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Write char::DebugEscape sequences using write_str

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Instead of writing each `char` of an escape sequence one by one,
this delegates to `Display`, which uses `write_str` internally
in order to write the whole escape sequence at once.
This commit is contained in:
Arpad Borsos 2024-05-01 10:32:26 +02:00
parent f092f73c11
commit 0334c45bb5
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GPG key ID: FC7BCA77824B3298
2 changed files with 6 additions and 9 deletions
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4
library/core/benches/str/debug.rs
View file

@ -44,7 +44,7 @@ fn ascii_escapes(b: &mut Bencher) {
assert_fmt( assert_fmt(
s, s,
r#""some\tmore\tascii\ttext\nthis time with some \"escapes\", also 64 byte""#, r#""some\tmore\tascii\ttext\nthis time with some \"escapes\", also 64 byte""#,
21, 15,
); );
b.iter(|| { b.iter(|| {
black_box(format!("{:?}", black_box(s))); black_box(format!("{:?}", black_box(s)));
@ -72,7 +72,7 @@ fn mostly_unicode(b: &mut Bencher) {
#[bench] #[bench]
fn mixed(b: &mut Bencher) { fn mixed(b: &mut Bencher) {
let s = "\"❤️\"\n\"hűha ez betű\"\n\"кириллических букв\"."; let s = "\"❤️\"\n\"hűha ez betű\"\n\"кириллических букв\".";
assert_fmt(s, r#""\"❤\u{fe0f}\"\n\"hűha ez betű\"\n\"кириллических букв\".""#, 36); assert_fmt(s, r#""\"❤\u{fe0f}\"\n\"hűha ez betű\"\n\"кириллических букв\".""#, 21);
b.iter(|| { b.iter(|| {
black_box(format!("{:?}", black_box(s))); black_box(format!("{:?}", black_box(s)));
}); });

11
library/core/src/fmt/mod.rs
View file

@ -2409,9 +2409,7 @@ impl Debug for str {
// If char needs escaping, flush backlog so far and write, else skip // If char needs escaping, flush backlog so far and write, else skip
if esc.len() != 1 { if esc.len() != 1 {
f.write_str(&self[from..i])?; f.write_str(&self[from..i])?;
for c in esc { Display::fmt(&esc, f)?;
f.write_char(c)?;
}
from = i + c.len_utf8(); from = i + c.len_utf8();
} }
} }
@ -2431,13 +2429,12 @@ impl Display for str {
impl Debug for char { impl Debug for char {
fn fmt(&self, f: &mut Formatter<'_>) -> Result { fn fmt(&self, f: &mut Formatter<'_>) -> Result {
f.write_char('\'')?; f.write_char('\'')?;
for c in self.escape_debug_ext(EscapeDebugExtArgs { let esc = self.escape_debug_ext(EscapeDebugExtArgs {
escape_grapheme_extended: true, escape_grapheme_extended: true,
escape_single_quote: true, escape_single_quote: true,
escape_double_quote: false, escape_double_quote: false,
}) { });
f.write_char(c)? Display::fmt(&esc, f)?;
}
f.write_char('\'') f.write_char('\'')
} }
} }