sound/core/seq/seq_prioq.c

   1 /*
   2  *   ALSA sequencer Priority Queue
   3  *   Copyright (c) 1998-1999 by Frank van de Pol <fvdpol@coil.demon.nl>
   4  *
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  *
  20  */
  21
  22 #include <linux/time.h>
  23 #include <linux/slab.h>
  24 #include <sound/core.h>
  25 #include "seq_timer.h"
  26 #include "seq_prioq.h"
  27
  28
  29 /* Implementation is a simple linked list for now...
  30
  31    This priority queue orders the events on timestamp. For events with an
  32    equeal timestamp the queue behaves as a FIFO.
  33
  34    *
  35    *           +-------+
  36    *  Head --> | first |
  37    *           +-------+
  38    *                 |next
  39    *           +-----v-+
  40    *           |       |
  41    *           +-------+
  42    *                 |
  43    *           +-----v-+
  44    *           |       |
  45    *           +-------+
  46    *                 |
  47    *           +-----v-+
  48    *  Tail --> | last  |
  49    *           +-------+
  50    *
  51
  52  */
  53
  54
  55
  56 /* create new prioq (constructor) */
  57 struct snd_seq_prioq *snd_seq_prioq_new(void)
  58 {
  59         struct snd_seq_prioq *f;
  60
  61         f = kzalloc(sizeof(*f), GFP_KERNEL);
  62         if (!f)
  63                 return NULL;
  64
  65         spin_lock_init(&f->lock);
  66         f->head = NULL;
  67         f->tail = NULL;
  68         f->cells = 0;
  69
  70         return f;
  71 }
  72
  73 /* delete prioq (destructor) */
  74 void snd_seq_prioq_delete(struct snd_seq_prioq **fifo)
  75 {
  76         struct snd_seq_prioq *f = *fifo;
  77         *fifo = NULL;
  78
  79         if (f == NULL) {
  80                 pr_debug("ALSA: seq: snd_seq_prioq_delete() called with NULL prioq\n");
  81                 return;
  82         }
  83
  84         /* release resources...*/
  85         /*....................*/
  86
  87         if (f->cells > 0) {
  88                 /* drain prioQ */
  89                 while (f->cells > 0)
  90                         snd_seq_cell_free(snd_seq_prioq_cell_out(f, NULL));
  91         }
  92
  93         kfree(f);
  94 }
  95
  96
  97
  98
  99 /* compare timestamp between events */
 100 /* return 1 if a >= b; 0 */
 101 static inline int compare_timestamp(struct snd_seq_event *a,
 102                                     struct snd_seq_event *b)
 103 {
 104         if ((a->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) {
 105                 /* compare ticks */
 106                 return (snd_seq_compare_tick_time(&a->time.tick, &b->time.tick));
 107         } else {
 108                 /* compare real time */
 109                 return (snd_seq_compare_real_time(&a->time.time, &b->time.time));
 110         }
 111 }
 112
 113 /* compare timestamp between events */
 114 /* return negative if a < b;
 115  *        zero     if a = b;
 116  *        positive if a > b;
 117  */
 118 static inline int compare_timestamp_rel(struct snd_seq_event *a,
 119                                         struct snd_seq_event *b)
 120 {
 121         if ((a->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK) {
 122                 /* compare ticks */
 123                 if (a->time.tick > b->time.tick)
 124                         return 1;
 125                 else if (a->time.tick == b->time.tick)
 126                         return 0;
 127                 else
 128                         return -1;
 129         } else {
 130                 /* compare real time */
 131                 if (a->time.time.tv_sec > b->time.time.tv_sec)
 132                         return 1;
 133                 else if (a->time.time.tv_sec == b->time.time.tv_sec) {
 134                         if (a->time.time.tv_nsec > b->time.time.tv_nsec)
 135                                 return 1;
 136                         else if (a->time.time.tv_nsec == b->time.time.tv_nsec)
 137                                 return 0;
 138                         else
 139                                 return -1;
 140                 } else
 141                         return -1;
 142         }
 143 }
 144
 145 /* enqueue cell to prioq */
 146 int snd_seq_prioq_cell_in(struct snd_seq_prioq * f,
 147                           struct snd_seq_event_cell * cell)
 148 {
 149         struct snd_seq_event_cell *cur, *prev;
 150         unsigned long flags;
 151         int count;
 152         int prior;
 153
 154         if (snd_BUG_ON(!f || !cell))
 155                 return -EINVAL;
 156
 157         /* check flags */
 158         prior = (cell->event.flags & SNDRV_SEQ_PRIORITY_MASK);
 159
 160         spin_lock_irqsave(&f->lock, flags);
 161
 162         /* check if this element needs to inserted at the end (ie. ordered
 163            data is inserted) This will be very likeley if a sequencer
 164            application or midi file player is feeding us (sequential) data */
 165         if (f->tail && !prior) {
 166                 if (compare_timestamp(&cell->event, &f->tail->event)) {
 167                         /* add new cell to tail of the fifo */
 168                         f->tail->next = cell;
 169                         f->tail = cell;
 170                         cell->next = NULL;
 171                         f->cells++;
 172                         spin_unlock_irqrestore(&f->lock, flags);
 173                         return 0;
 174                 }
 175         }
 176         /* traverse list of elements to find the place where the new cell is
 177            to be inserted... Note that this is a order n process ! */
 178
 179         prev = NULL;            /* previous cell */
 180         cur = f->head;          /* cursor */
 181
 182         count = 10000; /* FIXME: enough big, isn't it? */
 183         while (cur != NULL) {
 184                 /* compare timestamps */
 185                 int rel = compare_timestamp_rel(&cell->event, &cur->event);
 186                 if (rel < 0)
 187                         /* new cell has earlier schedule time, */
 188                         break;
 189                 else if (rel == 0 && prior)
 190                         /* equal schedule time and prior to others */
 191                         break;
 192                 /* new cell has equal or larger schedule time, */
 193                 /* move cursor to next cell */
 194                 prev = cur;
 195                 cur = cur->next;
 196                 if (! --count) {
 197                         spin_unlock_irqrestore(&f->lock, flags);
 198                         pr_err("ALSA: seq: cannot find a pointer.. infinite loop?\n");
 199                         return -EINVAL;
 200                 }
 201         }
 202
 203         /* insert it before cursor */
 204         if (prev != NULL)
 205                 prev->next = cell;
 206         cell->next = cur;
 207
 208         if (f->head == cur) /* this is the first cell, set head to it */
 209                 f->head = cell;
 210         if (cur == NULL) /* reached end of the list */
 211                 f->tail = cell;
 212         f->cells++;
 213         spin_unlock_irqrestore(&f->lock, flags);
 214         return 0;
 215 }
 216
 217 /* return 1 if the current time >= event timestamp */
 218 static int event_is_ready(struct snd_seq_event *ev, void *current_time)
 219 {
 220         if ((ev->flags & SNDRV_SEQ_TIME_STAMP_MASK) == SNDRV_SEQ_TIME_STAMP_TICK)
 221                 return snd_seq_compare_tick_time(current_time, &ev->time.tick);
 222         else
 223                 return snd_seq_compare_real_time(current_time, &ev->time.time);
 224 }
 225
 226 /* dequeue cell from prioq */
 227 struct snd_seq_event_cell *snd_seq_prioq_cell_out(struct snd_seq_prioq *f,
 228                                                   void *current_time)
 229 {
 230         struct snd_seq_event_cell *cell;
 231         unsigned long flags;
 232
 233         if (f == NULL) {
 234                 pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n");
 235                 return NULL;
 236         }
 237         spin_lock_irqsave(&f->lock, flags);
 238
 239         cell = f->head;
 240         if (cell && current_time && !event_is_ready(&cell->event, current_time))
 241                 cell = NULL;
 242         if (cell) {
 243                 f->head = cell->next;
 244
 245                 /* reset tail if this was the last element */
 246                 if (f->tail == cell)
 247                         f->tail = NULL;
 248
 249                 cell->next = NULL;
 250                 f->cells--;
 251         }
 252
 253         spin_unlock_irqrestore(&f->lock, flags);
 254         return cell;
 255 }
 256
 257 /* return number of events available in prioq */
 258 int snd_seq_prioq_avail(struct snd_seq_prioq * f)
 259 {
 260         if (f == NULL) {
 261                 pr_debug("ALSA: seq: snd_seq_prioq_cell_in() called with NULL prioq\n");
 262                 return 0;
 263         }
 264         return f->cells;
 265 }
 266
 267 static inline int prioq_match(struct snd_seq_event_cell *cell,
 268                               int client, int timestamp)
 269 {
 270         if (cell->event.source.client == client ||
 271             cell->event.dest.client == client)
 272                 return 1;
 273         if (!timestamp)
 274                 return 0;
 275         switch (cell->event.flags & SNDRV_SEQ_TIME_STAMP_MASK) {
 276         case SNDRV_SEQ_TIME_STAMP_TICK:
 277                 if (cell->event.time.tick)
 278                         return 1;
 279                 break;
 280         case SNDRV_SEQ_TIME_STAMP_REAL:
 281                 if (cell->event.time.time.tv_sec ||
 282                     cell->event.time.time.tv_nsec)
 283                         return 1;
 284                 break;
 285         }
 286         return 0;
 287 }
 288
 289 /* remove cells for left client */
 290 void snd_seq_prioq_leave(struct snd_seq_prioq * f, int client, int timestamp)
 291 {
 292         register struct snd_seq_event_cell *cell, *next;
 293         unsigned long flags;
 294         struct snd_seq_event_cell *prev = NULL;
 295         struct snd_seq_event_cell *freefirst = NULL, *freeprev = NULL, *freenext;
 296
 297         /* collect all removed cells */
 298         spin_lock_irqsave(&f->lock, flags);
 299         cell = f->head;
 300         while (cell) {
 301                 next = cell->next;
 302                 if (prioq_match(cell, client, timestamp)) {
 303                         /* remove cell from prioq */
 304                         if (cell == f->head) {
 305                                 f->head = cell->next;
 306                         } else {
 307                                 prev->next = cell->next;
 308                         }
 309                         if (cell == f->tail)
 310                                 f->tail = cell->next;
 311                         f->cells--;
 312                         /* add cell to free list */
 313                         cell->next = NULL;
 314                         if (freefirst == NULL) {
 315                                 freefirst = cell;
 316                         } else {
 317                                 freeprev->next = cell;
 318                         }
 319                         freeprev = cell;
 320                 } else {
 321 #if 0
 322                         pr_debug("ALSA: seq: type = %i, source = %i, dest = %i, "
 323                                "client = %i\n",
 324                                 cell->event.type,
 325                                 cell->event.source.client,
 326                                 cell->event.dest.client,
 327                                 client);
 328 #endif
 329                         prev = cell;
 330                 }
 331                 cell = next;
 332         }
 333         spin_unlock_irqrestore(&f->lock, flags);
 334
 335         /* remove selected cells */
 336         while (freefirst) {
 337                 freenext = freefirst->next;
 338                 snd_seq_cell_free(freefirst);
 339                 freefirst = freenext;
 340         }
 341 }
 342
 343 static int prioq_remove_match(struct snd_seq_remove_events *info,
 344                               struct snd_seq_event *ev)
 345 {
 346         int res;
 347
 348         if (info->remove_mode & SNDRV_SEQ_REMOVE_DEST) {
 349                 if (ev->dest.client != info->dest.client ||
 350                                 ev->dest.port != info->dest.port)
 351                         return 0;
 352         }
 353         if (info->remove_mode & SNDRV_SEQ_REMOVE_DEST_CHANNEL) {
 354                 if (! snd_seq_ev_is_channel_type(ev))
 355                         return 0;
 356                 /* data.note.channel and data.control.channel are identical */
 357                 if (ev->data.note.channel != info->channel)
 358                         return 0;
 359         }
 360         if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_AFTER) {
 361                 if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_TICK)
 362                         res = snd_seq_compare_tick_time(&ev->time.tick, &info->time.tick);
 363                 else
 364                         res = snd_seq_compare_real_time(&ev->time.time, &info->time.time);
 365                 if (!res)
 366                         return 0;
 367         }
 368         if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_BEFORE) {
 369                 if (info->remove_mode & SNDRV_SEQ_REMOVE_TIME_TICK)
 370                         res = snd_seq_compare_tick_time(&ev->time.tick, &info->time.tick);
 371                 else
 372                         res = snd_seq_compare_real_time(&ev->time.time, &info->time.time);
 373                 if (res)
 374                         return 0;
 375         }
 376         if (info->remove_mode & SNDRV_SEQ_REMOVE_EVENT_TYPE) {
 377                 if (ev->type != info->type)
 378                         return 0;
 379         }
 380         if (info->remove_mode & SNDRV_SEQ_REMOVE_IGNORE_OFF) {
 381                 /* Do not remove off events */
 382                 switch (ev->type) {
 383                 case SNDRV_SEQ_EVENT_NOTEOFF:
 384                 /* case SNDRV_SEQ_EVENT_SAMPLE_STOP: */
 385                         return 0;
 386                 default:
 387                         break;
 388                 }
 389         }
 390         if (info->remove_mode & SNDRV_SEQ_REMOVE_TAG_MATCH) {
 391                 if (info->tag != ev->tag)
 392                         return 0;
 393         }
 394
 395         return 1;
 396 }
 397
 398 /* remove cells matching remove criteria */
 399 void snd_seq_prioq_remove_events(struct snd_seq_prioq * f, int client,
 400                                  struct snd_seq_remove_events *info)
 401 {
 402         struct snd_seq_event_cell *cell, *next;
 403         unsigned long flags;
 404         struct snd_seq_event_cell *prev = NULL;
 405         struct snd_seq_event_cell *freefirst = NULL, *freeprev = NULL, *freenext;
 406
 407         /* collect all removed cells */
 408         spin_lock_irqsave(&f->lock, flags);
 409         cell = f->head;
 410
 411         while (cell) {
 412                 next = cell->next;
 413                 if (cell->event.source.client == client &&
 414                         prioq_remove_match(info, &cell->event)) {
 415
 416                         /* remove cell from prioq */
 417                         if (cell == f->head) {
 418                                 f->head = cell->next;
 419                         } else {
 420                                 prev->next = cell->next;
 421                         }
 422
 423                         if (cell == f->tail)
 424                                 f->tail = cell->next;
 425                         f->cells--;
 426
 427                         /* add cell to free list */
 428                         cell->next = NULL;
 429                         if (freefirst == NULL) {
 430                                 freefirst = cell;
 431                         } else {
 432                                 freeprev->next = cell;
 433                         }
 434
 435                         freeprev = cell;
 436                 } else {
 437                         prev = cell;
 438                 }
 439                 cell = next;
 440         }
 441         spin_unlock_irqrestore(&f->lock, flags);
 442
 443         /* remove selected cells */
 444         while (freefirst) {
 445                 freenext = freefirst->next;
 446                 snd_seq_cell_free(freefirst);
 447                 freefirst = freenext;
 448         }
 449 }
 450
 451