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libbb: add forgotten file from previous commit :(

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This commit is contained in:
Denis Vlasenko
2008-10-25 23:23:32 +00:00
parent 0112ff5203
commit 39b0135c59
1 changed files with 146 additions and 0 deletions
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146
libbb/read_key.c Normal file
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@@ -0,0 +1,146 @@
/* vi: set sw=4 ts=4: */
/*
* Utility routines.
*
* Copyright (C) 2008 Denys Vlasenko
*
* Licensed under GPL version 2, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
int FAST_FUNC read_key(int fd, smalluint *nbuffered, char *buffer)
{
struct pollfd pfd;
const char *seq;
int n;
int c;
/* Known escape sequences for cursor and function keys */
static const char esccmds[] ALIGN1 = {
'O','A' |0x80,KEYCODE_UP ,
'O','B' |0x80,KEYCODE_DOWN ,
'O','C' |0x80,KEYCODE_RIGHT ,
'O','D' |0x80,KEYCODE_LEFT ,
'O','H' |0x80,KEYCODE_HOME ,
'O','F' |0x80,KEYCODE_END ,
#if 0
'O','P' |0x80,KEYCODE_FUN1 ,
'O','Q' |0x80,KEYCODE_FUN2 ,
'O','R' |0x80,KEYCODE_FUN3 ,
'O','S' |0x80,KEYCODE_FUN4 ,
#endif
'[','A' |0x80,KEYCODE_UP ,
'[','B' |0x80,KEYCODE_DOWN ,
'[','C' |0x80,KEYCODE_RIGHT ,
'[','D' |0x80,KEYCODE_LEFT ,
'[','H' |0x80,KEYCODE_HOME ,
'[','F' |0x80,KEYCODE_END ,
'[','1','~' |0x80,KEYCODE_HOME ,
'[','2','~' |0x80,KEYCODE_INSERT ,
'[','3','~' |0x80,KEYCODE_DELETE ,
'[','4','~' |0x80,KEYCODE_END ,
'[','5','~' |0x80,KEYCODE_PAGEUP ,
'[','6','~' |0x80,KEYCODE_PAGEDOWN,
#if 0
'[','1','1','~'|0x80,KEYCODE_FUN1 ,
'[','1','2','~'|0x80,KEYCODE_FUN2 ,
'[','1','3','~'|0x80,KEYCODE_FUN3 ,
'[','1','4','~'|0x80,KEYCODE_FUN4 ,
'[','1','5','~'|0x80,KEYCODE_FUN5 ,
'[','1','7','~'|0x80,KEYCODE_FUN6 ,
'[','1','8','~'|0x80,KEYCODE_FUN7 ,
'[','1','9','~'|0x80,KEYCODE_FUN8 ,
'[','2','0','~'|0x80,KEYCODE_FUN9 ,
'[','2','1','~'|0x80,KEYCODE_FUN10 ,
'[','2','3','~'|0x80,KEYCODE_FUN11 ,
'[','2','4','~'|0x80,KEYCODE_FUN12 ,
#endif
0
};
n = *nbuffered;
if (n == 0) {
/* If no data, block waiting for input. If we read more
* than the minimal ESC sequence size, the "n=0" below
* would instead have to figure out how much to keep,
* resulting in larger code. */
n = safe_read(fd, buffer, 3);
if (n <= 0)
return -1;
}
/* Grab character to return from buffer */
c = (unsigned char)buffer[0];
n--;
if (n)
memmove(buffer, buffer + 1, n);
/* Only ESC starts ESC sequences */
if (c != 27)
goto ret;
/* Loop through known ESC sequences */
pfd.fd = fd;
pfd.events = POLLIN;
seq = esccmds;
while (*seq != '\0') {
/* n - position in sequence we did not read yet */
int i = 0; /* position in sequence to compare */
/* Loop through chars in this sequence */
while (1) {
/* So far escape sequence matched 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 block for long it's not really an escape sequence.
* Timeout is needed to reconnect escape sequences
* split up by transmission over a serial console. */
if (safe_poll(&pfd, 1, 50) == 0) {
/* No more data!
* Array is sorted from shortest to longest,
* we can't match anything later in array,
* break out of both loops. */
goto ret;
}
errno = 0;
if (safe_read(fd, buffer + n, 1) <= 0) {
/* If EAGAIN, then fd is O_NONBLOCK and poll lied:
* in fact, there is no data. */
if (errno != EAGAIN)
c = -1; /* otherwise it's EOF/error */
goto ret;
}
n++;
}
if (buffer[i] != (seq[i] & 0x7f)) {
/* This seq doesn't match, go to next */
seq += i;
/* Forward to last char */
while (!(*seq & 0x80))
seq++;
/* Skip it and the keycode which follows */
seq += 2;
break;
}
if (seq[i] & 0x80) {
/* Entire seq matched */
c = (signed char)seq[i+1];
n = 0;
/* n -= i; memmove(...);
* would be more correct,
* but we never read ahead that much,
* and n == i here. */
goto ret;
}
i++;
}
}
/* We did not find matching sequence, it was a bare ESC.
* We possibly read and stored more input in buffer[]
* by now. */
ret:
*nbuffered = n;
return c;
}