78 lines
1.8 KiB
Rust
78 lines
1.8 KiB
Rust
use hex;
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use hex::ToHex;
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use serde::de::{self, Visitor};
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use std::fmt;
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pub fn encode<T: AsRef<[u8]>>(data: T) -> String {
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let mut hex = String::with_capacity(data.as_ref().len() * 2);
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// Writing to a string never errors, so we can unwrap here.
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data.write_hex(&mut hex).unwrap();
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let mut s = "0x".to_string();
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s.push_str(hex.as_str());
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s
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}
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pub struct PrefixedHexVisitor;
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impl<'de> Visitor<'de> for PrefixedHexVisitor {
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type Value = Vec<u8>;
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fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
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formatter.write_str("a hex string with 0x prefix")
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}
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fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
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where
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E: de::Error,
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{
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if value.starts_with("0x") {
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Ok(hex::decode(&value[2..])
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.map_err(|e| de::Error::custom(format!("invalid hex ({:?})", e)))?)
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} else {
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Err(de::Error::custom("missing 0x prefix"))
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}
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}
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}
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pub struct HexVisitor;
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impl<'de> Visitor<'de> for HexVisitor {
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type Value = Vec<u8>;
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fn expecting(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
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formatter.write_str("a hex string (irrelevant of prefix)")
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}
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fn visit_str<E>(self, value: &str) -> Result<Self::Value, E>
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where
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E: de::Error,
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{
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Ok(hex::decode(value.trim_start_matches("0x"))
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.map_err(|e| de::Error::custom(format!("invalid hex ({:?})", e)))?)
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}
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}
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#[cfg(test)]
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mod test {
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use super::*;
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#[test]
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fn encoding() {
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let bytes = vec![0, 255];
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let hex = encode(&bytes);
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assert_eq!(hex.as_str(), "0x00ff");
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let bytes = vec![];
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let hex = encode(&bytes);
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assert_eq!(hex.as_str(), "0x");
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let bytes = vec![1, 2, 3];
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let hex = encode(&bytes);
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assert_eq!(hex.as_str(), "0x010203");
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}
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}
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