1 files changed, 26 insertions, 32 deletions

diff --git a/src/terminal.go b/src/terminal.go
index 54f96675..aabeb07c 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -2,7 +2,6 @@ package fzf
 
 import (
 	"bufio"
-	"bytes"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -15,6 +14,9 @@ import (
 	"syscall"
 	"time"
 
+	"github.com/mattn/go-runewidth"
+	"github.com/rivo/uniseg"
+
 	"github.com/junegunn/fzf/src/tui"
 	"github.com/junegunn/fzf/src/util"
 )
@@ -673,11 +675,8 @@ func (t *Terminal) sortSelected() []selectedItem {
 }
 
 func (t *Terminal) displayWidth(runes []rune) int {
-	l := 0
-	for _, r := range runes {
-		l += util.RuneWidth(r, l, t.tabstop)
-	}
-	return l
+	width, _ := util.RunesWidth(runes, 0, t.tabstop, 0)
+	return width
 }
 
 const (
@@ -1141,28 +1140,18 @@ func (t *Terminal) printItem(result Result, line int, i int, current bool) {
 	t.prevLines[i] = newLine
 }
 
-func (t *Terminal) trimRight(runes []rune, width int) ([]rune, int) {
+func (t *Terminal) trimRight(runes []rune, width int) ([]rune, bool) {
 	// We start from the beginning to handle tab characters
-	l := 0
-	for idx, r := range runes {
-		l += util.RuneWidth(r, l, t.tabstop)
-		if l > width {
-			return runes[:idx], len(runes) - idx
-		}
+	width, overflowIdx := util.RunesWidth(runes, 0, t.tabstop, width)
+	if overflowIdx >= 0 {
+		return runes[:overflowIdx], true
 	}
-	return runes, 0
+	return runes, false
 }
 
 func (t *Terminal) displayWidthWithLimit(runes []rune, prefixWidth int, limit int) int {
-	l := 0
-	for _, r := range runes {
-		l += util.RuneWidth(r, l+prefixWidth, t.tabstop)
-		if l > limit {
-			// Early exit
-			return l
-		}
-	}
-	return l
+	width, _ := util.RunesWidth(runes, prefixWidth, t.tabstop, limit)
+	return width
 }
 
 func (t *Terminal) trimLeft(runes []rune, width int) ([]rune, int32) {
@@ -1362,9 +1351,9 @@ func (t *Terminal) renderPreviewText(height int, lines []string, lineNo int, unc
 			prefixWidth := 0
 			_, _, ansi = extractColor(line, ansi, func(str string, ansi *ansiState) bool {
 				trimmed := []rune(str)
-				trimmedLen := 0
+				isTrimmed := false
 				if !t.previewOpts.wrap {
-					trimmed, trimmedLen = t.trimRight(trimmed, maxWidth-t.pwindow.X())
+					trimmed, isTrimmed = t.trimRight(trimmed, maxWidth-t.pwindow.X())
 				}
 				str, width := t.processTabs(trimmed, prefixWidth)
 				prefixWidth += width
@@ -1374,7 +1363,7 @@ func (t *Terminal) renderPreviewText(height int, lines []string, lineNo int, unc
 				} else {
 					fillRet = t.pwindow.CFill(tui.ColPreview.Fg(), tui.ColPreview.Bg(), tui.AttrRegular, str)
 				}
-				return trimmedLen == 0 &&
+				return !isTrimmed &&
 					(fillRet == tui.FillContinue || t.previewOpts.wrap && fillRet == tui.FillNextLine)
 			})
 			t.previewer.scrollable = t.previewer.scrollable || t.pwindow.Y() == height-1 && t.pwindow.X() == t.pwindow.Width()
@@ -1430,16 +1419,21 @@ func (t *Terminal) printPreviewDelayed() {
 }
 
 func (t *Terminal) processTabs(runes []rune, prefixWidth int) (string, int) {
-	var strbuf bytes.Buffer
+	var strbuf strings.Builder
 	l := prefixWidth
-	for _, r := range runes {
-		w := util.RuneWidth(r, l, t.tabstop)
-		l += w
-		if r == '\t' {
+	gr := uniseg.NewGraphemes(string(runes))
+	for gr.Next() {
+		rs := gr.Runes()
+		str := string(rs)
+		var w int
+		if len(rs) == 1 && rs[0] == '\t' {
+			w = t.tabstop - l%t.tabstop
 			strbuf.WriteString(strings.Repeat(" ", w))
 		} else {
-			strbuf.WriteRune(r)
+			w = runewidth.StringWidth(str)
+			strbuf.WriteString(str)
 		}
+		l += w
 	}
 	return strbuf.String(), l
 }