diff options
Diffstat (limited to 'libcons/vcons-scrollback.c')
| -rw-r--r-- | libcons/vcons-scrollback.c | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/libcons/vcons-scrollback.c b/libcons/vcons-scrollback.c new file mode 100644 index 00000000..cfc94458 --- /dev/null +++ b/libcons/vcons-scrollback.c @@ -0,0 +1,122 @@ +/* vcons-scrollback.c - Move forward and backward in the scrollback buffer. + Copyright (C) 2002 Free Software Foundation, Inc. + Written by Marcus Brinkmann. + + This file is part of the GNU Hurd. + + The GNU Hurd is free software; you can redistribute it and/or + modify it under the terms of the GNU General Public License as + published by the Free Software Foundation; either version 2, or (at + your option) any later version. + + The GNU Hurd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software + Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA. */ + +#include <stdint.h> + +#include <cthreads.h> + +#include "cons.h" + +/* Scroll back into the history of VCONS by DELTA lines. */ +int +cons_vcons_scrollback (vcons_t vcons, int delta) +{ + int scrolling; + uint32_t new_scr; + + mutex_lock (&vcons->lock); + if (delta > 0 || vcons->scrolling > (uint32_t) (-delta)) + { + new_scr = vcons->scrolling + delta; + if (new_scr > vcons->state.screen.scr_lines) + new_scr = vcons->state.screen.scr_lines; + } + else + new_scr = 0; + + if (new_scr == vcons->scrolling) + { + mutex_unlock (&vcons->lock); + return 0; + } + + scrolling = vcons->scrolling - new_scr; + { + uint32_t new_cur_line; + off_t size = vcons->state.screen.width + * vcons->state.screen.lines; + off_t vis_start; + off_t start; + off_t end; + + if (vcons->state.screen.cur_line >= new_scr) + new_cur_line = vcons->state.screen.cur_line - new_scr; + else + new_cur_line = (UINT32_MAX - (new_scr - vcons->state.screen.cur_line)) + 1; + + if (scrolling > 0 && (uint32_t) scrolling > vcons->state.screen.height) + scrolling = vcons->state.screen.height; + else if (scrolling < 0 + && (uint32_t) (-scrolling) > vcons->state.screen.height) + scrolling = -vcons->state.screen.height; + if ((scrolling > 0 && scrolling < vcons->state.screen.height) + || (scrolling < 0 + && (uint32_t) (-scrolling) < vcons->state.screen.height)) + cons_vcons_scroll (vcons, scrolling); + + vis_start = vcons->state.screen.width + * (new_cur_line % vcons->state.screen.lines); + if (scrolling > 0) + start = (((new_cur_line % vcons->state.screen.lines) + + vcons->state.screen.height - scrolling) + * vcons->state.screen.width) % size; + else + start = vis_start; + end = start + abs (scrolling) * vcons->state.screen.width - 1; + + cons_vcons_write (vcons, + vcons->state.screen.matrix + start, + end < size + ? end - start + 1 + : size - start, + 0, (scrolling > 0) + ? vcons->state.screen.height - scrolling : 0); + if (end >= size) + cons_vcons_write (vcons, + vcons->state.screen.matrix, + end - size + 1, + 0, (size - vis_start) + / vcons->state.screen.width); + } + + /* Set the new cursor position. */ + { + uint32_t row = vcons->state.cursor.row; + uint32_t height = vcons->state.screen.height; + + if (row + new_scr < height) + { + cons_vcons_set_cursor_pos (vcons, vcons->state.cursor.col, + row + new_scr); + if (row + vcons->scrolling >= height) + /* The cursor was invisible before. */ + cons_vcons_set_cursor_status (vcons, vcons->state.cursor.status); + } + else if (row + vcons->scrolling < height) + /* The cursor was visible before. */ + cons_vcons_set_cursor_status (vcons, CONS_CURSOR_INVISIBLE); + } + + cons_vcons_update (vcons); + vcons->scrolling -= scrolling; + mutex_unlock (&vcons->lock); + + return -scrolling; +} |