diff options
| -rw-r--r-- | lib/mp-readline/readline.c | 39 |
1 files changed, 24 insertions, 15 deletions
diff --git a/lib/mp-readline/readline.c b/lib/mp-readline/readline.c index ae61f3f807..767d509c7e 100644 --- a/lib/mp-readline/readline.c +++ b/lib/mp-readline/readline.c @@ -57,6 +57,25 @@ STATIC char *str_dup_maybe(const char *str) { return s2; } +STATIC void move_cursor_back(uint pos) { + if (pos <= 4) { + // fast path for most common case of 1 step back + stdout_tx_strn("\b\b\b\b", pos); + } else { + char vt100_command[6]; + // snprintf needs space for the terminating null character + int n = snprintf(&vt100_command[0], sizeof(vt100_command), "\x1b[%u", pos); + if (n > 0) { + vt100_command[n] = 'D'; // replace null char + stdout_tx_strn(vt100_command, n + 1); + } + } +} + +STATIC void erase_line_from_cursor(void) { + stdout_tx_strn("\x1b[K", 3); +} + typedef struct _readline_t { vstr_t *line; int orig_line_len; @@ -66,7 +85,7 @@ typedef struct _readline_t { char escape_seq_buf[1]; } readline_t; -readline_t rl; +STATIC readline_t rl; int readline_process_char(int c) { int last_line_len = rl.line->len; @@ -215,30 +234,20 @@ end_key: } // redraw command prompt, efficiently - // TODO we can probably use some more sophisticated VT100 commands here if (redraw_step_back > 0) { - for (int i = 0; i < redraw_step_back; i++) { - stdout_tx_str("\b"); - } + move_cursor_back(redraw_step_back); rl.cursor_pos -= redraw_step_back; } if (redraw_from_cursor) { if (rl.line->len < last_line_len) { // erase old chars - for (int i = rl.cursor_pos; i < last_line_len; i++) { - stdout_tx_str(" "); - } - // step back - for (int i = rl.cursor_pos; i < last_line_len; i++) { - stdout_tx_str("\b"); - } + // (number of chars to erase: last_line_len - rl.cursor_pos) + erase_line_from_cursor(); } // draw new chars stdout_tx_strn(rl.line->buf + rl.cursor_pos, rl.line->len - rl.cursor_pos); // move cursor forward if needed (already moved forward by length of line, so move it back) - for (int i = rl.cursor_pos + redraw_step_forward; i < rl.line->len; i++) { - stdout_tx_str("\b"); - } + move_cursor_back(rl.line->len - (rl.cursor_pos + redraw_step_forward)); rl.cursor_pos += redraw_step_forward; } else if (redraw_step_forward > 0) { // draw over old chars to move cursor forwards |