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);