//
// Copyright 2019 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//

// This file defines the input/output data format accepted by the differentially
// private algorithms.

syntax = "proto2";

package differential_privacy;

import "proto/confidence-interval.proto";

option java_package = "com.google.privacy.differentialprivacy.proto";

// Defining our own value type to restrict the acceptable data types.
// It would change as per the future extensions.
message ValueType {
  oneof value {
    int64 int_value = 1;
    double float_value = 2;
    string string_value = 3;
  }
}

// Output data produced by a differentially private algorithm.
message Output {
  message Element {
    // Diff. priv. result of the operation performed over the input data.
    optional ValueType value = 1;
    // DEPRECATED: Use Element.noise_confidence_interval instead.
    optional ValueType error = 2 [deprecated = true];
    // Confidence interval of the noise added to the result
    optional ConfidenceInterval noise_confidence_interval = 3;
  }
  repeated Element elements = 1;

  // Contains information about algorithm accuracy.
  message ErrorReport {
    // DEPRECATED: Use Element.noise_confidence_interval instead.
    optional ConfidenceInterval noise_confidence_interval = 1
        [deprecated = true];
    optional BoundingReport bounding_report = 2;
  }
  // Error report is attached if either the noise confidence interval or the
  // bounding report is available.
  optional ErrorReport error_report = 3;

  reserved 2;
}

// Accuracy information about results of automatic bounding algorithms.
// When ApproxBounds is called by bounded algorithms, the BoundingReport can
// be used to pass differentially private intermediate results to help users
// understand the accuracy implications of the output.
message BoundingReport {
  // Lower and upper bounds produced by the ApproxBounds algorithm.
  optional ValueType lower_bound = 1;
  optional ValueType upper_bound = 2;

  // Noisy number of total inputs to the bounding algorithm.
  optional double num_inputs = 3;

  // Noisy number of inputs lying outside the bounds.
  optional double num_outside = 4;
}