neo-decompiler 0.10.2

use std::fmt;

use ripemd::Ripemd160;
use sha2::{Digest, Sha256};

/// Write the provided bytes as uppercase hexadecimal into the supplied formatter.
pub(crate) fn write_upper_hex(f: &mut fmt::Formatter<'_>, bytes: &[u8]) -> fmt::Result {
    f.write_str(&hex::encode_upper(bytes))
}

/// Return the provided bytes encoded as an uppercase hexadecimal string.
pub(crate) fn upper_hex_string(bytes: &[u8]) -> String {
    hex::encode_upper(bytes)
}

/// Convenience helper used when rendering script hashes or method token hashes.
pub(crate) fn format_hash(bytes: &[u8]) -> String {
    upper_hex_string(bytes)
}

/// Return the provided bytes encoded as uppercase hexadecimal after flipping endianness.
pub(crate) fn format_hash_be(bytes: &[u8]) -> String {
    let mut reversed = bytes.to_vec();
    reversed.reverse();
    upper_hex_string(&reversed)
}

/// Compute the Neo Hash160 (`RIPEMD160(SHA256(data))`) and return the
/// little-endian bytes.
///
/// The raw `RIPEMD160(SHA256(..))` digest IS Neo's internal little-endian
/// `UInt160` byte order — the explorer/display ("big-endian", `0x`-prefixed)
/// form is this digest reversed. So the digest is returned as-is: callers use
/// [`format_hash`] for the little-endian rendering and [`format_hash_be`] for
/// the display rendering. (Reversing here would invert both, which is exactly
/// the bug this comment exists to prevent.)
pub(crate) fn hash160(data: &[u8]) -> [u8; 20] {
    let sha = Sha256::digest(data);
    let ripemd = Ripemd160::digest(sha);
    let mut output = [0u8; 20];
    output.copy_from_slice(&ripemd);
    output
}

#[cfg(test)]
mod tests;