/**
* Stores the current cursor column in '*cols'.
* Returns 1 if OK, or 0 if failed to determine cursor pos.
*/
static int queryCursor(int fd, int* cols)
{
/* control sequence - report cursor location */
fd_printf(fd, "\x1b[6n");
/* Parse the response: ESC [ rows ; cols R */
if (fd_read_char(fd, 100) == 0x1b &&
fd_read_char(fd, 100) == '[') {
int n = 0;
while (1) {
int ch = fd_read_char(fd, 100);
if (ch == ';') {
/* Ignore rows */
n = 0;
}
else if (ch == 'R') {
/* Got cols */
if (n != 0 && n < 1000) {
*cols = n;
}
break;
}
else if (ch >= 0 && ch <= '9') {
n = n * 10 + ch - '0';
}
else {
break;
}
}
return 1;
}
return 0;
}
/**
* If escape (27) was received, reads subsequent
* chars to determine if this is a known special key.
*
* Returns SPECIAL_NONE if unrecognised, or -1 if EOF.
*
* If no additional char is received within a short time,
* 27 is returned.
*/
static int check_special(int fd)
{
int c = fd_read_char(fd, 50);
int c2;
if (c < 0) {
return 27;
}
c2 = fd_read_char(fd, 50);
if (c2 < 0) {
return c2;
}
if (c == '[' || c == 'O') {
/* Potential arrow key */
switch (c2) {
case 'A':
return SPECIAL_UP;
case 'B':
return SPECIAL_DOWN;
case 'C':
return SPECIAL_RIGHT;
case 'D':
return SPECIAL_LEFT;
case 'F':
return SPECIAL_END;
case 'H':
return SPECIAL_HOME;
}
}
if (c == '[' && c2 >= '1' && c2 <= '8') {
/* extended escape */
c = fd_read_char(fd, 50);
if (c == '~') {
switch (c2) {
case '2':
return SPECIAL_INSERT;
case '3':
return SPECIAL_DELETE;
case '5':
return SPECIAL_PAGE_UP;
case '6':
return SPECIAL_PAGE_DOWN;
case '7':
return SPECIAL_HOME;
case '8':
return SPECIAL_END;
}
}
while (c != -1 && c != '~') {
/* .e.g \e[12~ or '\e[11;2~ discard the complete sequence */
c = fd_read_char(fd, 50);
}
}
return SPECIAL_NONE;
}
static int getWindowSize(struct current *current)
{
struct winsize ws;
if (ioctl(STDOUT_FILENO, TIOCGWINSZ, &ws) == 0 && ws.ws_col != 0) {
current->cols = ws.ws_col;
return 0;
}
/* Failed to query the window size. Perhaps we are on a serial terminal.
* Try to query the width by sending the cursor as far to the right
* and reading back the cursor position.
* Note that this is only done once per call to linenoise rather than
* every time the line is refreshed for efficiency reasons.
*/
if (current->cols == 0) {
current->cols = 80;
/* Move cursor far right and report cursor position, then back to the left */
fd_printf(current->fd, "\x1b[999C" "\x1b[6n");
/* Parse the response: ESC [ rows ; cols R */
if (fd_read_char(current->fd, 100) == 0x1b && fd_read_char(current->fd, 100) == '[') {
int n = 0;
while (1) {
int ch = fd_read_char(current->fd, 100);
if (ch == ';') {
/* Ignore rows */
n = 0;
}
else if (ch == 'R') {
/* Got cols */
if (n != 0 && n < 1000) {
current->cols = n;
}
break;
}
else if (ch >= 0 && ch <= '9') {
n = n * 10 + ch - '0';
}
else {
break;
}
}
}
}
return 0;
}
/**
* Reads a complete utf-8 character
* and returns the unicode value, or -1 on error.
*/
static int fd_read(struct current *current)
{
#ifdef USE_UTF8
char buf[4];
int n;
int i;
int c;
if (read(current->fd, &buf[0], 1) != 1) {
return -1;
}
n = utf8_charlen(buf[0]);
if (n < 1 || n > 3) {
return -1;
}
for (i = 1; i < n; i++) {
if (read(current->fd, &buf[i], 1) != 1) {
return -1;
}
}
buf[n] = 0;
/* decode and return the character */
utf8_tounicode(buf, &c);
return c;
#else
return fd_read_char(current->fd, -1);
#endif
}