1use super::{utils::string::String, Word};
  2use core::fmt::{self, Display, Write};
  3
  4#[cfg(not(feature = "std"))]
  5pub use alloc::{format, vec};
  6
  7#[cfg(feature = "std")]
  8pub use std::{format, vec};
  9
 10mod diff;
 11mod kv_map;
 12
 13// RE-EXPORTS
 14// ================================================================================================
 15pub use winter_utils::{
 16    string, uninit_vector, Box, ByteReader, ByteWriter, Deserializable, DeserializationError,
 17    Serializable, SliceReader,
 18};
 19
 20pub mod collections {
 21    pub use super::diff::*;
 22    pub use super::kv_map::*;
 23    pub use winter_utils::collections::*;
 24}
 25
 26// UTILITY FUNCTIONS
 27// ================================================================================================
 28
 29/// Converts a [Word] into hex.
 30pub fn word_to_hex(w: &Word) -> Result<String, fmt::Error> {
 31    let mut s = String::new();
 32
 33    for byte in w.iter().flat_map(|e| e.to_bytes()) {
 34        write!(s, "{byte:02x}")?;
 35    }
 36
 37    Ok(s)
 38}
 39
 40/// Renders an array of bytes as hex into a String.
 41pub fn bytes_to_hex_string<const N: usize>(data: [u8; N]) -> String {
 42    let mut s = String::with_capacity(N + 2);
 43
 44    s.push_str("0x");
 45    for byte in data.iter() {
 46        write!(s, "{byte:02x}").expect("formatting hex failed");
 47    }
 48
 49    s
 50}
 51
 52#[derive(Debug)]
 53pub enum HexParseError {
 54    InvalidLength { expected: usize, got: usize },
 55    MissingPrefix,
 56    InvalidChar,
 57    OutOfRange,
 58}
 59
 60impl Display for HexParseError {
 61    fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
 62        match self {
 63            HexParseError::InvalidLength { expected, got } => {
 64                write!(f, "Hex encoded RpoDigest must have length 66, including the 0x prefix. expected {expected} got {got}")
 65            }
 66            HexParseError::MissingPrefix => {
 67                write!(f, "Hex encoded RpoDigest must start with 0x prefix")
 68            }
 69            HexParseError::InvalidChar => {
 70                write!(f, "Hex encoded RpoDigest must contain characters [a-zA-Z0-9]")
 71            }
 72            HexParseError::OutOfRange => {
 73                write!(f, "Hex encoded values of an RpoDigest must be inside the field modulus")
 74            }
 75        }
 76    }
 77}
 78
 79#[cfg(feature = "std")]
 80impl std::error::Error for HexParseError {}
 81
 82/// Parses a hex string into an array of bytes of known size.
 83pub fn hex_to_bytes<const N: usize>(value: &str) -> Result<[u8; N], HexParseError> {
 84    let expected: usize = (N * 2) + 2;
 85    if value.len() != expected {
 86        return Err(HexParseError::InvalidLength {
 87            expected,
 88            got: value.len(),
 89        });
 90    }
 91
 92    if !value.starts_with("0x") {
 93        return Err(HexParseError::MissingPrefix);
 94    }
 95
 96    let mut data = value.bytes().skip(2).map(|v| match v {
 97        b'0'..=b'9' => Ok(v - b'0'),
 98        b'a'..=b'f' => Ok(v - b'a' + 10),
 99        b'A'..=b'F' => Ok(v - b'A' + 10),
100        _ => Err(HexParseError::InvalidChar),
101    });
102
103    let mut decoded = [0u8; N];
104    #[allow(clippy::needless_range_loop)]
105    for pos in 0..N {
106        // These `unwrap` calls are okay because the length was checked above
107        let high: u8 = data.next().unwrap()?;
108        let low: u8 = data.next().unwrap()?;
109        decoded[pos] = (high << 4) + low;
110    }
111
112    Ok(decoded)
113}