text: process Carriage-Return codes correctly

table/render_test.go

@@ -620,7 +620,7 @@ func TestTable_Render_CRLF(t *testing.T) {
 	tw := NewWriter()
 	tw.AppendHeader(testHeader)
 	tw.AppendRows(testRows)
-	tw.AppendRow(Row{5000, "Night", "King", 10000, "Was once a\r\nMortal \rMan"})
+	tw.AppendRow(Row{5000, "Night", "King", 10000, "Was once a\r\nMortal \rMen"})
 	tw.AppendFooter(testFooter)
 
 	compareOutput(t, tw.Render(), `
@@ -631,7 +631,7 @@ func TestTable_Render_CRLF(t *testing.T) {
 |   20 | Jon        | Snow      |   2000 | You know nothing, Jon Snow! |
 |  300 | Tyrion     | Lannister |   5000 |                             |
 | 5000 | Night      | King      |  10000 | Was once a                  |
-|      |            |           |        | Man                         |
+|      |            |           |        | Mental                      |
 +------+------------+-----------+--------+-----------------------------+
 |      |            | TOTAL     |  10000 |                             |
 +------+------------+-----------+--------+-----------------------------+`)

text/string.go

@@ -1,7 +1,6 @@
 package text
 
 import (
-	"regexp"
 	"strings"
 	"unicode/utf8"
 
@@ -108,21 +107,38 @@ func Pad(str string, maxLen int, paddingChar rune) string {
 	return str
 }
 
-var (
-	reCarriageReturn = regexp.MustCompile(`(.*)\r`)
-)
-
-// ProcessCRLF converts "\r\n" to "\n", and erases everything preceding a lone
-// "\r" in each line of the string.
+// ProcessCRLF converts "\r\n" to "\n", and processes lone "\r" by moving the
+// cursor/carriage to the start of the line and overwrites the contents
+// accordingly. Ex.:
+//
+// ProcessCRLF("abc") == "abc"
+// ProcessCRLF("abc\r\ndef") == "abc\ndef"
+// ProcessCRLF("abc\r\ndef\rghi") == "abc\nghi"
+// ProcessCRLF("abc\r\ndef\rghi\njkl") == "abc\nghi\njkl"
+// ProcessCRLF("abc\r\ndef\rghi\njkl\r") == "abc\nghi\njkl"
+// ProcessCRLF("abc\r\ndef\rghi\rjkl\rmn") == "abc\nmnl"
 func ProcessCRLF(str string) string {
 	str = strings.ReplaceAll(str, "\r\n", "\n")
 
-	// process \r by erasing everything preceding it in the line
 	if strings.Contains(str, "\r") {
 		lines := strings.Split(str, "\n")
-		for idx := range lines {
-			for reCarriageReturn.MatchString(lines[idx]) {
-				lines[idx] = reCarriageReturn.ReplaceAllString(lines[idx], "")
+		for lineIdx, line := range lines {
+			if strings.Contains(line, "\r") {
+				lineRunes, newLineRunes := []rune(line), make([]rune, 0)
+				for idx, realIdx := 0, 0; idx < len(lineRunes); idx++ {
+					if lineRunes[idx] == '\r' {
+						realIdx = 0
+						continue
+					}
+
+					if realIdx < len(newLineRunes) {
+						newLineRunes[realIdx] = lineRunes[idx]
+					} else {
+						newLineRunes = append(newLineRunes, lineRunes[idx])
+					}
+					realIdx++
+				}
+				lines[lineIdx] = string(newLineRunes)
 			}
 		}
 		str = strings.Join(lines, "\n")

text/string_test.go

@@ -140,20 +140,23 @@ func ExampleProcessCRLF() {
 	fmt.Printf("%#v\n", ProcessCRLF("abc\r\ndef\rghi"))
 	fmt.Printf("%#v\n", ProcessCRLF("abc\r\ndef\rghi\njkl"))
 	fmt.Printf("%#v\n", ProcessCRLF("abc\r\ndef\rghi\njkl\r"))
+	fmt.Printf("%#v\n", ProcessCRLF("abc\r\ndef\rghi\rjkl\rmn"))
 
 	// Output: "abc"
 	// "abc\ndef"
 	// "abc\nghi"
 	// "abc\nghi\njkl"
-	// "abc\nghi\n"
+	// "abc\nghi\njkl"
+	// "abc\nmnl"
 }
 
 func TestProcessCRLF(t *testing.T) {
 	assert.Equal(t, "abc", ProcessCRLF("abc"))
 	assert.Equal(t, "abc\ndef", ProcessCRLF("abc\r\ndef"))
 	assert.Equal(t, "abc\nghi", ProcessCRLF("abc\r\ndef\rghi"))
 	assert.Equal(t, "abc\nghi\njkl", ProcessCRLF("abc\r\ndef\rghi\njkl"))
-	assert.Equal(t, "abc\nghi\n", ProcessCRLF("abc\r\ndef\rghi\njkl\r"))
+	assert.Equal(t, "abc\nghi\njkl", ProcessCRLF("abc\r\ndef\rghi\njkl\r"))
+	assert.Equal(t, "abc\nmnl", ProcessCRLF("abc\r\ndef\rghi\rjkl\rmn"))
 }
 
 func ExampleRepeatAndTrim() {