Improve search performance by pre-calculating character classes

This simple optmization can give more than 15% performance boost
in some scenarios.

3 files changed, 28 insertions, 21 deletions

diff --git a/src/algo/algo.go b/src/algo/algo.go
index 5cb82bdd..6e0d437c 100644
--- a/src/algo/algo.go
+++ b/src/algo/algo.go
@@ -153,6 +153,9 @@ var (
 	bonusBoundaryDelimiter int16 = bonusBoundary + 1
 
 	initialCharClass charClass = charWhite
+
+	// A minor optimization that can give 15%+ performance boost
+	asciiCharClasses [unicode.MaxASCII + 1]charClass
 )
 
 type charClass int
@@ -187,6 +190,22 @@ func Init(scheme string) bool {
 	default:
 		return false
 	}
+	for i := 0; i <= unicode.MaxASCII; i++ {
+		char := rune(i)
+		c := charNonWord
+		if char >= 'a' && char <= 'z' {
+			c = charLower
+		} else if char >= 'A' && char <= 'Z' {
+			c = charUpper
+		} else if char >= '0' && char <= '9' {
+			c = charNumber
+		} else if strings.ContainsRune(whiteChars, char) {
+			c = charWhite
+		} else if strings.ContainsRune(delimiterChars, char) {
+			c = charDelimiter
+		}
+		asciiCharClasses[i] = c
+	}
 	return true
 }
 
@@ -214,21 +233,6 @@ func alloc32(offset int, slab *util.Slab, size int) (int, []int32) {
 	return offset, make([]int32, size)
 }
 
-func charClassOfAscii(char rune) charClass {
-	if char >= 'a' && char <= 'z' {
-		return charLower
-	} else if char >= 'A' && char <= 'Z' {
-		return charUpper
-	} else if char >= '0' && char <= '9' {
-		return charNumber
-	} else if strings.ContainsRune(whiteChars, char) {
-		return charWhite
-	} else if strings.ContainsRune(delimiterChars, char) {
-		return charDelimiter
-	}
-	return charNonWord
-}
-
 func charClassOfNonAscii(char rune) charClass {
 	if unicode.IsLower(char) {
 		return charLower
@@ -248,7 +252,7 @@ func charClassOfNonAscii(char rune) charClass {
 
 func charClassOf(char rune) charClass {
 	if char <= unicode.MaxASCII {
-		return charClassOfAscii(char)
+		return asciiCharClasses[char]
 	}
 	return charClassOfNonAscii(char)
 }
@@ -447,9 +451,10 @@ func FuzzyMatchV2(caseSensitive bool, normalize bool, forward bool, input *util.
 	for off, char := range Tsub {
 		var class charClass
 		if char <= unicode.MaxASCII {
-			class = charClassOfAscii(char)
+			class = asciiCharClasses[char]
 			if !caseSensitive && class == charUpper {
 				char += 32
+				Tsub[off] = char
 			}
 		} else {
 			class = charClassOfNonAscii(char)
@@ -459,9 +464,9 @@ func FuzzyMatchV2(caseSensitive bool, normalize bool, forward bool, input *util.
 			if normalize {
 				char = normalizeRune(char)
 			}
+			Tsub[off] = char
 		}
 
-		Tsub[off] = char
 		bonus := bonusFor(prevClass, class)
 		Bsub[off] = bonus
 		prevClass = class
diff --git a/src/algo/algo_test.go b/src/algo/algo_test.go
index a7c4e1d3..b5ed0e77 100644
--- a/src/algo/algo_test.go
+++ b/src/algo/algo_test.go
@@ -9,6 +9,10 @@ import (
 	"github.com/junegunn/fzf/src/util"
 )
 
+func init() {
+	Init("default")
+}
+
 func assertMatch(t *testing.T, fun Algo, caseSensitive, forward bool, input, pattern string, sidx int, eidx int, score int) {
 	assertMatch2(t, fun, caseSensitive, false, forward, input, pattern, sidx, eidx, score)
 }
diff --git a/src/options.go b/src/options.go
index 76fe9ee9..38a5ba7c 100644
--- a/src/options.go
+++ b/src/options.go
@@ -2259,9 +2259,7 @@ func postProcessOptions(opts *Options) {
 		theme.Spinner = boldify(theme.Spinner)
 	}
 
-	if opts.Scheme != "default" {
-		processScheme(opts)
-	}
+	processScheme(opts)
 }
 
 func expectsArbitraryString(opt string) bool {