Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Expand an optimization for short values to IgnoreCase in single-value SearchValues<string> #108368

Open
wants to merge 1 commit into
base: main
Choose a base branch
from
+10 −10
Open

Expand an optimization for short values to IgnoreCase in single-value SearchValues<string> #108368

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
20 changes: 10 additions & 10 deletions ...tem.Private.CoreLib/src/System/SearchValues/Strings/SingleStringSearchValuesThreeChars.cs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -31,6 +31,14 @@ internal sealed class SingleStringSearchValuesThreeChars<TValueLength, TCaseSens

private static bool IgnoreCase => typeof(TCaseSensitivity) != typeof(CaseSensitive);

// If the value is short (!TValueLength.AtLeast4Chars => 2 or 3 characters), the anchors already represent the whole value.
// With case-sensitive comparisons, we've therefore already confirmed the match.
// With case-insensitive comparisons, we've applied the CaseConversionMask to the input, so while the anchors likely matched, we can't be sure.
// An exception to that is if we know the value is composed of only ASCII letters, in which case masking the input can't produce false positives.
private static bool CanSkipAnchorMatchVerification =>
!TValueLength.AtLeast4Chars &&
(typeof(TCaseSensitivity) == typeof(CaseSensitive) || typeof(TCaseSensitivity) == typeof(CaseInsensitiveAsciiLetters));

public SingleStringSearchValuesThreeChars(HashSet<string>? uniqueValues, string value) : base(uniqueValues)
{
// We could have more than one entry in 'uniqueValues' if this value is an exact prefix of all the others.
Expand Down Expand Up @@ -327,11 +335,7 @@ private bool TryMatch(ref char searchSpaceStart, int searchSpaceLength, ref char

ValidateReadPosition(ref searchSpaceStart, searchSpaceLength, ref matchRef, _value.Length);

// If the value is short (!TValueLength.AtLeast4Chars => 2 or 3 characters), the anchors already represent the whole value.
// With case-sensitive comparisons, we've therefore already confirmed the match, so we can skip doing so here.
// With case-insensitive comparisons, we applied a mask to the input, so while the anchors likely matched, we can't be sure.
if ((typeof(TCaseSensitivity) == typeof(CaseSensitive) && !TValueLength.AtLeast4Chars) ||
TCaseSensitivity.Equals<TValueLength>(ref matchRef, _value))
if (CanSkipAnchorMatchVerification || TCaseSensitivity.Equals<TValueLength>(ref matchRef, _value))
{
offsetFromStart = (int)((nuint)Unsafe.ByteOffset(ref searchSpaceStart, ref matchRef) / 2);
return true;
Expand Down Expand Up @@ -359,11 +363,7 @@ private bool TryMatch(ref char searchSpaceStart, int searchSpaceLength, ref char

ValidateReadPosition(ref searchSpaceStart, searchSpaceLength, ref matchRef, _value.Length);

// If the value is short (!TValueLength.AtLeast4Chars => 2 or 3 characters), the anchors already represent the whole value.
// With case-sensitive comparisons, we've therefore already confirmed the match, so we can skip doing so here.
// With case-insensitive comparisons, we applied a mask to the input, so while the anchors likely matched, we can't be sure.
if ((typeof(TCaseSensitivity) == typeof(CaseSensitive) && !TValueLength.AtLeast4Chars) ||
TCaseSensitivity.Equals<TValueLength>(ref matchRef, _value))
if (CanSkipAnchorMatchVerification || TCaseSensitivity.Equals<TValueLength>(ref matchRef, _value))
{
offsetFromStart = (int)((nuint)Unsafe.ByteOffset(ref searchSpaceStart, ref matchRef) / 2);
return true;
Expand Down