COOKED_READ_DATA, aka conhost's readline implementation

Test instructions

All of the following ✅ marks must be fulfilled during manual testing:

• ASCII input
• Chinese input (中文維基百科) ✅
• Surrogate pair input (🙂) ✅
• In cmd.exe
  • Create 2 file: "a😊b.txt" and "a😟b.txt"
  • Press tab: Autocomplete to "a😊b.txt" ✅
  • Navigate the cursor right past the "a"
  • Press tab twice: Autocomplete to "a😟b.txt" ✅
• Execute printf(" "); gets(buffer); in C (or equivalent)
  • Press Tab, A, Ctrl+V, Tab, A ✅
  • The prompt is " A^V A" ✅
  • Cursor navigation works ✅
  • Backspacing/Deleting random parts of it works ✅
  • It never deletes the initial 4 spaces ✅
• Backspace deletes preceding glyphs ✅
• Ctrl+Backspace deletes preceding words ✅
• Escape clears input ✅
• Home navigates to start ✅
• Ctrl+Home deletes text between cursor and start ✅
• End navigates to end ✅
• Ctrl+End deletes text between cursor and end ✅
• Left navigates over previous code points ✅
• Ctrl+Left navigates to previous word-starts ✅
• Right and F1 navigate over next code points ✅
  • Pressing right at the end of input copies characters from the previous command ✅
• Ctrl+Right navigates to next word-ends ✅
• Insert toggles overwrite mode ✅
• Delete deletes next code point ✅
• Up and F5 cycle through history ✅
  • Doesn't crash with no history ✅
  • Stops at first entry ✅
• Down cycles through history ✅
  • Doesn't crash with no history ✅
  • Stops at last entry ✅
• PageUp retrieves the oldest command ✅
• PageDown retrieves the newest command ✅
• F2 starts "copy to char" prompt ✅
  • Escape dismisses prompt ✅
  • Typing a character copies text from the previous command up until that character into the current buffer (acts identical to F3, but with automatic character search) ✅
• F3 copies the previous command into the current buffer, starting at the current cursor position, for as many characters as possible ✅
  • Doesn't erase trailing text if the current buffer is longer than the previous command ✅
  • Puts the cursor at the end of the copied text ✅
• F4 starts "copy from char" prompt ✅
  • Escape dismisses prompt ✅
  • Erases text between the current cursor position and the first instance of a given char (but not including it) ✅
• F6 inserts Ctrl+Z ✅
• F7 without modifiers starts "command list" prompt ✅
  • Escape dismisses prompt ✅
  • Entries wider than the window width are truncated ✅
  • Height expands up to 20 rows with longer histories ✅
  • F9 starts "command number" prompt ✅
  • Left/Right replace the buffer with the given command ✅
    • And put cursor at the end of the buffer ✅
  • Up/Down navigate selection through history ✅
    • Stops at start/end with <10 entries ✅
    • Stops at start/end with >20 entries ✅
    • Scrolls through the entries if there are too many ✅
  • Shift+Up/Down moves history items around ✅
  • Home navigates to first entry ✅
  • End navigates to last entry ✅
  • PageUp navigates by $height items at a time or to first ✅
  • PageDown navigates by $height items at a time or to last ✅
• Alt+F7 clears command history ✅
• F8 cycles through commands that start with the same text as the current buffer up until the current cursor position ✅
  • Doesn't crash with no history ✅
• F9 starts "command number" prompt ✅
  • Escape dismisses prompt ✅
  • Ignores non-ASCII-decimal characters ✅
  • Allows entering between 1 and 5 digits ✅
  • Pressing Enter fetches the given command from the history ✅
• Alt+F10 clears doskey aliases ✅
• In cmd.exe, with an empty prompt in an empty directory: Pressing tab produces an audible bing and prints no text ✅
• When Narrator is enabled, in cmd.exe:
  • Typing individual characters announces only exactly each character that is being typed ✅
  • Backspacing at the end of a prompt announces only exactly each deleted character ✅