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#[cfg(feature = "codegen")]
pub fn generate_trie<'d, W: std::io::Write, V: std::fmt::Display>(
file: &mut W,
prefix: &str,
value_type: &str,
data: impl Iterator<Item = (&'d str, V)>,
limit: usize,
) -> Result<(), std::io::Error> {
codegen::generate_trie(file, prefix, value_type, data, limit)
}
pub struct DictTrie<V: 'static> {
pub root: &'static DictTrieNode<V>,
pub unicode: &'static crate::DictTable<V>,
pub range: core::ops::RangeInclusive<usize>,
}
impl<V> DictTrie<V> {
pub fn find(&self, word: &'_ unicase::UniCase<&str>) -> Option<&'static V> {
if self.range.contains(&word.len()) {
let bytes = word.as_bytes();
let mut child = &self.root;
for i in 0..bytes.len() {
match child.children {
DictTrieChild::Nested(n) => {
let byte = bytes[i];
let index = if (b'a'..b'z').contains(&byte) {
byte - b'a'
} else if (b'A'..b'Z').contains(&byte) {
byte - b'A'
} else {
return self.unicode.find(word);
};
debug_assert!(index < 26);
if let Some(next) = n[index as usize].as_ref() {
child = next;
} else {
return None;
}
}
DictTrieChild::Flat(t) => {
let remaining = &bytes[i..bytes.len()];
let remaining = unsafe { core::str::from_utf8_unchecked(remaining) };
let remaining = if word.is_ascii() {
unicase::UniCase::ascii(remaining)
} else {
unicase::UniCase::unicode(remaining)
};
return t.find(&remaining);
}
}
}
child.value.as_ref()
} else {
None
}
}
}
pub struct DictTrieNode<V: 'static> {
pub children: DictTrieChild<V>,
pub value: Option<V>,
}
pub enum DictTrieChild<V: 'static> {
Nested(&'static [Option<&'static DictTrieNode<V>>; 26]),
Flat(&'static crate::DictTable<V>),
}
#[cfg(feature = "codegen")]
mod codegen {
pub(super) fn generate_trie<'d, W: std::io::Write, V: std::fmt::Display>(
file: &mut W,
prefix: &str,
value_type: &str,
data: impl Iterator<Item = (&'d str, V)>,
limit: usize,
) -> Result<(), std::io::Error> {
let mut root = DynRoot::new(data);
root.burst(limit);
let unicode_table_name = format!("{}_UNICODE_TABLE", prefix);
writeln!(
file,
"pub static {}_TRIE: dictgen::DictTrie<{}> = dictgen::DictTrie {{",
prefix, value_type
)?;
writeln!(file, " root: &{},", gen_node_name(prefix, ""))?;
writeln!(file, " unicode: &{},", &unicode_table_name)?;
writeln!(
file,
" range: {}..={},",
root.range.start(),
root.range.end()
)?;
writeln!(file, "}};")?;
writeln!(file)?;
crate::generate_table(
file,
&unicode_table_name,
value_type,
root.unicode.into_iter(),
)?;
writeln!(file)?;
let mut nodes = vec![("".to_owned(), &root.root)];
while let Some((start, node)) = nodes.pop() {
let node_name = gen_node_name(prefix, &start);
let children_name = gen_children_name(prefix, &start);
writeln!(
file,
"static {}: dictgen::DictTrieNode<{}> = dictgen::DictTrieNode {{",
node_name, value_type
)?;
writeln!(
file,
" children: {}(&{}),",
gen_type_name(&node.children),
children_name
)?;
if let Some(value) = node.value.as_ref() {
writeln!(file, " value: Some({}),", value)?;
} else {
writeln!(file, " value: None,")?;
}
writeln!(file, "}};")?;
writeln!(file)?;
match &node.children {
DynChild::Nested(n) => {
writeln!(
file,
"static {}: [Option<&dictgen::DictTrieNode<{}>>; 26] = [",
children_name, value_type,
)?;
for b in b'a'..=b'z' {
if let Some(child) = n.get(&b) {
let c = b as char;
let next_start = format!("{}{}", start, c);
writeln!(file, " Some(&{}),", gen_node_name(prefix, &next_start))?;
nodes.push((next_start, child));
} else {
writeln!(file, " None,")?;
}
}
writeln!(file, "];")?;
}
DynChild::Flat(v) => {
let table_input = v.iter().map(|(k, v)| {
let k = std::str::from_utf8(k).expect("this was originally a `str`");
(k, v)
});
crate::generate_table(file, &children_name, value_type, table_input)?;
}
}
writeln!(file)?;
writeln!(file)?;
}
Ok(())
}
fn gen_node_name(prefix: &str, start: &str) -> String {
if start.is_empty() {
format!("{}_NODE", prefix)
} else {
let mut start = start.to_owned();
start.make_ascii_uppercase();
format!("{}_{}_NODE", prefix, start)
}
}
fn gen_children_name(prefix: &str, start: &str) -> String {
if start.is_empty() {
format!("{}_CHILDREN", prefix)
} else {
let mut start = start.to_owned();
start.make_ascii_uppercase();
format!("{}_{}_CHILDREN", prefix, start)
}
}
fn gen_type_name<V>(leaf: &DynChild<V>) -> &'static str {
match leaf {
DynChild::Nested(_) => "dictgen::DictTrieChild::Nested",
DynChild::Flat(_) => "dictgen::DictTrieChild::Flat",
}
}
struct DynRoot<'s, V> {
root: DynNode<'s, V>,
unicode: Vec<(&'s str, V)>,
range: std::ops::RangeInclusive<usize>,
}
impl<'s, V> DynRoot<'s, V> {
fn new(data: impl Iterator<Item = (&'s str, V)>) -> Self {
let mut overflow = Vec::new();
let mut unicode = Vec::default();
let mut smallest = usize::MAX;
let mut largest = usize::MIN;
let mut existing = std::collections::HashSet::new();
let mut empty = None;
for (key, value) in data {
if existing.contains(key) {
panic!("Duplicate present: {}", key);
}
existing.insert(key);
if key.is_empty() {
empty = Some(value);
} else {
smallest = std::cmp::min(smallest, key.len());
largest = std::cmp::max(largest, key.len());
if key.bytes().all(|b| b.is_ascii_alphabetic()) {
overflow.push((key.as_bytes(), value));
} else {
unicode.push((key, value));
}
}
}
Self {
root: DynNode {
children: DynChild::Flat(overflow),
value: empty,
},
unicode,
range: smallest..=largest,
}
}
fn burst(&mut self, limit: usize) {
self.root.burst(limit);
}
}
struct DynNode<'s, V> {
children: DynChild<'s, V>,
value: Option<V>,
}
impl<'s, V> DynNode<'s, V> {
fn burst(&mut self, limit: usize) {
self.children.burst(limit)
}
}
enum DynChild<'s, V> {
Nested(std::collections::BTreeMap<u8, DynNode<'s, V>>),
Flat(Vec<(&'s [u8], V)>),
}
impl<'s, V> DynChild<'s, V> {
fn burst(&mut self, limit: usize) {
match self {
DynChild::Nested(children) => {
for child in children.values_mut() {
child.burst(limit);
}
}
DynChild::Flat(v) if v.len() < limit => (),
DynChild::Flat(v) => {
let mut old_v = Vec::new();
std::mem::swap(&mut old_v, v);
let mut nodes = std::collections::BTreeMap::new();
for (key, value) in old_v {
assert!(!key.is_empty());
let start = key[0].to_ascii_lowercase();
assert!(start.is_ascii_alphabetic());
let node = nodes.entry(start).or_insert_with(|| DynNode {
children: DynChild::Flat(Vec::new()),
value: None,
});
let remaining = &key[1..];
if remaining.is_empty() {
assert!(node.value.is_none());
node.value = Some(value);
} else {
match &mut node.children {
DynChild::Nested(_) => {
unreachable!("Only overflow at this point")
}
DynChild::Flat(ref mut v) => {
v.push((remaining, value));
}
}
}
}
*self = DynChild::Nested(nodes);
self.burst(limit);
}
}
}
}
}