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// This file is part of ICU4X. For terms of use, please see the file
// called LICENSE at the top level of the ICU4X source tree
#![cfg_attr(not(any(test, doc)), no_std)]
#![cfg_attr(
not(test),
deny(
clippy::indexing_slicing,
clippy::unwrap_used,
clippy::expect_used,
clippy::panic,
)
)]
#![warn(missing_docs)]
//! Normalizing text into Unicode Normalization Forms.
//!
//! This module is published as its own crate ([`icu_normalizer`](https://docs.rs/icu_normalizer/latest/icu_normalizer/))
//! and as part of the [`icu`](https://docs.rs/icu/latest/icu/) crate. See the latter for more details on the ICU4X project.
//!
//! # Functionality
//!
//! The top level of the crate provides normalization of input into the four normalization forms defined in [UAX #15: Unicode
//! Normalization Forms](https://www.unicode.org/reports/tr15/): NFC, NFD, NFKC, and NFKD.
//!
//! Three kinds of contiguous inputs are supported: known-well-formed UTF-8 (`&str`), potentially-not-well-formed UTF-8,
//! and potentially-not-well-formed UTF-16. Additionally, an iterator over `char` can be wrapped in a normalizing iterator.
//!
//! The `uts46` module provides the combination of mapping and normalization operations for [UTS #46: Unicode IDNA
//! Compatibility Processing](https://www.unicode.org/reports/tr46/). This functionality is not meant to be used by
//! applications directly. Instead, it is meant as a building block for a full implementation of UTS #46, such as the
//! [`idna`](https://docs.rs/idna/latest/idna/) crate.
//!
//! The `properties` module provides the non-recursive canonical decomposition operation on a per `char` basis and
//! the canonical compositon operation given two `char`s. It also provides access to the Canonical Combining Class
//! property. These operations are primarily meant for [HarfBuzz](https://harfbuzz.github.io/), the types
//! [`CanonicalComposition`](properties::CanonicalComposition), [`CanonicalDecomposition`](properties::CanonicalDecomposition),
//! and [`CanonicalCombiningClassMap`](properties::CanonicalCombiningClassMap) implement the [`harfbuzz_traits`] if
//! the `harfbuzz_traits` Cargo feature is enabled.
//!
//! Notably, this normalizer does _not_ provide the normalization “quick check” that can result in “maybe” in
//! addition to “yes” and “no”. The normalization checks provided by this crate always give a definitive
//! non-“maybe” answer.
//!
//! # Examples
//!
//! ```
//! let nfc = icu_normalizer::ComposingNormalizerBorrowed::new_nfc();
//! assert_eq!(nfc.normalize("a\u{0308}"), "ä");
//! assert!(nfc.is_normalized("ä"));
//!
//! let nfd = icu_normalizer::DecomposingNormalizerBorrowed::new_nfd();
//! assert_eq!(nfd.normalize("ä"), "a\u{0308}");
//! assert!(!nfd.is_normalized("ä"));
//! ```
extern crate alloc;
#[cfg(feature = "serde")]
type Trie<'trie> = CodePointTrie<'trie, u32>;
#[cfg(not(feature = "serde"))]
type Trie<'trie> = FastCodePointTrie<'trie, u32>;
type CombiningBuffer = SmallVec<[CharacterAndClass; 2]>;
type CompositionTrie<'trie> = FastCodePointTrie<'trie, u16>;
// We don't depend on icu_properties to minimize deps, but we want to be able
// to ensure we're using the right CCC values
macro_rules! ccc {
($name:ident, $num:expr) => {
const {
#[cfg(feature = "icu_properties")]
if icu_properties::props::CanonicalCombiningClass::$name.to_icu4c_value() != $num {
panic!("icu_normalizer has incorrect ccc values")
}
CanonicalCombiningClass::from_icu4c_value($num)
}
};
}
#[cfg(feature = "harfbuzz_traits")]
mod harfbuzz;
#[cfg(feature = "latin1")]
pub mod latin1;
pub mod properties;
pub mod provider;
pub mod uts46;
#[cfg(feature = "serde")]
use crate::provider::CanonicalCompositions;
use crate::provider::CanonicalCompositionsNew;
use crate::provider::DecompositionData;
use crate::provider::NormalizerNfdDataV1;
use crate::provider::NormalizerNfkdDataV1;
use crate::provider::NormalizerUts46DataV1;
use alloc::borrow::Cow;
use alloc::string::String;
use core::char::REPLACEMENT_CHARACTER;
use core::marker::PhantomData;
#[cfg(feature = "serde")]
use icu_collections::char16trie::Char16Trie;
#[cfg(feature = "serde")]
use icu_collections::char16trie::Char16TrieIterator;
#[cfg(feature = "serde")]
use icu_collections::char16trie::TrieResult;
use icu_collections::codepointtrie::AbstractCodePointTrie;
use icu_collections::codepointtrie::CharIterWithTrie;
use icu_collections::codepointtrie::CharsWithTrieDefaultForAsciiEx;
use icu_collections::codepointtrie::CodePointTrie;
use icu_collections::codepointtrie::FastCodePointTrie;
use icu_collections::codepointtrie::WithTrie;
#[cfg(feature = "icu_properties")]
use icu_properties::props::CanonicalCombiningClass;
use icu_provider::prelude::*;
use provider::DecompositionTables;
#[cfg(feature = "serde")]
use provider::NormalizerNfcV1;
use provider::NormalizerNfcV2;
use provider::NormalizerNfdTablesV1;
use provider::NormalizerNfkdTablesV1;
use smallvec::SmallVec;
#[cfg(feature = "utf16_iter")]
use utf16_iter::Utf16CharsWithTrieEx;
#[cfg(feature = "utf8_iter")]
use utf8_iter::Utf8CharsEx;
#[cfg(feature = "utf8_iter")]
use utf8_iter::Utf8CharsWithTrieDefaultForAsciiEx;
use zerovec::{zeroslice, ZeroSlice};
// The optimizations in the area where `likely` is used
// are extremely brittle. `likely` is useful in the typed-trie
// case on the UTF-16 fast path, but in order not to disturb
// the untyped-trie case on the UTF-16 fast path, make the
// annotations no-ops in the untyped-trie case.
// `cold_path` and `likely` come from
// for permission to relicense under Unicode-3.0.
#[cfg(not(feature = "serde"))]
#[inline(always)]
#[cold]
fn cold_path() {}
#[cfg(not(feature = "serde"))]
#[inline(always)]
pub(crate) fn likely(b: bool) -> bool {
if b {
true
} else {
cold_path();
false
}
}
#[cfg(not(feature = "serde"))]
#[inline(always)]
pub(crate) fn unlikely(b: bool) -> bool {
if b {
cold_path();
true
} else {
false
}
}
/// No-op for typed trie case.
#[cfg(feature = "serde")]
#[inline(always)]
fn likely(b: bool) -> bool {
b
}
/// No-op for typed trie case.
#[cfg(feature = "serde")]
#[inline(always)]
fn unlikely(b: bool) -> bool {
b
}
/// This type exists as a shim for icu_properties CanonicalCombiningClass when the crate is disabled
/// It should not be exposed to users.
#[cfg(not(feature = "icu_properties"))]
#[derive(Copy, Clone, Eq, PartialEq, PartialOrd, Ord)]
struct CanonicalCombiningClass(pub(crate) u8);
#[cfg(not(feature = "icu_properties"))]
impl CanonicalCombiningClass {
const fn from_icu4c_value(v: u8) -> Self {
Self(v)
}
const fn to_icu4c_value(self) -> u8 {
self.0
}
}
const CCC_NOT_REORDERED: CanonicalCombiningClass = ccc!(NotReordered, 0);
const CCC_ABOVE: CanonicalCombiningClass = ccc!(Above, 230);
/// Treatment of the ignorable marker (0xFFFFFFFF) in data.
#[derive(Debug, PartialEq, Eq)]
enum IgnorableBehavior {
/// 0xFFFFFFFF in data is not supported.
Unsupported,
/// Ignorables are ignored.
Ignored,
/// Ignorables are treated as singleton decompositions
/// to the REPLACEMENT CHARACTER.
ReplacementCharacter,
}
pub(crate) trait IteratorPolicy {
const IGNORABLE_BEHAVIOR: IgnorableBehavior;
}
#[derive(Debug)]
struct Uax15Policy;
impl IteratorPolicy for Uax15Policy {
const IGNORABLE_BEHAVIOR: IgnorableBehavior = IgnorableBehavior::Unsupported;
}
/// Marker for UTS 46 ignorables.
///
/// See trie-value-format.md
const IGNORABLE_MARKER: u32 = 0xFFFFFFFF;
/// Marker that the decomposition does not round trip via NFC.
///
/// See trie-value-format.md
const NON_ROUND_TRIP_MARKER: u32 = 1 << 30;
/// Marker that the first character of the decomposition
/// can combine backwards.
///
/// See trie-value-format.md
const BACKWARD_COMBINING_MARKER: u32 = 1 << 31;
/// Mask for the bits have to be zero for this to be a BMP
/// singleton decomposition, or value baked into the surrogate
/// range.
///
/// See trie-value-format.md
const HIGH_ZEROS_MASK: u32 = 0x3FFF0000;
/// Mask for the bits have to be zero for this to be a complex
/// decomposition.
///
/// See trie-value-format.md
const LOW_ZEROS_MASK: u32 = 0xFFE0;
/// Checks if a trie value carries a (non-zero) canonical
/// combining class.
///
/// See trie-value-format.md
fn trie_value_has_ccc(trie_value: u32) -> bool {
(trie_value & 0x3FFFFE00) == 0xD800
}
/// Checks if the trie signifies a special non-starter decomposition.
///
/// See trie-value-format.md
fn trie_value_indicates_special_non_starter_decomposition(trie_value: u32) -> bool {
(trie_value & 0x3FFFFF00) == 0xD900
}
/// Checks if the trie signifies a non-decomposing non-starter.
///
/// See trie-value-format.md
fn trie_value_indicates_non_decomposing_non_starter(trie_value: u32) -> bool {
(trie_value & 0x3FFFFF00) == 0xD800
}
/// Checks if a trie value signifies a character whose decomposition
/// starts with a non-starter.
///
/// See trie-value-format.md
fn decomposition_starts_with_non_starter(trie_value: u32) -> bool {
trie_value_has_ccc(trie_value)
}
/// Extracts a canonical combining class (possibly zero) from a trie value.
///
/// See trie-value-format.md
fn ccc_from_trie_value(trie_value: u32) -> CanonicalCombiningClass {
if trie_value_has_ccc(trie_value) {
CanonicalCombiningClass::from_icu4c_value(trie_value as u8)
} else {
CCC_NOT_REORDERED
}
}
/// The tail (everything after the first character) of the NFKD form U+FDFA
/// as 16-bit units.
static FDFA_NFKD: [u16; 17] = [
0x644, 0x649, 0x20, 0x627, 0x644, 0x644, 0x647, 0x20, 0x639, 0x644, 0x64A, 0x647, 0x20, 0x648,
0x633, 0x644, 0x645,
];
/// Marker value for U+FDFA in NFKD. (Unified with Hangul syllable marker,
/// but they differ by `NON_ROUND_TRIP_MARKER`.)
///
/// See trie-value-format.md
const FDFA_MARKER: u16 = 1;
// These constants originate from page 143 of Unicode 14.0
/// Syllable base
const HANGUL_S_BASE: u32 = 0xAC00;
/// Lead jamo base
const HANGUL_L_BASE: u32 = 0x1100;
/// Vowel jamo base
const HANGUL_V_BASE: u32 = 0x1161;
/// Trail jamo base (deliberately off by one to account for the absence of a trail)
const HANGUL_T_BASE: u32 = 0x11A7;
/// Lead jamo count
const HANGUL_L_COUNT: u32 = 19;
/// Vowel jamo count
const HANGUL_V_COUNT: u32 = 21;
/// Trail jamo count (deliberately off by one to account for the absence of a trail)
const HANGUL_T_COUNT: u32 = 28;
/// Vowel jamo count times trail jamo count
const HANGUL_N_COUNT: u32 = 588;
/// Syllable count
const HANGUL_S_COUNT: u32 = 11172;
/// One past the conjoining jamo block
#[cfg(feature = "serde")]
const HANGUL_JAMO_LIMIT: u32 = 0x1200;
/// Trie value base corresponding for L
const HANGUL_L_TRIE_VAL_BASE: u16 = 0xD6A7;
/// If `opt` is `Some`, unwrap it. If `None`, panic if debug assertions
/// are enabled and return `default` if debug assertions are not enabled.
///
/// Use this only if the only reason why `opt` could be `None` is bogus
/// data from the provider.
#[inline(always)]
fn unwrap_or_gigo<T>(opt: Option<T>, default: T) -> T {
if let Some(val) = opt {
val
} else {
// GIGO case
debug_assert!(false);
default
}
}
/// Convert a `u32` _obtained from data provider data_ to `char`.
#[inline(always)]
fn char_from_u32(u: u32) -> char {
unwrap_or_gigo(core::char::from_u32(u), REPLACEMENT_CHARACTER)
}
/// Convert a `u16` _obtained from data provider data_ to `char`.
#[inline(always)]
fn char_from_u16(u: u16) -> char {
char_from_u32(u32::from(u))
}
const EMPTY_U16: &ZeroSlice<u16> = zeroslice![];
const EMPTY_CHAR: &ZeroSlice<char> = zeroslice![];
#[inline(always)]
fn in_inclusive_range(c: char, start: char, end: char) -> bool {
u32::from(c).wrapping_sub(u32::from(start)) <= (u32::from(end) - u32::from(start))
}
#[inline(always)]
#[cfg(feature = "utf16_iter")]
fn in_inclusive_range16(u: u16, start: u16, end: u16) -> bool {
u.wrapping_sub(start) <= (end - start)
}
#[derive(Debug)]
pub(crate) enum CanonicalCompositionsPayload {
Current(DataPayload<NormalizerNfcV2>),
#[cfg(feature = "serde")]
Legacy(DataPayload<NormalizerNfcV1>),
}
impl<'data> CanonicalCompositionsPayload {
pub(crate) fn as_borrowed(&'data self) -> CanonicalCompositionsBorrowed<'data> {
match self {
CanonicalCompositionsPayload::Current(data_payload) => {
CanonicalCompositionsBorrowed::Current(data_payload.get())
}
#[cfg(feature = "serde")]
CanonicalCompositionsPayload::Legacy(data_payload) => {
CanonicalCompositionsBorrowed::Legacy(data_payload.get())
}
}
}
}
#[derive(Debug, Copy, Clone)]
pub(crate) enum CanonicalCompositionsBorrowed<'data> {
Current(&'data CanonicalCompositionsNew<'data>),
#[cfg(feature = "serde")]
Legacy(&'data CanonicalCompositions<'data>),
}
impl CanonicalCompositionsBorrowed<'static> {
pub(crate) const fn static_to_owned(self) -> CanonicalCompositionsPayload {
match self {
CanonicalCompositionsBorrowed::Current(s) => {
CanonicalCompositionsPayload::Current(DataPayload::from_static_ref(s))
}
#[cfg(feature = "serde")]
CanonicalCompositionsBorrowed::Legacy(s) => {
CanonicalCompositionsPayload::Legacy(DataPayload::from_static_ref(s))
}
}
}
}
impl<'data> CanonicalCompositionsBorrowed<'data> {
pub(crate) fn as_ref(&'data self) -> CanonicalCompositionsRef<'data> {
match self {
CanonicalCompositionsBorrowed::Current(s) => CanonicalCompositionsRef::Current(
<&CompositionTrie<'data>>::try_from(&s.trie)
.unwrap_or_else(|_| unreachable!("Incompatible data")),
&s.linear16,
&s.linear24,
),
#[cfg(feature = "serde")]
CanonicalCompositionsBorrowed::Legacy(s) => {
CanonicalCompositionsRef::Legacy(s.canonical_compositions.clone())
}
}
}
}
#[derive(Debug)]
pub(crate) enum CanonicalCompositionsRef<'data> {
Current(
&'data CompositionTrie<'data>,
&'data ZeroSlice<(u16, u16)>,
&'data ZeroSlice<(char, char)>,
),
#[cfg(feature = "serde")]
Legacy(Char16Trie<'data>),
}
impl<'data> CanonicalCompositionsRef<'data> {
/// Performs canonical composition (including Hangul) on a pair of
/// characters or returns `None` if these characters don't compose.
/// Composition exclusions are taken into account.
///
/// TODO: Have the caller retain more state and have this function return
/// more information that is useful for retaining information between
/// attempts to compose in a sequence of such attempts:
///
/// * We can return the linear search slice when we search through it but don't find anything.
/// * We can know that no further matches are possible.
/// * We can know that the starter was a special ASCII vowel.
/// * We can know that we just formed a Hangul LV syllable.
pub(crate) fn compose(&self, starter: char, second: char) -> Option<char> {
match self {
CanonicalCompositionsRef::Current(trie, linear16, linear24) => {
// According to Compiler Explorer, the `match` optimizes to a bitfield lookup.
// Don't bother optimizing manually without inspecting the generated assembly.
let (primary, secondary) = match starter {
'a' | 'e' | 'i' | 'o' | 'u' | 'A' | 'E' | 'I' | 'O' | 'U' => {
// This special case balances out the max length of entries
// in `linear` so that no entry exceeds 10 items as of Unicode 17.
(second, starter)
}
_ => (starter, second),
};
let packed = trie.scalar(primary);
let len = usize::from(packed & 0b1111);
let index = usize::from(packed >> 4);
if let Some(slice16) = linear16.get_subslice(index..index + len) {
let secondary32 = u32::from(secondary);
for (candidate, composed) in slice16.iter() {
if u32::from(candidate) == secondary32 {
return Some(char_from_u16(composed));
}
}
return None;
}
if packed < 0b1000_0000_0000_0000 {
debug_assert_eq!(packed, 0b0111_1111_1111_1111);
return None;
}
// Mask off the bit that was the most-significant bit in `u16` before we
// shifted right by 4.
let index = index & 0b1_11111_11111; // 11 bits set
if let Some(slice24) = linear24.get_subslice(index..index + len) {
for (candidate, composed) in slice24.iter() {
if candidate == secondary {
return Some(composed);
}
}
return None;
}
// Handle Hangul L after non-BMP, because HarfBuzz isn't actually supposed
// to exercise this case and in the normalizer itself, we come here only
// in NFKC in the case of enclosed Hangul.
if packed >= HANGUL_L_TRIE_VAL_BASE {
// If the debug asserts fail, we have a GIGO case.
debug_assert!(u32::from(primary).wrapping_sub(HANGUL_L_BASE) < HANGUL_L_COUNT);
debug_assert_eq!(
u32::from(packed - HANGUL_L_TRIE_VAL_BASE),
u32::from(primary).wrapping_sub(HANGUL_L_BASE) * HANGUL_N_COUNT
);
let v = u32::from(second).wrapping_sub(HANGUL_V_BASE);
if v < HANGUL_V_COUNT {
// Acconding to Compiler Explorer, multiplication by `HANGUL_T_COUNT`
// optimizes to not actually using a multiplication instruction.
let lv = u32::from(packed - HANGUL_L_TRIE_VAL_BASE) + v * HANGUL_T_COUNT;
// SAFETY: Safe, because the inputs are known to be in range. Notably
// packed cannot have been above 0xFFFF, since it came from `u16`.
// That is, this must be in scalar value range. However, the result
// can still be GIGO if the trie value does not contain the right value
// within its possible range, in which case either of the above debug
// assertions should fail.
return Some(unsafe { char::from_u32_unchecked(HANGUL_S_BASE + lv) });
}
return None;
}
// `starter` is Hangul LV unless GIGO. If the debug asserts fail, we have a GIGO case.
debug_assert!(u32::from(primary).wrapping_sub(HANGUL_S_BASE) < HANGUL_S_COUNT);
debug_assert_eq!(
u32::from(primary).wrapping_sub(HANGUL_S_BASE) % HANGUL_T_COUNT,
0
);
if in_inclusive_range(secondary, '\u{11A8}', '\u{11C2}') {
let lvt = u32::from(primary) + (u32::from(secondary) - HANGUL_T_BASE);
if lvt < 0xD800 {
// SAFETY: Immediately above we checked that `c32` is below the surrogate
// range. (Not using `char::from_u32` itself as a micro optimization.)
// This is only a check about the safe `char` range. The result could
// still be GIGO, wich which case either of the above debug assertions
// should fail.
return Some(unsafe { char::from_u32_unchecked(lvt) });
} else {
// GIGO
// Asserting `false`, although either of the above two debug assertions
// should already have caught this case.
debug_assert!(false);
}
}
None
}
#[cfg(feature = "serde")]
CanonicalCompositionsRef::Legacy(char16_trie) => {
Self::compose_legacy(char16_trie.iter(), starter, second)
}
}
}
/// Performs canonical composition (including Hangul) on a pair of
/// characters on the assumption that the second one is a starter
/// or returns `None` if these characters don't compose.
/// Composition exclusions are taken into account.
///
/// The returned boolean can be true only if `char` a Hangul LV syllable.
///
/// The argument `starter_is_lv` must be set either to false or to the value
/// that this method previously returned alongside `starter`.
pub(crate) fn compose_starter(
&self,
starter: char,
second: char,
starter_is_lv: bool,
) -> Option<(char, bool)> {
if starter_is_lv {
debug_assert!(u32::from(starter).wrapping_sub(HANGUL_S_BASE) < HANGUL_S_COUNT);
debug_assert_eq!(
u32::from(starter).wrapping_sub(HANGUL_S_BASE) % HANGUL_T_COUNT,
0
);
if in_inclusive_range(second, '\u{11A8}', '\u{11C2}') {
// We take the perf hit of checking the returned character for range
// even though we could omit the check if we trusted 100% that the
// other code has no mistakes regarding the stated required semantics
// of `starter_is_lv`.
return Some((
char_from_u32(u32::from(starter) + (u32::from(second) - HANGUL_T_BASE)),
false,
));
}
return None;
}
match self {
CanonicalCompositionsRef::Current(trie, linear16, linear24) => {
// We assume that future versions of Unicode won't introduce starters
// that would compose with ASCII vowels.
let primary = starter;
let secondary = second;
let packed = trie.scalar(primary);
if packed >= HANGUL_L_TRIE_VAL_BASE {
// If the debug asserts fail, we have a GIGO case.
debug_assert!(u32::from(primary).wrapping_sub(HANGUL_L_BASE) < HANGUL_L_COUNT);
debug_assert_eq!(
u32::from(packed - HANGUL_L_TRIE_VAL_BASE),
u32::from(primary).wrapping_sub(HANGUL_L_BASE) * HANGUL_N_COUNT
);
let v = u32::from(second).wrapping_sub(HANGUL_V_BASE);
if v < HANGUL_V_COUNT {
// Acconding to Compiler Explorer, multiplication by `HANGUL_T_COUNT`
// optimizes to not actually using a multiplication instruction.
let lv = u32::from(packed - HANGUL_L_TRIE_VAL_BASE) + v * HANGUL_T_COUNT;
// SAFETY: Safe, because the inputs are known to be in range. Notably
// packed cannot have been above 0xFFFF, since it came from `u16`.
// That is, this must be in scalar value range. However, the result
// can still be GIGO if the trie value does not contain the right value
// within its possible range, in which case either of the above debug
// assertions should fail.
return Some((
unsafe { char::from_u32_unchecked(HANGUL_S_BASE + lv) },
true,
));
}
return None;
}
// Putting the Hangul case above, because in NFD Hangul the above case
// happens with each syllable whereas with the languages for which the
// case immediately below is relevant, the case occurs only once in a
// while.
let len = usize::from(packed & 0b1111);
let index = usize::from(packed >> 4);
if let Some(slice16) = linear16.get_subslice(index..index + len) {
let secondary32 = u32::from(secondary);
for (candidate, composed) in slice16.iter() {
if u32::from(candidate) == secondary32 {
return Some((char_from_u16(composed), false));
}
}
return None;
}
if packed < 0b1000_0000_0000_0000 {
debug_assert_eq!(packed, 0b0111_1111_1111_1111);
return None;
}
// Mask off the bit that was the most-significant bit in `u16` before we
// shifted right by 4.
let index = index & 0b1_11111_11111; // 11 bits set
if let Some(slice24) = linear24.get_subslice(index..index + len) {
for (candidate, composed) in slice24.iter() {
if candidate == secondary {
return Some((composed, false));
}
}
return None;
}
// `starter` is Hangul LV unless GIGO. If the debug asserts fail, we have a GIGO case.
debug_assert!(u32::from(primary).wrapping_sub(HANGUL_S_BASE) < HANGUL_S_COUNT);
debug_assert_eq!(
u32::from(primary).wrapping_sub(HANGUL_S_BASE) % HANGUL_T_COUNT,
0
);
if in_inclusive_range(secondary, '\u{11A8}', '\u{11C2}') {
let lvt = u32::from(primary) + (u32::from(secondary) - HANGUL_T_BASE);
if lvt < 0xD800 {
// SAFETY: Immediately above we checked that `c32` is below the surrogate
// range. (Not using `char::from_u32` itself as a micro optimization.)
// This is only a check about the safe `char` range. The result could
// still be GIGO, wich which case either of the above debug assertions
// should fail.
return Some((unsafe { char::from_u32_unchecked(lvt) }, false));
} else {
// GIGO
// Asserting `false`, although either of the above two debug assertions
// should already have caught this case.
debug_assert!(false);
}
}
None
}
#[cfg(feature = "serde")]
CanonicalCompositionsRef::Legacy(char16_trie) => {
Self::compose_legacy(char16_trie.iter(), starter, second).map(|c| (c, false))
}
}
}
#[cfg(feature = "serde")]
#[cold]
#[inline(never)]
fn compose_legacy(mut iter: Char16TrieIterator, starter: char, second: char) -> Option<char> {
let v = u32::from(second).wrapping_sub(HANGUL_V_BASE);
if v >= HANGUL_JAMO_LIMIT - HANGUL_V_BASE {
// To make the trie smaller, the pairs are stored second character first.
// Given how this method is used in ways where it's known that `second`
// is or isn't a starter. We could potentially split the trie into two
// tries depending on whether `second` is a starter.
match iter.next(second) {
TrieResult::NoMatch => None,
TrieResult::NoValue => match iter.next(starter) {
TrieResult::NoMatch => None,
TrieResult::FinalValue(i) => {
if let Some(c) = char::from_u32(i as u32) {
Some(c)
} else {
// GIGO case
debug_assert!(false);
None
}
}
TrieResult::NoValue | TrieResult::Intermediate(_) => {
// GIGO case
debug_assert!(false);
None
}
},
TrieResult::FinalValue(_) | TrieResult::Intermediate(_) => {
// GIGO case
debug_assert!(false);
None
}
}
} else {
if v < HANGUL_V_COUNT {
let l = u32::from(starter).wrapping_sub(HANGUL_L_BASE);
if l < HANGUL_L_COUNT {
let lv = l * HANGUL_N_COUNT + v * HANGUL_T_COUNT;
// Safe, because the inputs are known to be in range.
return Some(unsafe { char::from_u32_unchecked(HANGUL_S_BASE + lv) });
}
return None;
}
if in_inclusive_range(second, '\u{11A8}', '\u{11C2}') {
let lv = u32::from(starter).wrapping_sub(HANGUL_S_BASE);
if lv < HANGUL_S_COUNT && lv % HANGUL_T_COUNT == 0 {
let lvt = lv + (u32::from(second) - HANGUL_T_BASE);
// Safe, because the inputs are known to be in range.
return Some(unsafe { char::from_u32_unchecked(HANGUL_S_BASE + lvt) });
}
}
None
}
}
}
/// See trie-value-format.md
#[inline(always)]
fn starter_and_decomposes_to_self_impl(trie_val: u32) -> bool {
// The REPLACEMENT CHARACTER has `NON_ROUND_TRIP_MARKER` set,
// and this function needs to ignore that.
(trie_val & !(BACKWARD_COMBINING_MARKER | NON_ROUND_TRIP_MARKER)) == 0
}
/// See trie-value-format.md
#[inline(always)]
#[cfg(feature = "utf8_iter")]
pub fn starter_and_decomposes_to_self_except_replacement(trie_val: u32) -> bool {
// This intentionally leaves `NON_ROUND_TRIP_MARKER` in the value
// to be compared with zero. U+FFFD has that flag set despite really
// being being round-tripping in order to make UTF-8 errors
// ineligible for passthrough.
(trie_val & !BACKWARD_COMBINING_MARKER) == 0
}
/// See trie-value-format.md
#[inline(always)]
fn potential_passthrough_and_cannot_combine_backwards(trie_val: u32) -> bool {
(trie_val & (NON_ROUND_TRIP_MARKER | BACKWARD_COMBINING_MARKER)) == 0
}
/// Struct for holding together a character and the value
/// looked up for it from the NFD trie in a more explicit
/// way than an anonymous pair.
/// Also holds a flag about the supplementary-trie provenance.
#[derive(Debug, PartialEq, Eq)]
struct CharacterAndTrieValue {
character: char,
/// See trie-value-format.md
trie_val: u32,
}
impl CharacterAndTrieValue {
#[inline(always)]
pub fn new(c: char, trie_value: u32) -> Self {
CharacterAndTrieValue {
character: c,
trie_val: trie_value,
}
}
#[inline(always)]
pub fn starter_and_decomposes_to_self(&self) -> bool {
starter_and_decomposes_to_self_impl(self.trie_val)
}
/// See trie-value-format.md
#[inline(always)]
pub fn can_combine_backwards(&self) -> bool {
(self.trie_val & BACKWARD_COMBINING_MARKER) != 0
}
/// See trie-value-format.md
#[inline(always)]
pub fn potential_passthrough(&self) -> bool {
(self.trie_val & NON_ROUND_TRIP_MARKER) == 0
}
}
/// Pack a `char` and a `CanonicalCombiningClass` in
/// 32 bits (the former in the lower 24 bits and the
/// latter in the high 8 bits). The latter can be
/// initialized to 0xFF upon creation, in which case
/// it can be actually set later by calling
/// `set_ccc_from_trie_if_not_already_set`. This is
/// a micro optimization to avoid the Canonical
/// Combining Class trie lookup when there is only
/// one combining character in a sequence. This type
/// is intentionally non-`Copy` to get compiler help
/// in making sure that the class is set on the
/// instance on which it is intended to be set
/// and not on a temporary copy.
///
/// Note that 0xFF is won't be assigned to an actual
/// canonical combining class per definition D104
/// in The Unicode Standard.
//
// NOTE: The Pernosco debugger has special knowledge
// of this struct. Please do not change the bit layout
// or the crate-module-qualified name of this struct
// without coordination.
#[derive(Debug)]
struct CharacterAndClass(u32);
impl<'data> CharacterAndClass {
pub fn new(c: char, ccc: CanonicalCombiningClass) -> Self {
CharacterAndClass(u32::from(c) | (u32::from(ccc.to_icu4c_value()) << 24))
}
pub fn new_with_placeholder(c: char) -> Self {
CharacterAndClass(u32::from(c) | ((0xFF) << 24))
}
pub fn new_with_trie_value(c_tv: CharacterAndTrieValue) -> Self {
Self::new(c_tv.character, ccc_from_trie_value(c_tv.trie_val))
}
pub fn new_starter(c: char) -> Self {
CharacterAndClass(u32::from(c))
}
/// This method must exist for Pernosco to apply its special rendering.
/// Also, this must not be dead code!
pub fn character(&self) -> char {
// SAFETY: Safe, because the low 24 bits came from a `char`
// originally.
unsafe { char::from_u32_unchecked(self.0 & 0xFFFFFF) }
}
/// This method must exist for Pernosco to apply its special rendering.
pub fn ccc(&self) -> CanonicalCombiningClass {
CanonicalCombiningClass::from_icu4c_value((self.0 >> 24) as u8)
}
pub fn character_and_ccc(&self) -> (char, CanonicalCombiningClass) {
(self.character(), self.ccc())
}
pub fn set_ccc_from_trie_if_not_already_set<T: AbstractCodePointTrie<'data, u32>>(
&mut self,
trie: &'data T,
) {
if self.0 >> 24 != 0xFF {
return;
}
let scalar = self.0 & 0xFFFFFF;
// SAFETY: Safe, because the low 24 bits came from a `char`
// originally.
self.0 = ((ccc_from_trie_value(trie.scalar(unsafe { char::from_u32_unchecked(scalar) }))
.to_icu4c_value() as u32)
<< 24)
| scalar;
}
}
/// An iterator adaptor that turns an `Iterator` over `char` into
/// a lazily-decomposed `char` sequence.
#[derive(Debug)]
pub struct Decomposition<'data, I>
where
I: Iterator<Item = char>,
{
inner: DecompositionInner<
'data,
CharIterWithTrie<'data, Trie<'data>, u32, I>,
Trie<'data>,
Uax15Policy,
>,
}
impl<'data, I> Decomposition<'data, I>
where
I: Iterator<Item = char>,
{
/// Constructs a decomposing iterator adapter from a delegate
/// iterator and references to the necessary data, without
/// supplementary data.
///
/// Use `DecomposingNormalizer::normalize_iter()` instead unless
/// there's a good reason to use this constructor directly.
///
/// Public but hidden in order to be able to use this from the
/// collator.
#[doc(hidden)] // used in older versions of collator
#[deprecated = "Use `new_decomposition()` instead"]
pub fn new(
delegate: I,
decompositions: &'data DecompositionData,
tables: &'data DecompositionTables,
) -> Self {
let mut ret = Self {
inner: DecompositionInner::new_with_supplements(
CharIterWithTrie::new(
delegate,
#[allow(clippy::useless_conversion)]
<&Trie<'data>>::try_from(&decompositions.trie)
.unwrap_or_else(|_| unreachable!("Incompatible data")),
),
tables,
None,
),
};
let _ = ret.next();
ret
}
}
impl<I> Iterator for Decomposition<'_, I>
where
I: Iterator<Item = char>,
{
type Item = char;
#[inline]
fn next(&mut self) -> Option<char> {
self.inner.next()
}
}
/// The iterator first yields an extra U+FFFD and then
/// the sequence actually corresponding to the input.
#[doc(hidden)] // used in collator
#[inline(always)]
pub fn new_decomposition<'data, I, T>(
delegate: I,
tables: &'data DecompositionTables,
) -> impl Iterator<Item = char> + 'data
where
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32> + 'data,
T: AbstractCodePointTrie<'data, u32> + 'data,
{
DecompositionInner::<'data, I, T, Uax15Policy>::new_with_supplements(delegate, tables, None)
}
#[derive(Debug)]
struct DecompositionInner<'data, I, T, P>
where
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32>,
T: AbstractCodePointTrie<'data, u32>,
P: IteratorPolicy,
{
// See trie-value-format.md for the trie wrapped in `delegate`
delegate: I,
buffer: CombiningBuffer,
/// The index of the next item to be read from `buffer`.
/// The purpose if this index is to avoid having to move
/// the rest upon every read.
buffer_pos: usize,
// At the start of `next()` if not `None`, this is a pending unnormalized
// starter. When `Decomposition` appears alone, this is never a non-starter.
// However, when `Decomposition` appears inside a `Composition`, this
// may become a non-starter before `decomposing_next()` is called.
pending: Option<CharacterAndTrieValue>, // None at end of stream
scalars16: &'data ZeroSlice<u16>,
scalars24: &'data ZeroSlice<char>,
supplementary_scalars16: &'data ZeroSlice<u16>,
supplementary_scalars24: &'data ZeroSlice<char>,
_phantom_p: PhantomData<P>,
_phantom_t: PhantomData<T>,
}
impl<'data, I, T, P> DecompositionInner<'data, I, T, P>
where
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32>,
T: AbstractCodePointTrie<'data, u32> + 'data,
P: IteratorPolicy,
{
/// Constructs a decomposing iterator adapter from a delegate
/// iterator and references to the necessary data, including
/// supplementary data.
///
/// The iterator first yields a U+0000 and only then the sequence
/// corresponding to the input. Unfortunately, due to the way
/// stack placement of structs work in Rust, the caller is responsible
/// for dealing with the initial U+0000. Alternatively, callers in this
/// crate file can (and should) call `init()`.
#[inline(always)]
fn new_with_supplements(
delegate: I,
tables: &'data DecompositionTables,
supplementary_tables: Option<&'data DecompositionTables>,
) -> Self {
DecompositionInner::<I, T, P> {
delegate,
buffer: SmallVec::new(), // Normalized
buffer_pos: 0,
// Initialize with a placeholder starter in case
// the real stream starts with a non-starter.
pending: Some(CharacterAndTrieValue::new('\u{0}', 0)),
scalars16: &tables.scalars16,
scalars24: &tables.scalars24,
supplementary_scalars16: if let Some(supplementary) = supplementary_tables {
&supplementary.scalars16
} else {
EMPTY_U16
},
supplementary_scalars24: if let Some(supplementary) = supplementary_tables {
&supplementary.scalars24
} else {
EMPTY_CHAR
},
_phantom_p: PhantomData,
_phantom_t: PhantomData,
}
}
/// Simplified alternative to calling `next()` and discarding the value after constructing this struct.
fn init(&mut self) {
self.pending = None;
self.gather_and_sort_combining(0);
}
fn push_decomposition16(
&mut self,
offset: usize,
len: usize,
only_non_starters_in_trail: bool,
slice16: &ZeroSlice<u16>,
) -> (char, usize) {
let (starter, tail) = slice16
.get_subslice(offset..offset + len)
.and_then(|slice| slice.split_first())
.map_or_else(
|| {
// GIGO case
debug_assert!(false);
(REPLACEMENT_CHARACTER, EMPTY_U16)
},
|(first, trail)| (char_from_u16(first), trail),
);
if only_non_starters_in_trail {
// All the rest are combining
self.buffer.extend(
tail.iter()
.map(|u| CharacterAndClass::new_with_placeholder(char_from_u16(u))),
);
(starter, 0)
} else {
let mut i = 0;
let mut combining_start = 0;
for u in tail.iter() {
let ch = char_from_u16(u);
let trie_value = self.delegate.trie().scalar(ch);
self.buffer.push(CharacterAndClass::new_with_trie_value(
CharacterAndTrieValue::new(ch, trie_value),
));
i += 1;
// Half-width kana and iota subscript don't occur in the tails
// of these multicharacter decompositions.
if !decomposition_starts_with_non_starter(trie_value) {
combining_start = i;
}
}
(starter, combining_start)
}
}
fn push_decomposition32(
&mut self,
offset: usize,
len: usize,
only_non_starters_in_trail: bool,
slice32: &ZeroSlice<char>,
) -> (char, usize) {
let (starter, tail) = slice32
.get_subslice(offset..offset + len)
.and_then(|slice| slice.split_first())
.unwrap_or_else(|| {
// GIGO case
debug_assert!(false);
(REPLACEMENT_CHARACTER, EMPTY_CHAR)
});
if only_non_starters_in_trail {
// All the rest are combining
self.buffer
.extend(tail.iter().map(CharacterAndClass::new_with_placeholder));
(starter, 0)
} else {
let mut i = 0;
let mut combining_start = 0;
for ch in tail.iter() {
let trie_value = self.delegate.trie().scalar(ch);
self.buffer.push(CharacterAndClass::new_with_trie_value(
CharacterAndTrieValue::new(ch, trie_value),
));
i += 1;
// Half-width kana and iota subscript don't occur in the tails
// of these multicharacter decompositions.
if !decomposition_starts_with_non_starter(trie_value) {
combining_start = i;
}
}
(starter, combining_start)
}
}
fn delegate_next_no_pending(&mut self) -> Option<CharacterAndTrieValue> {
debug_assert!(self.pending.is_none());
loop {
let (c, trie_val) = self.delegate.next()?;
if trie_val == IGNORABLE_MARKER {
match P::IGNORABLE_BEHAVIOR {
IgnorableBehavior::Unsupported => {
debug_assert!(false);
}
IgnorableBehavior::ReplacementCharacter => {
return Some(CharacterAndTrieValue::new(
c,
u32::from(REPLACEMENT_CHARACTER) | NON_ROUND_TRIP_MARKER,
));
}
IgnorableBehavior::Ignored => {
// Else ignore this character by reading the next one from the delegate.
continue;
}
}
}
return Some(CharacterAndTrieValue::new(c, trie_val));
}
}
fn delegate_next(&mut self) -> Option<CharacterAndTrieValue> {
if let Some(pending) = self.pending.take() {
// Only happens as part of `Composition` and as part of
// the contiguous-buffer methods of `DecomposingNormalizer`.
// I.e. does not happen as part of standalone iterator
// usage of `Decomposition`.
Some(pending)
} else {
self.delegate_next_no_pending()
}
}
fn decomposing_next(&mut self, c_and_trie_val: CharacterAndTrieValue) -> char {
let (starter, combining_start) = {
let c = c_and_trie_val.character;
// See trie-value-format.md
let decomposition = c_and_trie_val.trie_val;
// The REPLACEMENT CHARACTER has `NON_ROUND_TRIP_MARKER` set,
// and that flag needs to be ignored here.
if (decomposition & !(BACKWARD_COMBINING_MARKER | NON_ROUND_TRIP_MARKER)) == 0 {
// The character is its own decomposition
(c, 0)
} else {
let high_zeros = (decomposition & HIGH_ZEROS_MASK) == 0;
let low_zeros = (decomposition & LOW_ZEROS_MASK) == 0;
if !high_zeros && !low_zeros {
// Decomposition into two BMP characters: starter and non-starter
let starter = char_from_u32(decomposition & 0x7FFF);
let combining = char_from_u32((decomposition >> 15) & 0x7FFF);
self.buffer
.push(CharacterAndClass::new_with_placeholder(combining));
(starter, 0)
} else if high_zeros {
// Do the check by looking at `c` instead of looking at a marker
// in `singleton` below, because if we looked at the trie value,
// we'd still have to check that `c` is in the Hangul syllable
// range in order for the subsequent interpretations as `char`
// to be safe.
// Alternatively, `FDFA_MARKER` and the Hangul marker could
// be unified. That would add a branch for Hangul and remove
// a branch from singleton decompositions. It seems more
// important to favor Hangul syllables than singleton
// decompositions.
// Note that it would be valid to hoist this Hangul check
// one or even two steps earlier in this check hierarchy.
// Right now, it's assumed the kind of decompositions into
// BMP starter and non-starter, which occur in many languages,
// should be checked before Hangul syllables, which are about
// one language specifically. Hopefully, we get some
// instruction-level parallelism out of the disjointness of
// operations on `c` and `decomposition`.
let hangul_offset = u32::from(c).wrapping_sub(HANGUL_S_BASE); // SIndex in the spec
if hangul_offset < HANGUL_S_COUNT {
debug_assert_eq!(decomposition, 1);
// Hangul syllable
// The math here comes from page 144 of Unicode 14.0
let l = hangul_offset / HANGUL_N_COUNT;
let v = (hangul_offset % HANGUL_N_COUNT) / HANGUL_T_COUNT;
let t = hangul_offset % HANGUL_T_COUNT;
// The unsafe blocks here are OK, because the values stay
// within the Hangul jamo block and, therefore, the scalar
// value range by construction.
self.buffer.push(CharacterAndClass::new_starter(unsafe {
core::char::from_u32_unchecked(HANGUL_V_BASE + v)
}));
let first = unsafe { core::char::from_u32_unchecked(HANGUL_L_BASE + l) };
if t != 0 {
self.buffer.push(CharacterAndClass::new_starter(unsafe {
core::char::from_u32_unchecked(HANGUL_T_BASE + t)
}));
(first, 2)
} else {
(first, 1)
}
} else {
let singleton = decomposition as u16;
if singleton != FDFA_MARKER {
// Decomposition into one BMP character
let starter = char_from_u16(singleton);
(starter, 0)
} else {
// Special case for the NFKD form of U+FDFA.
self.buffer.extend(FDFA_NFKD.map(|u| {
// SAFETY: `FDFA_NFKD` is known not to contain
// surrogates.
CharacterAndClass::new_starter(unsafe {
core::char::from_u32_unchecked(u32::from(u))
})
}));
('\u{0635}', 17)
}
}
} else {
debug_assert!(low_zeros);
// Only 12 of 14 bits used as of Unicode 16.
let offset = (((decomposition & !(0b11 << 30)) >> 16) as usize) - 1;
// Only 3 of 4 bits used as of Unicode 16.
let len_bits = decomposition & 0b1111;
let only_non_starters_in_trail = (decomposition & 0b10000) != 0;
if offset < self.scalars16.len() {
self.push_decomposition16(
offset,
(len_bits + 2) as usize,
only_non_starters_in_trail,
self.scalars16,
)
} else if offset < self.scalars16.len() + self.scalars24.len() {
self.push_decomposition32(
offset - self.scalars16.len(),
(len_bits + 1) as usize,
only_non_starters_in_trail,
self.scalars24,
)
} else if offset
< self.scalars16.len()
+ self.scalars24.len()
+ self.supplementary_scalars16.len()
{
self.push_decomposition16(
offset - (self.scalars16.len() + self.scalars24.len()),
(len_bits + 2) as usize,
only_non_starters_in_trail,
self.supplementary_scalars16,
)
} else {
self.push_decomposition32(
offset
- (self.scalars16.len()
+ self.scalars24.len()
+ self.supplementary_scalars16.len()),
(len_bits + 1) as usize,
only_non_starters_in_trail,
self.supplementary_scalars24,
)
}
}
}
};
// Either we're inside `Composition` or `self.pending.is_none()`.
self.gather_and_sort_combining(combining_start);
starter
}
// This function exists as a borrow check helper.
#[inline(always)]
fn sort_slice_by_ccc(slice: &mut [CharacterAndClass], trie: &'data T) {
// We don't look up the canonical combining class for starters
// of for single combining characters between starters. When
// there's more than one combining character between starters,
// we look up the canonical combining class for each character
// exactly once.
if slice.len() < 2 {
return;
}
slice
.iter_mut()
.for_each(|cc| cc.set_ccc_from_trie_if_not_already_set(trie));
slice.sort_by_key(|cc| cc.ccc());
}
#[cold]
#[inline(never)]
fn push_special_decomposition(buffer: &mut CombiningBuffer, c: char) {
// The Tibetan special cases are starters that decompose into non-starters.
let mapped = match c {
'\u{0340}' => {
// COMBINING GRAVE TONE MARK
CharacterAndClass::new('\u{0300}', CCC_ABOVE)
}
'\u{0341}' => {
// COMBINING ACUTE TONE MARK
CharacterAndClass::new('\u{0301}', CCC_ABOVE)
}
'\u{0343}' => {
// COMBINING GREEK KORONIS
CharacterAndClass::new('\u{0313}', CCC_ABOVE)
}
'\u{0344}' => {
// COMBINING GREEK DIALYTIKA TONOS
buffer.push(CharacterAndClass::new('\u{0308}', CCC_ABOVE));
CharacterAndClass::new('\u{0301}', CCC_ABOVE)
}
'\u{0F73}' => {
// TIBETAN VOWEL SIGN II
buffer.push(CharacterAndClass::new('\u{0F71}', ccc!(CCC129, 129)));
CharacterAndClass::new('\u{0F72}', ccc!(CCC130, 130))
}
'\u{0F75}' => {
// TIBETAN VOWEL SIGN UU
buffer.push(CharacterAndClass::new('\u{0F71}', ccc!(CCC129, 129)));
CharacterAndClass::new('\u{0F74}', ccc!(CCC132, 132))
}
'\u{0F81}' => {
// TIBETAN VOWEL SIGN REVERSED II
buffer.push(CharacterAndClass::new('\u{0F71}', ccc!(CCC129, 129)));
CharacterAndClass::new('\u{0F80}', ccc!(CCC130, 130))
}
'\u{FF9E}' => {
// HALFWIDTH KATAKANA VOICED SOUND MARK
CharacterAndClass::new('\u{3099}', ccc!(KanaVoicing, 8))
}
'\u{FF9F}' => {
// HALFWIDTH KATAKANA VOICED SOUND MARK
CharacterAndClass::new('\u{309A}', ccc!(KanaVoicing, 8))
}
_ => {
// GIGO case
debug_assert!(false);
CharacterAndClass::new_with_placeholder(REPLACEMENT_CHARACTER)
}
};
buffer.push(mapped);
}
fn gather_and_sort_combining(&mut self, combining_start: usize) {
// Not a `for` loop to avoid holding a mutable reference to `self` across
// the loop body.
while let Some(ch_and_trie_val) = self.delegate_next() {
if !trie_value_has_ccc(ch_and_trie_val.trie_val) {
self.pending = Some(ch_and_trie_val);
break;
} else if !trie_value_indicates_special_non_starter_decomposition(
ch_and_trie_val.trie_val,
) {
self.buffer
.push(CharacterAndClass::new_with_trie_value(ch_and_trie_val));
} else {
Self::push_special_decomposition(&mut self.buffer, ch_and_trie_val.character);
}
}
// Slicing succeeds by construction; we've always ensured that `combining_start`
// is in permissible range.
#[expect(clippy::indexing_slicing)]
Self::sort_slice_by_ccc(&mut self.buffer[combining_start..], self.delegate.trie());
}
}
impl<'data, I, T, P> Iterator for DecompositionInner<'data, I, T, P>
where
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32>,
T: AbstractCodePointTrie<'data, u32> + 'data,
P: IteratorPolicy,
{
type Item = char;
#[inline]
fn next(&mut self) -> Option<char> {
if let Some(ret) = self.buffer.get(self.buffer_pos).map(|c| c.character()) {
self.buffer_pos += 1;
if self.buffer_pos == self.buffer.len() {
self.buffer.clear();
self.buffer_pos = 0;
}
return Some(ret);
}
debug_assert_eq!(self.buffer_pos, 0);
let c_and_trie_val = self.pending.take()?;
Some(self.decomposing_next(c_and_trie_val))
}
}
/// An iterator adaptor that turns an `Iterator` over `char` into
/// a lazily-decomposed and then canonically composed `char` sequence.
#[derive(Debug)]
pub struct Composition<'data, I>
where
I: Iterator<Item = char>,
{
inner: CompositionInner<
'data,
CharIterWithTrie<'data, Trie<'data>, u32, I>,
Trie<'data>,
Uax15Policy,
>,
}
impl<I> Iterator for Composition<'_, I>
where
I: Iterator<Item = char>,
{
type Item = char;
#[inline]
fn next(&mut self) -> Option<char> {
self.inner.next()
}
}
#[derive(Debug)]
struct CompositionInner<'data, I, T, P>
where
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32>,
T: AbstractCodePointTrie<'data, u32>,
P: IteratorPolicy,
{
/// The decomposing part of the normalizer than operates before
/// the canonical composition is performed on its output.
decomposition: DecompositionInner<'data, I, T, P>,
/// Non-Hangul canonical composition data.
canonical_compositions: CanonicalCompositionsRef<'data>,
/// To make `next()` yield in cases where there's a non-composing
/// starter in the decomposition buffer, we put it here to let it
/// wait for the next `next()` call (or a jump forward within the
/// `next()` call).
unprocessed_starter: Option<char>,
}
impl<'data, I, T, P> CompositionInner<'data, I, T, P>
where
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32>,
T: AbstractCodePointTrie<'data, u32>,
P: IteratorPolicy,
{
#[inline(always)]
fn new(
decomposition: DecompositionInner<'data, I, T, P>,
canonical_compositions: CanonicalCompositionsRef<'data>,
) -> Self {
Self {
decomposition,
canonical_compositions,
unprocessed_starter: None,
}
}
/// Performs canonical composition (including Hangul) on a pair of
/// characters or returns `None` if these characters don't compose.
/// Composition exclusions are taken into account.
#[inline(always)]
pub(crate) fn compose(&self, starter: char, second: char) -> Option<char> {
self.canonical_compositions.compose(starter, second)
}
/// Performs canonical composition (including Hangul) on a pair of
/// characters on the assumption that the second one is a starter
/// or returns `None` if these characters don't compose.
/// Composition exclusions are taken into account.
///
/// The returned boolean can be true only if `char` a Hangul LV syllable.
///
/// The argument `starter_is_lv` must be set either to false or to the value
/// that this method previously returned alongside `starter`.
#[inline(always)]
pub(crate) fn compose_starter(
&self,
starter: char,
second: char,
starter_is_lv: bool,
) -> Option<(char, bool)> {
self.canonical_compositions
.compose_starter(starter, second, starter_is_lv)
}
}
impl<'data, I, T, P> Iterator for CompositionInner<'data, I, T, P>
where
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32>,
T: AbstractCodePointTrie<'data, u32> + 'data,
P: IteratorPolicy,
{
type Item = char;
#[inline]
fn next(&mut self) -> Option<char> {
let mut undecomposed_starter = CharacterAndTrieValue::new('\u{0}', 0); // The compiler can't figure out that this gets overwritten before use.
if self.unprocessed_starter.is_none() {
// The loop is only broken out of as goto forward
#[expect(clippy::never_loop)]
loop {
if let Some((character, ccc)) = self
.decomposition
.buffer
.get(self.decomposition.buffer_pos)
.map(|c| c.character_and_ccc())
{
self.decomposition.buffer_pos += 1;
if self.decomposition.buffer_pos == self.decomposition.buffer.len() {
self.decomposition.buffer.clear();
self.decomposition.buffer_pos = 0;
}
if ccc == CCC_NOT_REORDERED {
// Previous decomposition contains a starter. This must
// now become the `unprocessed_starter` for it to have
// a chance to compose with the upcoming characters.
//
// E.g. parenthesized Hangul in NFKC comes through here,
// but suitable composition exclusion could exercise this
// in NFC.
self.unprocessed_starter = Some(character);
break; // We already have a starter, so skip taking one from `pending`.
}
return Some(character);
}
debug_assert_eq!(self.decomposition.buffer_pos, 0);
undecomposed_starter = self.decomposition.pending.take()?;
if undecomposed_starter.potential_passthrough() {
// TODO(#2385): In the NFC case (moot for NFKC and UTS46), if the upcoming
// character is not below `decomposition_passthrough_bound` but is
// below `composition_passthrough_bound`, we read from the trie
// unnecessarily.
if let Some(upcoming) = self.decomposition.delegate_next_no_pending() {
let cannot_combine_backwards = !upcoming.can_combine_backwards();
self.decomposition.pending = Some(upcoming);
if cannot_combine_backwards {
// Fast-track succeeded!
return Some(undecomposed_starter.character);
}
} else {
// End of stream
return Some(undecomposed_starter.character);
}
}
break; // Not actually looping
}
}
let mut starter = '\u{0}'; // The compiler can't figure out this gets overwritten before use.
// It would be fancier to bundle `starter` and `starter_is_lv` into an encapsulating
// struct, but that would result in lots of useless assignments to `starter_is_lv`.
// Using `debug_assert!(!starter_is_lv);` a lot instead.
let mut starter_is_lv = false;
// The point of having this boolean is to have only one call site to
// `self.decomposition.decomposing_next`, which is hopefully beneficial for
// code size under inlining.
let mut attempt_composition = false;
loop {
if let Some(unprocessed) = self.unprocessed_starter.take() {
debug_assert_eq!(undecomposed_starter, CharacterAndTrieValue::new('\u{0}', 0));
debug_assert_eq!(starter, '\u{0}');
debug_assert!(!starter_is_lv);
starter = unprocessed;
} else {
debug_assert_eq!(self.decomposition.buffer_pos, 0);
let next_starter = self.decomposition.decomposing_next(undecomposed_starter);
if !attempt_composition {
debug_assert!(!starter_is_lv);
starter = next_starter;
} else if let Some((composed, is_lv)) =
self.compose_starter(starter, next_starter, starter_is_lv)
{
// Normal non-enclosed Hangul is composed here.
starter_is_lv = is_lv;
starter = composed;
} else {
// This is our yield point. We'll pick this up above in the
// next call to `next()`.
self.unprocessed_starter = Some(next_starter);
return Some(starter);
}
}
// We first loop by index to avoid moving the contents of `buffer`, but
// if there's a discontiguous match, we'll start modifying `buffer` instead.
loop {
let (character, ccc) = if let Some((character, ccc)) = self
.decomposition
.buffer
.get(self.decomposition.buffer_pos)
.map(|c| c.character_and_ccc())
{
(character, ccc)
} else {
self.decomposition.buffer.clear();
self.decomposition.buffer_pos = 0;
break;
};
starter_is_lv = false;
// In NFKC, enclosed Hangul is recomposed here.
if let Some(composed) = self.compose(starter, character) {
debug_assert!(!starter_is_lv);
starter = composed;
self.decomposition.buffer_pos += 1;
continue;
}
let mut most_recent_skipped_ccc = ccc;
{
let _ = self
.decomposition
.buffer
.drain(0..self.decomposition.buffer_pos);
}
self.decomposition.buffer_pos = 0;
if most_recent_skipped_ccc == CCC_NOT_REORDERED {
// We failed to compose a starter. Discontiguous match not allowed.
// We leave the starter in `buffer` for `next()` to find.
return Some(starter);
}
// TODO: Make use of `compose` having figured out that no other matches are
// possible, either.
let mut i = 1; // We have skipped one non-starter.
while let Some((character, ccc)) = self
.decomposition
.buffer
.get(i)
.map(|c| c.character_and_ccc())
{
if ccc == CCC_NOT_REORDERED {
// Discontiguous match not allowed.
return Some(starter);
}
debug_assert!(ccc >= most_recent_skipped_ccc);
if ccc != most_recent_skipped_ccc {
// `character` is a non-starter, so we could use a variant of
// `compose` that omits all the Hangul cases.
// TODO: Make use of above `compose` having already done the trie lookup,
// so the linear slice could be reused here.
if let Some(composed) = self.compose(starter, character) {
self.decomposition.buffer.remove(i);
debug_assert!(!starter_is_lv);
starter = composed;
continue;
}
}
most_recent_skipped_ccc = ccc;
i += 1;
}
break;
}
debug_assert_eq!(self.decomposition.buffer_pos, 0);
if !self.decomposition.buffer.is_empty() {
return Some(starter);
}
// Now we need to check if composition with an upcoming starter is possible.
#[expect(clippy::unwrap_used)]
if self.decomposition.pending.is_some() {
// We know that `pending_starter` decomposes to start with a starter.
// Otherwise, it would have been moved to `self.decomposition.buffer`
// by `self.decomposing_next()`. We do this set lookup here in order
// to get an opportunity to go back to the fast track.
// Note that this check has to happen _after_ checking that `pending`
// holds a character, because this flag isn't defined to be meaningful
// when `pending` isn't holding a character.
let pending = self.decomposition.pending.as_ref().unwrap();
if !pending.can_combine_backwards() {
// Won't combine backwards anyway.
return Some(starter);
}
// Consume what we peeked. `unwrap` OK, because we checked `is_some()`
// above.
undecomposed_starter = self.decomposition.pending.take().unwrap();
// The following line is OK, because we're about to loop back
// to `self.decomposition.decomposing_next(c);`, which will
// restore the between-`next()`-calls invariant of `pending`
// before this function returns.
attempt_composition = true;
continue;
}
// End of input
return Some(starter);
}
}
}
macro_rules! composing_normalize_to {
($(#[$meta:meta])*,
$normalize_to:ident,
$write:path,
$slice:ty,
$prolog:block,
$always_valid_utf:literal,
$as_slice:ident,
$fast:block,
$text:ident,
$sink:ident,
$composition:ident,
$undecomposed_starter:ident,
$pending_slice:ident,
$len_utf:ident,
$self:ident,
$chars_with_trie:ident,
) => {
$(#[$meta])*
pub fn $normalize_to<W: $write + ?Sized>(
&$self,
$text: $slice,
$sink: &mut W,
) -> core::fmt::Result {
$prolog
let mut $composition = $self.normalize_iter_private::<_, Trie, Uax15Policy>($text.$chars_with_trie($self.trie()));
let _ = $composition.decomposition.init(); // Discard the U+0000.
for cc in $composition.decomposition.buffer.drain(..) {
$sink.write_char(cc.character())?;
}
'outer: loop {
debug_assert_eq!($composition.decomposition.buffer_pos, 0);
let mut $undecomposed_starter =
if let Some(pending) = $composition.decomposition.pending.take() {
pending
} else {
return Ok(());
};
if $undecomposed_starter.potential_passthrough()
{
// We don't know if a `REPLACEMENT_CHARACTER` occurred in the slice or
// was returned in response to an error by the iterator. Assume the
// latter for correctness even though it pessimizes the former.
if $always_valid_utf || $undecomposed_starter.character != REPLACEMENT_CHARACTER {
let $pending_slice = &$text[$text.len() - $composition.decomposition.delegate.$as_slice().len() - $undecomposed_starter.character.$len_utf()..];
// The `$fast` block must either:
// 1. Return due to reaching EOF
// 2. Leave a starter with its trie value in `$undecomposed_starter`
// and, if there is still more input, leave the next character
// and its trie value in `$composition.decomposition.pending`.
$fast
}
}
// Fast track above, full algorithm below
let mut starter = $composition
.decomposition
.decomposing_next($undecomposed_starter);
'bufferloop: loop {
// We first loop by index to avoid moving the contents of `buffer`, but
// if there's a discontiguous match, we'll start modifying `buffer` instead.
loop {
let (character, ccc) = if let Some((character, ccc)) = $composition
.decomposition
.buffer
.get($composition.decomposition.buffer_pos)
.map(|c| c.character_and_ccc())
{
(character, ccc)
} else {
$composition.decomposition.buffer.clear();
$composition.decomposition.buffer_pos = 0;
break;
};
// In NFKC, enclosed Hangul get recomposed here.
// Furthermore, in NFC if input has lv followed by t, lv gets
// decomposed above and recomposed here.
if let Some(composed) = $composition.compose(starter, character) {
starter = composed;
$composition.decomposition.buffer_pos += 1;
continue;
}
let mut most_recent_skipped_ccc = ccc;
if most_recent_skipped_ccc == CCC_NOT_REORDERED {
// We failed to compose a starter. Discontiguous match not allowed.
// Write the current `starter` we've been composing, make the unmatched
// starter in the buffer the new `starter` (we know it's been decomposed)
// and process the rest of the buffer with that as the starter.
$sink.write_char(starter)?;
starter = character;
$composition.decomposition.buffer_pos += 1;
continue 'bufferloop;
} else {
{
let _ = $composition
.decomposition
.buffer
.drain(0..$composition.decomposition.buffer_pos);
}
$composition.decomposition.buffer_pos = 0;
}
let mut i = 1; // We have skipped one non-starter.
while let Some((character, ccc)) = $composition
.decomposition
.buffer
.get(i)
.map(|c| c.character_and_ccc())
{
if ccc == CCC_NOT_REORDERED {
// Discontiguous match not allowed.
$sink.write_char(starter)?;
for cc in $composition.decomposition.buffer.drain(..i) {
$sink.write_char(cc.character())?;
}
starter = character;
{
let removed = $composition.decomposition.buffer.remove(0);
debug_assert_eq!(starter, removed.character());
}
debug_assert_eq!($composition.decomposition.buffer_pos, 0);
continue 'bufferloop;
}
debug_assert!(ccc >= most_recent_skipped_ccc);
if ccc != most_recent_skipped_ccc {
// `character` is a non-starter, so we could use a variant of
// `compose` that omits all the Hangul cases.
if let Some(composed) =
$composition.compose(starter, character)
{
$composition.decomposition.buffer.remove(i);
starter = composed;
continue;
}
}
most_recent_skipped_ccc = ccc;
i += 1;
}
break;
}
debug_assert_eq!($composition.decomposition.buffer_pos, 0);
if !$composition.decomposition.buffer.is_empty() {
$sink.write_char(starter)?;
for cc in $composition.decomposition.buffer.drain(..) {
$sink.write_char(cc.character())?;
}
// We had non-empty buffer, so can't compose with upcoming.
continue 'outer;
}
// We can loop back in case we compose a Hangul LV. Looping back
// makes this code much simpler than trying to have a special
// case that advances the underlying iterator in the branch that
// now says `continue;` below.
let mut starter_is_lv = false;
loop {
// Now we need to check if composition with an upcoming starter is possible.
if $composition.decomposition.pending.is_some() {
// We know that `pending_starter` decomposes to start with a starter.
// Otherwise, it would have been moved to `composition.decomposition.buffer`
// by `composition.decomposing_next()`. We do this set lookup here in order
// to get an opportunity to go back to the fast track.
// Note that this check has to happen _after_ checking that `pending`
// holds a character, because this flag isn't defined to be meaningful
// when `pending` isn't holding a character.
let pending = $composition.decomposition.pending.as_ref().unwrap();
if !pending.can_combine_backwards()
{
// Won't combine backwards anyway.
$sink.write_char(starter)?;
continue 'outer;
}
let pending_starter = $composition.decomposition.pending.take().unwrap();
let decomposed = $composition.decomposition.decomposing_next(pending_starter);
// Normal non-enclosed Hangul is composed here. The case where we have LV and T,
// but LV was not composed here previously is possible.
if let Some((composed, is_lv)) = $composition.compose_starter(starter, decomposed, starter_is_lv) {
starter = composed;
if is_lv && $composition.decomposition.buffer.is_empty() {
starter_is_lv = true;
// TODO: Put a Hangul fast-path that deals with conjoining jamo and ASCII
// in a manner specialized for the UTF (i.e. not doing surrogate checks,
// since surrogates are neither conjoining jamo nor ASCII) here.
continue;
}
} else {
$sink.write_char(starter)?;
starter = decomposed;
}
continue 'bufferloop;
}
break;
}
// End of input
$sink.write_char(starter)?;
return Ok(());
} // 'bufferloop
}
}
};
}
macro_rules! decomposing_normalize_to {
($(#[$meta:meta])*,
$normalize_to:ident,
$write:path,
$slice:ty,
$prolog:block,
$as_slice:ident,
$fast:block,
$text:ident,
$sink:ident,
$decomposition:ident,
$undecomposed_starter:ident,
$pending_slice:ident,
$outer:lifetime, // loop labels use lifetime tokens
$self:ident,
$chars_with_trie:ident,
) => {
$(#[$meta])*
pub fn $normalize_to<W: $write + ?Sized>(
&$self,
$text: $slice,
$sink: &mut W,
) -> core::fmt::Result {
$prolog
let mut $decomposition = $self.normalize_iter_private::<_, Trie, Uax15Policy>($text.$chars_with_trie($self.trie()));
let _ = $decomposition.init(); // Discard the U+0000.
$outer: loop {
for cc in $decomposition.buffer.drain(..) {
$sink.write_char(cc.character())?;
}
debug_assert_eq!($decomposition.buffer_pos, 0);
let mut $undecomposed_starter = if let Some(pending) = $decomposition.pending.take() {
pending
} else {
return Ok(());
};
loop {
if $undecomposed_starter.starter_and_decomposes_to_self() {
// Don't bother including `undecomposed_starter` in a contiguous buffer
// write: Just write it right away:
$sink.write_char($undecomposed_starter.character)?;
let $pending_slice = $decomposition.delegate.$as_slice();
$fast
}
debug_assert!($decomposition.pending.is_none());
let c_and_trie_val_unless_at_end = if let Some((upcoming, trie_val)) = $decomposition.delegate.next() {
if likely(!decomposition_starts_with_non_starter(trie_val)) {
Some(CharacterAndTrieValue::new(upcoming, trie_val))
} else {
$decomposition.pending = Some(CharacterAndTrieValue::new(upcoming, trie_val));
break;
}
} else {
None
};
// The upcoming character cannot sort into the tail of this decomposition,
// so, for performance, let's write decomposition directly here without
// going via `$decomposition.buffer`. This wall of (edited) copypaste is
// crucial for performance competitiveness with ICU4C.
// Start edited copypaste from `decomposing_next`
let c = $undecomposed_starter.character;
// See trie-value-format.md
let decomposition = $undecomposed_starter.trie_val;
// The REPLACEMENT CHARACTER has `NON_ROUND_TRIP_MARKER` set,
// and that flag needs to be ignored here.
if unlikely((decomposition & !(BACKWARD_COMBINING_MARKER | NON_ROUND_TRIP_MARKER)) == 0) {
// The character is its own decomposition
$sink.write_char(c)?;
} else {
let high_zeros = (decomposition & HIGH_ZEROS_MASK) == 0;
let low_zeros = (decomposition & LOW_ZEROS_MASK) == 0;
if !high_zeros && !low_zeros {
// Decomposition into two BMP characters: starter and non-starter
let starter = char_from_u32(decomposition & 0x7FFF);
let combining = char_from_u32((decomposition >> 15) & 0x7FFF);
$sink.write_char(starter)?;
$sink.write_char(combining)?;
} else if high_zeros {
// Do the check by looking at `c` instead of looking at a marker
// in `singleton` below, because if we looked at the trie value,
// we'd still have to check that `c` is in the Hangul syllable
// range in order for the subsequent interpretations as `char`
// to be safe.
// Alternatively, `FDFA_MARKER` and the Hangul marker could
// be unified. That would add a branch for Hangul and remove
// a branch from singleton decompositions. It seems more
// important to favor Hangul syllables than singleton
// decompositions.
// Note that it would be valid to hoist this Hangul check
// one or even two steps earlier in this check hierarchy.
// Right now, it's assumed the kind of decompositions into
// BMP starter and non-starter, which occur in many languages,
// should be checked before Hangul syllables, which are about
// one language specifically. Hopefully, we get some
// instruction-level parallelism out of the disjointness of
// operations on `c` and `decomposition`.
let hangul_offset = u32::from(c).wrapping_sub(HANGUL_S_BASE); // SIndex in the spec
if hangul_offset < HANGUL_S_COUNT {
debug_assert_eq!(decomposition, 1);
// Hangul syllable
// The math here comes from page 144 of Unicode 14.0
let l = hangul_offset / HANGUL_N_COUNT;
let v = (hangul_offset % HANGUL_N_COUNT) / HANGUL_T_COUNT;
let t = hangul_offset % HANGUL_T_COUNT;
// The unsafe blocks here are OK, because the values stay
// within the Hangul jamo block and, therefore, the scalar
// value range by construction.
$sink.write_char(unsafe { core::char::from_u32_unchecked(HANGUL_L_BASE + l) })?;
$sink.write_char(unsafe {
core::char::from_u32_unchecked(HANGUL_V_BASE + v)
})?;
if t != 0 {
$sink.write_char(unsafe {
core::char::from_u32_unchecked(HANGUL_T_BASE + t)
})?;
}
} else {
let singleton = decomposition as u16;
if singleton != FDFA_MARKER {
// Decomposition into one BMP character
let starter = char_from_u16(singleton);
$sink.write_char(starter)?;
} else {
// Special case for the NFKD form of U+FDFA.
$sink.write_char('\u{0635}')?;
for u in FDFA_NFKD {
// SAFETY: `FDFA_NFKD` is known not to contain
// surrogates.
$sink.write_char(unsafe { core::char::from_u32_unchecked(u32::from(u)) })?;
}
}
}
} else {
debug_assert!(low_zeros);
// Only 12 of 14 bits used as of Unicode 16.
let offset = (((decomposition & !(0b11 << 30)) >> 16) as usize) - 1;
// Only 3 of 4 bits used as of Unicode 16.
let len_bits = decomposition & 0b1111;
if let Some(subslice) = $decomposition.scalars16.get_subslice(offset..offset+((len_bits + 2) as usize)) {
for u in subslice.iter() {
$sink.write_char(char_from_u16(u))?;
}
} else {
let offset = offset - $decomposition.scalars16.len();
if let Some(subslice) = $decomposition.scalars24.get_subslice(offset..offset+((len_bits + 1) as usize)) {
for c in subslice.iter() {
$sink.write_char(c)?;
}
} else {
let offset = offset - $decomposition.scalars24.len();
if let Some(subslice) = $decomposition.supplementary_scalars16.get_subslice(offset..offset+((len_bits + 2) as usize)) {
for u in subslice.iter() {
$sink.write_char(char_from_u16(u))?;
}
} else {
let offset = offset - $decomposition.supplementary_scalars16.len();
if let Some(subslice) = $decomposition.supplementary_scalars24.get_subslice(offset..offset+((len_bits + 1) as usize)) {
for c in subslice.iter() {
$sink.write_char(c)?;
}
} else {
// GIGO case
debug_assert!(false);
}
}
}
}
}
}
// End edited copypaste from `decomposing_next`
if let Some(c_and_trie_val) = c_and_trie_val_unless_at_end {
$undecomposed_starter = c_and_trie_val;
continue;
}
return Ok(());
}
let starter = $decomposition.decomposing_next($undecomposed_starter);
$sink.write_char(starter)?;
}
}
};
}
macro_rules! normalizer_methods {
() => {
/// Normalize a string slice into a `Cow<'a, str>`.
pub fn normalize<'a>(&self, text: &'a str) -> Cow<'a, str> {
let (head, tail) = self.split_normalized(text);
if tail.is_empty() {
return Cow::Borrowed(head);
}
let mut ret = String::new();
ret.reserve(text.len());
ret.push_str(head);
let _ = self.normalize_to(tail, &mut ret);
Cow::Owned(ret)
}
/// Split a string slice into maximum normalized prefix and unnormalized suffix
/// such that the concatenation of the prefix and the normalization of the suffix
/// is the normalization of the whole input.
pub fn split_normalized<'a>(&self, text: &'a str) -> (&'a str, &'a str) {
let up_to = self.is_normalized_up_to(text);
text.split_at_checked(up_to).unwrap_or_else(|| {
// Internal bug, not even GIGO, never supposed to happen
debug_assert!(false);
("", text)
})
}
/// Return the index a string slice is normalized up to.
fn is_normalized_up_to(&self, text: &str) -> usize {
let mut sink = IsNormalizedSinkStr::new(text);
let _ = self.normalize_to(text, &mut sink);
text.len() - sink.remaining_len()
}
/// Check whether a string slice is normalized.
pub fn is_normalized(&self, text: &str) -> bool {
self.is_normalized_up_to(text) == text.len()
}
/// Normalize a slice of potentially-invalid UTF-16 into a `Cow<'a, [u16]>`.
///
/// Unpaired surrogates are mapped to the REPLACEMENT CHARACTER
/// before normalizing.
///
/// ✨ *Enabled with the `utf16_iter` Cargo feature.*
#[cfg(feature = "utf16_iter")]
pub fn normalize_utf16<'a>(&self, text: &'a [u16]) -> Cow<'a, [u16]> {
let (head, tail) = self.split_normalized_utf16(text);
if tail.is_empty() {
return Cow::Borrowed(head);
}
let mut ret = alloc::vec::Vec::with_capacity(text.len());
ret.extend_from_slice(head);
let _ = self.normalize_utf16_to(tail, &mut ret);
Cow::Owned(ret)
}
/// Split a slice of potentially-invalid UTF-16 into maximum normalized (and valid)
/// prefix and unnormalized suffix such that the concatenation of the prefix and the
/// normalization of the suffix is the normalization of the whole input.
///
/// ✨ *Enabled with the `utf16_iter` Cargo feature.*
#[cfg(feature = "utf16_iter")]
pub fn split_normalized_utf16<'a>(&self, text: &'a [u16]) -> (&'a [u16], &'a [u16]) {
let up_to = self.is_normalized_utf16_up_to(text);
text.split_at_checked(up_to).unwrap_or_else(|| {
// Internal bug, not even GIGO, never supposed to happen
debug_assert!(false);
(&[], text)
})
}
/// Return the index a slice of potentially-invalid UTF-16 is normalized up to.
///
/// ✨ *Enabled with the `utf16_iter` Cargo feature.*
#[cfg(feature = "utf16_iter")]
fn is_normalized_utf16_up_to(&self, text: &[u16]) -> usize {
let mut sink = IsNormalizedSinkUtf16::new(text);
let _ = self.normalize_utf16_to(text, &mut sink);
text.len() - sink.remaining_len()
}
/// Checks whether a slice of potentially-invalid UTF-16 is normalized.
///
/// Unpaired surrogates are treated as the REPLACEMENT CHARACTER.
///
/// ✨ *Enabled with the `utf16_iter` Cargo feature.*
#[cfg(feature = "utf16_iter")]
pub fn is_normalized_utf16(&self, text: &[u16]) -> bool {
self.is_normalized_utf16_up_to(text) == text.len()
}
/// Normalize a slice of potentially-invalid UTF-8 into a `Cow<'a, str>`.
///
/// Ill-formed byte sequences are mapped to the REPLACEMENT CHARACTER
/// according to the WHATWG Encoding Standard.
///
/// ✨ *Enabled with the `utf8_iter` Cargo feature.*
#[cfg(feature = "utf8_iter")]
pub fn normalize_utf8<'a>(&self, text: &'a [u8]) -> Cow<'a, str> {
let (head, tail) = self.split_normalized_utf8(text);
if tail.is_empty() {
return Cow::Borrowed(head);
}
let mut ret = String::new();
ret.reserve(text.len());
ret.push_str(head);
let _ = self.normalize_utf8_to(tail, &mut ret);
Cow::Owned(ret)
}
/// Split a slice of potentially-invalid UTF-8 into maximum normalized (and valid)
/// prefix and unnormalized suffix such that the concatenation of the prefix and the
/// normalization of the suffix is the normalization of the whole input.
///
/// ✨ *Enabled with the `utf8_iter` Cargo feature.*
#[cfg(feature = "utf8_iter")]
pub fn split_normalized_utf8<'a>(&self, text: &'a [u8]) -> (&'a str, &'a [u8]) {
let up_to = self.is_normalized_utf8_up_to(text);
let (head, tail) = text.split_at_checked(up_to).unwrap_or_else(|| {
// Internal bug, not even GIGO, never supposed to happen
debug_assert!(false);
(&[], text)
});
// SAFETY: The normalization check also checks for
// UTF-8 well-formedness.
(unsafe { core::str::from_utf8_unchecked(head) }, tail)
}
/// Return the index a slice of potentially-invalid UTF-8 is normalized up to
///
/// ✨ *Enabled with the `utf8_iter` Cargo feature.*
#[cfg(feature = "utf8_iter")]
fn is_normalized_utf8_up_to(&self, text: &[u8]) -> usize {
let mut sink = IsNormalizedSinkUtf8::new(text);
let _ = self.normalize_utf8_to(text, &mut sink);
text.len() - sink.remaining_len()
}
/// Check if a slice of potentially-invalid UTF-8 is normalized.
///
/// Ill-formed byte sequences are mapped to the REPLACEMENT CHARACTER
/// according to the WHATWG Encoding Standard before checking.
///
/// ✨ *Enabled with the `utf8_iter` Cargo feature.*
#[cfg(feature = "utf8_iter")]
pub fn is_normalized_utf8(&self, text: &[u8]) -> bool {
self.is_normalized_utf8_up_to(text) == text.len()
}
};
}
/// Borrowed version of a normalizer for performing decomposing normalization.
#[derive(Debug)]
pub struct DecomposingNormalizerBorrowed<'a> {
decompositions: &'a DecompositionData<'a>,
tables: &'a DecompositionTables<'a>,
supplementary_tables: Option<&'a DecompositionTables<'a>>,
decomposition_passthrough_bound: u8, // never above 0xC0
composition_passthrough_bound: u16, // never above 0x0300
}
impl DecomposingNormalizerBorrowed<'static> {
/// Cheaply converts a [`DecomposingNormalizerBorrowed<'static>`] into a [`DecomposingNormalizer`].
///
/// Note: Due to branching and indirection, using [`DecomposingNormalizer`] might inhibit some
/// compile-time optimizations that are possible with [`DecomposingNormalizerBorrowed`].
pub const fn static_to_owned(self) -> DecomposingNormalizer {
DecomposingNormalizer {
decompositions: DataPayload::from_static_ref(self.decompositions),
tables: DataPayload::from_static_ref(self.tables),
supplementary_tables: if let Some(s) = self.supplementary_tables {
// `map` not available in const context
Some(DataPayload::from_static_ref(s))
} else {
None
},
decomposition_passthrough_bound: self.decomposition_passthrough_bound,
composition_passthrough_bound: self.composition_passthrough_bound,
}
}
/// NFD constructor using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new_nfd() -> Self {
const _: () = assert!(
provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1
.scalars16
.const_len()
+ provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1
.scalars24
.const_len()
<= 0xFFF,
"future extension"
);
DecomposingNormalizerBorrowed {
decompositions: provider::Baked::SINGLETON_NORMALIZER_NFD_DATA_V1,
tables: provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1,
supplementary_tables: None,
decomposition_passthrough_bound: 0xC0,
composition_passthrough_bound: 0x0300,
}
}
/// NFKD constructor using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new_nfkd() -> Self {
const _: () = assert!(
provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1
.scalars16
.const_len()
+ provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1
.scalars24
.const_len()
+ provider::Baked::SINGLETON_NORMALIZER_NFKD_TABLES_V1
.scalars16
.const_len()
+ provider::Baked::SINGLETON_NORMALIZER_NFKD_TABLES_V1
.scalars24
.const_len()
<= 0xFFF,
"future extension"
);
// TODO: Perhaps hard-code these?
const _: () = assert!(
provider::Baked::SINGLETON_NORMALIZER_NFKD_DATA_V1.passthrough_cap <= 0x0300,
"invalid"
);
const _: () = assert!(
provider::Baked::SINGLETON_NORMALIZER_NFKD_DATA_V1.passthrough_cap >= 0x80,
"invalid"
);
let decomposition_capped =
if provider::Baked::SINGLETON_NORMALIZER_NFKD_DATA_V1.passthrough_cap < 0xC0 {
provider::Baked::SINGLETON_NORMALIZER_NFKD_DATA_V1.passthrough_cap
} else {
0xC0
};
let composition_capped =
if provider::Baked::SINGLETON_NORMALIZER_NFKD_DATA_V1.passthrough_cap < 0x0300 {
provider::Baked::SINGLETON_NORMALIZER_NFKD_DATA_V1.passthrough_cap
} else {
0x0300
};
DecomposingNormalizerBorrowed {
decompositions: provider::Baked::SINGLETON_NORMALIZER_NFKD_DATA_V1,
tables: provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1,
supplementary_tables: Some(provider::Baked::SINGLETON_NORMALIZER_NFKD_TABLES_V1),
decomposition_passthrough_bound: decomposition_capped as u8,
composition_passthrough_bound: composition_capped,
}
}
#[cfg(feature = "compiled_data")]
pub(crate) const fn new_uts46_decomposed() -> Self {
const _: () = assert!(
provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1
.scalars16
.const_len()
+ provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1
.scalars24
.const_len()
+ provider::Baked::SINGLETON_NORMALIZER_NFKD_TABLES_V1
.scalars16
.const_len()
+ provider::Baked::SINGLETON_NORMALIZER_NFKD_TABLES_V1
.scalars24
.const_len()
<= 0xFFF,
"future extension"
);
const _: () = assert!(
provider::Baked::SINGLETON_NORMALIZER_UTS46_DATA_V1.passthrough_cap <= 0x0300,
"invalid"
);
// Is less than 0x80!
let decomposition_capped =
if provider::Baked::SINGLETON_NORMALIZER_UTS46_DATA_V1.passthrough_cap < 0xC0 {
provider::Baked::SINGLETON_NORMALIZER_UTS46_DATA_V1.passthrough_cap
} else {
0xC0
};
let composition_capped =
if provider::Baked::SINGLETON_NORMALIZER_UTS46_DATA_V1.passthrough_cap < 0x0300 {
provider::Baked::SINGLETON_NORMALIZER_UTS46_DATA_V1.passthrough_cap
} else {
0x0300
};
DecomposingNormalizerBorrowed {
decompositions: provider::Baked::SINGLETON_NORMALIZER_UTS46_DATA_V1,
tables: provider::Baked::SINGLETON_NORMALIZER_NFD_TABLES_V1,
supplementary_tables: Some(provider::Baked::SINGLETON_NORMALIZER_NFKD_TABLES_V1),
decomposition_passthrough_bound: decomposition_capped as u8,
composition_passthrough_bound: composition_capped,
}
}
}
impl<'data> DecomposingNormalizerBorrowed<'data> {
/// NFD constructor using already-loaded data.
///
/// This constructor is intended for use by collations.
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[doc(hidden)]
pub fn new_with_data(
decompositions: &'data DecompositionData<'data>,
tables: &'data DecompositionTables<'data>,
) -> Self {
Self {
decompositions,
tables,
supplementary_tables: None,
decomposition_passthrough_bound: 0xC0,
composition_passthrough_bound: 0x0300,
}
}
/// Wraps a delegate iterator into a decomposing iterator
/// adapter by using the data already held by this normalizer.
#[inline]
pub fn normalize_iter<I: Iterator<Item = char>>(&self, iter: I) -> Decomposition<'data, I> {
let mut ret = Decomposition {
inner: self.normalize_iter_private(CharIterWithTrie::new(iter, self.trie())),
};
ret.inner.init(); // Discard the U+0000.
ret
}
/// There's an extra U+FFFD at the start. The caller must deal with it.
#[inline(always)]
fn normalize_iter_private<
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32>,
T: AbstractCodePointTrie<'data, u32> + 'data,
P: IteratorPolicy,
>(
&self,
iter: I,
) -> DecompositionInner<'data, I, T, P> {
DecompositionInner::new_with_supplements(iter, self.tables, self.supplementary_tables)
}
fn trie<T: AbstractCodePointTrie<'data, u32>>(&self) -> &'data T
where
&'data T: TryFrom<&'data CodePointTrie<'data, u32>>,
{
<&T>::try_from(&self.decompositions.trie)
.unwrap_or_else(|_| unreachable!("Incompatible data"))
}
normalizer_methods!();
decomposing_normalize_to!(
/// Normalize a string slice into a `Write` sink.
,
normalize_to,
core::fmt::Write,
&str,
{
},
as_str,
{
'fast: loop {
if let Some((mut upcoming, mut trie_val)) = decomposition.delegate.next() {
if starter_and_decomposes_to_self_impl(trie_val) {
continue 'fast;
}
// Try to handle a single combining mark followed by a starter in a way
// that avoids `decomposition.buffer`.
if likely(trie_value_indicates_non_decomposing_non_starter(trie_val)) {
// This loop is only broken out of as goto forward.
#[expect(clippy::never_loop)]
loop {
if let Some((after_mark, after_mark_trie_value)) = decomposition.delegate.next() {
if likely(starter_and_decomposes_to_self_impl(after_mark_trie_value)) {
continue 'fast;
}
if likely(!decomposition_starts_with_non_starter(after_mark_trie_value)) {
// We have a decomposing starter.
upcoming = after_mark;
trie_val = after_mark_trie_value;
break;
}
// We have another combining mark.
// We put the first combining mark, which we know doesn't decompose,
// directly into the buffer. We put the second one, which might decompose,
// into `decomposition.pending` for `gather_and_sort_combining` to deal
// with.
let consumed_so_far_slice = &pending_slice[..pending_slice.len()
- decomposition.delegate.as_str().len()
- upcoming.len_utf8()
- after_mark.len_utf8()];
sink.write_str(consumed_so_far_slice)?;
debug_assert!(decomposition.buffer.is_empty());
// Narrowing `trie_value` to `u8` is OK, because we already checked
// `decomposition_starts_with_non_starter`.
debug_assert!(trie_value_has_ccc(trie_val));
decomposition.buffer.push(CharacterAndClass::new(upcoming, CanonicalCombiningClass::from_icu4c_value(trie_val as u8)));
decomposition.pending = Some(CharacterAndTrieValue::new(after_mark, after_mark_trie_value));
decomposition.gather_and_sort_combining(0);
continue 'outer;
}
// End of stream
sink.write_str(pending_slice)?;
return Ok(());
}
}
// End skipping over single combining mark
let upcoming_with_trie_value = CharacterAndTrieValue::new(upcoming, trie_val);
let consumed_so_far_slice = &pending_slice[..pending_slice.len()
- decomposition.delegate.as_str().len()
- upcoming.len_utf8()];
sink.write_str(consumed_so_far_slice)?;
// Now let's figure out if we got a starter or a non-starter.
if decomposition_starts_with_non_starter(
trie_val,
) {
// Let this trie value to be reprocessed in case it is
// one of the rare decomposing ones.
decomposition.pending = Some(upcoming_with_trie_value);
decomposition.gather_and_sort_combining(0);
continue 'outer;
}
undecomposed_starter = upcoming_with_trie_value;
debug_assert!(decomposition.pending.is_none());
break 'fast;
}
// End of stream
sink.write_str(pending_slice)?;
return Ok(());
}
},
text,
sink,
decomposition,
undecomposed_starter,
pending_slice,
'outer,
self,
chars_with_trie_default_for_ascii,
);
decomposing_normalize_to!(
/// Normalize a slice of potentially-invalid UTF-8 into a `Write` sink.
///
/// Ill-formed byte sequences are mapped to the REPLACEMENT CHARACTER
/// according to the WHATWG Encoding Standard.
///
/// ✨ *Enabled with the `utf8_iter` Cargo feature.*
#[cfg(feature = "utf8_iter")]
,
normalize_utf8_to,
core::fmt::Write,
&[u8],
{
},
as_slice,
{
'fast: loop {
if let Some((mut upcoming, mut trie_val)) = decomposition.delegate.next() {
if starter_and_decomposes_to_self_except_replacement(trie_val) {
// Note: The trie value of the REPLACEMENT CHARACTER is
// intentionally formatted to fail the
// `starter_and_decomposes_to_self` test even though it
// really is a starter that decomposes to self. This
// Allows moving the branch on REPLACEMENT CHARACTER
// below this `continue`.
continue 'fast;
}
// Try to handle a single combining mark followed by a starter in a way
// that avoids `decomposition.buffer`.
if likely(trie_value_indicates_non_decomposing_non_starter(trie_val)) {
// This loop is only broken out of as goto forward.
#[expect(clippy::never_loop)]
loop {
if let Some((after_mark, after_mark_trie_value)) = decomposition.delegate.next() {
if likely(starter_and_decomposes_to_self_except_replacement(after_mark_trie_value)) {
continue 'fast;
}
if likely(!decomposition_starts_with_non_starter(after_mark_trie_value)) {
// We have a decomposing starter.
upcoming = after_mark;
trie_val = after_mark_trie_value;
break;
}
// We have another combining mark.
// We put the first combining mark, which we know doesn't decompose,
// directly into the buffer. We put the second one, which might decompose,
// into `decomposition.pending` for `gather_and_sort_combining` to deal
// with.
// `len_utf8` is OK, since knowing that we have two combining marks
// means that neither is U+FFFD, so we didn't have a UTF-8 error.
debug_assert_ne!(upcoming, '\u{FFFD}');
debug_assert_ne!(after_mark, '\u{FFFD}');
#[expect(clippy::indexing_slicing)]
let consumed_so_far_slice = &pending_slice[..pending_slice.len()
- decomposition.delegate.as_slice().len()
- upcoming.len_utf8()
- after_mark.len_utf8()];
sink.write_str(unsafe { core::str::from_utf8_unchecked(consumed_so_far_slice) } )?;
debug_assert!(decomposition.buffer.is_empty());
// Narrowing `trie_value` to `u8` is OK, because we already checked
// `decomposition_starts_with_non_starter`.
debug_assert!(trie_value_has_ccc(trie_val));
decomposition.buffer.push(CharacterAndClass::new(upcoming, CanonicalCombiningClass::from_icu4c_value(trie_val as u8)));
decomposition.pending = Some(CharacterAndTrieValue::new(after_mark, after_mark_trie_value));
decomposition.gather_and_sort_combining(0);
continue 'outer;
}
// End of stream
sink.write_str(unsafe { core::str::from_utf8_unchecked(pending_slice) } )?;
return Ok(());
}
}
// End skipping over single combining mark
let upcoming_with_trie_value = CharacterAndTrieValue::new(upcoming, trie_val);
if unlikely(upcoming == REPLACEMENT_CHARACTER) {
// We might have an error, so fall out of the fast path.
// Since the U+FFFD might signify an error, we can't
// assume `upcoming.len_utf8()` for the backoff length.
#[expect(clippy::indexing_slicing)]
let mut consumed_so_far = pending_slice[..pending_slice.len() - decomposition.delegate.as_slice().len()].chars();
let back = consumed_so_far.next_back();
debug_assert_eq!(back, Some(REPLACEMENT_CHARACTER));
let consumed_so_far_slice = consumed_so_far.as_slice();
sink.write_str(unsafe { core::str::from_utf8_unchecked(consumed_so_far_slice) } )?;
// We could call `gather_and_sort_combining` here and
// `continue 'outer`, but this should be better for code
// size.
undecomposed_starter = upcoming_with_trie_value;
debug_assert!(decomposition.pending.is_none());
break 'fast;
}
#[expect(clippy::indexing_slicing)]
let consumed_so_far_slice = &pending_slice[..pending_slice.len()
- decomposition.delegate.as_slice().len()
- upcoming.len_utf8()];
sink.write_str(unsafe { core::str::from_utf8_unchecked(consumed_so_far_slice) } )?;
// Now let's figure out if we got a starter or a non-starter.
if decomposition_starts_with_non_starter(
upcoming_with_trie_value.trie_val,
) {
// Let this trie value to be reprocessed in case it is
// one of the rare decomposing ones.
decomposition.pending = Some(upcoming_with_trie_value);
decomposition.gather_and_sort_combining(0);
continue 'outer;
}
undecomposed_starter = upcoming_with_trie_value;
debug_assert!(decomposition.pending.is_none());
break 'fast;
}
// End of stream
sink.write_str(unsafe { core::str::from_utf8_unchecked(pending_slice) } )?;
return Ok(());
}
},
text,
sink,
decomposition,
undecomposed_starter,
pending_slice,
'outer,
self,
chars_with_trie_default_for_ascii,
);
decomposing_normalize_to!(
/// Normalize a slice of potentially-invalid UTF-16 into a `Write16` sink.
///
/// Unpaired surrogates are mapped to the REPLACEMENT CHARACTER
/// before normalizing.
///
/// ✨ *Enabled with the `utf16_iter` Cargo feature.*
#[cfg(feature = "utf16_iter")]
,
normalize_utf16_to,
write16::Write16,
&[u16],
{
sink.size_hint(text.len())?;
},
as_slice,
{
// This loop is only broken out of as goto forward and only as release-build recovery from
// detecting an internal bug without panic. (In debug builds, internal bugs panic instead.)
#[expect(clippy::never_loop)]
'fastwrap: loop {
// Commented out `code_unit_iter` and used `ptr` and `end` to
//
// let mut code_unit_iter = decomposition.delegate.as_slice().iter();
let delegate_as_slice = decomposition.delegate.as_slice();
let mut ptr: *const u16 = delegate_as_slice.as_ptr();
// SAFETY: materializing a pointer immediately past the end of an
// allocation is OK.
let end: *const u16 = unsafe { ptr.add(delegate_as_slice.len()) };
let decomposition_passthrough_bound = u16::from(self.decomposition_passthrough_bound);
'fast: loop {
// if let Some(&upcoming_code_unit) = code_unit_iter.next() {
if likely(ptr != end) {
// SAFETY: We just checked that `ptr` has not reached `end`.
// `ptr` always advances by one, and we always have a check
// per advancement.
let upcoming_code_unit = unsafe { *ptr };
// SAFETY: Since `ptr` hadn't reached `end`, yet, advancing
// by one points to the same allocation or to immediately
// after, which is OK.
ptr = unsafe { ptr.add(1) };
// The performance of what logically is supposed to be this
// branch is _incredibly_ brittle and what LLVM ends up doing
// that affects the performance of what's logically about this
// decision can swing to double/halve the throughput for Basic
// Latin in ways that are completely unintuitive. Basically _any_
// change to _any_ code that participates in how LLVM sees the
// code around here can make the perf fall over. In seems that
// manually annotating this branch as likely has worse effects
// on non-Basic-Latin input that the case where LLVM just happens to
// do the right thing.
//
// What happens with this branch may depend on what sink type
// this code is monomorphized over.
//
// What a terrible sink of developer time!
if upcoming_code_unit < decomposition_passthrough_bound {
continue 'fast;
}
// We might be doing a trie lookup by surrogate. Surrogates get
// a decomposition to U+FFFD.
let mut trie_value = decomposition.delegate.trie().bmp(upcoming_code_unit);
if likely(starter_and_decomposes_to_self_impl(trie_value)) {
continue 'fast;
}
let mut upcoming32 = u32::from(upcoming_code_unit);
// We might now be looking at a surrogate.
// The loop is only broken out of as goto forward
#[expect(clippy::never_loop)]
'surrogateloop: loop {
// Try to handle a single BMP combining mark followed by a starter in a way
// that avoids `decomposition.buffer`. Crucial for perf competitiveness with ICU4C.
if likely(trie_value_indicates_non_decomposing_non_starter(trie_value)) {
if likely(ptr != end) {
// SAFETY: We just checked that `ptr` has not reached `end`.
// `ptr` always advances by one, and we always have a check
// per advancement.
let after_mark_code_unit = unsafe { *ptr };
// SAFETY: Since `ptr` hadn't reached `end`, yet, advancing
// by one points to the same allocation or to immediately
// after, which is OK.
ptr = unsafe { ptr.add(1) };
let after_mark_trie_value = decomposition.delegate.trie().bmp(after_mark_code_unit);
if likely(starter_and_decomposes_to_self_impl(after_mark_trie_value)) {
continue 'fast;
}
if unlikely(in_inclusive_range16(after_mark_code_unit, 0xD800, 0xDFFF)) {
// We have a surrogate. Too complicated to deal with, because
// it might be the first half of a combining mark.
// Pretend we didn't see it.
// SAFETY: We just incremented `ptr`, so decrementing it
// has to stay within the allocation.
ptr = unsafe { ptr.sub(1) };
break 'surrogateloop;
}
if likely(!decomposition_starts_with_non_starter(after_mark_trie_value)) {
// We have a decomposing starter.
// No need to sync `upcoming_code_unit`, since nothing reads it below.
upcoming32 = u32::from(after_mark_code_unit);
trie_value = after_mark_trie_value;
break 'surrogateloop;
}
// We have another combining mark.
// We put the first combining mark, which we know doesn't decompose,
// directly into the buffer. We put the second one, which might decompose,
// into `decomposition.pending` for `gather_and_sort_combining` to deal
// with.
let Some(consumed_so_far_slice) = pending_slice.get(..pending_slice.len() -
// code_unit_iter.as_slice().len()
// SAFETY: `ptr` and `end` have been derived from the same allocation
// and `ptr` is never greater than `end`.
unsafe { end.offset_from(ptr) as usize }
- 2) else {
// If we ever come here, it's a bug, but let's avoid panic code paths in release builds.
debug_assert!(false);
// Throw away the results of the fast path.
break 'fastwrap;
};
sink.write_slice(consumed_so_far_slice)?;
// Our belief that `upcoming32` is not a surrogate is based on trie data,
// which might be GIGO.
let upcoming = char_from_u32(upcoming32);
debug_assert!(decomposition.buffer.is_empty());
// Narrowing `trie_value` to `u8` is OK, because we already checked
// `decomposition_starts_with_non_starter`.
debug_assert!(trie_value_has_ccc(trie_value));
decomposition.buffer.push(CharacterAndClass::new(upcoming, CanonicalCombiningClass::from_icu4c_value(trie_value as u8)));
// Sync with main iterator
// SAFETY: `ptr` and `end` have been derived from the same allocation
// and `ptr` is never greater than `end`.
decomposition.delegate = unsafe { core::slice::from_raw_parts(ptr, end.offset_from(ptr) as usize) }.chars_with_trie(decomposition.delegate.trie());
// Let this trie value to be reprocessed in case it is
// one of the rare decomposing ones.
// SAFETY: We checked above that we don't have surrogate.
let after_mark_char = unsafe { char::from_u32_unchecked(u32::from(after_mark_code_unit))};
decomposition.pending = Some(CharacterAndTrieValue::new(after_mark_char, after_mark_trie_value));
decomposition.gather_and_sort_combining(0);
continue 'outer;
}
// End of stream
sink.write_slice(pending_slice)?;
return Ok(());
}
// End skipping over single combining mark
// LLVM's optimizations are incredibly brittle for the code _above_,
// and using `likely` _below_ without using it _above_ helps!
// What a massive sink of developer time!
// Seriously, the effect of these annotations is massively
// unintuitive. Measure everything!
// Notably, the `if likely(...)` formulation optimizes differently
// than just putting `cold_path()` on the `else` path!
let surrogate_base = upcoming32.wrapping_sub(0xD800);
if likely(surrogate_base > (0xDFFF - 0xD800)) {
// Not surrogate
break 'surrogateloop;
}
if likely(surrogate_base <= (0xDBFF - 0xD800)) {
// let iter_backup = code_unit_iter.clone();
// if let Some(&low) = code_unit_iter.next() {
if likely(ptr != end) {
// SAFETY: We just checked that `ptr` has not reached `end`.
// `ptr` always advances by one, and we always have a check
// per advancement.
let low = unsafe { *ptr };
if likely(in_inclusive_range16(low, 0xDC00, 0xDFFF)) {
// SAFETY: Since `ptr` hadn't reached `end`, yet, advancing
// by one points to the same allocation or to immediately
// after, which is OK.
ptr = unsafe { ptr.add(1) };
upcoming32 = (upcoming32 << 10) + u32::from(low)
- (((0xD800u32 << 10) - 0x10000u32) + 0xDC00u32);
// Successfully-paired surrogate. Read from the trie again.
trie_value = {
// Semantically, this bit of conditional compilation makes no sense.
// The purpose is to keep LLVM seeing the untyped trie case the way
// it did before so as not to regress the performance of the untyped
// case due to unintuitive optimizer effects. If you care about the
// perf of the untyped trie case and have better ideas, please try
// something better.
#[cfg(feature = "serde")]
{decomposition.delegate.trie().code_point(upcoming32)}
#[cfg(not(feature = "serde"))]
{decomposition.delegate.trie().supplementary(upcoming32)}
};
if likely(starter_and_decomposes_to_self_impl(trie_value)) {
continue 'fast;
}
break 'surrogateloop;
// } else {
// code_unit_iter = iter_backup;
}
}
}
// unpaired surrogate
upcoming32 = 0xFFFD; // Safe value for `char::from_u32_unchecked` and matches later potential error check.
// trie_value already holds a decomposition to U+FFFD.
break 'surrogateloop;
}
let upcoming = unsafe { char::from_u32_unchecked(upcoming32) };
let upcoming_with_trie_value = CharacterAndTrieValue::new(upcoming, trie_value);
let Some(consumed_so_far_slice) = pending_slice.get(..pending_slice.len() -
// code_unit_iter.as_slice().len()
// SAFETY: `ptr` and `end` have been derived from the same allocation
// and `ptr` is never greater than `end`.
unsafe { end.offset_from(ptr) as usize }
- upcoming.len_utf16()) else {
// If we ever come here, it's a bug, but let's avoid panic code paths in release builds.
debug_assert!(false);
// Throw away the results of the fast path.
break 'fastwrap;
};
sink.write_slice(consumed_so_far_slice)?;
if decomposition_starts_with_non_starter(
upcoming_with_trie_value.trie_val,
) {
// Sync with main iterator
// decomposition.delegate = code_unit_iter.as_slice().chars();
// SAFETY: `ptr` and `end` have been derived from the same allocation
// and `ptr` is never greater than `end`.
decomposition.delegate = unsafe { core::slice::from_raw_parts(ptr, end.offset_from(ptr) as usize) }.chars_with_trie(decomposition.delegate.trie());
// Let this trie value to be reprocessed in case it is
// one of the rare decomposing ones.
decomposition.pending = Some(upcoming_with_trie_value);
decomposition.gather_and_sort_combining(0);
continue 'outer;
}
undecomposed_starter = upcoming_with_trie_value;
debug_assert!(decomposition.pending.is_none());
break 'fast;
}
// End of stream
sink.write_slice(pending_slice)?;
return Ok(());
}
// Sync the main iterator
// decomposition.delegate = code_unit_iter.as_slice().chars();
// SAFETY: `ptr` and `end` have been derived from the same allocation
// and `ptr` is never greater than `end`.
decomposition.delegate = unsafe { core::slice::from_raw_parts(ptr, end.offset_from(ptr) as usize) }.chars_with_trie(decomposition.delegate.trie());
break 'fastwrap;
}
},
text,
sink,
decomposition,
undecomposed_starter,
pending_slice,
'outer,
self,
chars_with_trie,
);
}
/// A normalizer for performing decomposing normalization.
#[derive(Debug)]
pub struct DecomposingNormalizer {
decompositions: DataPayload<NormalizerNfdDataV1>,
tables: DataPayload<NormalizerNfdTablesV1>,
supplementary_tables: Option<DataPayload<NormalizerNfkdTablesV1>>,
decomposition_passthrough_bound: u8, // never above 0xC0
composition_passthrough_bound: u16, // never above 0x0300
}
impl DecomposingNormalizer {
/// Constructs a borrowed version of this type for more efficient querying.
pub fn as_borrowed(&self) -> DecomposingNormalizerBorrowed<'_> {
DecomposingNormalizerBorrowed {
decompositions: self.decompositions.get(),
tables: self.tables.get(),
supplementary_tables: self.supplementary_tables.as_ref().map(|s| s.get()),
decomposition_passthrough_bound: self.decomposition_passthrough_bound,
composition_passthrough_bound: self.composition_passthrough_bound,
}
}
/// NFD constructor using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new_nfd() -> DecomposingNormalizerBorrowed<'static> {
DecomposingNormalizerBorrowed::new_nfd()
}
icu_provider::gen_buffer_data_constructors!(
() -> error: DataError,
functions: [
new_nfd: skip,
try_new_nfd_with_buffer_provider,
try_new_nfd_unstable,
Self,
]
);
#[doc = icu_provider::gen_buffer_unstable_docs!(UNSTABLE, Self::new_nfd)]
pub fn try_new_nfd_unstable<D>(provider: &D) -> Result<Self, DataError>
where
D: DataProvider<NormalizerNfdDataV1> + DataProvider<NormalizerNfdTablesV1> + ?Sized,
{
let decompositions: DataPayload<NormalizerNfdDataV1> =
provider.load(Default::default())?.payload;
let tables: DataPayload<NormalizerNfdTablesV1> = provider.load(Default::default())?.payload;
if tables.get().scalars16.len() + tables.get().scalars24.len() > 0xFFF {
// The data is from a future where there exists a normalization flavor whose
// complex decompositions take more than 0xFFF but fewer than 0x1FFF code points
// of space. If a good use case from such a decomposition flavor arises, we can
// dynamically change the bit masks so that the length mask becomes 0x1FFF instead
// of 0xFFF and the all-non-starters mask becomes 0 instead of 0x1000. However,
// since for now the masks are hard-coded, error out.
return Err(
DataError::custom("future extension").with_marker(NormalizerNfdTablesV1::INFO)
);
}
let cap = decompositions.get().passthrough_cap;
if cap > 0x0300 {
return Err(DataError::custom("invalid").with_marker(NormalizerNfdDataV1::INFO));
}
if cap < 0x80 {
return Err(DataError::custom("invalid").with_marker(NormalizerNfdDataV1::INFO));
}
let decomposition_capped = cap.min(0xC0);
let composition_capped = cap.min(0x0300);
Ok(DecomposingNormalizer {
decompositions,
tables,
supplementary_tables: None,
decomposition_passthrough_bound: decomposition_capped as u8,
composition_passthrough_bound: composition_capped,
})
}
icu_provider::gen_buffer_data_constructors!(
() -> error: DataError,
functions: [
new_nfkd: skip,
try_new_nfkd_with_buffer_provider,
try_new_nfkd_unstable,
Self,
]
);
/// NFKD constructor using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new_nfkd() -> DecomposingNormalizerBorrowed<'static> {
DecomposingNormalizerBorrowed::new_nfkd()
}
#[doc = icu_provider::gen_buffer_unstable_docs!(UNSTABLE, Self::new_nfkd)]
pub fn try_new_nfkd_unstable<D>(provider: &D) -> Result<Self, DataError>
where
D: DataProvider<NormalizerNfkdDataV1>
+ DataProvider<NormalizerNfdTablesV1>
+ DataProvider<NormalizerNfkdTablesV1>
+ ?Sized,
{
let decompositions: DataPayload<NormalizerNfkdDataV1> =
provider.load(Default::default())?.payload;
let tables: DataPayload<NormalizerNfdTablesV1> = provider.load(Default::default())?.payload;
let supplementary_tables: DataPayload<NormalizerNfkdTablesV1> =
provider.load(Default::default())?.payload;
if tables.get().scalars16.len()
+ tables.get().scalars24.len()
+ supplementary_tables.get().scalars16.len()
+ supplementary_tables.get().scalars24.len()
> 0xFFF
{
// The data is from a future where there exists a normalization flavor whose
// complex decompositions take more than 0xFFF but fewer than 0x1FFF code points
// of space. If a good use case from such a decomposition flavor arises, we can
// dynamically change the bit masks so that the length mask becomes 0x1FFF instead
// of 0xFFF and the all-non-starters mask becomes 0 instead of 0x1000. However,
// since for now the masks are hard-coded, error out.
return Err(
DataError::custom("future extension").with_marker(NormalizerNfdTablesV1::INFO)
);
}
let cap = decompositions.get().passthrough_cap;
if cap > 0x0300 {
return Err(DataError::custom("invalid").with_marker(NormalizerNfkdDataV1::INFO));
}
if cap < 0x80 {
return Err(DataError::custom("invalid").with_marker(NormalizerNfdDataV1::INFO));
}
let decomposition_capped = cap.min(0xC0);
let composition_capped = cap.min(0x0300);
Ok(DecomposingNormalizer {
decompositions: decompositions.cast(),
tables,
supplementary_tables: Some(supplementary_tables),
decomposition_passthrough_bound: decomposition_capped as u8,
composition_passthrough_bound: composition_capped,
})
}
/// UTS 46 decomposed constructor (testing only)
///
/// This is a special building block normalization for IDNA. It is the decomposed counterpart of
/// ICU4C's UTS 46 normalization with two exceptions: characters that UTS 46 disallows and
/// ICU4C maps to U+FFFD and characters that UTS 46 maps to the empty string normalize as in
/// NFD in this normalization. In both cases, the previous UTS 46 processing before using
/// normalization is expected to deal with these characters. Making the disallowed characters
/// behave like this is beneficial to data size, and this normalizer implementation cannot
/// deal with a character normalizing to the empty string, which doesn't happen in NFD or
/// NFKD as of Unicode 14.
///
/// Warning: In this normalization, U+0345 COMBINING GREEK YPOGEGRAMMENI exhibits a behavior
/// that no character in Unicode exhibits in NFD, NFKD, NFC, or NFKC: Case folding turns
/// U+0345 from a reordered character into a non-reordered character before reordering happens.
/// Therefore, the output of this normalization may differ for different inputs that are
/// canonically equivalent with each other if they differ by how U+0345 is ordered relative
/// to other reorderable characters.
pub(crate) fn try_new_uts46_decomposed_unstable<D>(provider: &D) -> Result<Self, DataError>
where
D: DataProvider<NormalizerUts46DataV1>
+ DataProvider<NormalizerNfdTablesV1>
+ DataProvider<NormalizerNfkdTablesV1>
// UTS 46 tables merged into CompatibilityDecompositionTablesV1
+ ?Sized,
{
let decompositions: DataPayload<NormalizerUts46DataV1> =
provider.load(Default::default())?.payload;
let tables: DataPayload<NormalizerNfdTablesV1> = provider.load(Default::default())?.payload;
let supplementary_tables: DataPayload<NormalizerNfkdTablesV1> =
provider.load(Default::default())?.payload;
if tables.get().scalars16.len()
+ tables.get().scalars24.len()
+ supplementary_tables.get().scalars16.len()
+ supplementary_tables.get().scalars24.len()
> 0xFFF
{
// The data is from a future where there exists a normalization flavor whose
// complex decompositions take more than 0xFFF but fewer than 0x1FFF code points
// of space. If a good use case from such a decomposition flavor arises, we can
// dynamically change the bit masks so that the length mask becomes 0x1FFF instead
// of 0xFFF and the all-non-starters mask becomes 0 instead of 0x1000. However,
// since for now the masks are hard-coded, error out.
return Err(
DataError::custom("future extension").with_marker(NormalizerNfdTablesV1::INFO)
);
}
let cap = decompositions.get().passthrough_cap;
if cap > 0x0300 {
return Err(DataError::custom("invalid").with_marker(NormalizerUts46DataV1::INFO));
}
// Can be below 0x80!
let decomposition_capped = cap.min(0xC0);
let composition_capped = cap.min(0x0300);
Ok(DecomposingNormalizer {
decompositions: decompositions.cast(),
tables,
supplementary_tables: Some(supplementary_tables),
decomposition_passthrough_bound: decomposition_capped as u8,
composition_passthrough_bound: composition_capped,
})
}
}
/// Borrowed version of a normalizer for performing composing normalization.
#[derive(Debug)]
pub struct ComposingNormalizerBorrowed<'a> {
decomposing_normalizer: DecomposingNormalizerBorrowed<'a>,
canonical_compositions: CanonicalCompositionsBorrowed<'a>,
}
impl ComposingNormalizerBorrowed<'static> {
/// Cheaply converts a [`ComposingNormalizerBorrowed<'static>`] into a [`ComposingNormalizer`].
///
/// Note: Due to branching and indirection, using [`ComposingNormalizer`] might inhibit some
/// compile-time optimizations that are possible with [`ComposingNormalizerBorrowed`].
pub const fn static_to_owned(self) -> ComposingNormalizer {
ComposingNormalizer {
decomposing_normalizer: self.decomposing_normalizer.static_to_owned(),
canonical_compositions: self.canonical_compositions.static_to_owned(),
}
}
/// NFC constructor using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new_nfc() -> Self {
ComposingNormalizerBorrowed {
decomposing_normalizer: DecomposingNormalizerBorrowed::new_nfd(),
canonical_compositions: CanonicalCompositionsBorrowed::Current(
provider::Baked::SINGLETON_NORMALIZER_NFC_V2,
),
}
}
/// NFKC constructor using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new_nfkc() -> Self {
ComposingNormalizerBorrowed {
decomposing_normalizer: DecomposingNormalizerBorrowed::new_nfkd(),
canonical_compositions: CanonicalCompositionsBorrowed::Current(
provider::Baked::SINGLETON_NORMALIZER_NFC_V2,
),
}
}
/// This is a special building block normalization for IDNA that implements parts of the Map
/// step and the following Normalize step.
///
/// Warning: In this normalization, U+0345 COMBINING GREEK YPOGEGRAMMENI exhibits a behavior
/// that no character in Unicode exhibits in NFD, NFKD, NFC, or NFKC: Case folding turns
/// U+0345 from a reordered character into a non-reordered character before reordering happens.
/// Therefore, the output of this normalization may differ for different inputs that are
/// canonically equivalents with each other if they differ by how U+0345 is ordered relative
/// to other reorderable characters.
#[cfg(feature = "compiled_data")]
pub(crate) const fn new_uts46() -> Self {
ComposingNormalizerBorrowed {
decomposing_normalizer: DecomposingNormalizerBorrowed::new_uts46_decomposed(),
canonical_compositions: CanonicalCompositionsBorrowed::Current(
provider::Baked::SINGLETON_NORMALIZER_NFC_V2,
),
}
}
}
impl<'data> ComposingNormalizerBorrowed<'data> {
/// Wraps a delegate iterator into a composing iterator
/// adapter by using the data already held by this normalizer.
#[inline]
pub fn normalize_iter<I: Iterator<Item = char>>(&'data self, iter: I) -> Composition<'data, I> {
let mut ret = Composition {
inner: self.normalize_iter_private(CharIterWithTrie::new(iter, self.trie())),
};
ret.inner.decomposition.init(); // Discard the U+0000.
ret
}
/// There's an extra U+FFFD at the start. The caller must deal with it.
#[inline(always)]
fn normalize_iter_private<
I: Iterator<Item = (char, u32)> + WithTrie<'data, T, u32>,
T: AbstractCodePointTrie<'data, u32> + 'data,
P: IteratorPolicy,
>(
&'data self,
iter: I,
) -> CompositionInner<'data, I, T, P> {
CompositionInner::new(
DecompositionInner::new_with_supplements(
iter,
self.decomposing_normalizer.tables,
self.decomposing_normalizer.supplementary_tables,
),
self.canonical_compositions.as_ref(),
)
}
fn trie<T: AbstractCodePointTrie<'data, u32>>(&self) -> &'data T
where
&'data T: TryFrom<&'data CodePointTrie<'data, u32>>,
{
self.decomposing_normalizer.trie()
}
normalizer_methods!();
composing_normalize_to!(
/// Normalize a string slice into a `Write` sink.
,
normalize_to,
core::fmt::Write,
&str,
{},
true,
as_str,
{
let composition_passthrough_byte_bound = if self.decomposing_normalizer.composition_passthrough_bound == 0x300 {
0xCCu8
} else {
// We can make this fancy if a normalization other than NFC where looking at
// non-ASCII lead bytes is worthwhile is ever introduced.
self.decomposing_normalizer.composition_passthrough_bound.min(0x80) as u8
};
// Attributes have to be on blocks, so hoisting all the way here.
let mut code_unit_iter = composition.decomposition.delegate.as_str().as_bytes().iter();
'fast: loop {
if let Some(b) = code_unit_iter.next() {
let upcoming_byte = *b;
if upcoming_byte < composition_passthrough_byte_bound {
// Fast-track succeeded!
continue 'fast;
}
// Begin manual inlining from `CharsWithTrie`
// SAFETY: Since `code_unit_iter` came from `str` and we always advance by a full UTF-8 sequence, we may assume that we
// have a valid lead byte. We can assume that the lead byte won't be ASCII, because `composition_passthrough_byte_bound`
// is never less than 0x80. Not need to check for other cases.
let (upcoming, trie_val) = if upcoming_byte < 0xE0 {
// Two-byte sequence.
// SAFETY, since `code_unit_iter` came from `str` and we always advance by a full UTF-8 sequence, we may assume the
// presence of a trail byte.
let trail = *unsafe { code_unit_iter.next().unwrap_unchecked() };
let high_five = u32::from(upcoming_byte & 0b11_111);
let low_six = u32::from(trail & 0b111_111);
// SAFETY: By construction, `high_five` and `low_six` conform
// to the invariant of `utf8_two_byte`.
let v = unsafe { composition.decomposition.delegate.trie().utf8_two_byte(high_five, low_six) };
// SAFETY: Since `code_unit_iter` came from `str` and we always advance by a full UTF-8 sequence, `lead` must be a
// valid (not overlong) two-byte lead and `trail` must be a valid
// trail. Therefore, the following shift and OR stays in the
// scalar value range.
let c = unsafe { char::from_u32_unchecked((high_five << 6) | low_six) };
(c, v)
} else if upcoming_byte < 0xF0 {
// Three-byte sequence.
// SAFETY, since `code_unit_iter` came from `str` and we always advance by a full UTF-8 sequence, we may assume the
// presence of two trail bytes.
let second = *unsafe { code_unit_iter.next().unwrap_unchecked() };
let third = *unsafe { code_unit_iter.next().unwrap_unchecked() };
let high_ten = (u32::from(upcoming_byte & 0b1111) << 6) | u32::from(second & 0b111_111);
let low_six = u32::from(third & 0b111_111);
// SAFETY: By construction, `high_ten` and `low_six` conform
// to the invariant of `utf8_three_byte`.
let v = unsafe { composition.decomposition.delegate.trie().utf8_three_byte(high_ten, low_six) };
// SAFETY: Since `code_unit_iter` came from `str` and we always advance by a full UTF-8 sequence, `lead` must be a
// valid (not overlong) three-byte lead and `second` and `third`
// must be valid trails. Therefore, the following shift and OR
// stays in the scalar value range.
let c = unsafe { char::from_u32_unchecked((high_ten << 6) | low_six) };
(c, v)
} else {
// Four-byte sequence
// SAFETY, since `code_unit_iter` came from `str` and we always advance by a full UTF-8 sequence, we may assume the
// presence of three trail bytes.
let second = *unsafe { code_unit_iter.next().unwrap_unchecked() };
let third = *unsafe { code_unit_iter.next().unwrap_unchecked() };
let fourth = *unsafe { code_unit_iter.next().unwrap_unchecked() };
// SAFETY: Since `code_unit_iter` came from `str` and we always advance by a full UTF-8 sequence, `lead` must be a
// valid (not overlong or out-of-range) four-byte lead and `second`,
// `third`, and `fourth` must be valid trails. Therefore, the
// following shift and OR stays in the scalar value range.
let c = unsafe {
char::from_u32_unchecked(
(u32::from(upcoming_byte & 0b111) << 18)
| (u32::from(second & 0b111_111) << 12)
| (u32::from(third & 0b111_111) << 6)
| u32::from(fourth & 0b111_111),
)
};
(c, composition.decomposition.delegate.trie().supplementary(c as u32))
};
// End manual inlining from `CharsWithTrie`
if potential_passthrough_and_cannot_combine_backwards(trie_val) {
continue 'fast;
}
// SAFETY: We've advanced `code_unit_iter` to a UTF-8 boundary.
composition.decomposition.delegate = unsafe { core::str::from_utf8_unchecked(code_unit_iter.as_slice())}.chars_with_trie_default_for_ascii(composition.decomposition.delegate.trie());
let upcoming_with_trie_value = CharacterAndTrieValue::new(upcoming, trie_val);
// We need to fall off the fast path.
composition.decomposition.pending = Some(upcoming_with_trie_value);
// slicing and unwrap OK, because we've just evidently read enough previously.
let mut consumed_so_far = pending_slice[..pending_slice.len() - composition.decomposition.delegate.as_str().len() - upcoming.len_utf8()].chars_with_trie_default_for_ascii(composition.decomposition.delegate.trie());
// Whether we could do something better than `next_back()` below is
// `unwrap` OK, because we've previously manage to read the previous character
#[expect(clippy::unwrap_used)]
let (undecomposed, undecomposed_trie_val) = consumed_so_far.next_back().unwrap();
undecomposed_starter = CharacterAndTrieValue::new(undecomposed, undecomposed_trie_val);
let consumed_so_far_slice = consumed_so_far.as_str();
sink.write_str(consumed_so_far_slice)?;
break 'fast;
}
// End of stream
sink.write_str(pending_slice)?;
return Ok(());
}
},
text,
sink,
composition,
undecomposed_starter,
pending_slice,
len_utf8,
self,
chars_with_trie_default_for_ascii,
);
composing_normalize_to!(
/// Normalize a slice of potentially-invalid UTF-8 into a `Write` sink.
///
/// Ill-formed byte sequences are mapped to the REPLACEMENT CHARACTER
/// according to the WHATWG Encoding Standard.
///
/// ✨ *Enabled with the `utf8_iter` Cargo feature.*
#[cfg(feature = "utf8_iter")]
,
normalize_utf8_to,
core::fmt::Write,
&[u8],
{},
false,
as_slice,
{
'fast: loop {
if let Some((upcoming, trie_val)) = composition.decomposition.delegate.next() {
if potential_passthrough_and_cannot_combine_backwards(trie_val) {
// Note: The trie value of the REPLACEMENT CHARACTER is
// intentionally formatted to fail the
// `potential_passthrough_and_cannot_combine_backwards`
// test even though it really is a starter that decomposes
// to self and cannot combine backwards. This
// Allows moving the branch on REPLACEMENT CHARACTER
// below this `continue`.
continue 'fast;
}
// We need to fall off the fast path.
let upcoming_with_trie_value = CharacterAndTrieValue::new(upcoming, trie_val);
if unlikely(upcoming == REPLACEMENT_CHARACTER) {
// Can't tell if this is an error or a literal U+FFFD in
// the input. Assuming the former to be sure.
// Since the U+FFFD might signify an error, we can't
// assume `upcoming.len_utf8()` for the backoff length.
#[expect(clippy::indexing_slicing)]
let mut consumed_so_far = pending_slice[..pending_slice.len() - composition.decomposition.delegate.as_slice().len()].chars();
let back = consumed_so_far.next_back();
debug_assert_eq!(back, Some(REPLACEMENT_CHARACTER));
let consumed_so_far_slice = consumed_so_far.as_slice();
sink.write_str(unsafe { core::str::from_utf8_unchecked(consumed_so_far_slice) })?;
undecomposed_starter = CharacterAndTrieValue::new(REPLACEMENT_CHARACTER, 0);
composition.decomposition.pending = None;
break 'fast;
}
composition.decomposition.pending = Some(upcoming_with_trie_value);
// slicing and unwrap OK, because we've just evidently read enough previously.
// `unwrap` OK, because we've previously manage to read the previous character
#[expect(clippy::indexing_slicing)]
let mut consumed_so_far = pending_slice[..pending_slice.len() - composition.decomposition.delegate.as_slice().len() - upcoming.len_utf8()].chars_with_trie_default_for_ascii(composition.decomposition.delegate.trie());
#[expect(clippy::unwrap_used)]
{
// Whether we could do something better than `next_back()` below is
let (undecomposed, undecomposed_trie_val) = consumed_so_far.next_back().unwrap();
undecomposed_starter = CharacterAndTrieValue::new(undecomposed, undecomposed_trie_val);
}
let consumed_so_far_slice = consumed_so_far.as_slice();
sink.write_str(unsafe { core::str::from_utf8_unchecked(consumed_so_far_slice)})?;
break 'fast;
}
// End of stream
sink.write_str(unsafe { core::str::from_utf8_unchecked(pending_slice) })?;
return Ok(());
}
},
text,
sink,
composition,
undecomposed_starter,
pending_slice,
len_utf8,
self,
chars_with_trie_default_for_ascii,
);
composing_normalize_to!(
/// Normalize a slice of potentially-invalid UTF-16 into a `Write16` sink.
///
/// Unpaired surrogates are mapped to the REPLACEMENT CHARACTER
/// before normalizing.
///
/// ✨ *Enabled with the `utf16_iter` Cargo feature.*
#[cfg(feature = "utf16_iter")]
,
normalize_utf16_to,
write16::Write16,
&[u16],
{
sink.size_hint(text.len())?;
},
false,
as_slice,
{
// This loop is only broken out of as goto forward and only as release-build recovery from
// detecting an internal bug without panic. (In debug builds, internal bugs panic instead.)
#[expect(clippy::never_loop)]
'fastwrap: loop {
// Commented out `code_unit_iter` and used `ptr` and `end` to
//
// let mut code_unit_iter = composition.decomposition.delegate.as_slice().iter();
let delegate_as_slice = composition.decomposition.delegate.as_slice();
let mut ptr: *const u16 = delegate_as_slice.as_ptr();
// SAFETY: materializing a pointer immediately past the end of an
// allocation is OK.
let end: *const u16 = unsafe { ptr.add(delegate_as_slice.len()) };
let composition_passthrough_bound = self.decomposing_normalizer.composition_passthrough_bound;
'fast: loop {
// Only broken out of as goto forward
'end: loop {
// if let Some(&upcoming_code_unit) = code_unit_iter.next() {
if likely(ptr != end) {
// SAFETY: We just checked that `ptr` has not reached `end`.
// `ptr` always advances by one, and we always have a check
// per advancement.
let mut upcoming_code_unit = unsafe { *ptr };
// SAFETY: Since `ptr` hadn't reached `end`, yet, advancing
// by one points to the same allocation or to immediately
// after, which is OK.
ptr = unsafe { ptr.add(1) };
if likely(upcoming_code_unit < composition_passthrough_bound) {
// No need for surrogate or U+FFFD check, because
// `composition_passthrough_bound` cannot be higher than
// U+0300.
// Fast-track succeeded!
continue 'fast;
}
if unlikely(in_inclusive_range16(upcoming_code_unit, 0x2013, 0x2022)) && upcoming_code_unit != 0x2017 {
// Don't allow dashes and smart quotes to fall off the trie-bypass
// path.
// Fast-track succeeded!
continue 'fast;
}
// This is intentionally bimodal so that if we exit the above trie-bypass path,
// we stay on the trie-reading path until we've processed a non-BMP character
// (likely emoji) or to the end of this passthrough run. This makes NFC faster
// than ICU4C for most real-world content. The result is not optimal for NFKC
// Latin, but let's take the NFC non-Latin win.
let mut trie_value;
let mut upcoming32; // May be surrogate
loop {
// We might be doing a trie lookup by surrogate. Surrogates get
// a decomposition to U+FFFD.
trie_value = composition.decomposition.delegate.trie().bmp(upcoming_code_unit);
if likely(potential_passthrough_and_cannot_combine_backwards(trie_value)) {
// Can't combine backwards, hence a plain (non-backwards-combining)
// starter albeit past `composition_passthrough_bound`
// Fast-track succeeded!
// Instead of going back to `'fast`, we stay here to skip the branch
// for `composition_passthrough_bound`.
if likely(ptr != end) {
// SAFETY: We just checked that `ptr` has not reached `end`.
// `ptr` always advances by one, and we always have a check
// per advancement.
upcoming_code_unit = unsafe { *ptr };
// SAFETY: Since `ptr` hadn't reached `end`, yet, advancing
// by one points to the same allocation or to immediately
// after, which is OK.
ptr = unsafe { ptr.add(1) };
continue;
}
break 'end;
}
upcoming32 = u32::from(upcoming_code_unit);
break;
}
// We might now be looking at a surrogate.
// The loop is only broken out of as goto forward
#[expect(clippy::never_loop)]
'surrogateloop: loop {
// The `likely` annotations _below_ exist to make the code _above_
// go faster!
let surrogate_base = upcoming32.wrapping_sub(0xD800);
if likely(surrogate_base > (0xDFFF - 0xD800)) {
// Not surrogate
break 'surrogateloop;
}
if likely(surrogate_base <= (0xDBFF - 0xD800)) {
// let iter_backup = code_unit_iter.clone();
// if let Some(&low) = code_unit_iter.next() {
if likely(ptr != end) {
// SAFETY: We just checked that `ptr` has not reached `end`.
// `ptr` always advances by one, and we always have a check
// per advancement.
let low = unsafe { *ptr };
if likely(in_inclusive_range16(low, 0xDC00, 0xDFFF)) {
// SAFETY: Since `ptr` hadn't reached `end`, yet, advancing
// by one points to the same allocation or to immediately
// after, which is OK.
ptr = unsafe { ptr.add(1) };
upcoming32 = (upcoming32 << 10) + u32::from(low)
- (((0xD800u32 << 10) - 0x10000u32) + 0xDC00u32);
// Successfully-paired surrogate. Read from the trie again.
trie_value = {
// Semantically, this bit of conditional compilation makes no sense.
// The purpose is to keep LLVM seeing the untyped trie case the way
// it did before so as not to regress the performance of the untyped
// case due to unintuitive optimizer effects. If you care about the
// perf of the untyped trie case and have better ideas, please try
// something better.
#[cfg(feature = "serde")]
{composition.decomposition.delegate.trie().code_point(upcoming32)}
#[cfg(not(feature = "serde"))]
{composition.decomposition.delegate.trie().supplementary(upcoming32)}
};
if likely(potential_passthrough_and_cannot_combine_backwards(trie_value)) {
// Fast-track succeeded!
continue 'fast;
}
break 'surrogateloop;
// } else {
// code_unit_iter = iter_backup;
}
}
}
// unpaired surrogate
upcoming32 = 0xFFFD; // Safe value for `char::from_u32_unchecked` and matches later potential error check.
// trie_value already holds a decomposition to U+FFFD.
debug_assert_eq!(trie_value, NON_ROUND_TRIP_MARKER | BACKWARD_COMBINING_MARKER | 0xFFFD);
break 'surrogateloop;
}
// SAFETY: upcoming32 can no longer be a surrogate.
let upcoming = unsafe { char::from_u32_unchecked(upcoming32) };
let upcoming_with_trie_value = CharacterAndTrieValue::new(upcoming, trie_value);
// We need to fall off the fast path.
composition.decomposition.pending = Some(upcoming_with_trie_value);
let Some(consumed_so_far_slice) = pending_slice.get(..pending_slice.len() -
// code_unit_iter.as_slice().len()
// SAFETY: `ptr` and `end` have been derived from the same allocation
// and `ptr` is never greater than `end`.
unsafe { end.offset_from(ptr) as usize }
- upcoming.len_utf16()) else {
// If we ever come here, it's a bug, but let's avoid panic code paths in release builds.
debug_assert!(false);
// Throw away the results of the fast path.
break 'fastwrap;
};
let mut consumed_so_far = consumed_so_far_slice.chars_with_trie(composition.decomposition.delegate.trie());
// Whether we could do something better than `next_back()` below is
let Some((c_from_back, trie_val_from_back)) = consumed_so_far.next_back() else {
// If we ever come here, it's a bug, but let's avoid panic code paths in release builds.
debug_assert!(false);
// Throw away the results of the fast path.
break 'fastwrap;
};
// TODO: If the previous character was below the passthrough bound,
// we really need to read from the trie. Otherwise, we could maintain
// the most-recent trie value. Need to measure what's more expensive:
// Remembering the trie value on each iteration or re-reading the
// last one after the fast-track run.
undecomposed_starter = CharacterAndTrieValue::new(c_from_back, trie_val_from_back);
sink.write_slice(consumed_so_far.as_slice())?;
break 'fast;
}
break;
}
// End of stream
sink.write_slice(pending_slice)?;
return Ok(());
}
// Sync the main iterator
// composition.decomposition.delegate = code_unit_iter.as_slice().chars();
// SAFETY: `ptr` and `end` have been derive from the same allocation
// and `ptr` is never greater than `end`.
composition.decomposition.delegate = unsafe { core::slice::from_raw_parts(ptr, end.offset_from(ptr) as usize) }.chars_with_trie(composition.decomposition.delegate.trie());
break 'fastwrap;
}
},
text,
sink,
composition,
undecomposed_starter,
pending_slice,
len_utf16,
self,
chars_with_trie,
);
}
/// A normalizer for performing composing normalization.
#[derive(Debug)]
pub struct ComposingNormalizer {
decomposing_normalizer: DecomposingNormalizer,
canonical_compositions: CanonicalCompositionsPayload,
}
impl ComposingNormalizer {
/// Constructs a borrowed version of this type for more efficient querying.
pub fn as_borrowed(&self) -> ComposingNormalizerBorrowed<'_> {
ComposingNormalizerBorrowed {
decomposing_normalizer: self.decomposing_normalizer.as_borrowed(),
canonical_compositions: self.canonical_compositions.as_borrowed(),
}
}
/// NFC constructor using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new_nfc() -> ComposingNormalizerBorrowed<'static> {
ComposingNormalizerBorrowed::new_nfc()
}
icu_provider::gen_buffer_data_constructors!(
() -> error: DataError,
functions: [
new_nfc: skip,
try_new_nfc_with_buffer_provider,
try_new_nfc_unstable,
Self,
]
);
#[doc = icu_provider::gen_buffer_unstable_docs!(UNSTABLE, Self::new_nfc)]
pub fn try_new_nfc_unstable<D>(provider: &D) -> Result<Self, DataError>
where
D: DataProvider<NormalizerNfdDataV1>
+ DataProvider<NormalizerNfdTablesV1>
+ DataProvider<NormalizerNfcV2>
+ ?Sized,
{
let decomposing_normalizer = DecomposingNormalizer::try_new_nfd_unstable(provider)?;
let canonical_compositions: DataPayload<NormalizerNfcV2> =
provider.load(Default::default())?.payload;
Ok(ComposingNormalizer {
decomposing_normalizer,
canonical_compositions: CanonicalCompositionsPayload::Current(canonical_compositions),
})
}
/// NFKC constructor using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [📚 Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new_nfkc() -> ComposingNormalizerBorrowed<'static> {
ComposingNormalizerBorrowed::new_nfkc()
}
icu_provider::gen_buffer_data_constructors!(
() -> error: DataError,
functions: [
new_nfkc: skip,
try_new_nfkc_with_buffer_provider,
try_new_nfkc_unstable,
Self,
]
);
#[doc = icu_provider::gen_buffer_unstable_docs!(UNSTABLE, Self::new_nfkc)]
pub fn try_new_nfkc_unstable<D>(provider: &D) -> Result<Self, DataError>
where
D: DataProvider<NormalizerNfkdDataV1>
+ DataProvider<NormalizerNfdTablesV1>
+ DataProvider<NormalizerNfkdTablesV1>
+ DataProvider<NormalizerNfcV2>
+ ?Sized,
{
let decomposing_normalizer = DecomposingNormalizer::try_new_nfkd_unstable(provider)?;
let canonical_compositions: DataPayload<NormalizerNfcV2> =
provider.load(Default::default())?.payload;
Ok(ComposingNormalizer {
decomposing_normalizer,
canonical_compositions: CanonicalCompositionsPayload::Current(canonical_compositions),
})
}
#[doc = icu_provider::gen_buffer_unstable_docs!(UNSTABLE, Self::new_uts46)]
pub(crate) fn try_new_uts46_unstable<D>(provider: &D) -> Result<Self, DataError>
where
D: DataProvider<NormalizerUts46DataV1>
+ DataProvider<NormalizerNfdTablesV1>
+ DataProvider<NormalizerNfkdTablesV1>
// UTS 46 tables merged into CompatibilityDecompositionTablesV1
+ DataProvider<NormalizerNfcV2>
+ ?Sized,
{
let decomposing_normalizer =
DecomposingNormalizer::try_new_uts46_decomposed_unstable(provider)?;
let canonical_compositions: DataPayload<NormalizerNfcV2> =
provider.load(Default::default())?.payload;
Ok(ComposingNormalizer {
decomposing_normalizer,
canonical_compositions: CanonicalCompositionsPayload::Current(canonical_compositions),
})
}
}
#[cfg(feature = "utf16_iter")]
struct IsNormalizedSinkUtf16<'a> {
expect: &'a [u16],
}
#[cfg(feature = "utf16_iter")]
impl<'a> IsNormalizedSinkUtf16<'a> {
pub fn new(slice: &'a [u16]) -> Self {
IsNormalizedSinkUtf16 { expect: slice }
}
pub fn remaining_len(&self) -> usize {
self.expect.len()
}
}
#[cfg(feature = "utf16_iter")]
impl write16::Write16 for IsNormalizedSinkUtf16<'_> {
fn write_slice(&mut self, s: &[u16]) -> core::fmt::Result {
// We know that if we get a slice, it's a pass-through,
// so we can compare addresses. Indexing is OK, because
// an indexing failure would be a code bug rather than
// an input or data issue.
#[expect(clippy::indexing_slicing)]
if core::ptr::eq(s.as_ptr(), self.expect.as_ptr()) {
self.expect = &self.expect[s.len()..];
Ok(())
} else {
Err(core::fmt::Error {})
}
}
fn write_char(&mut self, c: char) -> core::fmt::Result {
let mut iter = utf16_iter::ErrorReportingUtf16Chars::new(self.expect);
if iter.next() == Some(Ok(c)) {
self.expect = iter.as_slice();
Ok(())
} else {
Err(core::fmt::Error {})
}
}
}
#[cfg(feature = "utf8_iter")]
struct IsNormalizedSinkUtf8<'a> {
expect: &'a [u8],
}
#[cfg(feature = "utf8_iter")]
impl<'a> IsNormalizedSinkUtf8<'a> {
pub fn new(slice: &'a [u8]) -> Self {
IsNormalizedSinkUtf8 { expect: slice }
}
pub fn remaining_len(&self) -> usize {
self.expect.len()
}
}
#[cfg(feature = "utf8_iter")]
impl core::fmt::Write for IsNormalizedSinkUtf8<'_> {
fn write_str(&mut self, s: &str) -> core::fmt::Result {
// We know that if we get a slice, it's a pass-through,
// so we can compare addresses. Indexing is OK, because
// an indexing failure would be a code bug rather than
// an input or data issue.
#[expect(clippy::indexing_slicing)]
if core::ptr::eq(s.as_ptr(), self.expect.as_ptr()) {
self.expect = &self.expect[s.len()..];
Ok(())
} else {
Err(core::fmt::Error {})
}
}
fn write_char(&mut self, c: char) -> core::fmt::Result {
let mut iter = utf8_iter::ErrorReportingUtf8Chars::new(self.expect);
if iter.next() == Some(Ok(c)) {
self.expect = iter.as_slice();
Ok(())
} else {
Err(core::fmt::Error {})
}
}
}
struct IsNormalizedSinkStr<'a> {
expect: &'a str,
}
impl<'a> IsNormalizedSinkStr<'a> {
pub fn new(slice: &'a str) -> Self {
IsNormalizedSinkStr { expect: slice }
}
pub fn remaining_len(&self) -> usize {
self.expect.len()
}
}
impl core::fmt::Write for IsNormalizedSinkStr<'_> {
fn write_str(&mut self, s: &str) -> core::fmt::Result {
// We know that if we get a slice, it's a pass-through,
// so we can compare addresses. Indexing is OK, because
// an indexing failure would be a code bug rather than
// an input or data issue.
if core::ptr::eq(s.as_ptr(), self.expect.as_ptr()) {
self.expect = &self.expect[s.len()..];
Ok(())
} else {
Err(core::fmt::Error {})
}
}
fn write_char(&mut self, c: char) -> core::fmt::Result {
let mut iter = self.expect.chars();
if iter.next() == Some(c) {
self.expect = iter.as_str();
Ok(())
} else {
Err(core::fmt::Error {})
}
}
}