Module: TUITD::ANSIParser

Defined in:
lib/tui_td/ansi_parser.rb

Overview

Parses raw terminal output (ANSI escape sequences + text) into a structured state representation.

Handles:

  • SGR (Select Graphic Rendition) — colors, bold, italic, underline

  • Cursor movement (CUU, CUD, CUF, CUB, CUP)

  • Erase (ED, EL)

  • Line feed, carriage return, backspace, tab

Output: [[{char, fg, bg, bold, italic, underline]], cursor: col, size: cols}

rubocop:disable Metrics/ModuleLength

Constant Summary collapse

SGR_COLORS = 
{
  0 => :reset,
  1 => :bold,
  3 => :italic,
  4 => :underline,
  5 => :blink,
  7 => :reverse,
  22 => :normal,
  23 => :no_italic,
  24 => :no_underline,
  30 => :black,
  31 => :red,
  32 => :green,
  33 => :yellow,
  34 => :blue,
  35 => :magenta,
  36 => :cyan,
  37 => :white,
  38 => :xterm_fg,  # 38;5;N or 38;2;R;G;B
  39 => :default_fg,
  40 => :bg_black,
  41 => :bg_red,
  42 => :bg_green,
  43 => :bg_yellow,
  44 => :bg_blue,
  45 => :bg_magenta,
  46 => :bg_cyan,
  47 => :bg_white,
  48 => :xterm_bg,  # 48;5;N or 48;2;R;G;B
  49 => :default_bg,
  90 => :bright_black,
  91 => :bright_red,
  92 => :bright_green,
  93 => :bright_yellow,
  94 => :bright_blue,
  95 => :bright_magenta,
  96 => :bright_cyan,
  97 => :bright_white,
  100 => :bg_bright_black,
  101 => :bg_bright_red,
  102 => :bg_bright_green,
  103 => :bg_bright_yellow,
  104 => :bg_bright_blue,
  105 => :bg_bright_magenta,
  106 => :bg_bright_cyan,
  107 => :bg_bright_white,
}.freeze
SGR_16_TO_NAME = 
{
  0 => "black",
  1 => "red",
  2 => "green",
  3 => "yellow",
  4 => "blue",
  5 => "magenta",
  6 => "cyan",
  7 => "white",
  8 => "bright_black",
  9 => "bright_red",
  10 => "bright_green",
  11 => "bright_yellow",
  12 => "bright_blue",
  13 => "bright_magenta",
  14 => "bright_cyan",
  15 => "bright_white",
}.freeze
DEC_MAP = 
{
  "`" => "◆",
  "a" => "▒",
  "b" => "\u2409",
  "c" => "\u240C",
  "d" => "\u240D",
  "e" => "\u240A",
  "f" => "°",
  "g" => "±",
  "h" => "\u2424",
  "i" => "\u240B",
  "j" => "┘",
  "k" => "┐",
  "l" => "┌",
  "m" => "└",
  "n" => "┼",
  "o" => "⎺",
  "p" => "⎻",
  "q" => "─",
  "r" => "⎼",
  "s" => "⎽",
  "t" => "├",
  "u" => "┤",
  "v" => "┴",
  "w" => "┬",
  "x" => "│",
  "y" => "≤",
  "z" => "≥",
  "{" => "π",
  "|" => "≠",
  "}" => "£",
  "~" => "·",
}.freeze

Class Method Summary collapse

Class Method Details

._apply_csi(seq, cursor, attrs, grid, rows, cols, saved_cursor, scroll_region) ⇒ Object

rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity, Metrics/ParameterLists



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# File 'lib/tui_td/ansi_parser.rb', line 410

def self._apply_csi(seq, cursor, attrs, grid, rows, cols, saved_cursor, scroll_region)
  # Strip leading escape char if present
  cleaned = seq.sub(/^\e/, "")
  match = cleaned.match(/^\[(\??)([\d;]*)( ?)([A-HJ-KP-SX@`fhlmnRrsuq])$/)
  return [false, nil, {}] unless match

  is_private = (match[1] == "?")
  params = match[2].split(";").map(&:to_i)
  space = match[3]
  command = match[4]

  new_saved = nil
  action = {}

  case command
  when "m"
    _apply_sgr(params, attrs)
  when "A" # CUU — Cursor Up
    n = params[0] || 1
    n = 1 if n.zero?
    cursor[:row] = [cursor[:row] - n, 0].max
  when "B" # CUD — Cursor Down
    n = params[0] || 1
    n = 1 if n.zero?
    cursor[:row] = [cursor[:row] + n, rows - 1].min
  when "C" # CUF — Cursor Forward
    n = params[0] || 1
    n = 1 if n.zero?
    cursor[:col] = [cursor[:col] + n, cols - 1].min
  when "D" # CUB — Cursor Back
    n = params[0] || 1
    n = 1 if n.zero?
    cursor[:col] = [cursor[:col] - n, 0].max
  when "H", "f" # CUP — Cursor Position
    r = (params[0] || 1) - 1
    c = (params[1] || 1) - 1
    cursor[:row] = r.clamp(0, rows - 1)
    cursor[:col] = c.clamp(0, cols - 1)
  when "J" # ED — Erase in Display
    case params[0]
    when nil, 0
      _erase_down(cursor, grid, rows, cols)
    when 1
      _erase_up(cursor, grid, cols)
    when 2, 3
      _erase_all(grid, rows, cols)
      cursor[:row] = 0
      cursor[:col] = 0
    end
  when "K" # EL — Erase in Line
    case params[0]
    when nil, 0
      _erase_line_right(cursor, grid, cols)
    when 1
      _erase_line_left(cursor, grid, cols)
    when 2
      _erase_line(cursor, grid, cols)
    end
  when "X" # Erase Characters
    n = params[0] || 1
    n.times do |i|
      next unless cursor[:row] < rows && cursor[:col] + i < cols

      grid[cursor[:row]][cursor[:col] + i][:char] = " "
    end
  when "s" # DECSC — Save Cursor (CSI variant)
    new_saved = { row: cursor[:row], col: cursor[:col] }
  when "u" # DECRC — Restore Cursor (CSI variant)
    if saved_cursor
      cursor[:row] = saved_cursor[:row]
      cursor[:col] = saved_cursor[:col]
    end
  when "r" # DECSTBM — Set Scroll Region
    top = (params[0] || 1) - 1
    bottom = (params[1] || rows) - 1
    top = top.clamp(0, rows - 1)
    bottom = bottom.clamp(0, rows - 1)
    if top < bottom
      scroll_region[:top] = top
      scroll_region[:bottom] = bottom
    else
      scroll_region[:top] = 0
      scroll_region[:bottom] = rows - 1
    end
    cursor[:row] = 0
    cursor[:col] = 0
  when "h"
    if is_private
      params.each do |p|
        case p
        when 47, 1047, 1049
          action[:alt_screen] = true
          action[:alt_screen_code] = p
        when 25
          action[:cursor_visible] = true
        when 1000
          action[:mouse_mode] = :normal
        when 1002
          action[:mouse_mode] = :drag
        when 1003
          action[:mouse_mode] = :all
        when 1006
          action[:mouse_format] = :sgr
        end
      end
    end
  when "l"
    if is_private
      params.each do |p|
        case p
        when 47, 1047, 1049
          action[:alt_screen] = false
          action[:alt_screen_code] = p
        when 25
          action[:cursor_visible] = false
        when 1000, 1002, 1003
          action[:mouse_mode] = :none
        when 1006
          action[:mouse_format] = :normal
        end
      end
    end
  when "q"
    if space == " "
      style_val = params[0] || 0
      action[:cursor_style] = style_val
    end
  when "n" # DSR — Device Status Report request
    return [params[0] == 6, nil, {}]
  when "R" # DSR response (from terminal side) or CPR — ignore
    nil
  end

  [false, new_saved, action]
end

._apply_sgr(params, attrs) ⇒ Object

rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity



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# File 'lib/tui_td/ansi_parser.rb', line 548

def self._apply_sgr(params, attrs)
  if params.empty? || params == [0]
    return attrs.merge!(fg: "default", bg: "default", bold: false, italic: false, underline: false,
                        blink: false,)
  end

  i = 0
  while i < params.length
    p = params[i]
    case p
    when 0
      attrs.merge!(fg: "default", bg: "default", bold: false, italic: false, underline: false, blink: false)
    when 1
      attrs[:bold] = true
    when 3
      attrs[:italic] = true
    when 4
      attrs[:underline] = true
    when 5, 6
      attrs[:blink] = true
    when 22
      attrs[:bold] = false
    when 23
      attrs[:italic] = false
    when 24
      attrs[:underline] = false
    when 25
      attrs[:blink] = false
    when 7, 27
      # Reverse — swap fg and bg
      attrs[:fg], attrs[:bg] = attrs[:bg], attrs[:fg]
    when 30..37
      attrs[:fg] = SGR_16_TO_NAME[p - 30] || "color#{p - 30}"
    when 38
      # Extended foreground
      if params[i + 1] == 5
        color = params[i + 2]
        attrs[:fg] = "color#{color}"
        i += 2
      elsif params[i + 1] == 2
        r = params[i + 2]
        g = params[i + 3]
        b = params[i + 4]
        attrs[:fg] = format("#%<r>02x%<g>02x%<b>02x", r: r, g: g, b: b)
        i += 4
      end
    when 39
      attrs[:fg] = "default"
    when 40..47
      attrs[:bg] = SGR_16_TO_NAME[p - 40] || "bg_color#{p - 40}"
    when 48
      # Extended background
      if params[i + 1] == 5
        color = params[i + 2]
        attrs[:bg] = "color#{color}"
        i += 2
      elsif params[i + 1] == 2
        r = params[i + 2]
        g = params[i + 3]
        b = params[i + 4]
        attrs[:bg] = format("#%<r>02x%<g>02x%<b>02x", r: r, g: g, b: b)
        i += 4
      end
    when 49
      attrs[:bg] = "default"
    when 90..97
      attrs[:fg] = "bright_#{SGR_16_TO_NAME[p - 90] || "color#{p - 90 + 8}"}"
    when 100..107
      attrs[:bg] = "bright_#{SGR_16_TO_NAME[p - 100] || "color#{p - 100 + 8}"}"
    end
    i += 1
  end
end

._color_code(name, prefix) ⇒ Object

rubocop:disable Metrics/CyclomaticComplexity



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# File 'lib/tui_td/ansi_parser.rb', line 673

def self._color_code(name, prefix)
  case name
  when "default" then nil
  when /^#([0-9a-fA-F]{6})$/
    r = ::Regexp.last_match(1)[0..1].to_i(16)
    g = ::Regexp.last_match(1)[2..3].to_i(16)
    b = ::Regexp.last_match(1)[4..5].to_i(16)
    "#{prefix};2;#{r};#{g};#{b}"
  when /^(bright_)?(.+)$/
    base_name = ::Regexp.last_match(2)
    index = SGR_16_TO_NAME.key(base_name)
    index += 8 if ::Regexp.last_match(1) && index && index < 8
    index ? "#{prefix};5;#{index}" : nil
  end
end

._erase_all(grid, rows, cols) ⇒ Object 



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# File 'lib/tui_td/ansi_parser.rb', line 649

def self._erase_all(grid, rows, cols)
  rows.times do |ri|
    cols.times { |ci| grid[ri][ci][:char] = " " }
  end
end

._erase_down(cursor, grid, rows, cols) ⇒ Object

rubocop:enable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity



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# File 'lib/tui_td/ansi_parser.rb', line 623

def self._erase_down(cursor, grid, rows, cols)
  r = cursor[:row]
  c = cursor[:col]

  # Erase from cursor to end of line
  (c...cols).each { |ci| grid[r][ci][:char] = " " if r < rows }

  # Erase remaining lines
  ((r + 1)...rows).each do |ri|
    cols.times { |ci| grid[ri][ci][:char] = " " }
  end
end

._erase_line(cursor, grid, cols) ⇒ Object 



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# File 'lib/tui_td/ansi_parser.rb', line 667

def self._erase_line(cursor, grid, cols)
  r = cursor[:row]
  cols.times { |ci| grid[r][ci][:char] = " " if r < grid.length }
end

._erase_line_left(cursor, grid, _cols) ⇒ Object 



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# File 'lib/tui_td/ansi_parser.rb', line 661

def self._erase_line_left(cursor, grid, _cols)
  r = cursor[:row]
  c = cursor[:col]
  (0..c).each { |ci| grid[r][ci][:char] = " " if r < grid.length }
end

._erase_line_right(cursor, grid, cols) ⇒ Object 



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# File 'lib/tui_td/ansi_parser.rb', line 655

def self._erase_line_right(cursor, grid, cols)
  r = cursor[:row]
  c = cursor[:col]
  (c...cols).each { |ci| grid[r][ci][:char] = " " if r < grid.length }
end

._erase_up(cursor, grid, cols) ⇒ Object 



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# File 'lib/tui_td/ansi_parser.rb', line 636

def self._erase_up(cursor, grid, cols)
  r = cursor[:row]
  c = cursor[:col]

  # Erase lines above cursor
  (0...r).each do |ri|
    cols.times { |ci| grid[ri][ci][:char] = " " }
  end

  # Erase from start of line to cursor
  (0..c).each { |ci| grid[r][ci][:char] = " " }
end

._utf8_char_at(str, i) ⇒ Object

Extract a single UTF-8 character at position i in a binary string. Returns [char_string, byte_length] or nil if the byte is not printable/valid. rubocop:disable Metrics/CyclomaticComplexity, Metrics/PerceivedComplexity, Naming/MethodParameterName



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# File 'lib/tui_td/ansi_parser.rb', line 697

def self._utf8_char_at(str, i)
  byte = str.getbyte(i)
  return nil unless byte

  if byte < 0x80
    # Single-byte ASCII
    return nil unless byte >= 0x20 # only printable, skip control chars

    return [byte.chr, 1]
  end

  # Multi-byte UTF-8
  len = if byte & 0xE0 == 0xC0
          2
        elsif byte & 0xF0 == 0xE0
          3
        elsif byte & 0xF8 == 0xF0
          4
        else
          return nil # continuation byte or invalid — let main loop advance
        end
  return nil if i + len > str.bytesize

  bytes = str.byteslice(i, len)
  char = bytes.dup.force_encoding("UTF-8")
  return nil unless char.valid_encoding?

  [char, len]
rescue StandardError
  nil
end

.build_frame(state) ⇒ Object

Rebuild ANSI output from a state hash (for rendering/screenshot) rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity



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# File 'lib/tui_td/ansi_parser.rb', line 335

def self.build_frame(state)
  rows = state.dig(:size, :rows) || state["size"]["rows"]
  state.dig(:size, :cols) || state["size"]["cols"]
  grid = state[:rows] || state["rows"]
  cursor = state[:cursor] || state["cursor"]
  mouse_mode = state[:mouse_mode] || state["mouse_mode"] || :none
  mouse_format = state[:mouse_format] || state["mouse_format"] || :normal

  out = +""
  out << "\e[0m"
  out << "\e[2J\e[H"

  grid.each_with_index do |row, ri|
    row.each_with_index do |cell, _ci|
      char = cell[:char] || cell["char"] || " "
      fg = cell[:fg] || cell["fg"] || "default"
      bg = cell[:bg] || cell["bg"] || "default"
      bold = cell[:bold] || cell["bold"] || false
      italic = cell[:italic] || cell["italic"] || false
      underline = cell[:underline] || cell["underline"] || false
      blink = cell[:blink] || cell["blink"] || false

      codes = []
      codes << "1" if bold
      codes << "3" if italic
      codes << "4" if underline
      codes << "5" if blink

      fg_code = _color_code(fg, "38")
      bg_code = _color_code(bg, "48")

      codes << fg_code if fg_code
      codes << bg_code if bg_code

      out << "\e[#{codes.join(";")}m" unless codes.empty?
      out << char
    end
    out << "\n" if ri < rows - 1
  end

  # Reconstruct cursor visibility
  cursor_vis = true
  cursor_vis = cursor[:visible] != false && cursor["visible"] != false if cursor.is_a?(Hash)
  out << (cursor_vis ? "\e[?25h" : "\e[?25l")

  # Reconstruct cursor style
  if cursor.is_a?(Hash)
    style = cursor[:style] || cursor["style"]
    out << "\e[#{style} q" if style
  end

  # Reconstruct mouse mode and format
  out << case mouse_mode
         when :normal
           "\e[?1000h"
         when :drag
           "\e[?1002h"
         when :all
           "\e[?1003h"
         else
           "\e[?1000l\e[?1002l\e[?1003l"
         end

  out << if mouse_format == :sgr
           "\e[?1006h"
         else
           "\e[?1006l"
         end

  out << "\e[0m"
  out
end

.default_cell ⇒ Object

rubocop:enable Metrics/CyclomaticComplexity



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# File 'lib/tui_td/ansi_parser.rb', line 690

def self.default_cell
  { char: " ", fg: "default", bg: "default", bold: false, italic: false, underline: false, blink: false }
end

.parse(raw, rows = 40, cols = 120) ⇒ Object

Parse raw terminal output into a structured state Hash rubocop:disable Metrics/AbcSize, Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity, Metrics/BlockNesting



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# File 'lib/tui_td/ansi_parser.rb', line 120

def self.parse(raw, rows = 40, cols = 120)
  grid = Array.new(rows) do
    Array.new(cols) { default_cell.dup }
  end

  cursor = { row: 0, col: 0 }
  attrs = { fg: "default", bg: "default", bold: false, italic: false, underline: false, blink: false }
  saved_cursor = nil
  scroll_region = { top: 0, bottom: rows - 1 }
  pending_dsr = false

  normal_grid = grid
  alt_grid = nil

  normal_cursor = cursor
  alt_cursor = { row: 0, col: 0 }

  normal_saved_cursor = nil
  alt_saved_cursor = nil

  use_alt_screen = false

  cursor_visible = true
  cursor_style = 1 # 1 = blinking block (default)

  g0_charset = :ascii
  g1_charset = :dec
  active_charset = :g0

  mouse_mode = :none
  mouse_format = :normal

  # Strip everything before the last full clear (if any)
  # to avoid accumulated garbage
  processed = raw

  i = 0
  while i < processed.length
    if processed[i] == "\e" && processed[i + 1] == "["
      # Find end of CSI sequence
      j = i + 2
      j += 1 while j < processed.length && !processed[j].match?(/[A-HJ-KP-SX@`fhlmnRrsuq]/)
      seq = processed[i..j]

      dsr, new_saved, action = _apply_csi(seq, cursor, attrs, grid, rows, cols, saved_cursor, scroll_region)
      pending_dsr ||= dsr

      if new_saved
        if use_alt_screen
          alt_saved_cursor = new_saved
          saved_cursor = alt_saved_cursor
        else
          normal_saved_cursor = new_saved
          saved_cursor = normal_saved_cursor
        end
      end

      if action.key?(:alt_screen)
        new_alt = action[:alt_screen]
        code = action[:alt_screen_code]
        if new_alt != use_alt_screen
          if new_alt
            # Switch to Alternate Screen
            # Save normal cursor
            normal_cursor = { row: cursor[:row], col: cursor[:col] }

            # Lazy initialize alt grid
            alt_grid ||= Array.new(rows) do
              Array.new(cols) { default_cell.dup }
            end

            # For \e[?1049h, clear alternate screen and reset cursor to 0,0
            if code == 1049
              alt_grid = Array.new(rows) do
                Array.new(cols) { default_cell.dup }
              end
              alt_cursor = { row: 0, col: 0 }
            end

            grid = alt_grid
            cursor = alt_cursor
            saved_cursor = alt_saved_cursor
            use_alt_screen = true
          else
            # Switch to Normal Screen
            # Save alt cursor
            alt_cursor = { row: cursor[:row], col: cursor[:col] }

            grid = normal_grid
            cursor = normal_cursor
            saved_cursor = normal_saved_cursor
            use_alt_screen = false
          end
        end
      end

      cursor_visible = action[:cursor_visible] if action.key?(:cursor_visible)

      cursor_style = action[:cursor_style] if action.key?(:cursor_style)

      mouse_mode = action[:mouse_mode] if action.key?(:mouse_mode)

      mouse_format = action[:mouse_format] if action.key?(:mouse_format)

      i = j + 1
    elsif ["\n", "\r\n"].include?(processed[i])
      cursor[:row] += 1
      cursor[:col] = 0
      i += processed[i..(i + 1)] == "\r\n" ? 2 : 1
    elsif processed[i] == "\r"
      cursor[:col] = 0
      i += 1
    elsif processed[i] == "\t"
      cursor[:col] = ((cursor[:col] / 8) + 1) * 8
      cursor[:col] = cols - 1 if cursor[:col] >= cols
      i += 1
    elsif processed[i] == "\b"
      cursor[:col] -= 1 if cursor[:col].positive?
      i += 1
    elsif processed[i] == "\a"
      # Bell — ignore
      i += 1
    elsif processed[i] == "\x0e"
      active_charset = :g1
      i += 1
    elsif processed[i] == "\x0f"
      active_charset = :g0
      i += 1
    elsif processed[i] == "\e"
      # Handle non-CSI escape sequences
      if processed[i + 1] == "7"
        # DECSC — Save Cursor
        if use_alt_screen
          alt_saved_cursor = { row: cursor[:row], col: cursor[:col] }
          saved_cursor = alt_saved_cursor
        else
          normal_saved_cursor = { row: cursor[:row], col: cursor[:col] }
          saved_cursor = normal_saved_cursor
        end
        i += 2
      elsif processed[i + 1] == "8"
        # DECRC — Restore Cursor
        if saved_cursor
          cursor[:row] = saved_cursor[:row]
          cursor[:col] = saved_cursor[:col]
        end
        i += 2
      elsif processed[i + 1] == "(" && %w[0 B].include?(processed[i + 2])
        g0_charset = (processed[i + 2] == "0" ? :dec : :ascii)
        i += 3
      elsif processed[i + 1] == ")" && %w[0 B].include?(processed[i + 2])
        g1_charset = (processed[i + 2] == "0" ? :dec : :ascii)
        i += 3
      elsif processed[i + 1]&.match?(%r{[()*+\-./]})
        # Other ISO 2022 charset sequences (e.g. G2/G3 or other charsets)
        i += 3
      else
        i += 1
      end
    elsif (char, char_len = _utf8_char_at(processed, i))
      # Printable character (including multi-byte UTF-8)
      if cursor[:row] < rows && cursor[:col] < cols
        cell = grid[cursor[:row]][cursor[:col]]
        current_charset = (active_charset == :g1 ? g1_charset : g0_charset)
        mapped_char = char
        mapped_char = DEC_MAP[char] if current_charset == :dec && DEC_MAP.key?(char)
        cell[:char] = mapped_char
        cell.merge!(attrs)
        cursor[:col] += 1
        cursor[:col] = cols - 1 if cursor[:col] >= cols
      end
      i += char_len
    else # rubocop:disable Lint/DuplicateBranch
      i += 1
    end

    # Handle scrolling within the defined scroll region
    region_top = scroll_region[:top]
    region_bottom = scroll_region[:bottom]

    next unless cursor[:row] > region_bottom

    scroll_lines = [cursor[:row] - region_bottom, rows].min
    # Shift lines within the scroll region up
    (region_top..(region_bottom - scroll_lines)).each do |ri|
      src = ri + scroll_lines
      grid[ri] = src <= region_bottom ? grid[src] : Array.new(cols) { default_cell.dup }
    end
    # Fill bottom of scroll region with blank lines
    ((region_bottom - scroll_lines + 1)..region_bottom).each do |ri|
      grid[ri] = Array.new(cols) { default_cell.dup }
    end
    cursor[:row] = region_bottom
  end

  {
    size: { rows: rows, cols: cols },
    cursor: {
      row: cursor[:row],
      col: cursor[:col],
      visible: cursor_visible,
      style: cursor_style,
    },
    rows: grid,
    pending_dsr: pending_dsr,
    cursor_visible: cursor_visible,
    cursor_style: cursor_style,
    mouse_mode: mouse_mode,
    mouse_format: mouse_format,
  }
end