NanoPB encode & decode repeated int32_t values

Question

I have a problem when I encode my int array into a message and then decode it in my C# application. When I decode my int array, I get send the encoded bytes to C# by MQTT. I decode it there and all my values are doubled there. I then send the same bytes immidiately back to the NanoPB application where it gets decoded as well, all the values are normal here. What is going on?

My protofile:

syntax = "proto2";

message stringCallback{
    required string name = 1;
    required string surname = 2;
    required int32 age = 3;
    repeated int32 values = 4;
}

My NanoPB encode function:

bool IntArray_encode(pb_ostream_t *ostream, const pb_field_t *field, void* const* arg){
  IntArray* arr = (IntArray*)*arg;
  
  for(int i = 0; i < arr->count; i++){
    if(!pb_encode_tag_for_field(ostream, field)){
      Serial.println("Encoding failed!");
      return false;
    }

    if(!pb_encode_svarint(ostream, arr->values[i])){
      Serial.println("Encoding failed!");
      return false;
    }
  }

  return true;
}

My NanoPB decode function:

bool IntArray_decode(pb_istream_t *stream, const pb_field_t *field, void** arg){
  IntArray* arr = (IntArray*)*arg;
  int64_t number;

  if(!pb_decode_svarint(stream, &number)){
    Serial.println("Decoding failed!");
    return false;
  }

  Serial.println(number);
  IntArray_add(arr, (int32_t)number);

  return true;
}

Output NanoPB:

Name = Testing
Surname = Purpose
Age = 23
[14 11 10 5 109 32321 23 19 15]

Output C#:

Name = Testing
Surname = Purpose
Age = 23
[28 22 20 10 218 64642 46 38 30 ]

Answer 1

if(,pb_encode_svarint(ostream, arr->values[i])){

The pb_encode_svarint() function is for sint32 and sint64 types.

Your .proto file specifies int32 so you should use pb_encode_varint() .