1  // Copyright (c) 2019-2025 Alpha-Delta Network Inc.
 2  // This file is part of the alphavm 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<N: Network> FromBytes for Identifier<N> {
19      /// Reads in an identifier from a buffer.
20      fn read_le<R: Read>(mut reader: R) -> IoResult<Self> {
21          // Read the number of bytes.
22          let size = u8::read_le(&mut reader)?;
23  
24          // Read the identifier bytes.
25          let mut buffer = vec![0u8; size as usize];
26          reader.read_exact(&mut buffer)?;
27  
28          // from_str the identifier.
29          // Note: `Self::from_str` ensures that the identifier string is not empty.
30          Self::from_str(&String::from_utf8(buffer).map_err(|e| error(format!("Failed to decode identifier: {e}")))?)
31              .map_err(|e| error(format!("{e}")))
32      }
33  }
34  
35  impl<N: Network> ToBytes for Identifier<N> {
36      /// Writes an identifier to a buffer.
37      fn write_le<W: Write>(&self, mut writer: W) -> IoResult<()> {
38          // Convert the identifier to a string.
39          let string = self.to_string();
40          if string.len() != self.1 as usize {
41              return Err(error("Identifier length does not match expected size"));
42          }
43  
44          // Ensure identifier fits within the data capacity of the base field.
45          let max_bytes = Field::<N>::size_in_data_bits() / 8; // Note: This intentionally rounds down.
46          if string.len() > max_bytes {
47              return Err(error(format!("Identifier is too large. Identifiers must be <= {max_bytes} bytes long")));
48          }
49  
50          // Write the identifier to a buffer.
51          u8::try_from(string.len()).or_halt_with::<N>("Invalid identifier length").write_le(&mut writer)?;
52          string.as_bytes().write_le(&mut writer)
53      }
54  }
55  
56  #[cfg(test)]
57  mod tests {
58      use super::*;
59      use crate::data::identifier::tests::sample_identifier;
60      use alphavm_console_network::MainnetV0;
61  
62      type CurrentNetwork = MainnetV0;
63  
64      const ITERATIONS: u64 = 1000;
65  
66      #[test]
67      fn test_bytes() -> Result<()> {
68          let mut rng = TestRng::default();
69  
70          for _ in 0..ITERATIONS {
71              // Sample a random fixed-length alphanumeric identifier, that always starts with an alphabetic character.
72              let expected = sample_identifier::<CurrentNetwork>(&mut rng)?;
73  
74              // Check the byte representation.
75              let expected_bytes = expected.to_bytes_le()?;
76              assert_eq!(expected, Identifier::read_le(&expected_bytes[..])?);
77          }
78          Ok(())
79      }
80  
81      #[test]
82      fn test_zero_identifier_fails() {
83          assert!(Identifier::<CurrentNetwork>::read_le(&[0u8; 1][..]).is_err())
84      }
85  }