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Diffstat (limited to 'lib/libcurses/lib_scroll.c')
| -rw-r--r-- | lib/libcurses/lib_scroll.c | 110 |
1 files changed, 110 insertions, 0 deletions
diff --git a/lib/libcurses/lib_scroll.c b/lib/libcurses/lib_scroll.c new file mode 100644 index 00000000000..d8350a38344 --- /dev/null +++ b/lib/libcurses/lib_scroll.c @@ -0,0 +1,110 @@ + +/*************************************************************************** +* COPYRIGHT NOTICE * +**************************************************************************** +* ncurses is copyright (C) 1992-1995 * +* Zeyd M. Ben-Halim * +* zmbenhal@netcom.com * +* Eric S. Raymond * +* esr@snark.thyrsus.com * +* * +* Permission is hereby granted to reproduce and distribute ncurses * +* by any means and for any fee, whether alone or as part of a * +* larger distribution, in source or in binary form, PROVIDED * +* this notice is included with any such distribution, and is not * +* removed from any of its header files. Mention of ncurses in any * +* applications linked with it is highly appreciated. * +* * +* ncurses comes AS IS with no warranty, implied or expressed. * +* * +***************************************************************************/ + + + +/* +** lib_scroll.c +** +** The routine wscrl(win, n). +** positive n scroll the window up (ie. move lines down) +** negative n scroll the window down (ie. move lines up) +** +*/ + +#include "curses.priv.h" +#include <stdlib.h> +#include <string.h> + +void _nc_scroll_window(WINDOW *win, int const n, short const top, short const bottom) +{ +int line, j; +chtype blank = _nc_render(win, ' ', BLANK); + + TR(TRACE_MOVE, ("_nc_scroll_window(%p, %d, %d, %d)", win, n, top,bottom)); + + /* + * This used to do a line-text pointer-shuffle instead of text copies. + * That (a) doesn't work when the window is derived and doesn't have + * its own storage, (b) doesn't save you a lot on modern machines + * anyway. Your typical memcpy implementations are coded in + * assembler using a tight BLT loop; for the size of copies we're + * talking here, the total execution time is dominated by the one-time + * setup cost. So there is no point in trying to be excessively + * clever -- esr. + */ + + /* shift n lines downwards */ + if (n < 0) { + for (line = bottom; line >= top-n; line--) { + memcpy(win->_line[line].text, + win->_line[line+n].text, + (size_t)(sizeof(chtype) * (win->_maxx+1))); + win->_line[line].oldindex = win->_line[line+n].oldindex; + } + for (line = top; line < top-n; line++) { + for (j = 0; j <= win->_maxx; j ++) + win->_line[line].text[j] = blank; + win->_line[line].oldindex = _NEWINDEX; + win->_line[line].firstchar = 0; + win->_line[line].lastchar = win->_maxx; + } + } + + /* shift n lines upwards */ + if (n > 0) { + for (line = top; line <= bottom-n; line++) { + memcpy(win->_line[line].text, + win->_line[line+n].text, + (size_t)(sizeof(chtype) * (win->_maxx+1))); + win->_line[line].oldindex = win->_line[line+n].oldindex; + } + for (line = bottom; line > bottom-n; line--) { + for (j = 0; j <= win->_maxx; j ++) + win->_line[line].text[j] = blank; + win->_line[line].oldindex = _NEWINDEX; + win->_line[line].firstchar = 0; + win->_line[line].lastchar = win->_maxx; + } + } +} + +int +wscrl(WINDOW *win, int n) +{ + T(("wscrl(%p,%d) called", win, n)); + + if (! win->_scroll) + return ERR; + + if (n == 0) + return OK; + + if ((n > (win->_regbottom - win->_regtop)) || + (-n > (win->_regbottom - win->_regtop))) + return ERR; + + _nc_scroll_window(win, n, win->_regtop, win->_regbottom); + touchline(win, win->_regtop, (int)(win->_regbottom - win->_regtop + 1)); + + _nc_synchook(win); + return OK; +} |