// Copyright 2021 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.

syntax = "proto3";

package google.type;

option cc_enable_arenas = true;
option go_package = "google.golang.org/genproto/googleapis/type/decimal;decimal";
option java_multiple_files = true;
option java_outer_classname = "DecimalProto";
option java_package = "com.google.type";
option objc_class_prefix = "GTP";

// A representation of a decimal value, such as 2.5. Clients may convert values
// into language-native decimal formats, such as Java's [BigDecimal][] or
// Python's [decimal.Decimal][].
//
// [BigDecimal]:
// https://docs.oracle.com/en/java/javase/11/docs/api/java.base/java/math/BigDecimal.html
// [decimal.Decimal]: https://docs.python.org/3/library/decimal.html
message Decimal {
  // The decimal value, as a string.
  //
  // The string representation consists of an optional sign, `+` (`U+002B`)
  // or `-` (`U+002D`), followed by a sequence of zero or more decimal digits
  // ("the integer"), optionally followed by a fraction, optionally followed
  // by an exponent.
  //
  // The fraction consists of a decimal point followed by zero or more decimal
  // digits. The string must contain at least one digit in either the integer
  // or the fraction. The number formed by the sign, the integer and the
  // fraction is referred to as the significand.
  //
  // The exponent consists of the character `e` (`U+0065`) or `E` (`U+0045`)
  // followed by one or more decimal digits.
  //
  // Services **should** normalize decimal values before storing them by:
  //
  //   - Removing an explicitly-provided `+` sign (`+2.5` -> `2.5`).
  //   - Replacing a zero-length integer value with `0` (`.5` -> `0.5`).
  //   - Coercing the exponent character to lower-case (`2.5E8` -> `2.5e8`).
  //   - Removing an explicitly-provided zero exponent (`2.5e0` -> `2.5`).
  //
  // Services **may** perform additional normalization based on its own needs
  // and the internal decimal implementation selected, such as shifting the
  // decimal point and exponent value together (example: `2.5e-1` <-> `0.25`).
  // Additionally, services **may** preserve trailing zeroes in the fraction
  // to indicate increased precision, but are not required to do so.
  //
  // Note that only the `.` character is supported to divide the integer
  // and the fraction; `,` **should not** be supported regardless of locale.
  // Additionally, thousand separators **should not** be supported. If a
  // service does support them, values **must** be normalized.
  //
  // The ENBF grammar is:
  //
  //     DecimalString =
  //       [Sign] Significand [Exponent];
  //
  //     Sign = '+' | '-';
  //
  //     Significand =
  //       Digits ['.'] [Digits] | [Digits] '.' Digits;
  //
  //     Exponent = ('e' | 'E') [Sign] Digits;
  //
  //     Digits = { '0' | '1' | '2' | '3' | '4' | '5' | '6' | '7' | '8' | '9' };
  //
  // Services **should** clearly document the range of supported values, the
  // maximum supported precision (total number of digits), and, if applicable,
  // the scale (number of digits after the decimal point), as well as how it
  // behaves when receiving out-of-bounds values.
  //
  // Services **may** choose to accept values passed as input even when the
  // value has a higher precision or scale than the service supports, and
  // **should** round the value to fit the supported scale. Alternatively, the
  // service **may** error with `400 Bad Request` (`INVALID_ARGUMENT` in gRPC)
  // if precision would be lost.
  //
  // Services **should** error with `400 Bad Request` (`INVALID_ARGUMENT` in
  // gRPC) if the service receives a value outside of the supported range.
  string value = 1;
}
