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console: add basic cursor movements

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Add functions to move the cursor up/down/left/right. We must take care
of integer overflows here as the application may send us arbitrarily big
numbers.

Signed-off-by: David Herrmann <dh.herrmann@googlemail.com>
This commit is contained in:
David Herrmann 2012-02-04 15:50:03 +01:00
parent 466fcc3b06
commit d8ff83c5cb
2 changed files with 101 additions and 0 deletions
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95
src/console.c
View File

@ -306,3 +306,98 @@ void kmscon_console_move_to(struct kmscon_console *con, unsigned int x,
con->cursor_y = con->cells_y - 1;
}
}
void kmscon_console_move_up(struct kmscon_console *con, unsigned int num,
bool scroll)
{
unsigned int diff;
if (!con || !num)
return;
if (num > con->cells_y)
num = con->cells_y;
if (con->rel_addr) {
diff = con->cursor_y - con->margin_top;
if (num > diff) {
num -= diff;
if (scroll)
kmscon_buffer_scroll_down(con->cells, num);
con->cursor_y = con->margin_top;
} else {
con->cursor_y -= num;
}
} else {
if (num > con->cursor_y) {
num -= con->cursor_y;
if (scroll)
kmscon_buffer_scroll_down(con->cells, num);
con->cursor_y = 0;
} else {
con->cursor_y -= num;
}
}
}
void kmscon_console_move_down(struct kmscon_console *con, unsigned int num,
bool scroll)
{
unsigned int diff;
if (!con || !num)
return;
if (num > con->cells_y)
num = con->cells_y;
if (con->rel_addr) {
diff = con->margin_bottom - con->cursor_y;
if (num > diff) {
num -= diff;
if (scroll)
kmscon_buffer_scroll_up(con->cells, num);
con->cursor_y = con->margin_bottom;
} else {
con->cursor_y += num;
}
} else {
diff = con->cells_y - con->cursor_y - 1;
if (num > diff) {
num -= diff;
if (scroll)
kmscon_buffer_scroll_up(con->cells, num);
con->cursor_y = con->cells_y - 1;
} else {
con->cursor_y += num;
}
}
}
void kmscon_console_move_left(struct kmscon_console *con, unsigned int num)
{
if (!con || !num)
return;
if (num > con->cells_x)
num = con->cells_x;
if (num > con->cursor_x)
con->cursor_x = 0;
else
con->cursor_x -= num;
}
void kmscon_console_move_right(struct kmscon_console *con, unsigned int num)
{
if (!con || !num)
return;
if (num > con->cells_x)
num = con->cells_x;
if (num + con->cursor_x >= con->cells_x)
con->cursor_x = con->cells_x - 1;
else
con->cursor_x += num;
}

6
src/console.h
View File

@ -91,5 +91,11 @@ void kmscon_console_write(struct kmscon_console *con, kmscon_symbol_t ch);
void kmscon_console_newline(struct kmscon_console *con);
void kmscon_console_move_to(struct kmscon_console *con, unsigned int x,
unsigned int y);
void kmscon_console_move_up(struct kmscon_console *con, unsigned int num,
bool scroll);
void kmscon_console_move_down(struct kmscon_console *con, unsigned int num,
bool scroll);
void kmscon_console_move_left(struct kmscon_console *con, unsigned int num);
void kmscon_console_move_right(struct kmscon_console *con, unsigned int num);
#endif /* KMSCON_CONSOLE_H */