iter.pos->tag)
00726             req_field_count++;
00727         
00728         /* Check the whole bytes */
00729         for (i = 0; i < (req_field_count >> 3); i++)
00730         {
00731             if (fields_seen[i] != 0xFF)
00732                 PB_RETURN_ERROR(stream, "missing required field");
00733         }
00734         
00735         /* Check the remaining bits */
00736         if (fields_seen[req_field_count >> 3] != (0xFF >> (8 - (req_field_count & 7))))
00737             PB_RETURN_ERROR(stream, "missing required field");
00738     }
00739     
00740     return true;
00741 }
00742 
00743 bool checkreturn pb_decode(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
00744 {
00745     pb_message_set_to_defaults(fields, dest_struct);
00746     return pb_decode_noinit(stream, fields, dest_struct);
00747 }
00748 
00749 bool pb_decode_delimited(pb_istream_t *stream, const pb_field_t fields[], void *dest_struct)
00750 {
00751     pb_istream_t substream;
00752     bool status;
00753     
00754     if (!pb_make_string_substream(stream, &substream))
00755         return false;
00756     
00757     status = pb_decode(&substream, fields, dest_struct);
00758     pb_close_string_substream(stream, &substream);
00759     return status;
00760 }
00761 
00762 /* Field decoders */
00763 
00764 bool pb_decode_svarint(pb_istream_t *stream, int64_t *dest)
00765 {
00766     uint64_t value;
00767     if (!pb_decode_varint(stream, &value))
00768         return false;
00769     
00770     if (value & 1)
00771         *dest = (int64_t)(~(value >> 1));
00772     else
00773         *dest = (int64_t)(value >> 1);
00774     
00775     return true;
00776 }
00777 
00778 bool pb_decode_fixed32(pb_istream_t *stream, void *dest)
00779 {
00780     #ifdef __BIG_ENDIAN__
00781     uint8_t *bytes = (uint8_t*)dest;
00782     uint8_t lebytes[4];
00783     
00784     if (!pb_read(stream, lebytes, 4))
00785         return false;
00786     
00787     bytes[0] = lebytes[3];
00788     bytes[1] = lebytes[2];
00789     bytes[2] = lebytes[1];
00790     bytes[3] = lebytes[0];
00791     return true;
00792     #else
00793     return pb_read(stream, (uint8_t*)dest, 4);
00794     #endif   
00795 }
00796 
00797 bool pb_decode_fixed64(pb_istream_t *stream, void *dest)
00798 {
00799     #ifdef __BIG_ENDIAN__
00800     uint8_t *bytes = (uint8_t*)dest;
00801     uint8_t lebytes[8];
00802     
00803     if (!pb_read(stream, lebytes, 8))
00804         return false;
00805     
00806     bytes[0] = lebytes[7];
00807     bytes[1] = lebytes[6];
00808     bytes[2] = lebytes[5];
00809     bytes[3] = lebytes[4];
00810     bytes[4] = lebytes[3];
00811     bytes[5] = lebytes[2];
00812     bytes[6] = lebytes[1];
00813     bytes[7] = lebytes[0];
00814     return true;
00815     #else
00816     return pb_read(stream, (uint8_t*)dest, 8);
00817     #endif   
00818 }
00819 
00820 bool checkreturn pb_dec_varint(pb_istream_t *stream, const pb_field_t *field, void *dest)
00821 {
00822     uint64_t value;
00823     if (!pb_decode_varint(stream, &value))
00824         return false;
00825     
00826     switch (field->data_size)
00827     {
00828         case 1: *(int8_t*)dest = (int8_t)value; break;
00829         case 2: *(int16_t*)dest = (int16_t)value; break;
00830         case 4: *(int32_t*)dest = (int32_t)value; break;
00831         case 8: *(int64_t*)dest = (int64_t)value; break;
00832         default: PB_RETURN_ERROR(stream, "invalid data_size");
00833     }
00834     
00835     return true;
00836 }
00837 
00838 bool checkreturn pb_dec_uvarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
00839 {
00840     uint64_t value;
00841     if (!pb_decode_varint(stream, &value))
00842         return false;
00843     
00844     switch (field->data_size)
00845     {
00846         case 4: *(uint32_t*)dest = (uint32_t)value; break;
00847         case 8: *(uint64_t*)dest = value; break;
00848         default: PB_RETURN_ERROR(stream, "invalid data_size");
00849     }
00850     
00851     return true;
00852 }
00853 
00854 bool checkreturn pb_dec_svarint(pb_istream_t *stream, const pb_field_t *field, void *dest)
00855 {
00856     int64_t value;
00857     if (!pb_decode_svarint(stream, &value))
00858         return false;
00859     
00860     switch (field->data_size)
00861     {
00862         case 4: *(int32_t*)dest = (int32_t)value; break;
00863         case 8: *(int64_t*)dest = value; break;
00864         default: PB_RETURN_ERROR(stream, "invalid data_size");
00865     }
00866     
00867     return true;
00868 }
00869 
00870 bool checkreturn pb_dec_fixed32(pb_istream_t *stream, const pb_field_t *field, void *dest)
00871 {
00872     UNUSED(field);
00873     return pb_decode_fixed32(stream, dest);
00874 }
00875 
00876 bool checkreturn pb_dec_fixed64(pb_istream_t *stream, const pb_field_t *field, void *dest)
00877 {
00878     UNUSED(field);
00879     return pb_decode_fixed64(stream, dest);
00880 }
00881 
00882 bool checkreturn pb_dec_bytes(pb_istream_t *stream, const pb_field_t *field, void *dest)
00883 {
00884     pb_bytes_array_t *x = (pb_bytes_array_t*)dest;
00885     
00886     uint32_t temp;
00887     if (!pb_decode_varint32(stream, &temp))
00888         return false;
00889     x->size = temp;
00890     
00891     /* Check length, noting the space taken by the size_t header. */
00892     if (x->size > field->data_size - offsetof(pb_bytes_array_t, bytes))
00893         PB_RETURN_ERROR(stream, "bytes overflow");
00894     
00895     return pb_read(stream, x->bytes, x->size);
00896 }
00897 
00898 bool checkreturn pb_dec_string(pb_istream_t *stream, const pb_field_t *field, void *dest)
00899 {
00900     uint32_t size;
00901     bool status;
00902     if (!pb_decode_varint32(stream, &size))
00903         return false;
00904     
00905     /* Check length, noting the null terminator */
00906     if (size + 1 > field->data_size)
00907         PB_RETURN_ERROR(stream, "string overflow");
00908     
00909     status = pb_read(stream, (uint8_t*)dest, size);
00910     *((uint8_t*)dest + size) = 0;
00911     return status;
00912 }
00913 
00914 bool checkreturn pb_dec_submessage(pb_istream_t *stream, const pb_field_t *field, void *dest)
00915 {
00916     bool status;
00917     pb_istream_t substream;
00918     const pb_field_t* submsg_fields = (const pb_field_t*)field->ptr;
00919     
00920     if (!pb_make_string_substream(stream, &substream))
00921         return false;
00922     
00923     if (field->ptr == NULL)
00924         PB_RETURN_ERROR(stream, "invalid field descriptor");
00925     
00926     /* New array entries need to be initialized, while required and optional
00927      * submessages have already been initialized in the top-level pb_decode. */
00928     if (PB_HTYPE(field->type) == PB_HTYPE_REPEATED)
00929         status = pb_decode(&substream, submsg_fields, dest);
00930     else
00931         status = pb_decode_noinit(&substream, submsg_fields, dest);
00932     
00933     pb_close_string_substream(stream, &substream);
00934     return status;
00935 }
00936