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);
141 static struct mood_instance *alloc_new_mood(const char *name)
143 struct mood_instance *m = zalloc(sizeof(*m));
146 m->name = para_strdup(name);
147 m->stats.normalization_divisor = 1;
151 static int init_mood_parser(const char *mood_name, struct mood_instance **m,
154 struct osl_object mood_def;
159 *err = make_message("empty mood name\n");
160 return -ERRNO_TO_PARA_ERROR(EINVAL);
162 ret = mood_get_def_by_name(mood_name, &mood_def);
165 *err = make_message("could not read mood definition\n");
168 *m = alloc_new_mood(mood_name);
169 PARA_INFO_LOG("loading mood %s\n", mood_name);
170 ret = mp_init(mood_def.data, mood_def.size, &(*m)->parser_context, err);
171 osl_close_disk_object(&mood_def);
177 static int check_mood(struct osl_row *mood_row, void *data)
179 struct afs_callback_arg *aca = data;
180 char *mood_name, *errmsg;
181 struct osl_object mood_def;
182 struct mood_instance *m;
183 int ret = mood_get_name_and_def_by_row(mood_row, &mood_name, &mood_def);
186 afs_error(aca, "cannot read mood\n");
189 if (!*mood_name) /* ignore dummy row */
191 m = alloc_new_mood("check");
192 ret = mp_init(mood_def.data, mood_def.size, &m->parser_context,
195 afs_error(aca, "%s: %s\n%s\n", mood_name, errmsg,
196 para_strerror(-ret));
200 ret = 1; /* don't fail the loop on invalid mood definitions */
202 osl_close_disk_object(&mood_def);
207 * Check all moods for syntax errors.
209 * \param aca Output goes to ->pbout, errors to ->fd on the error band.
211 * \return Negative on fatal errors. Inconsistent mood definitions are not
212 * considered an error.
214 int mood_check_callback(struct afs_callback_arg *aca)
216 para_printf(&aca->pbout, "checking moods...\n");
217 return osl(osl_rbtree_loop(moods_table, BLOBCOL_ID, aca, check_mood));
221 * The normalized num_played and last_played values are defined as
223 * nn := -(np - mean_n) / sigma_n and nl := -(lp - mean_l) / sigma_l
225 * For a (hypothetical) file with np = 0 and lp = now we thus have
227 * nn = mean_n / sigma_n =: hn > 0
228 * nl = -(now - mean_l) / sigma_l =: hl < 0
230 * We design the score function so that both contributions get the same
231 * weight. Define the np and lp score of an arbitrary file as
233 * sn := nn * -hl and sl := nl * hn
236 * num_played mean/sigma: 87/14
237 * last_played mean/sigma: 45/32 days
239 * We have hn = 87 / 14 = 6.21 and hl = -45 / 32 = -1.41. Multiplying
240 * nn of every file with the correction factor 1.41 and nl with
241 * 6.21 makes the weight of the two contributions equal.
243 * The total score s := sn + sl has the representation
245 * s = -cn * (np - mean_n) - cl * (lp - mean_l)
247 * with positive correction factors
249 * cn = (now - mean_l) / (sqrt(ql) * sqrt(qn) / n)
250 * cl = mean_n / (sqrt(ql) * sqrt(qn) / n)
252 * where ql and qn are the quadratic deviations stored in the statistics
253 * structure and n is the number of admissible files. To avoid integer
254 * overflows and rounding errors we store the common divisor of the
255 * correction factors separately.
257 static long compute_score(struct afs_info *afsi,
258 const struct afs_statistics *stats)
260 int64_t mean_n, mean_l,score_n, score_l;
262 assert(stats->normalization_divisor > 0);
263 assert(stats->num > 0);
264 mean_n = stats->num_played_sum / stats->num;
265 mean_l = stats->last_played_sum / stats->num;
267 score_n = -((int64_t)afsi->num_played - mean_n)
268 * stats->num_played_correction
269 / stats->normalization_divisor;
270 score_l = -((int64_t)afsi->last_played - mean_l)
271 * stats->last_played_correction
272 / stats->normalization_divisor;
273 return (score_n + score_l) / 2;
276 static int add_afs_statistics(const struct osl_row *row,
277 struct afs_statistics *stats)
280 struct afs_info afsi;
283 ret = get_afsi_of_row(row, &afsi);
287 x = afsi.last_played;
288 s = stats->last_played_sum;
290 q = (x > s / n)? x - s / n : s / n - x;
291 stats->last_played_qd += q * q * n / (n + 1);
293 stats->last_played_sum += x;
296 s = stats->num_played_sum;
298 q = (x > s / n)? x - s / n : s / n - x;
299 stats->num_played_qd += q * q * n / (n + 1);
301 stats->num_played_sum += x;
306 static int del_afs_statistics(const struct osl_row *row)
308 struct afs_statistics *stats = ¤t_mood->stats;
309 uint64_t n, s, q, a, new_s;
310 struct afs_info afsi;
312 ret = get_afsi_of_row(row, &afsi);
318 memset(stats, 0, sizeof(*stats));
319 stats->normalization_divisor = 1;
323 s = stats->last_played_sum;
324 q = stats->last_played_qd;
325 a = afsi.last_played;
327 stats->last_played_sum = new_s;
328 stats->last_played_qd = q + s * s / n - a * a
329 - new_s * new_s / (n - 1);
331 s = stats->num_played_sum;
332 q = stats->num_played_qd;
335 stats->num_played_sum = new_s;
336 stats->num_played_qd = q + s * s / n - a * a
337 - new_s * new_s / (n - 1);
344 * At mood load time we determine the set of admissible files for the given
345 * mood where each file is identified by a pointer to a row of the audio file
346 * table. In the first pass the pointers are added to a temporary array and
347 * statistics are computed. When all admissible files have been processed in
348 * this way, the score of each admissible file is computed and the (row, score)
349 * pair is added to the score table. This has to be done in a second pass
350 * since the score depends on the statistics. Finally, the array is freed.
352 struct admissible_array {
353 /** Files are admissible wrt. this mood. */
354 struct mood_instance *m;
355 /** The size of the array */
357 /** Pointer to the array of admissible files. */
358 struct osl_row **array;
362 * Check whether the given audio file is admissible. If it is, add it to array
363 * of admissible files.
365 static int add_if_admissible(struct osl_row *aft_row, void *data)
367 struct admissible_array *aa = data;
368 struct afs_statistics *stats = &aa->m->stats;
370 if (!mp_eval_row(aft_row, aa->m->parser_context))
372 if (stats->num >= aa->size) {
375 aa->array = arr_realloc(aa->array, aa->size,
376 sizeof(struct osl_row *));
378 aa->array[stats->num] = aft_row;
379 return add_afs_statistics(aft_row, stats);
383 * Compute the new quadratic deviation in case one element changes.
385 * \param n Number of elements.
386 * \param old_qd The quadratic deviation before the change.
387 * \param old_val The value that was replaced.
388 * \param new_val The replacement value.
389 * \param old_sum The sum of all elements before the update.
391 * \return The new quadratic deviation resulting from replacing old_val
394 * Given n real numbers a_1, ..., a_n, their sum S = a_1 + ... + a_n,
395 * their quadratic deviation
397 * q = (a_1 - S/n)^2 + ... + (a_n - S/n)^2,
399 * and a real number b, the quadratic deviation q' of a_1,...a_{n-1}, b (ie.
400 * the last number a_n was replaced by b) may be computed in O(1) time in terms
401 * of n, q, a_n, b, and S as
403 * q' = q + d * s - (2 * S + d) * d / n
404 * = q + d * (s - 2 * S / n - d /n),
406 * where d = b - a_n, and s = b + a_n.
408 * Example: n = 3, a_1 = 3, a_2 = 5, a_3 = 7, b = 10. Then S = 15, q = 8, d = 3,
411 * q + d * s - (2 * S + d) * d / n = 8 + 51 - 33 = 26,
413 * which equals q' = (3 - 6)^2 + (5 - 6)^2 + (10 - 6)^2.
416 _static_inline_ int64_t update_quadratic_deviation(int64_t n, int64_t old_qd,
417 int64_t old_val, int64_t new_val, int64_t old_sum)
419 int64_t delta = new_val - old_val;
420 int64_t sigma = new_val + old_val;
421 return old_qd + delta * (sigma - 2 * old_sum / n - delta / n);
424 static void update_afs_statistics(struct afs_info *old_afsi,
425 struct afs_info *new_afsi)
427 struct afs_statistics *stats = ¤t_mood->stats;
429 assert(stats->num > 0);
430 stats->last_played_qd = update_quadratic_deviation(stats->num,
431 stats->last_played_qd, old_afsi->last_played,
432 new_afsi->last_played, stats->last_played_sum);
433 stats->last_played_sum += new_afsi->last_played - old_afsi->last_played;
435 stats->num_played_qd = update_quadratic_deviation(stats->num,
436 stats->num_played_qd, old_afsi->num_played,
437 new_afsi->num_played, stats->num_played_sum);
438 stats->num_played_sum += new_afsi->num_played - old_afsi->num_played;
441 static int add_to_score_table(const struct osl_row *aft_row,
442 struct mood_instance *m)
445 struct afs_info afsi;
446 int ret = get_afsi_of_row(aft_row, &afsi);
450 score = compute_score(&afsi, &m->stats);
451 return score_add(aft_row, score, m->score_table);
454 static int delete_from_statistics_and_score_table(const struct osl_row *aft_row)
456 int ret = del_afs_statistics(aft_row);
459 return score_delete(aft_row);
463 * Delete an audio file from the score table and update mood statistics.
465 * \param aft_row Identifies the row to delete.
469 * \sa \ref score_delete().
471 static int mood_delete_audio_file(const struct osl_row *aft_row)
473 if (!row_belongs_to_score_table(aft_row))
475 return delete_from_statistics_and_score_table(aft_row);
479 * Compute the new score of an audio file wrt. the current mood.
481 * \param aft_row Determines the audio file.
482 * \param old_afsi The audio file selector info before updating.
484 * The \a old_afsi argument may be \p NULL which indicates that no changes to
485 * the audio file info were made.
487 * \return Positive on success, negative on errors.
489 static int mood_update_audio_file(const struct osl_row *aft_row,
490 struct afs_info *old_afsi)
494 bool is_admissible, was_admissible;
495 struct afs_info afsi;
498 return 1; /* nothing to do */
499 was_admissible = row_belongs_to_score_table(aft_row);
500 is_admissible = mp_eval_row(aft_row, current_mood->parser_context);
501 if (!was_admissible && !is_admissible)
503 if (was_admissible && !is_admissible)
504 return delete_from_statistics_and_score_table(aft_row);
505 if (!was_admissible && is_admissible) {
506 ret = add_afs_statistics(aft_row, ¤t_mood->stats);
509 return add_to_score_table(aft_row, current_mood);
512 ret = get_afsi_of_row(aft_row, &afsi);
516 update_afs_statistics(old_afsi, &afsi);
517 score = compute_score(&afsi, ¤t_mood->stats);
518 PARA_DEBUG_LOG("score: %li\n", score);
519 percent = (score + 100) / 3;
522 else if (percent < 0)
524 PARA_DEBUG_LOG("moving to %li%%\n", percent);
525 return score_update(aft_row, percent);
528 /* sse: seconds since epoch. */
529 static char *get_statistics(struct mood_instance *m, int64_t sse)
531 unsigned n = m->stats.num;
532 int mean_days, sigma_days;
534 mean_days = (sse - m->stats.last_played_sum / n) / 3600 / 24;
535 sigma_days = int_sqrt(m->stats.last_played_qd / n) / 3600 / 24;
537 "loaded mood %s (%u files)\n"
538 "last_played mean/sigma: %d/%d days\n"
539 "num_played mean/sigma: %" PRId64 "/%" PRIu64 "\n"
541 m->name? m->name : "(dummy)",
543 mean_days, sigma_days,
544 m->stats.num_played_sum / n,
545 int_sqrt(m->stats.num_played_qd / n)
550 * Free all resources of a mood instance.
552 * \param m As obtained by \ref mood_load(). If NULL, unload the current mood.
554 * It's OK to call this with m == NULL even if no current mood is loaded.
556 void mood_unload(struct mood_instance *m)
559 return destroy_mood(m);
560 destroy_mood(current_mood);
564 static void compute_correction_factors(int64_t sse, struct afs_statistics *s)
567 s->normalization_divisor = int_sqrt(s->last_played_qd)
568 * int_sqrt(s->num_played_qd) / s->num / 100;
569 s->num_played_correction = sse - s->last_played_sum / s->num;
570 s->last_played_correction = s->num_played_sum / s->num;
572 if (s->num_played_correction == 0)
573 s->num_played_correction = 1;
574 if (s->normalization_divisor == 0)
575 s->normalization_divisor = 1;
576 if (s->last_played_correction == 0)
577 s->last_played_correction = 1;
581 * Populate a score table with admissible files for the given mood.
583 * This consults the mood table to initialize the mood parser with the mood
584 * expression stored in the blob object which corresponds to the given name. A
585 * score table is allocated and populated with references to those entries of
586 * the audio file table which evaluate as admissible with respect to the mood
587 * expression. For each audio file a score value is computed and stored along
588 * with the file reference.
590 * \param mood_name The name of the mood to load.
591 * \param result Opaque, refers to the mood parser and the score table.
592 * \param msg Error message or mood info is returned here.
594 * If the mood name is NULL, the dummy mood is loaded. This mood regards every
595 * audio file as admissible.
597 * A NULL result pointer instructs the function to operate on the current mood.
598 * That is, on the mood instance which is used by the server to select the next
599 * audio file for streaming. In this mode of operation, the mood which was
600 * active before the call, if any, is unloaded on success.
602 * If result is not NULL, the current mood is unaffected and *result points to
603 * an initialized mood instance on success. The caller can pass this reference
604 * to \ref mood_loop() to iterate over the admissible files, and should call
605 * \ref mood_unload() to free the mood instance afterwards.
607 * If the message pointer is not NULL, a suitable message is returned there in
608 * all cases. The caller must free this string.
610 * \return The number of admissible files on success, negative on errors. On
611 * errors, the current mood remains unaffected even if result is NULL. It is
612 * not considered an error if no files are admissible.
614 * \sa \ref mp_eval_row().
616 int mood_load(const char *mood_name, struct mood_instance **result, char **msg)
619 struct admissible_array aa = {.size = 0};
621 * We can not use the "now" pointer from sched.c here because we are
622 * called before schedule(), which initializes "now".
627 ret = init_mood_parser(mood_name, &aa.m, msg);
630 } else /* load dummy mood */
631 aa.m = alloc_new_mood(NULL);
632 PARA_NOTICE_LOG("computing statistics of admissible files\n");
633 ret = audio_file_loop(&aa, add_if_admissible);
635 if (msg) /* false if we are called via the event handler */
636 *msg = make_message("audio file loop failed\n");
639 clock_get_realtime(&rnow);
640 compute_correction_factors(rnow.tv_sec, &aa.m->stats);
641 if (aa.m->stats.num == 0) {
643 *msg = make_message("no admissible files\n");
648 score_open(&aa.m->score_table);
649 for (i = 0; i < aa.m->stats.num; i++) {
650 ret = add_to_score_table(aa.array[i], aa.m);
654 "could not add row to score table\n");
660 *msg = get_statistics(aa.m, rnow.tv_sec);
661 ret = aa.m->stats.num;
676 * Iterate over the admissible files of a mood instance.
678 * This wrapper around \ref score_loop() is the mood counterpart of \ref
681 * \param m Determines the score table to iterate. Must not be NULL.
682 * \param func See \ref score_loop().
683 * \param data See \ref score_loop().
685 * \return See \ref score_loop(), \ref playlist_loop().
687 int mood_loop(struct mood_instance *m, osl_rbtree_loop_func *func, void *data)
689 return score_loop(func, m->score_table, data);
693 * Empty the score table and start over.
695 * This function is called on events which render the current set of admissible
696 * files invalid, for example if an attribute is removed from the attribute
699 static int reload_current_mood(void)
702 char *mood_name = NULL;
704 assert(current_mood);
706 PARA_NOTICE_LOG("reloading %s\n", current_mood->name?
707 current_mood->name : "(dummy)");
708 if (current_mood->name)
709 mood_name = para_strdup(current_mood->name);
711 ret = mood_load(mood_name, NULL, NULL);
717 * Notification callback for the moods table.
719 * \param event Type of the event just occurred.
721 * \param data Its type depends on the event.
723 * This function updates the score table according to the event that has
724 * occurred. Two actions are possible: (a) reload the current mood, or (b)
725 * add/remove/update the row of the score table which corresponds to the audio
726 * file that has been modified or whose afs info has been changed. It depends
727 * on the type of the event which action (if any) is performed.
729 * The callbacks of command handlers such as com_add() or com_touch() which
730 * modify the audio file table call this function. The virtual streaming system
731 * also calls this after it has updated the afs info of the file it is about to
732 * stream (the one with the highest score). If the file stays admissible, its
733 * score is recomputed so that a different file is picked next time.
737 int moods_event_handler(enum afs_events event, __a_unused struct para_buffer *pb,
744 * The three blob events might change the set of admissible files,
745 * so we must reload the score list.
750 if (data == moods_table || data == playlists_table)
751 return 1; /* no reload necessary for these */
752 return reload_current_mood();
753 /* these also require reload of the score table */
755 case ATTRIBUTE_REMOVE:
756 case ATTRIBUTE_RENAME:
757 return reload_current_mood();
758 /* changes to the aft only require to re-examine the audio file */
760 struct afsi_change_event_data *aced = data;
761 return mood_update_audio_file(aced->aft_row, aced->old_afsi);
764 case AUDIO_FILE_RENAME:
766 return mood_update_audio_file(data, NULL);
767 case AUDIO_FILE_REMOVE:
768 return mood_delete_audio_file(data);