mood.c

   1 /*
   2  * Copyright (C) 2007 Andre Noll <maan@tuebingen.mpg.de>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file mood.c Paraslash's mood handling functions. */
   8
   9 #include <regex.h>
  10 #include <osl.h>
  11 #include <lopsub.h>
  12
  13 #include "para.h"
  14 #include "error.h"
  15 #include "string.h"
  16 #include "afh.h"
  17 #include "afs.h"
  18 #include "list.h"
  19 #include "mm.h"
  20 #include "mood.h"
  21
  22 /*
  23  * Mood parser API. It's overkill to have an own header file for
  24  * these declarations as they are only needed in this .c file.
  25  */
  26 struct mp_context;
  27 int mp_init(const char *definition, int nbytes, struct mp_context **result,
  28                  char **errmsg);
  29 bool mp_eval_row(const struct osl_row *aft_row, struct mp_context *ctx);
  30 void mp_shutdown(struct mp_context *ctx);
  31
  32 /**
  33  * Contains statistical data of the currently admissible audio files.
  34  *
  35  * It is used to assign normalized score values to each admissible audio file.
  36  */
  37 struct afs_statistics {
  38         /** Sum of num played over all admissible files. */
  39         int64_t num_played_sum;
  40         /** Sum of last played times over all admissible files. */
  41         int64_t last_played_sum;
  42         /** Quadratic deviation of num played count. */
  43         int64_t num_played_qd;
  44         /** Quadratic deviation of last played time. */
  45         int64_t last_played_qd;
  46         /** Number of admissible files */
  47         unsigned num;
  48 };
  49 static struct afs_statistics statistics;
  50
  51 /**
  52  * Each line of the current mood corresponds to a mood_item.
  53  */
  54 struct mood_item {
  55         /** The method this line is referring to. */
  56         const struct mood_method *method;
  57         /** The data structure computed by the mood parser. */
  58         void *parser_data;
  59         /** The given score value, or zero if none was given. */
  60         int32_t score_arg;
  61         /** Non-zero if random scoring was requested. */
  62         int random_score;
  63         /** Whether the "not" keyword was given in the mood line. */
  64         int logical_not;
  65         /** The position in the list of items. */
  66         struct list_head mood_item_node;
  67 };
  68
  69 /*
  70  * Created from the mood definition by \ref change_current_mood().
  71  *
  72  * When a mood is opened, each line of its definition is investigated, and a
  73  * corresponding mood item is produced. Each mood line starts with accept,
  74  * deny, or score which determines the type of the mood line. For each such
  75  * type a linked list is maintained whose entries are the mood items.
  76  */
  77 struct mood {
  78         /** The name of this mood. */
  79         char *name;
  80         /** The list of mood items of type \p accept. */
  81         struct list_head accept_list;
  82         /** The list of mood items of type \p deny. */
  83         struct list_head deny_list;
  84         /** The list of mood items of type \p score. */
  85         struct list_head score_list;
  86         /* Only used for version 2 moods. */
  87         struct mp_context *parser_context;
  88 };
  89
  90 /*
  91  * If current_mood is NULL then no mood is currently open. If
  92  * current_mood->name is NULL, the dummy mood is currently open.
  93  */
  94 static struct mood *current_mood;
  95
  96 /*
  97  * Find the position of the most-significant set bit.
  98  *
  99  * Copied and slightly adapted from the linux source tree, version 4.9.39
 100  * (2017-07).
 101  */
 102 __a_const static uint32_t fls64(uint64_t v)
 103 {
 104         int n = 63;
 105         const uint64_t ones = ~(uint64_t)0U;
 106
 107         if ((v & (ones << 32)) == 0) {
 108                 n -= 32;
 109                 v <<= 32;
 110         }
 111         if ((v & (ones << (64 - 16))) == 0) {
 112                 n -= 16;
 113                 v <<= 16;
 114         }
 115         if ((v & (ones << (64 - 8))) == 0) {
 116                 n -= 8;
 117                 v <<= 8;
 118         }
 119         if ((v & (ones << (64 - 4))) == 0) {
 120                 n -= 4;
 121                 v <<= 4;
 122         }
 123         if ((v & (ones << (64 - 2))) == 0) {
 124                 n -= 2;
 125                 v <<= 2;
 126         }
 127         if ((v & (ones << (64 - 1))) == 0)
 128                 n -= 1;
 129         return n;
 130 }
 131
 132 /*
 133  * Compute the integer square root floor(sqrt(x)).
 134  *
 135  * Taken 2007 from the linux source tree.
 136  */
 137 __a_const static uint64_t int_sqrt(uint64_t x)
 138 {
 139         uint64_t op = x, res = 0, one = 1;
 140
 141         one = one << (fls64(x) & ~one);
 142         while (one != 0) {
 143                 if (op >= res + one) {
 144                         op = op - (res + one);
 145                         res = res + 2 * one;
 146                 }
 147                 res /= 2;
 148                 one /= 4;
 149         }
 150         return res;
 151 }
 152
 153 /*
 154  * Returns true if row matches, false if it does not match. In any case score
 155  * and score_arg_sum are set/increased accordingly.
 156  */
 157 static bool get_item_score(struct mood_item *item, const struct afs_info *afsi,
 158                 const struct afh_info *afhi, const char *path, long *score,
 159                 long *score_arg_sum)
 160 {
 161         int ret;
 162         bool match = true;
 163
 164         *score_arg_sum += item->random_score? 100 : PARA_ABS(item->score_arg);
 165         ret = 100;
 166         if (item->method) {
 167                 ret = item->method->score_function(path, afsi, afhi,
 168                         item->parser_data);
 169                 if ((ret < 0 && !item->logical_not) || (ret >= 0 && item->logical_not))
 170                         match = false;
 171         }
 172         if (item->random_score)
 173                 *score = PARA_ABS(ret) * para_random(100);
 174         else
 175                 *score = PARA_ABS(ret) * item->score_arg;
 176         return match;
 177 }
 178
 179 /* returns 1 if row admissible, 0 if not, negative on errors */
 180 static int row_is_admissible(const struct osl_row *aft_row, struct mood *m,
 181                 long *scorep)
 182 {
 183         struct mood_item *item;
 184         int ret;
 185         bool match;
 186         long score_arg_sum = 0, score = 0, item_score;
 187         struct afs_info afsi;
 188         struct afh_info afhi;
 189         char *path;
 190
 191         if (!m)
 192                 return -E_NO_MOOD;
 193         if (m->parser_context) {
 194                 *scorep = 0;
 195                 return mp_eval_row(aft_row, m->parser_context);
 196         }
 197         ret = get_afsi_of_row(aft_row, &afsi);
 198         if (ret < 0)
 199                 return ret;
 200         ret = get_afhi_of_row(aft_row, &afhi);
 201         if (ret < 0)
 202                 return ret;
 203         ret = get_audio_file_path_of_row(aft_row, &path);
 204         if (ret < 0)
 205                 return ret;
 206         /* reject audio file if it matches any entry in the deny list */
 207         list_for_each_entry(item, &m->deny_list, mood_item_node) {
 208                 match = get_item_score(item, &afsi, &afhi, path, &item_score,
 209                         &score_arg_sum);
 210                 if (match) /* not admissible */
 211                         return 0;
 212                 score += item_score;
 213         }
 214         match = false;
 215         list_for_each_entry(item, &m->accept_list, mood_item_node) {
 216                 ret = get_item_score(item, &afsi, &afhi, path, &item_score,
 217                         &score_arg_sum);
 218                 if (ret == 0)
 219                         continue;
 220                 match = true;
 221                 score += item_score;
 222         }
 223         /* reject if there is no matching entry in the accept list */
 224         if (!match && !list_empty(&m->accept_list))
 225                 return 0;
 226         list_for_each_entry(item, &m->score_list, mood_item_node) {
 227                 match = get_item_score(item, &afsi, &afhi, path, &item_score,
 228                         &score_arg_sum);
 229                 if (match)
 230                         score += item_score;
 231         }
 232         if (score_arg_sum)
 233                 score /= score_arg_sum;
 234         *scorep = score;
 235         return 1;
 236 }
 237
 238 static void cleanup_list_entry(struct mood_item *item)
 239 {
 240         if (item->method && item->method->cleanup)
 241                 item->method->cleanup(item->parser_data);
 242         else
 243                 free(item->parser_data);
 244         list_del(&item->mood_item_node);
 245         free(item);
 246 }
 247
 248 static void destroy_mood(struct mood *m)
 249 {
 250         struct mood_item *tmp, *item;
 251
 252         if (!m)
 253                 return;
 254         list_for_each_entry_safe(item, tmp, &m->accept_list, mood_item_node)
 255                 cleanup_list_entry(item);
 256         list_for_each_entry_safe(item, tmp, &m->deny_list, mood_item_node)
 257                 cleanup_list_entry(item);
 258         list_for_each_entry_safe(item, tmp, &m->score_list, mood_item_node)
 259                 cleanup_list_entry(item);
 260         free(m->name);
 261         mp_shutdown(m->parser_context);
 262         free(m);
 263 }
 264
 265 static struct mood *alloc_new_mood(const char *name)
 266 {
 267         struct mood *m = para_calloc(sizeof(struct mood));
 268         if (name)
 269                 m->name = para_strdup(name);
 270         INIT_LIST_HEAD(&m->accept_list);
 271         INIT_LIST_HEAD(&m->deny_list);
 272         INIT_LIST_HEAD(&m->score_list);
 273         return m;
 274 }
 275
 276 /** The different types of a mood line. */
 277 enum mood_line_type {
 278         /** Invalid. */
 279         ML_INVALID,
 280         /** Accept line. */
 281         ML_ACCEPT,
 282         /** Deny line. */
 283         ML_DENY,
 284         /** Score line. */
 285         ML_SCORE
 286 };
 287
 288 /** Data passed to the parser of a mood line. */
 289 struct mood_line_parser_data {
 290         /** The mood this mood line belongs to. */
 291         struct mood *m;
 292         /** The line number in the mood definition. */
 293         unsigned line_num;
 294 };
 295
 296 /*
 297  * <accept [with score <score>] | deny [with score <score>]  | score <score>>
 298  *      [if] [not] <mood_method> [options]
 299  * <score> is either an integer or "random" which assigns a random score to
 300  * all matching files
 301  */
 302 static int parse_mood_line(char *mood_line, void *data)
 303 {
 304         struct mood_line_parser_data *mlpd = data;
 305         char **argv;
 306         unsigned num_words;
 307         char **w;
 308         int i, ret;
 309         enum mood_line_type mlt = ML_INVALID;
 310         struct mood_item *mi = NULL;
 311
 312         mlpd->line_num++;
 313         ret = create_argv(mood_line, " \t", &argv);
 314         if (ret < 0)
 315                 return ret;
 316         num_words = ret;
 317         if (!num_words) /* empty line */
 318                 goto out;
 319         w = argv;
 320         if (**w == '#') /* comment */
 321                 goto out;
 322         if (!strcmp(*w, "accept"))
 323                 mlt = ML_ACCEPT;
 324         else if (!strcmp(*w, "deny"))
 325                 mlt = ML_DENY;
 326         else if (!strcmp(*w, "score"))
 327                 mlt = ML_SCORE;
 328         ret = -E_MOOD_SYNTAX;
 329         if (mlt == ML_INVALID)
 330                 goto out;
 331         mi = para_calloc(sizeof(struct mood_item));
 332         if (mlt != ML_SCORE) {
 333                 ret = -E_MOOD_SYNTAX;
 334                 w++;
 335                 if (!*w)
 336                         goto out;
 337                 if (strcmp(*w, "with"))
 338                         goto check_for_if;
 339                 w++;
 340                 if (!*w)
 341                         goto out;
 342                 if (strcmp(*w, "score"))
 343                         goto out;
 344         }
 345         if (mlt == ML_SCORE || !strcmp(*w, "score")) {
 346                 ret = -E_MOOD_SYNTAX;
 347                 w++;
 348                 if (!*w)
 349                         goto out;
 350                 if (strcmp(*w, "random")) {
 351                         mi->random_score = 0;
 352                         ret = para_atoi32(*w, &mi->score_arg);
 353                         if (ret < 0)
 354                                 goto out;
 355                 } else {
 356                         mi->random_score = 1;
 357                         if (!*(w + 1))
 358                         goto success; /* the line "score random" is valid */
 359                 }
 360         } else
 361                 mi->score_arg = 0;
 362         ret = -E_MOOD_SYNTAX;
 363         w++;
 364         if (!*w)
 365                 goto out;
 366 check_for_if:
 367         if (!strcmp(*w, "if")) {
 368                 ret = -E_MOOD_SYNTAX;
 369                 w++;
 370                 if (!*w)
 371                         goto out;
 372         }
 373         if (!strcmp(*w, "not")) {
 374                 ret = -E_MOOD_SYNTAX;
 375                 w++;
 376                 if (!*w)
 377                         goto out;
 378                 mi->logical_not = 1;
 379         } else
 380                 mi->logical_not = 0;
 381         for (i = 0; mood_methods[i].parser; i++) {
 382                 if (strcmp(*w, mood_methods[i].name))
 383                         continue;
 384                 break;
 385         }
 386         ret = -E_MOOD_SYNTAX;
 387         if (!mood_methods[i].parser)
 388                 goto out;
 389         ret = mood_methods[i].parser(num_words - 1 - (w - argv), w,
 390                 &mi->parser_data);
 391         if (ret < 0)
 392                 goto out;
 393         mi->method = &mood_methods[i];
 394 success:
 395         if (mlpd->m) {
 396                 if (mlt == ML_ACCEPT)
 397                         para_list_add(&mi->mood_item_node, &mlpd->m->accept_list);
 398                 else if (mlt == ML_DENY)
 399                         para_list_add(&mi->mood_item_node, &mlpd->m->deny_list);
 400                 else
 401                         para_list_add(&mi->mood_item_node, &mlpd->m->score_list);
 402         }
 403         PARA_DEBUG_LOG("%s entry added, method: %p\n", mlt == ML_ACCEPT? "accept" :
 404                 (mlt == ML_DENY? "deny" : "score"), mi->method);
 405         ret = 1;
 406 out:
 407         free_argv(argv);
 408         if (mi && (ret < 0 || !mlpd->m)) { /* mi was not added to any list */
 409                 free(mi->parser_data);
 410                 free(mi);
 411         }
 412         return ret;
 413 }
 414
 415 static int load_mood(const struct osl_row *mood_row, struct mood **m,
 416                 char **errmsg)
 417 {
 418         char *mood_name;
 419         struct osl_object mood_def;
 420         struct mood_line_parser_data mlpd = {.line_num = 0};
 421         int ret;
 422
 423         *m = NULL;
 424         ret = mood_get_name_and_def_by_row(mood_row, &mood_name, &mood_def);
 425         if (ret < 0)
 426                 return ret;
 427         if (!*mood_name)
 428                 return -E_DUMMY_ROW;
 429         mlpd.m = alloc_new_mood(mood_name);
 430         ret = for_each_line(FELF_READ_ONLY, mood_def.data, mood_def.size,
 431                 parse_mood_line, &mlpd);
 432         if (ret < 0) {
 433                 PARA_INFO_LOG("opening version 2 mood %s\n", mlpd.m->name);
 434                 ret = mp_init(mood_def.data, mood_def.size, &mlpd.m->parser_context,
 435                         errmsg);
 436                 if (ret < 0)
 437                         destroy_mood(mlpd.m);
 438         } else {
 439                 PARA_WARNING_LOG("loaded version 1 mood %s\n", mlpd.m->name);
 440                 PARA_WARNING_LOG("please convert to version 2\n");
 441                 ret = 1;
 442         }
 443         osl_close_disk_object(&mood_def);
 444         if (ret >= 0)
 445                 *m = mlpd.m;
 446         return ret;
 447 }
 448
 449 static int check_mood(struct osl_row *mood_row, void *data)
 450 {
 451         struct para_buffer *pb = data;
 452         char *mood_name;
 453         struct osl_object mood_def;
 454         struct mood_line_parser_data mlpd = {.line_num = 0};
 455
 456         int ret = mood_get_name_and_def_by_row(mood_row, &mood_name, &mood_def);
 457
 458         if (ret < 0) {
 459                 para_printf(pb, "cannot read mood\n");
 460                 return ret;
 461         }
 462         if (!*mood_name) /* ignore dummy row */
 463                 goto out;
 464         ret = for_each_line(FELF_READ_ONLY, mood_def.data, mood_def.size,
 465                 parse_mood_line, &mlpd);
 466         if (ret < 0) {
 467                 char *errmsg;
 468                 struct mood *m = alloc_new_mood("check");
 469                 ret = mp_init(mood_def.data, mood_def.size, &m->parser_context,
 470                         &errmsg);
 471                 if (ret < 0) {
 472                         para_printf(pb, "%s: %s\n", mood_name, errmsg);
 473                         free(errmsg);
 474                         para_printf(pb, "%s\n", para_strerror(-ret));
 475                 } else
 476                         destroy_mood(m);
 477         } else {
 478                 para_printf(pb, "%s: v1 mood, please convert to v2\n",
 479                         mood_name);
 480
 481         }
 482         ret = 1; /* don't fail the loop on invalid mood definitions */
 483 out:
 484         osl_close_disk_object(&mood_def);
 485         return ret;
 486 }
 487
 488 /**
 489  * Check all moods for syntax errors.
 490  *
 491  * \param aca Only ->pbout is used for diagnostics.
 492  *
 493  * \return Negative on fatal errors. Inconsistent mood definitions are not
 494  * considered an error.
 495  */
 496 int mood_check_callback(struct afs_callback_arg *aca)
 497 {
 498         para_printf(&aca->pbout, "checking moods...\n");
 499         return osl(osl_rbtree_loop(moods_table, BLOBCOL_ID, &aca->pbout,
 500                 check_mood));
 501 }
 502
 503 static int64_t normalized_value(int64_t x, int64_t n, int64_t sum, int64_t qd)
 504 {
 505         if (!n || !qd)
 506                 return 0;
 507         return 100 * (n * x - sum) / (int64_t)int_sqrt(n) / (int64_t)int_sqrt(qd);
 508 }
 509
 510 static long compute_score(struct afs_info *afsi, long mood_score)
 511 {
 512         mood_score -= normalized_value(afsi->num_played, statistics.num,
 513                 statistics.num_played_sum, statistics.num_played_qd);
 514         mood_score -= normalized_value(afsi->last_played, statistics.num,
 515                 statistics.last_played_sum, statistics.last_played_qd);
 516         return mood_score / 3;
 517 }
 518
 519 static int add_afs_statistics(const struct osl_row *row)
 520 {
 521         uint64_t n, x, s, q;
 522         struct afs_info afsi;
 523         int ret;
 524
 525         ret = get_afsi_of_row(row, &afsi);
 526         if (ret < 0)
 527                 return ret;
 528         n = statistics.num;
 529         x = afsi.last_played;
 530         s = statistics.last_played_sum;
 531         if (n > 0) {
 532                 q = (x > s / n)? x - s / n : s / n - x;
 533                 statistics.last_played_qd += q * q * n / (n + 1);
 534         }
 535         statistics.last_played_sum += x;
 536
 537         x = afsi.num_played;
 538         s = statistics.num_played_sum;
 539         if (n > 0) {
 540                 q = (x > s / n)? x - s / n : s / n - x;
 541                 statistics.num_played_qd += q * q * n / (n + 1);
 542         }
 543         statistics.num_played_sum += x;
 544         statistics.num++;
 545         return 1;
 546 }
 547
 548 static int del_afs_statistics(const struct osl_row *row)
 549 {
 550         uint64_t n, s, q, a, new_s;
 551         struct afs_info afsi;
 552         int ret;
 553         ret = get_afsi_of_row(row, &afsi);
 554         if (ret < 0)
 555                 return ret;
 556         n = statistics.num;
 557         assert(n);
 558         if (n == 1) {
 559                 memset(&statistics, 0, sizeof(statistics));
 560                 return 1;
 561         }
 562
 563         s = statistics.last_played_sum;
 564         q = statistics.last_played_qd;
 565         a = afsi.last_played;
 566         new_s = s - a;
 567         statistics.last_played_sum = new_s;
 568         statistics.last_played_qd = q + s * s / n - a * a
 569                 - new_s * new_s / (n - 1);
 570
 571         s = statistics.num_played_sum;
 572         q = statistics.num_played_qd;
 573         a = afsi.num_played;
 574         new_s = s - a;
 575         statistics.num_played_sum = new_s;
 576         statistics.num_played_qd = q + s * s / n - a * a
 577                 - new_s * new_s / (n - 1);
 578
 579         statistics.num--;
 580         return 1;
 581 }
 582
 583 /*
 584  * At mood open time we determine the set of admissible files for the given
 585  * mood. The mood score of each admissible file is computed by adding up all
 586  * mood item scores. Next, we update the afs statistics and append a struct
 587  * admissible_file_info to a temporary array.
 588  *
 589  * When all files have been processed in this way, the final score of each
 590  * admissible file is computed by adding the dynamic score (which depends on
 591  * the afs_statistics and the current time) to the mood score. Finally, all
 592  * audio files in the temporary array are added to the score table and the
 593  * array is freed.
 594  */
 595 struct admissible_file_info
 596 {
 597         /** The admissible audio file. */
 598         struct osl_row *aft_row;
 599         /** Its score. */
 600         long score;
 601 };
 602
 603 /** The temporary array of admissible files. */
 604 struct admissible_array {
 605         /** Files are admissible wrt. this mood. */
 606         struct mood *m;
 607         /** The size of the array */
 608         unsigned size;
 609         /** Pointer to the array of admissible files. */
 610         struct admissible_file_info *array;
 611 };
 612
 613 /**
 614  * Add an entry to the array of admissible files.
 615  *
 616  * \param aft_row The audio file to be added.
 617  * \param private_data Pointer to a struct admissible_file_info.
 618  *
 619  * \return 1 if row admissible, 0 if not, negative on errors.
 620  */
 621 static int add_if_admissible(struct osl_row *aft_row, void *data)
 622 {
 623         struct admissible_array *aa = data;
 624         int ret;
 625         long score = 0;
 626
 627         ret = row_is_admissible(aft_row, aa->m, &score);
 628         if (ret <= 0)
 629                 return ret;
 630         if (statistics.num >= aa->size) {
 631                 aa->size *= 2;
 632                 aa->size += 100;
 633                 aa->array = para_realloc(aa->array,
 634                         aa->size * sizeof(struct admissible_file_info));
 635         }
 636         aa->array[statistics.num].aft_row = aft_row;
 637         aa->array[statistics.num].score = score;
 638         ret = add_afs_statistics(aft_row);
 639         if (ret < 0)
 640                 return ret;
 641         return 1;
 642 }
 643
 644 /**
 645  * Compute the new quadratic deviation in case one element changes.
 646  *
 647  * \param n Number of elements.
 648  * \param old_qd The quadratic deviation before the change.
 649  * \param old_val The value that was replaced.
 650  * \param new_val The replacement value.
 651  * \param old_sum The sum of all elements before the update.
 652  *
 653  * \return The new quadratic deviation resulting from replacing old_val
 654  * by new_val.
 655  *
 656  * Given n real numbers a_1, ..., a_n, their sum S = a_1 + ... + a_n,
 657  * their quadratic deviation
 658  *
 659  * q = (a_1 - S/n)^2 + ... + (a_n - S/n)^2,
 660  *
 661  * and a real number b, the quadratic deviation q' of a_1,...a_{n-1}, b (ie.
 662  * the last number a_n was replaced by b) may be computed in O(1) time in terms
 663  * of n, q, a_n, b, and S as
 664  *
 665  *      q' = q + d * s - (2 * S + d) * d / n
 666  *         = q + d * (s - 2 * S / n - d /n),
 667  *
 668  * where d = b - a_n, and s = b + a_n.
 669  *
 670  * Example: n = 3, a_1 = 3, a_2 = 5, a_3 = 7, b = 10. Then S = 15, q = 8, d = 3,
 671  * s = 17, so
 672  *
 673  *      q + d * s - (2 * S + d) * d / n = 8 + 51 - 33 = 26,
 674  *
 675  * which equals q' = (3 - 6)^2 + (5 - 6)^2 + (10 - 6)^2.
 676  *
 677  */
 678 _static_inline_ int64_t update_quadratic_deviation(int64_t n, int64_t old_qd,
 679                 int64_t old_val, int64_t new_val, int64_t old_sum)
 680 {
 681         int64_t delta = new_val - old_val;
 682         int64_t sigma = new_val + old_val;
 683         return old_qd + delta * (sigma - 2 * old_sum / n - delta / n);
 684 }
 685
 686 static int update_afs_statistics(struct afs_info *old_afsi,
 687                 struct afs_info *new_afsi)
 688 {
 689         unsigned n;
 690         int ret = get_num_admissible_files(&n);
 691
 692         if (ret < 0)
 693                 return ret;
 694         assert(n);
 695
 696         statistics.last_played_qd = update_quadratic_deviation(n,
 697                 statistics.last_played_qd, old_afsi->last_played,
 698                 new_afsi->last_played, statistics.last_played_sum);
 699         statistics.last_played_sum += new_afsi->last_played - old_afsi->last_played;
 700
 701         statistics.num_played_qd = update_quadratic_deviation(n,
 702                 statistics.num_played_qd, old_afsi->num_played,
 703                 new_afsi->num_played, statistics.num_played_sum);
 704         statistics.num_played_sum += new_afsi->num_played - old_afsi->num_played;
 705         return 1;
 706 }
 707
 708 static int add_to_score_table(const struct osl_row *aft_row, long mood_score)
 709 {
 710         long score;
 711         struct afs_info afsi;
 712         int ret = get_afsi_of_row(aft_row, &afsi);
 713
 714         if (ret < 0)
 715                 return ret;
 716         score = compute_score(&afsi, mood_score);
 717         return score_add(aft_row, score);
 718 }
 719
 720 static int delete_from_statistics_and_score_table(const struct osl_row *aft_row)
 721 {
 722         int ret = del_afs_statistics(aft_row);
 723         if (ret < 0)
 724                 return ret;
 725         return score_delete(aft_row);
 726 }
 727
 728 /**
 729  * Delete one entry from the statistics and from the score table.
 730  *
 731  * \param aft_row The audio file which is no longer admissible.
 732  *
 733  * \return Positive on success, negative on errors.
 734  *
 735  * \sa \ref score_delete().
 736  */
 737 static int mood_delete_audio_file(const struct osl_row *aft_row)
 738 {
 739         int ret;
 740
 741         ret = row_belongs_to_score_table(aft_row, NULL);
 742         if (ret < 0)
 743                 return ret;
 744         if (!ret) /* not admissible, nothing to do */
 745                 return 1;
 746         return delete_from_statistics_and_score_table(aft_row);
 747 }
 748
 749 /**
 750  * Compute the new score of an audio file wrt. the current mood.
 751  *
 752  * \param aft_row Determines the audio file.
 753  * \param old_afsi The audio file selector info before updating.
 754  *
 755  * The \a old_afsi argument may be \p NULL which indicates that no changes to
 756  * the audio file info were made.
 757  *
 758  * \return Positive on success, negative on errors.
 759  */
 760 static int mood_update_audio_file(const struct osl_row *aft_row,
 761                 struct afs_info *old_afsi)
 762 {
 763         long score, percent;
 764         int ret, is_admissible, was_admissible = 0;
 765         struct afs_info afsi;
 766         unsigned rank;
 767
 768         if (!current_mood)
 769                 return 1; /* nothing to do */
 770         ret = row_belongs_to_score_table(aft_row, &rank);
 771         if (ret < 0)
 772                 return ret;
 773         was_admissible = ret;
 774         ret = row_is_admissible(aft_row, current_mood, &score);
 775         if (ret < 0)
 776                 return ret;
 777         is_admissible = (ret > 0);
 778         if (!was_admissible && !is_admissible)
 779                 return 1;
 780         if (was_admissible && !is_admissible)
 781                 return delete_from_statistics_and_score_table(aft_row);
 782         if (!was_admissible && is_admissible) {
 783                 ret = add_afs_statistics(aft_row);
 784                 if (ret < 0)
 785                         return ret;
 786                 return add_to_score_table(aft_row, score);
 787         }
 788         /* update score */
 789         ret = get_afsi_of_row(aft_row, &afsi);
 790         if (ret < 0)
 791                 return ret;
 792         if (old_afsi) {
 793                 ret = update_afs_statistics(old_afsi, &afsi);
 794                 if (ret < 0)
 795                         return ret;
 796         }
 797         score = compute_score(&afsi, score);
 798         PARA_DEBUG_LOG("score: %li\n", score);
 799         percent = (score + 100) / 3;
 800         if (percent > 100)
 801                 percent = 100;
 802         else if (percent < 0)
 803                 percent = 0;
 804         PARA_DEBUG_LOG("moving from rank %u to %li%%\n", rank, percent);
 805         return score_update(aft_row, percent);
 806 }
 807
 808 static void log_statistics(void)
 809 {
 810         unsigned n = statistics.num;
 811         int mean_days, sigma_days;
 812         /*
 813          * We can not use the "now" pointer from sched.c here because we are
 814          * called before schedule(), which initializes "now".
 815          */
 816         struct timeval rnow;
 817
 818         assert(current_mood);
 819         PARA_NOTICE_LOG("loaded mood %s\n", current_mood->name?
 820                 current_mood->name : "(dummy)");
 821         if (!n) {
 822                 PARA_WARNING_LOG("no admissible files\n");
 823                 return;
 824         }
 825         PARA_NOTICE_LOG("%u admissible files\n", statistics.num);
 826         clock_get_realtime(&rnow);
 827         mean_days = (rnow.tv_sec - statistics.last_played_sum / n) / 3600 / 24;
 828         sigma_days = int_sqrt(statistics.last_played_qd / n) / 3600 / 24;
 829         PARA_NOTICE_LOG("last_played mean/sigma: %d/%d days\n", mean_days, sigma_days);
 830         PARA_NOTICE_LOG("num_played mean/sigma: %llu/%llu\n",
 831                 (long long unsigned)statistics.num_played_sum / n,
 832                 (long long unsigned)int_sqrt(statistics.num_played_qd / n));
 833 }
 834
 835 /**
 836  * Close the current mood.
 837  *
 838  * Frees all resources of the current mood.
 839  */
 840 void close_current_mood(void)
 841 {
 842         destroy_mood(current_mood);
 843         current_mood = NULL;
 844         memset(&statistics, 0, sizeof(statistics));
 845 }
 846
 847 /**
 848  * Change the current mood.
 849  *
 850  * \param mood_name The name of the mood to open.
 851  * \param errmsg Error description is returned here.
 852  *
 853  * If \a mood_name is \a NULL, load the dummy mood that accepts every audio file
 854  * and uses a scoring method based only on the \a last_played information.
 855  *
 856  * The errmsg pointer may be NULL, in which case no error message will be
 857  * returned. If a non-NULL pointer is given, the caller must free *errmsg.
 858  *
 859  * If there is already an open mood, it will be closed first.
 860  *
 861  * \return Positive on success, negative on errors. Loading the dummy mood
 862  * always succeeds.
 863  *
 864  * \sa struct \ref afs_info::last_played, \ref mp_eval_row().
 865  */
 866 int change_current_mood(const char *mood_name, char **errmsg)
 867 {
 868         int i, ret;
 869         struct admissible_array aa = {
 870                 .size = 0,
 871                 .array = NULL
 872         };
 873
 874         if (mood_name) {
 875                 struct mood *m;
 876                 struct osl_row *row;
 877                 struct osl_object obj = {
 878                         .data = (char *)mood_name,
 879                         .size = strlen(mood_name) + 1
 880                 };
 881                 ret = osl(osl_get_row(moods_table, BLOBCOL_NAME, &obj, &row));
 882                 if (ret < 0) {
 883                         PARA_NOTICE_LOG("no such mood: %s\n", mood_name);
 884                         return ret;
 885                 }
 886                 ret = load_mood(row, &m, errmsg);
 887                 if (ret < 0)
 888                         return ret;
 889                 close_current_mood();
 890                 current_mood = m;
 891         } else { /* load dummy mood */
 892                 close_current_mood();
 893                 current_mood = alloc_new_mood(NULL);
 894         }
 895         aa.m = current_mood;
 896         PARA_NOTICE_LOG("computing statistics of admissible files\n");
 897         ret = audio_file_loop(&aa, add_if_admissible);
 898         if (ret < 0)
 899                 return ret;
 900         for (i = 0; i < statistics.num; i++) {
 901                 struct admissible_file_info *a = aa.array + i;
 902                 ret = add_to_score_table(a->aft_row, a->score);
 903                 if (ret < 0)
 904                         goto out;
 905         }
 906         log_statistics();
 907         ret = statistics.num;
 908 out:
 909         free(aa.array);
 910         return ret;
 911 }
 912
 913 /*
 914  * Close and re-open the current mood.
 915  *
 916  * This function is called on events which render the current list of
 917  * admissible files useless, for example if an attribute is removed from the
 918  * attribute table.
 919  *
 920  * If no mood is currently open, the function returns success.
 921  */
 922 static int reload_current_mood(void)
 923 {
 924         int ret;
 925         char *mood_name = NULL;
 926
 927         ret = clear_score_table();
 928         if (ret < 0)
 929                 return ret;
 930         if (!current_mood)
 931                 return 1;
 932         PARA_NOTICE_LOG("reloading %s\n", current_mood->name?
 933                 current_mood->name : "(dummy)");
 934         if (current_mood->name)
 935                 mood_name = para_strdup(current_mood->name);
 936         close_current_mood();
 937         ret = change_current_mood(mood_name, NULL);
 938         free(mood_name);
 939         return ret;
 940 }
 941
 942 /**
 943  * Notification callback for the moods table.
 944  *
 945  * \param event Type of the event just occurred.
 946  * \param pb Unused.
 947  * \param data Its type depends on the event.
 948  *
 949  * This function performs actions required due to the occurrence of the given
 950  * event. Possible actions include reload of the current mood and update of the
 951  * score of an audio file.
 952  *
 953  * \return Standard.
 954  */
 955 int moods_event_handler(enum afs_events event, __a_unused struct para_buffer *pb,
 956                 void *data)
 957 {
 958         if (!current_mood)
 959                 return 0;
 960         switch (event) {
 961         /*
 962          * The three blob events might change the set of admissible files,
 963          * so we must reload the score list.
 964          */
 965         case BLOB_RENAME:
 966         case BLOB_REMOVE:
 967         case BLOB_ADD:
 968                 if (data == moods_table || data == playlists_table)
 969                         return 1; /* no reload necessary for these */
 970                 return reload_current_mood();
 971         /* these also require reload of the score table */
 972         case ATTRIBUTE_ADD:
 973         case ATTRIBUTE_REMOVE:
 974         case ATTRIBUTE_RENAME:
 975                 return reload_current_mood();
 976         /* changes to the aft only require to re-examine the audio file */
 977         case AFSI_CHANGE: {
 978                 struct afsi_change_event_data *aced = data;
 979                 return mood_update_audio_file(aced->aft_row, aced->old_afsi);
 980                 }
 981         case AFHI_CHANGE:
 982         case AUDIO_FILE_RENAME:
 983         case AUDIO_FILE_ADD:
 984                 return mood_update_audio_file(data, NULL);
 985         case AUDIO_FILE_REMOVE:
 986                 return mood_delete_audio_file(data);
 987         default:
 988                 return 1;
 989         }
 990 }