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vi: a few trivial optimizations to keyboard reading code; bump timeout to 50s.

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function                                             old     new   delta
edit_file                                            901     912     +11
count_lines                                           74      72      -2
readit                                               306     289     -17
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 11/-19)             Total: -8 bytes
This commit is contained in:
Denis Vlasenko 2008-10-16 09:46:07 +00:00
parent 7960ea8918
commit 8ef801b40c
1 changed files with 29 additions and 18 deletions
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47
editors/vi.c
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@ -629,12 +629,12 @@ static void edit_file(char *fn)
}
#endif
do_cmd(c); // execute the user command
//
// poll to see if there is input already waiting. if we are
// not able to display output fast enough to keep up, skip
// the display update until we catch up with input.
if (mysleep(0) == 0) {
// no input pending- so update output
if (!chars_to_parse && mysleep(0) == 0) {
// no input pending - so update output
refresh(FALSE);
show_status_line();
}
@ -2243,8 +2243,10 @@ static char readit(void) // read (maybe cursor) key from stdin
n = chars_to_parse;
if (n == 0) {
// If no data, block waiting for input.
n = safe_read(0, readbuffer, 1);
// If no data, block waiting for input
// (can't read more than minimal ESC sequence -
// see "n = 0" below).
n = safe_read(0, readbuffer, 3);
if (n <= 0) {
error:
go_bottom_and_clear_to_eol();
@ -2264,25 +2266,29 @@ static char readit(void) // read (maybe cursor) key from stdin
// If it's an escape sequence, loop through known matches.
if (c == 27) {
const struct esc_cmds *eindex;
struct pollfd pfd;
pfd.fd = STDIN_FILENO;
pfd.events = POLLIN;
for (eindex = esccmds; eindex < esccmds + ARRAY_SIZE(esccmds); eindex++) {
// n - position in seq to read
int i = 0; // position in seq to compare
int cnt = strnlen(eindex->seq, 4);
// n - position in sequence we did not read yet
int i = 0; // position in sequence to compare
// Loop through chars in this sequence.
// Loop through chars in this sequence
for (;;) {
// We've matched this escape sequence up to [i-1]
// So far escape sequence matches up to [i-1]
if (n <= i) {
// Need more chars, read another one if it wouldn't block.
// (Note that escape sequences come in as a unit,
// so if we would block it's not really an escape sequence.)
struct pollfd pfd;
pfd.fd = 0;
pfd.events = POLLIN;
// Timeout is needed to reconnect escape sequences split
// up by transmission over a serial console.
if (safe_poll(&pfd, 1, 25)) {
// Timeout is needed to reconnect escape sequences
// split up by transmission over a serial console.
// Even though inter-char delay on 1200 baud is <10ms,
// process scheduling can enlarge it arbitrarily,
// on both send and receive sides.
// Erring on the safe side - 5 timer ticks on 100 HZ.
if (safe_poll(&pfd, 1, 50)) {
if (safe_read(0, readbuffer + n, 1) <= 0)
goto error;
n++;
@ -2296,9 +2302,14 @@ static char readit(void) // read (maybe cursor) key from stdin
}
if (readbuffer[i] != eindex->seq[i])
break; // try next seq
if (++i == cnt) { // entire seq matched
i++;
if (i == 4 || !eindex->seq[i]) { // entire seq matched
c = eindex->val;
n = 0;
// n -= i; memmove(...);
// would be more correct,
// but we never read ahead that much,
// and n == i here.
goto loop_out;
}
}
@ -2306,7 +2317,7 @@ static char readit(void) // read (maybe cursor) key from stdin
// We did not find matching sequence, it was a bare ESC.
// We possibly read and stored more input in readbuffer by now.
}
loop_out:
loop_out:
chars_to_parse = n;
return c;