Mon Oct 8 12:39:29 2012

Asterisk developer's documentation


speech.h File Reference

Generic Speech Recognition API. More...

Go to the source code of this file.

Data Structures

struct  ast_speech
struct  ast_speech_engine
struct  ast_speech_result

Enumerations

enum  ast_speech_flags { AST_SPEECH_QUIET = (1 << 0), AST_SPEECH_SPOKE = (1 << 1), AST_SPEECH_HAVE_RESULTS = (1 << 2) }
enum  ast_speech_results_type { AST_SPEECH_RESULTS_TYPE_NORMAL = 0, AST_SPEECH_RESULTS_TYPE_NBEST }
enum  ast_speech_states { AST_SPEECH_STATE_NOT_READY = 0, AST_SPEECH_STATE_READY, AST_SPEECH_STATE_WAIT, AST_SPEECH_STATE_DONE }

Functions

int ast_speech_change (struct ast_speech *speech, const char *name, const char *value)
 Change an engine specific attribute.
int ast_speech_change_results_type (struct ast_speech *speech, enum ast_speech_results_type results_type)
 Change the type of results we want.
int ast_speech_change_state (struct ast_speech *speech, int state)
 Change state of a speech structure.
int ast_speech_destroy (struct ast_speech *speech)
 Destroy a speech structure.
int ast_speech_dtmf (struct ast_speech *speech, const char *dtmf)
 Signal to the engine that DTMF was received.
int ast_speech_grammar_activate (struct ast_speech *speech, const char *grammar_name)
 Activate a grammar on a speech structure.
int ast_speech_grammar_deactivate (struct ast_speech *speech, const char *grammar_name)
 Deactivate a grammar on a speech structure.
int ast_speech_grammar_load (struct ast_speech *speech, const char *grammar_name, const char *grammar)
 Load a grammar on a speech structure (not globally).
int ast_speech_grammar_unload (struct ast_speech *speech, const char *grammar_name)
 Unload a grammar.
ast_speechast_speech_new (const char *engine_name, int formats)
 Create a new speech structure.
int ast_speech_register (struct ast_speech_engine *engine)
 Register a speech recognition engine.
int ast_speech_results_free (struct ast_speech_result *result)
 Free a set of results.
ast_speech_resultast_speech_results_get (struct ast_speech *speech)
 Get speech recognition results.
void ast_speech_start (struct ast_speech *speech)
 Indicate to the speech engine that audio is now going to start being written.
int ast_speech_unregister (const char *engine_name)
 Unregister a speech recognition engine.
int ast_speech_write (struct ast_speech *speech, void *data, int len)
 Write audio to the speech engine.


Detailed Description

Generic Speech Recognition API.

Definition in file speech.h.


Enumeration Type Documentation

enum ast_speech_flags

Enumerator:
AST_SPEECH_QUIET 
AST_SPEECH_SPOKE 
AST_SPEECH_HAVE_RESULTS 

Definition at line 31 of file speech.h.

00031                       {
00032    AST_SPEECH_QUIET = (1 << 0),        /* Quiet down output... they are talking */
00033    AST_SPEECH_SPOKE = (1 << 1),        /* Speaker spoke! */
00034    AST_SPEECH_HAVE_RESULTS = (1 << 2), /* Results are present */
00035 };

enum ast_speech_results_type

Enumerator:
AST_SPEECH_RESULTS_TYPE_NORMAL 
AST_SPEECH_RESULTS_TYPE_NBEST 

Definition at line 45 of file speech.h.

enum ast_speech_states

Enumerator:
AST_SPEECH_STATE_NOT_READY 
AST_SPEECH_STATE_READY 
AST_SPEECH_STATE_WAIT 
AST_SPEECH_STATE_DONE 

Definition at line 38 of file speech.h.

00038                        {
00039    AST_SPEECH_STATE_NOT_READY = 0, /* Not ready to accept audio */
00040    AST_SPEECH_STATE_READY, /* Accepting audio */
00041    AST_SPEECH_STATE_WAIT, /* Wait for results to become available */
00042    AST_SPEECH_STATE_DONE, /* Processing is all done */
00043 };


Function Documentation

int ast_speech_change ( struct ast_speech speech,
const char *  name,
const char *  value 
)

Change an engine specific attribute.

Definition at line 170 of file res_speech.c.

References ast_speech_engine::change, and ast_speech::engine.

Referenced by handle_speechset(), and speech_engine_write().

00171 {
00172    return (speech->engine->change ? speech->engine->change(speech, name, value) : -1);
00173 }

int ast_speech_change_results_type ( struct ast_speech speech,
enum ast_speech_results_type  results_type 
)

Change the type of results we want.

Definition at line 264 of file res_speech.c.

References ast_speech_engine::change_results_type, ast_speech::engine, and ast_speech::results_type.

Referenced by speech_results_type_write().

00265 {
00266    speech->results_type = results_type;
00267 
00268    return (speech->engine->change_results_type ? speech->engine->change_results_type(speech, results_type) : 0);
00269 }

int ast_speech_change_state ( struct ast_speech speech,
int  state 
)

Change state of a speech structure.

Definition at line 249 of file res_speech.c.

References ast_set_flag, AST_SPEECH_SPOKE, AST_SPEECH_STATE_WAIT, and ast_speech::state.

Referenced by ast_speech_new(), handle_speechrecognize(), and speech_background().

00250 {
00251    int res = 0;
00252 
00253    if (state == AST_SPEECH_STATE_WAIT) {
00254       /* The engine heard audio, so they spoke */
00255       ast_set_flag(speech, AST_SPEECH_SPOKE);
00256    }
00257 
00258    speech->state = state;
00259 
00260    return res;
00261 }

int ast_speech_destroy ( struct ast_speech speech  ) 

Destroy a speech structure.

Definition at line 224 of file res_speech.c.

References ast_free, ast_mutex_destroy, ast_speech_results_free(), ast_speech_engine::destroy, ast_speech::engine, ast_speech::lock, ast_speech::processing_sound, and ast_speech::results.

Referenced by destroy_callback(), handle_speechdestroy(), launch_asyncagi(), speech_background(), speech_create(), and speech_destroy().

00225 {
00226    int res = 0;
00227 
00228    /* Call our engine so we are destroyed properly */
00229    speech->engine->destroy(speech);
00230 
00231    /* Deinitialize the lock */
00232    ast_mutex_destroy(&speech->lock);
00233 
00234    /* If results exist on the speech structure, destroy them */
00235    if (speech->results)
00236       ast_speech_results_free(speech->results);
00237 
00238    /* If a processing sound is set - free the memory used by it */
00239    if (speech->processing_sound)
00240       ast_free(speech->processing_sound);
00241 
00242    /* Aloha we are done */
00243    ast_free(speech);
00244 
00245    return res;
00246 }

int ast_speech_dtmf ( struct ast_speech speech,
const char *  dtmf 
)

Signal to the engine that DTMF was received.

Definition at line 155 of file res_speech.c.

References AST_SPEECH_STATE_READY, ast_speech_engine::dtmf, ast_speech::engine, and ast_speech::state.

Referenced by speech_background().

00156 {
00157    int res = 0;
00158 
00159    if (speech->state != AST_SPEECH_STATE_READY)
00160       return -1;
00161 
00162    if (speech->engine->dtmf != NULL) {
00163       res = speech->engine->dtmf(speech, dtmf);
00164    }
00165 
00166    return res;
00167 }

int ast_speech_grammar_activate ( struct ast_speech speech,
const char *  grammar_name 
)

Activate a grammar on a speech structure.

Definition at line 67 of file res_speech.c.

References ast_speech_engine::activate, and ast_speech::engine.

Referenced by handle_speechactivategrammar(), and speech_activate().

00068 {
00069    return (speech->engine->activate ? speech->engine->activate(speech, grammar_name) : -1);
00070 }

int ast_speech_grammar_deactivate ( struct ast_speech speech,
const char *  grammar_name 
)

Deactivate a grammar on a speech structure.

Definition at line 73 of file res_speech.c.

References ast_speech_engine::deactivate, and ast_speech::engine.

Referenced by handle_speechdeactivategrammar(), and speech_deactivate().

00074 {
00075    return (speech->engine->deactivate ? speech->engine->deactivate(speech, grammar_name) : -1);
00076 }

int ast_speech_grammar_load ( struct ast_speech speech,
const char *  grammar_name,
const char *  grammar 
)

Load a grammar on a speech structure (not globally).

Definition at line 79 of file res_speech.c.

References ast_speech::engine, and ast_speech_engine::load.

Referenced by handle_speechloadgrammar(), and speech_load().

00080 {
00081    return (speech->engine->load ? speech->engine->load(speech, grammar_name, grammar) : -1);
00082 }

int ast_speech_grammar_unload ( struct ast_speech speech,
const char *  grammar_name 
)

Unload a grammar.

Definition at line 85 of file res_speech.c.

References ast_speech::engine, and ast_speech_engine::unload.

Referenced by handle_speechunloadgrammar(), and speech_unload().

00086 {
00087    return (speech->engine->unload ? speech->engine->unload(speech, grammar_name) : -1);
00088 }

struct ast_speech* ast_speech_new ( const char *  engine_name,
int  formats 
)

Create a new speech structure.

Definition at line 176 of file res_speech.c.

References ast_best_codec(), ast_calloc, AST_FORMAT_SLINEAR, ast_free, ast_mutex_destroy, ast_mutex_init, ast_speech_change_state(), AST_SPEECH_STATE_NOT_READY, ast_speech_engine::create, ast_speech::engine, find_engine(), format, and ast_speech_engine::formats.

Referenced by handle_speechcreate(), and speech_create().

00177 {
00178    struct ast_speech_engine *engine = NULL;
00179    struct ast_speech *new_speech = NULL;
00180    int format = AST_FORMAT_SLINEAR;
00181 
00182    /* Try to find the speech recognition engine that was requested */
00183    if (!(engine = find_engine(engine_name)))
00184       return NULL;
00185 
00186    /* Before even allocating the memory below do some codec negotiation, we choose the best codec possible and fall back to signed linear if possible */
00187    if ((format = (engine->formats & formats)))
00188       format = ast_best_codec(format);
00189    else if ((engine->formats & AST_FORMAT_SLINEAR))
00190       format = AST_FORMAT_SLINEAR;
00191    else
00192       return NULL;
00193 
00194    /* Allocate our own speech structure, and try to allocate a structure from the engine too */
00195    if (!(new_speech = ast_calloc(1, sizeof(*new_speech))))
00196       return NULL;
00197 
00198    /* Initialize the lock */
00199    ast_mutex_init(&new_speech->lock);
00200 
00201    /* Make sure no results are present */
00202    new_speech->results = NULL;
00203 
00204    /* Copy over our engine pointer */
00205    new_speech->engine = engine;
00206 
00207    /* Can't forget the format audio is going to be in */
00208    new_speech->format = format;
00209 
00210    /* We are not ready to accept audio yet */
00211    ast_speech_change_state(new_speech, AST_SPEECH_STATE_NOT_READY);
00212 
00213    /* Pass ourselves to the engine so they can set us up some more and if they error out then do not create a structure */
00214    if (engine->create(new_speech, format)) {
00215       ast_mutex_destroy(&new_speech->lock);
00216       ast_free(new_speech);
00217       new_speech = NULL;
00218    }
00219 
00220    return new_speech;
00221 }

int ast_speech_register ( struct ast_speech_engine engine  ) 

Register a speech recognition engine.

Definition at line 272 of file res_speech.c.

References ast_log(), AST_RWLIST_INSERT_HEAD, AST_RWLIST_UNLOCK, AST_RWLIST_WRLOCK, ast_verb, ast_speech_engine::create, default_engine, ast_speech_engine::destroy, ast_speech::engine, find_engine(), LOG_WARNING, ast_speech_engine::name, and ast_speech_engine::write.

00273 {
00274    int res = 0;
00275 
00276    /* Confirm the engine meets the minimum API requirements */
00277    if (!engine->create || !engine->write || !engine->destroy) {
00278       ast_log(LOG_WARNING, "Speech recognition engine '%s' did not meet minimum API requirements.\n", engine->name);
00279       return -1;
00280    }
00281 
00282    /* If an engine is already loaded with this name, error out */
00283    if (find_engine(engine->name)) {
00284       ast_log(LOG_WARNING, "Speech recognition engine '%s' already exists.\n", engine->name);
00285       return -1;
00286    }
00287 
00288    ast_verb(2, "Registered speech recognition engine '%s'\n", engine->name);
00289 
00290    /* Add to the engine linked list and make default if needed */
00291    AST_RWLIST_WRLOCK(&engines);
00292    AST_RWLIST_INSERT_HEAD(&engines, engine, list);
00293    if (!default_engine) {
00294       default_engine = engine;
00295       ast_verb(2, "Made '%s' the default speech recognition engine\n", engine->name);
00296    }
00297    AST_RWLIST_UNLOCK(&engines);
00298 
00299    return res;
00300 }

int ast_speech_results_free ( struct ast_speech_result result  ) 

Free a set of results.

Definition at line 97 of file res_speech.c.

References ast_free, AST_LIST_NEXT, ast_speech_result::grammar, and ast_speech_result::text.

Referenced by ast_speech_destroy(), and ast_speech_start().

00098 {
00099    struct ast_speech_result *current_result = result, *prev_result = NULL;
00100    int res = 0;
00101 
00102    while (current_result != NULL) {
00103       prev_result = current_result;
00104       /* Deallocate what we can */
00105       if (current_result->text != NULL) {
00106          ast_free(current_result->text);
00107          current_result->text = NULL;
00108       }
00109       if (current_result->grammar != NULL) {
00110          ast_free(current_result->grammar);
00111          current_result->grammar = NULL;
00112       }
00113       /* Move on and then free ourselves */
00114       current_result = AST_LIST_NEXT(current_result, list);
00115       ast_free(prev_result);
00116       prev_result = NULL;
00117    }
00118 
00119    return res;
00120 }

struct ast_speech_result* ast_speech_results_get ( struct ast_speech speech  ) 

Get speech recognition results.

Definition at line 91 of file res_speech.c.

References ast_speech::engine, and ast_speech_engine::get.

Referenced by handle_speechrecognize(), and speech_background().

00092 {
00093    return (speech->engine->get ? speech->engine->get(speech) : NULL);
00094 }

void ast_speech_start ( struct ast_speech speech  ) 

Indicate to the speech engine that audio is now going to start being written.

Definition at line 123 of file res_speech.c.

References ast_clear_flag, AST_SPEECH_HAVE_RESULTS, AST_SPEECH_QUIET, ast_speech_results_free(), AST_SPEECH_SPOKE, ast_speech::engine, ast_speech::results, and ast_speech_engine::start.

Referenced by handle_speechrecognize(), speech_background(), and speech_start().

00124 {
00125 
00126    /* Clear any flags that may affect things */
00127    ast_clear_flag(speech, AST_SPEECH_SPOKE);
00128    ast_clear_flag(speech, AST_SPEECH_QUIET);
00129    ast_clear_flag(speech, AST_SPEECH_HAVE_RESULTS);
00130 
00131    /* If results are on the structure, free them since we are starting again */
00132    if (speech->results) {
00133       ast_speech_results_free(speech->results);
00134       speech->results = NULL;
00135    }
00136 
00137    /* If the engine needs to start stuff up, do it */
00138    if (speech->engine->start)
00139       speech->engine->start(speech);
00140 
00141    return;
00142 }

int ast_speech_unregister ( const char *  engine_name  ) 

Unregister a speech recognition engine.

Definition at line 303 of file res_speech.c.

References AST_RWLIST_FIRST, AST_RWLIST_REMOVE_CURRENT, AST_RWLIST_TRAVERSE_SAFE_BEGIN, AST_RWLIST_TRAVERSE_SAFE_END, AST_RWLIST_UNLOCK, AST_RWLIST_WRLOCK, ast_strlen_zero(), ast_verb, default_engine, and ast_speech_engine::name.

00304 {
00305    struct ast_speech_engine *engine = NULL;
00306    int res = -1;
00307 
00308    if (ast_strlen_zero(engine_name))
00309       return -1;
00310 
00311    AST_RWLIST_WRLOCK(&engines);
00312    AST_RWLIST_TRAVERSE_SAFE_BEGIN(&engines, engine, list) {
00313       if (!strcasecmp(engine->name, engine_name)) {
00314          /* We have our engine... removed it */
00315          AST_RWLIST_REMOVE_CURRENT(list);
00316          /* If this was the default engine, we need to pick a new one */
00317          if (engine == default_engine) {
00318             default_engine = AST_RWLIST_FIRST(&engines);
00319          }
00320          ast_verb(2, "Unregistered speech recognition engine '%s'\n", engine_name);
00321          /* All went well */
00322          res = 0;
00323          break;
00324       }
00325    }
00326    AST_RWLIST_TRAVERSE_SAFE_END;
00327    AST_RWLIST_UNLOCK(&engines);
00328 
00329    return res;
00330 }

int ast_speech_write ( struct ast_speech speech,
void *  data,
int  len 
)

Write audio to the speech engine.

Definition at line 145 of file res_speech.c.

References AST_SPEECH_STATE_READY, ast_speech::engine, ast_speech::state, and ast_speech_engine::write.

Referenced by handle_speechrecognize(), and speech_background().

00146 {
00147    /* Make sure the speech engine is ready to accept audio */
00148    if (speech->state != AST_SPEECH_STATE_READY)
00149       return -1;
00150 
00151    return speech->engine->write(speech, data, len);
00152 }


Generated on Mon Oct 8 12:39:29 2012 for Asterisk - The Open Source Telephony Project by  doxygen 1.4.7