1 /* $OpenBSD: lib_scroll.c,v 1.3 2001/01/22 18:01:43 millert Exp $ */ 2 3 /**************************************************************************** 4 * Copyright (c) 1998,2000 Free Software Foundation, Inc. * 5 * * 6 * Permission is hereby granted, free of charge, to any person obtaining a * 7 * copy of this software and associated documentation files (the * 8 * "Software"), to deal in the Software without restriction, including * 9 * without limitation the rights to use, copy, modify, merge, publish, * 10 * distribute, distribute with modifications, sublicense, and/or sell * 11 * copies of the Software, and to permit persons to whom the Software is * 12 * furnished to do so, subject to the following conditions: * 13 * * 14 * The above copyright notice and this permission notice shall be included * 15 * in all copies or substantial portions of the Software. * 16 * * 17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS * 18 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF * 19 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. * 20 * IN NO EVENT SHALL THE ABOVE COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, * 21 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR * 22 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR * 23 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. * 24 * * 25 * Except as contained in this notice, the name(s) of the above copyright * 26 * holders shall not be used in advertising or otherwise to promote the * 27 * sale, use or other dealings in this Software without prior written * 28 * authorization. * 29 ****************************************************************************/ 30 31 /**************************************************************************** 32 * Author: 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("$From: lib_scroll.c,v 1.20 2000/12/10 02:54:03 tom Exp $") 48 49 NCURSES_EXPORT(void) 50 _nc_scroll_window 51 (WINDOW *win, int const n, NCURSES_SIZE_T const top, 52 NCURSES_SIZE_T const bottom, chtype blank) 53 { 54 int line, j; 55 size_t to_copy = (size_t) (sizeof(chtype) * (win->_maxx + 1)); 56 57 TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %d, %d)", win, n, top, bottom)); 58 59 /* 60 * This used to do a line-text pointer-shuffle instead of text copies. 61 * That (a) doesn't work when the window is derived and doesn't have 62 * its own storage, (b) doesn't save you a lot on modern machines 63 * anyway. Your typical memcpy implementations are coded in 64 * assembler using a tight BLT loop; for the size of copies we're 65 * talking here, the total execution time is dominated by the one-time 66 * setup cost. So there is no point in trying to be excessively 67 * clever -- esr. 68 */ 69 70 /* shift n lines downwards */ 71 if (n < 0) { 72 for (line = bottom; line >= top - n; line--) { 73 memcpy(win->_line[line].text, 74 win->_line[line + n].text, 75 to_copy); 76 if_USE_SCROLL_HINTS( 77 win->_line[line].oldindex = 78 win->_line[line + n].oldindex); 79 } 80 for (line = top; line < top - n; line++) { 81 for (j = 0; j <= win->_maxx; j++) 82 win->_line[line].text[j] = blank; 83 if_USE_SCROLL_HINTS(win->_line[line].oldindex = _NEWINDEX); 84 } 85 } 86 87 /* shift n lines upwards */ 88 if (n > 0) { 89 for (line = top; line <= bottom - n; line++) { 90 memcpy(win->_line[line].text, 91 win->_line[line + n].text, 92 to_copy); 93 if_USE_SCROLL_HINTS(win->_line[line].oldindex = 94 win->_line[line + n].oldindex); 95 } 96 for (line = bottom; line > bottom - n; 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 touchline(win, top, bottom - top + 1); 103 } 104 105 NCURSES_EXPORT(int) 106 wscrl(WINDOW *win, int n) 107 { 108 T((T_CALLED("wscrl(%p,%d)"), win, n)); 109 110 if (!win || !win->_scroll) 111 returnCode(ERR); 112 113 if (n == 0) 114 returnCode(OK); 115 116 if ((n > (win->_regbottom - win->_regtop)) || 117 (-n > (win->_regbottom - win->_regtop))) 118 returnCode(ERR); 119 120 _nc_scroll_window(win, n, win->_regtop, win->_regbottom, _nc_background(win)); 121 122 _nc_synchook(win); 123 returnCode(OK); 124 } 125