src/pulsecore/memblockq.c

   1 /* $Id$ */
   2
   3 /***
   4   This file is part of PulseAudio.
   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 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 <assert.h>
  30 #include <stdlib.h>
  31 #include <string.h>
  32
  33 #include <pulse/xmalloc.h>
  34
  35 #include <pulsecore/log.h>
  36 #include <pulsecore/mcalign.h>
  37
  38 #include "memblockq.h"
  39
  40 struct memblock_list {
  41     struct memblock_list *next, *prev;
  42     int64_t index;
  43     pa_memchunk chunk;
  44 };
  45
  46 struct pa_memblockq {
  47     struct memblock_list *blocks, *blocks_tail;
  48     unsigned n_blocks;
  49     size_t maxlength, tlength, base, prebuf, minreq;
  50     int64_t read_index, write_index;
  51     enum { PREBUF, RUNNING } state;
  52     pa_memblock *silence;
  53     pa_mcalign *mcalign;
  54 };
  55
  56 pa_memblockq* pa_memblockq_new(
  57         int64_t idx,
  58         size_t maxlength,
  59         size_t tlength,
  60         size_t base,
  61         size_t prebuf,
  62         size_t minreq,
  63         pa_memblock *silence) {
  64
  65     pa_memblockq* bq;
  66
  67     assert(base > 0);
  68     assert(maxlength >= base);
  69
  70     bq = pa_xnew(pa_memblockq, 1);
  71     bq->blocks = bq->blocks_tail = NULL;
  72     bq->n_blocks = 0;
  73
  74     bq->base = base;
  75     bq->read_index = bq->write_index = idx;
  76
  77     pa_log_debug("memblockq requested: maxlength=%lu, tlength=%lu, base=%lu, prebuf=%lu, minreq=%lu",
  78         (unsigned long)maxlength, (unsigned long)tlength, (unsigned long)base, (unsigned long)prebuf, (unsigned long)minreq);
  79
  80     bq->maxlength = ((maxlength+base-1)/base)*base;
  81     assert(bq->maxlength >= base);
  82
  83     bq->tlength = ((tlength+base-1)/base)*base;
  84     if (!bq->tlength || bq->tlength >= bq->maxlength)
  85         bq->tlength = bq->maxlength;
  86
  87     bq->prebuf = (prebuf == (size_t) -1) ? bq->tlength/2 : prebuf;
  88     bq->prebuf = ((bq->prebuf+base-1)/base)*base;
  89     if (bq->prebuf > bq->maxlength)
  90         bq->prebuf = bq->maxlength;
  91
  92     bq->minreq = (minreq/base)*base;
  93
  94     if (bq->minreq > bq->tlength - bq->prebuf)
  95         bq->minreq = bq->tlength - bq->prebuf;
  96
  97     if (!bq->minreq)
  98         bq->minreq = 1;
  99
 100     pa_log_debug("memblockq sanitized: maxlength=%lu, tlength=%lu, base=%lu, prebuf=%lu, minreq=%lu",
 101         (unsigned long)bq->maxlength, (unsigned long)bq->tlength, (unsigned long)bq->base, (unsigned long)bq->prebuf, (unsigned long)bq->minreq);
 102
 103     bq->state = bq->prebuf ? PREBUF : RUNNING;
 104     bq->silence = silence ? pa_memblock_ref(silence) : NULL;
 105     bq->mcalign = NULL;
 106
 107     return bq;
 108 }
 109
 110 void pa_memblockq_free(pa_memblockq* bq) {
 111     assert(bq);
 112
 113     pa_memblockq_flush(bq);
 114
 115     if (bq->silence)
 116         pa_memblock_unref(bq->silence);
 117
 118     if (bq->mcalign)
 119         pa_mcalign_free(bq->mcalign);
 120
 121     pa_xfree(bq);
 122 }
 123
 124 static void drop_block(pa_memblockq *bq, struct memblock_list *q) {
 125     assert(bq);
 126     assert(q);
 127
 128     assert(bq->n_blocks >= 1);
 129
 130     if (q->prev)
 131         q->prev->next = q->next;
 132     else
 133         bq->blocks = q->next;
 134
 135     if (q->next)
 136         q->next->prev = q->prev;
 137     else
 138         bq->blocks_tail = q->prev;
 139
 140     pa_memblock_unref(q->chunk.memblock);
 141     pa_xfree(q);
 142
 143     bq->n_blocks--;
 144 }
 145
 146 static int can_push(pa_memblockq *bq, size_t l) {
 147     int64_t end;
 148
 149     assert(bq);
 150
 151     if (bq->read_index > bq->write_index) {
 152         size_t d =  bq->read_index - bq->write_index;
 153
 154         if (l > d)
 155             l -= d;
 156         else
 157             return 1;
 158     }
 159
 160     end = bq->blocks_tail ? bq->blocks_tail->index + bq->blocks_tail->chunk.length : 0;
 161
 162     /* Make sure that the list doesn't get too long */
 163     if (bq->write_index + (int64_t)l > end)
 164         if (bq->write_index + l - bq->read_index > bq->maxlength)
 165             return 0;
 166
 167     return 1;
 168 }
 169
 170 int pa_memblockq_push(pa_memblockq* bq, const pa_memchunk *uchunk) {
 171
 172     struct memblock_list *q, *n;
 173     pa_memchunk chunk;
 174
 175     assert(bq);
 176     assert(uchunk);
 177     assert(uchunk->memblock);
 178     assert(uchunk->length > 0);
 179     assert(uchunk->index + uchunk->length <= uchunk->memblock->length);
 180
 181     if (uchunk->length % bq->base)
 182         return -1;
 183
 184     if (!can_push(bq, uchunk->length))
 185         return -1;
 186
 187     chunk = *uchunk;
 188
 189     if (bq->read_index > bq->write_index) {
 190
 191         /* We currently have a buffer underflow, we need to drop some
 192          * incoming data */
 193
 194         size_t d = bq->read_index - bq->write_index;
 195
 196         if (chunk.length > d) {
 197             chunk.index += d;
 198             chunk.length -= d;
 199             bq->write_index = bq->read_index;
 200         } else {
 201             /* We drop the incoming data completely */
 202             bq->write_index += chunk.length;
 203             return 0;
 204         }
 205     }
 206
 207     /* We go from back to front to look for the right place to add
 208      * this new entry. Drop data we will overwrite on the way */
 209
 210     q = bq->blocks_tail;
 211     while (q) {
 212
 213         if (bq->write_index >= q->index + (int64_t)q->chunk.length)
 214             /* We found the entry where we need to place the new entry immediately after */
 215             break;
 216         else if (bq->write_index + (int64_t)chunk.length <= q->index) {
 217             /* This entry isn't touched at all, let's skip it */
 218             q = q->prev;
 219         } else if (bq->write_index <= q->index &&
 220             bq->write_index + chunk.length >= q->index + q->chunk.length) {
 221
 222             /* This entry is fully replaced by the new entry, so let's drop it */
 223
 224             struct memblock_list *p;
 225             p = q;
 226             q = q->prev;
 227             drop_block(bq, p);
 228         } else if (bq->write_index >= q->index) {
 229             /* The write index points into this memblock, so let's
 230              * truncate or split it */
 231
 232             if (bq->write_index + chunk.length < q->index + q->chunk.length) {
 233
 234                 /* We need to save the end of this memchunk */
 235                 struct memblock_list *p;
 236                 size_t d;
 237
 238                 /* Create a new list entry for the end of thie memchunk */
 239                 p = pa_xnew(struct memblock_list, 1);
 240                 p->chunk = q->chunk;
 241                 pa_memblock_ref(p->chunk.memblock);
 242
 243                 /* Calculate offset */
 244                 d = bq->write_index + chunk.length - q->index;
 245                 assert(d > 0);
 246
 247                 /* Drop it from the new entry */
 248                 p->index = q->index + d;
 249                 p->chunk.length -= d;
 250
 251                 /* Add it to the list */
 252                 p->prev = q;
 253                 if ((p->next = q->next))
 254                     q->next->prev = p;
 255                 else
 256                     bq->blocks_tail = p;
 257                 q->next = p;
 258
 259                 bq->n_blocks++;
 260             }
 261
 262             /* Truncate the chunk */
 263             if (!(q->chunk.length = bq->write_index - q->index)) {
 264                 struct memblock_list *p;
 265                 p = q;
 266                 q = q->prev;
 267                 drop_block(bq, p);
 268             }
 269
 270             /* We had to truncate this block, hence we're now at the right position */
 271             break;
 272         } else {
 273             size_t d;
 274
 275             assert(bq->write_index + (int64_t)chunk.length > q->index &&
 276                    bq->write_index + (int64_t)chunk.length < q->index + (int64_t)q->chunk.length &&
 277                    bq->write_index < q->index);
 278
 279             /* The job overwrites the current entry at the end, so let's drop the beginning of this entry */
 280
 281             d = bq->write_index + chunk.length - q->index;
 282             q->index += d;
 283             q->chunk.index += d;
 284             q->chunk.length -= d;
 285
 286             q = q->prev;
 287         }
 288
 289     }
 290
 291     if (q) {
 292         assert(bq->write_index >=  q->index + (int64_t)q->chunk.length);
 293         assert(!q->next || (bq->write_index + (int64_t)chunk.length <= q->next->index));
 294
 295         /* Try to merge memory blocks */
 296
 297         if (q->chunk.memblock == chunk.memblock &&
 298             q->chunk.index + (int64_t)q->chunk.length == chunk.index &&
 299             bq->write_index == q->index + (int64_t)q->chunk.length) {
 300
 301             q->chunk.length += chunk.length;
 302             bq->write_index += chunk.length;
 303             return 0;
 304         }
 305     } else
 306         assert(!bq->blocks || (bq->write_index + (int64_t)chunk.length <= bq->blocks->index));
 307
 308
 309     n = pa_xnew(struct memblock_list, 1);
 310     n->chunk = chunk;
 311     pa_memblock_ref(n->chunk.memblock);
 312     n->index = bq->write_index;
 313     bq->write_index += n->chunk.length;
 314
 315     n->next = q ? q->next : bq->blocks;
 316     n->prev = q;
 317
 318     if (n->next)
 319         n->next->prev = n;
 320     else
 321         bq->blocks_tail = n;
 322
 323     if (n->prev)
 324         n->prev->next = n;
 325     else
 326         bq->blocks = n;
 327
 328     bq->n_blocks++;
 329     return 0;
 330 }
 331
 332 int pa_memblockq_peek(pa_memblockq* bq, pa_memchunk *chunk) {
 333     assert(bq);
 334     assert(chunk);
 335
 336     if (bq->state == PREBUF) {
 337
 338         /* We need to pre-buffer */
 339         if (pa_memblockq_get_length(bq) < bq->prebuf)
 340             return -1;
 341
 342         bq->state = RUNNING;
 343
 344     } else if (bq->prebuf > 0 && bq->read_index >= bq->write_index) {
 345
 346         /* Buffer underflow protection */
 347         bq->state = PREBUF;
 348         return -1;
 349     }
 350
 351     /* Do we need to spit out silence? */
 352     if (!bq->blocks || bq->blocks->index > bq->read_index) {
 353
 354         size_t length;
 355
 356         /* How much silence shall we return? */
 357         length = bq->blocks ? bq->blocks->index - bq->read_index : 0;
 358
 359         /* We need to return silence, since no data is yet available */
 360         if (bq->silence) {
 361             chunk->memblock = pa_memblock_ref(bq->silence);
 362
 363             if (!length || length > chunk->memblock->length)
 364                 length = chunk->memblock->length;
 365
 366             chunk->length = length;
 367         } else {
 368
 369             /* If the memblockq is empty, return -1, otherwise return
 370              * the time to sleep */
 371             if (!bq->blocks)
 372                 return -1;
 373
 374             chunk->memblock = NULL;
 375             chunk->length = length;
 376         }
 377
 378         chunk->index = 0;
 379         return 0;
 380     }
 381
 382     /* Ok, let's pass real data to the caller */
 383     assert(bq->blocks->index == bq->read_index);
 384
 385     *chunk = bq->blocks->chunk;
 386     pa_memblock_ref(chunk->memblock);
 387
 388     return 0;
 389 }
 390
 391 void pa_memblockq_drop(pa_memblockq *bq, const pa_memchunk *chunk, size_t length) {
 392     assert(bq);
 393     assert(length % bq->base == 0);
 394
 395     assert(!chunk || length <= chunk->length);
 396
 397     if (chunk) {
 398
 399         if (bq->blocks && bq->blocks->index == bq->read_index) {
 400             /* The first item in queue is valid */
 401
 402             /* Does the chunk match with what the user supplied us? */
 403             if (memcmp(chunk, &bq->blocks->chunk, sizeof(pa_memchunk)) != 0)
 404                 return;
 405
 406         } else {
 407             size_t l;
 408
 409             /* The first item in the queue is not yet relevant */
 410
 411             assert(!bq->blocks || bq->blocks->index > bq->read_index);
 412             l = bq->blocks ? bq->blocks->index - bq->read_index : 0;
 413
 414             if (bq->silence) {
 415
 416                 if (!l || l > bq->silence->length)
 417                     l = bq->silence->length;
 418
 419             }
 420
 421             /* Do the entries still match? */
 422             if (chunk->index != 0 || chunk->length != l || chunk->memblock != bq->silence)
 423                 return;
 424         }
 425     }
 426
 427     while (length > 0) {
 428
 429         if (bq->blocks) {
 430             size_t d;
 431
 432             assert(bq->blocks->index >= bq->read_index);
 433
 434             d = (size_t) (bq->blocks->index - bq->read_index);
 435
 436             if (d >= length) {
 437                 /* The first block is too far in the future */
 438
 439                 bq->read_index += length;
 440                 break;
 441             } else {
 442
 443                 length -= d;
 444                 bq->read_index += d;
 445             }
 446
 447             assert(bq->blocks->index == bq->read_index);
 448
 449             if (bq->blocks->chunk.length <= length) {
 450                 /* We need to drop the full block */
 451
 452                 length -= bq->blocks->chunk.length;
 453                 bq->read_index += bq->blocks->chunk.length;
 454
 455                 drop_block(bq, bq->blocks);
 456             } else {
 457                 /* Only the start of this block needs to be dropped */
 458
 459                 bq->blocks->chunk.index += length;
 460                 bq->blocks->chunk.length -= length;
 461                 bq->blocks->index += length;
 462                 bq->read_index += length;
 463                 break;
 464             }
 465
 466         } else {
 467
 468             /* The list is empty, there's nothing we could drop */
 469             bq->read_index += length;
 470             break;
 471         }
 472     }
 473 }
 474
 475 int pa_memblockq_is_readable(pa_memblockq *bq) {
 476     assert(bq);
 477
 478     if (bq->prebuf > 0) {
 479         size_t l = pa_memblockq_get_length(bq);
 480
 481         if (bq->state == PREBUF && l < bq->prebuf)
 482             return 0;
 483
 484         if (l <= 0)
 485             return 0;
 486     }
 487
 488     return 1;
 489 }
 490
 491 int pa_memblockq_is_writable(pa_memblockq *bq, size_t length) {
 492     assert(bq);
 493
 494     if (length % bq->base)
 495         return 0;
 496
 497     return pa_memblockq_get_length(bq) + length <= bq->tlength;
 498 }
 499
 500 size_t pa_memblockq_get_length(pa_memblockq *bq) {
 501     assert(bq);
 502
 503     if (bq->write_index <= bq->read_index)
 504         return 0;
 505
 506     return (size_t) (bq->write_index - bq->read_index);
 507 }
 508
 509 size_t pa_memblockq_missing(pa_memblockq *bq) {
 510     size_t l;
 511     assert(bq);
 512
 513     if ((l = pa_memblockq_get_length(bq)) >= bq->tlength)
 514         return 0;
 515
 516     l = bq->tlength - l;
 517     return (l >= bq->minreq) ? l : 0;
 518 }
 519
 520 size_t pa_memblockq_get_minreq(pa_memblockq *bq) {
 521     assert(bq);
 522
 523     return bq->minreq;
 524 }
 525
 526 void pa_memblockq_seek(pa_memblockq *bq, int64_t offset, pa_seek_mode_t seek) {
 527     assert(bq);
 528
 529     switch (seek) {
 530         case PA_SEEK_RELATIVE:
 531             bq->write_index += offset;
 532             return;
 533         case PA_SEEK_ABSOLUTE:
 534             bq->write_index = offset;
 535             return;
 536         case PA_SEEK_RELATIVE_ON_READ:
 537             bq->write_index = bq->read_index + offset;
 538             return;
 539         case PA_SEEK_RELATIVE_END:
 540             bq->write_index = (bq->blocks_tail ? bq->blocks_tail->index + (int64_t)bq->blocks_tail->chunk.length : bq->read_index) + offset;
 541             return;
 542     }
 543
 544     assert(0);
 545 }
 546
 547 void pa_memblockq_flush(pa_memblockq *bq) {
 548     assert(bq);
 549
 550     while (bq->blocks)
 551         drop_block(bq, bq->blocks);
 552
 553     assert(bq->n_blocks == 0);
 554
 555     bq->write_index = bq->read_index;
 556
 557     pa_memblockq_prebuf_force(bq);
 558 }
 559
 560 size_t pa_memblockq_get_tlength(pa_memblockq *bq) {
 561     assert(bq);
 562
 563     return bq->tlength;
 564 }
 565
 566 int64_t pa_memblockq_get_read_index(pa_memblockq *bq) {
 567     assert(bq);
 568     return bq->read_index;
 569 }
 570
 571 int64_t pa_memblockq_get_write_index(pa_memblockq *bq) {
 572     assert(bq);
 573     return bq->write_index;
 574 }
 575
 576 int pa_memblockq_push_align(pa_memblockq* bq, const pa_memchunk *chunk) {
 577     pa_memchunk rchunk;
 578
 579     assert(bq);
 580     assert(chunk && bq->base);
 581
 582     if (bq->base == 1)
 583         return pa_memblockq_push(bq, chunk);
 584
 585     if (!bq->mcalign)
 586         bq->mcalign = pa_mcalign_new(bq->base);
 587
 588     if (!can_push(bq, pa_mcalign_csize(bq->mcalign, chunk->length)))
 589         return -1;
 590
 591     pa_mcalign_push(bq->mcalign, chunk);
 592
 593     while (pa_mcalign_pop(bq->mcalign, &rchunk) >= 0) {
 594         int r;
 595         r = pa_memblockq_push(bq, &rchunk);
 596         pa_memblock_unref(rchunk.memblock);
 597
 598         if (r < 0)
 599             return -1;
 600     }
 601
 602     return 0;
 603 }
 604
 605 void pa_memblockq_shorten(pa_memblockq *bq, size_t length) {
 606     size_t l;
 607     assert(bq);
 608
 609     l = pa_memblockq_get_length(bq);
 610
 611     if (l > length)
 612         pa_memblockq_drop(bq, NULL, l - length);
 613 }
 614
 615 void pa_memblockq_prebuf_disable(pa_memblockq *bq) {
 616     assert(bq);
 617
 618     if (bq->state == PREBUF)
 619         bq->state = RUNNING;
 620 }
 621
 622 void pa_memblockq_prebuf_force(pa_memblockq *bq) {
 623     assert(bq);
 624
 625     if (bq->state == RUNNING && bq->prebuf > 0)
 626         bq->state = PREBUF;
 627 }
 628
 629 size_t pa_memblockq_get_maxlength(pa_memblockq *bq) {
 630     assert(bq);
 631
 632     return bq->maxlength;
 633 }
 634
 635 size_t pa_memblockq_get_prebuf(pa_memblockq *bq) {
 636     assert(bq);
 637
 638     return bq->prebuf;
 639 }