Struct icu_collections::codepointtrie::cptrie::CodePointTrieHeader

pub struct CodePointTrieHeader {
    pub high_start: u32,
    pub shifted12_high_start: u16,
    pub index3_null_offset: u16,
    pub data_null_offset: u32,
    pub null_value: u32,
    pub trie_type: TrieType,
}

This struct contains the fixed-length header fields of a CodePointTrie.

Fields

high_start: u32

The code point of the start of the last range of the trie. A range is defined as a partition of the code point space such that the value in this trie associated with all code points of the same range is the same.

For the property value data for many Unicode properties, often times, high_start is U+10000 or lower. In such cases, not reserving space in the index array for duplicate values is a large savings. The “highValue” associated with the high_start range is stored at the second-to-last position of the data array. (See impl_const::HIGH_VALUE_NEG_DATA_OFFSET.)

shifted12_high_start: u16

A version of the high_start value that is right-shifted 12 spaces, but is rounded up to a multiple 0x1000 for easy testing from UTF-8 lead bytes.

index3_null_offset: u16

Offset for the null block in the “index-3” table of the index array. Set to an impossibly high value (e.g., 0xffff) if there is no dedicated index-3 null block.

data_null_offset: u32

Internal data null block offset, not shifted. Set to an impossibly high value (e.g., 0xfffff) if there is no dedicated data null block.

null_value: u32

The value stored in the trie that represents a null value being associated to a code point.

trie_type: TrieType

The enum value representing the type of trie, where trie type is as it is defined in ICU (ex: Fast, Small).

Trait Implementations

impl Clone for CodePointTrieHeader

fn clone(&self) -> CodePointTrieHeader

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for CodePointTrieHeader

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for CodePointTrieHeader

fn eq(&self, other: &CodePointTrieHeader) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'a> Yokeable<'a> for CodePointTrieHeader

where Self: Sized,

type Output = CodePointTrieHeader

This type MUST be Self with the 'static replaced with 'a, i.e. Self<'a>

fn transform(&self) -> &Self::Output

This method must cast self between &'a Self<'static> and &'a Self<'a>.

fn transform_owned(self) -> Self::Output

This method must cast self between Self<'static> and Self<'a>.

unsafe fn make(this: Self::Output) -> Self

This method can be used to cast away Self<'a>’s lifetime.

fn transform_mut<F>(&'a mut self, f: F)

where F: 'static + for<'b> FnOnce(&'b mut Self::Output),

This method must cast self between &'a mut Self<'static> and &'a mut Self<'a>, and pass it to f.

impl<'zf> ZeroFrom<'zf, CodePointTrieHeader> for CodePointTrieHeader

fn zero_from(this: &'zf Self) -> Self

Clone the other C into a struct that may retain references into C.

impl Copy for CodePointTrieHeader

impl Eq for CodePointTrieHeader

impl StructuralPartialEq for CodePointTrieHeader