mozilla-central/third_party/rust/icu_normalizer/src/properties.rs

Source code

Revision control

Copy as Markdown

Other Tools

// 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
//! Access to the Unicode properties or property-based operations that
//! are required for NFC and NFD.
//!
//! Applications should generally use the full normalizers that are
//! provided at the top level of this crate. However, the APIs in this
//! module are provided for callers such as HarfBuzz that specifically
//! want access to the raw canonical composition operation e.g. for use in a
//! glyph-availability-guided custom normalizer.
use crate::char_from_u16;
use crate::error::NormalizerError;
use crate::in_inclusive_range;
use crate::provider::CanonicalCompositionsV1Marker;
use crate::provider::CanonicalDecompositionDataV1Marker;
use crate::provider::CanonicalDecompositionTablesV1Marker;
use crate::provider::NonRecursiveDecompositionSupplementV1Marker;
use crate::trie_value_has_ccc;
use crate::trie_value_indicates_special_non_starter_decomposition;
use crate::BACKWARD_COMBINING_STARTER_MARKER;
use crate::FDFA_MARKER;
use crate::HANGUL_L_BASE;
use crate::HANGUL_N_COUNT;
use crate::HANGUL_S_BASE;
use crate::HANGUL_S_COUNT;
use crate::HANGUL_T_BASE;
use crate::HANGUL_T_COUNT;
use crate::HANGUL_V_BASE;
use crate::NON_ROUND_TRIP_MARKER;
use crate::SPECIAL_NON_STARTER_DECOMPOSITION_MARKER_U16;
/// want access to the underlying properties e.g. for use in a
/// glyph-availability-guided custom normalizer.
use icu_properties::CanonicalCombiningClass;
use icu_provider::prelude::*;
/// The raw canonical composition operation.
///
/// Callers should generally use `ComposingNormalizer` instead of this API.
/// However, this API is provided for callers such as HarfBuzz that specifically
/// want access to the raw canonical composition operation e.g. for use in a
/// glyph-availability-guided custom normalizer.
#[derive(Debug)]
pub struct CanonicalComposition {
canonical_compositions: DataPayload<CanonicalCompositionsV1Marker>,
}
#[cfg(feature = "compiled_data")]
impl Default for CanonicalComposition {
fn default() -> Self {
Self::new()
}
}
impl CanonicalComposition {
/// 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.
///
/// # Examples
///
/// ```
/// let comp = icu::normalizer::properties::CanonicalComposition::new();
///
/// assert_eq!(comp.compose('a', 'b'), None); // Just two non-composing starters
/// assert_eq!(comp.compose('a', '\u{0308}'), Some('Γ€'));
/// assert_eq!(comp.compose('αΊΉ', '\u{0302}'), Some('ệ'));
/// assert_eq!(comp.compose('𝅗', 'π…₯'), None); // Composition exclusion
/// assert_eq!(comp.compose('ে', 'ΰ¦Ύ'), Some('ো')); // Second is starter
/// assert_eq!(comp.compose('α„€', 'α…‘'), Some('κ°€')); // Hangul LV
/// assert_eq!(comp.compose('κ°€', 'ᆨ'), Some('각')); // Hangul LVT
/// ```
#[inline(always)]
pub fn compose(&self, starter: char, second: char) -> Option<char> {
crate::compose(
self.canonical_compositions
.get()
.canonical_compositions
.iter(),
starter,
second,
)
}
/// Constructs a new `CanonicalComposition` using compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [πŸ“š Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new() -> Self {
Self {
canonical_compositions: DataPayload::from_static_ref(
crate::provider::Baked::SINGLETON_NORMALIZER_COMP_V1,
),
}
}
icu_provider::gen_any_buffer_data_constructors!(locale: skip, options: skip, error: NormalizerError,
#[cfg(skip)]
functions: [
new,
try_new_with_any_provider,
try_new_with_buffer_provider,
try_new_unstable,
Self,
]
);
#[doc = icu_provider::gen_any_buffer_unstable_docs!(UNSTABLE, Self::new)]
pub fn try_new_unstable<D>(provider: &D) -> Result<Self, NormalizerError>
where
D: DataProvider<CanonicalCompositionsV1Marker> + ?Sized,
{
let canonical_compositions: DataPayload<CanonicalCompositionsV1Marker> =
provider.load(Default::default())?.take_payload()?;
Ok(CanonicalComposition {
canonical_compositions,
})
}
}
/// The outcome of non-recursive canonical decomposition of a character.
#[allow(clippy::exhaustive_enums)]
#[derive(Debug, PartialEq, Eq)]
pub enum Decomposed {
/// The character is its own canonical decomposition.
Default,
/// The character decomposes to a single different character.
Singleton(char),
/// The character decomposes to two characters.
Expansion(char, char),
}
/// The raw (non-recursive) canonical decomposition operation.
///
/// Callers should generally use `DecomposingNormalizer` instead of this API.
/// However, this API is provided for callers such as HarfBuzz that specifically
/// want access to non-recursive canonical decomposition e.g. for use in a
/// glyph-availability-guided custom normalizer.
#[derive(Debug)]
pub struct CanonicalDecomposition {
decompositions: DataPayload<CanonicalDecompositionDataV1Marker>,
tables: DataPayload<CanonicalDecompositionTablesV1Marker>,
non_recursive: DataPayload<NonRecursiveDecompositionSupplementV1Marker>,
}
#[cfg(feature = "compiled_data")]
impl Default for CanonicalDecomposition {
fn default() -> Self {
Self::new()
}
}
impl CanonicalDecomposition {
/// Performs non-recursive canonical decomposition (including for Hangul).
///
/// ```
/// use icu::normalizer::properties::Decomposed;
/// let decomp = icu::normalizer::properties::CanonicalDecomposition::new();
///
/// assert_eq!(decomp.decompose('e'), Decomposed::Default);
/// assert_eq!(
/// decomp.decompose('ệ'),
/// Decomposed::Expansion('αΊΉ', '\u{0302}')
/// );
/// assert_eq!(decomp.decompose('각'), Decomposed::Expansion('κ°€', 'ᆨ'));
/// assert_eq!(decomp.decompose('\u{212B}'), Decomposed::Singleton('Γ…')); // ANGSTROM SIGN
/// assert_eq!(decomp.decompose('\u{2126}'), Decomposed::Singleton('Ξ©')); // OHM SIGN
/// assert_eq!(decomp.decompose('\u{1F71}'), Decomposed::Singleton('Ξ¬')); // oxia
/// ```
#[inline]
pub fn decompose(&self, c: char) -> Decomposed {
let lvt = u32::from(c).wrapping_sub(HANGUL_S_BASE);
if lvt >= HANGUL_S_COUNT {
return self.decompose_non_hangul(c);
}
let t = lvt % HANGUL_T_COUNT;
if t == 0 {
let l = lvt / HANGUL_N_COUNT;
let v = (lvt % HANGUL_N_COUNT) / HANGUL_T_COUNT;
// Safe because values known to be in range
return Decomposed::Expansion(
unsafe { char::from_u32_unchecked(HANGUL_L_BASE + l) },
unsafe { char::from_u32_unchecked(HANGUL_V_BASE + v) },
);
}
let lv = lvt - t;
// Safe because values known to be in range
Decomposed::Expansion(
unsafe { char::from_u32_unchecked(HANGUL_S_BASE + lv) },
unsafe { char::from_u32_unchecked(HANGUL_T_BASE + t) },
)
}
/// Performs non-recursive canonical decomposition except Hangul syllables
/// are reported as `Decomposed::Default`.
#[inline(always)]
fn decompose_non_hangul(&self, c: char) -> Decomposed {
let decomposition = self.decompositions.get().trie.get(c);
if decomposition <= BACKWARD_COMBINING_STARTER_MARKER {
return Decomposed::Default;
}
// The loop is only broken out of as goto forward
#[allow(clippy::never_loop)]
loop {
let trail_or_complex = (decomposition >> 16) as u16;
let lead = decomposition as u16;
if lead > NON_ROUND_TRIP_MARKER && trail_or_complex != 0 {
// Decomposition into two BMP characters: starter and non-starter
if in_inclusive_range(c, '\u{1F71}', '\u{1FFB}') {
// Look in the other trie due to oxia singleton
// mappings to corresponding character with tonos.
break;
}
return Decomposed::Expansion(char_from_u16(lead), char_from_u16(trail_or_complex));
}
if lead > NON_ROUND_TRIP_MARKER {
// Decomposition into one BMP character or non-starter
debug_assert_ne!(
lead, FDFA_MARKER,
"How come we got the U+FDFA NFKD marker here?"
);
if lead == SPECIAL_NON_STARTER_DECOMPOSITION_MARKER_U16 {
// Non-starter
if !in_inclusive_range(c, '\u{0340}', '\u{0F81}') {
return Decomposed::Default;
}
return match c {
'\u{0340}' => {
// COMBINING GRAVE TONE MARK
Decomposed::Singleton('\u{0300}')
}
'\u{0341}' => {
// COMBINING ACUTE TONE MARK
Decomposed::Singleton('\u{0301}')
}
'\u{0343}' => {
// COMBINING GREEK KORONIS
Decomposed::Singleton('\u{0313}')
}
'\u{0344}' => {
// COMBINING GREEK DIALYTIKA TONOS
Decomposed::Expansion('\u{0308}', '\u{0301}')
}
'\u{0F73}' => {
// TIBETAN VOWEL SIGN II
Decomposed::Expansion('\u{0F71}', '\u{0F72}')
}
'\u{0F75}' => {
// TIBETAN VOWEL SIGN UU
Decomposed::Expansion('\u{0F71}', '\u{0F74}')
}
'\u{0F81}' => {
// TIBETAN VOWEL SIGN REVERSED II
Decomposed::Expansion('\u{0F71}', '\u{0F80}')
}
_ => Decomposed::Default,
};
}
return Decomposed::Singleton(char_from_u16(lead));
}
// The recursive decomposition of ANGSTROM SIGN is in the complex
// decomposition structure to avoid a branch in `potential_passthrough`
// for the BMP case.
if c == '\u{212B}' {
// ANGSTROM SIGN
return Decomposed::Singleton('\u{00C5}');
}
// Complex decomposition
// Format for 16-bit value:
// 15..13: length minus two for 16-bit case and length minus one for
// the 32-bit case. Length 8 needs to fit in three bits in
// the 16-bit case, and this way the value is future-proofed
// up to 9 in the 16-bit case. Zero is unused and length one
// in the 16-bit case goes directly into the trie.
// 12: 1 if all trailing characters are guaranteed non-starters,
// 0 if no guarantees about non-starterness.
// Note: The bit choice is this way around to allow for
// dynamically falling back to not having this but instead
// having one more bit for length by merely choosing
// different masks.
// 11..0: Start offset in storage. The offset is to the logical
// sequence of scalars16, scalars32, supplementary_scalars16,
// supplementary_scalars32.
let offset = usize::from(trail_or_complex & 0xFFF);
let tables = self.tables.get();
if offset < tables.scalars16.len() {
if usize::from(trail_or_complex >> 13) != 0 {
// i.e. logical len isn't 2
break;
}
if let Some(first) = tables.scalars16.get(offset) {
if let Some(second) = tables.scalars16.get(offset + 1) {
// Two BMP starters
return Decomposed::Expansion(char_from_u16(first), char_from_u16(second));
}
}
// GIGO case
debug_assert!(false);
return Decomposed::Default;
}
let len = usize::from(trail_or_complex >> 13) + 1;
if len > 2 {
break;
}
let offset24 = offset - tables.scalars16.len();
if let Some(first_c) = tables.scalars24.get(offset24) {
if len == 1 {
if c != first_c {
return Decomposed::Singleton(first_c);
} else {
// Singleton representation used to avoid
// NFC passthrough of characters that combine
// with starters that can occur as the first
// character of an expansion decomposition.
// See section 5 of
return Decomposed::Default;
}
}
if let Some(second_c) = tables.scalars24.get(offset24 + 1) {
return Decomposed::Expansion(first_c, second_c);
}
}
// GIGO case
debug_assert!(false);
return Decomposed::Default;
}
let non_recursive = self.non_recursive.get();
let non_recursive_decomposition = non_recursive.trie.get(c);
if non_recursive_decomposition == 0 {
// GIGO case
debug_assert!(false);
return Decomposed::Default;
}
let trail_or_complex = (non_recursive_decomposition >> 16) as u16;
let lead = non_recursive_decomposition as u16;
if lead != 0 && trail_or_complex != 0 {
// Decomposition into two BMP characters
return Decomposed::Expansion(char_from_u16(lead), char_from_u16(trail_or_complex));
}
if lead != 0 {
// Decomposition into one BMP character
return Decomposed::Singleton(char_from_u16(lead));
}
// Decomposition into two non-BMP characters
// Low is offset into a table plus one to keep it non-zero.
let offset = usize::from(trail_or_complex - 1);
if let Some(first) = non_recursive.scalars24.get(offset) {
if let Some(second) = non_recursive.scalars24.get(offset + 1) {
return Decomposed::Expansion(first, second);
}
}
// GIGO case
debug_assert!(false);
Decomposed::Default
}
/// Construct from compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [πŸ“š Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new() -> Self {
const _: () = assert!(
crate::provider::Baked::SINGLETON_NORMALIZER_NFDEX_V1
.scalars16
.const_len()
+ crate::provider::Baked::SINGLETON_NORMALIZER_NFDEX_V1
.scalars24
.const_len()
<= 0xFFF,
"NormalizerError::FutureExtension"
);
Self {
decompositions: DataPayload::from_static_ref(
crate::provider::Baked::SINGLETON_NORMALIZER_NFD_V1,
),
tables: DataPayload::from_static_ref(
crate::provider::Baked::SINGLETON_NORMALIZER_NFDEX_V1,
),
non_recursive: DataPayload::from_static_ref(
crate::provider::Baked::SINGLETON_NORMALIZER_DECOMP_V1,
),
}
}
icu_provider::gen_any_buffer_data_constructors!(locale: skip, options: skip, error: NormalizerError,
#[cfg(skip)]
functions: [
new,
try_new_with_any_provider,
try_new_with_buffer_provider,
try_new_unstable,
Self,
]
);
#[doc = icu_provider::gen_any_buffer_unstable_docs!(UNSTABLE, Self::new)]
pub fn try_new_unstable<D>(provider: &D) -> Result<Self, NormalizerError>
where
D: DataProvider<CanonicalDecompositionDataV1Marker>
+ DataProvider<CanonicalDecompositionTablesV1Marker>
+ DataProvider<NonRecursiveDecompositionSupplementV1Marker>
+ ?Sized,
{
let decompositions: DataPayload<CanonicalDecompositionDataV1Marker> =
provider.load(Default::default())?.take_payload()?;
let tables: DataPayload<CanonicalDecompositionTablesV1Marker> =
provider.load(Default::default())?.take_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(NormalizerError::FutureExtension);
}
let non_recursive: DataPayload<NonRecursiveDecompositionSupplementV1Marker> =
provider.load(Default::default())?.take_payload()?;
Ok(CanonicalDecomposition {
decompositions,
tables,
non_recursive,
})
}
}
/// Lookup of the Canonical_Combining_Class Unicode property.
///
/// # Example
///
/// ```
/// use icu::properties::CanonicalCombiningClass;
/// use icu::normalizer::properties::CanonicalCombiningClassMap;
///
/// let map = CanonicalCombiningClassMap::new();
/// assert_eq!(map.get('a'), CanonicalCombiningClass::NotReordered); // U+0061: LATIN SMALL LETTER A
/// assert_eq!(map.get32(0x0301), CanonicalCombiningClass::Above); // U+0301: COMBINING ACUTE ACCENT
/// ```
#[derive(Debug)]
pub struct CanonicalCombiningClassMap {
/// The data trie
decompositions: DataPayload<CanonicalDecompositionDataV1Marker>,
}
#[cfg(feature = "compiled_data")]
impl Default for CanonicalCombiningClassMap {
fn default() -> Self {
Self::new()
}
}
impl CanonicalCombiningClassMap {
/// Look up the canonical combining class for a scalar value
#[inline(always)]
pub fn get(&self, c: char) -> CanonicalCombiningClass {
self.get32(u32::from(c))
}
/// Look up the canonical combining class for a scalar value
/// represented as `u32`. If the argument is outside the scalar
/// value range, `CanonicalCombiningClass::NotReordered` is returned.
pub fn get32(&self, c: u32) -> CanonicalCombiningClass {
let trie_value = self.decompositions.get().trie.get32(c);
if trie_value_has_ccc(trie_value) {
CanonicalCombiningClass(trie_value as u8)
} else if trie_value_indicates_special_non_starter_decomposition(trie_value) {
match c {
0x0340 | 0x0341 | 0x0343 | 0x0344 => CanonicalCombiningClass::Above,
_ => CanonicalCombiningClass::NotReordered,
}
} else {
CanonicalCombiningClass::NotReordered
}
}
/// Construct from compiled data.
///
/// ✨ *Enabled with the `compiled_data` Cargo feature.*
///
/// [πŸ“š Help choosing a constructor](icu_provider::constructors)
#[cfg(feature = "compiled_data")]
pub const fn new() -> Self {
CanonicalCombiningClassMap {
decompositions: DataPayload::from_static_ref(
crate::provider::Baked::SINGLETON_NORMALIZER_NFD_V1,
),
}
}
icu_provider::gen_any_buffer_data_constructors!(locale: skip, options: skip, error: NormalizerError,
#[cfg(skip)]
functions: [
new,
try_new_with_any_provider,
try_new_with_buffer_provider,
try_new_unstable,
Self,
]);
#[doc = icu_provider::gen_any_buffer_unstable_docs!(UNSTABLE, Self::new)]
pub fn try_new_unstable<D>(provider: &D) -> Result<Self, NormalizerError>
where
D: DataProvider<CanonicalDecompositionDataV1Marker> + ?Sized,
{
let decompositions: DataPayload<CanonicalDecompositionDataV1Marker> =
provider.load(Default::default())?.take_payload()?;
Ok(CanonicalCombiningClassMap { decompositions })
}
}