Sat Aug 6 00:40:05 2011

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

Defines

#define AST_SPEECH_HAVE_RESULTS   (1 << 2)
#define AST_SPEECH_QUIET   (1 << 0)
#define AST_SPEECH_SPOKE   (1 << 1)
#define AST_SPEECH_STATE_DONE   3
#define AST_SPEECH_STATE_NOT_READY   0
#define AST_SPEECH_STATE_READY   1
#define AST_SPEECH_STATE_WAIT   2

Enumerations

enum  ast_speech_results_type { AST_SPEECH_RESULTS_TYPE_NORMAL = 0, AST_SPEECH_RESULTS_TYPE_NBEST }

Functions

int ast_speech_change (struct ast_speech *speech, 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, char *grammar_name)
 Activate a grammar on a speech structure.
int ast_speech_grammar_deactivate (struct ast_speech *speech, char *grammar_name)
 Deactivate a grammar on a speech structure.
int ast_speech_grammar_load (struct ast_speech *speech, char *grammar_name, char *grammar)
 Load a grammar on a speech structure (not globally).
int ast_speech_grammar_unload (struct ast_speech *speech, char *grammar_name)
 Unload a grammar.
ast_speechast_speech_new (char *engine_name, int format)
 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 (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.


Define Documentation

#define AST_SPEECH_HAVE_RESULTS   (1 << 2)

Definition at line 33 of file speech.h.

Referenced by ast_speech_start().

#define AST_SPEECH_QUIET   (1 << 0)

Definition at line 31 of file speech.h.

Referenced by ast_speech_start(), and speech_background().

#define AST_SPEECH_SPOKE   (1 << 1)

Definition at line 32 of file speech.h.

Referenced by ast_speech_change_state(), ast_speech_start(), and speech_read().

#define AST_SPEECH_STATE_DONE   3

Definition at line 39 of file speech.h.

Referenced by speech_background().

#define AST_SPEECH_STATE_NOT_READY   0

Definition at line 36 of file speech.h.

Referenced by ast_speech_new(), and speech_background().

#define AST_SPEECH_STATE_READY   1

Definition at line 37 of file speech.h.

Referenced by ast_speech_dtmf(), ast_speech_write(), and speech_background().

#define AST_SPEECH_STATE_WAIT   2

Definition at line 38 of file speech.h.

Referenced by ast_speech_change_state(), and speech_background().


Enumeration Type Documentation

enum ast_speech_results_type

Enumerator:
AST_SPEECH_RESULTS_TYPE_NORMAL 
AST_SPEECH_RESULTS_TYPE_NBEST 

Definition at line 41 of file speech.h.


Function Documentation

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

Change an engine specific attribute.

Definition at line 212 of file res_speech.c.

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

Referenced by speech_engine_write().

00213 {
00214    int res = 0;
00215 
00216    if (speech->engine->change != NULL) {
00217       res = speech->engine->change(speech, name, value);
00218    }
00219 
00220    return res;
00221 }

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 313 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().

00314 {
00315    int res = 0;
00316 
00317    speech->results_type = results_type;
00318 
00319    if (speech->engine->change_results_type)
00320       res = speech->engine->change_results_type(speech, results_type);
00321 
00322    return res;
00323 }

int ast_speech_change_state ( struct ast_speech speech,
int  state 
)

Change state of a speech structure.

Definition at line 296 of file res_speech.c.

References ast_set_flag, AST_SPEECH_SPOKE, and AST_SPEECH_STATE_WAIT.

Referenced by ast_speech_new(), and speech_background().

00297 {
00298    int res = 0;
00299 
00300    switch (state) {
00301    case AST_SPEECH_STATE_WAIT:
00302       /* The engine heard audio, so they spoke */
00303       ast_set_flag(speech, AST_SPEECH_SPOKE);
00304    default:
00305       speech->state = state;
00306       break;
00307    }
00308 
00309    return res;
00310 }

int ast_speech_destroy ( struct ast_speech speech  ) 

Destroy a speech structure.

Definition at line 266 of file res_speech.c.

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

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

00267 {
00268    int res = 0;
00269 
00270    /* Call our engine so we are destroyed properly */
00271    speech->engine->destroy(speech);
00272 
00273    /* Deinitialize the lock */
00274    ast_mutex_destroy(&speech->lock);
00275 
00276    /* If results exist on the speech structure, destroy them */
00277    if (speech->results != NULL) {
00278       ast_speech_results_free(speech->results);
00279       speech->results = NULL;
00280    }
00281 
00282    /* If a processing sound is set - free the memory used by it */
00283    if (speech->processing_sound != NULL) {
00284       free(speech->processing_sound);
00285       speech->processing_sound = NULL;
00286    }
00287 
00288    /* Aloha we are done */
00289    free(speech);
00290    speech = NULL;
00291 
00292    return res;
00293 }

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

Signal to the engine that DTMF was received.

Definition at line 197 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().

00198 {
00199    int res = 0;
00200 
00201    if (speech->state != AST_SPEECH_STATE_READY)
00202       return -1;
00203 
00204    if (speech->engine->dtmf != NULL) {
00205       res = speech->engine->dtmf(speech, dtmf);
00206    }
00207 
00208    return res;
00209 }

int ast_speech_grammar_activate ( struct ast_speech speech,
char *  grammar_name 
)

Activate a grammar on a speech structure.

Definition at line 71 of file res_speech.c.

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

Referenced by speech_activate().

00072 {
00073    int res = 0;
00074 
00075    if (speech->engine->activate != NULL) {
00076       res = speech->engine->activate(speech, grammar_name);
00077    }
00078 
00079    return res;
00080 }

int ast_speech_grammar_deactivate ( struct ast_speech speech,
char *  grammar_name 
)

Deactivate a grammar on a speech structure.

Definition at line 83 of file res_speech.c.

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

Referenced by speech_deactivate().

00084 {
00085    int res = 0;
00086 
00087         if (speech->engine->deactivate != NULL) {
00088                 res = speech->engine->deactivate(speech, grammar_name);
00089         }
00090 
00091    return res;
00092 }

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

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

Definition at line 95 of file res_speech.c.

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

Referenced by speech_load().

00096 {
00097    int res = 0;
00098 
00099    if (speech->engine->load != NULL) {
00100       res = speech->engine->load(speech, grammar_name, grammar);
00101    }
00102 
00103    return res;
00104 }

int ast_speech_grammar_unload ( struct ast_speech speech,
char *  grammar_name 
)

Unload a grammar.

Definition at line 107 of file res_speech.c.

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

Referenced by speech_unload().

00108 {
00109         int res = 0;
00110 
00111         if (speech->engine->unload != NULL) {
00112                 res = speech->engine->unload(speech, grammar_name);
00113         }
00114 
00115         return res;
00116 }

struct ast_speech* ast_speech_new ( char *  engine_name,
int  format 
)

Create a new speech structure.

Definition at line 224 of file res_speech.c.

References ast_calloc, ast_mutex_destroy(), ast_mutex_init(), ast_speech_change_state(), AST_SPEECH_STATE_NOT_READY, ast_speech_engine::create, ast_speech::engine, find_engine(), and free.

Referenced by speech_create().

00225 {
00226    struct ast_speech_engine *engine = NULL;
00227    struct ast_speech *new_speech = NULL;
00228 
00229    /* Try to find the speech recognition engine that was requested */
00230    engine = find_engine(engine_name);
00231    if (engine == NULL) {
00232       /* Invalid engine or no engine available */
00233       return NULL;
00234    }
00235 
00236    /* Allocate our own speech structure, and try to allocate a structure from the engine too */
00237    new_speech = ast_calloc(1, sizeof(*new_speech));
00238    if (new_speech == NULL) {
00239       /* Ran out of memory while trying to allocate some for a speech structure */
00240       return NULL;
00241    }
00242 
00243    /* Initialize the lock */
00244    ast_mutex_init(&new_speech->lock);
00245 
00246    /* Make sure no results are present */
00247    new_speech->results = NULL;
00248 
00249    /* Copy over our engine pointer */
00250    new_speech->engine = engine;
00251 
00252    /* We are not ready to accept audio yet */
00253    ast_speech_change_state(new_speech, AST_SPEECH_STATE_NOT_READY);
00254 
00255    /* Pass ourselves to the engine so they can set us up some more and if they error out then do not create a structure */
00256    if (engine->create(new_speech)) {
00257       ast_mutex_destroy(&new_speech->lock);
00258       free(new_speech);
00259       new_speech = NULL;
00260    }
00261 
00262    return new_speech;
00263 }

int ast_speech_register ( struct ast_speech_engine engine  ) 

Register a speech recognition engine.

Definition at line 326 of file res_speech.c.

References AST_LIST_INSERT_HEAD, AST_LIST_LOCK, AST_LIST_UNLOCK, ast_verbose(), default_engine, find_engine(), ast_speech_engine::name, option_verbose, and VERBOSE_PREFIX_2.

00327 {
00328    struct ast_speech_engine *existing_engine = NULL;
00329    int res = 0;
00330 
00331    existing_engine = find_engine(engine->name);
00332    if (existing_engine != NULL) {
00333       /* Engine already loaded */
00334       return -1;
00335    }
00336 
00337    if (option_verbose > 1)
00338       ast_verbose(VERBOSE_PREFIX_2 "Registered speech recognition engine '%s'\n", engine->name);
00339 
00340    /* Add to the engine linked list and make default if needed */
00341    AST_LIST_LOCK(&engines);
00342    AST_LIST_INSERT_HEAD(&engines, engine, list);
00343    if (default_engine == NULL) {
00344       default_engine = engine;
00345       if (option_verbose > 1)
00346          ast_verbose(VERBOSE_PREFIX_2 "Made '%s' the default speech recognition engine\n", engine->name);
00347    }
00348    AST_LIST_UNLOCK(&engines);
00349 
00350    return res;
00351 }

int ast_speech_results_free ( struct ast_speech_result result  ) 

Free a set of results.

Definition at line 131 of file res_speech.c.

References free, ast_speech_result::grammar, ast_speech_result::next, and ast_speech_result::text.

Referenced by ast_speech_destroy(), and ast_speech_start().

00132 {
00133    struct ast_speech_result *current_result = result, *prev_result = NULL;
00134    int res = 0;
00135 
00136    while (current_result != NULL) {
00137       prev_result = current_result;
00138       /* Deallocate what we can */
00139       if (current_result->text != NULL) {
00140          free(current_result->text);
00141          current_result->text = NULL;
00142       }
00143       if (current_result->grammar != NULL) {
00144          free(current_result->grammar);
00145          current_result->grammar = NULL;
00146       }
00147       /* Move on and then free ourselves */
00148       current_result = current_result->next;
00149       free(prev_result);
00150       prev_result = NULL;
00151    }
00152 
00153    return res;
00154 }

struct ast_speech_result* ast_speech_results_get ( struct ast_speech speech  ) 

Get speech recognition results.

Definition at line 119 of file res_speech.c.

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

Referenced by speech_background().

00120 {
00121    struct ast_speech_result *result = NULL;
00122 
00123    if (speech->engine->get != NULL) {
00124       result = speech->engine->get(speech);
00125    }
00126 
00127    return result;
00128 }

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 157 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 speech_background(), and speech_start().

00158 {
00159 
00160    /* Clear any flags that may affect things */
00161    ast_clear_flag(speech, AST_SPEECH_SPOKE);
00162    ast_clear_flag(speech, AST_SPEECH_QUIET);
00163    ast_clear_flag(speech, AST_SPEECH_HAVE_RESULTS);
00164 
00165    /* If results are on the structure, free them since we are starting again */
00166    if (speech->results != NULL) {
00167       ast_speech_results_free(speech->results);
00168       speech->results = NULL;
00169    }
00170 
00171    /* If the engine needs to start stuff up, do it */
00172    if (speech->engine->start != NULL) {
00173       speech->engine->start(speech);
00174    }
00175 
00176    return;
00177 }

int ast_speech_unregister ( char *  engine_name  ) 

Unregister a speech recognition engine.

Definition at line 354 of file res_speech.c.

References AST_LIST_FIRST, AST_LIST_LOCK, AST_LIST_REMOVE_CURRENT, AST_LIST_TRAVERSE_SAFE_BEGIN, AST_LIST_TRAVERSE_SAFE_END, AST_LIST_UNLOCK, ast_verbose(), default_engine, ast_speech_engine::name, option_verbose, and VERBOSE_PREFIX_2.

00355 {
00356    struct ast_speech_engine *engine = NULL;
00357    int res = -1;
00358 
00359    if (engine_name == NULL) {
00360       return res;
00361    }
00362 
00363    AST_LIST_LOCK(&engines);
00364    AST_LIST_TRAVERSE_SAFE_BEGIN(&engines, engine, list) {
00365       if (!strcasecmp(engine->name, engine_name)) {
00366          /* We have our engine... removed it */
00367          AST_LIST_REMOVE_CURRENT(&engines, list);
00368          /* If this was the default engine, we need to pick a new one */
00369          if (default_engine == engine) {
00370             default_engine = AST_LIST_FIRST(&engines);
00371          }
00372          if (option_verbose > 1)
00373             ast_verbose(VERBOSE_PREFIX_2 "Unregistered speech recognition engine '%s'\n", engine_name);
00374          /* All went well */
00375          res = 0;
00376          break;
00377       }
00378    }
00379    AST_LIST_TRAVERSE_SAFE_END
00380    AST_LIST_UNLOCK(&engines);
00381 
00382    return res;
00383 }

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

Write audio to the speech engine.

Definition at line 180 of file res_speech.c.

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

Referenced by speech_background().

00181 {
00182    int res = 0;
00183 
00184    /* Make sure the speech engine is ready to accept audio */
00185    if (speech->state != AST_SPEECH_STATE_READY) {
00186       return -1;
00187    }
00188 
00189    if (speech->engine->write != NULL) {
00190       speech->engine->write(speech, data, len);
00191    }
00192 
00193    return res;
00194 }


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