Use round-robin queue to synch; process text by chunks

8 files changed, 579 insertions, 145 deletions

diff --git a/src/Makefile.am b/src/Makefile.am
index 45e3704..b6c9ff9 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -1,6 +1,6 @@
 plugin_LTLIBRARIES = libgstespeak.la
 
-libgstespeak_la_SOURCES = gstespeak.c espeak.c
+libgstespeak_la_SOURCES = spin.c espeak.c gstespeak.c
 
 libgstespeak_la_CFLAGS = $(GST_CFLAGS) $(GIO_CFLAGS) $(GST_AUDIO_CFLAGS)
 libgstespeak_la_LIBADD = $(GST_LIBS) $(GIO_LIBS) $(GST_AUDIO_LIBS)
diff --git a/src/espeak.c b/src/espeak.c
index 265a243..f49cd6d 100644
--- a/src/espeak.c
+++ b/src/espeak.c
@@ -21,67 +21,99 @@
 #include <glib.h>
 #include <gio/gio.h>
 #include <espeak/speak_lib.h>
+#include <gst/gst.h>
 
-struct Espeak
+#include "spin.h"
+#include "espeak.h"
+
+struct _Espeak
 {
-    GOutputStream *buffer;
+    Econtext *context;
+    guint rate;
+    guint pitch;
+    const gchar *voice;
 };
 
-pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;
-static GOutputStream *buffer = NULL;
-static gint sample_rate = 0;
-static const espeak_VOICE **voices = NULL;
+static gint espeak_sample_rate = 0;
+static const espeak_VOICE **espeak_voices = NULL;
+static GOutputStream *espeak_buffer = NULL;
 
 static gint
-read_cb(short * data, int numsamples, espeak_EVENT * events)
+synth_cb(short * data, int numsamples, espeak_EVENT * events)
 {
     if (data == NULL)
         return 0;
 
     if (numsamples > 0)
-        g_output_stream_write(buffer, data, numsamples*2, NULL, NULL);
+        g_output_stream_write(espeak_buffer, data, numsamples*2, NULL, NULL);
+
+    GST_DEBUG("numsamples=%d data_size=%ld", numsamples*2,
+            g_memory_output_stream_get_data_size(G_MEMORY_OUTPUT_STREAM(
+                    espeak_buffer)));
 
     return 0;
 }
 
 static void
+synth(const gchar *text, GMemoryOutputStream *sound, gpointer self_)
+{
+    Espeak *self = (Espeak*)self_;
+
+    espeak_SetParameter(espeakPITCH, self->pitch, 0);
+    espeak_SetParameter(espeakRATE, self->rate, 0);
+    espeak_SetVoiceByName(self->voice);
+    espeak_buffer = G_OUTPUT_STREAM(sound);
+
+    espeak_Synth(text, strlen(text)+1, 0, POS_WORD, 0, espeakCHARS_UTF8,
+            NULL, NULL);
+}
+
+static void
 init()
 {
     static volatile gsize initialized = 0;
 
-    pthread_mutex_lock(&mutex);
     if (initialized == 0)
     {
         ++initialized;
-        sample_rate = espeak_Initialize(AUDIO_OUTPUT_SYNCHRONOUS, 4096, NULL, 0);
-        espeak_SetSynthCallback(read_cb);
-        voices = espeak_ListVoices(NULL);
+        espeak_sample_rate = espeak_Initialize(AUDIO_OUTPUT_SYNCHRONOUS, 4096,
+                NULL, 0);
+        espeak_SetSynthCallback(synth_cb);
+        espeak_voices = espeak_ListVoices(NULL);
+        spin_init(synth);
     }
-    pthread_mutex_unlock(&mutex);
 }
 
-struct Espeak*
+Espeak*
 espeak_new()
 {
     init();
 
-    if (sample_rate == EE_INTERNAL_ERROR)
-        return NULL;
+    Espeak *self = g_new0(Espeak, 1);
+    self->context = spin_new(self);
+    self->pitch = ESPEAK_DEFAULT_PITCH;
+    self->rate = ESPEAK_DEFAULT_RATE;
+    self->voice = ESPEAK_DEFAULT_VOICE;
 
-    struct Espeak *es = g_new(struct Espeak, 1);
-    es->buffer = g_memory_output_stream_new(NULL, 0, realloc, free);
+    return self;
+}
 
-    return es;
+void
+espeak_unref(Espeak *self)
+{
+    spin_unref(self->context);
+    memset(self, 0, sizeof(Espeak));
+    g_free(self);
 }
 
 gint
-espeak_sample_rate()
+espeak_get_sample_rate()
 {
-    return sample_rate;
+    return espeak_sample_rate;
 }
 
 gchar**
-espeak_voices()
+espeak_get_voices()
 {
     gsize count = 0;
     const espeak_VOICE **i;
@@ -89,52 +121,40 @@ espeak_voices()
 
     init();
 
-    for (i = voices; *i; ++i) ++count;
+    for (i = espeak_voices; *i; ++i) ++count;
     out = j = g_new0(gchar*, count); 
-    for (i = voices; *i; ++i)
+    for (i = espeak_voices; *i; ++i)
         *j++ = g_strconcat((*i)->name, ":", (*i)->languages+1, NULL);
 
     return out;
 }
 
-gboolean
-espeak_say(struct Espeak *es, const gchar *text, const gchar *voice,
-        guint pitch, guint rate)
+void
+espeak_set_pitch(Espeak *self, guint value)
 {
-    g_seekable_seek(G_SEEKABLE(es->buffer), 0, G_SEEK_SET, NULL, NULL);
-
-    pthread_mutex_lock(&mutex);
-    buffer = es->buffer;
-    espeak_SetParameter(espeakPITCH, pitch, 0);
-    espeak_SetParameter(espeakRATE, rate, 0);
-    espeak_SetVoiceByName(voice);
-    gint status = espeak_Synth(text, strlen(text)+1, 0, POS_WORD, 0,
-                espeakCHARS_AUTO, NULL, NULL);
-    buffer = NULL;
-    pthread_mutex_unlock(&mutex);
-
-    if (status != EE_OK)
-        return FALSE;
-
-    return TRUE;
+    self->pitch = value;
 }
 
-gpointer
-espeak_hear(struct Espeak *es, goffset offset, guint *size)
+void
+espeak_set_rate(Espeak *self, guint value)
 {
-    GMemoryOutputStream *mb = (GMemoryOutputStream*)es->buffer;
-
-    gpointer out = g_memory_output_stream_get_data(mb) + offset;
-    *size = MIN(g_memory_output_stream_get_data_size(mb) - offset, *size);
+    self->rate = value;
+}
 
-    return out;
+void
+espeak_set_voice(Espeak *self, const gchar *value)
+{
+    self->voice = value;
 }
 
 void
-espeak_unref(struct Espeak *es)
+espeak_say(Espeak *self, const gchar *text)
+{
+    spin_in(self->context, text);
+}
+
+gpointer
+espeak_hear(Espeak *self, gsize size)
 {
-    g_output_stream_close(es->buffer, NULL, NULL);
-    g_object_unref(es->buffer);
-    es->buffer = 0;
-    g_free(es);
+    return spin_out(self->context, &size);
 }
diff --git a/src/espeak.h b/src/espeak.h
index 6258ebd..b0e3f65 100644
--- a/src/espeak.h
+++ b/src/espeak.h
@@ -15,17 +15,24 @@
  * Boston, MA 02111-1307, USA.
  */
 
-#ifndef __ESPEAK_H__
-#define __ESPEAK_H__
+#ifndef ESPEAK_H
+#define ESPEAK_H
 
-struct Espeak;
+#define ESPEAK_DEFAULT_PITCH  50
+#define ESPEAK_DEFAULT_RATE   170 
+#define ESPEAK_DEFAULT_VOICE  "default"
 
-struct Espeak* espeak_new();
-gint espeak_sample_rate();
-gchar** espeak_voices();
-gboolean espeak_say(struct Espeak*, const gchar *text, const gchar *voice,
-        guint pitch, guint rate);
-gpointer espeak_hear(struct Espeak*, goffset offset, guint *size);
-void espeak_unref(struct Espeak*);
+struct _Espeak;
+typedef struct _Espeak Espeak;
+
+struct _Espeak* espeak_new();
+void            espeak_unref(struct _Espeak*);
+gint            espeak_get_sample_rate();
+gchar**         espeak_get_voices();
+void            espeak_set_pitch(struct _Espeak*, guint);
+void            espeak_set_rate(struct _Espeak*, guint);
+void            espeak_set_voice(struct _Espeak*, const gchar*);
+void            espeak_say(struct _Espeak*, const gchar *text);
+gpointer        espeak_hear(struct _Espeak*, gsize);
 
 #endif
diff --git a/src/gstespeak.c b/src/gstespeak.c
index 8fd36eb..8f5d8e5 100644
--- a/src/gstespeak.c
+++ b/src/gstespeak.c
@@ -112,7 +112,7 @@ gst_espeak_class_init (GstEspeakClass * klass)
     g_object_class_install_property(gobject_class, PROP_TEXT,
             g_param_spec_string("text", "Text",
                 "Text to pronounce", NULL,
-                G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+                G_PARAM_WRITABLE | G_PARAM_STATIC_STRINGS));
     g_object_class_install_property(gobject_class, PROP_PITCH,
             g_param_spec_uint("pitch", "Pitch adjustment",
                 "Pitch adjustment", 0, 99, 50,
@@ -144,16 +144,14 @@ static void
 gst_espeak_init (GstEspeak * self,
     GstEspeakClass * gclass)
 {
-    self->text = NULL;
-    self->uri = NULL;
-    self->pitch = 50;
-    self->rate = 170;
+    self->pitch = ESPEAK_DEFAULT_PITCH;
+    self->rate = ESPEAK_DEFAULT_RATE;
+    self->voice = g_strdup(ESPEAK_DEFAULT_VOICE);
+    self->voices = espeak_get_voices();
     self->speak = espeak_new();
-    self->voice = g_strdup("default");
-    self->voices = espeak_voices();
 
     self->caps = gst_caps_new_simple("audio/x-raw-int",
-            "rate", G_TYPE_INT, espeak_sample_rate(),
+            "rate", G_TYPE_INT, espeak_get_sample_rate(),
             "channels", G_TYPE_INT, 1,
             "endianness", G_TYPE_INT, G_BYTE_ORDER,
             "width", G_TYPE_INT, 16,
@@ -169,8 +167,6 @@ gst_espeak_finalize(GObject * self_)
 
     gst_caps_unref(self->caps); self->caps = NULL;
     espeak_unref(self->speak);  self->speak = NULL;
-    g_free(self->text);         self->text = NULL;
-    g_free(self->uri);          self->uri = NULL;
     g_free(self->voice);        self->voice = NULL;
     g_strfreev(self->voices);   self->voices = NULL;
 
@@ -179,57 +175,27 @@ gst_espeak_finalize(GObject * self_)
 
 /******************************************************************************/
 
-static gboolean
-gst_espeak_set_text(GstEspeak *self, const gchar *text)
-{
-    GstState state;
-
-    /* the element must be stopped in order to do this */
-    GST_OBJECT_LOCK(self);
-    state = GST_STATE(self);
-    GST_OBJECT_UNLOCK (self);
-
-    if (state != GST_STATE_READY && state != GST_STATE_NULL)
-    {
-        GST_DEBUG_OBJECT(self, "setting text in wrong state");
-        return FALSE;
-    }
-
-    g_free(self->text);
-    g_free(self->uri);
-
-    if (text == NULL) {
-        self->text = NULL;
-        self->uri = NULL;
-    } else {
-        self->text = g_strdup(text);
-        self->uri = gst_uri_construct ("espeak", self->text);
-    }
-
-    g_object_notify(G_OBJECT (self), "text");
-    gst_uri_handler_new_uri(GST_URI_HANDLER(self), self->uri);
-
-    return TRUE;
-}
-
 static void
-gst_espeak_set_property (GObject *object, guint prop_id,
+gst_espeak_set_property(GObject *object, guint prop_id,
     const GValue * value, GParamSpec * pspec)
 {
     GstEspeak *self = GST_ESPEAK(object);
 
     switch (prop_id) {
         case PROP_TEXT:
-            gst_espeak_set_text(self, g_value_get_string(value));
+            espeak_say(self->speak, g_value_get_string(value));
             break;
         case PROP_PITCH:
             self->pitch = g_value_get_uint(value);
+            espeak_set_pitch(self->speak, self->pitch);
             break;
         case PROP_RATE:
             self->rate = g_value_get_uint(value);
+            espeak_set_rate(self->speak, self->rate);
             break;
         case PROP_VOICE:
             self->voice = g_strdup(g_value_get_string(value));
+            espeak_set_voice(self->speak, self->voice);
             break;
         default:
             G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
@@ -238,15 +204,12 @@ gst_espeak_set_property (GObject *object, guint prop_id,
 }
 
 static void
-gst_espeak_get_property (GObject * object, guint prop_id,
+gst_espeak_get_property(GObject * object, guint prop_id,
     GValue * value, GParamSpec * pspec)
 {
     GstEspeak *self = GST_ESPEAK(object);
 
     switch (prop_id) {
-        case PROP_TEXT:
-            g_value_set_string(value, self->text);
-            break;
         case PROP_PITCH:
             g_value_set_uint(value, self->pitch);
             break;
@@ -271,43 +234,37 @@ gst_espeak_get_property (GObject * object, guint prop_id,
 /******************************************************************************/
 
 static GstFlowReturn
-gst_espeak_create (GstBaseSrc * self_, guint64 offset, guint size,
-        GstBuffer ** buf)
+gst_espeak_create(GstBaseSrc * self_, guint64 offset, guint size,
+        GstBuffer **buf)
 {
     GstEspeak *self = GST_ESPEAK(self_);
 
-    gpointer ptr = espeak_hear(self->speak, offset, &size);
+    gpointer sound = espeak_hear(self->speak, size);
 
-    if (size == 0)
+    if (sound == NULL)
         return GST_FLOW_UNEXPECTED;
 
     *buf = gst_buffer_new();
-    GST_BUFFER_DATA (*buf) = ptr;
-    GST_BUFFER_SIZE (*buf) = size;
+    GST_BUFFER_DATA(*buf) = sound;
+    GST_BUFFER_SIZE(*buf) = size;
 
     return GST_FLOW_OK;
 }
 
 static gboolean
-gst_espeak_start (GstBaseSrc * self_)
+gst_espeak_start(GstBaseSrc * self_)
 {
-    GstEspeak *self = GST_ESPEAK(self_);
-
-    if (self->text == NULL || self->text[0] == 0)
-        return FALSE;
-
-    return espeak_say(self->speak, self->text, self->voice, self->pitch,
-            self->rate);
+    return TRUE;
 }
 
 static gboolean
-gst_espeak_stop (GstBaseSrc * self)
+gst_espeak_stop(GstBaseSrc * self)
 {
     return TRUE;
 }
 
 static gboolean
-gst_espeak_is_seekable (GstBaseSrc * src)
+gst_espeak_is_seekable(GstBaseSrc * src)
 {
     return FALSE;
 }
@@ -334,13 +291,6 @@ gst_espeak_uri_get_protocols(void)
     return protocols;
 }
 
-static const gchar *
-gst_espeak_uri_get_uri(GstURIHandler *handler)
-{
-    GstEspeak *self = GST_ESPEAK(handler);
-    return self->uri;
-}
-
 static gboolean
 gst_espeak_uri_set_uri(GstURIHandler *handler, const gchar *uri)
 {
@@ -357,10 +307,10 @@ gst_espeak_uri_set_uri(GstURIHandler *handler, const gchar *uri)
     if (!text)
         return FALSE;
 
-    ret = gst_espeak_set_text(GST_ESPEAK(handler), text);
+    espeak_say(GST_ESPEAK(handler)->speak, text);
     g_free (text);
 
-    return ret;
+    return TRUE;
 }
 
 static void
@@ -370,7 +320,6 @@ gst_espeak_uri_handler_init(gpointer g_iface, gpointer iface_data)
 
     iface->get_type = gst_espeak_uri_get_type;
     iface->get_protocols = gst_espeak_uri_get_protocols;
-    iface->get_uri = gst_espeak_uri_get_uri;
     iface->set_uri = gst_espeak_uri_set_uri;
 }
 
diff --git a/src/gstespeak.h b/src/gstespeak.h
index a0776aa..499270b 100644
--- a/src/gstespeak.h
+++ b/src/gstespeak.h
@@ -37,14 +37,12 @@ G_BEGIN_DECLS
 
 typedef struct _GstEspeak      GstEspeak;
 typedef struct _GstEspeakClass GstEspeakClass;
-struct Espeak;
+struct _Espeak;
 
 struct _GstEspeak
 {
     GstAudioSrc parent;
-    struct Espeak *speak;
-    gchar *text;
-    gchar *uri;
+    struct _Espeak *speak;
     guint pitch;
     guint rate;
     gchar *voice;
diff --git a/src/spin.c b/src/spin.c
new file mode 100644
index 0000000..8d03ca9
--- /dev/null
+++ b/src/spin.c
@@ -0,0 +1,321 @@
+/*
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <glib.h>
+#include <gio/gio.h>
+#include <gst/gst.h>
+
+#define SPIN_QUEUE_SIZE 2
+#define SPIN_FRAME_SIZE 128
+
+#include "text.h"
+
+typedef void (*EspeakCallBack)(const gchar*, GMemoryOutputStream*, gpointer);
+
+typedef enum
+{
+    IN      = 1,
+    PROCESS = 2,
+    OUT     = 4,
+    PLAY    = 8
+} SpinState;
+
+typedef enum
+{
+    CLOSE     = 1,
+    INPROCESS = 2
+} ContextState;
+
+typedef struct
+{
+    SpinState state;
+    Text text;
+    GMemoryOutputStream *sound;
+    gsize sound_pos;
+} Espin;
+
+typedef struct 
+{
+    pthread_mutex_t lock;
+    pthread_cond_t cond;
+    ContextState state;
+
+    Espin queue[SPIN_QUEUE_SIZE];
+    Espin *in;
+    Espin *process;
+    Espin *out;
+
+    GSList *in_queue;
+    GSList *process_chunk;
+    gpointer closure;
+} Econtext;
+
+static inline void
+spinning(Espin *base, Espin **i)
+{
+    if (++(*i) == base + SPIN_QUEUE_SIZE)
+        *i = base;
+}
+
+static void process_push(Econtext*);
+
+// -----------------------------------------------------------------------------
+
+Econtext*
+spin_new(gpointer closure)
+{
+    Econtext *self = g_new0(Econtext, 1);
+    gint i;
+
+    for (i = SPIN_QUEUE_SIZE; i--;)
+    {
+        self->queue[i].sound = G_MEMORY_OUTPUT_STREAM(
+                g_memory_output_stream_new(NULL, 0, realloc, free));
+        self->queue[i].state = IN;
+    }
+
+    self->in = self->queue;
+    self->process = self->queue;
+    self->out = self->queue;
+
+    self->process_chunk = g_slist_alloc();
+    self->process_chunk->data = self;
+    self->closure = closure;
+
+    pthread_mutex_init(&self->lock, NULL);
+    pthread_cond_init(&self->cond, NULL);
+
+    GST_DEBUG("[%p]", self);
+
+    return self;
+}
+
+void
+spin_unref(Econtext *self)
+{
+    GST_DEBUG("[%p]", self);
+
+    gint i;
+
+    for (i = SPIN_QUEUE_SIZE; i--;)
+    {
+        g_output_stream_close(G_OUTPUT_STREAM(self->queue[i].sound),
+                NULL, NULL);
+        g_object_unref(self->queue[i].sound);
+    }
+
+    pthread_cond_destroy(&self->cond);
+    pthread_mutex_destroy(&self->lock);
+
+    g_slist_free(self->process_chunk);
+
+    g_free(self);
+    memset(self, 0, sizeof(Econtext));
+}
+
+// in/out ----------------------------------------------------------------------
+
+void
+spin_in(Econtext *self, const gchar *str_)
+{
+    GST_DEBUG("[%p] str=%s", self, str_);
+
+    if (str_ == NULL || *str_ == 0)
+        return;
+
+    Text *str = string_new(str_);
+
+    if (self->in_queue)
+    {
+        self->in_queue = g_slist_append(self->in_queue, str);
+        return;
+    }
+
+    gsize orig_frame_len = str->frame_len;
+
+    pthread_mutex_lock(&self->lock);
+
+    while (str->frame_len && self->in->state == IN)
+    {
+        Espin *spin = self->in;
+
+        GST_DEBUG("[%p] str->offset=%ld str->frame_len=%ld "
+                  "spin->text.offset=%ld spin->text.frame_len=%ld", self,
+                str->offset, str->frame_len,
+                spin->text.offset, spin->text.frame_len);
+
+        string_chunk(str, &spin->text, SPIN_FRAME_SIZE);
+        spin->state = PROCESS;
+
+        GST_DEBUG("[%p] str->offset=%ld str->frame_len=%ld "
+                  "spin->text.offset=%ld spin->text.frame_len=%ld", self,
+                str->offset, str->frame_len,
+                spin->text.offset, spin->text.frame_len);
+
+        spinning(self->queue, &self->in);
+    }
+
+    if ((orig_frame_len != str->frame_len) && (self->state & INPROCESS) == 0)
+    {
+        GST_DEBUG("[%p] orig_frame_len=%ld str->len=%ld", self, orig_frame_len,
+                str->len);
+
+        self->state |= INPROCESS;
+        process_push(self);
+    }
+
+    pthread_mutex_unlock(&self->lock);
+
+    if (!string_nil(str))
+        self->in_queue = g_slist_append(self->in_queue, str);
+}
+
+gpointer
+spin_out(Econtext *self, gsize *size_to_play)
+{
+    GST_DEBUG("[%p] size_to_play=%d", self, *size_to_play);
+
+    gpointer out = NULL;
+    pthread_mutex_lock(&self->lock);
+
+    for (;;)
+    {
+        while ((self->state & CLOSE) == 0 && (self->out->state & (PLAY|OUT))
+                == 0)
+            pthread_cond_wait(&self->cond, &self->lock);
+
+        GST_DEBUG("[%p] self->state=%d self->out->state=%d", self,
+                self->state, self->out->state);
+
+        if (self->state & CLOSE)
+            break;
+
+        Espin *spin = self->out;
+        gsize spin_size = g_memory_output_stream_get_data_size(spin->sound);
+
+        if (spin->state == PLAY && spin->sound_pos >= spin_size)
+        {
+            spin->state = IN;
+            string_unref(&spin->text);
+            spinning(self->queue, &self->out);
+
+            GST_DEBUG("[%p] self->out->state=%d", self, self->out->state);
+
+            continue;
+        }
+
+        spin->state = PLAY;
+        *size_to_play = MIN(*size_to_play, spin_size);
+
+        out = (guchar*)g_memory_output_stream_get_data(spin->sound) +
+                spin->sound_pos;
+
+        spin->sound_pos += *size_to_play;
+
+        GST_DEBUG("[%p] *size_to_play=%ld spin_size=%ld tell=%ld",
+                self, *size_to_play, spin_size, spin->sound_pos);
+
+        break;
+    }
+
+    pthread_mutex_unlock(&self->lock);
+
+    return out;
+}
+
+// process ----------------------------------------------------------------------
+
+static pthread_t process_tid;
+static pthread_mutex_t process_lock = PTHREAD_MUTEX_INITIALIZER;
+static pthread_cond_t process_cond = PTHREAD_COND_INITIALIZER;
+static GSList *process_queue = NULL;
+static EspeakCallBack process_espeak_cb = NULL;
+
+static void*
+process(void *data)
+{
+    pthread_mutex_lock(&process_lock);
+
+    for (;;)
+    {
+        while (process_queue == NULL)
+            pthread_cond_wait(&process_cond, &process_lock);
+
+        while (process_queue)
+        {
+            Econtext *context = (Econtext*)process_queue->data;
+            Espin *spin = context->process;
+
+            process_queue = g_slist_remove_link(process_queue, process_queue);
+            gboolean next = FALSE;
+
+            pthread_mutex_unlock(&process_lock);
+                gchar *text = spin->text.body + spin->text.offset;
+                gchar last_char = text[spin->text.frame_len];
+                text[spin->text.frame_len] = 0;
+
+                GST_DEBUG("[%p] text=%s", context, text);
+
+                g_seekable_seek(G_SEEKABLE(spin->sound), 0, G_SEEK_SET,
+                        NULL, NULL);
+                process_espeak_cb(text, spin->sound, context->closure);
+                spin->sound_pos = 0;
+
+                text[spin->text.frame_len] = last_char;
+
+                pthread_mutex_lock(&context->lock);
+                    spin->state = OUT;
+                    spinning(context->queue, &context->process);
+                    next = context->process->state == PROCESS;
+                    if (!next)
+                        context->state |= INPROCESS;
+                pthread_mutex_unlock(&context->lock);
+            pthread_mutex_lock(&process_lock);
+
+            if (next)
+                process_queue = g_slist_concat(process_queue,
+                        context->process_chunk);
+        }
+    }
+
+    pthread_mutex_unlock(&process_lock);
+    return NULL;
+}
+
+void
+spin_init(EspeakCallBack espeak_cb)
+{
+    process_espeak_cb = espeak_cb;
+
+    pthread_attr_t attr;
+    g_assert(pthread_attr_init(&attr) == 0);
+    g_assert(pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_DETACHED) == 0);
+    g_assert(pthread_create(&process_tid, &attr, process, NULL) == 0);
+    g_assert(pthread_attr_destroy(&attr) == 0);
+}
+
+static void
+process_push(Econtext *context)
+{
+    pthread_mutex_lock(&process_lock);
+    process_queue = g_slist_concat(process_queue, context->process_chunk);
+    pthread_cond_signal(&process_cond);
+    pthread_mutex_unlock(&process_lock);
+}
diff --git a/src/spin.h b/src/spin.h
new file mode 100644
index 0000000..6158e52
--- /dev/null
+++ b/src/spin.h
@@ -0,0 +1,32 @@
+/*
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef SPIN_H
+#define SPIN_H
+
+struct _Econtext;
+typedef struct _Econtext Econtext;
+
+typedef void (*EspeakCallBack)(const gchar*, GMemoryOutputStream*, gpointer);
+
+void                spin_init(EspeakCallBack);
+struct _Econtext*   spin_new();
+void                spin_unref(struct _Econtext*);
+void                spin_in(struct _Econtext*, const gchar *str);
+gpointer            spin_out(struct _Econtext*, gsize *size_to_play);
+
+#endif
diff --git a/src/text.h b/src/text.h
new file mode 100644
index 0000000..0261848
--- /dev/null
+++ b/src/text.h
@@ -0,0 +1,107 @@
+/*
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#ifndef TEXT_H
+#define TEXT_H
+
+#include <string.h>
+
+typedef struct
+{
+    goffset offset;
+    gsize frame_len;
+    gsize len;
+    gchar *body;
+} Text;
+
+inline Text*
+string_new(const gchar *src)
+{
+    if (!src)
+        return NULL;
+
+    gsize len = strlen(src);
+
+    Text *out = (Text*)g_malloc(sizeof(Text) + len + 1);
+    gchar *body = (gchar*)out + sizeof(Text);
+
+    out->offset = 0;
+    out->frame_len = len;
+    out->len = len;
+    out->body = body;
+
+    memcpy(body, src, len + 1);
+
+    GST_DEBUG("[%p] len=%ld", out, len);
+
+    return out;
+}
+
+inline void
+string_chunk(Text *src, Text *dst, gsize len)
+{
+    memcpy(dst, src, sizeof(Text));
+
+    gsize dst_len = MIN(len, src->frame_len);
+    gchar *dst_last = dst->body + dst->offset + dst_len;
+    gchar *i;
+
+    if (dst_len < src->frame_len)
+        for (i = dst_last; dst_len; --dst_len, --i)
+            if (g_ascii_isspace(*i))
+                break;
+
+    if (dst_len)
+        dst->frame_len = dst_len;
+    else
+    {
+        dst_last = g_utf8_prev_char(dst_last + 1);
+        dst->frame_len = dst_last - (dst->body + dst->offset);
+    }
+
+    src->offset += dst->frame_len;
+    src->frame_len -= dst->frame_len;
+
+    GST_DEBUG("[%p] len=%ld dst_len=%ld dst_last=%ld", src, len, dst_len,
+            dst_last-dst->body);
+}
+
+inline gboolean
+string_nil(Text *str)
+{
+    return str->frame_len == 0;
+}
+
+inline void
+string_unref(Text *str)
+{
+    if (string_nil(str))
+        return;
+
+    gpointer data = NULL;
+
+    if (str->offset + str->frame_len >= str->len)
+        data = str->body - sizeof(Text);
+
+    memset(str, 0, sizeof(Text));
+
+    GST_DEBUG("[%p]", data);
+
+    g_free(data);
+}
+
+#endif