1 /* interestingtimes.c - cursor control
2 *
3 * Copyright 2015 Rob Landley <rob@landley.net>
4 */
5
6 #include "toys.h"
7
xgettty(void)8 int xgettty(void)
9 {
10 int i, j;
11
12 for (i = 0; i<3; i++) if (isatty(j = (i+1)%3)) return j;
13
14 return xopen("/dev/tty", O_RDWR);
15 }
16
17 // Quick and dirty query size of terminal, doesn't do ANSI probe fallback.
18 // set x=80 y=25 before calling to provide defaults. Returns 0 if couldn't
19 // determine size.
20
terminal_size(unsigned * xx,unsigned * yy)21 int terminal_size(unsigned *xx, unsigned *yy)
22 {
23 struct winsize ws;
24 unsigned i, x = 0, y = 0;
25 char *s;
26
27 // stdin, stdout, stderr
28 for (i=0; i<3; i++) {
29 memset(&ws, 0, sizeof(ws));
30 if (!ioctl(i, TIOCGWINSZ, &ws)) {
31 if (ws.ws_col) x = ws.ws_col;
32 if (ws.ws_row) y = ws.ws_row;
33
34 break;
35 }
36 }
37 s = getenv("COLUMNS");
38 if (s) sscanf(s, "%u", &x);
39 s = getenv("LINES");
40 if (s) sscanf(s, "%u", &y);
41
42 // Never return 0 for either value, leave it at default instead.
43 if (xx && x) *xx = x;
44 if (yy && y) *yy = y;
45
46 return x || y;
47 }
48
49 // Reset terminal to known state, saving copy of old state if old != NULL.
set_terminal(int fd,int raw,struct termios * old)50 int set_terminal(int fd, int raw, struct termios *old)
51 {
52 struct termios termio;
53
54 // Fetch local copy of old terminfo, and copy struct contents to *old if set
55 if (!tcgetattr(fd, &termio) && old) *old = termio;
56
57 // the following are the bits set for an xterm. Linux text mode TTYs by
58 // default add two additional bits that only matter for serial processing
59 // (turn serial line break into an interrupt, and XON/XOFF flow control)
60
61 // Any key unblocks output, swap CR and NL on input
62 termio.c_iflag = IXANY|ICRNL|INLCR;
63 if (toys.which->flags & TOYFLAG_LOCALE) termio.c_iflag |= IUTF8;
64
65 // Output appends CR to NL, does magic undocumented postprocessing
66 termio.c_oflag = ONLCR|OPOST;
67
68 // Leave serial port speed alone
69 // termio.c_cflag = C_READ|CS8|EXTB;
70
71 // Generate signals, input entire line at once, echo output
72 // erase, line kill, escape control characters with ^
73 // erase line char at a time
74 // "extended" behavior: ctrl-V quotes next char, ctrl-R reprints unread chars,
75 // ctrl-W erases word
76 termio.c_lflag = ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
77
78 if (raw) cfmakeraw(&termio);
79
80 return tcsetattr(fd, TCSANOW, &termio);
81 }
82
83 // Scan stdin for a keypress, parsing known escape sequences
84 // seqs is array of char * strings, ends with NULL ptr
85 // Returns: 0-255=literal, -1=EOF, -2=NONE, 256-...=index into seq
86 // scratch space is necessary because last char of !seq could start new seq
87 // Zero out first byte of scratch before first call to scan_key
88 // block=0 allows fetching multiple characters before updating display
scan_key(char * scratch,char ** seqs,int block)89 int scan_key(char *scratch, char **seqs, int block)
90 {
91 struct pollfd pfd;
92 int maybe, i, j;
93 char *test;
94
95 for (;;) {
96 pfd.fd = 0;
97 pfd.events = POLLIN;
98 pfd.revents = 0;
99
100 // check sequences
101 maybe = 0;
102 if (*scratch) {
103 for (i = maybe = 0; (test = seqs[i]); i++) {
104 for (j = 0; j<*scratch; j++) if (scratch[j+1] != test[j]) break;
105 if (j == *scratch) {
106 maybe = 1;
107 if (!test[j]) {
108 // We recognized current sequence: consume and return
109 *scratch = 0;
110 return 256+i;
111 }
112 }
113 }
114 // If current data can't be a known sequence, return next raw char
115 if (!maybe) break;
116 }
117
118 // Need more data to decide
119
120 // 30 miliseconds is about the gap between characters at 300 baud
121 if (maybe || !block) if (!xpoll(&pfd, 1, 30*maybe)) break;
122
123 if (1 != read(0, scratch+1+*scratch, 1)) return -1;
124 ++*scratch;
125 }
126
127 // Was not a sequence
128 if (!*scratch) return -2;
129 i = scratch[1];
130 if (--*scratch) memmove(scratch+1, scratch+2, *scratch);
131
132 return i;
133 }
134