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percent_encoding: faster percent_encode_byte #814

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Merged
merged 1 commit into from
Feb 28, 2023
Merged

percent_encoding: faster percent_encode_byte #814

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11 changes: 8 additions & 3 deletions percent_encoding/src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -180,9 +180,9 @@ pub const NON_ALPHANUMERIC: &AsciiSet = &CONTROLS
/// assert_eq!("foo bar".bytes().map(percent_encode_byte).collect::<String>(),
/// "%66%6F%6F%20%62%61%72");
/// ```
#[inline]
pub fn percent_encode_byte(byte: u8) -> &'static str {
let index = usize::from(byte) * 3;
&"\
static ENC_TABLE: &[u8; 768] = b"\
%00%01%02%03%04%05%06%07%08%09%0A%0B%0C%0D%0E%0F\
%10%11%12%13%14%15%16%17%18%19%1A%1B%1C%1D%1E%1F\
%20%21%22%23%24%25%26%27%28%29%2A%2B%2C%2D%2E%2F\
Expand All @@ -199,7 +199,12 @@ pub fn percent_encode_byte(byte: u8) -> &'static str {
%D0%D1%D2%D3%D4%D5%D6%D7%D8%D9%DA%DB%DC%DD%DE%DF\
%E0%E1%E2%E3%E4%E5%E6%E7%E8%E9%EA%EB%EC%ED%EE%EF\
%F0%F1%F2%F3%F4%F5%F6%F7%F8%F9%FA%FB%FC%FD%FE%FF\
"[index..index + 3]
";

let index = usize::from(byte) * 3;
// SAFETY: ENC_TABLE is ascii-only, so any subset if it should be
// ascii-only too, which is valid utf8.
unsafe { str::from_utf8_unchecked(&ENC_TABLE[index..index + 3]) }
}

/// Percent-encode the given bytes with the given set.
Expand Down