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authorDenys Vlasenko <vda.linux@googlemail.com>2010-05-16 22:45:44 (GMT)
committer Denys Vlasenko <vda.linux@googlemail.com>2010-05-16 22:45:44 (GMT)
commit248c324f7c6d407467ab3ad9057dfe33fb2723d8 (patch)
tree2f9831a30685bfdee75872bf58639a527144eec2
parentd9a3e89f501800c3e7c779b7e9545a5c80134593 (diff)
downloadbusybox-248c324f7c6d407467ab3ad9057dfe33fb2723d8.tar.gz
busybox-248c324f7c6d407467ab3ad9057dfe33fb2723d8.tar.bz2
lineedit: fix moving backwards across lines with wide chars
function old new delta input_backward 212 208 -4 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
-rw-r--r--libbb/lineedit.c67
1 files changed, 46 insertions, 21 deletions
diff --git a/libbb/lineedit.c b/libbb/lineedit.c
index bc089ab..836fc00 100644
--- a/libbb/lineedit.c
+++ b/libbb/lineedit.c
@@ -413,12 +413,22 @@ static void beep(void)
bb_putchar('\007');
}
+static void put_prompt(void)
+{
+ unsigned w;
+
+ out1str(cmdedit_prompt);
+ fflush_all();
+ cursor = 0;
+ w = cmdedit_termw; /* read volatile var once */
+ cmdedit_y = cmdedit_prmt_len / w; /* new quasireal y */
+ cmdedit_x = cmdedit_prmt_len % w;
+}
+
/* Move back one character */
/* (optimized for slow terminals) */
static void input_backward(unsigned num)
{
- int count_y;
-
if (num > cursor)
num = cursor;
if (num == 0)
@@ -456,29 +466,44 @@ static void input_backward(unsigned num)
}
/* Need to go one or more lines up */
-//FIXME: this does not work correctly if prev line has one "unfilled" screen position
-//caused by wide unicode char not fitting in that one screen position.
- num -= cmdedit_x;
- {
- unsigned w = cmdedit_termw; /* volatile var */
+ if (ENABLE_UNICODE_WIDE_WCHARS) {
+ /* With wide chars, it is hard to "backtrack"
+ * and reliably figure out where to put cursor.
+ * Example (<> is a wide char; # is an ordinary char, _ cursor):
+ * |prompt: <><> |
+ * |<><><><><><> |
+ * |_ |
+ * and user presses left arrow. num = 1, cmdedit_x = 0,
+ * We need to go up one line, and then - how do we know that
+ * we need to go *10* positions to the right? Because
+ * |prompt: <>#<>|
+ * |<><><>#<><><>|
+ * |_ |
+ * in this situation we need to go *11* positions to the right.
+ *
+ * A simpler thing to do is to redraw everything from the start
+ * up to new cursor position (which is already known):
+ */
+ unsigned sv_cursor;
+ if (cmdedit_y > 0) /* up to start y */
+ printf("\033[%uA", cmdedit_y);
+ bb_putchar('\r');
+ cmdedit_y = 0;
+ sv_cursor = cursor;
+ put_prompt(); /* sets cursor to 0 */
+ while (cursor < sv_cursor)
+ put_cur_glyph_and_inc_cursor();
+ } else {
+ int count_y;
+ unsigned w;
+ num -= cmdedit_x;
+ w = cmdedit_termw; /* read volatile var once */
count_y = 1 + (num / w);
cmdedit_y -= count_y;
cmdedit_x = w * count_y - num;
+ /* go to 1st column; go up; go to correct column */
+ printf("\r" "\033[%uA" "\033[%uC", count_y, cmdedit_x);
}
- /* go to 1st column; go up; go to correct column */
- printf("\r" "\033[%uA" "\033[%uC", count_y, cmdedit_x);
-}
-
-static void put_prompt(void)
-{
- unsigned w;
-
- out1str(cmdedit_prompt);
- fflush_all();
- cursor = 0;
- w = cmdedit_termw; /* read volatile var once */
- cmdedit_y = cmdedit_prmt_len / w; /* new quasireal y */
- cmdedit_x = cmdedit_prmt_len % w;
}
/* draw prompt, editor line, and clear tail */