diff --git a/Benchmarks/Text/StringExtensions/ToStringEnumerable.cs b/Benchmarks/Text/StringExtensions/ToStringEnumerable.cs index 43eef23ce..8d5d55f41 100644 --- a/Benchmarks/Text/StringExtensions/ToStringEnumerable.cs +++ b/Benchmarks/Text/StringExtensions/ToStringEnumerable.cs @@ -16,27 +16,28 @@ public class ToStringEnumerable /// [Benchmark] [ArgumentsSource (nameof (DataSource))] - public string Previous (IEnumerable runes, int size) + public string Previous (IEnumerable runes, int len) { - return StringAppendInLoop (runes); + return StringConcatInLoop (runes); } /// - /// Benchmark for current implementation with rune chars appending to StringBuilder. + /// Benchmark for current implementation with stackalloc char buffer and + /// fallback to rune chars appending to StringBuilder. /// /// /// [Benchmark (Baseline = true)] [ArgumentsSource (nameof (DataSource))] - public string Current (IEnumerable runes, int size) + public string Current (IEnumerable runes, int len) { return Tui.StringExtensions.ToString (runes); } /// - /// Previous implementation with string append in a loop. + /// Previous implementation with string concatenation in a loop. /// - private static string StringAppendInLoop (IEnumerable runes) + private static string StringConcatInLoop (IEnumerable runes) { var str = string.Empty; @@ -50,21 +51,34 @@ public class ToStringEnumerable public IEnumerable DataSource () { - string textSource = - """ - Ĺόŕéḿ íṕśúḿ d́όĺόŕ śít́ áḿét́, ćόńśéćt́ét́úŕ ád́íṕíśćíńǵ éĺít́. Ṕŕáéśéńt́ q́úíś ĺúćt́úś éĺít́. Íńt́éǵéŕ út́ áŕćú éǵét́ d́όĺόŕ śćéĺéŕíśq́úé ḿát́t́íś áć ét́ d́íáḿ. - Ṕéĺĺéńt́éśq́úé śéd́ d́áṕíb́úś ḿáśśá, v́éĺ t́ŕíśt́íq́úé d́úí. Śéd́ v́ít́áé ńéq́úé éú v́éĺít́ όŕńáŕé áĺíq́úét́. Út́ q́úíś όŕćí t́éḿṕόŕ, t́éḿṕόŕ t́úŕṕíś íd́, t́éḿṕúś ńéq́úé. - Ṕŕáéśéńt́ śáṕíéń t́úŕṕíś, όŕńáŕé v́éĺ ḿáúŕíś át́, v́áŕíúś śúśćíṕít́ áńt́é. Út́ ṕúĺv́íńáŕ t́úŕṕíś ḿáśśá, q́úíś ćúŕśúś áŕćú f́áúćíb́úś íń. - Óŕćí v́áŕíúś ńát́όq́úé ṕéńát́íb́úś ét́ ḿáǵńíś d́íś ṕáŕt́úŕíéńt́ ḿόńt́éś, ńáśćét́úŕ ŕíd́íćúĺúś ḿúś. F́úśćé át́ éx́ b́ĺáńd́ít́, ćόńv́áĺĺíś q́úáḿ ét́, v́úĺṕút́át́é ĺáćúś. - Śúśṕéńd́íśśé śít́ áḿét́ áŕćú út́ áŕćú f́áúćíb́úś v́áŕíúś. V́ív́áḿúś śít́ áḿét́ ḿáx́íḿúś d́íáḿ. Ńáḿ éx́ ĺéό, ṕh́áŕét́ŕá éú ĺόb́όŕt́íś át́, t́ŕíśt́íq́úé út́ f́éĺíś. - """; - - // Extra argument as workaround for the summary grouping different length collections to same baseline making comparison difficult. - int[] sizes = [1, 10, 100, textSource.Length / 2, textSource.Length]; - - foreach (int size in sizes) + // Extra length argument as workaround for the summary grouping + // different length collections to same baseline making comparison difficult. + foreach (string text in GetTextData ()) { - yield return [textSource.EnumerateRunes ().Take (size).ToArray (), size]; + Rune [] runes = [..text.EnumerateRunes ()]; + yield return [runes, runes.Length]; } } + + private IEnumerable GetTextData () + { + string textSource = + """ + Ĺόŕéḿ íṕśúḿ d́όĺόŕ śít́ áḿét́, ćόńśéćt́ét́úŕ ád́íṕíśćíńǵ éĺít́. Ṕŕáéśéńt́ q́úíś ĺúćt́úś éĺít́. Íńt́éǵéŕ út́ áŕćú éǵét́ d́όĺόŕ śćéĺéŕíśq́úé ḿát́t́íś áć ét́ d́íáḿ. + Ṕéĺĺéńt́éśq́úé śéd́ d́áṕíb́úś ḿáśśá, v́éĺ t́ŕíśt́íq́úé d́úí. Śéd́ v́ít́áé ńéq́úé éú v́éĺít́ όŕńáŕé áĺíq́úét́. Út́ q́úíś όŕćí t́éḿṕόŕ, t́éḿṕόŕ t́úŕṕíś íd́, t́éḿṕúś ńéq́úé. + Ṕŕáéśéńt́ śáṕíéń t́úŕṕíś, όŕńáŕé v́éĺ ḿáúŕíś át́, v́áŕíúś śúśćíṕít́ áńt́é. Út́ ṕúĺv́íńáŕ t́úŕṕíś ḿáśśá, q́úíś ćúŕśúś áŕćú f́áúćíb́úś íń. + Óŕćí v́áŕíúś ńát́όq́úé ṕéńát́íb́úś ét́ ḿáǵńíś d́íś ṕáŕt́úŕíéńt́ ḿόńt́éś, ńáśćét́úŕ ŕíd́íćúĺúś ḿúś. F́úśćé át́ éx́ b́ĺáńd́ít́, ćόńv́áĺĺíś q́úáḿ ét́, v́úĺṕút́át́é ĺáćúś. + Śúśṕéńd́íśśé śít́ áḿét́ áŕćú út́ áŕćú f́áúćíb́úś v́áŕíúś. V́ív́áḿúś śít́ áḿét́ ḿáx́íḿúś d́íáḿ. Ńáḿ éx́ ĺéό, ṕh́áŕét́ŕá éú ĺόb́όŕt́íś át́, t́ŕíśt́íq́úé út́ f́éĺíś. + """; + + int[] lengths = [1, 10, 100, textSource.Length / 2, textSource.Length]; + + foreach (int length in lengths) + { + yield return textSource [..length]; + } + + string textLongerThanStackallocThreshold = string.Concat(Enumerable.Repeat(textSource, 10)); + yield return textLongerThanStackallocThreshold; + } } diff --git a/Terminal.Gui/Text/StringExtensions.cs b/Terminal.Gui/Text/StringExtensions.cs index 4ad58912b..a40143af8 100644 --- a/Terminal.Gui/Text/StringExtensions.cs +++ b/Terminal.Gui/Text/StringExtensions.cs @@ -124,13 +124,43 @@ public static class StringExtensions /// public static string ToString (IEnumerable runes) { - StringBuilder stringBuilder = new(); const int maxCharsPerRune = 2; - Span charBuffer = stackalloc char[maxCharsPerRune]; + // Max stackalloc ~2 kB + const int maxStackallocTextBufferSize = 1048; + + Span runeBuffer = stackalloc char[maxCharsPerRune]; + // Use stackalloc buffer if rune count is easily available and the count is reasonable. + if (runes.TryGetNonEnumeratedCount (out int count)) + { + if (count == 0) + { + return string.Empty; + } + + int maxRequiredTextBufferSize = count * maxCharsPerRune; + if (maxRequiredTextBufferSize <= maxStackallocTextBufferSize) + { + Span textBuffer = stackalloc char[maxRequiredTextBufferSize]; + Span remainingBuffer = textBuffer; + foreach (Rune rune in runes) + { + int charsWritten = rune.EncodeToUtf16 (runeBuffer); + ReadOnlySpan runeChars = runeBuffer [..charsWritten]; + runeChars.CopyTo (remainingBuffer); + remainingBuffer = remainingBuffer [runeChars.Length..]; + } + + ReadOnlySpan text = textBuffer[..^remainingBuffer.Length]; + return text.ToString (); + } + } + + // Fallback to StringBuilder append. + StringBuilder stringBuilder = new(); foreach (Rune rune in runes) { - int charsWritten = rune.EncodeToUtf16 (charBuffer); - ReadOnlySpan runeChars = charBuffer [..charsWritten]; + int charsWritten = rune.EncodeToUtf16 (runeBuffer); + ReadOnlySpan runeChars = runeBuffer [..charsWritten]; stringBuilder.Append (runeChars); } return stringBuilder.ToString ();