Files
cclip/vendor/github.com/charmbracelet/x/input/parse.go
PhatPhuckDave 3c5e991ec5 Add vendor
Specifically because I want to modify a dependency
2024-08-26 01:01:04 +02:00

837 lines
20 KiB
Go

package input
import (
"encoding/base64"
"strings"
"unicode/utf8"
"github.com/charmbracelet/x/ansi"
"github.com/charmbracelet/x/ansi/parser"
"github.com/erikgeiser/coninput"
)
// Flags to control the behavior of the parser.
const (
// When this flag is set, the driver will treat both Ctrl+Space and Ctrl+@
// as the same key sequence.
//
// Historically, the ANSI specs generate NUL (0x00) on both the Ctrl+Space
// and Ctrl+@ key sequences. This flag allows the driver to treat both as
// the same key sequence.
FlagCtrlAt = 1 << iota
// When this flag is set, the driver will treat the Tab key and Ctrl+I as
// the same key sequence.
//
// Historically, the ANSI specs generate HT (0x09) on both the Tab key and
// Ctrl+I. This flag allows the driver to treat both as the same key
// sequence.
FlagCtrlI
// When this flag is set, the driver will treat the Enter key and Ctrl+M as
// the same key sequence.
//
// Historically, the ANSI specs generate CR (0x0D) on both the Enter key
// and Ctrl+M. This flag allows the driver to treat both as the same key
FlagCtrlM
// When this flag is set, the driver will treat Escape and Ctrl+[ as
// the same key sequence.
//
// Historically, the ANSI specs generate ESC (0x1B) on both the Escape key
// and Ctrl+[. This flag allows the driver to treat both as the same key
// sequence.
FlagCtrlOpenBracket
// When this flag is set, the driver will send a BS (0x08 byte) character
// instead of a DEL (0x7F byte) character when the Backspace key is
// pressed.
//
// The VT100 terminal has both a Backspace and a Delete key. The VT220
// terminal dropped the Backspace key and replaced it with the Delete key.
// Both terminals send a DEL character when the Delete key is pressed.
// Modern terminals and PCs later readded the Delete key but used a
// different key sequence, and the Backspace key was standardized to send a
// DEL character.
FlagBackspace
// When this flag is set, the driver will recognize the Find key instead of
// treating it as a Home key.
//
// The Find key was part of the VT220 keyboard, and is no longer used in
// modern day PCs.
FlagFind
// When this flag is set, the driver will recognize the Select key instead
// of treating it as a End key.
//
// The Symbol key was part of the VT220 keyboard, and is no longer used in
// modern day PCs.
FlagSelect
// When this flag is set, the driver will use Terminfo databases to
// overwrite the default key sequences.
FlagTerminfo
// When this flag is set, the driver will preserve function keys (F13-F63)
// as symbols.
//
// Since these keys are not part of today's standard 20th century keyboard,
// we treat them as F1-F12 modifier keys i.e. ctrl/shift/alt + Fn combos.
// Key definitions come from Terminfo, this flag is only useful when
// FlagTerminfo is not set.
FlagFKeys
)
var flags int
// SetFlags sets the flags for the parser.
// This will control the behavior of ParseSequence.
func SetFlags(f int) {
flags = f
}
// ParseSequence finds the first recognized event sequence and returns it along
// with its length.
//
// It will return zero and nil no sequence is recognized or when the buffer is
// empty. If a sequence is not supported, an UnknownEvent is returned.
func ParseSequence(buf []byte) (n int, e Event) {
if len(buf) == 0 {
return 0, nil
}
switch b := buf[0]; b {
case ansi.ESC:
if len(buf) == 1 {
// Escape key
return 1, KeyDownEvent{Sym: KeyEscape}
}
switch b := buf[1]; b {
case 'O': // Esc-prefixed SS3
return parseSs3(buf)
case 'P': // Esc-prefixed DCS
return parseDcs(buf)
case '[': // Esc-prefixed CSI
return parseCsi(buf)
case ']': // Esc-prefixed OSC
return parseOsc(buf)
case '_': // Esc-prefixed APC
return parseApc(buf)
default:
n, e := ParseSequence(buf[1:])
if k, ok := e.(KeyDownEvent); ok && !k.Mod.IsAlt() {
k.Mod |= Alt
return n + 1, k
}
// Not a key sequence, nor an alt modified key sequence. In that
// case, just report a single escape key.
return 1, KeyDownEvent{Sym: KeyEscape}
}
case ansi.SS3:
return parseSs3(buf)
case ansi.DCS:
return parseDcs(buf)
case ansi.CSI:
return parseCsi(buf)
case ansi.OSC:
return parseOsc(buf)
case ansi.APC:
return parseApc(buf)
default:
if b <= ansi.US || b == ansi.DEL || b == ansi.SP {
return 1, parseControl(b)
} else if b >= ansi.PAD && b <= ansi.APC {
// C1 control code
// UTF-8 never starts with a C1 control code
// Encode these as Ctrl+Alt+<code - 0x40>
return 1, KeyDownEvent{Rune: rune(b) - 0x40, Mod: Ctrl | Alt}
}
return parseUtf8(buf)
}
}
func parseCsi(b []byte) (int, Event) {
if len(b) == 2 && b[0] == ansi.ESC {
// short cut if this is an alt+[ key
return 2, KeyDownEvent{Rune: rune(b[1]), Mod: Alt}
}
var csi ansi.CsiSequence
var params [parser.MaxParamsSize]int
var paramsLen int
var i int
if b[i] == ansi.CSI || b[i] == ansi.ESC {
i++
}
if i < len(b) && b[i-1] == ansi.ESC && b[i] == '[' {
i++
}
// Initial CSI byte
if i < len(b) && b[i] >= '<' && b[i] <= '?' {
csi.Cmd |= int(b[i]) << parser.MarkerShift
}
// Scan parameter bytes in the range 0x30-0x3F
var j int
for j = 0; i < len(b) && paramsLen < len(params) && b[i] >= 0x30 && b[i] <= 0x3F; i, j = i+1, j+1 {
if b[i] >= '0' && b[i] <= '9' {
if params[paramsLen] == parser.MissingParam {
params[paramsLen] = 0
}
params[paramsLen] *= 10
params[paramsLen] += int(b[i]) - '0'
}
if b[i] == ':' {
params[paramsLen] |= parser.HasMoreFlag
}
if b[i] == ';' || b[i] == ':' {
paramsLen++
if paramsLen < len(params) {
// Don't overflow the params slice
params[paramsLen] = parser.MissingParam
}
}
}
if j > 0 && paramsLen < len(params) {
// has parameters
paramsLen++
}
// Scan intermediate bytes in the range 0x20-0x2F
var intermed byte
for ; i < len(b) && b[i] >= 0x20 && b[i] <= 0x2F; i++ {
intermed = b[i]
}
// Set the intermediate byte
csi.Cmd |= int(intermed) << parser.IntermedShift
// Scan final byte in the range 0x40-0x7E
if i >= len(b) || b[i] < 0x40 || b[i] > 0x7E {
// Special case for URxvt keys
// CSI <number> $ is an invalid sequence, but URxvt uses it for
// shift modified keys.
if b[i-1] == '$' {
n, ev := parseCsi(append(b[:i-1], '~'))
if k, ok := ev.(KeyDownEvent); ok {
k.Mod |= Shift
return n, k
}
}
return i, UnknownEvent(b[:i-1])
}
// Add the final byte
csi.Cmd |= int(b[i])
i++
csi.Params = params[:paramsLen]
marker, cmd := csi.Marker(), csi.Command()
switch marker {
case '?':
switch cmd {
case 'y':
switch intermed {
case '$':
// Report Mode (DECRPM)
if paramsLen != 2 {
return i, UnknownCsiEvent(b[:i])
}
return i, ReportModeEvent{Mode: csi.Param(0), Value: csi.Param(1)}
}
case 'c':
// Primary Device Attributes
return i, parsePrimaryDevAttrs(&csi)
case 'u':
// Kitty keyboard flags
if param := csi.Param(0); param != -1 {
return i, KittyKeyboardEvent(param)
}
case 'R':
// This report may return a third parameter representing the page
// number, but we don't really need it.
if paramsLen >= 2 {
return i, CursorPositionEvent{Row: csi.Param(0), Column: csi.Param(1)}
}
}
return i, UnknownCsiEvent(b[:i])
case '<':
switch cmd {
case 'm', 'M':
// Handle SGR mouse
if paramsLen != 3 {
return i, UnknownCsiEvent(b[:i])
}
return i, parseSGRMouseEvent(&csi)
default:
return i, UnknownCsiEvent(b[:i])
}
case '>':
switch cmd {
case 'm':
// XTerm modifyOtherKeys
if paramsLen != 2 || csi.Param(0) != 4 {
return i, UnknownCsiEvent(b[:i])
}
return i, ModifyOtherKeysEvent(csi.Param(1))
default:
return i, UnknownCsiEvent(b[:i])
}
case '=':
// We don't support any of these yet
return i, UnknownCsiEvent(b[:i])
}
switch cmd := csi.Command(); cmd {
case 'R':
// Cursor position report OR modified F3
if paramsLen == 0 {
return i, KeyDownEvent{Sym: KeyF3}
} else if paramsLen != 2 {
break
}
// XXX: We cannot differentiate between cursor position report and
// CSI 1 ; <mod> R (which is modified F3) when the cursor is at the
// row 1. In this case, we report a modified F3 event since it's more
// likely to be the case than the cursor being at the first row.
//
// For a non ambiguous cursor position report, use
// [ansi.RequestExtendedCursorPosition] (DECXCPR) instead.
if csi.Param(0) != 1 {
return i, CursorPositionEvent{Row: csi.Param(0), Column: csi.Param(1)}
}
fallthrough
case 'a', 'b', 'c', 'd', 'A', 'B', 'C', 'D', 'E', 'F', 'H', 'P', 'Q', 'S', 'Z':
var k KeyDownEvent
switch cmd {
case 'a', 'b', 'c', 'd':
k = KeyDownEvent{Sym: KeyUp + KeySym(cmd-'a'), Mod: Shift}
case 'A', 'B', 'C', 'D':
k = KeyDownEvent{Sym: KeyUp + KeySym(cmd-'A')}
case 'E':
k = KeyDownEvent{Sym: KeyBegin}
case 'F':
k = KeyDownEvent{Sym: KeyEnd}
case 'H':
k = KeyDownEvent{Sym: KeyHome}
case 'P', 'Q', 'R', 'S':
k = KeyDownEvent{Sym: KeyF1 + KeySym(cmd-'P')}
case 'Z':
k = KeyDownEvent{Sym: KeyTab, Mod: Shift}
}
if paramsLen > 1 && csi.Param(0) == 1 {
// CSI 1 ; <modifiers> A
if paramsLen > 1 {
k.Mod |= KeyMod(csi.Param(1) - 1)
}
}
return i, k
case 'M':
// Handle X10 mouse
if i+3 > len(b) {
return i, UnknownCsiEvent(b[:i])
}
return i + 3, parseX10MouseEvent(append(b[:i], b[i:i+3]...))
case 'y':
// Report Mode (DECRPM)
if paramsLen != 2 {
return i, UnknownCsiEvent(b[:i])
}
return i, ReportModeEvent{Mode: csi.Param(0), Value: csi.Param(1)}
case 'u':
// Kitty keyboard protocol & CSI u (fixterms)
if paramsLen == 0 {
return i, UnknownCsiEvent(b[:i])
}
return i, parseKittyKeyboard(&csi)
case '_':
// Win32 Input Mode
if paramsLen != 6 {
return i, UnknownCsiEvent(b[:i])
}
rc := uint16(csi.Param(5))
if rc == 0 {
rc = 1
}
event := parseWin32InputKeyEvent(
coninput.VirtualKeyCode(csi.Param(0)), // Vk wVirtualKeyCode
coninput.VirtualKeyCode(csi.Param(1)), // Sc wVirtualScanCode
rune(csi.Param(2)), // Uc UnicodeChar
csi.Param(3) == 1, // Kd bKeyDown
coninput.ControlKeyState(csi.Param(4)), // Cs dwControlKeyState
rc, // Rc wRepeatCount
)
if event == nil {
return i, UnknownCsiEvent(b[:])
}
return i, event
case '@', '^', '~':
if paramsLen == 0 {
return i, UnknownCsiEvent(b[:i])
}
param := csi.Param(0)
switch cmd {
case '~':
switch param {
case 27:
// XTerm modifyOtherKeys 2
if paramsLen != 3 {
return i, UnknownCsiEvent(b[:i])
}
return i, parseXTermModifyOtherKeys(&csi)
case 200:
// bracketed-paste start
return i, PasteStartEvent{}
case 201:
// bracketed-paste end
return i, PasteEndEvent{}
}
}
switch param {
case 1, 2, 3, 4, 5, 6, 7, 8:
fallthrough
case 11, 12, 13, 14, 15:
fallthrough
case 17, 18, 19, 20, 21, 23, 24, 25, 26:
fallthrough
case 28, 29, 31, 32, 33, 34:
var k KeyDownEvent
switch param {
case 1:
if flags&FlagFind != 0 {
k = KeyDownEvent{Sym: KeyFind}
} else {
k = KeyDownEvent{Sym: KeyHome}
}
case 2:
k = KeyDownEvent{Sym: KeyInsert}
case 3:
k = KeyDownEvent{Sym: KeyDelete}
case 4:
if flags&FlagSelect != 0 {
k = KeyDownEvent{Sym: KeySelect}
} else {
k = KeyDownEvent{Sym: KeyEnd}
}
case 5:
k = KeyDownEvent{Sym: KeyPgUp}
case 6:
k = KeyDownEvent{Sym: KeyPgDown}
case 7:
k = KeyDownEvent{Sym: KeyHome}
case 8:
k = KeyDownEvent{Sym: KeyEnd}
case 11, 12, 13, 14, 15:
k = KeyDownEvent{Sym: KeyF1 + KeySym(param-11)}
case 17, 18, 19, 20, 21:
k = KeyDownEvent{Sym: KeyF6 + KeySym(param-17)}
case 23, 24, 25, 26:
k = KeyDownEvent{Sym: KeyF11 + KeySym(param-23)}
case 28, 29:
k = KeyDownEvent{Sym: KeyF15 + KeySym(param-28)}
case 31, 32, 33, 34:
k = KeyDownEvent{Sym: KeyF17 + KeySym(param-31)}
}
// modifiers
if paramsLen > 1 {
k.Mod |= KeyMod(csi.Param(1) - 1)
}
// Handle URxvt weird keys
switch cmd {
case '^':
k.Mod |= Ctrl
case '@':
k.Mod |= Ctrl | Shift
}
return i, k
}
}
return i, UnknownCsiEvent(b[:i])
}
// parseSs3 parses a SS3 sequence.
// See https://vt100.net/docs/vt220-rm/chapter4.html#S4.4.4.2
func parseSs3(b []byte) (int, Event) {
if len(b) == 2 && b[0] == ansi.ESC {
// short cut if this is an alt+O key
return 2, KeyDownEvent{Rune: rune(b[1]), Mod: Alt}
}
var i int
if b[i] == ansi.SS3 || b[i] == ansi.ESC {
i++
}
if i < len(b) && b[i-1] == ansi.ESC && b[i] == 'O' {
i++
}
// Scan numbers from 0-9
var mod int
for ; i < len(b) && b[i] >= '0' && b[i] <= '9'; i++ {
mod *= 10
mod += int(b[i]) - '0'
}
// Scan a GL character
// A GL character is a single byte in the range 0x21-0x7E
// See https://vt100.net/docs/vt220-rm/chapter2.html#S2.3.2
if i >= len(b) || b[i] < 0x21 || b[i] > 0x7E {
return i, UnknownEvent(b[:i])
}
// GL character(s)
gl := b[i]
i++
var k KeyDownEvent
switch gl {
case 'a', 'b', 'c', 'd':
k = KeyDownEvent{Sym: KeyUp + KeySym(gl-'a'), Mod: Ctrl}
case 'A', 'B', 'C', 'D':
k = KeyDownEvent{Sym: KeyUp + KeySym(gl-'A')}
case 'E':
k = KeyDownEvent{Sym: KeyBegin}
case 'F':
k = KeyDownEvent{Sym: KeyEnd}
case 'H':
k = KeyDownEvent{Sym: KeyHome}
case 'P', 'Q', 'R', 'S':
k = KeyDownEvent{Sym: KeyF1 + KeySym(gl-'P')}
case 'M':
k = KeyDownEvent{Sym: KeyKpEnter}
case 'X':
k = KeyDownEvent{Sym: KeyKpEqual}
case 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y':
k = KeyDownEvent{Sym: KeyKpMultiply + KeySym(gl-'j')}
default:
return i, UnknownSs3Event(b[:i])
}
// Handle weird SS3 <modifier> Func
if mod > 0 {
k.Mod |= KeyMod(mod - 1)
}
return i, k
}
func parseOsc(b []byte) (int, Event) {
if len(b) == 2 && b[0] == ansi.ESC {
// short cut if this is an alt+] key
return 2, KeyDownEvent{Rune: rune(b[1]), Mod: Alt}
}
var i int
if b[i] == ansi.OSC || b[i] == ansi.ESC {
i++
}
if i < len(b) && b[i-1] == ansi.ESC && b[i] == ']' {
i++
}
// Parse OSC command
// An OSC sequence is terminated by a BEL, ESC, or ST character
var start, end int
cmd := -1
for ; i < len(b) && b[i] >= '0' && b[i] <= '9'; i++ {
if cmd == -1 {
cmd = 0
} else {
cmd *= 10
}
cmd += int(b[i]) - '0'
}
if i < len(b) && b[i] == ';' {
// mark the start of the sequence data
i++
start = i
}
for ; i < len(b); i++ {
// advance to the end of the sequence
if b[i] == ansi.BEL || b[i] == ansi.ESC || b[i] == ansi.ST {
break
}
}
if i >= len(b) {
return i, UnknownEvent(b[:i])
}
end = i // end of the sequence data
i++
// Check 7-bit ST (string terminator) character
if i < len(b) && b[i-1] == ansi.ESC && b[i] == '\\' {
i++
}
if end <= start {
return i, UnknownOscEvent(b[:i])
}
data := string(b[start:end])
switch cmd {
case 10:
return i, ForegroundColorEvent{xParseColor(data)}
case 11:
return i, BackgroundColorEvent{xParseColor(data)}
case 12:
return i, CursorColorEvent{xParseColor(data)}
case 52:
parts := strings.Split(data, ";")
if len(parts) == 0 {
return i, ClipboardEvent("")
}
b64 := parts[len(parts)-1]
bts, err := base64.StdEncoding.DecodeString(b64)
if err != nil {
return i, ClipboardEvent("")
}
return i, ClipboardEvent(bts)
default:
return i, UnknownOscEvent(b[:i])
}
}
// parseStTerminated parses a control sequence that gets terminated by a ST character.
func parseStTerminated(intro8, intro7 byte) func([]byte) (int, Event) {
return func(b []byte) (int, Event) {
var i int
if b[i] == intro8 || b[i] == ansi.ESC {
i++
}
if i < len(b) && b[i-1] == ansi.ESC && b[i] == intro7 {
i++
}
// Scan control sequence
// Most common control sequence is terminated by a ST character
// ST is a 7-bit string terminator character is (ESC \)
// nolint: revive
for ; i < len(b) && b[i] != ansi.ST && b[i] != ansi.ESC; i++ {
}
if i >= len(b) {
switch intro8 {
case ansi.DCS:
return i, UnknownDcsEvent(b[:i])
case ansi.APC:
return i, UnknownApcEvent(b[:i])
default:
return i, UnknownEvent(b[:i])
}
}
i++
// Check 7-bit ST (string terminator) character
if i < len(b) && b[i-1] == ansi.ESC && b[i] == '\\' {
i++
}
switch intro8 {
case ansi.DCS:
return i, UnknownDcsEvent(b[:i])
case ansi.APC:
return i, UnknownApcEvent(b[:i])
default:
return i, UnknownEvent(b[:i])
}
}
}
func parseDcs(b []byte) (int, Event) {
if len(b) == 2 && b[0] == ansi.ESC {
// short cut if this is an alt+P key
return 2, KeyDownEvent{Rune: rune(b[1]), Mod: Alt}
}
var params [16]int
var paramsLen int
var dcs ansi.DcsSequence
// DCS sequences are introduced by DCS (0x90) or ESC P (0x1b 0x50)
var i int
if b[i] == ansi.DCS || b[i] == ansi.ESC {
i++
}
if i < len(b) && b[i-1] == ansi.ESC && b[i] == 'P' {
i++
}
// initial DCS byte
if i < len(b) && b[i] >= '<' && b[i] <= '?' {
dcs.Cmd |= int(b[i]) << parser.MarkerShift
}
// Scan parameter bytes in the range 0x30-0x3F
var j int
for j = 0; i < len(b) && paramsLen < len(params) && b[i] >= 0x30 && b[i] <= 0x3F; i, j = i+1, j+1 {
if b[i] >= '0' && b[i] <= '9' {
if params[paramsLen] == parser.MissingParam {
params[paramsLen] = 0
}
params[paramsLen] *= 10
params[paramsLen] += int(b[i]) - '0'
}
if b[i] == ':' {
params[paramsLen] |= parser.HasMoreFlag
}
if b[i] == ';' || b[i] == ':' {
paramsLen++
if paramsLen < len(params) {
// Don't overflow the params slice
params[paramsLen] = parser.MissingParam
}
}
}
if j > 0 && paramsLen < len(params) {
// has parameters
paramsLen++
}
// Scan intermediate bytes in the range 0x20-0x2F
var intermed byte
for j := 0; i < len(b) && b[i] >= 0x20 && b[i] <= 0x2F; i, j = i+1, j+1 {
intermed = b[i]
}
// set intermediate byte
dcs.Cmd |= int(intermed) << parser.IntermedShift
// Scan final byte in the range 0x40-0x7E
if i >= len(b) || b[i] < 0x40 || b[i] > 0x7E {
return i, UnknownEvent(b[:i])
}
// Add the final byte
dcs.Cmd |= int(b[i])
i++
start := i // start of the sequence data
for ; i < len(b); i++ {
if b[i] == ansi.ST || b[i] == ansi.ESC {
break
}
}
if i >= len(b) {
return i, UnknownEvent(b[:i])
}
end := i // end of the sequence data
i++
// Check 7-bit ST (string terminator) character
if i < len(b) && b[i-1] == ansi.ESC && b[i] == '\\' {
i++
}
dcs.Params = params[:paramsLen]
switch cmd := dcs.Command(); cmd {
case 'r':
switch dcs.Intermediate() {
case '+':
// XTGETTCAP responses
switch param := dcs.Param(0); param {
case 0, 1:
tc := parseTermcap(b[start:end])
// XXX: some terminals like KiTTY report invalid responses with
// their queries i.e. sending a query for "Tc" using "\x1bP+q5463\x1b\\"
// returns "\x1bP0+r5463\x1b\\".
// The specs says that invalid responses should be in the form of
// DCS 0 + r ST "\x1bP0+r\x1b\\"
//
// See: https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Operating-System-Commands
tc.IsValid = param == 1
return i, tc
}
}
}
return i, UnknownDcsEvent(b[:i])
}
func parseApc(b []byte) (int, Event) {
if len(b) == 2 && b[0] == ansi.ESC {
// short cut if this is an alt+_ key
return 2, KeyDownEvent{Rune: rune(b[1]), Mod: Alt}
}
// APC sequences are introduced by APC (0x9f) or ESC _ (0x1b 0x5f)
return parseStTerminated(ansi.APC, '_')(b)
}
func parseUtf8(b []byte) (int, Event) {
r, rw := utf8.DecodeRune(b)
if r <= ansi.US || r == ansi.DEL || r == ansi.SP {
// Control codes get handled by parseControl
return 1, parseControl(byte(r))
} else if r == utf8.RuneError {
return 1, UnknownEvent(b[0])
}
return rw, KeyDownEvent{Rune: r}
}
func parseControl(b byte) Event {
switch b {
case ansi.NUL:
if flags&FlagCtrlAt != 0 {
return KeyDownEvent{Rune: '@', Mod: Ctrl}
}
return KeyDownEvent{Rune: ' ', Sym: KeySpace, Mod: Ctrl}
case ansi.BS:
return KeyDownEvent{Rune: 'h', Mod: Ctrl}
case ansi.HT:
if flags&FlagCtrlI != 0 {
return KeyDownEvent{Rune: 'i', Mod: Ctrl}
}
return KeyDownEvent{Sym: KeyTab}
case ansi.CR:
if flags&FlagCtrlM != 0 {
return KeyDownEvent{Rune: 'm', Mod: Ctrl}
}
return KeyDownEvent{Sym: KeyEnter}
case ansi.ESC:
if flags&FlagCtrlOpenBracket != 0 {
return KeyDownEvent{Rune: '[', Mod: Ctrl}
}
return KeyDownEvent{Sym: KeyEscape}
case ansi.DEL:
if flags&FlagBackspace != 0 {
return KeyDownEvent{Sym: KeyDelete}
}
return KeyDownEvent{Sym: KeyBackspace}
case ansi.SP:
return KeyDownEvent{Sym: KeySpace, Rune: ' '}
default:
if b >= ansi.SOH && b <= ansi.SUB {
// Use lower case letters for control codes
return KeyDownEvent{Rune: rune(b + 0x60), Mod: Ctrl}
} else if b >= ansi.FS && b <= ansi.US {
return KeyDownEvent{Rune: rune(b + 0x40), Mod: Ctrl}
}
return UnknownEvent(b)
}
}