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 an open mood (parser and statistics).
53 * A structure of this type is allocated and initialized at mood open time.
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 open. If
66 * current_mood->name is NULL, the dummy mood is currently open.
68 * The statistics are adjusted dynamically through this pointer as files are
69 * added, removed or played.
71 static struct mood *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 *m)
134 mp_shutdown(m->parser_context);
139 static struct mood *alloc_new_mood(const char *name)
141 struct mood *m = zalloc(sizeof(struct mood));
143 m->name = para_strdup(name);
144 m->stats.normalization_divisor = 1;
148 static int init_mood_parser(const char *mood_name, struct mood **m, char **err)
150 struct osl_object mood_def;
155 *err = make_message("empty mood name\n");
156 return -ERRNO_TO_PARA_ERROR(EINVAL);
158 ret = mood_get_def_by_name(mood_name, &mood_def);
161 *err = make_message("could not read mood definition\n");
164 *m = alloc_new_mood(mood_name);
165 PARA_INFO_LOG("opening mood %s\n", mood_name);
166 ret = mp_init(mood_def.data, mood_def.size, &(*m)->parser_context, err);
167 osl_close_disk_object(&mood_def);
173 static int check_mood(struct osl_row *mood_row, void *data)
175 struct para_buffer *pb = data;
176 char *mood_name, *errmsg;
177 struct osl_object mood_def;
179 int ret = mood_get_name_and_def_by_row(mood_row, &mood_name, &mood_def);
182 para_printf(pb, "cannot read mood\n");
185 if (!*mood_name) /* ignore dummy row */
187 m = alloc_new_mood("check");
188 ret = mp_init(mood_def.data, mood_def.size, &m->parser_context,
191 para_printf(pb, "%s: %s\n", mood_name, errmsg);
193 para_printf(pb, "%s\n", para_strerror(-ret));
196 ret = 1; /* don't fail the loop on invalid mood definitions */
198 osl_close_disk_object(&mood_def);
203 * Check all moods for syntax errors.
205 * \param aca Only ->pbout is used for diagnostics.
207 * \return Negative on fatal errors. Inconsistent mood definitions are not
208 * considered an error.
210 int mood_check_callback(struct afs_callback_arg *aca)
212 para_printf(&aca->pbout, "checking moods...\n");
213 return osl(osl_rbtree_loop(moods_table, BLOBCOL_ID, &aca->pbout,
218 * The normalized num_played and last_played values are defined as
220 * nn := -(np - mean_n) / sigma_n and nl := -(lp - mean_l) / sigma_l
222 * For a (hypothetical) file with np = 0 and lp = now we thus have
224 * nn = mean_n / sigma_n =: hn > 0
225 * nl = -(now - mean_l) / sigma_l =: hl < 0
227 * We design the score function so that both contributions get the same
228 * weight. Define the np and lp score of an arbitrary file as
230 * sn := nn * -hl and sl := nl * hn
233 * num_played mean/sigma: 87/14
234 * last_played mean/sigma: 45/32 days
236 * We have hn = 87 / 14 = 6.21 and hl = -45 / 32 = -1.41. Multiplying
237 * nn of every file with the correction factor 1.41 and nl with
238 * 6.21 makes the weight of the two contributions equal.
240 * The total score s := sn + sl has the representation
242 * s = -cn * (np - mean_n) - cl * (lp - mean_l)
244 * with positive correction factors
246 * cn = (now - mean_l) / (sqrt(ql) * sqrt(qn) / n)
247 * cl = mean_n / (sqrt(ql) * sqrt(qn) / n)
249 * where ql and qn are the quadratic deviations stored in the statistics
250 * structure and n is the number of admissible files. To avoid integer
251 * overflows and rounding errors we store the common divisor of the
252 * correction factors separately.
254 static int64_t normalized_value(int64_t x, int64_t n, int64_t sum, int64_t qd)
258 return 100 * (n * x - sum) / (int64_t)int_sqrt(n) / (int64_t)int_sqrt(qd);
261 static long compute_score(struct afs_info *afsi,
262 const struct afs_statistics *stats)
264 long score = -normalized_value(afsi->num_played, stats->num,
265 stats->num_played_sum, stats->num_played_qd);
266 score -= normalized_value(afsi->last_played, stats->num,
267 stats->last_played_sum, stats->last_played_qd);
271 static int add_afs_statistics(const struct osl_row *row,
272 struct afs_statistics *stats)
275 struct afs_info afsi;
278 ret = get_afsi_of_row(row, &afsi);
282 x = afsi.last_played;
283 s = stats->last_played_sum;
285 q = (x > s / n)? x - s / n : s / n - x;
286 stats->last_played_qd += q * q * n / (n + 1);
288 stats->last_played_sum += x;
291 s = stats->num_played_sum;
293 q = (x > s / n)? x - s / n : s / n - x;
294 stats->num_played_qd += q * q * n / (n + 1);
296 stats->num_played_sum += x;
301 static int del_afs_statistics(const struct osl_row *row)
303 struct afs_statistics *stats = ¤t_mood->stats;
304 uint64_t n, s, q, a, new_s;
305 struct afs_info afsi;
307 ret = get_afsi_of_row(row, &afsi);
313 memset(stats, 0, sizeof(*stats));
314 stats->normalization_divisor = 1;
318 s = stats->last_played_sum;
319 q = stats->last_played_qd;
320 a = afsi.last_played;
322 stats->last_played_sum = new_s;
323 stats->last_played_qd = q + s * s / n - a * a
324 - new_s * new_s / (n - 1);
326 s = stats->num_played_sum;
327 q = stats->num_played_qd;
330 stats->num_played_sum = new_s;
331 stats->num_played_qd = q + s * s / n - a * a
332 - new_s * new_s / (n - 1);
339 * At mood open time we determine the set of admissible files for the given
340 * mood where each file is identified by a pointer to a row of the audio file
341 * table. In the first pass the pointers are added to a temporary array and
342 * statistics are computed. When all admissible files have been processed in
343 * this way, the score of each admissible file is computed and the (row, score)
344 * pair is added to the score table. This has to be done in a second pass
345 * since the score depends on the statistics. Finally, the array is freed.
347 struct admissible_array {
348 /** Files are admissible wrt. this mood. */
350 /** The size of the array */
352 /** Pointer to the array of admissible files. */
353 struct osl_row **array;
357 * Check whether the given audio file is admissible. If it is, add it to array
358 * of admissible files.
360 static int add_if_admissible(struct osl_row *aft_row, void *data)
362 struct admissible_array *aa = data;
363 struct afs_statistics *stats = &aa->m->stats;
365 if (!mp_eval_row(aft_row, aa->m->parser_context))
367 if (stats->num >= aa->size) {
370 aa->array = arr_realloc(aa->array, aa->size,
371 sizeof(struct osl_row *));
373 aa->array[stats->num] = aft_row;
374 return add_afs_statistics(aft_row, stats);
378 * Compute the new quadratic deviation in case one element changes.
380 * \param n Number of elements.
381 * \param old_qd The quadratic deviation before the change.
382 * \param old_val The value that was replaced.
383 * \param new_val The replacement value.
384 * \param old_sum The sum of all elements before the update.
386 * \return The new quadratic deviation resulting from replacing old_val
389 * Given n real numbers a_1, ..., a_n, their sum S = a_1 + ... + a_n,
390 * their quadratic deviation
392 * q = (a_1 - S/n)^2 + ... + (a_n - S/n)^2,
394 * and a real number b, the quadratic deviation q' of a_1,...a_{n-1}, b (ie.
395 * the last number a_n was replaced by b) may be computed in O(1) time in terms
396 * of n, q, a_n, b, and S as
398 * q' = q + d * s - (2 * S + d) * d / n
399 * = q + d * (s - 2 * S / n - d /n),
401 * where d = b - a_n, and s = b + a_n.
403 * Example: n = 3, a_1 = 3, a_2 = 5, a_3 = 7, b = 10. Then S = 15, q = 8, d = 3,
406 * q + d * s - (2 * S + d) * d / n = 8 + 51 - 33 = 26,
408 * which equals q' = (3 - 6)^2 + (5 - 6)^2 + (10 - 6)^2.
411 _static_inline_ int64_t update_quadratic_deviation(int64_t n, int64_t old_qd,
412 int64_t old_val, int64_t new_val, int64_t old_sum)
414 int64_t delta = new_val - old_val;
415 int64_t sigma = new_val + old_val;
416 return old_qd + delta * (sigma - 2 * old_sum / n - delta / n);
419 static void update_afs_statistics(struct afs_info *old_afsi,
420 struct afs_info *new_afsi)
422 struct afs_statistics *stats = ¤t_mood->stats;
424 assert(stats->num > 0);
425 stats->last_played_qd = update_quadratic_deviation(stats->num,
426 stats->last_played_qd, old_afsi->last_played,
427 new_afsi->last_played, stats->last_played_sum);
428 stats->last_played_sum += new_afsi->last_played - old_afsi->last_played;
430 stats->num_played_qd = update_quadratic_deviation(stats->num,
431 stats->num_played_qd, old_afsi->num_played,
432 new_afsi->num_played, stats->num_played_sum);
433 stats->num_played_sum += new_afsi->num_played - old_afsi->num_played;
436 static int add_to_score_table(const struct osl_row *aft_row,
437 const struct afs_statistics *stats)
440 struct afs_info afsi;
441 int ret = get_afsi_of_row(aft_row, &afsi);
445 score = compute_score(&afsi, stats);
446 return score_add(aft_row, score);
449 static int delete_from_statistics_and_score_table(const struct osl_row *aft_row)
451 int ret = del_afs_statistics(aft_row);
454 return score_delete(aft_row);
458 * Delete an audio file from the score table and update mood statistics.
460 * \param aft_row Identifies the row to delete.
464 * \sa \ref score_delete().
466 static int mood_delete_audio_file(const struct osl_row *aft_row)
468 if (!row_belongs_to_score_table(aft_row))
470 return delete_from_statistics_and_score_table(aft_row);
474 * Compute the new score of an audio file wrt. the current mood.
476 * \param aft_row Determines the audio file.
477 * \param old_afsi The audio file selector info before updating.
479 * The \a old_afsi argument may be \p NULL which indicates that no changes to
480 * the audio file info were made.
482 * \return Positive on success, negative on errors.
484 static int mood_update_audio_file(const struct osl_row *aft_row,
485 struct afs_info *old_afsi)
489 bool is_admissible, was_admissible;
490 struct afs_info afsi;
493 return 1; /* nothing to do */
494 was_admissible = row_belongs_to_score_table(aft_row);
495 is_admissible = mp_eval_row(aft_row, current_mood->parser_context);
496 if (!was_admissible && !is_admissible)
498 if (was_admissible && !is_admissible)
499 return delete_from_statistics_and_score_table(aft_row);
500 if (!was_admissible && is_admissible) {
501 ret = add_afs_statistics(aft_row, ¤t_mood->stats);
504 return add_to_score_table(aft_row, ¤t_mood->stats);
507 ret = get_afsi_of_row(aft_row, &afsi);
511 update_afs_statistics(old_afsi, &afsi);
512 score = compute_score(&afsi, ¤t_mood->stats);
513 PARA_DEBUG_LOG("score: %li\n", score);
514 percent = (score + 100) / 3;
517 else if (percent < 0)
519 PARA_DEBUG_LOG("moving to %li%%\n", percent);
520 return score_update(aft_row, percent);
523 /* sse: seconds since epoch. */
524 static char *get_statistics(struct mood *m, int64_t sse)
526 unsigned n = m->stats.num;
527 int mean_days, sigma_days;
529 mean_days = (sse - m->stats.last_played_sum / n) / 3600 / 24;
530 sigma_days = int_sqrt(m->stats.last_played_qd / n) / 3600 / 24;
532 "loaded mood %s (%u files)\n"
533 "last_played mean/sigma: %d/%d days\n"
534 "num_played mean/sigma: %" PRId64 "/%" PRIu64 "\n"
536 m->name? m->name : "(dummy)",
538 mean_days, sigma_days,
539 m->stats.num_played_sum / n,
540 int_sqrt(m->stats.num_played_qd / n)
545 * Close the current mood.
547 * Frees all resources of the current mood.
549 void close_current_mood(void)
551 destroy_mood(current_mood);
555 static void compute_correction_factors(int64_t sse, struct afs_statistics *s)
558 s->normalization_divisor = int_sqrt(s->last_played_qd)
559 * int_sqrt(s->num_played_qd) / s->num / 100;
560 s->num_played_correction = sse - s->last_played_sum / s->num;
561 s->last_played_correction = s->num_played_sum / s->num;
563 if (s->num_played_correction == 0)
564 s->num_played_correction = 1;
565 if (s->normalization_divisor == 0)
566 s->normalization_divisor = 1;
567 if (s->last_played_correction == 0)
568 s->last_played_correction = 1;
572 * Change the current mood.
574 * If there is already an open mood, it will be closed first.
576 * \param mood_name The name of the mood to open.
577 * \param msg Error message or mood info is returned here.
579 * If \a mood_name is \a NULL, load the dummy mood that accepts every audio file
580 * and uses a scoring method based only on the \a last_played information.
582 * If the message pointer is not NULL, a suitable message is returned there in
583 * all cases. The caller must free this string.
585 * \return The number of admissible files on success, negative on errors. It is
586 * not considered an error if no files are admissible.
588 * \sa struct \ref afs_info::last_played, \ref mp_eval_row().
590 int mood_switch(const char *mood_name, char **msg)
593 struct admissible_array aa = {.size = 0};
595 * We can not use the "now" pointer from sched.c here because we are
596 * called before schedule(), which initializes "now".
601 ret = init_mood_parser(mood_name, &aa.m, msg);
604 } else /* load dummy mood */
605 aa.m = alloc_new_mood(NULL);
606 PARA_NOTICE_LOG("computing statistics of admissible files\n");
607 ret = audio_file_loop(&aa, add_if_admissible);
609 if (msg) /* false if we are called via the event handler */
610 *msg = make_message("audio file loop failed\n");
613 clock_get_realtime(&rnow);
614 compute_correction_factors(rnow.tv_sec, &aa.m->stats);
615 if (aa.m->stats.num == 0) {
617 *msg = make_message("no admissible files\n");
621 for (i = 0; i < aa.m->stats.num; i++) {
622 ret = add_to_score_table(aa.array[i], &aa.m->stats);
626 "could not add row to score table\n");
632 *msg = get_statistics(aa.m, rnow.tv_sec);
633 ret = aa.m->stats.num;
634 close_current_mood();
644 * Close and re-open the current mood.
646 * This function is called on events which render the current list of
647 * admissible files useless, for example if an attribute is removed from the
650 static int reload_current_mood(void)
653 char *mood_name = NULL;
655 assert(current_mood);
656 ret = clear_score_table();
659 PARA_NOTICE_LOG("reloading %s\n", current_mood->name?
660 current_mood->name : "(dummy)");
661 if (current_mood->name)
662 mood_name = para_strdup(current_mood->name);
663 close_current_mood();
664 ret = mood_switch(mood_name, NULL);
670 * Notification callback for the moods table.
672 * \param event Type of the event just occurred.
674 * \param data Its type depends on the event.
676 * This function updates the score table according to the event that has
677 * occurred. Two actions are possible: (a) reload the current mood, or (b)
678 * add/remove/update the row of the score table which corresponds to the audio
679 * file that has been modified or whose afs info has been changed. It depends
680 * on the type of the event which action (if any) is performed.
682 * The callbacks of command handlers such as com_add() or com_touch() which
683 * modify the audio file table call this function. The virtual streaming system
684 * also calls this after it has updated the afs info of the file it is about to
685 * stream (the one with the highest score). If the file stays admissible, its
686 * score is recomputed so that a different file is picked next time.
690 int moods_event_handler(enum afs_events event, __a_unused struct para_buffer *pb,
697 * The three blob events might change the set of admissible files,
698 * so we must reload the score list.
703 if (data == moods_table || data == playlists_table)
704 return 1; /* no reload necessary for these */
705 return reload_current_mood();
706 /* these also require reload of the score table */
708 case ATTRIBUTE_REMOVE:
709 case ATTRIBUTE_RENAME:
710 return reload_current_mood();
711 /* changes to the aft only require to re-examine the audio file */
713 struct afsi_change_event_data *aced = data;
714 return mood_update_audio_file(aced->aft_row, aced->old_afsi);
717 case AUDIO_FILE_RENAME:
719 return mood_update_audio_file(data, NULL);
720 case AUDIO_FILE_REMOVE:
721 return mood_delete_audio_file(data);