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<E: Environment> FromBytes for StringType<E> {
19      /// Reads the string from a buffer.
20      #[inline]
21      fn read_le<R: Read>(mut reader: R) -> IoResult<Self> {
22          // Read the number of bytes.
23          let num_bytes = u16::read_le(&mut reader)?;
24          // Ensure the number of bytes is within the allowed bounds.
25          if num_bytes as u32 > E::MAX_STRING_BYTES {
26              return Err(error(format!("String literal exceeds maximum length of {} bytes.", E::MAX_STRING_BYTES)));
27          }
28          // Read the bytes.
29          let mut bytes = vec![0u8; num_bytes as usize];
30          reader.read_exact(&mut bytes)?;
31          // Return the string.
32          Ok(Self::new(&String::from_utf8(bytes).map_err(error)?))
33      }
34  }
35  
36  impl<E: Environment> ToBytes for StringType<E> {
37      /// Writes the string to a buffer.
38      #[inline]
39      fn write_le<W: Write>(&self, mut writer: W) -> IoResult<()> {
40          // Ensure the number of bytes is within the allowed bounds.
41          if self.string.len() > E::MAX_STRING_BYTES as usize {
42              return Err(error(format!("String literal exceeds maximum length of {} bytes.", E::MAX_STRING_BYTES)));
43          }
44          // Write the number of bytes.
45          u16::try_from(self.string.len()).or_halt_with::<E>("String exceeds u16::MAX bytes").write_le(&mut writer)?;
46          // Write the bytes.
47          self.string.as_bytes().write_le(&mut writer)
48      }
49  }
50  
51  #[cfg(test)]
52  mod tests {
53      use super::*;
54      use alphavm_console_network_environment::Console;
55  
56      type CurrentEnvironment = Console;
57  
58      const ITERATIONS: u64 = 10_000;
59  
60      #[test]
61      fn test_bytes() -> Result<()> {
62          let mut rng = TestRng::default();
63  
64          for _ in 0..ITERATIONS {
65              // Sample a new string.
66              let expected = StringType::<CurrentEnvironment>::rand(&mut rng);
67  
68              // Check the byte representation.
69              let expected_bytes = expected.to_bytes_le()?;
70              assert_eq!(expected, StringType::read_le(&expected_bytes[..])?);
71          }
72          Ok(())
73      }
74  }