1#include <linux/console.h>
2#include <linux/types.h>
3#include <linux/wait.h>
4
5#include "speakup.h"
6#include "spk_priv.h"
7
8#define synthBufferSize 8192	/* currently 8K bytes */
9
10static u_char synth_buffer[synthBufferSize];	/* guess what this is for! */
11static u_char *buff_in = synth_buffer;
12static u_char *buff_out = synth_buffer;
13static u_char *buffer_end = synth_buffer+synthBufferSize-1;
14
15/* These try to throttle applications by stopping the TTYs
16 * Note: we need to make sure that we will restart them eventually, which is
17 * usually not possible to do from the notifiers. TODO: it should be possible
18 * starting from linux 2.6.26.
19 *
20 * So we only stop when we know alive == 1 (else we discard the data anyway),
21 * and the alive synth will eventually call start_ttys from the thread context.
22 */
23void speakup_start_ttys(void)
24{
25	int i;
26
27	for (i = 0; i < MAX_NR_CONSOLES; i++) {
28		if (speakup_console[i] && speakup_console[i]->tty_stopped)
29			continue;
30		if ((vc_cons[i].d != NULL) && (vc_cons[i].d->port.tty != NULL))
31			start_tty(vc_cons[i].d->port.tty);
32	}
33}
34EXPORT_SYMBOL_GPL(speakup_start_ttys);
35
36static void speakup_stop_ttys(void)
37{
38	int i;
39
40	for (i = 0; i < MAX_NR_CONSOLES; i++)
41		if ((vc_cons[i].d != NULL) && (vc_cons[i].d->port.tty != NULL))
42			stop_tty(vc_cons[i].d->port.tty);
43}
44
45static int synth_buffer_free(void)
46{
47	int bytesFree;
48
49	if (buff_in >= buff_out)
50		bytesFree = synthBufferSize - (buff_in - buff_out);
51	else
52		bytesFree = buff_out - buff_in;
53	return bytesFree;
54}
55
56int synth_buffer_empty(void)
57{
58	return (buff_in == buff_out);
59}
60EXPORT_SYMBOL_GPL(synth_buffer_empty);
61
62void synth_buffer_add(char ch)
63{
64	if (!synth->alive) {
65		/* This makes sure that we won't stop TTYs if there is no synth
66		 * to restart them */
67		return;
68	}
69	if (synth_buffer_free() <= 100) {
70		synth_start();
71		speakup_stop_ttys();
72	}
73	if (synth_buffer_free() <= 1)
74		return;
75	*buff_in++ = ch;
76	if (buff_in > buffer_end)
77		buff_in = synth_buffer;
78}
79
80char synth_buffer_getc(void)
81{
82	char ch;
83
84	if (buff_out == buff_in)
85		return 0;
86	ch = *buff_out++;
87	if (buff_out > buffer_end)
88		buff_out = synth_buffer;
89	return ch;
90}
91EXPORT_SYMBOL_GPL(synth_buffer_getc);
92
93char synth_buffer_peek(void)
94{
95	if (buff_out == buff_in)
96		return 0;
97	return *buff_out;
98}
99EXPORT_SYMBOL_GPL(synth_buffer_peek);
100
101void synth_buffer_clear(void)
102{
103	buff_in = buff_out = synth_buffer;
104	return;
105}
106EXPORT_SYMBOL_GPL(synth_buffer_clear);
107