From ef3305449b7166153cce085d1cc5ffd30f470d0b Mon Sep 17 00:00:00 2001
From: ltdk <usr@ltdk.xyz>
Date: Mon, 3 Jul 2023 13:11:39 -0400
Subject: [PATCH] Implement Step for AsciiChar
---
library/core/src/iter/range.rs | 45 +++++++++++++++++++++++++++++++-
library/core/tests/iter/range.rs | 18 ++++++++++++-
library/core/tests/lib.rs | 2 ++
tests/ui/range/range-1.stderr | 2 +-
4 files changed, 64 insertions(+), 3 deletions(-)
diff --git a/library/core/src/iter/range.rs b/library/core/src/iter/range.rs
index 462f7170a55..44feb0a5638 100644
--- a/library/core/src/iter/range.rs
+++ b/library/core/src/iter/range.rs
@@ -1,3 +1,4 @@
+use crate::ascii::Char as AsciiChar;
use crate::convert::TryFrom;
use crate::mem;
use crate::num::NonZeroUsize;
@@ -14,7 +15,7 @@ macro_rules! unsafe_impl_trusted_step {
unsafe impl TrustedStep for $type {}
)*};
}
-unsafe_impl_trusted_step![char i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize];
+unsafe_impl_trusted_step![AsciiChar char i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize];
/// Objects that have a notion of *successor* and *predecessor* operations.
///
@@ -484,6 +485,48 @@ impl Step for char {
}
}
+#[unstable(feature = "step_trait", reason = "recently redesigned", issue = "42168")]
+impl Step for AsciiChar {
+ #[inline]
+ fn steps_between(&start: &AsciiChar, &end: &AsciiChar) -> Option<usize> {
+ Step::steps_between(&start.to_u8(), &end.to_u8())
+ }
+
+ #[inline]
+ fn forward_checked(start: AsciiChar, count: usize) -> Option<AsciiChar> {
+ let end = Step::forward_checked(start.to_u8(), count)?;
+ AsciiChar::from_u8(end)
+ }
+
+ #[inline]
+ fn backward_checked(start: AsciiChar, count: usize) -> Option<AsciiChar> {
+ let end = Step::backward_checked(start.to_u8(), count)?;
+
+ // SAFETY: Values below that of a valid ASCII character are also valid ASCII
+ Some(unsafe { AsciiChar::from_u8_unchecked(end) })
+ }
+
+ #[inline]
+ unsafe fn forward_unchecked(start: AsciiChar, count: usize) -> AsciiChar {
+ // SAFETY: Caller asserts that result is a valid ASCII character,
+ // and therefore it is a valid u8.
+ let end = unsafe { Step::forward_unchecked(start.to_u8(), count) };
+
+ // SAFETY: Caller asserts that result is a valid ASCII character.
+ unsafe { AsciiChar::from_u8_unchecked(end) }
+ }
+
+ #[inline]
+ unsafe fn backward_unchecked(start: AsciiChar, count: usize) -> AsciiChar {
+ // SAFETY: Caller asserts that result is a valid ASCII character,
+ // and therefore it is a valid u8.
+ let end = unsafe { Step::backward_unchecked(start.to_u8(), count) };
+
+ // SAFETY: Caller asserts that result is a valid ASCII character.
+ unsafe { AsciiChar::from_u8_unchecked(end) }
+ }
+}
+
macro_rules! range_exact_iter_impl {
($($t:ty)*) => ($(
#[stable(feature = "rust1", since = "1.0.0")]
diff --git a/library/core/tests/iter/range.rs b/library/core/tests/iter/range.rs
index 0a77ecddb84..5b87d6c1fa0 100644
--- a/library/core/tests/iter/range.rs
+++ b/library/core/tests/iter/range.rs
@@ -1,5 +1,6 @@
-use core::num::NonZeroUsize;
use super::*;
+use core::ascii::Char as AsciiChar;
+use core::num::NonZeroUsize;
#[test]
fn test_range() {
@@ -39,6 +40,21 @@ fn test_char_range() {
assert_eq!(('\u{D7FF}'..'\u{E000}').size_hint(), (1, Some(1)));
}
+#[test]
+fn test_ascii_char_range() {
+ let from = AsciiChar::Null;
+ let to = AsciiChar::Delete;
+ assert!((from..=to).eq((from as u8..=to as u8).filter_map(AsciiChar::from_u8)));
+ assert!((from..=to).rev().eq((from as u8..=to as u8).filter_map(AsciiChar::from_u8).rev()));
+
+ assert_eq!((AsciiChar::CapitalA..=AsciiChar::CapitalZ).count(), 26);
+ assert_eq!((AsciiChar::CapitalA..=AsciiChar::CapitalZ).size_hint(), (26, Some(26)));
+ assert_eq!((AsciiChar::SmallA..=AsciiChar::SmallZ).count(), 26);
+ assert_eq!((AsciiChar::SmallA..=AsciiChar::SmallZ).size_hint(), (26, Some(26)));
+ assert_eq!((AsciiChar::Digit0..=AsciiChar::Digit9).count(), 10);
+ assert_eq!((AsciiChar::Digit0..=AsciiChar::Digit9).size_hint(), (10, Some(10)));
+}
+
#[test]
fn test_range_exhaustion() {
let mut r = 10..10;
diff --git a/library/core/tests/lib.rs b/library/core/tests/lib.rs
index d849561bb21..aac9250aa4f 100644
--- a/library/core/tests/lib.rs
+++ b/library/core/tests/lib.rs
@@ -2,6 +2,8 @@
#![feature(array_chunks)]
#![feature(array_methods)]
#![feature(array_windows)]
+#![feature(ascii_char)]
+#![feature(ascii_char_variants)]
#![feature(bigint_helper_methods)]
#![feature(cell_update)]
#![feature(const_align_offset)]
diff --git a/tests/ui/range/range-1.stderr b/tests/ui/range/range-1.stderr
index 277d9b2682d..ecfc56961ee 100644
--- a/tests/ui/range/range-1.stderr
+++ b/tests/ui/range/range-1.stderr
@@ -19,7 +19,7 @@ LL | for i in false..true {}
i64
i128
usize
- and 5 others
+ and 6 others
= note: required for `std::ops::Range<bool>` to implement `Iterator`
= note: required for `std::ops::Range<bool>` to implement `IntoIterator`