perf: Improve performance of ansistyles.

pkg/ansistyles/ansistyle_benchmark_test.go

@@ -0,0 +1,19 @@
+package ansistyles
+
+import (
+	"testing"
+)
+
+func BenchmarkAnsi(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		Ansi(7)
+	}
+}
+
+func BenchmarkAnsi16m(b *testing.B) {
+	b.ReportAllocs()
+	for i := 0; i < b.N; i++ {
+		Ansi16m(10, 30, 255)
+	}
+}

pkg/ansistyles/ansistyles.go

@@ -102,6 +102,7 @@ import (
 	"fmt"
 	"math"
 	"regexp"
+	"strconv"
 )
 
 // CSPair contains the ANSI color codes to open and close a given color.
@@ -122,38 +123,44 @@ func namedCSPair(open uint8, close uint8) CSPair {
 //
 // `color` should be a number between 30 and 37 or 90 and 97, inclusive.
 func Ansi(color uint8) string {
-	return fmt.Sprintf("\u001B[%dm", color)
+	return "\u001B[" + strconv.FormatUint(uint64(color), 10) + "m"
 }
 
 // BgAnsi returns the string used to set the background color, based on a basic 16-color Ansi code.
 //
 // `color` should be a number between 30 and 37 or 90 and 97, inclusive.
 func BgAnsi(color uint8) string {
-	return fmt.Sprintf("\u001B[%dm", color+10)
+	return "\u001B[" + strconv.FormatUint(uint64(color+10), 10) + "m"
 }
 
 // Ansi256 returns the string used to set the foreground color, based on Ansi 256 color lookup table.
 //
 // See https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit.
 func Ansi256(color uint8) string {
-	return fmt.Sprintf("\u001B[38;5;%dm", color)
+	return "\u001B[38;5;" + strconv.FormatUint(uint64(color), 10) + "m"
 }
 
 // BgAnsi256 returns the string used to set the background color, based on Ansi 256 color lookup table.
 //
 // See https://en.wikipedia.org/wiki/ANSI_escape_code#8-bit.
 func BgAnsi256(color uint8) string {
-	return fmt.Sprintf("\u001B[48;5;%dm", color)
+	return "\u001B[48;5;" + strconv.FormatUint(uint64(color), 10) + "m"
 }
 
 // Ansi16m returns the string used to set a 24bit foreground color.
 func Ansi16m(red uint8, green uint8, blue uint8) string {
-	return fmt.Sprintf("\u001B[38;2;%v;%v;%vm", red, green, blue)
+	return "\u001B[38;2;" +
+		strconv.FormatUint(uint64(red), 10) + ";" +
+		strconv.FormatUint(uint64(green), 10) + ";" +
+		strconv.FormatUint(uint64(blue), 10) + "m"
 }
 
 // BgAnsi16m returns the string used to set a 24bit background color.
 func BgAnsi16m(red uint8, green uint8, blue uint8) string {
-	return fmt.Sprintf("\u001B[48;2;%v;%v;%vm", red, green, blue)
+	return "\u001B[48;2;" +
+		strconv.FormatUint(uint64(red), 10) + ";" +
+		strconv.FormatUint(uint64(green), 10) + ";" +
+		strconv.FormatUint(uint64(blue), 10) + "m"
 }
 
 // Close is the "close" code for 256 amd 16m ansi color codes.