Minor optimizations

cmd/micro/actions.go

@@ -7,6 +7,7 @@ import (
 	"strconv"
 	"strings"
 	"time"
+	"unicode/utf8"
 
 	"github.com/yuin/gopher-lua"
 	"github.com/zyedidia/clipboard"
@@ -742,9 +743,9 @@ func (v *View) Backspace(usePlugin bool) bool {
 		// If the user is using spaces instead of tabs and they are deleting
 		// whitespace at the start of the line, we should delete as if it's a
 		// tab (tabSize number of spaces)
-		lineStart := v.Buf.Line(v.Cursor.Y)[:v.Cursor.X]
+		lineStart := sliceEnd(v.Buf.LineBytes(v.Cursor.Y), v.Cursor.X)
 		tabSize := int(v.Buf.Settings["tabsize"].(float64))
-		if v.Buf.Settings["tabstospaces"].(bool) && IsSpaces(lineStart) && len(lineStart) != 0 && len(lineStart)%tabSize == 0 {
+		if v.Buf.Settings["tabstospaces"].(bool) && IsSpaces(lineStart) && utf8.RuneCount(lineStart) != 0 && utf8.RuneCount(lineStart)%tabSize == 0 {
 			loc := v.Cursor.Loc
 			v.Buf.Remove(loc.Move(-tabSize, v.Buf), loc)
 		} else {

cmd/micro/cellview.go

@@ -85,7 +85,7 @@ func (c *CellView) Draw(buf *Buffer, top, height, left, width int) {
 	indentrunes := []rune(buf.Settings["indentchar"].(string))
 	// if empty indentchar settings, use space
 	if indentrunes == nil || len(indentrunes) == 0 {
-		indentrunes = []rune(" ")
+		indentrunes = []rune{' '}
 	}
 	indentchar := indentrunes[0]
 

cmd/micro/command.go

@@ -176,7 +176,7 @@ func PluginCmd(args []string) {
 					continue
 				}
 			}
-			if !IsSpaces(removed) {
+			if !IsSpaces([]byte(removed)) {
 				messenger.Message("Removed ", removed)
 			} else {
 				messenger.Error("The requested plugins do not exist")

cmd/micro/lineArray.go

@@ -89,7 +89,6 @@ func NewLineArray(size int64, reader io.Reader) *LineArray {
 		if n >= 1000 && loaded >= 0 {
 			totalLinesNum := int(float64(size) * (float64(n) / float64(loaded)))
 			newSlice := make([]Line, len(la.lines), totalLinesNum+10000)
-			// The copy function is predeclared and works for any slice type.
 			copy(newSlice, la.lines)
 			la.lines = newSlice
 			loaded = -1
@@ -147,9 +146,9 @@ func (la *LineArray) SaveString(useCrlf bool) string {
 
 // NewlineBelow adds a newline below the given line number
 func (la *LineArray) NewlineBelow(y int) {
-	la.lines = append(la.lines, Line{[]byte(" "), nil, nil, false})
+	la.lines = append(la.lines, Line{[]byte{' '}, nil, nil, false})
 	copy(la.lines[y+2:], la.lines[y+1:])
-	la.lines[y+1] = Line{[]byte(""), la.lines[y].state, nil, false}
+	la.lines[y+1] = Line{[]byte{}, la.lines[y].state, nil, false}
 }
 
 // inserts a byte array at a given location

cmd/micro/util.go

@@ -37,6 +37,40 @@ func toRunes(b []byte) []rune {
 	return runes
 }
 
+func sliceStart(slc []byte, index int) []byte {
+	len := len(slc)
+	i := 0
+	totalSize := 0
+	for totalSize < len {
+		if i >= index {
+			return slc[totalSize:]
+		}
+
+		_, size := utf8.DecodeRune(slc[totalSize:])
+		totalSize += size
+		i++
+	}
+
+	return slc[totalSize:]
+}
+
+func sliceEnd(slc []byte, index int) []byte {
+	len := len(slc)
+	i := 0
+	totalSize := 0
+	for totalSize < len {
+		if i >= index {
+			return slc[:totalSize]
+		}
+
+		_, size := utf8.DecodeRune(slc[totalSize:])
+		totalSize += size
+		i++
+	}
+
+	return slc[:totalSize]
+}
+
 // NumOccurrences counts the number of occurrences of a byte in a string
 func NumOccurrences(s string, c byte) int {
 	var n int
@@ -144,7 +178,7 @@ func GetLeadingWhitespace(str string) string {
 }
 
 // IsSpaces checks if a given string is only spaces
-func IsSpaces(str string) bool {
+func IsSpaces(str []byte) bool {
 	for _, c := range str {
 		if c != ' ' {
 			return false