[perf] Avoid allocating rune array for ascii string

In the best case (all ascii), this reduces the memory footprint by 60%
and the response time by 15% to 20%. In the worst case (every line has
non-ascii characters), 3 to 4% overhead is observed.

src/util/util.go

@@ -7,7 +7,6 @@ import (
 	"os"
 	"os/exec"
 	"time"
-	"unicode/utf8"
 )
 
 // Max returns the largest integer
@@ -84,34 +83,6 @@ func IsTty() bool {
 	return int(C.isatty(C.int(os.Stdin.Fd()))) != 0
 }
 
-// TrimRight returns rune array with trailing white spaces cut off
-func TrimRight(runes []rune) []rune {
-	var i int
-	for i = len(runes) - 1; i >= 0; i-- {
-		char := runes[i]
-		if char != ' ' && char != '\t' {
-			break
-		}
-	}
-	return runes[0 : i+1]
-}
-
-// BytesToRunes converts byte array into rune array
-func BytesToRunes(bytea []byte) []rune {
-	runes := make([]rune, 0, len(bytea))
-	for i := 0; i < len(bytea); {
-		if bytea[i] < utf8.RuneSelf {
-			runes = append(runes, rune(bytea[i]))
-			i++
-		} else {
-			r, sz := utf8.DecodeRune(bytea[i:])
-			i += sz
-			runes = append(runes, r)
-		}
-	}
-	return runes
-}
-
 // TrimLen returns the length of trimmed rune array
 func TrimLen(runes []rune) int {
 	var i int