1 /**************************************************************************** 2 * Copyright 2019,2020 Thomas E. Dickey * 3 * Copyright 1998-2010,2011 Free Software Foundation, Inc. * 4 * * 5 * Permission is hereby granted, free of charge, to any person obtaining a * 6 * copy of this software and associated documentation files (the * 7 * "Software"), to deal in the Software without restriction, including * 8 * without limitation the rights to use, copy, modify, merge, publish, * 9 * distribute, distribute with modifications, sublicense, and/or sell * 10 * copies of the Software, and to permit persons to whom the Software is * 11 * furnished to do so, subject to the following conditions: * 12 * * 13 * The above copyright notice and this permission notice shall be included * 14 * in all copies or substantial portions of the Software. * 15 * * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * 17 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * 18 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * 19 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * 20 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * 21 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * 22 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. * 23 * * 24 * Except as contained in this notice, the name(s) of the above copyright * 25 * holders shall not be used in advertising or otherwise to promote the * 26 * sale, use or other dealings in this Software without prior written * 27 * authorization. * 28 ****************************************************************************/ 29 30 /**************************************************************************** 31 * Author: Thomas E. Dickey 1996-2003 * 32 * and: Zeyd M. Ben-Halim <zmbenhal@netcom.com> 1992,1995 * 33 * and: Eric S. Raymond <esr@snark.thyrsus.com> * 34 ****************************************************************************/ 35 36 /* 37 ** lib_scroll.c 38 ** 39 ** The routine wscrl(win, n). 40 ** positive n scroll the window up (ie. move lines down) 41 ** negative n scroll the window down (ie. move lines up) 42 ** 43 */ 44 45 #include <curses.priv.h> 46 47 MODULE_ID("$Id: lib_scroll.c,v 1.32 2020/02/02 23:34:34 tom Exp $") 48 49 NCURSES_EXPORT(void) 50 _nc_scroll_window(WINDOW *win, 51 int const n, 52 int const top, 53 int const bottom, 54 NCURSES_CH_T blank) 55 { 56 int limit; 57 int line; 58 int j; 59 size_t to_copy = (sizeof(NCURSES_CH_T) * (size_t) (win->_maxx + 1)); 60 61 TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %ld, %ld)", 62 (void *) win, n, (long) top, (long) bottom)); 63 64 if (top < 0 65 || bottom < top 66 || bottom > win->_maxy) { 67 TR(TRACE_MOVE, ("nothing to scroll")); 68 return; 69 } 70 71 /* 72 * This used to do a line-text pointer-shuffle instead of text copies. 73 * That (a) doesn't work when the window is derived and doesn't have 74 * its own storage, (b) doesn't save you a lot on modern machines 75 * anyway. Your typical memcpy implementations are coded in 76 * assembler using a tight BLT loop; for the size of copies we're 77 * talking here, the total execution time is dominated by the one-time 78 * setup cost. So there is no point in trying to be excessively 79 * clever -- esr. 80 */ 81 #define BottomLimit(n) ((n) >= 0 && (n) >= top) 82 #define TopLimit(n) ((n) <= win->_maxy && (n) <= bottom) 83 84 /* shift n lines downwards */ 85 if (n < 0) { 86 limit = top - n; 87 for (line = bottom; line >= limit && BottomLimit(line); line--) { 88 TR(TRACE_MOVE, ("...copying %d to %d", line + n, line)); 89 memcpy(win->_line[line].text, 90 win->_line[line + n].text, 91 to_copy); 92 if_USE_SCROLL_HINTS(win->_line[line].oldindex = 93 win->_line[line + n].oldindex); 94 } 95 for (line = top; line < limit && TopLimit(line); line++) { 96 TR(TRACE_MOVE, ("...filling %d", line)); 97 for (j = 0; j <= win->_maxx; j++) 98 win->_line[line].text[j] = blank; 99 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX); 100 } 101 } 102 103 /* shift n lines upwards */ 104 if (n > 0) { 105 limit = bottom - n; 106 for (line = top; line <= limit && TopLimit(line); line++) { 107 memcpy(win->_line[line].text, 108 win->_line[line + n].text, 109 to_copy); 110 if_USE_SCROLL_HINTS(win->_line[line].oldindex = 111 win->_line[line + n].oldindex); 112 } 113 for (line = bottom; line > limit && BottomLimit(line); line--) { 114 for (j = 0; j <= win->_maxx; j++) 115 win->_line[line].text[j] = blank; 116 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX); 117 } 118 } 119 touchline(win, top, bottom - top + 1); 120 121 if_WIDEC({ 122 if (WINDOW_EXT(win, addch_used) != 0) { 123 int next = WINDOW_EXT(win, addch_y) + n; 124 if (next < 0 || next > win->_maxy) { 125 TR(TRACE_VIRTPUT, 126 ("Alert discarded multibyte on scroll")); 127 WINDOW_EXT(win, addch_y) = 0; 128 } else { 129 TR(TRACE_VIRTPUT, ("scrolled working position to %d,%d", 130 WINDOW_EXT(win, addch_y), 131 WINDOW_EXT(win, addch_x))); 132 WINDOW_EXT(win, addch_y) = next; 133 } 134 } 135 }) 136 } 137 138 NCURSES_EXPORT(int) 139 wscrl(WINDOW *win, int n) 140 { 141 T((T_CALLED("wscrl(%p,%d)"), (void *) win, n)); 142 143 if (!win || !win->_scroll) { 144 TR(TRACE_MOVE, ("...scrollok is false")); 145 returnCode(ERR); 146 } 147 148 if (n != 0) { 149 _nc_scroll_window(win, n, win->_regtop, win->_regbottom, win->_nc_bkgd); 150 _nc_synchook(win); 151 } 152 returnCode(OK); 153 } 154