248c324f7
Denys Vlasenko
2010-05-17
Subject
lineedit: fix moving backwards across lines with wide chars
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libbb/lineedit.c+46 -21
| @@ -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 */ | |