+ iter->pos = iter->start;
+ iter->field_index = 0;
+ iter->required_field_index = 0;
+ iter->pData = iter->dest_struct;
+ prev_size = 0;
+ notwrapped = false;
+ }
+
+ iter->pData = (char*)iter->pData + prev_size + iter->pos->data_offset;
+ iter->pSize = (char*)iter->pData + iter->pos->size_offset;
+ return notwrapped;
+}
+
+static bool checkreturn pb_field_find(pb_field_iterator_t *iter, uint32_t tag)
+{
+ unsigned start = iter->field_index;
+
+ do {
+ if (iter->pos->tag == tag &&
+ PB_LTYPE(iter->pos->type) != PB_LTYPE_EXTENSION)
+ {
+ return true;
+ }
+ pb_field_next(iter);
+ } while (iter->field_index != start);
+
+ return false;
+}
+
+/*************************
+ * Decode a single field *
+ *************************/
+
+static bool checkreturn decode_static_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+{
+ pb_type_t type;
+ pb_decoder_t func;
+
+ type = iter->pos->type;
+ func = PB_DECODERS[PB_LTYPE(type)];
+
+ switch (PB_HTYPE(type))
+ {
+ case PB_HTYPE_REQUIRED:
+ return func(stream, iter->pos, iter->pData);
+
+ case PB_HTYPE_OPTIONAL:
+ *(bool*)iter->pSize = true;
+ return func(stream, iter->pos, iter->pData);
+
+ case PB_HTYPE_REPEATED:
+ if (wire_type == PB_WT_STRING
+ && PB_LTYPE(type) <= PB_LTYPE_LAST_PACKABLE)
+ {
+ /* Packed array */
+ bool status = true;
+ size_t *size = (size_t*)iter->pSize;
+ pb_istream_t substream;
+ if (!pb_make_string_substream(stream, &substream))
+ return false;
+
+ while (substream.bytes_left && *size < iter->pos->array_size)
+ {
+ void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
+ if (!func(&substream, iter->pos, pItem))
+ {
+ status = false;
+ break;
+ }
+ (*size)++;
+ }
+ pb_close_string_substream(stream, &substream);
+
+ if (substream.bytes_left != 0)
+ PB_RETURN_ERROR(stream, "array overflow");
+
+ return status;
+ }
+ else
+ {
+ /* Repeated field */
+ size_t *size = (size_t*)iter->pSize;
+ void *pItem = (uint8_t*)iter->pData + iter->pos->data_size * (*size);
+ if (*size >= iter->pos->array_size)
+ PB_RETURN_ERROR(stream, "array overflow");
+
+ (*size)++;
+ return func(stream, iter->pos, pItem);
+ }
+
+ default:
+ PB_RETURN_ERROR(stream, "invalid field type");
+ }
+}
+
+static bool checkreturn decode_callback_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+{
+ pb_callback_t *pCallback = (pb_callback_t*)iter->pData;
+
+#ifdef PB_OLD_CALLBACK_STYLE
+ void *arg = pCallback->arg;
+#else
+ void **arg = &(pCallback->arg);
+#endif
+
+ if (pCallback->funcs.decode == NULL)
+ return pb_skip_field(stream, wire_type);
+
+ if (wire_type == PB_WT_STRING)
+ {
+ pb_istream_t substream;
+
+ if (!pb_make_string_substream(stream, &substream))
+ return false;
+
+ do
+ {
+ if (!pCallback->funcs.decode(&substream, iter->pos, arg))
+ PB_RETURN_ERROR(stream, "callback failed");
+ } while (substream.bytes_left);
+
+ pb_close_string_substream(stream, &substream);
+ return true;
+ }
+ else
+ {
+ /* Copy the single scalar value to stack.
+ * This is required so that we can limit the stream length,
+ * which in turn allows to use same callback for packed and
+ * not-packed fields. */
+ pb_istream_t substream;
+ uint8_t buffer[10];
+ size_t size = sizeof(buffer);
+
+ if (!read_raw_value(stream, wire_type, buffer, &size))
+ return false;
+ substream = pb_istream_from_buffer(buffer, size);
+
+ return pCallback->funcs.decode(&substream, iter->pos, arg);
+ }
+}
+
+static bool checkreturn decode_field(pb_istream_t *stream, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+{
+ switch (PB_ATYPE(iter->pos->type))
+ {
+ case PB_ATYPE_STATIC:
+ return decode_static_field(stream, wire_type, iter);
+
+ case PB_ATYPE_CALLBACK:
+ return decode_callback_field(stream, wire_type, iter);
+
+ default:
+ PB_RETURN_ERROR(stream, "invalid field type");
+ }
+}
+
+/* Default handler for extension fields. Expects a pb_field_t structure
+ * in extension->type->arg. */
+static bool checkreturn default_extension_handler(pb_istream_t *stream,
+ pb_extension_t *extension, uint32_t tag, pb_wire_type_t wire_type)
+{
+ const pb_field_t *field = (const pb_field_t*)extension->type->arg;
+ pb_field_iterator_t iter;
+ bool dummy;
+
+ if (field->tag != tag)
+ return true;
+
+ iter.start = field;
+ iter.pos = field;
+ iter.field_index = 0;
+ iter.required_field_index = 0;
+ iter.dest_struct = extension->dest;
+ iter.pData = extension->dest;
+ iter.pSize = &dummy;
+
+ return decode_field(stream, wire_type, &iter);
+}
+
+/* Try to decode an unknown field as an extension field. Tries each extension
+ * decoder in turn, until one of them handles the field or loop ends. */
+static bool checkreturn decode_extension(pb_istream_t *stream,
+ uint32_t tag, pb_wire_type_t wire_type, pb_field_iterator_t *iter)
+{
+ pb_extension_t *extension = *(pb_extension_t* const *)iter->pData;
+ size_t pos = stream->bytes_left;
+
+ while (extension && pos == stream->bytes_left)
+ {
+ bool status;
+ if (extension->type->decode)
+ status = extension->type->decode(stream, extension, tag, wire_type);
+ else
+ status = default_extension_handler(stream, extension, tag, wire_type);
+
+ if (!status)