strings: add function to reverse a string

2 files changed, 31 insertions, 0 deletions

diff --git a/lib/strings/string.go b/lib/strings/string.go
index 491edd7f..69e63893 100644
--- a/lib/strings/string.go
+++ b/lib/strings/string.go
@@ -164,6 +164,21 @@ func MergeSpaces(text string, withline bool) string {
 }
 
 //
+// Reverse the string.
+//
+func Reverse(input string) string {
+	r := []rune(input)
+	x := 0
+	y := len(r) - 1
+	for x < len(r)/2 {
+		r[x], r[y] = r[y], r[x]
+		x += 1
+		y -= 1
+	}
+	return string(r)
+}
+
+//
 // Split given a text, return all words in text.
 //
 // A word is any sequence of character which have length equal or greater than
diff --git a/lib/strings/string_test.go b/lib/strings/string_test.go
index 0afdcdf5..11644de8 100644
--- a/lib/strings/string_test.go
+++ b/lib/strings/string_test.go
@@ -169,6 +169,22 @@ func TestMergeSpaces(t *testing.T) {
 	}
 }
 
+func TestReverse(t *testing.T) {
+	cases := []struct {
+		input string
+		exp   string
+	}{{
+		input: "The quick bròwn 狐 jumped over the lazy 犬",
+		exp:   "犬 yzal eht revo depmuj 狐 nwòrb kciuq ehT",
+	}}
+
+	for _, c := range cases {
+		got := Reverse(c.input)
+
+		test.Assert(t, "Reverse", c.exp, got, true)
+	}
+}
+
 func TestSplit(t *testing.T) {
 	cases := []struct {
 		text string