score.c

   1 /*
   2  * Copyright (C) 2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file score.c Scoring functions to determine the audio file streaming order. */
   8 #include "para.h"
   9 #include "error.h"
  10 #include "string.h"
  11 #include "afh.h"
  12 #include "afs.h"
  13 #include "list.h"
  14
  15 static struct osl_table *score_table;
  16
  17 static int ptr_compare(const struct osl_object *obj1, const struct osl_object *obj2)
  18 {
  19         void *d1 = *(void **)obj1->data;
  20         void *d2 = *(void **)obj2->data;
  21         return NUM_COMPARE(d1, d2);
  22 }
  23
  24 /**
  25  * Compare the score of two audio files
  26  *
  27  * \param obj1 Pointer to the first score object.
  28  * \param obj2 Pointer to the second score object.
  29  *
  30  * This function first compares the score values as usual integers. If they compare as
  31  * equal, the address of \a obj1 and \a obj2 are compared. So this compare function
  32  * returns zero if and only if \a obj1 and \a obj2 point to the same memory area.
  33  *
  34  * \sa osl_compare_function.
  35  */
  36 static int score_compare(const struct osl_object *obj1, const struct osl_object *obj2)
  37 {
  38         int d1 = *(int*)obj1->data;
  39         int d2 = *(int*)obj2->data;
  40         int ret = NUM_COMPARE(d2, d1);
  41
  42         if (ret)
  43                 return ret;
  44         return NUM_COMPARE(obj2->data, obj1->data);
  45 }
  46
  47 /**
  48  * The score table consists of two columns: The \a aft_row column contains
  49  * pointers to the rows of the audio file table,  and the score column contains
  50  * the current score of the audio file associated with that row.
  51  */
  52 enum score_table_columns {
  53         /** The row of the audio file. */
  54         SCORECOL_AFT_ROW,
  55         /** The score */
  56         SCORECOL_SCORE,
  57         /** This table has two columns */
  58         NUM_SCORE_COLUMNS
  59 };
  60
  61 static struct osl_column_description score_cols[] = {
  62         [SCORECOL_AFT_ROW] = {
  63                 .storage_type = OSL_NO_STORAGE,
  64                 .storage_flags = OSL_RBTREE | OSL_FIXED_SIZE | OSL_UNIQUE | OSL_DONT_FREE,
  65                 .name = "aft_row",
  66                 .compare_function = ptr_compare,
  67                 .data_size = sizeof(void *)
  68         },
  69         [SCORECOL_SCORE] = {
  70                 .storage_type = OSL_NO_STORAGE,
  71                 .storage_flags = OSL_RBTREE | OSL_FIXED_SIZE,
  72                 .name = "score",
  73                 .compare_function = score_compare,
  74                 .data_size = sizeof(long)
  75         }
  76 };
  77
  78 static struct osl_table_description score_table_desc = {
  79         .name = "score",
  80         .num_columns = NUM_SCORE_COLUMNS,
  81         .flags = 0,
  82         .column_descriptions = score_cols
  83 };
  84
  85 /**
  86  * Compute the number of files in score table.
  87  *
  88  * \param num Result is returned here.
  89  *
  90  * \return Positive on success, negative on errors.
  91  *
  92  * \sa osl_get_num_rows().
  93  */
  94 int get_num_admissible_files(unsigned *num)
  95 {
  96         return osl_get_num_rows(score_table, num);
  97 }
  98
  99 /**
 100  * Get the score of the audio file associated with given row of the score table.
 101  *
 102  * \param score_row Pointer to the row in the score table.
 103  * \param score Result is returned here on success.
 104  *
 105  * On errors (negative return value) the content of \a score is undefined.
 106  *
 107  * \return The return value of the underlying call to osl_get_object().
 108  */
 109 static int get_score_of_row(void *score_row, long *score)
 110 {
 111         struct osl_object obj;
 112         int ret = osl_get_object(score_table, score_row, SCORECOL_SCORE, &obj);
 113
 114         if (ret >= 0)
 115                 *score = *(long *)obj.data;
 116         return ret;
 117 }
 118
 119 /**
 120  * Add an entry to the table of admissible files.
 121  *
 122  * \param aft_row The audio file to be added.
 123  * \param score The score for this file.
 124  *
 125  * \return The return value of the underlying call to osl_add_row().
 126  */
 127 int score_add(const struct osl_row *aft_row, long score)
 128 {
 129         int ret;
 130         struct osl_object score_objs[NUM_SCORE_COLUMNS];
 131         size_t size;
 132
 133         assert(aft_row);
 134         size = score_table_desc.column_descriptions[SCORECOL_AFT_ROW].data_size;
 135         score_objs[SCORECOL_AFT_ROW].data = (struct osl_row *)aft_row;
 136         score_objs[SCORECOL_AFT_ROW].size = size;
 137
 138         size = score_table_desc.column_descriptions[SCORECOL_SCORE].data_size;
 139         score_objs[SCORECOL_SCORE].data = para_malloc(size);
 140         score_objs[SCORECOL_SCORE].size = size;
 141         *(int *)(score_objs[SCORECOL_SCORE].data) = score;
 142
 143 //      PARA_DEBUG_LOG("adding %p\n", *(void **) (score_objs[SCORECOL_AFT_ROW].data));
 144         ret = osl_add_row(score_table, score_objs);
 145         if (ret < 0) {
 146                 PARA_ERROR_LOG("%s\n", PARA_STRERROR(-ret));
 147                 free(score_objs[SCORECOL_SCORE].data);
 148         }
 149         return ret;
 150 }
 151
 152 static int get_nth_score(unsigned n, long *score)
 153 {
 154         struct osl_row *row;
 155         int ret = osl_get_nth_row(score_table, SCORECOL_SCORE, n, &row);
 156
 157         if (ret < 0)
 158                 return ret;
 159         return get_score_of_row(row, score);
 160 }
 161
 162 /**
 163  * Replace a row of the score table.
 164  *
 165  * \param aft_row Determines the audio file to change.
 166  * \param percent The position to re-insert the audio file.
 167  *
 168  * The percent parameter must be between \p 0 and 100 and. A value of zero
 169  * means to re-insert the audio file into the score table with a score lower
 170  * than any other admissible file.
 171  *
 172  * \return Positive on success, negative on errors. Possible errors: Errors
 173  * returned by osl_get_row(), get_num_admissible_files(), osl_get_nth_row(),
 174  * osl_get_object(), osl_update_object().
 175  */
 176 int score_update(const struct osl_row *aft_row, long percent)
 177 {
 178         struct osl_row *row;
 179         long new_score;
 180         unsigned n, new_pos;
 181         struct osl_object obj = {.data = (struct osl_row *)aft_row,
 182                 .size = sizeof(aft_row)};
 183         int ret = osl_get_row(score_table, SCORECOL_AFT_ROW, &obj, &row);
 184
 185         if (ret < 0)
 186                 return ret;
 187         ret = get_num_admissible_files(&n);
 188         if (ret < 0)
 189                 return ret;
 190         new_pos = 1 + (n - 1) * percent / 100;
 191         ret = get_nth_score(new_pos, &new_score);
 192         if (ret < 0)
 193                 return ret;
 194         new_score--;
 195         obj.size = sizeof(long);
 196         obj.data = para_malloc(obj.size);
 197         *(long *)obj.data = new_score;
 198         PARA_DEBUG_LOG("new score: %ld, rank %u/%u\n", new_score, new_pos, n);
 199         return osl_update_object(score_table, row, SCORECOL_SCORE, &obj);
 200 }
 201
 202 /**
 203  * Given an admissible file, get the corresponding row in the aft and the score.
 204  *
 205  * \param score_row Determines the admissible file.
 206  * \param score Result pointer.
 207  * \param aft_row Result pointer.
 208  *
 209  * \return Negative on errors, positive on success. Possible errors: Errors
 210  * returned by osl_get_object().
 211  */
 212 int get_score_and_aft_row(struct osl_row *score_row, long *score,
 213                 struct osl_row **aft_row)
 214 {
 215         struct osl_object obj;
 216         int ret = get_score_of_row(score_row, score);
 217
 218         if (ret < 0)
 219                 return ret;
 220         ret = osl_get_object(score_table, score_row, SCORECOL_AFT_ROW, &obj);
 221         if (ret < 0)
 222                 return ret;
 223         *aft_row = obj.data;
 224         return 1;
 225 }
 226
 227 static int get_score_row_from_aft_row(const struct osl_row *aft_row,
 228                 struct osl_row **score_row)
 229 {
 230         struct osl_object obj = {.data = (struct osl_row *)aft_row,
 231                 .size = sizeof(aft_row)};
 232         return osl_get_row(score_table, SCORECOL_AFT_ROW, &obj, score_row);
 233
 234 }
 235
 236 /**
 237  * Loop over all files in the score table.
 238  *
 239  * \param data A pointer to arbitrary data.
 240  * \param func Function to be called for each admissible file.
 241  *
 242  * \return The return value of the underlying call to osl_rbtree_loop().
 243  *
 244  * This is used for the ls command. The \a data parameter is passed as the
 245  * second argument to \a func.
 246  *
 247  * \sa admissible_file_loop_reverse().
 248  */
 249 int admissible_file_loop(void *data, osl_rbtree_loop_func *func)
 250 {
 251         return osl_rbtree_loop(score_table, SCORECOL_SCORE, data, func);
 252 }
 253
 254 /**
 255  * Loop over all files in the score table in reverse order.
 256  *
 257  * \param data As in admissible_file_loop().
 258  * \param func As in admissible_file_loop().
 259  *
 260  * \return Same return value as admissible_file_loop().
 261  *
 262  * \sa admissible_file_loop(), osl_rbtree_loop_reverse().
 263  */
 264 int admissible_file_loop_reverse(void *data, osl_rbtree_loop_func *func)
 265 {
 266         return osl_rbtree_loop_reverse(score_table, SCORECOL_SCORE, data, func);
 267 }
 268
 269 /**
 270  * Get the admissible audio file with highest score.
 271  *
 272  * \param aft_row Points to the row in the aft of the "best" audio file.
 273  * \param score Highest score value in the score table.
 274  *
 275  * \return Positive on success, negative on errors. Possible errors: Errors
 276  * returned by osl_rbtree_last_row(), osl_get_object().
 277  */
 278 int score_get_best(struct osl_row **aft_row, long *score)
 279 {
 280         struct osl_row *row;
 281         struct osl_object obj;
 282         int ret = osl_rbtree_last_row(score_table, SCORECOL_SCORE, &row);
 283
 284         if (ret < 0)
 285                 return ret;
 286         ret = osl_get_object(score_table, row, SCORECOL_AFT_ROW, &obj);
 287         if (ret < 0)
 288                 return ret;
 289         *aft_row = obj.data;
 290         return get_score_of_row(row, score);
 291 }
 292
 293 /**
 294  * Remove an entry from the rbtree of admissible files.
 295  *
 296  * \param aft_row The file which is no longer admissible.
 297  *
 298  * \return Positive on success, negative on errors. Possible errors:
 299  * Errors returned by osl_get_row() and osl_del_row().
 300  *
 301  * \sa score_add(), score_shutdown().
 302  */
 303 int score_delete(const struct osl_row *aft_row)
 304 {
 305         struct osl_row *score_row;
 306         int ret = get_score_row_from_aft_row(aft_row, &score_row);
 307
 308         if (ret < 0)
 309                 return ret;
 310         return osl_del_row(score_table, score_row);
 311 }
 312
 313 /**
 314  * Find out whether an audio file is contained in the score table.
 315  *
 316  * \param aft_row The row of the audio file table.
 317  * \param rank Result pointer
 318  *
 319  * \return Positive, if \a aft_row belongs to the audio file table,
 320  * zero if not, negative on errors. If \a aft_row was found, and \a rank
 321  * is not \p NULL, the rank of \a aft_row is returned in \a rank.
 322  */
 323 int row_belongs_to_score_table(const struct osl_row *aft_row, unsigned *rank)
 324 {
 325         struct osl_row *score_row;
 326         int ret = get_score_row_from_aft_row(aft_row, &score_row);
 327
 328         if (ret == -E_RB_KEY_NOT_FOUND)
 329                 return 0;
 330         if (ret < 0)
 331                 return ret;
 332         if (!rank)
 333                 return 1;
 334         ret = osl_get_rank(score_table, score_row, SCORECOL_SCORE, rank);
 335         if (ret < 0)
 336                 return ret;
 337         return 1;
 338 }
 339
 340 /* Close the score table. */
 341 static void score_close(void)
 342 {
 343         osl_close_table(score_table, OSL_FREE_VOLATILE);
 344         score_table = NULL;
 345 }
 346
 347 /**
 348  * Open the score table.
 349  *
 350  * \param dir Unused.
 351  *
 352  * \return The return value of the underlying call to osl_open_table().
 353  */
 354 static int score_open(__a_unused const char *dir)
 355 {
 356         score_table_desc.dir = NULL; /* this table has only volatile columns */
 357         return osl_open_table(&score_table_desc, &score_table);
 358 }
 359
 360 /**
 361  * Remove all entries from the score table, but keep the table open.
 362  *
 363  * \return Standard.
 364  */
 365 int clear_score_table(void)
 366 {
 367         score_close();
 368         return score_open(NULL);
 369 }
 370
 371 static int score_event_handler(__a_unused enum afs_events event,
 372                 __a_unused struct para_buffer *pb, __a_unused void *data)
 373 {
 374         return 1;
 375 }
 376
 377 /**
 378  * Initialize the scoring subsystem.
 379  *
 380  * \param t The members of \a t are filled in by the function.
 381  */
 382 void score_init(struct afs_table *t)
 383 {
 384         t->name = score_table_desc.name;
 385         t->open = score_open;
 386         t->close = score_close;
 387         t->event_handler = score_event_handler;
 388 }