src/pulsecore/memblockq.c

   1 /***
   2   This file is part of PulseAudio.
   3
   4   Copyright 2004-2006 Lennart Poettering
   5
   6   PulseAudio is free software; you can redistribute it and/or modify
   7   it under the terms of the GNU Lesser General Public License as published
   8   by the Free Software Foundation; either version 2.1 of the License,
   9   or (at your option) any later version.
  10
  11   PulseAudio is distributed in the hope that it will be useful, but
  12   WITHOUT ANY WARRANTY; without even the implied warranty of
  13   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14   General Public License for more details.
  15
  16   You should have received a copy of the GNU Lesser General Public License
  17   along with PulseAudio; if not, write to the Free Software
  18   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
  19   USA.
  20 ***/
  21
  22 #ifdef HAVE_CONFIG_H
  23 #include <config.h>
  24 #endif
  25
  26 #include <sys/time.h>
  27 #include <time.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31
  32 #include <pulse/xmalloc.h>
  33
  34 #include <pulsecore/log.h>
  35 #include <pulsecore/mcalign.h>
  36 #include <pulsecore/macro.h>
  37 #include <pulsecore/flist.h>
  38
  39 #include "memblockq.h"
  40
  41 struct list_item {
  42     struct list_item *next, *prev;
  43     int64_t index;
  44     pa_memchunk chunk;
  45 };
  46
  47 PA_STATIC_FLIST_DECLARE(list_items, 0, pa_xfree);
  48
  49 struct pa_memblockq {
  50     struct list_item *blocks, *blocks_tail;
  51     struct list_item *current_read, *current_write;
  52     unsigned n_blocks;
  53     size_t maxlength, tlength, base, prebuf, minreq, maxrewind;
  54     int64_t read_index, write_index;
  55     pa_bool_t in_prebuf;
  56     pa_memchunk silence;
  57     pa_mcalign *mcalign;
  58     int64_t missing, requested;
  59 };
  60
  61 pa_memblockq* pa_memblockq_new(
  62         int64_t idx,
  63         size_t maxlength,
  64         size_t tlength,
  65         size_t base,
  66         size_t prebuf,
  67         size_t minreq,
  68         size_t maxrewind,
  69         pa_memchunk *silence) {
  70
  71     pa_memblockq* bq;
  72
  73     pa_assert(base > 0);
  74
  75     bq = pa_xnew(pa_memblockq, 1);
  76     bq->blocks = bq->blocks_tail = NULL;
  77     bq->current_read = bq->current_write = NULL;
  78     bq->n_blocks = 0;
  79
  80     bq->base = base;
  81     bq->read_index = bq->write_index = idx;
  82
  83     pa_log_debug("memblockq requested: maxlength=%lu, tlength=%lu, base=%lu, prebuf=%lu, minreq=%lu maxrewind=%lu",
  84                  (unsigned long) maxlength, (unsigned long) tlength, (unsigned long) base, (unsigned long) prebuf, (unsigned long) minreq, (unsigned long) maxrewind);
  85
  86     bq->missing = bq->requested = 0;
  87     bq->maxlength = bq->tlength = bq->prebuf = bq->minreq = bq->maxrewind = 0;
  88     bq->in_prebuf = TRUE;
  89
  90     pa_memblockq_set_maxlength(bq, maxlength);
  91     pa_memblockq_set_tlength(bq, tlength);
  92     pa_memblockq_set_minreq(bq, minreq);
  93     pa_memblockq_set_prebuf(bq, prebuf);
  94     pa_memblockq_set_maxrewind(bq, maxrewind);
  95
  96     pa_log_debug("memblockq sanitized: maxlength=%lu, tlength=%lu, base=%lu, prebuf=%lu, minreq=%lu maxrewind=%lu",
  97                  (unsigned long) bq->maxlength, (unsigned long) bq->tlength, (unsigned long) bq->base, (unsigned long) bq->prebuf, (unsigned long) bq->minreq, (unsigned long) bq->maxrewind);
  98
  99     if (silence) {
 100         bq->silence = *silence;
 101         pa_memblock_ref(bq->silence.memblock);
 102     } else
 103         pa_memchunk_reset(&bq->silence);
 104
 105     bq->mcalign = pa_mcalign_new(bq->base);
 106
 107     return bq;
 108 }
 109
 110 void pa_memblockq_free(pa_memblockq* bq) {
 111     pa_assert(bq);
 112
 113     pa_memblockq_silence(bq);
 114
 115     if (bq->silence.memblock)
 116         pa_memblock_unref(bq->silence.memblock);
 117
 118     if (bq->mcalign)
 119         pa_mcalign_free(bq->mcalign);
 120
 121     pa_xfree(bq);
 122 }
 123
 124 static void fix_current_read(pa_memblockq *bq) {
 125     pa_assert(bq);
 126
 127     if (PA_UNLIKELY(!bq->blocks)) {
 128         bq->current_read = NULL;
 129         return;
 130     }
 131
 132     if (PA_UNLIKELY(!bq->current_read))
 133         bq->current_read = bq->blocks;
 134
 135     /* Scan left */
 136     while (PA_UNLIKELY(bq->current_read->index > bq->read_index))
 137
 138         if (bq->current_read->prev)
 139             bq->current_read = bq->current_read->prev;
 140         else
 141             break;
 142
 143     /* Scan right */
 144     while (PA_LIKELY(bq->current_read != NULL) && PA_UNLIKELY(bq->current_read->index + (int64_t) bq->current_read->chunk.length <= bq->read_index))
 145         bq->current_read = bq->current_read->next;
 146
 147     /* At this point current_read will either point at or left of the
 148        next block to play. It may be NULL in case everything in
 149        the queue was already played */
 150 }
 151
 152 static void fix_current_write(pa_memblockq *bq) {
 153     pa_assert(bq);
 154
 155     if (PA_UNLIKELY(!bq->blocks)) {
 156         bq->current_write = NULL;
 157         return;
 158     }
 159
 160     if (PA_UNLIKELY(!bq->current_write))
 161         bq->current_write = bq->blocks_tail;
 162
 163     /* Scan right */
 164     while (PA_UNLIKELY(bq->current_write->index + (int64_t) bq->current_write->chunk.length <= bq->write_index))
 165
 166         if (bq->current_write->next)
 167             bq->current_write = bq->current_write->next;
 168         else
 169             break;
 170
 171     /* Scan left */
 172     while (PA_LIKELY(bq->current_write != NULL) && PA_UNLIKELY(bq->current_write->index > bq->write_index))
 173         bq->current_write = bq->current_write->prev;
 174
 175     /* At this point current_write will either point at or right of
 176        the next block to write data to. It may be NULL in case
 177        everything in the queue is still to be played */
 178 }
 179
 180 static void drop_block(pa_memblockq *bq, struct list_item *q) {
 181     pa_assert(bq);
 182     pa_assert(q);
 183
 184     pa_assert(bq->n_blocks >= 1);
 185
 186     if (q->prev)
 187         q->prev->next = q->next;
 188     else {
 189         pa_assert(bq->blocks == q);
 190         bq->blocks = q->next;
 191     }
 192
 193     if (q->next)
 194         q->next->prev = q->prev;
 195     else {
 196         pa_assert(bq->blocks_tail == q);
 197         bq->blocks_tail = q->prev;
 198     }
 199
 200     if (bq->current_write == q)
 201         bq->current_write = q->prev;
 202
 203     if (bq->current_read == q)
 204         bq->current_read = q->next;
 205
 206     pa_memblock_unref(q->chunk.memblock);
 207
 208     if (pa_flist_push(PA_STATIC_FLIST_GET(list_items), q) < 0)
 209         pa_xfree(q);
 210
 211     bq->n_blocks--;
 212 }
 213
 214 static void drop_backlog(pa_memblockq *bq) {
 215     int64_t boundary;
 216     pa_assert(bq);
 217
 218     boundary = bq->read_index - (int64_t) bq->maxrewind;
 219
 220     while (bq->blocks && (bq->blocks->index + (int64_t) bq->blocks->chunk.length <= boundary))
 221         drop_block(bq, bq->blocks);
 222 }
 223
 224 static pa_bool_t can_push(pa_memblockq *bq, size_t l) {
 225     int64_t end;
 226
 227     pa_assert(bq);
 228
 229     if (bq->read_index > bq->write_index) {
 230         int64_t d = bq->read_index - bq->write_index;
 231
 232         if ((int64_t) l > d)
 233             l -= (size_t) d;
 234         else
 235             return TRUE;
 236     }
 237
 238     end = bq->blocks_tail ? bq->blocks_tail->index + (int64_t) bq->blocks_tail->chunk.length : bq->write_index;
 239
 240     /* Make sure that the list doesn't get too long */
 241     if (bq->write_index + (int64_t) l > end)
 242         if (bq->write_index + (int64_t) l - bq->read_index > (int64_t) bq->maxlength)
 243             return FALSE;
 244
 245     return TRUE;
 246 }
 247
 248 static void write_index_changed(pa_memblockq *bq, int64_t old_write_index, pa_bool_t account) {
 249     int64_t delta;
 250
 251     pa_assert(bq);
 252
 253     delta = bq->write_index - old_write_index;
 254
 255     if (account)
 256         bq->requested -= delta;
 257     else
 258         bq->missing -= delta;
 259
 260     /* pa_log("pushed/seeked %lli: requested counter at %lli, account=%i", (long long) delta, (long long) bq->requested, account); */
 261 }
 262
 263 static void read_index_changed(pa_memblockq *bq, int64_t old_read_index) {
 264     int64_t delta;
 265
 266     pa_assert(bq);
 267
 268     delta = bq->read_index - old_read_index;
 269     bq->missing += delta;
 270
 271     /* pa_log("popped %lli: missing counter at %lli", (long long) delta, (long long) bq->missing); */
 272 }
 273
 274 int pa_memblockq_push(pa_memblockq* bq, const pa_memchunk *uchunk) {
 275     struct list_item *q, *n;
 276     pa_memchunk chunk;
 277     int64_t old;
 278
 279     pa_assert(bq);
 280     pa_assert(uchunk);
 281     pa_assert(uchunk->memblock);
 282     pa_assert(uchunk->length > 0);
 283     pa_assert(uchunk->index + uchunk->length <= pa_memblock_get_length(uchunk->memblock));
 284
 285     if (uchunk->length % bq->base)
 286         return -1;
 287
 288     if (!can_push(bq, uchunk->length))
 289         return -1;
 290
 291     old = bq->write_index;
 292     chunk = *uchunk;
 293
 294     fix_current_write(bq);
 295     q = bq->current_write;
 296
 297     /* First we advance the q pointer right of where we want to
 298      * write to */
 299
 300     if (q) {
 301         while (bq->write_index + (int64_t) chunk.length > q->index)
 302             if (q->next)
 303                 q = q->next;
 304             else
 305                 break;
 306     }
 307
 308     if (!q)
 309         q = bq->blocks_tail;
 310
 311     /* We go from back to front to look for the right place to add
 312      * this new entry. Drop data we will overwrite on the way */
 313
 314     while (q) {
 315
 316         if (bq->write_index >= q->index + (int64_t) q->chunk.length)
 317             /* We found the entry where we need to place the new entry immediately after */
 318             break;
 319         else if (bq->write_index + (int64_t) chunk.length <= q->index) {
 320             /* This entry isn't touched at all, let's skip it */
 321             q = q->prev;
 322         } else if (bq->write_index <= q->index &&
 323                    bq->write_index + (int64_t) chunk.length >= q->index + (int64_t) q->chunk.length) {
 324
 325             /* This entry is fully replaced by the new entry, so let's drop it */
 326
 327             struct list_item *p;
 328             p = q;
 329             q = q->prev;
 330             drop_block(bq, p);
 331         } else if (bq->write_index >= q->index) {
 332             /* The write index points into this memblock, so let's
 333              * truncate or split it */
 334
 335             if (bq->write_index + (int64_t) chunk.length < q->index + (int64_t) q->chunk.length) {
 336
 337                 /* We need to save the end of this memchunk */
 338                 struct list_item *p;
 339                 size_t d;
 340
 341                 /* Create a new list entry for the end of thie memchunk */
 342                 if (!(p = pa_flist_pop(PA_STATIC_FLIST_GET(list_items))))
 343                     p = pa_xnew(struct list_item, 1);
 344
 345                 p->chunk = q->chunk;
 346                 pa_memblock_ref(p->chunk.memblock);
 347
 348                 /* Calculate offset */
 349                 d = (size_t) (bq->write_index + (int64_t) chunk.length - q->index);
 350                 pa_assert(d > 0);
 351
 352                 /* Drop it from the new entry */
 353                 p->index = q->index + (int64_t) d;
 354                 p->chunk.length -= d;
 355
 356                 /* Add it to the list */
 357                 p->prev = q;
 358                 if ((p->next = q->next))
 359                     q->next->prev = p;
 360                 else
 361                     bq->blocks_tail = p;
 362                 q->next = p;
 363
 364                 bq->n_blocks++;
 365             }
 366
 367             /* Truncate the chunk */
 368             if (!(q->chunk.length = (size_t) (bq->write_index - q->index))) {
 369                 struct list_item *p;
 370                 p = q;
 371                 q = q->prev;
 372                 drop_block(bq, p);
 373             }
 374
 375             /* We had to truncate this block, hence we're now at the right position */
 376             break;
 377         } else {
 378             size_t d;
 379
 380             pa_assert(bq->write_index + (int64_t)chunk.length > q->index &&
 381                    bq->write_index + (int64_t)chunk.length < q->index + (int64_t)q->chunk.length &&
 382                    bq->write_index < q->index);
 383
 384             /* The job overwrites the current entry at the end, so let's drop the beginning of this entry */
 385
 386             d = (size_t) (bq->write_index + (int64_t) chunk.length - q->index);
 387             q->index += (int64_t) d;
 388             q->chunk.index += d;
 389             q->chunk.length -= d;
 390
 391             q = q->prev;
 392         }
 393     }
 394
 395     if (q) {
 396         pa_assert(bq->write_index >=  q->index + (int64_t)q->chunk.length);
 397         pa_assert(!q->next || (bq->write_index + (int64_t)chunk.length <= q->next->index));
 398
 399         /* Try to merge memory blocks */
 400
 401         if (q->chunk.memblock == chunk.memblock &&
 402             q->chunk.index + q->chunk.length == chunk.index &&
 403             bq->write_index == q->index + (int64_t) q->chunk.length) {
 404
 405             q->chunk.length += chunk.length;
 406             bq->write_index += (int64_t) chunk.length;
 407             goto finish;
 408         }
 409     } else
 410         pa_assert(!bq->blocks || (bq->write_index + (int64_t)chunk.length <= bq->blocks->index));
 411
 412     if (!(n = pa_flist_pop(PA_STATIC_FLIST_GET(list_items))))
 413         n = pa_xnew(struct list_item, 1);
 414
 415     n->chunk = chunk;
 416     pa_memblock_ref(n->chunk.memblock);
 417     n->index = bq->write_index;
 418     bq->write_index += (int64_t) n->chunk.length;
 419
 420     n->next = q ? q->next : bq->blocks;
 421     n->prev = q;
 422
 423     if (n->next)
 424         n->next->prev = n;
 425     else
 426         bq->blocks_tail = n;
 427
 428     if (n->prev)
 429         n->prev->next = n;
 430     else
 431         bq->blocks = n;
 432
 433     bq->n_blocks++;
 434
 435 finish:
 436
 437     write_index_changed(bq, old, TRUE);
 438     return 0;
 439 }
 440
 441 pa_bool_t pa_memblockq_prebuf_active(pa_memblockq *bq) {
 442     pa_assert(bq);
 443
 444     if (bq->in_prebuf)
 445         return pa_memblockq_get_length(bq) < bq->prebuf;
 446     else
 447         return bq->prebuf > 0 && bq->read_index >= bq->write_index;
 448 }
 449
 450 static pa_bool_t update_prebuf(pa_memblockq *bq) {
 451     pa_assert(bq);
 452
 453     if (bq->in_prebuf) {
 454
 455         if (pa_memblockq_get_length(bq) < bq->prebuf)
 456             return TRUE;
 457
 458         bq->in_prebuf = FALSE;
 459         return FALSE;
 460     } else {
 461
 462         if (bq->prebuf > 0 && bq->read_index >= bq->write_index) {
 463             bq->in_prebuf = TRUE;
 464             return TRUE;
 465         }
 466
 467         return FALSE;
 468     }
 469 }
 470
 471 int pa_memblockq_peek(pa_memblockq* bq, pa_memchunk *chunk) {
 472     int64_t d;
 473     pa_assert(bq);
 474     pa_assert(chunk);
 475
 476     /* We need to pre-buffer */
 477     if (update_prebuf(bq))
 478         return -1;
 479
 480     fix_current_read(bq);
 481
 482     /* Do we need to spit out silence? */
 483     if (!bq->current_read || bq->current_read->index > bq->read_index) {
 484         size_t length;
 485
 486         /* How much silence shall we return? */
 487         if (bq->current_read)
 488             length = (size_t) (bq->current_read->index - bq->read_index);
 489         else if (bq->write_index > bq->read_index)
 490             length = (size_t) (bq->write_index - bq->read_index);
 491         else
 492             length = 0;
 493
 494         /* We need to return silence, since no data is yet available */
 495         if (bq->silence.memblock) {
 496             *chunk = bq->silence;
 497             pa_memblock_ref(chunk->memblock);
 498
 499             if (length > 0 && length < chunk->length)
 500                 chunk->length = length;
 501
 502         } else {
 503
 504             /* If the memblockq is empty, return -1, otherwise return
 505              * the time to sleep */
 506             if (length <= 0)
 507                 return -1;
 508
 509             chunk->memblock = NULL;
 510             chunk->length = length;
 511         }
 512
 513         chunk->index = 0;
 514         return 0;
 515     }
 516
 517     /* Ok, let's pass real data to the caller */
 518     *chunk = bq->current_read->chunk;
 519     pa_memblock_ref(chunk->memblock);
 520
 521     pa_assert(bq->read_index >= bq->current_read->index);
 522     d = bq->read_index - bq->current_read->index;
 523     chunk->index += (size_t) d;
 524     chunk->length -= (size_t) d;
 525
 526     return 0;
 527 }
 528
 529 int pa_memblockq_peek_fixed_size(pa_memblockq *bq, size_t block_size, pa_memchunk *chunk) {
 530     pa_memchunk tchunk, rchunk;
 531     int64_t ri;
 532     struct list_item *item;
 533
 534     pa_assert(bq);
 535     pa_assert(block_size > 0);
 536     pa_assert(chunk);
 537     pa_assert(bq->silence.memblock);
 538
 539     if (pa_memblockq_peek(bq, &tchunk) < 0)
 540         return -1;
 541
 542     if (tchunk.length >= block_size) {
 543         *chunk = tchunk;
 544         chunk->length = block_size;
 545         return 0;
 546     }
 547
 548     rchunk.memblock = pa_memblock_new(pa_memblock_get_pool(tchunk.memblock), block_size);
 549     rchunk.index = 0;
 550     rchunk.length = tchunk.length;
 551
 552     pa_memchunk_memcpy(&rchunk, &tchunk);
 553     pa_memblock_unref(tchunk.memblock);
 554
 555     rchunk.index += tchunk.length;
 556
 557     /* We don't need to call fix_current_read() here, since
 558      * pa_memblock_peek() already did that */
 559     item = bq->current_read;
 560     ri = bq->read_index + tchunk.length;
 561
 562     while (rchunk.index < block_size) {
 563
 564         if (!item || item->index > ri) {
 565             /* Do we need to append silence? */
 566             tchunk = bq->silence;
 567
 568             if (item)
 569                 tchunk.length = PA_MIN(tchunk.length, (size_t) (item->index - ri));
 570
 571         } else {
 572             int64_t d;
 573
 574             /* We can append real data! */
 575             tchunk = item->chunk;
 576
 577             d = ri - item->index;
 578             tchunk.index += (size_t) d;
 579             tchunk.length -= (size_t) d;
 580
 581             /* Go to next item for the next iteration */
 582             item = item->next;
 583         }
 584
 585         rchunk.length = tchunk.length = PA_MIN(tchunk.length, block_size - rchunk.index);
 586         pa_memchunk_memcpy(&rchunk, &tchunk);
 587
 588         rchunk.index += rchunk.length;
 589         ri += rchunk.length;
 590     }
 591
 592     rchunk.index = 0;
 593     rchunk.length = block_size;
 594
 595     *chunk = rchunk;
 596     return 0;
 597 }
 598
 599 void pa_memblockq_drop(pa_memblockq *bq, size_t length) {
 600     int64_t old;
 601     pa_assert(bq);
 602     pa_assert(length % bq->base == 0);
 603
 604     old = bq->read_index;
 605
 606     while (length > 0) {
 607
 608         /* Do not drop any data when we are in prebuffering mode */
 609         if (update_prebuf(bq))
 610             break;
 611
 612         fix_current_read(bq);
 613
 614         if (bq->current_read) {
 615             int64_t p, d;
 616
 617             /* We go through this piece by piece to make sure we don't
 618              * drop more than allowed by prebuf */
 619
 620             p = bq->current_read->index + (int64_t) bq->current_read->chunk.length;
 621             pa_assert(p >= bq->read_index);
 622             d = p - bq->read_index;
 623
 624             if (d > (int64_t) length)
 625                 d = (int64_t) length;
 626
 627             bq->read_index += d;
 628             length -= (size_t) d;
 629
 630         } else {
 631
 632             /* The list is empty, there's nothing we could drop */
 633             bq->read_index += (int64_t) length;
 634             break;
 635         }
 636     }
 637
 638     drop_backlog(bq);
 639     read_index_changed(bq, old);
 640 }
 641
 642 void pa_memblockq_rewind(pa_memblockq *bq, size_t length) {
 643     int64_t old;
 644     pa_assert(bq);
 645     pa_assert(length % bq->base == 0);
 646
 647     old = bq->read_index;
 648
 649     /* This is kind of the inverse of pa_memblockq_drop() */
 650
 651     bq->read_index -= (int64_t) length;
 652
 653     read_index_changed(bq, old);
 654 }
 655
 656 pa_bool_t pa_memblockq_is_readable(pa_memblockq *bq) {
 657     pa_assert(bq);
 658
 659     if (pa_memblockq_prebuf_active(bq))
 660         return FALSE;
 661
 662     if (pa_memblockq_get_length(bq) <= 0)
 663         return FALSE;
 664
 665     return TRUE;
 666 }
 667
 668 size_t pa_memblockq_get_length(pa_memblockq *bq) {
 669     pa_assert(bq);
 670
 671     if (bq->write_index <= bq->read_index)
 672         return 0;
 673
 674     return (size_t) (bq->write_index - bq->read_index);
 675 }
 676
 677 size_t pa_memblockq_missing(pa_memblockq *bq) {
 678     size_t l;
 679     pa_assert(bq);
 680
 681     if ((l = pa_memblockq_get_length(bq)) >= bq->tlength)
 682         return 0;
 683
 684     l = bq->tlength - l;
 685
 686     return l >= bq->minreq ? l : 0;
 687 }
 688
 689 void pa_memblockq_seek(pa_memblockq *bq, int64_t offset, pa_seek_mode_t seek, pa_bool_t account) {
 690     int64_t old;
 691     pa_assert(bq);
 692
 693     old = bq->write_index;
 694
 695     switch (seek) {
 696         case PA_SEEK_RELATIVE:
 697             bq->write_index += offset;
 698             break;
 699         case PA_SEEK_ABSOLUTE:
 700             bq->write_index = offset;
 701             break;
 702         case PA_SEEK_RELATIVE_ON_READ:
 703             bq->write_index = bq->read_index + offset;
 704             break;
 705         case PA_SEEK_RELATIVE_END:
 706             bq->write_index = (bq->blocks_tail ? bq->blocks_tail->index + (int64_t) bq->blocks_tail->chunk.length : bq->read_index) + offset;
 707             break;
 708         default:
 709             pa_assert_not_reached();
 710     }
 711
 712     drop_backlog(bq);
 713     write_index_changed(bq, old, account);
 714 }
 715
 716 void pa_memblockq_flush_write(pa_memblockq *bq, pa_bool_t account) {
 717     int64_t old;
 718     pa_assert(bq);
 719
 720     pa_memblockq_silence(bq);
 721
 722     old = bq->write_index;
 723     bq->write_index = bq->read_index;
 724
 725     pa_memblockq_prebuf_force(bq);
 726     write_index_changed(bq, old, account);
 727 }
 728
 729 void pa_memblockq_flush_read(pa_memblockq *bq) {
 730     int64_t old;
 731     pa_assert(bq);
 732
 733     pa_memblockq_silence(bq);
 734
 735     old = bq->read_index;
 736     bq->read_index = bq->write_index;
 737
 738     pa_memblockq_prebuf_force(bq);
 739     read_index_changed(bq, old);
 740 }
 741
 742 size_t pa_memblockq_get_tlength(pa_memblockq *bq) {
 743     pa_assert(bq);
 744
 745     return bq->tlength;
 746 }
 747
 748 size_t pa_memblockq_get_minreq(pa_memblockq *bq) {
 749     pa_assert(bq);
 750
 751     return bq->minreq;
 752 }
 753
 754 size_t pa_memblockq_get_maxrewind(pa_memblockq *bq) {
 755     pa_assert(bq);
 756
 757     return bq->maxrewind;
 758 }
 759
 760 int64_t pa_memblockq_get_read_index(pa_memblockq *bq) {
 761     pa_assert(bq);
 762
 763     return bq->read_index;
 764 }
 765
 766 int64_t pa_memblockq_get_write_index(pa_memblockq *bq) {
 767     pa_assert(bq);
 768
 769     return bq->write_index;
 770 }
 771
 772 int pa_memblockq_push_align(pa_memblockq* bq, const pa_memchunk *chunk) {
 773     pa_memchunk rchunk;
 774
 775     pa_assert(bq);
 776     pa_assert(chunk);
 777
 778     if (bq->base == 1)
 779         return pa_memblockq_push(bq, chunk);
 780
 781     if (!can_push(bq, pa_mcalign_csize(bq->mcalign, chunk->length)))
 782         return -1;
 783
 784     pa_mcalign_push(bq->mcalign, chunk);
 785
 786     while (pa_mcalign_pop(bq->mcalign, &rchunk) >= 0) {
 787         int r;
 788         r = pa_memblockq_push(bq, &rchunk);
 789         pa_memblock_unref(rchunk.memblock);
 790
 791         if (r < 0) {
 792             pa_mcalign_flush(bq->mcalign);
 793             return -1;
 794         }
 795     }
 796
 797     return 0;
 798 }
 799
 800 void pa_memblockq_prebuf_disable(pa_memblockq *bq) {
 801     pa_assert(bq);
 802
 803     bq->in_prebuf = FALSE;
 804 }
 805
 806 void pa_memblockq_prebuf_force(pa_memblockq *bq) {
 807     pa_assert(bq);
 808
 809     if (bq->prebuf > 0)
 810         bq->in_prebuf = TRUE;
 811 }
 812
 813 size_t pa_memblockq_get_maxlength(pa_memblockq *bq) {
 814     pa_assert(bq);
 815
 816     return bq->maxlength;
 817 }
 818
 819 size_t pa_memblockq_get_prebuf(pa_memblockq *bq) {
 820     pa_assert(bq);
 821
 822     return bq->prebuf;
 823 }
 824
 825 size_t pa_memblockq_pop_missing(pa_memblockq *bq) {
 826     size_t l;
 827
 828     pa_assert(bq);
 829
 830 /*     pa_log("pop: %lli", bq->missing); */
 831
 832     if (bq->missing <= 0)
 833         return 0;
 834
 835     l = (size_t) bq->missing;
 836
 837     bq->requested += bq->missing;
 838     bq->missing = 0;
 839
 840     /* pa_log("sent %lli: request counter is at %lli", (long long) l, (long long) bq->requested); */
 841
 842     return l;
 843 }
 844
 845 void pa_memblockq_set_maxlength(pa_memblockq *bq, size_t maxlength) {
 846     pa_assert(bq);
 847
 848     bq->maxlength = ((maxlength+bq->base-1)/bq->base)*bq->base;
 849
 850     if (bq->maxlength < bq->base)
 851         bq->maxlength = bq->base;
 852
 853     if (bq->tlength > bq->maxlength)
 854         pa_memblockq_set_tlength(bq, bq->maxlength);
 855 }
 856
 857 void pa_memblockq_set_tlength(pa_memblockq *bq, size_t tlength) {
 858     size_t old_tlength;
 859     pa_assert(bq);
 860
 861     if (tlength <= 0 || tlength == (size_t) -1)
 862         tlength = bq->maxlength;
 863
 864     old_tlength = bq->tlength;
 865     bq->tlength = ((tlength+bq->base-1)/bq->base)*bq->base;
 866
 867     if (bq->tlength > bq->maxlength)
 868         bq->tlength = bq->maxlength;
 869
 870     if (bq->minreq > bq->tlength)
 871         pa_memblockq_set_minreq(bq, bq->tlength);
 872
 873     if (bq->prebuf > bq->tlength+bq->base-bq->minreq)
 874         pa_memblockq_set_prebuf(bq, bq->tlength+bq->base-bq->minreq);
 875
 876     bq->missing += (int64_t) bq->tlength - (int64_t) old_tlength;
 877 }
 878
 879 void pa_memblockq_set_minreq(pa_memblockq *bq, size_t minreq) {
 880     pa_assert(bq);
 881
 882     bq->minreq = (minreq/bq->base)*bq->base;
 883
 884     if (bq->minreq > bq->tlength)
 885         bq->minreq = bq->tlength;
 886
 887     if (bq->minreq < bq->base)
 888         bq->minreq = bq->base;
 889
 890     if (bq->prebuf > bq->tlength+bq->base-bq->minreq)
 891         pa_memblockq_set_prebuf(bq, bq->tlength+bq->base-bq->minreq);
 892 }
 893
 894 void pa_memblockq_set_prebuf(pa_memblockq *bq, size_t prebuf) {
 895     pa_assert(bq);
 896
 897     if (prebuf == (size_t) -1)
 898         prebuf = bq->tlength+bq->base-bq->minreq;
 899
 900     bq->prebuf = ((prebuf+bq->base-1)/bq->base)*bq->base;
 901
 902     if (prebuf > 0 && bq->prebuf < bq->base)
 903         bq->prebuf = bq->base;
 904
 905     if (bq->prebuf > bq->tlength+bq->base-bq->minreq)
 906         bq->prebuf = bq->tlength+bq->base-bq->minreq;
 907
 908     if (bq->prebuf <= 0 || pa_memblockq_get_length(bq) >= bq->prebuf)
 909         bq->in_prebuf = FALSE;
 910 }
 911
 912 void pa_memblockq_set_maxrewind(pa_memblockq *bq, size_t maxrewind) {
 913     pa_assert(bq);
 914
 915     bq->maxrewind = (maxrewind/bq->base)*bq->base;
 916 }
 917
 918 void pa_memblockq_apply_attr(pa_memblockq *bq, const pa_buffer_attr *a) {
 919     pa_assert(bq);
 920     pa_assert(a);
 921
 922     pa_memblockq_set_maxlength(bq, a->maxlength);
 923     pa_memblockq_set_tlength(bq, a->tlength);
 924     pa_memblockq_set_prebuf(bq, a->prebuf);
 925     pa_memblockq_set_minreq(bq, a->minreq);
 926 }
 927
 928 void pa_memblockq_get_attr(pa_memblockq *bq, pa_buffer_attr *a) {
 929     pa_assert(bq);
 930     pa_assert(a);
 931
 932     a->maxlength = (uint32_t) pa_memblockq_get_maxlength(bq);
 933     a->tlength = (uint32_t) pa_memblockq_get_tlength(bq);
 934     a->prebuf = (uint32_t) pa_memblockq_get_prebuf(bq);
 935     a->minreq = (uint32_t) pa_memblockq_get_minreq(bq);
 936 }
 937
 938 int pa_memblockq_splice(pa_memblockq *bq, pa_memblockq *source) {
 939
 940     pa_assert(bq);
 941     pa_assert(source);
 942
 943     pa_memblockq_prebuf_disable(bq);
 944
 945     for (;;) {
 946         pa_memchunk chunk;
 947
 948         if (pa_memblockq_peek(source, &chunk) < 0)
 949             return 0;
 950
 951         pa_assert(chunk.length > 0);
 952
 953         if (chunk.memblock) {
 954
 955             if (pa_memblockq_push_align(bq, &chunk) < 0) {
 956                 pa_memblock_unref(chunk.memblock);
 957                 return -1;
 958             }
 959
 960             pa_memblock_unref(chunk.memblock);
 961         } else
 962             pa_memblockq_seek(bq, (int64_t) chunk.length, PA_SEEK_RELATIVE, TRUE);
 963
 964         pa_memblockq_drop(bq, chunk.length);
 965     }
 966 }
 967
 968 void pa_memblockq_willneed(pa_memblockq *bq) {
 969     struct list_item *q;
 970
 971     pa_assert(bq);
 972
 973     fix_current_read(bq);
 974
 975     for (q = bq->current_read; q; q = q->next)
 976         pa_memchunk_will_need(&q->chunk);
 977 }
 978
 979 void pa_memblockq_set_silence(pa_memblockq *bq, pa_memchunk *silence) {
 980     pa_assert(bq);
 981
 982     if (bq->silence.memblock)
 983         pa_memblock_unref(bq->silence.memblock);
 984
 985     if (silence) {
 986         bq->silence = *silence;
 987         pa_memblock_ref(bq->silence.memblock);
 988     } else
 989         pa_memchunk_reset(&bq->silence);
 990 }
 991
 992 pa_bool_t pa_memblockq_is_empty(pa_memblockq *bq) {
 993     pa_assert(bq);
 994
 995     return !bq->blocks;
 996 }
 997
 998 void pa_memblockq_silence(pa_memblockq *bq) {
 999     pa_assert(bq);
1000
1001     while (bq->blocks)
1002         drop_block(bq, bq->blocks);
1003
1004     pa_assert(bq->n_blocks == 0);
1005 }
1006
1007 unsigned pa_memblockq_get_nblocks(pa_memblockq *bq) {
1008     pa_assert(bq);
1009
1010     return bq->n_blocks;
1011 }
1012
1013 size_t pa_memblockq_get_base(pa_memblockq *bq) {
1014     pa_assert(bq);
1015
1016     return bq->base;
1017 }