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//! An iterator that skips values equal to a provided value.
//!
//! Iterators over a contiguous slice, returning all values
//! except for those matching the provided skip value.
//!
//! # Complexity
//!
//! Although superficially quite simple, the level of complexity
//! introduced by digit separators can be quite complex, due
//! the number of permutations during parsing.
//!
//! We can consume any combinations of of \[0,3\] items from the following set:
//! - \[l\]eading digit separators, where digit separators occur before
//! digits.
//! - \[i\]nternal digit separators, where digit separators occur between
//! digits.
//! - \[t\]railing digit separators, where digit separators occur after
//! digits.
//!
//! In addition to those combinations, we can also have:
//! - \[c\]onsecutive digit separators, which allows two digit separators to
//! be adjacent.
//!
//! # Shorthand
//!
//! We will use the term consumer to denote a function that consumes digits,
//! splitting an input buffer at an index, where the leading section contains
//! valid input digits, and the trailing section contains invalid characters.
//! Due to the number of combinations for consumers, we use the following
//! shorthand to denote consumers:
//! - `no`, does not use a digit separator.
//! - `l`, consumes leading digit separators.
//! - `i`, consumes internal digit separators.
//! - `t`, consumes trailing digit separators.
//! - `c`, consumes consecutive digit separators.
//!
//! The `next`/`iter` algorithms are therefore named `next_x`, where `x`
//! represents the shorthand name of the consumer, in sorted order.
//! For example, `next_ilt` means that consumer can skip internal,
//! leading, and trailing digit separators, but not consecutive ones.
#![cfg(all(feature = "format", feature = "parse"))]
use core::{mem, ptr};
use crate::digit::char_is_digit_const;
use crate::format::NumberFormat;
use crate::format_flags as flags;
use crate::iterator::{DigitsIter, Iter};
// IS_ILTC
// -------
// NOTE: The compiler optimizes all these methods pretty well: it's as
// efficient or almost as efficient as optimized assembly without unsafe
// code, especially since we have to do bounds checking
// before and the compiler can determine all cases correctly.
/// Helpers to get the next or previous elements for checks.
///
/// This has the non-consecutive iterator variants as well
/// as the consecutive ones. The consecutive ones will iteratively
/// process all digits.
macro_rules! indexing {
(@next $self:ident, $index:expr) => {
$index.wrapping_add(1)
};
(@nextc $self:ident, $index:expr) => {{
let mut index = $index;
let slc = $self.byte.slc;
while slc.get(index.wrapping_add(1)).map_or(false, |&x| $self.is_digit_separator(x)) {
index = index.wrapping_add(1);
}
index.wrapping_add(1)
}};
(@prev $self:ident, $index:expr) => {
$index.wrapping_sub(1)
};
(@prevc $self:ident, $index:expr) => {{
let mut index = $index;
let slc = $self.byte.slc;
while slc.get(index.wrapping_sub(1)).map_or(false, |&x| $self.is_digit_separator(x)) {
index = index.wrapping_sub(1);
}
index.wrapping_sub(1)
}};
}
/// Determine if a single digit separator is internal.
///
/// # Examples
///
/// - `1__1_23`- invalid
/// - `1_1__23`- invalid
/// - `1_1_23`- valid
/// - `11_x23`- invalid
/// - `_1123`- invalid
/// - `+_1123`- invalid
/// - `_+1123`- invalid
/// - `1123_`- invalid
/// - `1123_.`- invalid
/// - `112_3.`- valid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_i {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index - 1` is a digit
// - `index + 1` is a digit
let prev = indexing!(@prev $self, $index);
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(prev).map_or(false, |&x| $self.is_digit(x)) &&
slc.get(next).map_or(false, |&x| $self.is_digit(x))
}};
(@first $self:ident) => {
is_i!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: We must have validated `prev`, so this just checks `next`.
// NOTE: The conditions here then are that:
// - `index + 1` is a digit
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(false, |&x| $self.is_digit(x))
}};
(@internal $self:ident) => {
is_i!(@internal $self, $self.byte.index)
};
}
/// Determine if consecutive digit separators are internal.
///
/// # Examples
///
/// - `1__1_23`- valid
/// - `1_1__23`- valid
/// - `1_1_23`- valid
/// - `11_x23`- invalid
/// - `_1123`- invalid
/// - `+_1123`- invalid
/// - `_+1123`- invalid
/// - `1123_`- invalid
/// - `1123_.`- invalid
/// - `112_3.`- valid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_ic {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index - 1` is a digit after consuming digit separators
// - `index + 1` is a digit after consuming digit separators
let prev = indexing!(@prevc $self, $index);
let next = indexing!(@nextc $self, $index);
let slc = $self.byte.slc;
slc.get(prev).map_or(false, |&x| $self.is_digit(x)) &&
slc.get(next).map_or(false, |&x| $self.is_digit(x))
}};
(@first $self:ident) => {
is_ic!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: We must have validated `prev`, so this just checks `next`.
// NOTE: The conditions here then are that:
// - `index + 1` is a digit after consuming digit separators
let next = indexing!(@nextc $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(false, |&x| $self.is_digit(x))
}};
(@internal $self:ident) => {
is_ic!(@internal $self, $self.byte.index)
};
}
/// Determine if a single digit separator is leading.
///
/// # Examples
///
/// - `__123`- invalid
/// - `+__123`- invalid
/// - `._123`- valid
/// - `_+123`- valid
/// - `_123`- valid
/// - `+_123`- valid
///
/// Having a subsequent sign character is fine since it might
/// be part of a partial parser.
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_l {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index - 1` is not a digit
// - `index - 1` is not a digit separator
// - `index + 1` is not a digit separator
let prev = indexing!(@prev $self, $index);
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(prev).map_or(true, |&x| !$self.is_digit(x) && !$self.is_digit_separator(x)) &&
slc.get(next).map_or(true, |&x| !$self.is_digit_separator(x))
}};
(@first $self:ident) => {
is_l!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: Previous must have been a digit so this cannot be valid.
false
}};
(@internal $self:ident) => {
is_l!(@internal $self, $self.byte.index)
};
}
/// Determine if one or more digit separators are leading.
///
/// # Examples
///
/// - `__123`- valid
/// - `+__123`- valid
/// - `+__+123`- valid
/// - `+__.123`- valid
/// - `._123`- valid
/// - `_+123`- invalid
/// - `_123`- valid
/// - `+_123`- valid
///
/// Having a subsequent sign character is fine since it might
/// be part of a partial parser.
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_lc {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index - 1` is not a digit after removing digit separators
let prev = indexing!(@prevc $self, $index);
let slc = $self.byte.slc;
slc.get(prev).map_or(true, |&x| !$self.is_digit(x))
}};
(@first $self:ident) => {
is_lc!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: Previous must have been a digit so this cannot be valid.
false
}};
(@internal $self:ident) => {
is_lc!(@internal $self, $self.byte.index)
};
}
/// Determine if a single digit separator is trailing.
///
/// # Examples
///
/// - `123_`- valid
/// - `123__`- invalid
/// - `123_.`- valid
/// - `123__.`- invalid
/// - `123_1`- invalid
/// - `123__1`- invalid
/// - _: valid
/// - _+: valid
/// - 1_+: valid
///
/// Having a subsequent sign character is fine since it might
/// be part of a partial parser.
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_t {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index + 1` is not a digit
// - `index + 1` is not a digit separator
// - `index - 1` is not a digit separator
let prev = indexing!(@prev $self, $index);
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(true, |&x| !$self.is_digit(x) && !$self.is_digit_separator(x)) &&
slc.get(prev).map_or(true, |&x| !$self.is_digit_separator(x))
}};
(@first $self:ident) => {
is_t!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: We must have validated `prev`, so this just checks `next`.
// NOTE: The conditions here then are that:
// - `index + 1` is not a digit
// - `index + 1` is not a digit separator
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(true, |&x| !$self.is_digit(x) && !$self.is_digit_separator(x))
}};
(@internal $self:ident) => {
is_t!(@internal $self, $self.byte.index)
};
}
/// Determine if one or more digit separators are trailing.
///
/// # Examples
///
/// - `123_`- valid
/// - `123__`- valid
/// - `123_.`- valid
/// - `123__.`- valid
/// - `123_1`- invalid
/// - `123__1`- invalid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_tc {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index + 1` is not a digit
let next = indexing!(@nextc $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(true, |&x| !$self.is_digit(x))
}};
(@first $self:ident) => {
is_tc!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {
// NOTE: This is already optimized for the first case.
is_tc!(@first $self, $index)
};
(@internal $self:ident) => {
is_tc!(@internal $self, $self.byte.index)
};
}
/// Determine if the digit separator is leading or internal.
///
/// # Examples
///
/// - `__123`- invalid
/// - `+__123`- invalid
/// - `._123`- valid
/// - `_+123`- valid
/// - `_123`- valid
/// - `+_123`- valid
/// - `+1_23`- valid
/// - `+1__23`- invalid
/// - `+123_`- invalid
/// - `+123__`- invalid
/// - _: valid
/// - _+: valid
/// - 1_+: invalid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_il {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index + 1` is a digit
// - `index + 1` is not a digit separator
// - `index - 1` is not a digit separator
//
// # Logic
//
// If the previous character is a digit, then the
// next character must be a digit. If the previous
// character is not a digit, then the subsequent character can
// be anything besides a digit separator
let prev = indexing!(@prev $self, $index);
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
if slc.get(prev).map_or(false, |&x| $self.is_digit(x)) {
slc.get(next).map_or(false, |&x| $self.is_digit(x))
} else {
slc.get(prev).map_or(true, |&x| !$self.is_digit_separator(x))
}
}};
(@first $self:ident) => {
is_il!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: We must have validated `prev`, so this just checks `next`.
// NOTE: The conditions here then are that:
// - `index + 1` is a digit
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(false, |&x| $self.is_digit(x))
}};
(@internal $self:ident) => {
is_il!(@internal $self, $self.byte.index)
};
}
/// Determine if consecutive digit separators are leading or internal.
///
/// # Examples
///
/// - `__123`- valid
/// - `+__123`- valid
/// - `._123`- valid
/// - `_+123`- valid
/// - `_123`- valid
/// - `+_123`- valid
/// - `+1_23`- valid
/// - `+1__23`- valid
/// - `+123_`- invalid
/// - `+123__`- invalid
/// - _: valid
/// - _+: valid
/// - 1_+: invalid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_ilc {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index + 1` is a digit after consuming digit separators
//
// # Logic
//
// We also need to consider the case where it's empty,
// that is, the previous one wasn't a digit if we don't
// have a digit.
let prev = indexing!(@prevc $self, $index);
let next = indexing!(@nextc $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(false, |&x| $self.is_digit(x)) ||
slc.get(prev).map_or(true, |&x| !$self.is_digit(x))
}};
(@first $self:ident) => {
is_ilc!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index + 1` is a digit after consuming digit separators
let next = indexing!(@nextc $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(true, |&x| $self.is_digit(x))
}};
(@internal $self:ident) => {
is_ilc!(@internal $self, $self.byte.index)
};
}
/// Determine if the digit separator is internal or trailing.
///
/// # Examples
///
/// - `__123`- valid
/// - `+__123`- valid
/// - `._123`- valid
/// - `_+123`- valid
/// - `_123`- valid
/// - `+_123`- valid
/// - `+1_23`- valid
/// - `+1__23`- valid
/// - `+123_`- invalid
/// - `+123__`- invalid
/// - _: valid
/// - _+: valid
/// - 1_+: invalid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_it {
(@first$self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index - 1` is a digit
// - `index - 1` is not a digit separator
// - `index + 1` is not a digit separator
//
// # Logic
//
// If the previous character is not a digit, there cannot
// be a digit for a following character. If the previous
// character is a digit, then the following one must be
// a digit as well.
let prev = indexing!(@prev $self, $index);
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
if slc.get(prev).map_or(false, |&x| $self.is_digit(x)) {
// Have a digit, any character besides a digit separator is valid
slc.get(next).map_or(true, |&x| !$self.is_digit_separator(x))
} else {
// Not a digit, so we cannot have a digit or a digit separator
slc.get(next).map_or(true, |&x| !$self.is_digit(x) && !$self.is_digit_separator(x))
}
}};
(@first$self:ident) => {
is_it!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: We must have validated `prev`, so this just checks `next`.
// NOTE: The conditions here then are that:
// - `index + 1` is not a digit separator
// Since we've previously had a digit, this is guaranteed to
// be internal or trailing.
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(true, |&x| !$self.is_digit_separator(x))
}};
(@internal $self:ident) => {
is_it!(@internal $self, $self.byte.index)
};
}
/// Determine if consecutive digit separators are internal or trailing.
///
/// # Examples
///
/// - `__123`- invalid
/// - `+__123`- invalid
/// - `._123`- invalid
/// - `_+123`- invalid
/// - `_123`- invalid
/// - `+_123`- invalid
/// - `+1_23`- valid
/// - `+1__23`- valid
/// - `+123_`- valid
/// - `+123__`- valid
/// - _: valid
/// - _+: valid
/// - 1_+: valid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_itc {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index - 1` is not a digit after consuming digit separators
//
// # Logic
//
// We also need to consider the case where it's empty,
// that is, the previous one wasn't a digit if we don't
// have a digit.
let prev = indexing!(@prevc $self, $index);
let next = indexing!(@nextc $self, $index);
let slc = $self.byte.slc;
slc.get(prev).map_or(false, |&x| !$self.is_digit(x)) ||
slc.get(next).map_or(true, |&x| !$self.is_digit(x))
}};
(@first $self:ident) => {
is_itc!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {
// NOTE: Previous must have been a digit so this must be valid.
true
};
(@internal $self:ident) => {
is_itc!(@internal $self, $self.byte.index)
};
}
/// Determine if the digit separator is leading or trailing.
///
/// # Examples
///
/// - `__123`- invalid
/// - `+__123`- invalid
/// - `._123`- valid
/// - `_+123`- valid
/// - `_123`- valid
/// - `+_123`- valid
/// - `+1_23`- invalid
/// - `+1__23`- invalid
/// - `+123_`- valid
/// - `+123__`- invalid
/// - _: valid
/// - _+: valid
/// - 1_+: valid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_lt {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - not (`index - 1` is a digit and `index + 1` is a digit)
// - `index - 1` is not a digit separator
// - `index + 1` is not a digit separator
let prev = indexing!(@prev $self, $index);
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
let prev_value = slc.get(prev);
let next_value = slc.get(next);
let is_prev_sep = prev_value.map_or(false, |&x| $self.is_digit_separator(x));
let is_prev_dig = prev_value.map_or(false, |&x| $self.is_digit(x));
let is_next_sep = next_value.map_or(false, |&x| $self.is_digit_separator(x));
let is_next_dig = next_value.map_or(false, |&x| $self.is_digit(x));
!is_prev_sep && !is_next_sep && !(is_prev_dig && is_next_dig)
}};
(@first $self:ident) => {
is_lt!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: We must have validated `prev`, so this just checks `next`.
// NOTE: The conditions here then are that:
// - `index + 1` is not a digit
// - `index + 1` is not a digit separator
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(true, |&x| !$self.is_digit(x) && !$self.is_digit_separator(x))
}};
(@internal $self:ident) => {
is_lt!(@internal $self, $self.byte.index)
};
}
/// Determine if consecutive digit separators are leading or trailing.
///
/// # Examples
///
/// - `__123`- valid
/// - `+__123`- valid
/// - `._123`- valid
/// - `_+123`- valid
/// - `_123`- valid
/// - `+_123`- valid
/// - `+1_23`- invalid
/// - `+1__23`- invalid
/// - `+123_`- valid
/// - `+123__`- valid
/// - _: valid
/// - _+: valid
/// - 1_+: valid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_ltc {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that (after consuming separators):
// - not (`index - 1` is a digit and `index + 1` is a digit)
let prev = indexing!(@prevc $self, $index);
let next = indexing!(@nextc $self, $index);
let slc = $self.byte.slc;
!(slc.get(prev).map_or(false, |&x| $self.is_digit(x)) && slc.get(next).map_or(false, |&x| $self.is_digit(x)))
}};
(@first $self:ident) => {
is_ltc!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: We must have validated `prev`, so this just checks `next`.
// NOTE: The conditions here then are that:
// - `index + 1` is not a digit
let next = indexing!(@nextc $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(true, |&x| !$self.is_digit(x))
}};
(@internal $self:ident) => {
is_ltc!(@internal $self, $self.byte.index)
};
}
/// Determine if a single digit separator is internal, leading, or trailing.
///
/// # Examples
///
/// - `__123`- invalid
/// - `+__123`- invalid
/// - `._123`- valid
/// - `_+123`- valid
/// - `_123`- valid
/// - `+_123`- valid
/// - `+1_23`- valid
/// - `+1__23`- invalid
/// - `+123_`- valid
/// - `+123__`- invalid
/// - _: valid
/// - _+: valid
/// - 1_+: valid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_ilt {
(@first $self:ident, $index:expr) => {{
// NOTE: The conditions here then are that:
// - `index + 1` is not a digit separator
// - `index - 1` is not a digit separator
let prev = indexing!(@prev $self, $index);
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
!slc.get(next).map_or(false, |&x| $self.is_digit_separator(x)) &&
!slc.get(prev).map_or(false, |&x| $self.is_digit_separator(x))
}};
(@first $self:ident) => {
is_ilt!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {{
// NOTE: We must have validated `prev`, so this just checks `next`.
// NOTE: The conditions here then are that:
// - `index + 1` is not a digit separator
let next = indexing!(@next $self, $index);
let slc = $self.byte.slc;
slc.get(next).map_or(true, |&x| !$self.is_digit_separator(x))
}};
(@internal $self:ident) => {
is_ilt!(@internal $self, $self.byte.index)
};
}
/// Determine if consecutive digit separators are internal, leading, or
/// trailing.
///
/// This is always true.
///
/// # Examples
///
/// - `__123`- valid
/// - `+__123`- valid
/// - `._123`- valid
/// - `_+123`- valid
/// - `_123`- valid
/// - `+_123`- valid
/// - `+1_23`- valid
/// - `+1__23`- valid
/// - `+123_`- valid
/// - `+123__`- valid
/// - _: valid
/// - _+: valid
/// - 1_+: valid
///
/// # Preconditions
///
/// Assumes `slc[index]` is a digit separator.
macro_rules! is_iltc {
(@first $self:ident, $index:expr) => {
true
};
(@first $self:ident) => {
is_iltc!(@first $self, $self.byte.index)
};
(@internal $self:ident, $index:expr) => {
true
};
(@internal $self:ident) => {
is_iltc!(@internal $self, $self.byte.index)
};
}
// PEEK
// ----
/// Consumes 1 or more digit separators.
/// Peeks the next token that's not a digit separator.
macro_rules! peek_1 {
($self:ident, $is_skip:ident) => {{
// This will consume a single, non-consecutive digit separators.
let index = $self.cursor();
let buffer = $self.get_buffer();
let value = buffer.get(index)?;
let is_digit_separator = $self.is_digit_separator(*value);
// NOTE: We can do some pretty major optimizations for internal values,
// since we can check the location and don't need to check previous values.
if is_digit_separator {
// NOTE: This cannot iteratively search for the next value,
// or else the consecutive digit separator has no effect (#96).
let is_skip = if $self.current_count() == 0 {
$is_skip!(@first $self)
} else {
$is_skip!(@internal $self)
};
if is_skip {
// SAFETY: Safe since `index < buffer.len()`, so `index + 1 <= buffer.len()``
unsafe { $self.set_cursor(index + 1) };
buffer.get(index + 1)
} else {
Some(value)
}
} else {
// Have 1 of 2 conditions:
// 1. A non-digit separator character.
// 2. A digit separator that is not valid in the context.
Some(value)
}
}};
}
/// Consumes 1 or more digit separators.
/// Peeks the next token that's not a digit separator.
macro_rules! peek_n {
($self:ident, $is_skip:ident) => {{
// This will consume consecutive digit separators.
let mut index = $self.cursor();
let buffer = $self.get_buffer();
let value = buffer.get(index)?;
let is_digit_separator = $self.is_digit_separator(*value);
// NOTE: We can do some pretty major optimizations for internal values,
// since we can check the location and don't need to check previous values.
if is_digit_separator {
let is_skip = if $self.current_count() == 0 {
$is_skip!(@first $self)
} else {
$is_skip!(@internal $self)
};
if is_skip {
// Have a skippable digit separator: keep incrementing until we find
// a non-digit separator character. Don't need any complex checks
// here, since we've already done them above.
index += 1;
while index < buffer.len()
&& buffer.get(index).map_or(false, |&x| $self.is_digit_separator(x))
{
index += 1;
}
// SAFETY: Safe since `index <= buffer.len()`.
unsafe { $self.set_cursor(index) };
buffer.get(index)
} else {
Some(value)
}
} else {
// Have 1 of 2 conditions:
// 1. A non-digit separator character.
// 2. A digit separator that is not valid in the context.
Some(value)
}
}};
}
/// Consumes no digit separators and peeks the next value.
macro_rules! peek_noskip {
($self:ident) => {
$self.byte.slc.get($self.byte.index)
};
}
/// Consumes at most 1 leading digit separator and peeks the next value.
macro_rules! peek_l {
($self:ident) => {
peek_1!($self, is_l)
};
}
/// Consumes at most 1 internal digit separator and peeks the next value.
macro_rules! peek_i {
($self:ident) => {
peek_1!($self, is_i)
};
}
/// Consumes at most 1 trailing digit separator and peeks the next value.
macro_rules! peek_t {
($self:ident) => {
peek_1!($self, is_t)
};
}
/// Consumes at most 1 internal/leading digit separator and peeks the next
/// value.
macro_rules! peek_il {
($self:ident) => {
peek_1!($self, is_il)
};
}
/// Consumes at most 1 internal/trailing digit separator and peeks the next
/// value.
macro_rules! peek_it {
($self:ident) => {
peek_1!($self, is_it)
};
}
/// Consumes at most 1 leading/trailing digit separator and peeks the next
/// value.
macro_rules! peek_lt {
($self:ident) => {
peek_1!($self, is_lt)
};
}
/// Consumes at most 1 digit separator and peeks the next value.
macro_rules! peek_ilt {
($self:ident) => {
peek_1!($self, is_ilt)
};
}
/// Consumes 1 or more leading digit separators and peeks the next value.
macro_rules! peek_lc {
($self:ident) => {
peek_n!($self, is_lc)
};
}
/// Consumes 1 or more internal digit separators and peeks the next value.
macro_rules! peek_ic {
($self:ident) => {
peek_n!($self, is_ic)
};
}
/// Consumes 1 or more trailing digit separators and peeks the next value.
macro_rules! peek_tc {
($self:ident) => {
peek_n!($self, is_tc)
};
}
/// Consumes 1 or more internal/leading digit separators and peeks the next
/// value.
macro_rules! peek_ilc {
($self:ident) => {
peek_n!($self, is_ilc)
};
}
/// Consumes 1 or more internal/trailing digit separators and peeks the next
/// value.
macro_rules! peek_itc {
($self:ident) => {
peek_n!($self, is_itc)
};
}
/// Consumes 1 or more leading/trailing digit separators and peeks the next
/// value.
macro_rules! peek_ltc {
($self:ident) => {
peek_n!($self, is_ltc)
};
}
/// Consumes 1 or more digit separators and peeks the next value.
macro_rules! peek_iltc {
($self:ident) => {
peek_n!($self, is_iltc)
};
}
// AS DIGITS
// ---------
/// Trait to simplify creation of a `Bytes` object.
pub trait AsBytes<'a> {
/// Create `Bytes` from object.
fn bytes<const FORMAT: u128>(&'a self) -> Bytes<'a, FORMAT>;
}
impl<'a> AsBytes<'a> for [u8] {
#[inline(always)]
fn bytes<const FORMAT: u128>(&'a self) -> Bytes<'a, FORMAT> {
Bytes::new(self)
}
}
// DIGITS
// ------
/// Slice iterator that skips characters matching a given value.
///
/// This wraps an iterator over a contiguous block of memory,
/// and only returns values that are not equal to skip.
///
/// The format allows us to dictate the actual behavior of
/// the iterator: in what contexts does it skip digit separators.
///
/// `FORMAT` is required to tell us what the digit separator is, and where
/// the digit separators are allowed, as well tell us the radix.
/// The radix is required to allow us to differentiate digit from
/// non-digit characters (see [`DigitSeparators`](/docs/DigitSeparators.md)
/// for a detailed explanation on why).
#[derive(Clone)]
pub struct Bytes<'a, const FORMAT: u128> {
/// The raw slice for the iterator.
slc: &'a [u8],
/// Current index of the iterator in the slice.
index: usize,
/// The current count of integer digits returned by the iterator.
/// This is only used if the iterator is not contiguous.
integer_count: usize,
/// The current count of fraction digits returned by the iterator.
/// This is only used if the iterator is not contiguous.
fraction_count: usize,
/// The current count of exponent digits returned by the iterator.
/// This is only used if the iterator is not contiguous.
exponent_count: usize,
}
impl<'a, const FORMAT: u128> Bytes<'a, FORMAT> {
/// Create new byte object.
#[inline(always)]
pub const fn new(slc: &'a [u8]) -> Self {
Self {
slc,
index: 0,
integer_count: 0,
fraction_count: 0,
exponent_count: 0,
}
}
/// Initialize the slice from raw parts.
///
/// # Safety
/// This is safe if and only if the index is <= `slc.len()`.
/// For this reason, since it's easy to get wrong, we only
/// expose it to our `DigitsIterator`s and nothing else.
///
/// This is only ever used for contiguous iterators. However,
/// it's not guaranteed to only valid for our contiguous
/// iterators.
#[inline(always)]
const unsafe fn from_parts(slc: &'a [u8], index: usize) -> Self {
debug_assert!(index <= slc.len());
Self {
slc,
index,
integer_count: 0,
fraction_count: 0,
exponent_count: 0,
}
}
/// Get iterator over integer digits.
#[inline(always)]
pub fn integer_iter<'b>(&'b mut self) -> IntegerDigitsIterator<'a, 'b, FORMAT> {
IntegerDigitsIterator {
byte: self,
}
}
/// Get iterator over fraction digits.
#[inline(always)]
pub fn fraction_iter<'b>(&'b mut self) -> FractionDigitsIterator<'a, 'b, FORMAT> {
FractionDigitsIterator {
byte: self,
}
}
/// Get iterator over exponent digits.
#[inline(always)]
pub fn exponent_iter<'b>(&'b mut self) -> ExponentDigitsIterator<'a, 'b, FORMAT> {
ExponentDigitsIterator {
byte: self,
}
}
/// Get iterator over special floating point values.
#[inline(always)]
pub fn special_iter<'b>(&'b mut self) -> SpecialDigitsIterator<'a, 'b, FORMAT> {
SpecialDigitsIterator {
byte: self,
}
}
/// Internal implementation that handles if it's contiguous.
///
/// # Safety
///
/// Safe if the buffer has at least `N` elements.
#[inline(always)]
unsafe fn step_by_unchecked_impl(&mut self, count: usize, is_contiguous: bool) {
// NOTE: THIS IS NOT a duplicate calling `step_by_unchecked` from a digits
// iterator on the byte, since they can have different contiguousness.
if is_contiguous {
// Contiguous, can skip most of these checks.
debug_assert!(self.as_slice().len() >= count);
} else {
// Since this isn't contiguous, it only works
// if the value is in the range `[0, 1]`.
// We also need to make sure the **current** value
// isn't a digit separator.
let format = NumberFormat::<{ FORMAT }> {};
debug_assert!(self.as_slice().len() >= count);
debug_assert!(count == 0 || count == 1);
debug_assert!(
count == 0 || self.slc.get(self.index) != Some(&format.digit_separator())
);
}
self.index += count;
}
/// Internal implementation that handles if it's contiguous.
///
/// If it's contiguous or not does not affect the safety guarantees,
/// however, it can affect correctness.
///
/// # Safety
///
/// Safe if the buffer has at least `size_of::<V>` elements.
#[inline(always)]
unsafe fn peek_many_unchecked_impl<V>(&self, is_contiguous: bool) -> V {
// NOTE: THIS IS NOT a duplicate calling `peek_many_unchecked` from a digits
// iterator on the byte, since they can have different contiguousness.
debug_assert!(is_contiguous);
debug_assert!(self.as_slice().len() >= mem::size_of::<V>());
let slc = self.as_slice();
// SAFETY: safe as long as the slice has at least count elements.
unsafe { ptr::read_unaligned::<V>(slc.as_ptr() as *const _) }
}
}
unsafe impl<'a, const FORMAT: u128> Iter<'a> for Bytes<'a, FORMAT> {
/// If each yielded value is adjacent in memory.
const IS_CONTIGUOUS: bool = NumberFormat::<{ FORMAT }>::DIGIT_SEPARATOR == 0;
#[inline(always)]
fn get_buffer(&self) -> &'a [u8] {
self.slc
}
/// Get the current index of the iterator in the slice.
#[inline(always)]
fn cursor(&self) -> usize {
self.index
}
/// Set the current index of the iterator in the slice.
///
/// # Safety
///
/// Safe if `index <= self.buffer_length()`.
#[inline(always)]
unsafe fn set_cursor(&mut self, index: usize) {
debug_assert!(index <= self.buffer_length());
self.index = index;
}
/// Get the current number of digits returned by the iterator.
///
/// For contiguous iterators, this can include the sign character, decimal
/// point, and the exponent sign (that is, it is always the cursor). For
/// non-contiguous iterators, this must always be the only the number of
/// digits returned.
#[inline(always)]
fn current_count(&self) -> usize {
// If the buffer is contiguous, then we don't need to track the
// number of values: the current index is enough.
if Self::IS_CONTIGUOUS {
self.index
} else {
self.integer_count + self.fraction_count + self.exponent_count
}
}
#[inline(always)]
unsafe fn step_by_unchecked(&mut self, count: usize) {
// SAFETY: Safe if the buffer has at least `N` elements.
unsafe { self.step_by_unchecked_impl(count, Self::IS_CONTIGUOUS) }
}
#[inline(always)]
unsafe fn peek_many_unchecked<V>(&self) -> V {
// SAFETY: Safe if the buffer has at least `size_of::<V>` elements.
unsafe { self.peek_many_unchecked_impl(Self::IS_CONTIGUOUS) }
}
}
// ITERATOR HELPERS
// ----------------
/// Create skip iterator definition.
macro_rules! skip_iterator {
($iterator:ident, $doc:literal) => {
#[doc = $doc]
pub struct $iterator<'a: 'b, 'b, const FORMAT: u128> {
/// The internal byte object for the skip iterator.
byte: &'b mut Bytes<'a, FORMAT>,
}
};
}
macro_rules! is_sign {
() => {
pub const fn is_sign(&self, value: u8) -> bool {
matches!(value, b'+' | b'-')
}
};
}
macro_rules! is_digit_separator {
($format:ident) => {
/// Determine if the character is a digit separator.
pub const fn is_digit_separator(&self, value: u8) -> bool {
let format = NumberFormat::<{ $format }> {};
let digit_separator = format.digit_separator();
if digit_separator == 0 {
// Check at compile time if we have an invalid digit separator.
// b'\x00', or the NUL character, is this invalid value.
false
} else {
value == digit_separator
}
}
};
}
/// Create impl block for skip iterator.
macro_rules! skip_iterator_impl {
($iterator:ident, $radix_cb:ident) => {
impl<'a: 'b, 'b, const FORMAT: u128> $iterator<'a, 'b, FORMAT> {
is_sign!();
is_digit_separator!(FORMAT);
/// Create a new digits iterator from the bytes underlying item.
#[inline(always)]
pub fn new(byte: &'b mut Bytes<'a, FORMAT>) -> Self {
Self {
byte,
}
}
/// Take the first N digits from the iterator.
///
/// This only takes the digits if we have a contiguous iterator.
/// It takes the digits, validating the bounds, and then advanced
/// the iterators state. It does not support non-contiguous iterators
/// since we would lose information on the count.
#[cfg_attr(not(feature = "compact"), inline(always))]
#[allow(clippy::assertions_on_constants)] // reason="ensuring safety invariants are valid"
pub fn take_n(&mut self, n: usize) -> Option<Bytes<'a, FORMAT>> {
if Self::IS_CONTIGUOUS {
let end = self.byte.slc.len().min(n + self.cursor());
// NOTE: The compiler should be able to optimize this out.
let slc: &[u8] = &self.byte.slc[..end];
// SAFETY: Safe since we just ensured the underlying slice has that count
// elements, so both the underlying slice for this and this **MUST**
// have at least count elements. We do static checking on the bounds for this.
unsafe {
let byte: Bytes<'_, FORMAT> = Bytes::from_parts(slc, self.cursor());
unsafe { self.set_cursor(end) };
Some(byte)
}
} else {
None
}
}
}
};
}
/// Create impl Iterator block for skip iterator.
macro_rules! skip_iterator_iterator_impl {
($iterator:ident) => {
impl<'a: 'b, 'b, const FORMAT: u128> Iterator for $iterator<'a, 'b, FORMAT> {
type Item = &'a u8;
#[inline(always)]
fn next(&mut self) -> Option<Self::Item> {
// Peek will handle everything properly internally.
let value = self.peek()?;
// Increment the index so we know not to re-fetch it.
self.byte.index += 1;
// NOTE: Only increment the count if it's not contiguous, otherwise,
// this is an unnecessary performance penalty. We also need
// to check if it's a digit, which adds on additional cost but
// there's not much else we can do. Hopefully the previous inlining
// checks will minimize the performance hit.
if !Self::IS_CONTIGUOUS && self.is_digit(*value) {
self.increment_count();
}
Some(value)
}
}
};
}
/// Create base methods for the Iter block of a skip iterator.
macro_rules! skip_iterator_iter_base {
($format:ident, $mask:ident, $count:ident) => {
// It's contiguous if we don't skip over any values.
// IE, the digit separator flags for the iterator over
// the digits doesn't skip any values.
const IS_CONTIGUOUS: bool = $format & flags::$mask == 0;
#[inline(always)]
fn get_buffer(&self) -> &'a [u8] {
self.byte.get_buffer()
}
#[inline(always)]
fn cursor(&self) -> usize {
self.byte.cursor()
}
#[inline(always)]
unsafe fn set_cursor(&mut self, index: usize) {
debug_assert!(index <= self.buffer_length());
// SAFETY: safe if `index <= self.buffer_length()`.
unsafe { self.byte.set_cursor(index) };
}
/// Get the current number of digits returned by the iterator.
///
/// For contiguous iterators, this can include the sign character, decimal
/// point, and the exponent sign (that is, it is always the cursor). For
/// non-contiguous iterators, this must always be the only the number of
/// digits returned.
#[inline(always)]
fn current_count(&self) -> usize {
if Self::IS_CONTIGUOUS {
self.byte.current_count()
} else {
self.byte.$count
}
}
#[inline(always)]
unsafe fn step_by_unchecked(&mut self, count: usize) {
// SAFETY: Safe if the buffer has at least `N` elements.
unsafe { self.byte.step_by_unchecked_impl(count, Self::IS_CONTIGUOUS) }
}
#[inline(always)]
unsafe fn peek_many_unchecked<V>(&self) -> V {
// SAFETY: Safe if the buffer has at least `size_of::<V>` elements.
unsafe { self.byte.peek_many_unchecked_impl(Self::IS_CONTIGUOUS) }
}
};
}
/// Create base methods for the `DigitsIter` block of a skip iterator.
macro_rules! skip_iterator_digits_iter_base {
() => {
#[inline(always)]
fn is_consumed(&mut self) -> bool {
self.peek().is_none()
}
};
}
/// Create impl `ByteIter` block for skip iterator.
macro_rules! skip_iterator_bytesiter_impl {
($iterator:ident, $mask:ident, $count:ident, $i:ident, $l:ident, $t:ident, $c:ident) => {
unsafe impl<'a: 'b, 'b, const FORMAT: u128> Iter<'a> for $iterator<'a, 'b, FORMAT> {
skip_iterator_iter_base!(FORMAT, $mask, $count);
}
impl<'a: 'b, 'b, const FORMAT: u128> DigitsIter<'a> for $iterator<'a, 'b, FORMAT> {
skip_iterator_digits_iter_base!();
/// Increment the number of digits that have been returned by the iterator.
///
/// For contiguous iterators, this is a no-op. For non-contiguous iterators,
/// this increments the count by 1.
#[inline(always)]
fn increment_count(&mut self) {
self.byte.$count += 1;
}
/// Peek the next value of the iterator, without consuming it.
///
/// Note that this can modify the internal state, by skipping digits
/// for iterators that find the first non-zero value, etc. We optimize
/// this for the case where we have contiguous iterators, since
/// non-contiguous iterators already have a major performance penalty.
///
/// Checking if the character is a digit in the `next()` implementation
/// after skipping characters can:
/// 1. Likely be optimized out due to the use of macros and inlining.
/// 2. Is a small amount of overhead compared to the branching on
/// characters,
#[inline(always)]
fn peek(&mut self) -> Option<<Self as Iterator>::Item> {
let format = NumberFormat::<{ FORMAT }> {};
const I: u128 = flags::$i;
const L: u128 = flags::$l;
const T: u128 = flags::$t;
const C: u128 = flags::$c;
const IL: u128 = I | L;
const IT: u128 = I | T;
const LT: u128 = L | T;
const ILT: u128 = I | L | T;
const IC: u128 = I | C;
const LC: u128 = L | C;
const TC: u128 = T | C;
const ILC: u128 = IL | C;
const ITC: u128 = IT | C;
const LTC: u128 = LT | C;
const ILTC: u128 = ILT | C;
match format.digit_separator_flags() & flags::$mask {
0 => peek_noskip!(self),
I => peek_i!(self),
L => peek_l!(self),
T => peek_t!(self),
IL => peek_il!(self),
IT => peek_it!(self),
LT => peek_lt!(self),
ILT => peek_ilt!(self),
IC => peek_ic!(self),
LC => peek_lc!(self),
TC => peek_tc!(self),
ILC => peek_ilc!(self),
ITC => peek_itc!(self),
LTC => peek_ltc!(self),
ILTC => peek_iltc!(self),
_ => unreachable!(),
}
}
/// Determine if the character is a digit.
#[inline(always)]
fn is_digit(&self, value: u8) -> bool {
let format = NumberFormat::<{ FORMAT }> {};
char_is_digit_const(value, format.mantissa_radix())
}
}
};
}
// INTEGER DIGITS ITERATOR
// -----------------------
skip_iterator!(IntegerDigitsIterator, "Iterator that skips over digit separators in the integer.");
skip_iterator_impl!(IntegerDigitsIterator, mantissa_radix);
skip_iterator_iterator_impl!(IntegerDigitsIterator);
skip_iterator_bytesiter_impl!(
IntegerDigitsIterator,
INTEGER_DIGIT_SEPARATOR_FLAG_MASK,
integer_count,
INTEGER_INTERNAL_DIGIT_SEPARATOR,
INTEGER_LEADING_DIGIT_SEPARATOR,
INTEGER_TRAILING_DIGIT_SEPARATOR,
INTEGER_CONSECUTIVE_DIGIT_SEPARATOR
);
// FRACTION DIGITS ITERATOR
// ------------------------
skip_iterator!(
FractionDigitsIterator,
"Iterator that skips over digit separators in the fraction."
);
skip_iterator_impl!(FractionDigitsIterator, mantissa_radix);
skip_iterator_iterator_impl!(FractionDigitsIterator);
skip_iterator_bytesiter_impl!(
FractionDigitsIterator,
FRACTION_DIGIT_SEPARATOR_FLAG_MASK,
fraction_count,
FRACTION_INTERNAL_DIGIT_SEPARATOR,
FRACTION_LEADING_DIGIT_SEPARATOR,
FRACTION_TRAILING_DIGIT_SEPARATOR,
FRACTION_CONSECUTIVE_DIGIT_SEPARATOR
);
// EXPONENT DIGITS ITERATOR
// ------------------------
skip_iterator!(
ExponentDigitsIterator,
"Iterator that skips over digit separators in the exponent."
);
skip_iterator_impl!(ExponentDigitsIterator, exponent_radix);
skip_iterator_iterator_impl!(ExponentDigitsIterator);
skip_iterator_bytesiter_impl!(
ExponentDigitsIterator,
EXPONENT_DIGIT_SEPARATOR_FLAG_MASK,
exponent_count,
EXPONENT_INTERNAL_DIGIT_SEPARATOR,
EXPONENT_LEADING_DIGIT_SEPARATOR,
EXPONENT_TRAILING_DIGIT_SEPARATOR,
EXPONENT_CONSECUTIVE_DIGIT_SEPARATOR
);
// SPECIAL DIGITS ITERATOR
// -----------------------
skip_iterator!(
SpecialDigitsIterator,
"Iterator that skips over digit separators in special floats."
);
skip_iterator_iterator_impl!(SpecialDigitsIterator);
impl<'a: 'b, 'b, const FORMAT: u128> SpecialDigitsIterator<'a, 'b, FORMAT> {
is_sign!();
is_digit_separator!(FORMAT);
}
unsafe impl<'a: 'b, 'b, const FORMAT: u128> Iter<'a> for SpecialDigitsIterator<'a, 'b, FORMAT> {
skip_iterator_iter_base!(FORMAT, SPECIAL_DIGIT_SEPARATOR, integer_count);
}
impl<'a: 'b, 'b, const FORMAT: u128> DigitsIter<'a> for SpecialDigitsIterator<'a, 'b, FORMAT> {
skip_iterator_digits_iter_base!();
// Always a no-op.
#[inline(always)]
fn increment_count(&mut self) {
}
/// Peek the next value of the iterator, without consuming it.
#[inline(always)]
fn peek(&mut self) -> Option<<Self as Iterator>::Item> {
let format = NumberFormat::<{ FORMAT }> {};
if format.special_digit_separator() {
peek_iltc!(self)
} else {
peek_noskip!(self)
}
}
/// Determine if the character is a digit.
#[inline(always)]
fn is_digit(&self, value: u8) -> bool {
let format = NumberFormat::<{ FORMAT }> {};
char_is_digit_const(value, format.mantissa_radix())
}
}