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/*
* SPDX-FileCopyrightText: 2020 Stalwart Labs Ltd <hello@stalw.art>
*
* SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
*/
use std::{
iter::{Enumerate, Peekable},
slice::Iter,
};
use crate::{compiler::Number, runtime::eval::IntoString};
use super::{BinaryOperator, Token, UnaryOperator};
pub(crate) struct Tokenizer<'x, F>
where
F: Fn(&str, bool) -> Result<Token, String>,
{
pub(crate) iter: Peekable<Enumerate<Iter<'x, u8>>>,
token_map: F,
buf: Vec<u8>,
depth: u32,
next_token: Vec<Token>,
has_number: bool,
has_dot: bool,
has_alpha: bool,
is_start: bool,
is_eof: bool,
}
impl<'x, F> Tokenizer<'x, F>
where
F: Fn(&str, bool) -> Result<Token, String>,
{
#[cfg(test)]
pub fn new(expr: &'x str, token_map: F) -> Self {
Self::from_iter(expr.as_bytes().iter().enumerate().peekable(), token_map)
}
#[allow(clippy::should_implement_trait)]
pub(crate) fn from_iter(iter: Peekable<Enumerate<Iter<'x, u8>>>, token_map: F) -> Self {
Self {
iter,
buf: Vec::new(),
depth: 0,
next_token: Vec::with_capacity(2),
has_number: false,
has_dot: false,
has_alpha: false,
is_start: true,
is_eof: false,
token_map,
}
}
#[allow(clippy::should_implement_trait)]
pub(crate) fn next(&mut self) -> Result<Option<Token>, String> {
if let Some(token) = self.next_token.pop() {
return Ok(Some(token));
} else if self.is_eof {
return Ok(None);
}
while let Some((_, &ch)) = self.iter.next() {
match ch {
b'A'..=b'Z' | b'a'..=b'z' | b'_' => {
self.buf.push(ch);
self.has_alpha = true;
}
b'0'..=b'9' => {
self.buf.push(ch);
self.has_number = true;
}
b'.' => {
self.buf.push(ch);
self.has_dot = true;
}
b'}' => {
self.is_eof = true;
break;
}
b'[' if matches!(self.buf.get(0..7), Some(b"header.")) => {
self.buf.push(ch);
}
b'-' if self.buf.last().is_some_and( |c| *c == b'[')
|| matches!(self.buf.get(0..7), Some(b"header.")) =>
{
self.buf.push(ch);
}
b':' if self.buf.contains(&b'.') => {
self.buf.push(ch);
}
b']' if self.buf.contains(&b'[') => {
self.buf.push(b']');
}
b'*' if self.buf.last().is_some_and( |&c| c == b'[' || c == b'.') => {
self.buf.push(ch);
}
_ => {
let prev_token = if !self.buf.is_empty() {
self.is_start = false;
self.parse_buf()?.into()
} else {
None
};
let token = match ch {
b'&' => {
if matches!(self.iter.peek(), Some((_, b'&'))) {
self.iter.next();
}
Token::BinaryOperator(BinaryOperator::And)
}
b'|' => {
if matches!(self.iter.peek(), Some((_, b'|'))) {
self.iter.next();
}
Token::BinaryOperator(BinaryOperator::Or)
}
b'!' => {
if matches!(self.iter.peek(), Some((_, b'='))) {
self.iter.next();
Token::BinaryOperator(BinaryOperator::Ne)
} else {
Token::UnaryOperator(UnaryOperator::Not)
}
}
b'^' => Token::BinaryOperator(BinaryOperator::Xor),
b'(' => {
self.depth += 1;
Token::OpenParen
}
b')' => {
if self.depth == 0 {
return Err("Unmatched close parenthesis".to_string());
}
self.depth -= 1;
Token::CloseParen
}
b'+' => Token::BinaryOperator(BinaryOperator::Add),
b'*' => Token::BinaryOperator(BinaryOperator::Multiply),
b'/' => Token::BinaryOperator(BinaryOperator::Divide),
b'-' => {
if self.is_start {
Token::UnaryOperator(UnaryOperator::Minus)
} else {
Token::BinaryOperator(BinaryOperator::Subtract)
}
}
b'=' => match self.iter.next() {
Some((_, b'=')) => Token::BinaryOperator(BinaryOperator::Eq),
Some((_, b'>')) => Token::BinaryOperator(BinaryOperator::Ge),
Some((_, b'<')) => Token::BinaryOperator(BinaryOperator::Le),
_ => Token::BinaryOperator(BinaryOperator::Eq),
},
b'>' => match self.iter.peek() {
Some((_, b'=')) => {
self.iter.next();
Token::BinaryOperator(BinaryOperator::Ge)
}
_ => Token::BinaryOperator(BinaryOperator::Gt),
},
b'<' => match self.iter.peek() {
Some((_, b'=')) => {
self.iter.next();
Token::BinaryOperator(BinaryOperator::Le)
}
_ => Token::BinaryOperator(BinaryOperator::Lt),
},
b',' => Token::Comma,
b'[' => Token::OpenBracket,
b']' => Token::CloseBracket,
b' ' | b'\r' | b'\n' => {
if prev_token.is_some() {
return Ok(prev_token);
} else {
continue;
}
}
b'\"' | b'\'' => {
let mut buf = Vec::with_capacity(16);
let stop_ch = ch;
let mut last_ch = 0;
let mut found_end = false;
for (_, &ch) in self.iter.by_ref() {
if last_ch != b'\\' {
if ch != stop_ch {
buf.push(ch);
} else {
found_end = true;
break;
}
} else {
match ch {
b'n' => {
buf.push(b'\n');
}
b'r' => {
buf.push(b'\r');
}
b't' => {
buf.push(b'\t');
}
_ => {
buf.push(ch);
}
}
}
last_ch = ch;
}
if found_end {
Token::String(
String::from_utf8(buf)
.map_err(|_| "Invalid UTF-8".to_string())?,
)
} else {
return Err("Unterminated string".to_string());
}
}
_ => {
return Err(format!("Invalid character {:?}", char::from(ch),));
}
};
self.is_start = matches!(
token,
Token::OpenParen | Token::Comma | Token::BinaryOperator(_)
);
return if prev_token.is_some() {
self.next_token.push(token);
Ok(prev_token)
} else {
Ok(Some(token))
};
}
}
}
if self.depth > 0 {
Err("Unmatched open parenthesis".to_string())
} else if !self.buf.is_empty() {
self.parse_buf().map(Some)
} else {
Ok(None)
}
}
fn parse_buf(&mut self) -> Result<Token, String> {
let buf = std::mem::take(&mut self.buf).into_string();
if self.has_number && !self.has_alpha {
self.has_number = false;
if self.has_dot {
self.has_dot = false;
buf.parse::<f64>()
.map(|f| Token::Number(Number::Float(f)))
.map_err(|_| format!("Invalid float value {}", buf,))
} else {
buf.parse::<i64>()
.map(|i| Token::Number(Number::Integer(i)))
.map_err(|_| format!("Invalid integer value {}", buf,))
}
} else {
let has_dot = self.has_dot;
let has_number = self.has_number;
self.has_alpha = false;
self.has_number = false;
self.has_dot = false;
if !has_number && !has_dot && [4, 5].contains(&buf.len()) {
if buf == "true" {
return Ok(Token::Number(Number::Integer(1)));
} else if buf == "false" {
return Ok(Token::Number(Number::Integer(0)));
}
}
(self.token_map)(&buf, has_dot)
}
}
}