An initial stab at ALSA support.

It's very raw right now.

Makefile

@@ -1,15 +1,18 @@
 INSTALL = install
 
+CFLAGS ?= -DUSE_ALSA
 SRCS = \
 	cli.c \
+	alsa.c \
 	espeakup.c  \
+	espeak_sound.c \
 	queue.c \
 		softsynth.c \
 	synth.c
 
 OBJS = $(SRCS:.c=.o)
 
-LDLIBS = -lespeak -lpthread
+LDLIBS = -lespeak -lasound
 
 PREFIX = /usr
 MANDIR = $(PREFIX)/share/man/man8

alsa.c

@@ -0,0 +1,149 @@
+/*
+ *  espeakup - interface which allows speakup to use espeak
+ *
+ *  Copyright (C) 2008 William Hubbs
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *   This program is distributed in the hope that it will be useful,
+ *   but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *   GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+/*
+ * File: alsa.c
+ * Description: Produce audio by calling the ALSA library directly.
+*/
+
+#ifdef USE_ALSA
+#include <stdio.h>
+#include <stdlib.h>
+#include <limits.h>
+#define ALSA_PCM_NEW_HW_PARAMS_API
+#include <alsa/asoundlib.h>
+#include "espeakup.h"
+
+int minimum(int x, int y)
+{
+	if (x <= y)
+		return x;
+	else
+		return y;
+}
+
+static snd_pcm_t *handle;
+static snd_pcm_hw_params_t *params;
+snd_pcm_status_t *status;
+static unsigned int rate = 22050;	/* sample rate */
+static int dir = 0;
+static snd_pcm_uframes_t frames;
+
+static int alsa_play_callback(short *audio, int numsamples,
+							  espeak_EVENT * events)
+{
+	int samples_written = 0;
+	int avail;
+	int to_write;
+	snd_pcm_state_t state;
+	snd_pcm_status(handle, status);
+	state = snd_pcm_status_get_state(status);
+	if (state != SND_PCM_STATE_RUNNING)
+		snd_pcm_prepare(handle);
+
+	while (numsamples > 0) {
+		if (stopped) {
+			snd_pcm_drop(handle);
+			stopped = 0;
+			return 1;
+		}
+		avail = snd_pcm_avail_update(handle);
+		if (avail <= 0)
+			continue;
+		avail = minimum(avail, 32 * 2);
+		to_write = minimum(avail, numsamples);
+		samples_written = snd_pcm_writei(handle, audio, to_write);
+		if (samples_written == -EPIPE)
+			snd_pcm_prepare(handle);
+		else {
+			numsamples -= samples_written;
+			audio += samples_written;
+		}
+	}
+
+	return 0;
+}
+
+int init_audio(void)
+{
+	int rc;
+	unsigned saved_rate;
+
+	rate = 22050;
+
+	/* Open PCM device for playback. */
+	rc = snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0);
+	if (rc < 0) {
+		fprintf(stderr,
+				"unable to open pcm device: %s\n", snd_strerror(rc));
+		return rc;
+	}
+
+	/* Allocate a hardware parameters object. */
+	rc = snd_pcm_hw_params_malloc(&params);
+	if (rc < 0) {
+		fprintf(stderr,
+				"Unable to allocate memory to store audio parameters: %s\n",
+				snd_strerror(rc));
+		return rc;
+	}
+	rc = snd_pcm_status_malloc(&status);
+	if (rc < 0) {
+		fprintf(stderr,
+				"Unable to allocate memory to store PCM status: %s\n",
+				snd_strerror(rc));
+		return rc;
+	}
+
+
+	/* Fill it in with default values. */
+	snd_pcm_hw_params_any(handle, params);
+
+	/* Set the desired hardware parameters. */
+
+	/* Interleaved mode */
+	snd_pcm_hw_params_set_access(handle, params,
+								 SND_PCM_ACCESS_RW_INTERLEAVED);
+
+	/* Signed 16-bit little-endian format */
+	snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16_LE);
+
+	/* One channel  */
+	snd_pcm_hw_params_set_channels(handle, params, 1);
+
+	saved_rate = rate;
+	snd_pcm_hw_params_set_rate_near(handle, params, &rate, &dir);
+
+	/* Set period size to 32 frames. */
+	frames = 32;
+	snd_pcm_hw_params_set_period_size_near(handle, params, &frames, &dir);
+
+	/* Write the parameters to the driver */
+	rc = snd_pcm_hw_params(handle, params);
+	if (rc < 0) {
+		fprintf(stderr,
+				"unable to set hw parameters: %s\n", snd_strerror(rc));
+		return rc;
+	}
+
+	audio_mode = AUDIO_OUTPUT_RETRIEVAL;
+	audio_callback = alsa_play_callback;
+	return 0;
+}
+#endif

espeak_sound.c

@@ -0,0 +1,9 @@
+#ifndef USE_ALSA
+#include "espeakup.h"
+int init_audio(void)
+{
+	audio_mode = AUDIO_OUTPUT_PLAYBACK;
+	audio_callback = NULL;
+	return 0;
+}
+#endif

espeakup.c

@@ -42,6 +42,10 @@ const int defaultVolume = 5;
 char *defaultVoice = NULL;
 int debug = 0;
 
+volatile int stopped = 0;
+espeak_AUDIO_OUTPUT audio_mode;
+t_espeak_callback *audio_callback = NULL;
+
 int espeakup_is_running(void)
 {
 	int rc;
@@ -115,6 +119,10 @@ int main(int argc, char **argv)
 	signal(SIGINT, espeakup_sighandler);
 	signal(SIGTERM, espeakup_sighandler);
 
+	if (init_audio() < 0) {
+		return 5;
+	}
+
 	if (!debug) {
 		/* become a daemon */
 		daemon(0, 1);
@@ -127,7 +135,8 @@ int main(int argc, char **argv)
 	}
 
 	/* initialize espeak */
-	espeak_Initialize(AUDIO_OUTPUT_PLAYBACK, 0, NULL, 0);
+	espeak_Initialize(audio_mode, 0, NULL, 0);
+	espeak_SetSynthCallback(audio_callback);
 
 	/* Setup initial voice parameters */
 	if (defaultVoice) {

espeakup.h

@@ -78,5 +78,9 @@ extern int open_softsynth(void);
 extern void close_softsynth(void);
 extern void main_loop(struct synth_t *s);
 extern void * queue_runner(void *arg);
+extern int init_audio(void);
+extern volatile int stopped;
 
+extern espeak_AUDIO_OUTPUT audio_mode;
+extern t_espeak_callback *audio_callback;
 #endif

synth.c

@@ -114,6 +114,7 @@ espeak_ERROR set_volume(struct synth_t * s, int vol, enum adjust_t adj)
 
 espeak_ERROR stop_speech(void)
 {
+	stopped = 1;
 	return (espeak_Cancel());
 }
 
@@ -121,6 +122,7 @@ espeak_ERROR speak_text(struct synth_t * s)
 {
 	espeak_ERROR rc;
 
+	stopped = 0;
 	rc = espeak_Synth(s->buf, s->len + 1, 0, POS_CHARACTER, 0, 0, NULL,
 					  NULL);
 	return rc;