76 lines
2.4 KiB
Rust
76 lines
2.4 KiB
Rust
// SPDX-License-Identifier: CC0-1.0
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//! Bitcoin string parsing utilities.
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//!
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//! This module provides utility types and traits
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//! to support handling and parsing strings within `rust-bitcoin`.
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use core::fmt;
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use internals::write_err;
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use crate::prelude::String;
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/// Trait that allows types to be initialized from hex strings
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pub trait FromHexStr: Sized {
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/// An error occurred while parsing the hex string.
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type Error;
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/// Parses provided string as hex requiring 0x prefix.
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///
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/// This is intended for user-supplied inputs or already-existing protocols in which 0x prefix is used.
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fn from_hex_str<S: AsRef<str> + Into<String>>(s: S) -> Result<Self, FromHexError<Self::Error>> {
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if !s.as_ref().starts_with("0x") {
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Err(FromHexError::MissingPrefix(s.into()))
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} else {
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Ok(Self::from_hex_str_no_prefix(s.as_ref().trim_start_matches("0x"))?)
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}
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}
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/// Parses provided string as hex without requiring 0x prefix.
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///
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/// This is **not** recommended for user-supplied inputs because of possible confusion with decimals.
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/// It should be only used for existing protocols which always encode values as hex without 0x prefix.
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fn from_hex_str_no_prefix<S: AsRef<str> + Into<String>>(s: S) -> Result<Self, Self::Error>;
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}
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/// Hex parsing error
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#[derive(Debug, Eq, PartialEq, Clone)]
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pub enum FromHexError<E> {
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/// The input was not a valid hex string, contains the error that occurred while parsing.
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ParseHex(E),
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/// The input is missing `0x` prefix, contains the invalid input.
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MissingPrefix(String),
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}
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impl<E> From<E> for FromHexError<E> {
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fn from(e: E) -> Self { FromHexError::ParseHex(e) }
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}
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impl<E: fmt::Display> fmt::Display for FromHexError<E> {
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fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
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use self::FromHexError::*;
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match *self {
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ParseHex(ref e) => write_err!(f, "failed to parse hex string"; e),
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MissingPrefix(ref value) =>
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write_err!(f, "the input value `{}` is missing the `0x` prefix", value; self),
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}
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}
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}
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#[cfg(feature = "std")]
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impl<E> std::error::Error for FromHexError<E>
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where
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E: std::error::Error + 'static,
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{
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fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
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use self::FromHexError::*;
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match *self {
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ParseHex(ref e) => Some(e),
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MissingPrefix(_) => None,
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}
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}
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}
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