perf: preallocate the slice if we know its final length (#487)

cmd/badges/main.go

@@ -5,8 +5,6 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"github.com/boyter/scc/v3/processor"
-	"github.com/rs/zerolog/log"
 	"math"
 	"net/http"
 	"net/url"
@@ -16,6 +14,9 @@ import (
 	"strconv"
 	"strings"
 	"time"
+
+	"github.com/boyter/scc/v3/processor"
+	"github.com/rs/zerolog/log"
 )
 
 var uniqueCode = "unique_code"
@@ -299,7 +300,7 @@ func processPath(s string) string {
 		return ""
 	}
 
-	sp := []string{}
+	sp := make([]string, 0, len(split))
 
 	for _, s := range split {
 		sp = append(sp, cleanString(s))

main.go

@@ -27,7 +27,7 @@ func main() {
 		}
 
 		args := strings.Split(string(b), "\n")
-		var newArgs []string
+		newArgs := make([]string, 0, len(args))
 		for _, x := range args {
 			newArgs = append(newArgs, strings.TrimSpace(x))
 		}

processor/detector.go

@@ -175,7 +175,7 @@ func DetermineLanguage(filename string, fallbackLanguage string, possibleLanguag
 
 	primary := ""
 
-	toSort := []languageGuess{}
+	toSort := make([]languageGuess, 0, len(possibleLanguages))
 	for _, lan := range possibleLanguages {
 		LanguageFeaturesMutex.Lock()
 		langFeatures := LanguageFeatures[lan]

processor/formatters.go

@@ -297,7 +297,7 @@ func toCSVSummary(input chan *FileJob) string {
 	language := aggregateLanguageSummary(input)
 	language = sortLanguageSummary(language)
 
-	records := [][]string{}
+	records := make([][]string, 0, len(language))
 
 	for _, result := range language {
 		records = append(records, []string{
@@ -606,7 +606,7 @@ func toHtmlTable(input chan *FileJob) string {
 		}
 	}
 
-	language := []LanguageSummary{}
+	language := make([]LanguageSummary, 0, len(languages))
 	for _, summary := range languages {
 		language = append(language, summary)
 	}
@@ -958,7 +958,7 @@ func fileSummarizeLong(input chan *FileJob) string {
 		}
 	}
 
-	language := []LanguageSummary{}
+	language := make([]LanguageSummary, 0, len(langs))
 	for _, summary := range langs {
 		language = append(language, summary)
 	}
@@ -1174,7 +1174,7 @@ func fileSummarizeShort(input chan *FileJob) string {
 		}
 	}
 
-	language := []LanguageSummary{}
+	language := make([]LanguageSummary, 0, len(lang))
 	for _, summary := range lang {
 		language = append(language, summary)
 	}
@@ -1488,7 +1488,7 @@ func aggregateLanguageSummary(input chan *FileJob) []LanguageSummary {
 		}
 	}
 
-	language := []LanguageSummary{}
+	language := make([]LanguageSummary, 0, len(languages))
 	for _, summary := range languages {
 		language = append(language, summary)
 	}

processor/processor.go

@@ -310,7 +310,7 @@ func ProcessConstants() {
 	}
 
 	// Fix for https://github.com/boyter/scc/issues/250
-	fixedPath := []string{}
+	fixedPath := make([]string, 0, len(PathDenyList))
 	for _, path := range PathDenyList {
 		fixedPath = append(fixedPath, strings.TrimRight(path, "/"))
 	}
@@ -532,8 +532,8 @@ func loadDatabase() map[string]Language {
 
 func printLanguages() {
 	database := loadDatabase()
-	var names []string
 
+	names := make([]string, 0, len(database))
 	for key := range database {
 		names = append(names, key)
 	}