Add tab handling

Support setting (HTS & DECST8C) and clearing (TBC) tabs, overriding the
console's own tab processing.  I've extended TBC with `\e[8g` to restore
console processing and added an extra parameter to DECST8C to set a
particular tab size.

ANSI.c

@@ -169,7 +169,8 @@
     added IND, NEL & RI (using buffer, in keeping with LF);
     added DA, DECCOLM, DECNCSM, DECSC & DECRC;
     an explicit zero parameter should still default to one;
-    restrict parameters to a maximum value of 32767.
+    restrict parameters to a maximum value of 32767;
+    added tab handling.
 */
 
 #include "ansicon.h"
@@ -199,7 +200,8 @@ struct Cache
 } cache[CACHE];
 
 #define ESC	'\x1B'          // ESCape character
-#define BEL	'\x07'
+#define BEL	'\x07'          // BELl
+#define HT	'\x09'          // Horizontal Tabulation
 #define SO	'\x0E'          // Shift Out
 #define SI	'\x0F'          // Shift In
 
@@ -334,6 +336,8 @@ typedef BOOL (WINAPI *PHCSBIX)(
 PHCSBIX GetConsoleScreenBufferInfoX, SetConsoleScreenBufferInfoX;
 
 
+#define MAX_TABS 2048
+
 typedef struct
 {
   BYTE	   foreground;	// ANSI base color (0 to 7; add 30)
@@ -349,6 +353,8 @@ typedef struct
   SHORT    buf_width;	// buffer width prior to setting 132 columns
   SHORT    win_width;	// window width prior to setting 132 columns
   BYTE	   noclear;	// don't clear the screen on column mode change
+  BYTE	   tabs;	// handle tabs directly
+  BYTE	   tab_stop[MAX_TABS];
 } STATE, *PSTATE;
 
 PSTATE pState;
@@ -704,6 +710,19 @@ void send_palette_sequence( COLORREF c )
   SendSequence( buf );
 }
 
+
+// Clear existing tabs and set tab stops at every size columns.
+void init_tabs( int size )
+{
+  int i;
+
+  memset( pState->tab_stop, FALSE, MAX_TABS );
+  for (i = 0; i < MAX_TABS; i += size)
+    pState->tab_stop[i] = TRUE;
+  pState->tabs = TRUE;
+}
+
+
 // ========== Print functions
 
 //-----------------------------------------------------------------------------
@@ -751,8 +770,11 @@ void InterpretEscSeq( void )
 
   if (prefix == '[')
   {
-    if (prefix2 == '?' && (suffix == 'h' || suffix == 'l') && es_argc == 1)
+    if (prefix2 == '?')
     {
+      if (suffix == 'h' || suffix == 'l')
+      {
+	if (es_argc != 1) return;
 	switch (es_argv[0])
 	{
 	  case 25:
@@ -826,6 +848,14 @@ void InterpretEscSeq( void )
 	  }
 	}
       }
+      else if (suffix == 'W')
+      {
+	if (es_argv[0] != 5 || es_argc > 2) return;
+	if (es_argc == 1) es_argv[1] = 8;
+	init_tabs( es_argv[1] );
+	return;
+      }
+    }
     // Ignore any other private sequences.
     if (prefix2 != 0)
       return;
@@ -1185,9 +1215,37 @@ void InterpretEscSeq( void )
 	SetConsoleCursorPosition( hConOut, Pos );
       return;
 
+      case 'g':
+	if (es_argc > 1) return; // ESC[g == ESC[0g
+	switch (es_argv[0])
+	{
+	  case 0: // ESC[0g Clear tab at cursor
+	    if (!pState->tabs) init_tabs( 8 );
+	    if (CUR.X < MAX_TABS) pState->tab_stop[CUR.X] = FALSE;
+	  return;
+
+	  case 3: // ESC[3g Clear all tabs
+	    memset( pState->tab_stop, FALSE, MAX_TABS );
+	    pState->tabs = TRUE;
+	  return;
+
+	  case 8: // ESC[8g Let console handle tabs
+	    pState->tabs = FALSE;
+	  return;
+
+	  default:
+	  return;
+	}
+
       case 'I': // ESC[#I Moves cursor forward # tabs
 	if (es_argc > 1) return; // ESC[I == ESC[1I
 	Pos.Y = CUR.Y;
+	if (pState->tabs)
+	{
+	  Pos.X = CUR.X;
+	  while (++Pos.X < MAX_TABS && (!pState->tab_stop[Pos.X] || --p1 > 0)) ;
+	}
+	else
 	  Pos.X = (CUR.X & -8) + p1 * 8;
 	if (Pos.X > RIGHT) Pos.X = RIGHT;
 	SetConsoleCursorPosition( hConOut, Pos );
@@ -1196,10 +1254,18 @@ void InterpretEscSeq( void )
       case 'Z': // ESC[#Z Moves cursor back # tabs
 	if (es_argc > 1) return; // ESC[Z == ESC[1Z
 	Pos.Y = CUR.Y;
+	if (pState->tabs)
+	{
+	  Pos.X = (CUR.X < MAX_TABS) ? CUR.X : MAX_TABS;
+	  while (--Pos.X > 0 && (!pState->tab_stop[Pos.X] || --p1 > 0)) ;
+	}
+	else
+	{
 	  if ((CUR.X & 7) == 0)
 	     Pos.X = CUR.X - p1 * 8;
 	  else
 	     Pos.X = (CUR.X & -8) - (p1 - 1) * 8;
+	}
 	if (Pos.X < LEFT) Pos.X = LEFT;
 	SetConsoleCursorPosition( hConOut, Pos );
       return;
@@ -1579,6 +1645,15 @@ ParseAndPrintString( HANDLE hDev,
       }
       else if (c == SO) shifted = TRUE;
       else if (c == SI) shifted = G0_special;
+      else if (c == HT && pState != NULL && pState->tabs)
+      {
+	CONSOLE_SCREEN_BUFFER_INFO Info;
+	FlushBuffer();
+	GetConsoleScreenBufferInfo( hConOut, &Info );
+	while (++CUR.X < MAX_TABS && !pState->tab_stop[CUR.X]) ;
+	if (CUR.X > RIGHT) CUR.X = RIGHT;
+	SetConsoleCursorPosition( hConOut, CUR );
+      }
       else PushBuffer( (WCHAR)c );
     }
     else if (state == 2)
@@ -1622,6 +1697,15 @@ ParseAndPrintString( HANDLE hDev,
 	ScrollUp();
         state = 1;
       }
+      else if (c == 'H')        // HTS Character Tabulation Set
+      {
+	CONSOLE_SCREEN_BUFFER_INFO Info;
+	if (!pState->tabs) init_tabs( 8 );
+	FlushBuffer();
+	GetConsoleScreenBufferInfo( hConOut, &Info );
+	if (CUR.X < MAX_TABS) pState->tab_stop[CUR.X] = TRUE;
+	state = 1;
+      }
       else if (c == '7' ||      // DECSC Save Cursor
 	       c == '8')        // DECRC Restore Cursor
       {

ansicon.c

@@ -91,7 +91,7 @@
     use -pu to unload from the parent.
 */
 
-#define PDATE L"9 December, 2017"
+#define PDATE L"10 December, 2017"
 
 #include "ansicon.h"
 #include "version.h"

readme.txt

@@ -150,7 +150,8 @@ Usage
 Sequences Recognised
 ====================
 
-    The following escape sequences are recognised.
+    The following escape sequences are recognised (see "sequences.txt" for a
+    more complete description).
 
 	\e]0;titleBEL		xterm: Set window's title (and icon, ignored)
 	\e]2;titleBEL		xterm: Set window's title
@@ -183,6 +184,8 @@ Sequences Recognised
 	\e[#;#;#...,~	DECPS	DEC Play Sound
 	\e8		DECRC	DEC Restore Cursor
 	\e7		DECSC	DEC Save Cursor
+	\e[?5W		DECST8C DEC Set Tab at Every 8 Columns
+	\e[?5;#W	DECST8C DEC Set Tab at Every # Columns (ANSICON extension)
 	\e[?25h 	DECTCEM DEC Text Cursor Enable Mode (show cursor)
 	\e[?25l 	DECTCEM DEC Text Cursor Enable Mode (hide cursor)
 	\e[#M		DL	Delete Line
@@ -193,6 +196,8 @@ Sequences Recognised
 	\e[#`		HPA	Character Position Absolute
 	\e[#j		HPB	Character Position Backward
 	\e[#a		HPR	Character Position Forward
+	HT		HT	Character Tabulation
+	\eH		HTS	Character Tabulation Set
 	\e[#;#f 	HVP	Character And Line Position
 	\e[#@		ICH	Insert Character
 	\e[#L		IL	Insert Line
@@ -205,13 +210,14 @@ Sequences Recognised
 	\e(0		SCS	Select Character Set (DEC special graphics)
 	\e(B		SCS	Select Character Set (ASCII)
 	\e[#;#;#m	SGR	Select Graphic Rendition
+	\e[#g		TBC	Tabulation Clear
 	\e[#d		VPA	Line Position Absolute
 	\e[#k		VPB	Line Position Backward
 	\e[#e		VPR	Line Position Forward
 
     '\e' represents the escape character (ASCII 27); '#' represents a decimal
-    number (optional, in most cases defaulting to 1); BEL, SO and SI are ASCII
+    number (optional, in most cases defaulting to 1); BEL, HT, SO and SI are
-    7, 14 and 15.  See "sequences.txt" for a more complete description.
+    ASCII 7, 9, 14 and 15.
 
     Escape followed by a control character will display that character, not
     perform its function; an unrecognised character will preserve the escape.
@@ -286,7 +292,7 @@ DEC Special Graphics Character Set
 Limitations
 ===========
 
-    Tabs are fixed at eight columns.
+    Tabs can only be set up to column 2048.
     The saved position will not be restored correctly if the buffer scrolls.
     Palette sequences only work from Vista.
 
@@ -304,7 +310,7 @@ Version History
 
     Legend: + added, - bug-fixed, * changed.
 
-    1.80 - 9 December, 2017:
+    1.80 - 10 December, 2017:
     - fix unloading;
     - fix -e et al when redirecting to CON;
     - hook CreateFile and CreateConsoleScreenBuffer to force read/write access
@@ -323,7 +329,8 @@ Version History
     + added palette sequences;
     + added -pu to unload from the parent;
     + added IND, NEL, RI, DA, DECCOLM, DECNCSM, DECSC & DECRC;
-    + added SCS, but only for special/ASCII (same as Win10).
+    + added SCS, but only for special/ASCII (same as Win10);
+    + added tab handling (HT, HTS, TBC & DECST8C).
 
     1.72 - 24 December, 2015:
     - handle STD_OUTPUT_HANDLE & STD_ERROR_HANDLE in WriteFile;
@@ -551,5 +558,5 @@ Distribution
     in LICENSE.txt.
 
 
-============================
+==============================
-Jason Hood, 9 December, 2017.
+Jason Hood, 10 December, 2017.

sequences.txt

@@ -83,6 +83,14 @@ M	move cursor up one line (scroll if necessary; always uses buffer)
 [#C	move cursor right # characters
 [D	move cursor left one character
 [#D	move cursor left # characters
+
+H	set tab stop
+[g	remove tab stop at cursor
+[0g	as above
+[3g	remove all tab stops
+[8g	restore console tab handling (ANSICON extension)
+[?5W	set tab stops every 8 columns
+[?5;#W	set tab stops every # columns (ANSICON extension)
 [I	move cursor forward one tab
 [#I	move cursor forward # tabs
 [Z	move cursor back one tab