stream/cache2.c

   1 /*
   2  * This file is part of MPlayer.
   3  *
   4  * MPlayer is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * MPlayer is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #include "config.h"
  20
  21 // Initial draft of my new cache system...
  22 // Note it runs in 2 processes (using fork()), but doesn't require locking!!
  23 // TODO: seeking, data consistency checking
  24
  25 #define READ_SLEEP_TIME 10
  26 // These defines are used to reduce the cost of many successive
  27 // seeks (e.g. when a file has no index) by spinning quickly at first.
  28 #define INITIAL_FILL_USLEEP_TIME 1000
  29 #define INITIAL_FILL_USLEEP_COUNT 10
  30 #define FILL_USLEEP_TIME 50000
  31 #define PREFILL_SLEEP_TIME 200
  32 #define CONTROL_SLEEP_TIME 0
  33
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <signal.h>
  38 #include <sys/types.h>
  39 #include <unistd.h>
  40 #include <errno.h>
  41
  42 #include "libavutil/avutil.h"
  43 #include "osdep/shmem.h"
  44 #include "osdep/timer.h"
  45 #if defined(__MINGW32__)
  46 #include <windows.h>
  47 static void ThreadProc( void *s );
  48 #elif defined(__OS2__)
  49 #define INCL_DOS
  50 #include <os2.h>
  51 static void ThreadProc( void *s );
  52 #elif defined(PTHREAD_CACHE)
  53 #include <pthread.h>
  54 static void *ThreadProc(void *s);
  55 #else
  56 #include <sys/wait.h>
  57 #define FORKED_CACHE 1
  58 #endif
  59 #ifndef FORKED_CACHE
  60 #define FORKED_CACHE 0
  61 #endif
  62
  63 #include "mp_msg.h"
  64
  65 #include "stream.h"
  66 #include "cache2.h"
  67
  68 typedef struct {
  69   // constats:
  70   unsigned char *buffer;      // base pointer of the allocated buffer memory
  71   int buffer_size; // size of the allocated buffer memory
  72   int sector_size; // size of a single sector (2048/2324)
  73   int back_size;   // we should keep back_size amount of old bytes for backward seek
  74   int fill_limit;  // we should fill buffer only if space>=fill_limit
  75   int seek_limit;  // keep filling cache if distance is less that seek limit
  76   // filler's pointers:
  77   int eof;
  78   off_t min_filepos; // buffer contain only a part of the file, from min-max pos
  79   off_t max_filepos;
  80   off_t offset;      // filepos <-> bufferpos  offset value (filepos of the buffer's first byte)
  81   // reader's pointers:
  82   off_t read_filepos;
  83   // commands/locking:
  84 //  int seek_lock;   // 1 if we will seek/reset buffer, 2 if we are ready for cmd
  85 //  int fifo_flag;  // 1 if we should use FIFO to notice cache about buffer reads.
  86   // callback
  87   stream_t* stream;
  88   volatile int control;
  89   volatile unsigned control_uint_arg;
  90   volatile double control_double_arg;
  91   volatile int control_res;
  92   volatile off_t control_new_pos;
  93   volatile double stream_time_length;
  94 } cache_vars_t;
  95
  96 static int min_fill=0;
  97
  98 static void cache_wakeup(stream_t *s)
  99 {
 100 #if FORKED_CACHE
 101   // signal process to wake up immediately
 102   kill(s->cache_pid, SIGUSR1);
 103 #endif
 104 }
 105
 106 static int cache_read(cache_vars_t *s, unsigned char *buf, int size)
 107 {
 108   int total=0;
 109   int sleep_count = 0;
 110   int last_max = s->max_filepos;
 111   while(size>0){
 112     int pos,newb,len;
 113
 114   //printf("CACHE2_READ: 0x%X <= 0x%X <= 0x%X  \n",s->min_filepos,s->read_filepos,s->max_filepos);
 115
 116     if(s->read_filepos>=s->max_filepos || s->read_filepos<s->min_filepos){
 117         // eof?
 118         if(s->eof) break;
 119         if (s->max_filepos == last_max) {
 120             if (sleep_count++ == 10)
 121                 mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not filling, consider increasing -cache and/or -cache-min!\n");
 122         } else {
 123             last_max = s->max_filepos;
 124             sleep_count = 0;
 125         }
 126         // waiting for buffer fill...
 127         if (stream_check_interrupt(READ_SLEEP_TIME)) {
 128             s->eof = 1;
 129             break;
 130         }
 131         continue; // try again...
 132     }
 133     sleep_count = 0;
 134
 135     newb=s->max_filepos-s->read_filepos; // new bytes in the buffer
 136     if(newb<min_fill) min_fill=newb; // statistics...
 137
 138 //    printf("*** newb: %d bytes ***\n",newb);
 139
 140     pos=s->read_filepos - s->offset;
 141     if(pos<0) pos+=s->buffer_size; else
 142     if(pos>=s->buffer_size) pos-=s->buffer_size;
 143
 144     if(newb>s->buffer_size-pos) newb=s->buffer_size-pos; // handle wrap...
 145     if(newb>size) newb=size;
 146
 147     // check:
 148     if(s->read_filepos<s->min_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"Ehh. s->read_filepos<s->min_filepos !!! Report bug...\n");
 149
 150     // len=write(mem,newb)
 151     //printf("Buffer read: %d bytes\n",newb);
 152     memcpy(buf,&s->buffer[pos],newb);
 153     buf+=newb;
 154     len=newb;
 155     // ...
 156
 157     s->read_filepos+=len;
 158     size-=len;
 159     total+=len;
 160
 161   }
 162   return total;
 163 }
 164
 165 static int cache_fill(cache_vars_t *s)
 166 {
 167   int back,back2,newb,space,len,pos;
 168   off_t read=s->read_filepos;
 169   int read_chunk;
 170   int wraparound_copy = 0;
 171
 172   if(read<s->min_filepos || read>s->max_filepos){
 173       // seek...
 174       mp_msg(MSGT_CACHE,MSGL_DBG2,"Out of boundaries... seeking to 0x%"PRIX64"  \n",(int64_t)read);
 175       // drop cache contents only if seeking backward or too much fwd.
 176       // This is also done for on-disk files, since it loses the backseek cache.
 177       // That in turn can cause major bandwidth increase and performance
 178       // issues with e.g. mov or badly interleaved files
 179       if(read<s->min_filepos || read>=s->max_filepos+s->seek_limit)
 180       {
 181         s->offset= // FIXME!?
 182         s->min_filepos=s->max_filepos=read; // drop cache content :(
 183         if(s->stream->eof) stream_reset(s->stream);
 184         stream_seek_internal(s->stream,read);
 185         mp_msg(MSGT_CACHE,MSGL_DBG2,"Seek done. new pos: 0x%"PRIX64"  \n",(int64_t)stream_tell(s->stream));
 186       }
 187   }
 188
 189   // calc number of back-bytes:
 190   back=read - s->min_filepos;
 191   if(back<0) back=0; // strange...
 192   if(back>s->back_size) back=s->back_size;
 193
 194   // calc number of new bytes:
 195   newb=s->max_filepos - read;
 196   if(newb<0) newb=0; // strange...
 197
 198   // calc free buffer space:
 199   space=s->buffer_size - (newb+back);
 200
 201   // calc bufferpos:
 202   pos=s->max_filepos - s->offset;
 203   if(pos>=s->buffer_size) pos-=s->buffer_size; // wrap-around
 204
 205   if(space<s->fill_limit){
 206 //    printf("Buffer is full (%d bytes free, limit: %d)\n",space,s->fill_limit);
 207     return 0; // no fill...
 208   }
 209
 210 //  printf("### read=0x%X  back=%d  newb=%d  space=%d  pos=%d\n",read,back,newb,space,pos);
 211
 212   // try to avoid wrap-around. If not possible due to sector size
 213   // do an extra copy.
 214   if(space>s->buffer_size-pos) {
 215     if (s->buffer_size-pos >= s->sector_size) {
 216       space=s->buffer_size-pos;
 217     } else {
 218       space = s->sector_size;
 219       wraparound_copy = 1;
 220     }
 221   }
 222
 223   // limit one-time block size
 224   read_chunk = s->stream->read_chunk;
 225   if (!read_chunk) read_chunk = 4*s->sector_size;
 226   space = FFMIN(space, read_chunk);
 227
 228 #if 1
 229   // back+newb+space <= buffer_size
 230   back2=s->buffer_size-(space+newb); // max back size
 231   if(s->min_filepos<(read-back2)) s->min_filepos=read-back2;
 232 #else
 233   s->min_filepos=read-back; // avoid seeking-back to temp area...
 234 #endif
 235
 236   if (wraparound_copy) {
 237     int to_copy;
 238     len = stream_read_internal(s->stream, s->stream->buffer, space);
 239     to_copy = FFMIN(len, s->buffer_size-pos);
 240     memcpy(s->buffer + pos, s->stream->buffer, to_copy);
 241     memcpy(s->buffer, s->stream->buffer + to_copy, len - to_copy);
 242   } else
 243   len = stream_read_internal(s->stream, &s->buffer[pos], space);
 244   s->eof= !len;
 245
 246   s->max_filepos+=len;
 247   if(pos+len>=s->buffer_size){
 248       // wrap...
 249       s->offset+=s->buffer_size;
 250   }
 251
 252   return len;
 253
 254 }
 255
 256 static int cache_execute_control(cache_vars_t *s) {
 257   static unsigned last;
 258   int quit = s->control == -2;
 259   if (quit || !s->stream->control) {
 260     s->stream_time_length = 0;
 261     s->control_new_pos = 0;
 262     s->control_res = STREAM_UNSUPPORTED;
 263     s->control = -1;
 264     return !quit;
 265   }
 266   if (GetTimerMS() - last > 99) {
 267     double len;
 268     if (s->stream->control(s->stream, STREAM_CTRL_GET_TIME_LENGTH, &len) == STREAM_OK)
 269       s->stream_time_length = len;
 270     else
 271       s->stream_time_length = 0;
 272     last = GetTimerMS();
 273   }
 274   if (s->control == -1) return 1;
 275   switch (s->control) {
 276     case STREAM_CTRL_GET_CURRENT_TIME:
 277     case STREAM_CTRL_SEEK_TO_TIME:
 278     case STREAM_CTRL_GET_ASPECT_RATIO:
 279       s->control_res = s->stream->control(s->stream, s->control, &s->control_double_arg);
 280       break;
 281     case STREAM_CTRL_SEEK_TO_CHAPTER:
 282     case STREAM_CTRL_GET_NUM_CHAPTERS:
 283     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 284     case STREAM_CTRL_GET_NUM_ANGLES:
 285     case STREAM_CTRL_GET_ANGLE:
 286     case STREAM_CTRL_SET_ANGLE:
 287       s->control_res = s->stream->control(s->stream, s->control, &s->control_uint_arg);
 288       break;
 289     default:
 290       s->control_res = STREAM_UNSUPPORTED;
 291       break;
 292   }
 293   s->control_new_pos = s->stream->pos;
 294   s->control = -1;
 295   return 1;
 296 }
 297
 298 static void *shared_alloc(int size) {
 299 #if FORKED_CACHE
 300     return shmem_alloc(size);
 301 #else
 302     return malloc(size);
 303 #endif
 304 }
 305
 306 static void shared_free(void *ptr, int size) {
 307 #if FORKED_CACHE
 308     shmem_free(ptr, size);
 309 #else
 310     free(ptr);
 311 #endif
 312 }
 313
 314 static cache_vars_t* cache_init(int size,int sector){
 315   int num;
 316   cache_vars_t* s=shared_alloc(sizeof(cache_vars_t));
 317   if(s==NULL) return NULL;
 318
 319   memset(s,0,sizeof(cache_vars_t));
 320   num=size/sector;
 321   if(num < 16){
 322      num = 16;
 323   }//32kb min_size
 324   s->buffer_size=num*sector;
 325   s->sector_size=sector;
 326   s->buffer=shared_alloc(s->buffer_size);
 327
 328   if(s->buffer == NULL){
 329     shared_free(s, sizeof(cache_vars_t));
 330     return NULL;
 331   }
 332
 333   s->fill_limit=8*sector;
 334   s->back_size=s->buffer_size/2;
 335   return s;
 336 }
 337
 338 void cache_uninit(stream_t *s) {
 339   cache_vars_t* c = s->cache_data;
 340   if(s->cache_pid) {
 341 #if !FORKED_CACHE
 342     cache_do_control(s, -2, NULL);
 343 #else
 344     kill(s->cache_pid,SIGKILL);
 345     waitpid(s->cache_pid,NULL,0);
 346 #endif
 347     s->cache_pid = 0;
 348   }
 349   if(!c) return;
 350   shared_free(c->buffer, c->buffer_size);
 351   c->buffer = NULL;
 352   c->stream = NULL;
 353   shared_free(s->cache_data, sizeof(cache_vars_t));
 354   s->cache_data = NULL;
 355 }
 356
 357 static void exit_sighandler(int x){
 358   // close stream
 359   exit(0);
 360 }
 361
 362 static void dummy_sighandler(int x) {
 363 }
 364
 365 /**
 366  * Main loop of the cache process or thread.
 367  */
 368 static void cache_mainloop(cache_vars_t *s) {
 369     int sleep_count = 0;
 370 #if FORKED_CACHE
 371     struct sigaction sa = { .sa_handler = SIG_IGN };
 372     sigaction(SIGUSR1, &sa, NULL);
 373 #endif
 374     do {
 375         if (!cache_fill(s)) {
 376 #if FORKED_CACHE
 377             // Let signal wake us up, we cannot leave this
 378             // enabled since we do not handle EINTR in most places.
 379             // This might need extra code to work on BSD.
 380             sa.sa_handler = dummy_sighandler;
 381             sigaction(SIGUSR1, &sa, NULL);
 382 #endif
 383             if (sleep_count < INITIAL_FILL_USLEEP_COUNT) {
 384                 sleep_count++;
 385                 usec_sleep(INITIAL_FILL_USLEEP_TIME);
 386             } else
 387                 usec_sleep(FILL_USLEEP_TIME); // idle
 388 #if FORKED_CACHE
 389             sa.sa_handler = SIG_IGN;
 390             sigaction(SIGUSR1, &sa, NULL);
 391 #endif
 392         } else
 393             sleep_count = 0;
 394     } while (cache_execute_control(s));
 395 }
 396
 397 /**
 398  * \return 1 on success, 0 if the function was interrupted and -1 on error
 399  */
 400 int stream_enable_cache(stream_t *stream,int size,int min,int seek_limit){
 401   int ss = stream->sector_size ? stream->sector_size : STREAM_BUFFER_SIZE;
 402   int res = -1;
 403   cache_vars_t* s;
 404
 405   if (stream->flags & STREAM_NON_CACHEABLE) {
 406     mp_msg(MSGT_CACHE,MSGL_STATUS,"\rThis stream is non-cacheable\n");
 407     return 1;
 408   }
 409
 410   s=cache_init(size,ss);
 411   if(s == NULL) return -1;
 412   stream->cache_data=s;
 413   s->stream=stream; // callback
 414   s->seek_limit=seek_limit;
 415
 416
 417   //make sure that we won't wait from cache_fill
 418   //more data than it is allowed to fill
 419   if (s->seek_limit > s->buffer_size - s->fill_limit ){
 420      s->seek_limit = s->buffer_size - s->fill_limit;
 421   }
 422   if (min > s->buffer_size - s->fill_limit) {
 423      min = s->buffer_size - s->fill_limit;
 424   }
 425   // to make sure we wait for the cache process/thread to be active
 426   // before continuing
 427   if (min <= 0)
 428     min = 1;
 429
 430 #if FORKED_CACHE
 431   if((stream->cache_pid=fork())){
 432     if ((pid_t)stream->cache_pid == -1)
 433       stream->cache_pid = 0;
 434 #else
 435   {
 436     stream_t* stream2=malloc(sizeof(stream_t));
 437     memcpy(stream2,s->stream,sizeof(stream_t));
 438     s->stream=stream2;
 439 #if defined(__MINGW32__)
 440     stream->cache_pid = _beginthread( ThreadProc, 0, s );
 441 #elif defined(__OS2__)
 442     stream->cache_pid = _beginthread( ThreadProc, NULL, 256 * 1024, s );
 443 #else
 444     {
 445     pthread_t tid;
 446     pthread_create(&tid, NULL, ThreadProc, s);
 447     stream->cache_pid = 1;
 448     }
 449 #endif
 450 #endif
 451     if (!stream->cache_pid) {
 452         mp_msg(MSGT_CACHE, MSGL_ERR,
 453                "Starting cache process/thread failed: %s.\n", strerror(errno));
 454         goto err_out;
 455     }
 456     // wait until cache is filled at least prefill_init %
 457     mp_msg(MSGT_CACHE,MSGL_V,"CACHE_PRE_INIT: %"PRId64" [%"PRId64"] %"PRId64"  pre:%d  eof:%d  \n",
 458         (int64_t)s->min_filepos,(int64_t)s->read_filepos,(int64_t)s->max_filepos,min,s->eof);
 459     while(s->read_filepos<s->min_filepos || s->max_filepos-s->read_filepos<min){
 460         mp_tmsg(MSGT_CACHE,MSGL_STATUS,"\rCache fill: %5.2f%% (%"PRId64" bytes)   ",
 461             100.0*(float)(s->max_filepos-s->read_filepos)/(float)(s->buffer_size),
 462             (int64_t)s->max_filepos-s->read_filepos
 463         );
 464         if(s->eof) break; // file is smaller than prefill size
 465         if(stream_check_interrupt(PREFILL_SLEEP_TIME)) {
 466           res = 0;
 467           goto err_out;
 468         }
 469     }
 470     mp_msg(MSGT_CACHE,MSGL_STATUS,"\n");
 471     return 1; // parent exits
 472
 473 err_out:
 474     cache_uninit(stream);
 475     return res;
 476   }
 477
 478 #if FORKED_CACHE
 479   signal(SIGTERM,exit_sighandler); // kill
 480   cache_mainloop(s);
 481   // make sure forked code never leaves this function
 482   exit(0);
 483 #endif
 484 }
 485
 486 #if !FORKED_CACHE
 487 #if defined(__MINGW32__) || defined(__OS2__)
 488 static void ThreadProc( void *s ){
 489   cache_mainloop(s);
 490   _endthread();
 491 }
 492 #else
 493 static void *ThreadProc( void *s ){
 494   cache_mainloop(s);
 495   return NULL;
 496 }
 497 #endif
 498 #endif
 499
 500 int cache_stream_fill_buffer(stream_t *s){
 501   int len;
 502   int sector_size;
 503   if(!s->cache_pid) return stream_fill_buffer(s);
 504
 505   if(s->pos!=((cache_vars_t*)s->cache_data)->read_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"!!! read_filepos differs!!! report this bug...\n");
 506   sector_size = ((cache_vars_t*)s->cache_data)->sector_size;
 507   if (sector_size > STREAM_MAX_SECTOR_SIZE) {
 508     mp_msg(MSGT_CACHE, MSGL_ERR, "Sector size %i larger than maximum %i\n", sector_size, STREAM_MAX_SECTOR_SIZE);
 509     sector_size = STREAM_MAX_SECTOR_SIZE;
 510   }
 511
 512   len=cache_read(s->cache_data,s->buffer, sector_size);
 513   //printf("cache_stream_fill_buffer->read -> %d\n",len);
 514
 515   if(len<=0){ s->eof=1; s->buf_pos=s->buf_len=0; return 0; }
 516   s->eof=0;
 517   s->buf_pos=0;
 518   s->buf_len=len;
 519   s->pos+=len;
 520 //  printf("[%d]",len);fflush(stdout);
 521   if (s->capture_file)
 522     stream_capture_do(s);
 523   return len;
 524
 525 }
 526
 527 int cache_fill_status(stream_t *s) {
 528   cache_vars_t *cv;
 529   if (!s || !s->cache_data)
 530     return -1;
 531   cv = s->cache_data;
 532   return (cv->max_filepos-cv->read_filepos)/(cv->buffer_size / 100);
 533 }
 534
 535 int cache_stream_seek_long(stream_t *stream,off_t pos){
 536   cache_vars_t* s;
 537   off_t newpos;
 538   if(!stream->cache_pid) return stream_seek_long(stream,pos);
 539
 540   s=stream->cache_data;
 541 //  s->seek_lock=1;
 542
 543   mp_msg(MSGT_CACHE,MSGL_DBG2,"CACHE2_SEEK: 0x%"PRIX64" <= 0x%"PRIX64" (0x%"PRIX64") <= 0x%"PRIX64"  \n",s->min_filepos,pos,s->read_filepos,s->max_filepos);
 544
 545   newpos=pos/s->sector_size; newpos*=s->sector_size; // align
 546   stream->pos=s->read_filepos=newpos;
 547   s->eof=0; // !!!!!!!
 548   cache_wakeup(stream);
 549
 550   cache_stream_fill_buffer(stream);
 551
 552   pos-=newpos;
 553   if(pos>=0 && pos<=stream->buf_len){
 554     stream->buf_pos=pos; // byte position in sector
 555     return 1;
 556   }
 557
 558 //  stream->buf_pos=stream->buf_len=0;
 559 //  return 1;
 560
 561   mp_msg(MSGT_CACHE,MSGL_V,"cache_stream_seek: WARNING! Can't seek to 0x%"PRIX64" !\n",(int64_t)(pos+newpos));
 562   return 0;
 563 }
 564
 565 int cache_do_control(stream_t *stream, int cmd, void *arg) {
 566   int sleep_count = 0;
 567   cache_vars_t* s = stream->cache_data;
 568   switch (cmd) {
 569     case STREAM_CTRL_SEEK_TO_TIME:
 570       s->control_double_arg = *(double *)arg;
 571       s->control = cmd;
 572       break;
 573     case STREAM_CTRL_SEEK_TO_CHAPTER:
 574     case STREAM_CTRL_SET_ANGLE:
 575       s->control_uint_arg = *(unsigned *)arg;
 576       s->control = cmd;
 577       break;
 578 // the core might call these every frame, they are too slow for this...
 579     case STREAM_CTRL_GET_TIME_LENGTH:
 580 //    case STREAM_CTRL_GET_CURRENT_TIME:
 581       *(double *)arg = s->stream_time_length;
 582       return s->stream_time_length ? STREAM_OK : STREAM_UNSUPPORTED;
 583     case STREAM_CTRL_GET_NUM_CHAPTERS:
 584     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 585     case STREAM_CTRL_GET_ASPECT_RATIO:
 586     case STREAM_CTRL_GET_NUM_ANGLES:
 587     case STREAM_CTRL_GET_ANGLE:
 588     case -2:
 589       s->control = cmd;
 590       break;
 591     default:
 592       return STREAM_UNSUPPORTED;
 593   }
 594   cache_wakeup(stream);
 595   while (s->control != -1) {
 596     if (sleep_count++ == 1000)
 597       mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not responding!\n");
 598     if (stream_check_interrupt(CONTROL_SLEEP_TIME)) {
 599       s->eof = 1;
 600       return STREAM_UNSUPPORTED;
 601     }
 602   }
 603   switch (cmd) {
 604     case STREAM_CTRL_GET_TIME_LENGTH:
 605     case STREAM_CTRL_GET_CURRENT_TIME:
 606     case STREAM_CTRL_GET_ASPECT_RATIO:
 607       *(double *)arg = s->control_double_arg;
 608       break;
 609     case STREAM_CTRL_GET_NUM_CHAPTERS:
 610     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 611     case STREAM_CTRL_GET_NUM_ANGLES:
 612     case STREAM_CTRL_GET_ANGLE:
 613       *(unsigned *)arg = s->control_uint_arg;
 614       break;
 615     case STREAM_CTRL_SEEK_TO_CHAPTER:
 616     case STREAM_CTRL_SEEK_TO_TIME:
 617     case STREAM_CTRL_SET_ANGLE:
 618       if (s->control_res != STREAM_UNSUPPORTED)
 619           stream->pos = s->read_filepos = s->control_new_pos;
 620       break;
 621   }
 622   return s->control_res;
 623 }