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 */
70void
71TabReset(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 */
84void
85TabSet(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 */
95void
96TabClear(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 */
108static int
109TabNext(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 */
131static int
132TabPrev(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 */
144Bool
145TabToNextStop(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 */
164Bool
165TabToPrevStop(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 */
185void
186TabZonk(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 */
194Bool
195TabIsSet(Tabs tabs, int col)
196{
197    return TST_TAB(tabs, col) ? True : False;
198}
199