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}

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

Class Method Summary collapse

Class Method Details

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



230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
 
# File 'lib/tui_td/ansi_parser.rb', line 230

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@`fhlmnRrsu])$/)
  return [false, nil] unless match

  params = match[1].split(";").map(&:to_i)
  command = match[2]

  new_saved = nil

  case command
  when "m"
    _apply_sgr(params, attrs)
  when "A" # CUU — Cursor Up
    n = params[0] || 1
    n = 1 if n == 0
    cursor[:row] = [cursor[:row] - n, 0].max
  when "B" # CUD — Cursor Down
    n = params[0] || 1
    n = 1 if n == 0
    cursor[:row] = [cursor[:row] + n, rows - 1].min
  when "C" # CUF — Cursor Forward
    n = params[0] || 1
    n = 1 if n == 0
    cursor[:col] = [cursor[:col] + n, cols - 1].min
  when "D" # CUB — Cursor Back
    n = params[0] || 1
    n = 1 if n == 0
    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", "l" # DEC private mode set/reset — skip
    nil
  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]
end

._apply_sgr(params, attrs) ⇒ Object 



323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
 
# File 'lib/tui_td/ansi_parser.rb', line 323

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

  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)
    when 1
      attrs[:bold] = true
    when 3
      attrs[:italic] = true
    when 4
      attrs[:underline] = true
    when 22
      attrs[:bold] = false
    when 23
      attrs[:italic] = false
    when 24
      attrs[:underline] = false
    when 7
      # Reverse — swap fg and bg
      attrs[:fg], attrs[:bg] = attrs[:bg], attrs[:fg]
    when 27
      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, g, b = params[i + 2], params[i + 3], params[i + 4]
        attrs[:fg] = format("#%02x%02x%02x", r, g, 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, g, b = params[i + 2], params[i + 3], params[i + 4]
        attrs[:bg] = format("#%02x%02x%02x", r, g, 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 



437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
 
# File 'lib/tui_td/ansi_parser.rb', line 437

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

._erase_all(grid, rows, cols) ⇒ Object 



414
415
416
417
418
 
# File 'lib/tui_td/ansi_parser.rb', line 414

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 



388
389
390
391
392
393
394
395
396
397
398
399
 
# File 'lib/tui_td/ansi_parser.rb', line 388

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 



432
433
434
435
 
# File 'lib/tui_td/ansi_parser.rb', line 432

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 



426
427
428
429
430
 
# File 'lib/tui_td/ansi_parser.rb', line 426

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 



420
421
422
423
424
 
# File 'lib/tui_td/ansi_parser.rb', line 420

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 



401
402
403
404
405
406
407
408
409
410
411
412
 
# File 'lib/tui_td/ansi_parser.rb', line 401

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.



461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
 
# File 'lib/tui_td/ansi_parser.rb', line 461

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)



190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
 
# File 'lib/tui_td/ansi_parser.rb', line 190

def self.build_frame(state)
  rows = state.dig(:size, :rows) || state["size"]["rows"]
  cols = state.dig(:size, :cols) || state["size"]["cols"]
  grid = state[:rows] || state["rows"]
  cursor = state[:cursor] || state["cursor"]

  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

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

      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

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

.default_cell ⇒ Object 



455
456
457
 
# File 'lib/tui_td/ansi_parser.rb', line 455

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

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

Parse raw terminal output into a structured state Hash



84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
 
# File 'lib/tui_td/ansi_parser.rb', line 84

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 }
  saved_cursor = nil
  scroll_region = { top: 0, bottom: rows - 1 }
  pending_dsr = false

  # 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@`fhlmnRrsu]/)
      seq = processed[i..j]

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

      i = j + 1
    elsif processed[i] == "\n" || processed[i] == "\r\n"
      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] > 0
      i += 1
    elsif processed[i] == "\a"
      # Bell — ignore
      i += 1
    elsif processed[i] == "\e"
      # Handle non-CSI escape sequences
      if processed[i + 1] == "7"
        # DECSC — Save Cursor
        saved_cursor = { row: cursor[:row], col: cursor[:col] }
        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] && processed[i + 1].match?(/[()*+\-.\/]/)
        # ISO 2022 charset: \e( B  \e) 0  etc. (3 chars total)
        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]]
        cell[:char] = char
        cell.merge!(attrs)
        cursor[:col] += 1
        cursor[:col] = cols - 1 if cursor[:col] >= cols
      end
      i += char_len
    else
      i += 1
    end

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

    if 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
  end

  {
    size: { rows: rows, cols: cols },
    cursor: cursor,
    rows: grid,
    pending_dsr: pending_dsr,
  }
end