Support colon delimiter in ANSI escape sequences

# Both should work
    printf "\e[38;5;208mOption 1\e[m\nOption 2" | fzf --ansi
    printf "\e[38:5:208mOption 1\e[m\nOption 2" | fzf --ansi

This change makes ANSI parsing slightly slower.

    cpu: Intel(R) Core(TM) i7-8850H CPU @ 2.60GHz

    Before:
      BenchmarkNextAnsiEscapeSequence-12            992.22 MB/s
      BenchmarkExtractColor-12                      174.35 MB/s

    After:
      BenchmarkNextAnsiEscapeSequence-12            925.05 MB/s
      BenchmarkExtractColor-12                      163.33 MB/s

Fix #2913

CHANGELOG.md

@@ -1,6 +1,14 @@
 CHANGELOG
 =========
 
+0.32.2
+------
+- ANSI color sequences with colon delimiters are now supported.
+  ```sh
+  printf "\e[38;5;208mOption 1\e[m\nOption 2" | fzf --ansi
+  printf "\e[38:5:208mOption 1\e[m\nOption 2" | fzf --ansi
+  ```
+
 0.32.1
 ------
 - Fixed incorrect ordering of `--tiebreak=chunk`

src/ansi.go

@@ -85,7 +85,7 @@ func isPrint(c uint8) bool {
 }
 
 func matchOperatingSystemCommand(s string) int {
-	// `\x1b][0-9];[[:print:]]+(?:\x1b\\\\|\x07)`
+	// `\x1b][0-9][;:][[:print:]]+(?:\x1b\\\\|\x07)`
 	//                        ^ match starting here
 	//
 	i := 5 // prefix matched in nextAnsiEscapeSequence()
@@ -103,11 +103,11 @@ func matchOperatingSystemCommand(s string) int {
 }
 
 func matchControlSequence(s string) int {
-	// `\x1b[\\[()][0-9;?]*[a-zA-Z@]`
-	//                    ^ match starting here
+	// `\x1b[\\[()][0-9;:?]*[a-zA-Z@]`
+	//                     ^ match starting here
 	//
 	i := 2 // prefix matched in nextAnsiEscapeSequence()
-	for ; i < len(s) && (isNumeric(s[i]) || s[i] == ';' || s[i] == '?'); i++ {
+	for ; i < len(s) && (isNumeric(s[i]) || s[i] == ';' || s[i] == ':' || s[i] == '?'); i++ {
 	}
 	if i < len(s) {
 		c := s[i]
@@ -125,7 +125,7 @@ func isCtrlSeqStart(c uint8) bool {
 // nextAnsiEscapeSequence returns the ANSI escape sequence and is equivalent to
 // calling FindStringIndex() on the below regex (which was originally used):
 //
-// "(?:\x1b[\\[()][0-9;?]*[a-zA-Z@]|\x1b][0-9];[[:print:]]+(?:\x1b\\\\|\x07)|\x1b.|[\x0e\x0f]|.\x08)"
+// "(?:\x1b[\\[()][0-9;:?]*[a-zA-Z@]|\x1b][0-9][;:][[:print:]]+(?:\x1b\\\\|\x07)|\x1b.|[\x0e\x0f]|.\x08)"
 func nextAnsiEscapeSequence(s string) (int, int) {
 	// fast check for ANSI escape sequences
 	i := 0
@@ -153,16 +153,16 @@ Loop:
 				return i - n, i + 1
 			}
 		case '\x1b':
-			// match: `\x1b[\\[()][0-9;?]*[a-zA-Z@]`
+			// match: `\x1b[\\[()][0-9;:?]*[a-zA-Z@]`
 			if i+2 < len(s) && isCtrlSeqStart(s[i+1]) {
 				if j := matchControlSequence(s[i:]); j != -1 {
 					return i, i + j
 				}
 			}
 
-			// match: `\x1b][0-9];[[:print:]]+(?:\x1b\\\\|\x07)`
+			// match: `\x1b][0-9][;:][[:print:]]+(?:\x1b\\\\|\x07)`
 			if i+5 < len(s) && s[i+1] == ']' && isNumeric(s[i+2]) &&
-				s[i+3] == ';' && isPrint(s[i+4]) {
+				(s[i+3] == ';' || s[i+3] == ':') && isPrint(s[i+4]) {
 
 				if j := matchOperatingSystemCommand(s[i:]); j != -1 {
 					return i, i + j
@@ -279,9 +279,20 @@ func extractColor(str string, state *ansiState, proc func(string, *ansiState) bo
 	return trimmed, nil, state
 }
 
-func parseAnsiCode(s string) (int, string) {
+func parseAnsiCode(s string, delimiter byte) (int, byte, string) {
 	var remaining string
-	if i := strings.IndexByte(s, ';'); i >= 0 {
+	i := -1
+	if delimiter == 0 {
+		// Faster than strings.IndexAny(";:")
+		i = strings.IndexByte(s, ';')
+		if i < 0 {
+			i = strings.IndexByte(s, ':')
+		}
+	} else {
+		i = strings.IndexByte(s, delimiter)
+	}
+	if i >= 0 {
+		delimiter = s[i]
 		remaining = s[i+1:]
 		s = s[:i]
 	}
@@ -293,14 +304,14 @@ func parseAnsiCode(s string) (int, string) {
 		for _, ch := range []byte(s) {
 			ch -= '0'
 			if ch > 9 {
-				return -1, remaining
+				return -1, delimiter, remaining
 			}
 			code = code*10 + int(ch)
 		}
-		return code, remaining
+		return code, delimiter, remaining
 	}
 
-	return -1, remaining
+	return -1, delimiter, remaining
 }
 
 func interpretCode(ansiCode string, prevState *ansiState) ansiState {
@@ -328,9 +339,10 @@ func interpretCode(ansiCode string, prevState *ansiState) ansiState {
 	state256 := 0
 	ptr := &state.fg
 
+	var delimiter byte = 0
 	for len(ansiCode) != 0 {
 		var num int
-		if num, ansiCode = parseAnsiCode(ansiCode); num != -1 {
+		if num, delimiter, ansiCode = parseAnsiCode(ansiCode, delimiter); num != -1 {
 			switch state256 {
 			case 0:
 				switch num {

src/ansi_test.go

@@ -358,6 +358,7 @@ func TestAnsiCodeStringConversion(t *testing.T) {
 	assert("\x1b[31m", &ansiState{fg: 4, bg: 4, lbg: -1}, "\x1b[31;44m")
 	assert("\x1b[1;2;31m", &ansiState{fg: 2, bg: -1, attr: tui.Reverse, lbg: -1}, "\x1b[1;2;7;31;49m")
 	assert("\x1b[38;5;100;48;5;200m", nil, "\x1b[38;5;100;48;5;200m")
+	assert("\x1b[38:5:100:48:5:200m", nil, "\x1b[38;5;100;48;5;200m")
 	assert("\x1b[48;5;100;38;5;200m", nil, "\x1b[38;5;200;48;5;100m")
 	assert("\x1b[48;5;100;38;2;10;20;30;1m", nil, "\x1b[1;38;2;10;20;30;48;5;100m")
 	assert("\x1b[48;5;100;38;2;10;20;30;7m",
@@ -377,7 +378,7 @@ func TestParseAnsiCode(t *testing.T) {
 		{"-2", "", -1},
 	}
 	for _, x := range tests {
-		n, s := parseAnsiCode(x.In)
+		n, _, s := parseAnsiCode(x.In, 0)
 		if n != x.N || s != x.Exp {
 			t.Fatalf("%q: got: (%d %q) want: (%d %q)", x.In, n, s, x.N, x.Exp)
 		}
@@ -385,9 +386,9 @@ func TestParseAnsiCode(t *testing.T) {
 }
 
 // kernel/bpf/preload/iterators/README
-const ansiBenchmarkString = "\x1b[38;5;81m\x1b[01;31m\x1b[Kkernel/\x1b[0m\x1b[38;5;81mbpf/" +
-	"\x1b[0m\x1b[38;5;81mpreload/\x1b[0m\x1b[38;5;81miterators/" +
-	"\x1b[0m\x1b[38;5;149mMakefile\x1b[m\x1b[K\x1b[0m"
+const ansiBenchmarkString = "\x1b[38;5;81m\x1b[01;31m\x1b[Kkernel/\x1b[0m\x1b[38:5:81mbpf/" +
+	"\x1b[0m\x1b[38:5:81mpreload/\x1b[0m\x1b[38;5;81miterators/" +
+	"\x1b[0m\x1b[38:5:149mMakefile\x1b[m\x1b[K\x1b[0m"
 
 func BenchmarkNextAnsiEscapeSequence(b *testing.B) {
 	b.SetBytes(int64(len(ansiBenchmarkString)))