106 lines
2.6 KiB
Rust
106 lines
2.6 KiB
Rust
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use std::num::{ParseIntError, ParseFloatError};
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use thiserror::Error;
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#[derive(Clone, Debug, Error)]
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pub enum ParseError {
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#[error("{0}")]
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StrEscape(#[from] StrEscapeError),
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#[error("{0}")]
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Integer(#[from] ParseIntError),
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#[error("{0}")]
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Float(#[from] ParseFloatError),
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}
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#[derive(Clone, Copy, Debug, Error)]
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pub enum StrEscapeError {
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#[error("EOF in string escape")]
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Eof,
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#[error("EOF in string escape \\x")]
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HexEof,
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#[error("EOF in string escape \\u")]
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UnicodeEof,
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#[error("Invalid string escape \\{0}")]
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Invalid(char),
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#[error("Invalid hex digit '{0}' in string escape")]
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InvalidHex(char),
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#[error("Missing brace after string escape \\u")]
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MissingBrace,
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#[error("Invalid codepoint in string escape: {0:x}")]
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InvalidCodepoint(u32),
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#[error("Codepoint in string escape too large")]
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CodepointTooLarge,
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}
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pub fn parse_str_escapes(src: &str) -> Result<String, StrEscapeError> {
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let mut s = String::with_capacity(src.len());
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let mut chars = src.chars();
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while let Some(c) = chars.next() {
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if c != '\\' { s.push(c); continue }
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let c = chars.next().ok_or(StrEscapeError::Eof)?;
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match c {
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'"' | '\'' | '\\' => s.push(c),
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'0' => s.push('\0'),
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'a' => s.push('\x07'),
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'b' => s.push('\x08'),
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't' => s.push('\t'),
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'n' => s.push('\n'),
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'v' => s.push('\x0b'),
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'f' => s.push('\x0c'),
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'r' => s.push('\r'),
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'e' => s.push('\x1b'),
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'x' => {
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let c = chars.next().ok_or(StrEscapeError::HexEof)?;
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let n1 = c.to_digit(16).ok_or(StrEscapeError::InvalidHex(c))?;
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let c = chars.next().ok_or(StrEscapeError::HexEof)?;
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let n2 = c.to_digit(16).ok_or(StrEscapeError::InvalidHex(c))?;
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// can't panic: all bytes 0..256 are valid codepoints
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s.push(char::from_u32(n1 * 16 + n2).unwrap());
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},
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'u' => {
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let Some('{') = chars.next() else {
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return Err(StrEscapeError::MissingBrace)
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};
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let mut n = 0u32;
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loop {
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let Some(c) = chars.next() else {
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return Err(StrEscapeError::UnicodeEof)
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};
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if c == '}' { break }
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if n >= 0x1000_0000u32 {
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return Err(StrEscapeError::CodepointTooLarge)
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}
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n = n * 16 + c.to_digit(16).ok_or(StrEscapeError::InvalidHex(c))?;
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}
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let ch = char::from_u32(n).ok_or(StrEscapeError::InvalidCodepoint(n))?;
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s.push(ch);
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},
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c => return Err(StrEscapeError::Invalid(c)),
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}
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}
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Ok(s)
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}
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pub fn parse_float(f: &str) -> Result<f64, ParseFloatError> {
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let mut s = String::new();
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for c in f.chars() {
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if c != '_' {
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s.push(c);
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}
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}
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s.parse()
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}
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pub fn parse_int(f: &str, radix: u32) -> Result<i64, ParseIntError> {
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let mut s = String::new();
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for c in f.chars() {
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if c != '_' {
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s.push(c);
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}
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}
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i64::from_str_radix(&s, radix)
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}
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