1 /* $XTermId: scrollback.c,v 1.21 2020/10/12 19:22:13 tom Exp $ */
2
3 /*
4 * Copyright 2009-2019,2020 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 #include <xterm.h>
34
35 #define REAL_ROW(screen, row) ((row) + (screen)->saved_fifo)
36 #define ROW2FIFO(screen, row) \
37 (unsigned) (REAL_ROW(screen, row) % (screen)->savelines)
38
39 /*
40 * Given a row-number, find the corresponding data for the line in the VT100
41 * widget's saved-line FIFO. The row-number (from getLineData) is negative.
42 * So we just count backwards from the last saved line.
43 */
44 LineData *
getScrollback(TScreen * screen,int row)45 getScrollback(TScreen *screen, int row)
46 {
47 LineData *result = 0;
48
49 if (screen->saved_fifo > 0 && REAL_ROW(screen, row) >= 0) {
50 unsigned which = ROW2FIFO(screen, row);
51 ScrnBuf where = scrnHeadAddr(screen, screen->saveBuf_index, which);
52 result = (LineData *) where;
53 }
54
55 TRACE(("getScrollback %d -> %d -> %p\n",
56 row, ROW2FIFO(screen, row),
57 (void *) result));
58 return result;
59 }
60
61 /*
62 * Allocate a new row in the scrollback FIFO, returning a pointer to it.
63 */
64 LineData *
addScrollback(TScreen * screen)65 addScrollback(TScreen *screen)
66 {
67 ScrnBuf where = 0;
68 unsigned ncols = (unsigned) MaxCols(screen);
69
70 if (screen->saveBuf_index != 0 && screen->savelines != 0) {
71 unsigned which;
72 Char *block;
73
74 TRACE(("addScrollback %lu\n", screen->saved_fifo));
75
76 /* first, see which index we'll use */
77 which = (unsigned) (screen->saved_fifo % screen->savelines);
78 where = scrnHeadAddr(screen, screen->saveBuf_index, which);
79
80 /* discard any obsolete index data */
81 if (screen->saved_fifo > screen->savelines) {
82 LineData *prior = (LineData *) where;
83 /*
84 * setupLineData uses the attribs as the first address used from the
85 * data block.
86 */
87 if (prior->attribs != 0) {
88 TRACE(("...freeing prior FIFO data in slot %d: %p->%p\n",
89 which, (void *) prior, (void *) prior->attribs));
90 FreeAndNull(prior->attribs);
91 }
92 if (screen->saved_fifo > 2 * screen->savelines) {
93 screen->saved_fifo -= screen->savelines;
94 }
95 }
96
97 /* allocate the new data */
98 block = allocScrnData(screen, 1, ncols);
99
100 /* record the new data in the index */
101 setupLineData(screen, where, (Char *) block, 1, ncols);
102
103 TRACE(("...storing new FIFO data in slot %d: %p->%p\n",
104 which, (void *) where, block));
105
106 screen->saved_fifo++;
107 }
108 return (LineData *) where;
109 }
110
111 void
deleteScrollback(TScreen * screen)112 deleteScrollback(TScreen *screen)
113 {
114 unsigned which = ROW2FIFO(screen, -1);
115 ScrnBuf where = scrnHeadAddr(screen, screen->saveBuf_index, which);
116 LineData *prior = (LineData *) where;
117 /*
118 * setupLineData uses the attribs as the first address used from the
119 * data block.
120 */
121 if (prior->attribs != 0) {
122 TRACE(("...freeing prior FIFO data in slot %d: %p->%p\n",
123 which, (void *) prior, (void *) prior->attribs));
124 FreeAndNull(prior->attribs);
125 }
126 screen->saved_fifo--;
127 }
128