1  // Copyright (c) 2019-2025 Alpha-Delta Network Inc.
  2  // This file is part of the deltavm library.
  3  
  4  // Licensed under the Apache License, Version 2.0 (the "License");
  5  // you may not use this file except in compliance with the License.
  6  // You may obtain a copy of the License at:
  7  
  8  // http://www.apache.org/licenses/LICENSE-2.0
  9  
 10  // Unless required by applicable law or agreed to in writing, software
 11  // distributed under the License is distributed on an "AS IS" BASIS,
 12  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 13  // See the License for the specific language governing permissions and
 14  // limitations under the License.
 15  
 16  use super::*;
 17  
 18  impl<E: Environment> Parser for Group<E> {
 19      /// Parses a string into a group circuit.
 20      #[inline]
 21      fn parse(string: &str) -> ParserResult<Self> {
 22          // Parse the optional negative sign '-' from the string.
 23          let (string, negation) = map(opt(tag("-")), |neg: Option<&str>| neg.is_some())(string)?;
 24          // Parse the digits from the string.
 25          let (string, primitive) = recognize(many1(terminated(one_of("0123456789"), many0(char('_')))))(string)?;
 26          // Parse the group from the string.
 27          let (string, group): (&str, Self) = map_res(tag(Self::type_name()), |_| {
 28              let x_coordinate = primitive.replace('_', "").parse()?;
 29              // Recover and negate the group element if the negative sign was present.
 30              match negation {
 31                  true => Ok(-Group::from_x_coordinate(Field::new(x_coordinate))?),
 32                  false => Group::from_x_coordinate(Field::new(x_coordinate)),
 33              }
 34          })(string)?;
 35  
 36          Ok((string, group))
 37      }
 38  }
 39  
 40  impl<E: Environment> FromStr for Group<E> {
 41      type Err = Error;
 42  
 43      /// Parses a string into a group.
 44      #[inline]
 45      fn from_str(string: &str) -> Result<Self> {
 46          match Self::parse(string) {
 47              Ok((remainder, object)) => {
 48                  // Ensure the remainder is empty.
 49                  ensure!(remainder.is_empty(), "Failed to parse string. Found invalid character in: \"{remainder}\"");
 50                  // Return the object.
 51                  Ok(object)
 52              }
 53              Err(error) => bail!("Failed to parse string. {error}"),
 54          }
 55      }
 56  }
 57  
 58  impl<E: Environment> Debug for Group<E> {
 59      fn fmt(&self, f: &mut Formatter) -> fmt::Result {
 60          Display::fmt(self, f)
 61      }
 62  }
 63  
 64  impl<E: Environment> Display for Group<E> {
 65      fn fmt(&self, f: &mut Formatter) -> fmt::Result {
 66          write!(f, "{}{}", self.group.to_affine().to_x_coordinate(), Self::type_name())
 67      }
 68  }
 69  
 70  #[cfg(test)]
 71  mod tests {
 72      use super::*;
 73      use deltavm_console_network_environment::Console;
 74  
 75      type CurrentEnvironment = Console;
 76  
 77      const ITERATIONS: u64 = 1_000;
 78  
 79      #[test]
 80      fn test_parse() -> Result<()> {
 81          let rng = &mut TestRng::default();
 82  
 83          // Ensure empty value fails.
 84          assert!(Group::<CurrentEnvironment>::parse(Group::<CurrentEnvironment>::type_name()).is_err());
 85          assert!(Group::<CurrentEnvironment>::parse("").is_err());
 86  
 87          for _ in 0..ITERATIONS {
 88              // Sample a random value.
 89              let group: <CurrentEnvironment as Environment>::Affine = Uniform::rand(rng);
 90  
 91              let expected = format!("{}{}", group.to_x_coordinate(), Group::<CurrentEnvironment>::type_name());
 92              let (remainder, candidate) = Group::<CurrentEnvironment>::parse(&expected).unwrap();
 93              assert_eq!(format!("{expected}"), candidate.to_string());
 94              assert_eq!("", remainder);
 95          }
 96          Ok(())
 97      }
 98  
 99      #[test]
100      fn test_display() {
101          /// Attempts to construct a group from the given element,
102          /// format it in display mode, and recover a group from it.
103          fn check_display<E: Environment>(element: E::Affine) {
104              let candidate = Group::<E>::new(element);
105              assert_eq!(format!("{}{}", element.to_x_coordinate(), Group::<E>::type_name()), format!("{candidate}"));
106  
107              let candidate_recovered = Group::<E>::from_str(&format!("{candidate}")).unwrap();
108              assert_eq!(candidate, candidate_recovered);
109          }
110  
111          let mut rng = TestRng::default();
112  
113          for _ in 0..ITERATIONS {
114              let element = Uniform::rand(&mut rng);
115  
116              check_display::<CurrentEnvironment>(element);
117          }
118      }
119  
120      #[test]
121      fn test_display_zero() {
122          let zero = <CurrentEnvironment as Environment>::Affine::zero();
123  
124          let candidate = Group::<CurrentEnvironment>::new(zero);
125          assert_eq!("0group", &format!("{candidate}"));
126      }
127  }