snarkvm_console_program/data/identifier/
from_bits.rs

1// Copyright 2024-2025 Aleo Network Foundation
2// This file is part of the snarkVM 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
16use super::*;
17
18impl<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)]
47mod tests {
48    use super::*;
49    use crate::data::identifier::tests::sample_identifier;
50    use snarkvm_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}
snarkvm_console_program/data/identifier/from_bits.rs

snarkvm_console_program/data/identifier/
from_bits.rs
