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// devela::text::char::iter::str
use crate::{Char, CharIter, char7, char8, char16, charu, is, slice};
/// Methods available when constructed from a string slice.
impl<'a> CharIter<'a, &str> {
/* constructors */
/// Returns a new iterator over the Unicode scalars of a `string` slice.
#[inline(always)] #[rustfmt::skip]
pub const fn new(string: &'a str) -> Self {
Self::_new(string.as_bytes(), 0)
}
/// Returns a new iterator over the Unicode scalars of a `string` slice,
/// starting at `index`.
///
/// Returns `None` if the given index is not a valid character boundary.
#[must_use] #[inline(always)] #[rustfmt::skip]
pub const fn new_at(string: &'a str, index: usize) -> Option<Self> {
if string.is_char_boundary(index) {
Some(Self::_new(string.as_bytes(), index))
} else {
None
}
}
/* misc. */
/// Returns the total number of Unicode scalars, consuming the iterator.
pub const fn count(mut self) -> usize {
let mut counter = 0;
while self.pos < self.bytes.len() {
let (_, len) = Char(self.bytes).to_scalar_unchecked(self.pos);
self.pos += len;
counter += 1;
}
counter
}
/* next_char* methods */
/// Returns the next Unicode scalar.
///
/// Returns `None` once there are no more characters left.
///
/// # Example
/// ```
/// # use devela::CharIter;
/// let input = "CЀ𐌅G";
/// let mut iter = CharIter::<&str>::new(input);
/// assert_eq![iter.next_char().unwrap(), 'C']; // Basic Latin
/// assert_eq![iter.next_char().unwrap(), 'Ð']; // Latin-1 supplement
/// assert_eq![iter.next_char().unwrap(), '€']; // Basic Multilingual plane
/// assert_eq![iter.next_char().unwrap(), '𐌅']; // Supplementary Multilingual Plane
/// assert_eq![iter.next_char().unwrap(), 'G']; // Basic Latin
/// assert![iter.next_char().is_none()];
/// ```
/// # Features
/// Uses the `unsafe_str` feature to skip validation checks.
#[must_use] #[rustfmt::skip]
pub const fn next_char(&mut self) -> Option<char> {
is![self.pos >= self.bytes.len(), return None];
let (cp, len) = Char(self.bytes).to_scalar_unchecked(self.pos);
let ch = {
#[cfg(any(feature = "safe_text", not(feature = "unsafe_str")))]
{ crate::unwrap![some? char::from_u32(cp)] }
#[cfg(all(not(feature = "safe_text"), feature = "unsafe_str"))]
unsafe { char::from_u32_unchecked(cp) }
};
self.pos += len;
Some(ch)
}
/// Returns the next 7-bit Unicode scalar.
///
/// Returns `None` once there are no more characters left,
/// or if the next character is not ASCII.
///
/// # Example
/// ```
/// # use devela::CharIter;
/// let input = "CЀ𐌅G";
/// let mut iter = CharIter::<&str>::new(input);
/// assert_eq![iter.next_char7().unwrap(), "C"]; // Basic Latin
/// assert![iter.next_char7().is_none()];
/// ```
/// # Features
/// Uses the `unsafe_niche` feature to skip validation checks.
#[must_use]
pub const fn next_char7(&mut self) -> Option<char7> {
is![self.pos >= self.bytes.len(), return None];
let byte = self.bytes[self.pos];
is![
byte.is_ascii(),
{
self.pos += 1;
Some(char7::new_unchecked(byte))
},
None
]
}
/// Returns the next 8-bit Unicode scalar.
///
/// Returns `None` once there are no more characters left,
/// or if the next character can't fit in 1 byte.
///
/// # Example
/// ```
/// # use devela::CharIter;
/// let input = "CЀ𐌅G";
/// let mut iter = CharIter::<&str>::new(input);
/// assert_eq![iter.next_char8().unwrap(), "C"]; // Basic Latin
/// assert_eq![iter.next_char8().unwrap(), "Ð"]; // Latin-1 supplement
/// assert![iter.next_char8().is_none()];
/// ```
#[must_use]
pub const fn next_char8(&mut self) -> Option<char8> {
is![self.pos >= self.bytes.len(), return None];
let (cp, len) = Char(self.bytes).to_scalar_unchecked(self.pos);
if Char(cp).len_bytes() == 1 {
self.pos += len;
Some(char8(cp as u8))
} else {
None
}
}
/// Returns the next 16-bit Unicode scalar.
///
/// Returns `None` once there are no more characters left,
/// or if the next character can't fit in 2 bytes.
///
/// # Example
/// ```
/// # use devela::CharIter;
/// let input = "CЀ𐌅G";
/// let mut iter = CharIter::<&str>::new(input);
/// assert_eq![iter.next_char16().unwrap(), "C"]; // Basic Latin
/// assert_eq![iter.next_char16().unwrap(), "Ð"]; // Latin-1 supplement
/// assert_eq![iter.next_char16().unwrap(), "€"]; // Basic Multilingual plane
/// assert![iter.next_char16().is_none()];
/// ```
/// # Features
/// Uses the `unsafe_niche` feature to skip validation checks.
#[must_use]
pub const fn next_char16(&mut self) -> Option<char16> {
is![self.pos >= self.bytes.len(), return None];
let (cp, len) = Char(self.bytes).to_scalar_unchecked(self.pos);
if Char(cp).len_bytes() <= 2 {
self.pos += len;
Some(char16::new_unchecked(cp as u16))
} else {
None
}
}
/// Returns the next Unicode scalar using a UTF-8 representation.
///
/// Returns `None` once there are no more characters left.
///
/// # Example
/// ```
/// # use devela::CharIter;
/// let input = "CЀ𐌅G";
/// let mut iter = CharIter::<&str>::new(input);
/// assert_eq![iter.next_charu().unwrap(), "C"]; // Basic Latin
/// assert_eq![iter.next_charu().unwrap(), "Ð"]; // Latin-1 supplement
/// assert_eq![iter.next_charu().unwrap(), "€"]; // Basic Multilingual plane
/// assert_eq![iter.next_charu().unwrap(), "𐌅"]; // Supplementary Multilingual Plane
/// assert_eq![iter.next_charu().unwrap(), "G"]; // Basic Latin
/// assert![iter.next_charu().is_none()];
/// ```
/// # Features
/// Uses the `unsafe_hint` feature to optimize out unreachable branches.
#[must_use] #[rustfmt::skip]
pub const fn next_charu(&mut self) -> Option<charu> {
is![self.pos >= self.bytes.len(), return None];
let len = Char(self.bytes[self.pos]).len_utf8_unchecked();
let ch = charu::decode_utf8(slice![self.bytes, self.pos,..], len);
self.pos += len;
Some(ch)
}
/* next_scalar* methods */
/// Returns the next Unicode scalar value.
///
/// This is implemented via `Char::`[`to_scalar_unchecked`][Char::to_scalar_unchecked].
///
/// Returns `None` once there are no more characters left.
#[must_use] #[rustfmt::skip]
pub const fn next_scalar(&mut self) -> Option<u32> {
is![self.pos >= self.bytes.len(), return None];
let (cp, len) = Char(self.bytes).to_scalar_unchecked(self.pos);
self.pos += len;
Some(cp)
}
/* find_* methods */
/// Finds the next 7-bit ASCII character, skipping any non-ASCII bytes.
///
/// Continues searching through the input until an ASCII character is found
/// or the end is reached. Never returns `None` until the entire input is exhausted.
///
/// # Example
/// ```
/// # use devela::CharIter;
/// let input = "CЀ𐌅G";
/// let mut iter = CharIter::<&str>::new(input);
/// assert_eq![iter.find_char7().unwrap(), "C"]; // Basic Latin
/// assert_eq![iter.find_char7().unwrap(), "G"]; // Basic Latin
/// ```
/// # Features
/// Uses the `unsafe_niche` feature to skip validation checks.
#[must_use]
pub const fn find_char7(&mut self) -> Option<char7> {
while self.pos < self.bytes.len() {
let (cp, len) = Char(self.bytes).to_scalar_unchecked(self.pos);
self.pos += len;
is![Char(cp).is_ascii(), return Some(char7::new_unchecked(cp as u8))];
}
None
}
/// Finds the next Unicode scalar that fits in 8 bits, skipping larger scalars.
///
/// Continues searching through the input until a scalar value ≤ 255 is found
/// or the end is reached. Never returns `None` until the entire input is exhausted.
///
/// # Example
/// ```
/// # use devela::CharIter;
/// let input = "CЀ𐌅G";
/// let mut iter = CharIter::<&str>::new(input);
/// assert_eq![iter.find_char8().unwrap(), "C"]; // Basic Latin
/// assert_eq![iter.find_char8().unwrap(), "Ð"]; // Latin-1 supplement
/// assert_eq![iter.find_char8().unwrap(), "G"]; // Basic Latin
/// assert![iter.find_char8().is_none()];
/// ```
#[must_use]
pub const fn find_char8(&mut self) -> Option<char8> {
while self.pos < self.bytes.len() {
let (cp, len) = Char(self.bytes).to_scalar_unchecked(self.pos);
self.pos += len;
is![Char(cp).len_bytes() == 1, return Some(char8(cp as u8))];
}
None
}
/// Finds the next Unicode scalar that fits in 16 bits, skipping larger scalars.
///
/// Continues searching through the input until a scalar value ≤ 65535 is found
/// or the end is reached. Never returns `None` until the entire input is exhausted.
///
/// # Example
/// ```
/// # use devela::CharIter;
/// let input = "CЀ𐌅G";
/// let mut iter = CharIter::<&str>::new(input);
/// assert_eq![iter.find_char16().unwrap(), "C"]; // Basic Latin
/// assert_eq![iter.find_char16().unwrap(), "Ð"]; // Latin-1 supplement
/// assert_eq![iter.find_char16().unwrap(), "€"]; // Basic Multilingual plane
/// assert_eq![iter.find_char16().unwrap(), "G"]; // Basic Latin
/// assert![iter.find_char16().is_none()];
/// ```
/// # Features
/// Uses the `unsafe_niche` feature to skip validation checks.
#[must_use]
pub const fn find_char16(&mut self) -> Option<char16> {
while self.pos < self.bytes.len() {
let (cp, len) = Char(self.bytes).to_scalar_unchecked(self.pos);
self.pos += len;
is![Char(cp).len_bytes() <= 2, return Some(char16::new_unchecked(cp as u16))];
}
None
}
}