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      1 /* $XTermId: tabs.c,v 1.47 2019/11/13 23:19:01 tom Exp $ */
      2 
      3 /*
      4  * Copyright 2000-2018,2019 by Thomas E. Dickey
      5  *
      6  *                         All Rights Reserved
      7  *
      8  * Permission is hereby granted, free of charge, to any person obtaining a
      9  * copy of this software and associated documentation files (the
     10  * "Software"), to deal in the Software without restriction, including
     11  * without limitation the rights to use, copy, modify, merge, publish,
     12  * distribute, sublicense, and/or sell copies of the Software, and to
     13  * permit persons to whom the Software is furnished to do so, subject to
     14  * the following conditions:
     15  *
     16  * The above copyright notice and this permission notice shall be included
     17  * in all copies or substantial portions of the Software.
     18  *
     19  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
     20  * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
     21  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
     22  * IN NO EVENT SHALL THE ABOVE LISTED COPYRIGHT HOLDER(S) BE LIABLE FOR ANY
     23  * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
     24  * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
     25  * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
     26  *
     27  * Except as contained in this notice, the name(s) of the above copyright
     28  * holders shall not be used in advertising or otherwise to promote the
     29  * sale, use or other dealings in this Software without prior written
     30  * authorization.
     31  *
     32  *
     33  * Copyright 1987 by Digital Equipment Corporation, Maynard, Massachusetts.
     34  *
     35  *                         All Rights Reserved
     36  *
     37  * Permission to use, copy, modify, and distribute this software and its
     38  * documentation for any purpose and without fee is hereby granted,
     39  * provided that the above copyright notice appear in all copies and that
     40  * both that copyright notice and this permission notice appear in
     41  * supporting documentation, and that the name of Digital Equipment
     42  * Corporation not be used in advertising or publicity pertaining to
     43  * distribution of the software without specific, written prior permission.
     44  *
     45  *
     46  * DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
     47  * ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
     48  * DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR
     49  * ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
     50  * WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
     51  * ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
     52  * SOFTWARE.
     53  */
     54 
     55 /* tabs.c */
     56 
     57 #include <xterm.h>
     58 #include <data.h>
     59 
     60 #define TAB_INDEX(n) ((n) >> TAB_BITS_SHIFT)
     61 #define TAB_MASK(n)  (1U << ((n) & (TAB_BITS_WIDTH-1)))
     62 
     63 #define SET_TAB(tabs,n) UIntSet(tabs[TAB_INDEX(n)], TAB_MASK(n))
     64 #define CLR_TAB(tabs,n) UIntClr(tabs[TAB_INDEX(n)], TAB_MASK(n))
     65 #define TST_TAB(tabs,n) (tabs[TAB_INDEX(n)] & (unsigned) TAB_MASK(n))
     66 
     67 /*
     68  * places tabstops at only every 8 columns
     69  */
     70 void
     71 TabReset(Tabs tabs)
     72 {
     73     int i;
     74 
     75     TabZonk(tabs);
     76 
     77     for (i = 0; i < MAX_TABS; i += 8)
     78 	TabSet(tabs, i);
     79 }
     80 
     81 /*
     82  * places a tabstop at col
     83  */
     84 void
     85 TabSet(Tabs tabs, int col)
     86 {
     87     if (OkTAB(col)) {
     88 	SET_TAB(tabs, col);
     89     }
     90 }
     91 
     92 /*
     93  * clears a tabstop at col
     94  */
     95 void
     96 TabClear(Tabs tabs, int col)
     97 {
     98     if (OkTAB(col)) {
     99 	CLR_TAB(tabs, col);
    100     }
    101 }
    102 
    103 /*
    104  * returns the column of the next tabstop
    105  * (or MAX_TABS - 1 if there are no more).
    106  * A tabstop at col is ignored.
    107  */
    108 static int
    109 TabNext(XtermWidget xw, Tabs tabs, int col)
    110 {
    111     TScreen *screen = TScreenOf(xw);
    112 
    113     if (screen->curses && screen->do_wrap && (xw->flags & WRAPAROUND)) {
    114 	xtermIndex(xw, 1);
    115 	set_cur_col(screen, 0);
    116 	col = 0;
    117 	ResetWrap(screen);
    118     }
    119     for (++col; col < MAX_TABS; ++col)
    120 	if (TST_TAB(tabs, col))
    121 	    return (col);
    122 
    123     return (MAX_TABS - 1);
    124 }
    125 
    126 /*
    127  * returns the column of the previous tabstop
    128  * (or 0 if there are no more).
    129  * A tabstop at col is ignored.
    130  */
    131 static int
    132 TabPrev(Tabs tabs, int col)
    133 {
    134     for (--col; col >= 0; --col)
    135 	if ((col < MAX_TABS) && TST_TAB(tabs, col))
    136 	    return (col);
    137 
    138     return (0);
    139 }
    140 
    141 /*
    142  * Tab to the next stop, returning true if the cursor moved
    143  */
    144 Bool
    145 TabToNextStop(XtermWidget xw)
    146 {
    147     TScreen *screen = TScreenOf(xw);
    148     int saved_column = screen->cur_col;
    149     int next = TabNext(xw, xw->tabs, screen->cur_col);
    150     int max = LineMaxCol(screen, getLineData(screen, screen->cur_row));
    151 
    152     if (IsLeftRightMode(xw))
    153 	max = TScreenOf(xw)->rgt_marg;
    154     if (next > max)
    155 	next = max;
    156     set_cur_col(screen, next);
    157 
    158     return (screen->cur_col > saved_column);
    159 }
    160 
    161 /*
    162  * Tab to the previous stop, returning true if the cursor moved
    163  */
    164 Bool
    165 TabToPrevStop(XtermWidget xw)
    166 {
    167     TScreen *screen = TScreenOf(xw);
    168     int saved_column = screen->cur_col;
    169     int next_column = TabPrev(xw->tabs, screen->cur_col);
    170 
    171     if (xw->flags & ORIGIN) {
    172 	int left = ScrnLeftMargin(xw);
    173 	if (next_column < left)
    174 	    next_column = left;
    175     }
    176 
    177     set_cur_col(screen, next_column);
    178 
    179     return (screen->cur_col < saved_column);
    180 }
    181 
    182 /*
    183  * clears all tabs
    184  */
    185 void
    186 TabZonk(Tabs tabs)
    187 {
    188     memset(tabs, 0, sizeof(*tabs) * TAB_ARRAY_SIZE);
    189 }
    190 
    191 /*
    192  * Check if a tab is set for the given column
    193  */
    194 Bool
    195 TabIsSet(Tabs tabs, int col)
    196 {
    197     return TST_TAB(tabs, col) ? True : False;
    198 }
    199