1 /* Copyright (C) 2007 Andre Noll <maan@tuebingen.mpg.de>, see file COPYING. */
3 /** \file mood.c Paraslash's mood handling functions. */
17 * Mood parser API. It's overkill to have an own header file for
18 * these declarations as they are only needed in this .c file.
21 int mp_init(const char *definition, int nbytes, struct mp_context **result,
23 bool mp_eval_row(const struct osl_row *aft_row, struct mp_context *ctx);
24 void mp_shutdown(struct mp_context *ctx);
27 * Contains statistical data of the currently admissible audio files.
29 * It is used to assign normalized score values to each admissible audio file.
31 struct afs_statistics {
32 /** Sum of num played over all admissible files. */
33 int64_t num_played_sum;
34 /** Sum of last played times over all admissible files. */
35 int64_t last_played_sum;
36 /** Quadratic deviation of num played count. */
37 int64_t num_played_qd;
38 /** Quadratic deviation of last played time. */
39 int64_t last_played_qd;
40 /** Correction factor for the num played score. */
41 int64_t num_played_correction;
42 /** Correction factor for the last played score. */
43 int64_t last_played_correction;
44 /** Common divisor of the correction factors. */
45 int64_t normalization_divisor;
46 /** Number of admissible files */
51 * Stores an instance of a loaded mood (parser and statistics).
53 * A structure of this type is allocated and initialized when a mood is loaded.
55 struct mood_instance {
56 /** NULL means that this is the "dummy" mood. */
58 /** Bison's abstract syntax tree, used to determine admissibility. */
59 struct mp_context *parser_context;
60 /** To compute the score. */
61 struct afs_statistics stats;
65 * If current_mood is NULL then no mood is currently loaded. If
66 * current_mood->name is NULL, the current mood is the dummy mood.
68 * The statistics are adjusted dynamically through this pointer as files are
69 * added, removed or played.
71 static struct mood_instance *current_mood;
74 * Find the position of the most-significant set bit.
76 * Copied and slightly adapted from the linux source tree, version 4.9.39
79 __a_const static uint32_t fls64(uint64_t v)
82 const uint64_t ones = ~(uint64_t)0U;
84 if ((v & (ones << 32)) == 0) {
88 if ((v & (ones << (64 - 16))) == 0) {
92 if ((v & (ones << (64 - 8))) == 0) {
96 if ((v & (ones << (64 - 4))) == 0) {
100 if ((v & (ones << (64 - 2))) == 0) {
104 if ((v & (ones << (64 - 1))) == 0)
110 * Compute the integer square root floor(sqrt(x)).
112 * Taken 2007 from the linux source tree.
114 __a_const static uint64_t int_sqrt(uint64_t x)
116 uint64_t op = x, res = 0, one = 1;
118 one = one << (fls64(x) & ~one);
120 if (op >= res + one) {
121 op = op - (res + one);
130 static void destroy_mood(struct mood_instance *m)
134 mp_shutdown(m->parser_context);
139 static struct mood_instance *alloc_new_mood(const char *name)
141 struct mood_instance *m = zalloc(sizeof(*m));
144 m->name = para_strdup(name);
145 m->stats.normalization_divisor = 1;
149 static int init_mood_parser(const char *mood_name, struct mood_instance **m,
152 struct osl_object mood_def;
157 *err = make_message("empty mood name\n");
158 return -ERRNO_TO_PARA_ERROR(EINVAL);
160 ret = mood_get_def_by_name(mood_name, &mood_def);
163 *err = make_message("could not read mood definition\n");
166 *m = alloc_new_mood(mood_name);
167 PARA_INFO_LOG("loading mood %s\n", mood_name);
168 ret = mp_init(mood_def.data, mood_def.size, &(*m)->parser_context, err);
169 osl_close_disk_object(&mood_def);
175 static int check_mood(struct osl_row *mood_row, void *data)
177 struct afs_callback_arg *aca = data;
178 char *mood_name, *errmsg;
179 struct osl_object mood_def;
180 struct mood_instance *m;
181 int ret = mood_get_name_and_def_by_row(mood_row, &mood_name, &mood_def);
184 afs_error(aca, "cannot read mood\n");
187 if (!*mood_name) /* ignore dummy row */
189 m = alloc_new_mood("check");
190 ret = mp_init(mood_def.data, mood_def.size, &m->parser_context,
193 afs_error(aca, "%s: %s\n%s\n", mood_name, errmsg,
194 para_strerror(-ret));
198 ret = 1; /* don't fail the loop on invalid mood definitions */
200 osl_close_disk_object(&mood_def);
205 * Check all moods for syntax errors.
207 * \param aca Output goes to ->pbout, errors to ->fd on the error band.
209 * \return Negative on fatal errors. Inconsistent mood definitions are not
210 * considered an error.
212 int mood_check_callback(struct afs_callback_arg *aca)
214 para_printf(&aca->pbout, "checking moods...\n");
215 return osl(osl_rbtree_loop(moods_table, BLOBCOL_ID, aca, check_mood));
219 * The normalized num_played and last_played values are defined as
221 * nn := -(np - mean_n) / sigma_n and nl := -(lp - mean_l) / sigma_l
223 * For a (hypothetical) file with np = 0 and lp = now we thus have
225 * nn = mean_n / sigma_n =: hn > 0
226 * nl = -(now - mean_l) / sigma_l =: hl < 0
228 * We design the score function so that both contributions get the same
229 * weight. Define the np and lp score of an arbitrary file as
231 * sn := nn * -hl and sl := nl * hn
234 * num_played mean/sigma: 87/14
235 * last_played mean/sigma: 45/32 days
237 * We have hn = 87 / 14 = 6.21 and hl = -45 / 32 = -1.41. Multiplying
238 * nn of every file with the correction factor 1.41 and nl with
239 * 6.21 makes the weight of the two contributions equal.
241 * The total score s := sn + sl has the representation
243 * s = -cn * (np - mean_n) - cl * (lp - mean_l)
245 * with positive correction factors
247 * cn = (now - mean_l) / (sqrt(ql) * sqrt(qn) / n)
248 * cl = mean_n / (sqrt(ql) * sqrt(qn) / n)
250 * where ql and qn are the quadratic deviations stored in the statistics
251 * structure and n is the number of admissible files. To avoid integer
252 * overflows and rounding errors we store the common divisor of the
253 * correction factors separately.
255 static int64_t normalized_value(int64_t x, int64_t n, int64_t sum, int64_t qd)
259 return 100 * (n * x - sum) / (int64_t)int_sqrt(n) / (int64_t)int_sqrt(qd);
262 static long compute_score(struct afs_info *afsi,
263 const struct afs_statistics *stats)
265 long score = -normalized_value(afsi->num_played, stats->num,
266 stats->num_played_sum, stats->num_played_qd);
267 score -= normalized_value(afsi->last_played, stats->num,
268 stats->last_played_sum, stats->last_played_qd);
272 static int add_afs_statistics(const struct osl_row *row,
273 struct afs_statistics *stats)
276 struct afs_info afsi;
279 ret = get_afsi_of_row(row, &afsi);
283 x = afsi.last_played;
284 s = stats->last_played_sum;
286 q = (x > s / n)? x - s / n : s / n - x;
287 stats->last_played_qd += q * q * n / (n + 1);
289 stats->last_played_sum += x;
292 s = stats->num_played_sum;
294 q = (x > s / n)? x - s / n : s / n - x;
295 stats->num_played_qd += q * q * n / (n + 1);
297 stats->num_played_sum += x;
302 static int del_afs_statistics(const struct osl_row *row)
304 struct afs_statistics *stats = ¤t_mood->stats;
305 uint64_t n, s, q, a, new_s;
306 struct afs_info afsi;
308 ret = get_afsi_of_row(row, &afsi);
314 memset(stats, 0, sizeof(*stats));
315 stats->normalization_divisor = 1;
319 s = stats->last_played_sum;
320 q = stats->last_played_qd;
321 a = afsi.last_played;
323 stats->last_played_sum = new_s;
324 stats->last_played_qd = q + s * s / n - a * a
325 - new_s * new_s / (n - 1);
327 s = stats->num_played_sum;
328 q = stats->num_played_qd;
331 stats->num_played_sum = new_s;
332 stats->num_played_qd = q + s * s / n - a * a
333 - new_s * new_s / (n - 1);
340 * At mood load time we determine the set of admissible files for the given
341 * mood where each file is identified by a pointer to a row of the audio file
342 * table. In the first pass the pointers are added to a temporary array and
343 * statistics are computed. When all admissible files have been processed in
344 * this way, the score of each admissible file is computed and the (row, score)
345 * pair is added to the score table. This has to be done in a second pass
346 * since the score depends on the statistics. Finally, the array is freed.
348 struct admissible_array {
349 /** Files are admissible wrt. this mood. */
350 struct mood_instance *m;
351 /** The size of the array */
353 /** Pointer to the array of admissible files. */
354 struct osl_row **array;
358 * Check whether the given audio file is admissible. If it is, add it to array
359 * of admissible files.
361 static int add_if_admissible(struct osl_row *aft_row, void *data)
363 struct admissible_array *aa = data;
364 struct afs_statistics *stats = &aa->m->stats;
366 if (!mp_eval_row(aft_row, aa->m->parser_context))
368 if (stats->num >= aa->size) {
371 aa->array = arr_realloc(aa->array, aa->size,
372 sizeof(struct osl_row *));
374 aa->array[stats->num] = aft_row;
375 return add_afs_statistics(aft_row, stats);
379 * Compute the new quadratic deviation in case one element changes.
381 * \param n Number of elements.
382 * \param old_qd The quadratic deviation before the change.
383 * \param old_val The value that was replaced.
384 * \param new_val The replacement value.
385 * \param old_sum The sum of all elements before the update.
387 * \return The new quadratic deviation resulting from replacing old_val
390 * Given n real numbers a_1, ..., a_n, their sum S = a_1 + ... + a_n,
391 * their quadratic deviation
393 * q = (a_1 - S/n)^2 + ... + (a_n - S/n)^2,
395 * and a real number b, the quadratic deviation q' of a_1,...a_{n-1}, b (ie.
396 * the last number a_n was replaced by b) may be computed in O(1) time in terms
397 * of n, q, a_n, b, and S as
399 * q' = q + d * s - (2 * S + d) * d / n
400 * = q + d * (s - 2 * S / n - d /n),
402 * where d = b - a_n, and s = b + a_n.
404 * Example: n = 3, a_1 = 3, a_2 = 5, a_3 = 7, b = 10. Then S = 15, q = 8, d = 3,
407 * q + d * s - (2 * S + d) * d / n = 8 + 51 - 33 = 26,
409 * which equals q' = (3 - 6)^2 + (5 - 6)^2 + (10 - 6)^2.
412 _static_inline_ int64_t update_quadratic_deviation(int64_t n, int64_t old_qd,
413 int64_t old_val, int64_t new_val, int64_t old_sum)
415 int64_t delta = new_val - old_val;
416 int64_t sigma = new_val + old_val;
417 return old_qd + delta * (sigma - 2 * old_sum / n - delta / n);
420 static void update_afs_statistics(struct afs_info *old_afsi,
421 struct afs_info *new_afsi)
423 struct afs_statistics *stats = ¤t_mood->stats;
425 assert(stats->num > 0);
426 stats->last_played_qd = update_quadratic_deviation(stats->num,
427 stats->last_played_qd, old_afsi->last_played,
428 new_afsi->last_played, stats->last_played_sum);
429 stats->last_played_sum += new_afsi->last_played - old_afsi->last_played;
431 stats->num_played_qd = update_quadratic_deviation(stats->num,
432 stats->num_played_qd, old_afsi->num_played,
433 new_afsi->num_played, stats->num_played_sum);
434 stats->num_played_sum += new_afsi->num_played - old_afsi->num_played;
437 static int add_to_score_table(const struct osl_row *aft_row,
438 const struct afs_statistics *stats)
441 struct afs_info afsi;
442 int ret = get_afsi_of_row(aft_row, &afsi);
446 score = compute_score(&afsi, stats);
447 return score_add(aft_row, score);
450 static int delete_from_statistics_and_score_table(const struct osl_row *aft_row)
452 int ret = del_afs_statistics(aft_row);
455 return score_delete(aft_row);
459 * Delete an audio file from the score table and update mood statistics.
461 * \param aft_row Identifies the row to delete.
465 * \sa \ref score_delete().
467 static int mood_delete_audio_file(const struct osl_row *aft_row)
469 if (!row_belongs_to_score_table(aft_row))
471 return delete_from_statistics_and_score_table(aft_row);
475 * Compute the new score of an audio file wrt. the current mood.
477 * \param aft_row Determines the audio file.
478 * \param old_afsi The audio file selector info before updating.
480 * The \a old_afsi argument may be \p NULL which indicates that no changes to
481 * the audio file info were made.
483 * \return Positive on success, negative on errors.
485 static int mood_update_audio_file(const struct osl_row *aft_row,
486 struct afs_info *old_afsi)
490 bool is_admissible, was_admissible;
491 struct afs_info afsi;
494 return 1; /* nothing to do */
495 was_admissible = row_belongs_to_score_table(aft_row);
496 is_admissible = mp_eval_row(aft_row, current_mood->parser_context);
497 if (!was_admissible && !is_admissible)
499 if (was_admissible && !is_admissible)
500 return delete_from_statistics_and_score_table(aft_row);
501 if (!was_admissible && is_admissible) {
502 ret = add_afs_statistics(aft_row, ¤t_mood->stats);
505 return add_to_score_table(aft_row, ¤t_mood->stats);
508 ret = get_afsi_of_row(aft_row, &afsi);
512 update_afs_statistics(old_afsi, &afsi);
513 score = compute_score(&afsi, ¤t_mood->stats);
514 PARA_DEBUG_LOG("score: %li\n", score);
515 percent = (score + 100) / 3;
518 else if (percent < 0)
520 PARA_DEBUG_LOG("moving to %li%%\n", percent);
521 return score_update(aft_row, percent);
524 /* sse: seconds since epoch. */
525 static char *get_statistics(struct mood_instance *m, int64_t sse)
527 unsigned n = m->stats.num;
528 int mean_days, sigma_days;
530 mean_days = (sse - m->stats.last_played_sum / n) / 3600 / 24;
531 sigma_days = int_sqrt(m->stats.last_played_qd / n) / 3600 / 24;
533 "loaded mood %s (%u files)\n"
534 "last_played mean/sigma: %d/%d days\n"
535 "num_played mean/sigma: %" PRId64 "/%" PRIu64 "\n"
537 m->name? m->name : "(dummy)",
539 mean_days, sigma_days,
540 m->stats.num_played_sum / n,
541 int_sqrt(m->stats.num_played_qd / n)
545 /** Free all resources of the current mood, if any. */
546 void mood_unload(void)
548 destroy_mood(current_mood);
552 static void compute_correction_factors(int64_t sse, struct afs_statistics *s)
555 s->normalization_divisor = int_sqrt(s->last_played_qd)
556 * int_sqrt(s->num_played_qd) / s->num / 100;
557 s->num_played_correction = sse - s->last_played_sum / s->num;
558 s->last_played_correction = s->num_played_sum / s->num;
560 if (s->num_played_correction == 0)
561 s->num_played_correction = 1;
562 if (s->normalization_divisor == 0)
563 s->normalization_divisor = 1;
564 if (s->last_played_correction == 0)
565 s->last_played_correction = 1;
569 * Change the current mood.
571 * \param mood_name The name of the mood to load.
572 * \param msg Error message or mood info is returned here.
574 * If \a mood_name is \a NULL, load the dummy mood that accepts every audio file
575 * and uses a scoring method based only on the \a last_played information.
577 * If the message pointer is not NULL, a suitable message is returned there in
578 * all cases. The caller must free this string.
580 * \return The number of admissible files on success, negative on errors. It is
581 * not considered an error if no files are admissible.
583 * \sa struct \ref afs_info::last_played, \ref mp_eval_row().
585 int mood_load(const char *mood_name, char **msg)
588 struct admissible_array aa = {.size = 0};
590 * We can not use the "now" pointer from sched.c here because we are
591 * called before schedule(), which initializes "now".
596 ret = init_mood_parser(mood_name, &aa.m, msg);
599 } else /* load dummy mood */
600 aa.m = alloc_new_mood(NULL);
601 PARA_NOTICE_LOG("computing statistics of admissible files\n");
602 ret = audio_file_loop(&aa, add_if_admissible);
604 if (msg) /* false if we are called via the event handler */
605 *msg = make_message("audio file loop failed\n");
608 clock_get_realtime(&rnow);
609 compute_correction_factors(rnow.tv_sec, &aa.m->stats);
610 if (aa.m->stats.num == 0) {
612 *msg = make_message("no admissible files\n");
616 for (i = 0; i < aa.m->stats.num; i++) {
617 ret = add_to_score_table(aa.array[i], &aa.m->stats);
621 "could not add row to score table\n");
627 *msg = get_statistics(aa.m, rnow.tv_sec);
628 ret = aa.m->stats.num;
639 * Empty the score table and start over.
641 * This function is called on events which render the current list of
642 * admissible files useless, for example if an attribute is removed from the
645 static int reload_current_mood(void)
648 char *mood_name = NULL;
650 assert(current_mood);
652 PARA_NOTICE_LOG("reloading %s\n", current_mood->name?
653 current_mood->name : "(dummy)");
654 if (current_mood->name)
655 mood_name = para_strdup(current_mood->name);
657 ret = mood_load(mood_name, NULL);
663 * Notification callback for the moods table.
665 * \param event Type of the event just occurred.
667 * \param data Its type depends on the event.
669 * This function updates the score table according to the event that has
670 * occurred. Two actions are possible: (a) reload the current mood, or (b)
671 * add/remove/update the row of the score table which corresponds to the audio
672 * file that has been modified or whose afs info has been changed. It depends
673 * on the type of the event which action (if any) is performed.
675 * The callbacks of command handlers such as com_add() or com_touch() which
676 * modify the audio file table call this function. The virtual streaming system
677 * also calls this after it has updated the afs info of the file it is about to
678 * stream (the one with the highest score). If the file stays admissible, its
679 * score is recomputed so that a different file is picked next time.
683 int moods_event_handler(enum afs_events event, __a_unused struct para_buffer *pb,
690 * The three blob events might change the set of admissible files,
691 * so we must reload the score list.
696 if (data == moods_table || data == playlists_table)
697 return 1; /* no reload necessary for these */
698 return reload_current_mood();
699 /* these also require reload of the score table */
701 case ATTRIBUTE_REMOVE:
702 case ATTRIBUTE_RENAME:
703 return reload_current_mood();
704 /* changes to the aft only require to re-examine the audio file */
706 struct afsi_change_event_data *aced = data;
707 return mood_update_audio_file(aced->aft_row, aced->old_afsi);
710 case AUDIO_FILE_RENAME:
712 return mood_update_audio_file(data, NULL);
713 case AUDIO_FILE_REMOVE:
714 return mood_delete_audio_file(data);