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;
62 /** NULL means to operate on the global score table. */
63 struct osl_table *score_table;
67 * If current_mood is NULL then no mood is currently loaded. If
68 * current_mood->name is NULL, the current mood is the dummy mood.
70 * The statistics are adjusted dynamically through this pointer as files are
71 * added, removed or played.
73 static struct mood_instance *current_mood;
76 * Find the position of the most-significant set bit.
78 * Copied and slightly adapted from the linux source tree, version 4.9.39
81 __a_const static uint32_t fls64(uint64_t v)
84 const uint64_t ones = ~(uint64_t)0U;
86 if ((v & (ones << 32)) == 0) {
90 if ((v & (ones << (64 - 16))) == 0) {
94 if ((v & (ones << (64 - 8))) == 0) {
98 if ((v & (ones << (64 - 4))) == 0) {
102 if ((v & (ones << (64 - 2))) == 0) {
106 if ((v & (ones << (64 - 1))) == 0)
112 * Compute the integer square root floor(sqrt(x)).
114 * Taken 2007 from the linux source tree.
116 __a_const static uint64_t int_sqrt(uint64_t x)
118 uint64_t op = x, res = 0, one = 1;
120 one = one << (fls64(x) & ~one);
122 if (op >= res + one) {
123 op = op - (res + one);
132 static void destroy_mood(struct mood_instance *m)
136 mp_shutdown(m->parser_context);
138 score_close(m->score_table);
143 static struct mood_instance *alloc_new_mood(const char *name)
145 struct mood_instance *m = zalloc(sizeof(*m));
148 m->name = para_strdup(name);
149 m->stats.normalization_divisor = 1;
153 static int init_mood_parser(const char *mood_name, struct mood_instance **m,
156 struct osl_object mood_def;
161 *err = make_message("empty mood name\n");
162 return -ERRNO_TO_PARA_ERROR(EINVAL);
164 ret = mood_get_def_by_name(mood_name, &mood_def);
167 *err = make_message("could not read mood definition\n");
170 *m = alloc_new_mood(mood_name);
171 PARA_INFO_LOG("loading mood %s\n", mood_name);
172 ret = mp_init(mood_def.data, mood_def.size, &(*m)->parser_context, err);
173 osl_close_disk_object(&mood_def);
179 static int check_mood(struct osl_row *mood_row, void *data)
181 struct afs_callback_arg *aca = data;
182 char *mood_name, *errmsg;
183 struct osl_object mood_def;
184 struct mood_instance *m;
185 int ret = mood_get_name_and_def_by_row(mood_row, &mood_name, &mood_def);
188 afs_error(aca, "cannot read mood\n");
191 if (!*mood_name) /* ignore dummy row */
193 m = alloc_new_mood("check");
194 ret = mp_init(mood_def.data, mood_def.size, &m->parser_context,
197 afs_error(aca, "%s: %s\n%s\n", mood_name, errmsg,
198 para_strerror(-ret));
202 ret = 1; /* don't fail the loop on invalid mood definitions */
204 osl_close_disk_object(&mood_def);
209 * Check all moods for syntax errors.
211 * \param aca Output goes to ->pbout, errors to ->fd on the error band.
213 * \return Negative on fatal errors. Inconsistent mood definitions are not
214 * considered an error.
216 int mood_check_callback(struct afs_callback_arg *aca)
218 para_printf(&aca->pbout, "checking moods...\n");
219 return osl(osl_rbtree_loop(moods_table, BLOBCOL_ID, aca, check_mood));
223 * The normalized num_played and last_played values are defined as
225 * nn := -(np - mean_n) / sigma_n and nl := -(lp - mean_l) / sigma_l
227 * For a (hypothetical) file with np = 0 and lp = now we thus have
229 * nn = mean_n / sigma_n =: hn > 0
230 * nl = -(now - mean_l) / sigma_l =: hl < 0
232 * We design the score function so that both contributions get the same
233 * weight. Define the np and lp score of an arbitrary file as
235 * sn := nn * -hl and sl := nl * hn
238 * num_played mean/sigma: 87/14
239 * last_played mean/sigma: 45/32 days
241 * We have hn = 87 / 14 = 6.21 and hl = -45 / 32 = -1.41. Multiplying
242 * nn of every file with the correction factor 1.41 and nl with
243 * 6.21 makes the weight of the two contributions equal.
245 * The total score s := sn + sl has the representation
247 * s = -cn * (np - mean_n) - cl * (lp - mean_l)
249 * with positive correction factors
251 * cn = (now - mean_l) / (sqrt(ql) * sqrt(qn) / n)
252 * cl = mean_n / (sqrt(ql) * sqrt(qn) / n)
254 * where ql and qn are the quadratic deviations stored in the statistics
255 * structure and n is the number of admissible files. To avoid integer
256 * overflows and rounding errors we store the common divisor of the
257 * correction factors separately.
259 static long compute_score(struct afs_info *afsi,
260 const struct afs_statistics *stats)
262 int64_t mean_n, mean_l,score_n, score_l;
264 assert(stats->normalization_divisor > 0);
265 assert(stats->num > 0);
266 mean_n = stats->num_played_sum / stats->num;
267 mean_l = stats->last_played_sum / stats->num;
269 score_n = -((int64_t)afsi->num_played - mean_n)
270 * stats->num_played_correction
271 / stats->normalization_divisor;
272 score_l = -((int64_t)afsi->last_played - mean_l)
273 * stats->last_played_correction
274 / stats->normalization_divisor;
275 return (score_n + score_l) / 2;
278 static int add_afs_statistics(const struct osl_row *row,
279 struct afs_statistics *stats)
282 struct afs_info afsi;
285 ret = get_afsi_of_row(row, &afsi);
289 x = afsi.last_played;
290 s = stats->last_played_sum;
292 q = (x > s / n)? x - s / n : s / n - x;
293 stats->last_played_qd += q * q * n / (n + 1);
295 stats->last_played_sum += x;
298 s = stats->num_played_sum;
300 q = (x > s / n)? x - s / n : s / n - x;
301 stats->num_played_qd += q * q * n / (n + 1);
303 stats->num_played_sum += x;
308 static int del_afs_statistics(const struct osl_row *row)
310 struct afs_statistics *stats = ¤t_mood->stats;
311 uint64_t n, s, q, a, new_s;
312 struct afs_info afsi;
314 ret = get_afsi_of_row(row, &afsi);
320 memset(stats, 0, sizeof(*stats));
321 stats->normalization_divisor = 1;
325 s = stats->last_played_sum;
326 q = stats->last_played_qd;
327 a = afsi.last_played;
329 stats->last_played_sum = new_s;
330 stats->last_played_qd = q + s * s / n - a * a
331 - new_s * new_s / (n - 1);
333 s = stats->num_played_sum;
334 q = stats->num_played_qd;
337 stats->num_played_sum = new_s;
338 stats->num_played_qd = q + s * s / n - a * a
339 - new_s * new_s / (n - 1);
346 * At mood load time we determine the set of admissible files for the given
347 * mood where each file is identified by a pointer to a row of the audio file
348 * table. In the first pass the pointers are added to a temporary array and
349 * statistics are computed. When all admissible files have been processed in
350 * this way, the score of each admissible file is computed and the (row, score)
351 * pair is added to the score table. This has to be done in a second pass
352 * since the score depends on the statistics. Finally, the array is freed.
354 struct admissible_array {
355 /** Files are admissible wrt. this mood. */
356 struct mood_instance *m;
357 /** The size of the array */
359 /** Pointer to the array of admissible files. */
360 struct osl_row **array;
364 * Check whether the given audio file is admissible. If it is, add it to array
365 * of admissible files.
367 static int add_if_admissible(struct osl_row *aft_row, void *data)
369 struct admissible_array *aa = data;
370 struct afs_statistics *stats = &aa->m->stats;
372 if (!mp_eval_row(aft_row, aa->m->parser_context))
374 if (stats->num >= aa->size) {
377 aa->array = arr_realloc(aa->array, aa->size,
378 sizeof(struct osl_row *));
380 aa->array[stats->num] = aft_row;
381 return add_afs_statistics(aft_row, stats);
385 * Compute the new quadratic deviation in case one element changes.
387 * \param n Number of elements.
388 * \param old_qd The quadratic deviation before the change.
389 * \param old_val The value that was replaced.
390 * \param new_val The replacement value.
391 * \param old_sum The sum of all elements before the update.
393 * \return The new quadratic deviation resulting from replacing old_val
396 * Given n real numbers a_1, ..., a_n, their sum S = a_1 + ... + a_n,
397 * their quadratic deviation
399 * q = (a_1 - S/n)^2 + ... + (a_n - S/n)^2,
401 * and a real number b, the quadratic deviation q' of a_1,...a_{n-1}, b (ie.
402 * the last number a_n was replaced by b) may be computed in O(1) time in terms
403 * of n, q, a_n, b, and S as
405 * q' = q + d * s - (2 * S + d) * d / n
406 * = q + d * (s - 2 * S / n - d /n),
408 * where d = b - a_n, and s = b + a_n.
410 * Example: n = 3, a_1 = 3, a_2 = 5, a_3 = 7, b = 10. Then S = 15, q = 8, d = 3,
413 * q + d * s - (2 * S + d) * d / n = 8 + 51 - 33 = 26,
415 * which equals q' = (3 - 6)^2 + (5 - 6)^2 + (10 - 6)^2.
418 _static_inline_ int64_t update_quadratic_deviation(int64_t n, int64_t old_qd,
419 int64_t old_val, int64_t new_val, int64_t old_sum)
421 int64_t delta = new_val - old_val;
422 int64_t sigma = new_val + old_val;
423 return old_qd + delta * (sigma - 2 * old_sum / n - delta / n);
426 static void update_afs_statistics(struct afs_info *old_afsi,
427 struct afs_info *new_afsi)
429 struct afs_statistics *stats = ¤t_mood->stats;
431 assert(stats->num > 0);
432 stats->last_played_qd = update_quadratic_deviation(stats->num,
433 stats->last_played_qd, old_afsi->last_played,
434 new_afsi->last_played, stats->last_played_sum);
435 stats->last_played_sum += new_afsi->last_played - old_afsi->last_played;
437 stats->num_played_qd = update_quadratic_deviation(stats->num,
438 stats->num_played_qd, old_afsi->num_played,
439 new_afsi->num_played, stats->num_played_sum);
440 stats->num_played_sum += new_afsi->num_played - old_afsi->num_played;
443 static int add_to_score_table(const struct osl_row *aft_row,
444 struct mood_instance *m)
447 struct afs_info afsi;
448 int ret = get_afsi_of_row(aft_row, &afsi);
452 score = compute_score(&afsi, &m->stats);
453 return score_add(aft_row, score, m->score_table);
456 static int delete_from_statistics_and_score_table(const struct osl_row *aft_row)
458 int ret = del_afs_statistics(aft_row);
461 return score_delete(aft_row);
465 * Delete an audio file from the score table and update mood statistics.
467 * \param aft_row Identifies the row to delete.
471 * \sa \ref score_delete().
473 static int mood_delete_audio_file(const struct osl_row *aft_row)
475 if (!row_belongs_to_score_table(aft_row))
477 return delete_from_statistics_and_score_table(aft_row);
481 * Compute the new score of an audio file wrt. the current mood.
483 * \param aft_row Determines the audio file.
484 * \param old_afsi The audio file selector info before updating.
486 * The \a old_afsi argument may be \p NULL which indicates that no changes to
487 * the audio file info were made.
489 * \return Positive on success, negative on errors.
491 static int mood_update_audio_file(const struct osl_row *aft_row,
492 struct afs_info *old_afsi)
496 bool is_admissible, was_admissible;
497 struct afs_info afsi;
500 return 1; /* nothing to do */
501 was_admissible = row_belongs_to_score_table(aft_row);
502 is_admissible = mp_eval_row(aft_row, current_mood->parser_context);
503 if (!was_admissible && !is_admissible)
505 if (was_admissible && !is_admissible)
506 return delete_from_statistics_and_score_table(aft_row);
507 if (!was_admissible && is_admissible) {
508 ret = add_afs_statistics(aft_row, ¤t_mood->stats);
511 return add_to_score_table(aft_row, current_mood);
514 ret = get_afsi_of_row(aft_row, &afsi);
518 update_afs_statistics(old_afsi, &afsi);
519 score = compute_score(&afsi, ¤t_mood->stats);
520 PARA_DEBUG_LOG("score: %li\n", score);
521 percent = (score + 100) / 3;
524 else if (percent < 0)
526 PARA_DEBUG_LOG("moving to %li%%\n", percent);
527 return score_update(aft_row, percent);
530 /* sse: seconds since epoch. */
531 static char *get_statistics(struct mood_instance *m, int64_t sse)
533 unsigned n = m->stats.num;
534 int mean_days, sigma_days;
537 return make_message("no admissible files\n");
538 mean_days = (sse - m->stats.last_played_sum / n) / 3600 / 24;
539 sigma_days = int_sqrt(m->stats.last_played_qd / n) / 3600 / 24;
541 "loaded mood %s (%u files)\n"
542 "last_played mean/sigma: %d/%d days\n"
543 "num_played mean/sigma: %" PRId64 "/%" PRIu64 "\n"
544 "correction factor ratio: %.2lf\n"
546 m->name? m->name : "(dummy)",
548 mean_days, sigma_days,
549 m->stats.num_played_sum / n,
550 int_sqrt(m->stats.num_played_qd / n),
551 86400.0 * m->stats.last_played_correction /
552 m->stats.num_played_correction
557 * Free all resources of a mood instance.
559 * \param m As obtained by \ref mood_load(). If NULL, unload the current mood.
561 * It's OK to call this with m == NULL even if no current mood is loaded.
563 void mood_unload(struct mood_instance *m)
566 return destroy_mood(m);
567 destroy_mood(current_mood);
571 static void compute_correction_factors(int64_t sse, struct afs_statistics *s)
574 s->normalization_divisor = int_sqrt(s->last_played_qd)
575 * int_sqrt(s->num_played_qd) / s->num / 100;
576 s->num_played_correction = sse - s->last_played_sum / s->num;
577 s->last_played_correction = s->num_played_sum / s->num;
579 if (s->num_played_correction == 0)
580 s->num_played_correction = 1;
581 if (s->normalization_divisor == 0)
582 s->normalization_divisor = 1;
583 if (s->last_played_correction == 0)
584 s->last_played_correction = 1;
588 * Populate a score table with admissible files for the given mood.
590 * This consults the mood table to initialize the mood parser with the mood
591 * expression stored in the blob object which corresponds to the given name. A
592 * score table is allocated and populated with references to those entries of
593 * the audio file table which evaluate as admissible with respect to the mood
594 * expression. For each audio file a score value is computed and stored along
595 * with the file reference.
597 * \param mood_name The name of the mood to load.
598 * \param result Opaque, refers to the mood parser and the score table.
599 * \param msg Error message or mood info is returned here.
601 * If the mood name is NULL, the dummy mood is loaded. This mood regards every
602 * audio file as admissible.
604 * A NULL result pointer instructs the function to operate on the current mood.
605 * That is, on the mood instance which is used by the server to select the next
606 * audio file for streaming. In this mode of operation, the mood which was
607 * active before the call, if any, is unloaded on success.
609 * If result is not NULL, the current mood is unaffected and *result points to
610 * an initialized mood instance on success. The caller can pass this reference
611 * to \ref mood_loop() to iterate over the admissible files, and should call
612 * \ref mood_unload() to free the mood instance afterwards.
614 * If the message pointer is not NULL, a suitable message is returned there in
615 * all cases. The caller must free this string.
617 * \return The number of admissible files on success, negative on errors. On
618 * errors, the current mood remains unaffected even if result is NULL. It is
619 * not considered an error if no files are admissible.
621 * \sa \ref mp_eval_row().
623 int mood_load(const char *mood_name, struct mood_instance **result, char **msg)
626 struct admissible_array aa = {.size = 0};
628 * We can not use the "now" pointer from sched.c here because we are
629 * called before schedule(), which initializes "now".
634 ret = init_mood_parser(mood_name, &aa.m, msg);
637 } else /* load dummy mood */
638 aa.m = alloc_new_mood(NULL);
639 PARA_NOTICE_LOG("computing statistics of admissible files\n");
640 ret = audio_file_loop(&aa, add_if_admissible);
642 if (msg) /* false if we are called via the event handler */
643 *msg = make_message("audio file loop failed\n");
646 clock_get_realtime(&rnow);
647 compute_correction_factors(rnow.tv_sec, &aa.m->stats);
649 score_open(&aa.m->score_table);
650 for (i = 0; i < aa.m->stats.num; i++) {
651 ret = add_to_score_table(aa.array[i], aa.m);
655 "could not add row to score table\n");
661 *msg = get_statistics(aa.m, rnow.tv_sec);
662 ret = aa.m->stats.num;
672 if (ret <= 0) /* error, or no admissible files */
678 * Iterate over the admissible files of a mood instance.
680 * This wrapper around \ref score_loop() is the mood counterpart of \ref
683 * \param m Determines the score table to iterate. Must not be NULL.
684 * \param func See \ref score_loop().
685 * \param data See \ref score_loop().
687 * \return See \ref score_loop(), \ref playlist_loop().
689 int mood_loop(struct mood_instance *m, osl_rbtree_loop_func *func, void *data)
691 return score_loop(func, m->score_table, data);
695 * Empty the score table and start over.
697 * This function is called on events which render the current set of admissible
698 * files invalid, for example if an attribute is removed from the attribute
701 static int reload_current_mood(void)
704 char *mood_name = NULL;
706 assert(current_mood);
708 PARA_NOTICE_LOG("reloading %s\n", current_mood->name?
709 current_mood->name : "(dummy)");
710 if (current_mood->name)
711 mood_name = para_strdup(current_mood->name);
713 ret = mood_load(mood_name, NULL, NULL);
719 * Notification callback for the moods table.
721 * \param event Type of the event just occurred.
723 * \param data Its type depends on the event.
725 * This function updates the score table according to the event that has
726 * occurred. Two actions are possible: (a) reload the current mood, or (b)
727 * add/remove/update the row of the score table which corresponds to the audio
728 * file that has been modified or whose afs info has been changed. It depends
729 * on the type of the event which action (if any) is performed.
731 * The callbacks of command handlers such as com_add() or com_touch() which
732 * modify the audio file table call this function. The virtual streaming system
733 * also calls this after it has updated the afs info of the file it is about to
734 * stream (the one with the highest score). If the file stays admissible, its
735 * score is recomputed so that a different file is picked next time.
739 int moods_event_handler(enum afs_events event, __a_unused struct para_buffer *pb,
746 * The three blob events might change the set of admissible files,
747 * so we must reload the score list.
752 if (data == moods_table || data == playlists_table)
753 return 1; /* no reload necessary for these */
754 return reload_current_mood();
755 /* these also require reload of the score table */
757 case ATTRIBUTE_REMOVE:
758 case ATTRIBUTE_RENAME:
759 return reload_current_mood();
760 /* changes to the aft only require to re-examine the audio file */
762 struct afsi_change_event_data *aced = data;
763 return mood_update_audio_file(aced->aft_row, aced->old_afsi);
766 case AUDIO_FILE_RENAME:
768 return mood_update_audio_file(data, NULL);
769 case AUDIO_FILE_REMOVE:
770 return mood_delete_audio_file(data);