init

internal/counter/counter.go

@@ -0,0 +1,53 @@
+package counter
+
+import (
+	"bufio"
+	"io"
+	"sort"
+)
+
+const maxLineSize = 1024 * 1024
+
+type Result struct {
+	Name  string
+	Count int
+}
+
+func Count(r io.Reader) (map[string]int, error) {
+	counts := make(map[string]int)
+
+	scanner := bufio.NewScanner(r)
+	scanner.Buffer(make([]byte, 64*1024), maxLineSize)
+
+	for scanner.Scan() {
+		name := scanner.Text()
+		if name == "" {
+			continue
+		}
+
+		counts[name]++
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return counts, nil
+}
+
+func Sorted(counts map[string]int) []Result {
+	results := make([]Result, 0, len(counts))
+	for name, count := range counts {
+		results = append(results, Result{Name: name, Count: count})
+	}
+
+	sort.Slice(results, func(i, j int) bool {
+		if results[i].Count != results[j].Count {
+			return results[i].Count > results[j].Count
+		}
+
+		return results[i].Name < results[j].Name
+	})
+
+	return results
+}