Avoid unconditionally storsing input as runes

When --with-nth is used, fzf used to preprocess each line and store the
result as rune array, which was wasteful if the line only contains ascii
characters.

9 files changed, 44 insertions, 127 deletions

diff --git a/src/core.go b/src/core.go
index aa425109..3e60934a 100644
--- a/src/core.go
+++ b/src/core.go
@@ -63,9 +63,6 @@ func Run(opts *Options, revision string) {
 	ansiProcessor := func(data []byte) (util.Chars, *[]ansiOffset) {
 		return util.ToChars(data), nil
 	}
-	ansiProcessorRunes := func(data []rune) (util.Chars, *[]ansiOffset) {
-		return util.RunesToChars(data), nil
-	}
 	if opts.Ansi {
 		if opts.Theme != nil {
 			var state *ansiState
@@ -82,9 +79,6 @@ func Run(opts *Options, revision string) {
 				return util.RunesToChars([]rune(trimmed)), nil
 			}
 		}
-		ansiProcessorRunes = func(data []rune) (util.Chars, *[]ansiOffset) {
-			return ansiProcessor([]byte(string(data)))
-		}
 	}
 
 	// Chunk list
@@ -103,15 +97,15 @@ func Run(opts *Options, revision string) {
 		})
 	} else {
 		chunkList = NewChunkList(func(data []byte, index int) Item {
-			tokens := Tokenize(util.ToChars(data), opts.Delimiter)
+			tokens := Tokenize(string(data), opts.Delimiter)
 			trans := Transform(tokens, opts.WithNth)
+			transformed := joinTokens(trans)
 			if len(header) < opts.HeaderLines {
-				header = append(header, string(joinTokens(trans)))
+				header = append(header, transformed)
 				eventBox.Set(EvtHeader, header)
 				return nilItem
 			}
-			textRunes := joinTokens(trans)
-			trimmed, colors := ansiProcessorRunes(textRunes)
+			trimmed, colors := ansiProcessor([]byte(transformed))
 			trimmed.Index = int32(index)
 			return Item{text: trimmed, colors: colors, origText: &data}
 		})
diff --git a/src/options_test.go b/src/options_test.go
index 907faf03..d3c93450 100644
--- a/src/options_test.go
+++ b/src/options_test.go
@@ -6,7 +6,6 @@ import (
 	"testing"
 
 	"github.com/junegunn/fzf/src/tui"
-	"github.com/junegunn/fzf/src/util"
 )
 
 func TestDelimiterRegex(t *testing.T) {
@@ -44,7 +43,7 @@ func TestDelimiterRegex(t *testing.T) {
 
 func TestDelimiterRegexString(t *testing.T) {
 	delim := delimiterRegexp("*")
-	tokens := Tokenize(util.RunesToChars([]rune("-*--*---**---")), delim)
+	tokens := Tokenize("-*--*---**---", delim)
 	if delim.regex != nil ||
 		tokens[0].text.ToString() != "-*" ||
 		tokens[1].text.ToString() != "--*" ||
@@ -57,7 +56,7 @@ func TestDelimiterRegexString(t *testing.T) {
 
 func TestDelimiterRegexRegex(t *testing.T) {
 	delim := delimiterRegexp("--\\*")
-	tokens := Tokenize(util.RunesToChars([]rune("-*--*---**---")), delim)
+	tokens := Tokenize("-*--*---**---", delim)
 	if delim.str != nil ||
 		tokens[0].text.ToString() != "-*--*" ||
 		tokens[1].text.ToString() != "---*" ||
diff --git a/src/pattern.go b/src/pattern.go
index 97ee8fd6..64296d71 100644
--- a/src/pattern.go
+++ b/src/pattern.go
@@ -362,7 +362,7 @@ func (p *Pattern) prepareInput(item *Item) []Token {
 		return *item.transformed
 	}
 
-	tokens := Tokenize(item.text, p.delimiter)
+	tokens := Tokenize(item.text.ToString(), p.delimiter)
 	ret := Transform(tokens, p.nth)
 	item.transformed = &ret
 	return ret
diff --git a/src/pattern_test.go b/src/pattern_test.go
index 31a127e3..85c174c9 100644
--- a/src/pattern_test.go
+++ b/src/pattern_test.go
@@ -133,7 +133,7 @@ func TestCaseSensitivity(t *testing.T) {
 
 func TestOrigTextAndTransformed(t *testing.T) {
 	pattern := BuildPattern(true, algo.FuzzyMatchV2, true, CaseSmart, false, true, true, []Range{}, Delimiter{}, []rune("jg"))
-	tokens := Tokenize(util.RunesToChars([]rune("junegunn")), Delimiter{})
+	tokens := Tokenize("junegunn", Delimiter{})
 	trans := Transform(tokens, []Range{Range{1, 1}})
 
 	origBytes := []byte("junegunn.choi")
diff --git a/src/terminal.go b/src/terminal.go
index 81fb8808..8d0b6bf8 100644
--- a/src/terminal.go
+++ b/src/terminal.go
@@ -1174,7 +1174,7 @@ func replacePlaceholder(template string, stripAnsi bool, delimiter Delimiter, fo
 
 		for idx, item := range items {
 			chars := util.RunesToChars([]rune(item.AsString(stripAnsi)))
-			tokens := Tokenize(chars, delimiter)
+			tokens := Tokenize(chars.ToString(), delimiter)
 			trans := Transform(tokens, ranges)
 			str := string(joinTokens(trans))
 			if delimiter.str != nil {
diff --git a/src/tokenizer.go b/src/tokenizer.go
index 0e216ac7..5b7a8b6f 100644
--- a/src/tokenizer.go
+++ b/src/tokenizer.go
@@ -1,6 +1,7 @@
 package fzf
 
 import (
+	"bytes"
 	"regexp"
 	"strconv"
 	"strings"
@@ -74,14 +75,14 @@ func ParseRange(str *string) (Range, bool) {
 	return newRange(n, n), true
 }
 
-func withPrefixLengths(tokens []util.Chars, begin int) []Token {
+func withPrefixLengths(tokens []string, begin int) []Token {
 	ret := make([]Token, len(tokens))
 
 	prefixLength := begin
-	for idx, token := range tokens {
-		// NOTE: &tokens[idx] instead of &tokens
-		ret[idx] = Token{&tokens[idx], int32(prefixLength)}
-		prefixLength += token.Length()
+	for idx := range tokens {
+		chars := util.ToChars([]byte(tokens[idx]))
+		ret[idx] = Token{&chars, int32(prefixLength)}
+		prefixLength += chars.Length()
 	}
 	return ret
 }
@@ -92,16 +93,15 @@ const (
 	awkWhite
 )
 
-func awkTokenizer(input util.Chars) ([]util.Chars, int) {
+func awkTokenizer(input string) ([]string, int) {
 	// 9, 32
-	ret := []util.Chars{}
+	ret := []string{}
 	prefixLength := 0
 	state := awkNil
-	numChars := input.Length()
 	begin := 0
 	end := 0
-	for idx := 0; idx < numChars; idx++ {
-		r := input.Get(idx)
+	for idx := 0; idx < len(input); idx++ {
+		r := input[idx]
 		white := r == 9 || r == 32
 		switch state {
 		case awkNil:
@@ -119,19 +119,19 @@ func awkTokenizer(input util.Chars) ([]util.Chars, int) {
 			if white {
 				end = idx + 1
 			} else {
-				ret = append(ret, input.Slice(begin, end))
+				ret = append(ret, input[begin:end])
 				state, begin, end = awkBlack, idx, idx+1
 			}
 		}
 	}
 	if begin < end {
-		ret = append(ret, input.Slice(begin, end))
+		ret = append(ret, input[begin:end])
 	}
 	return ret, prefixLength
 }
 
 // Tokenize tokenizes the given string with the delimiter
-func Tokenize(text util.Chars, delimiter Delimiter) []Token {
+func Tokenize(text string, delimiter Delimiter) []Token {
 	if delimiter.str == nil && delimiter.regex == nil {
 		// AWK-style (\S+\s*)
 		tokens, prefixLength := awkTokenizer(text)
@@ -139,36 +139,31 @@ func Tokenize(text util.Chars, delimiter Delimiter) []Token {
 	}
 
 	if delimiter.str != nil {
-		return withPrefixLengths(text.Split(*delimiter.str), 0)
+		return withPrefixLengths(strings.SplitAfter(text, *delimiter.str), 0)
 	}
 
 	// FIXME performance
 	var tokens []string
 	if delimiter.regex != nil {
-		str := text.ToString()
-		for len(str) > 0 {
-			loc := delimiter.regex.FindStringIndex(str)
+		for len(text) > 0 {
+			loc := delimiter.regex.FindStringIndex(text)
 			if loc == nil {
-				loc = []int{0, len(str)}
+				loc = []int{0, len(text)}
 			}
 			last := util.Max(loc[1], 1)
-			tokens = append(tokens, str[:last])
-			str = str[last:]
+			tokens = append(tokens, text[:last])
+			text = text[last:]
 		}
 	}
-	asRunes := make([]util.Chars, len(tokens))
-	for i, token := range tokens {
-		asRunes[i] = util.RunesToChars([]rune(token))
-	}
-	return withPrefixLengths(asRunes, 0)
+	return withPrefixLengths(tokens, 0)
 }
 
-func joinTokens(tokens []Token) []rune {
-	ret := []rune{}
+func joinTokens(tokens []Token) string {
+	var output bytes.Buffer
 	for _, token := range tokens {
-		ret = append(ret, token.text.ToRunes()...)
+		output.WriteString(token.text.ToString())
 	}
-	return ret
+	return output.String()
 }
 
 // Transform is used to transform the input when --with-nth option is given
@@ -181,7 +176,7 @@ func Transform(tokens []Token, withNth []Range) []Token {
 		if r.begin == r.end {
 			idx := r.begin
 			if idx == rangeEllipsis {
-				chars := util.RunesToChars(joinTokens(tokens))
+				chars := util.ToChars([]byte(joinTokens(tokens)))
 				parts = append(parts, &chars)
 			} else {
 				if idx < 0 {
@@ -224,15 +219,15 @@ func Transform(tokens []Token, withNth []Range) []Token {
 		var merged util.Chars
 		switch len(parts) {
 		case 0:
-			merged = util.RunesToChars([]rune{})
+			merged = util.ToChars([]byte{})
 		case 1:
 			merged = *parts[0]
 		default:
-			runes := []rune{}
+			var output bytes.Buffer
 			for _, part := range parts {
-				runes = append(runes, part.ToRunes()...)
+				output.WriteString(part.ToString())
 			}
-			merged = util.RunesToChars(runes)
+			merged = util.ToChars([]byte(output.String()))
 		}
 
 		var prefixLength int32
diff --git a/src/tokenizer_test.go b/src/tokenizer_test.go
index 59250906..110fd062 100644
--- a/src/tokenizer_test.go
+++ b/src/tokenizer_test.go
@@ -2,8 +2,6 @@ package fzf
 
 import (
 	"testing"
-
-	"github.com/junegunn/fzf/src/util"
 )
 
 func TestParseRange(t *testing.T) {
@@ -47,19 +45,19 @@ func TestParseRange(t *testing.T) {
 func TestTokenize(t *testing.T) {
 	// AWK-style
 	input := "  abc:  def:  ghi  "
-	tokens := Tokenize(util.RunesToChars([]rune(input)), Delimiter{})
+	tokens := Tokenize(input, Delimiter{})
 	if tokens[0].text.ToString() != "abc:  " || tokens[0].prefixLength != 2 {
 		t.Errorf("%s", tokens)
 	}
 
 	// With delimiter
-	tokens = Tokenize(util.RunesToChars([]rune(input)), delimiterRegexp(":"))
+	tokens = Tokenize(input, delimiterRegexp(":"))
 	if tokens[0].text.ToString() != "  abc:" || tokens[0].prefixLength != 0 {
-		t.Errorf("%s", tokens)
+		t.Error(tokens[0].text.ToString(), tokens[0].prefixLength)
 	}
 
 	// With delimiter regex
-	tokens = Tokenize(util.RunesToChars([]rune(input)), delimiterRegexp("\\s+"))
+	tokens = Tokenize(input, delimiterRegexp("\\s+"))
 	if tokens[0].text.ToString() != "  " || tokens[0].prefixLength != 0 ||
 		tokens[1].text.ToString() != "abc:  " || tokens[1].prefixLength != 2 ||
 		tokens[2].text.ToString() != "def:  " || tokens[2].prefixLength != 8 ||
@@ -71,7 +69,7 @@ func TestTokenize(t *testing.T) {
 func TestTransform(t *testing.T) {
 	input := "  abc:  def:  ghi:  jkl"
 	{
-		tokens := Tokenize(util.RunesToChars([]rune(input)), Delimiter{})
+		tokens := Tokenize(input, Delimiter{})
 		{
 			ranges := splitNth("1,2,3")
 			tx := Transform(tokens, ranges)
@@ -93,7 +91,7 @@ func TestTransform(t *testing.T) {
 		}
 	}
 	{
-		tokens := Tokenize(util.RunesToChars([]rune(input)), delimiterRegexp(":"))
+		tokens := Tokenize(input, delimiterRegexp(":"))
 		{
 			ranges := splitNth("1..2,3,2..,1")
 			tx := Transform(tokens, ranges)
diff --git a/src/util/chars.go b/src/util/chars.go
index 5e702004..61e93411 100644
--- a/src/util/chars.go
+++ b/src/util/chars.go
@@ -157,46 +157,3 @@ func (chars *Chars) CopyRunes(dest []rune) {
 	}
 	return
 }
-
-func (chars *Chars) Slice(b int, e int) Chars {
-	if runes := chars.optionalRunes(); runes != nil {
-		return RunesToChars(runes[b:e])
-	}
-	return Chars{slice: chars.slice[b:e], inBytes: true}
-}
-
-func (chars *Chars) Split(delimiter string) []Chars {
-	delim := []rune(delimiter)
-	numChars := chars.Length()
-	numDelim := len(delim)
-	begin := 0
-	ret := make([]Chars, 0, 1)
-
-	for index := 0; index < numChars; {
-		if index+numDelim <= numChars {
-			match := true
-			for off, d := range delim {
-				if chars.Get(index+off) != d {
-					match = false
-					break
-				}
-			}
-			// Found the delimiter
-			if match {
-				incr := Max(numDelim, 1)
-				ret = append(ret, chars.Slice(begin, index+incr))
-				index += incr
-				begin = index
-				continue
-			}
-		} else {
-			// Impossible to find the delimiter in the remaining substring
-			break
-		}
-		index++
-	}
-	if begin < numChars || len(ret) == 0 {
-		ret = append(ret, chars.Slice(begin, numChars))
-	}
-	return ret
-}
diff --git a/src/util/chars_test.go b/src/util/chars_test.go
index 07b8dea5..b7983f30 100644
--- a/src/util/chars_test.go
+++ b/src/util/chars_test.go
@@ -44,29 +44,3 @@ func TestTrimLength(t *testing.T) {
 	check("  h   o  ", 5)
 	check("         ", 0)
 }
-
-func TestSplit(t *testing.T) {
-	check := func(str string, delim string, tokens ...string) {
-		input := ToChars([]byte(str))
-		result := input.Split(delim)
-		if len(result) != len(tokens) {
-			t.Errorf(
-				"Invalid Split result for '%s': %d tokens found (expected %d): %s",
-				str, len(result), len(tokens), result)
-		}
-		for idx, token := range tokens {
-			if result[idx].ToString() != token {
-				t.Errorf("Invalid Split result for '%s': %s (expected %s)",
-					str, result[idx].ToString(), token)
-			}
-		}
-	}
-	check("abc:def::", ":", "abc:", "def:", ":")
-	check("abc:def::", "-", "abc:def::")
-	check("abc", "", "a", "b", "c")
-	check("abc", "a", "a", "bc")
-	check("abc", "ab", "ab", "c")
-	check("abc", "abc", "abc")
-	check("abc", "abcd", "abc")
-	check("", "abcd", "")
-}