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> FromBits for Identifier<N> {
19      /// Initializes a new identifier from a list of little-endian bits *without* trailing zeros.
20      fn from_bits_le(bits_le: &[bool]) -> Result<Self> {
21          // Ensure the number of bits does not exceed the size in bits of the field.
22          // This check is not sufficient to ensure the identifier is of valid size,
23          // the final step checks the byte-aligned field element is within the data capacity.
24          ensure!(bits_le.len() <= Field::<N>::size_in_bits(), "Identifier exceeds the maximum bits allowed");
25  
26          // Convert the bits to bytes, and parse the bytes as a UTF-8 string.
27          let bytes = bits_le.chunks(8).map(u8::from_bits_le).collect::<Result<Vec<u8>>>()?;
28  
29          // Recover the identifier length from the bits, by finding the first instance of a `0` byte,
30          // which is the null character '\0' in UTF-8, and an invalid character in an identifier.
31          let num_bytes = match bytes.iter().position(|&byte| byte == 0) {
32              Some(index) => index, // `index` is 0-indexed, and we exclude the null character.
33              None => bytes.len(),  // No null character found, so the identifier is the full length.
34          };
35  
36          // Parse the bytes as a UTF-8 string.
37          Self::from_str(str::from_utf8(&bytes[0..num_bytes])?)
38      }
39  
40      /// Initializes a new identifier from a list of big-endian bits *without* leading zeros.
41      fn from_bits_be(bits_be: &[bool]) -> Result<Self> {
42          Self::from_bits_le(&bits_be.iter().rev().copied().collect::<Vec<bool>>())
43      }
44  }
45  
46  #[cfg(test)]
47  mod tests {
48      use super::*;
49      use crate::data::identifier::tests::sample_identifier;
50      use alphavm_console_network::MainnetV0;
51  
52      type CurrentNetwork = MainnetV0;
53  
54      const ITERATIONS: usize = 100;
55  
56      #[test]
57      fn test_from_bits_le() -> Result<()> {
58          let mut rng = TestRng::default();
59  
60          for _ in 0..ITERATIONS {
61              // Sample a random fixed-length alphanumeric identifier, that always starts with an alphabetic character.
62              let identifier = sample_identifier::<CurrentNetwork>(&mut rng)?;
63              assert_eq!(identifier, Identifier::from_bits_le(&identifier.to_bits_le())?);
64          }
65          Ok(())
66      }
67  
68      #[test]
69      fn test_from_bits_be() -> Result<()> {
70          let mut rng = TestRng::default();
71  
72          for _ in 0..ITERATIONS {
73              // Sample a random fixed-length alphanumeric identifier, that always starts with an alphabetic character.
74              let identifier = sample_identifier::<CurrentNetwork>(&mut rng)?;
75              assert_eq!(identifier, Identifier::from_bits_be(&identifier.to_bits_be())?);
76          }
77          Ok(())
78      }
79  }