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(PTHREAD_CACHE)
  49 #include <pthread.h>
  50 static void *ThreadProc(void *s);
  51 #else
  52 #include <sys/wait.h>
  53 #define FORKED_CACHE 1
  54 #endif
  55 #ifndef FORKED_CACHE
  56 #define FORKED_CACHE 0
  57 #endif
  58
  59 #include "mp_msg.h"
  60
  61 #include "stream.h"
  62 #include "cache2.h"
  63 #include "mpcommon.h"
  64
  65 typedef struct {
  66   // constats:
  67   unsigned char *buffer;      // base pointer of the allocated buffer memory
  68   int buffer_size; // size of the allocated buffer memory
  69   int sector_size; // size of a single sector (2048/2324)
  70   int back_size;   // we should keep back_size amount of old bytes for backward seek
  71   int fill_limit;  // we should fill buffer only if space>=fill_limit
  72   int seek_limit;  // keep filling cache if distance is less that seek limit
  73   // filler's pointers:
  74   int eof;
  75   off_t min_filepos; // buffer contain only a part of the file, from min-max pos
  76   off_t max_filepos;
  77   off_t offset;      // filepos <-> bufferpos  offset value (filepos of the buffer's first byte)
  78   // reader's pointers:
  79   off_t read_filepos;
  80   // commands/locking:
  81 //  int seek_lock;   // 1 if we will seek/reset buffer, 2 if we are ready for cmd
  82 //  int fifo_flag;  // 1 if we should use FIFO to notice cache about buffer reads.
  83   // callback
  84   stream_t* stream;
  85   volatile int control;
  86   volatile unsigned control_uint_arg;
  87   volatile double control_double_arg;
  88   volatile int control_res;
  89   volatile off_t control_new_pos;
  90   volatile double stream_time_length;
  91   volatile double stream_time_pos;
  92 } cache_vars_t;
  93
  94 static int min_fill=0;
  95
  96 static void cache_wakeup(stream_t *s)
  97 {
  98 #if FORKED_CACHE
  99   // signal process to wake up immediately
 100   kill(s->cache_pid, SIGUSR1);
 101 #endif
 102 }
 103
 104 static int cache_read(cache_vars_t *s, unsigned char *buf, int size)
 105 {
 106   int total=0;
 107   int sleep_count = 0;
 108   int last_max = s->max_filepos;
 109   while(size>0){
 110     int pos,newb,len;
 111
 112   //printf("CACHE2_READ: 0x%X <= 0x%X <= 0x%X  \n",s->min_filepos,s->read_filepos,s->max_filepos);
 113
 114     if(s->read_filepos>=s->max_filepos || s->read_filepos<s->min_filepos){
 115         // eof?
 116         if(s->eof) break;
 117         if (s->max_filepos == last_max) {
 118             if (sleep_count++ == 10)
 119                 mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not filling, consider increasing -cache and/or -cache-min!\n");
 120         } else {
 121             last_max = s->max_filepos;
 122             sleep_count = 0;
 123         }
 124         // waiting for buffer fill...
 125         if (stream_check_interrupt(READ_SLEEP_TIME)) {
 126             s->eof = 1;
 127             break;
 128         }
 129         continue; // try again...
 130     }
 131     sleep_count = 0;
 132
 133     newb=s->max_filepos-s->read_filepos; // new bytes in the buffer
 134     if(newb<min_fill) min_fill=newb; // statistics...
 135
 136 //    printf("*** newb: %d bytes ***\n",newb);
 137
 138     pos=s->read_filepos - s->offset;
 139     if(pos<0) pos+=s->buffer_size; else
 140     if(pos>=s->buffer_size) pos-=s->buffer_size;
 141
 142     if(newb>s->buffer_size-pos) newb=s->buffer_size-pos; // handle wrap...
 143     if(newb>size) newb=size;
 144
 145     // check:
 146     if(s->read_filepos<s->min_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"Ehh. s->read_filepos<s->min_filepos !!! Report bug...\n");
 147
 148     // len=write(mem,newb)
 149     //printf("Buffer read: %d bytes\n",newb);
 150     memcpy(buf,&s->buffer[pos],newb);
 151     buf+=newb;
 152     len=newb;
 153     // ...
 154
 155     s->read_filepos+=len;
 156     size-=len;
 157     total+=len;
 158
 159   }
 160   return total;
 161 }
 162
 163 static int cache_fill(cache_vars_t *s)
 164 {
 165   int back,back2,newb,space,len,pos;
 166   off_t read=s->read_filepos;
 167   int read_chunk;
 168   int wraparound_copy = 0;
 169
 170   if(read<s->min_filepos || read>s->max_filepos){
 171       // seek...
 172       mp_msg(MSGT_CACHE,MSGL_DBG2,"Out of boundaries... seeking to 0x%"PRIX64"  \n",(int64_t)read);
 173       // drop cache contents only if seeking backward or too much fwd.
 174       // This is also done for on-disk files, since it loses the backseek cache.
 175       // That in turn can cause major bandwidth increase and performance
 176       // issues with e.g. mov or badly interleaved files
 177       if(read<s->min_filepos || read>=s->max_filepos+s->seek_limit)
 178       {
 179         s->offset= // FIXME!?
 180         s->min_filepos=s->max_filepos=read; // drop cache content :(
 181         if(s->stream->eof) stream_reset(s->stream);
 182         stream_seek_internal(s->stream,read);
 183         mp_msg(MSGT_CACHE,MSGL_DBG2,"Seek done. new pos: 0x%"PRIX64"  \n",(int64_t)stream_tell(s->stream));
 184       }
 185   }
 186
 187   // calc number of back-bytes:
 188   back=read - s->min_filepos;
 189   if(back<0) back=0; // strange...
 190   if(back>s->back_size) back=s->back_size;
 191
 192   // calc number of new bytes:
 193   newb=s->max_filepos - read;
 194   if(newb<0) newb=0; // strange...
 195
 196   // calc free buffer space:
 197   space=s->buffer_size - (newb+back);
 198
 199   // calc bufferpos:
 200   pos=s->max_filepos - s->offset;
 201   if(pos>=s->buffer_size) pos-=s->buffer_size; // wrap-around
 202
 203   if(space<s->fill_limit){
 204 //    printf("Buffer is full (%d bytes free, limit: %d)\n",space,s->fill_limit);
 205     return 0; // no fill...
 206   }
 207
 208 //  printf("### read=0x%X  back=%d  newb=%d  space=%d  pos=%d\n",read,back,newb,space,pos);
 209
 210   // try to avoid wrap-around. If not possible due to sector size
 211   // do an extra copy.
 212   if(space>s->buffer_size-pos) {
 213     if (s->buffer_size-pos >= s->sector_size) {
 214       space=s->buffer_size-pos;
 215     } else {
 216       space = s->sector_size;
 217       wraparound_copy = 1;
 218     }
 219   }
 220
 221   // limit one-time block size
 222   read_chunk = s->stream->read_chunk;
 223   if (!read_chunk) read_chunk = 4*s->sector_size;
 224   space = FFMIN(space, read_chunk);
 225
 226 #if 1
 227   // back+newb+space <= buffer_size
 228   back2=s->buffer_size-(space+newb); // max back size
 229   if(s->min_filepos<(read-back2)) s->min_filepos=read-back2;
 230 #else
 231   s->min_filepos=read-back; // avoid seeking-back to temp area...
 232 #endif
 233
 234   if (wraparound_copy) {
 235     int to_copy;
 236     len = stream_read_internal(s->stream, s->stream->buffer, space);
 237     to_copy = FFMIN(len, s->buffer_size-pos);
 238     memcpy(s->buffer + pos, s->stream->buffer, to_copy);
 239     memcpy(s->buffer, s->stream->buffer + to_copy, len - to_copy);
 240   } else
 241   len = stream_read_internal(s->stream, &s->buffer[pos], space);
 242   s->eof= !len;
 243
 244   s->max_filepos+=len;
 245   if(pos+len>=s->buffer_size){
 246       // wrap...
 247       s->offset+=s->buffer_size;
 248   }
 249
 250   return len;
 251
 252 }
 253
 254 static int cache_execute_control(cache_vars_t *s) {
 255   double double_res;
 256   unsigned uint_res;
 257   static unsigned last;
 258   int quit = s->control == -2;
 259   if (quit || !s->stream->control) {
 260     s->stream_time_length = 0;
 261     s->stream_time_pos = MP_NOPTS_VALUE;
 262     s->control_new_pos = 0;
 263     s->control_res = STREAM_UNSUPPORTED;
 264     s->control = -1;
 265     return !quit;
 266   }
 267   if (GetTimerMS() - last > 99) {
 268     double len, pos;
 269     if (s->stream->control(s->stream, STREAM_CTRL_GET_TIME_LENGTH, &len) == STREAM_OK)
 270       s->stream_time_length = len;
 271     else
 272       s->stream_time_length = 0;
 273     if (s->stream->control(s->stream, STREAM_CTRL_GET_CURRENT_TIME, &pos) == STREAM_OK)
 274       s->stream_time_pos = pos;
 275     else
 276       s->stream_time_pos = MP_NOPTS_VALUE;
 277     last = GetTimerMS();
 278   }
 279   if (s->control == -1) return 1;
 280   switch (s->control) {
 281     case STREAM_CTRL_SEEK_TO_TIME:
 282       double_res = s->control_double_arg;
 283     case STREAM_CTRL_GET_CURRENT_TIME:
 284     case STREAM_CTRL_GET_ASPECT_RATIO:
 285       s->control_res = s->stream->control(s->stream, s->control, &double_res);
 286       s->control_double_arg = double_res;
 287       break;
 288     case STREAM_CTRL_SEEK_TO_CHAPTER:
 289     case STREAM_CTRL_SET_ANGLE:
 290       uint_res = s->control_uint_arg;
 291     case STREAM_CTRL_GET_NUM_CHAPTERS:
 292     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 293     case STREAM_CTRL_GET_NUM_ANGLES:
 294     case STREAM_CTRL_GET_ANGLE:
 295       s->control_res = s->stream->control(s->stream, s->control, &uint_res);
 296       s->control_uint_arg = uint_res;
 297       break;
 298     default:
 299       s->control_res = STREAM_UNSUPPORTED;
 300       break;
 301   }
 302   s->control_new_pos = s->stream->pos;
 303   s->control = -1;
 304   return 1;
 305 }
 306
 307 static void *shared_alloc(int size) {
 308 #if FORKED_CACHE
 309     return shmem_alloc(size);
 310 #else
 311     return malloc(size);
 312 #endif
 313 }
 314
 315 static void shared_free(void *ptr, int size) {
 316 #if FORKED_CACHE
 317     shmem_free(ptr, size);
 318 #else
 319     free(ptr);
 320 #endif
 321 }
 322
 323 static cache_vars_t* cache_init(int size,int sector){
 324   int num;
 325   cache_vars_t* s=shared_alloc(sizeof(cache_vars_t));
 326   if(s==NULL) return NULL;
 327
 328   memset(s,0,sizeof(cache_vars_t));
 329   num=size/sector;
 330   if(num < 16){
 331      num = 16;
 332   }//32kb min_size
 333   s->buffer_size=num*sector;
 334   s->sector_size=sector;
 335   s->buffer=shared_alloc(s->buffer_size);
 336
 337   if(s->buffer == NULL){
 338     shared_free(s, sizeof(cache_vars_t));
 339     return NULL;
 340   }
 341
 342   s->fill_limit=8*sector;
 343   s->back_size=s->buffer_size/2;
 344   return s;
 345 }
 346
 347 void cache_uninit(stream_t *s) {
 348   cache_vars_t* c = s->cache_data;
 349   if(s->cache_pid) {
 350 #if !FORKED_CACHE
 351     cache_do_control(s, -2, NULL);
 352 #else
 353     kill(s->cache_pid,SIGKILL);
 354     waitpid(s->cache_pid,NULL,0);
 355 #endif
 356     s->cache_pid = 0;
 357   }
 358   if(!c) return;
 359   shared_free(c->buffer, c->buffer_size);
 360   c->buffer = NULL;
 361   c->stream = NULL;
 362   shared_free(s->cache_data, sizeof(cache_vars_t));
 363   s->cache_data = NULL;
 364 }
 365
 366 #if FORKED_CACHE
 367 static void exit_sighandler(int x){
 368   // close stream
 369   exit(0);
 370 }
 371
 372 static void dummy_sighandler(int x) {
 373 }
 374 #endif
 375
 376 /**
 377  * Main loop of the cache process or thread.
 378  */
 379 static void cache_mainloop(cache_vars_t *s) {
 380     int sleep_count = 0;
 381 #if FORKED_CACHE
 382     struct sigaction sa = { .sa_handler = SIG_IGN };
 383     sigaction(SIGUSR1, &sa, NULL);
 384 #endif
 385     do {
 386         if (!cache_fill(s)) {
 387 #if FORKED_CACHE
 388             // Let signal wake us up, we cannot leave this
 389             // enabled since we do not handle EINTR in most places.
 390             // This might need extra code to work on BSD.
 391             sa.sa_handler = dummy_sighandler;
 392             sigaction(SIGUSR1, &sa, NULL);
 393 #endif
 394             if (sleep_count < INITIAL_FILL_USLEEP_COUNT) {
 395                 sleep_count++;
 396                 usec_sleep(INITIAL_FILL_USLEEP_TIME);
 397             } else
 398                 usec_sleep(FILL_USLEEP_TIME); // idle
 399 #if FORKED_CACHE
 400             sa.sa_handler = SIG_IGN;
 401             sigaction(SIGUSR1, &sa, NULL);
 402 #endif
 403         } else
 404             sleep_count = 0;
 405     } while (cache_execute_control(s));
 406 }
 407
 408 /**
 409  * \return 1 on success, 0 if the function was interrupted and -1 on error
 410  */
 411 int stream_enable_cache(stream_t *stream,int size,int min,int seek_limit){
 412   int ss = stream->sector_size ? stream->sector_size : STREAM_BUFFER_SIZE;
 413   int res = -1;
 414   cache_vars_t* s;
 415
 416   if (stream->flags & STREAM_NON_CACHEABLE) {
 417     mp_msg(MSGT_CACHE,MSGL_STATUS,"\rThis stream is non-cacheable\n");
 418     return 1;
 419   }
 420
 421   s=cache_init(size,ss);
 422   if(s == NULL) return -1;
 423   stream->cache_data=s;
 424   s->stream=stream; // callback
 425   s->seek_limit=seek_limit;
 426
 427
 428   //make sure that we won't wait from cache_fill
 429   //more data than it is allowed to fill
 430   if (s->seek_limit > s->buffer_size - s->fill_limit ){
 431      s->seek_limit = s->buffer_size - s->fill_limit;
 432   }
 433   if (min > s->buffer_size - s->fill_limit) {
 434      min = s->buffer_size - s->fill_limit;
 435   }
 436   // to make sure we wait for the cache process/thread to be active
 437   // before continuing
 438   if (min <= 0)
 439     min = 1;
 440
 441 #if FORKED_CACHE
 442   if((stream->cache_pid=fork())){
 443     if ((pid_t)stream->cache_pid == -1)
 444       stream->cache_pid = 0;
 445 #else
 446   {
 447     stream_t* stream2=malloc(sizeof(stream_t));
 448     memcpy(stream2,s->stream,sizeof(stream_t));
 449     s->stream=stream2;
 450 #if defined(__MINGW32__)
 451     stream->cache_pid = _beginthread( ThreadProc, 0, s );
 452 #else
 453     {
 454     pthread_t tid;
 455     pthread_create(&tid, NULL, ThreadProc, s);
 456     stream->cache_pid = 1;
 457     }
 458 #endif
 459 #endif
 460     if (!stream->cache_pid) {
 461         mp_msg(MSGT_CACHE, MSGL_ERR,
 462                "Starting cache process/thread failed: %s.\n", strerror(errno));
 463         goto err_out;
 464     }
 465     // wait until cache is filled at least prefill_init %
 466     mp_msg(MSGT_CACHE,MSGL_V,"CACHE_PRE_INIT: %"PRId64" [%"PRId64"] %"PRId64"  pre:%d  eof:%d  \n",
 467         (int64_t)s->min_filepos,(int64_t)s->read_filepos,(int64_t)s->max_filepos,min,s->eof);
 468     while(s->read_filepos<s->min_filepos || s->max_filepos-s->read_filepos<min){
 469         mp_tmsg(MSGT_CACHE,MSGL_STATUS,"\rCache fill: %5.2f%% (%"PRId64" bytes)   ",
 470             100.0*(float)(s->max_filepos-s->read_filepos)/(float)(s->buffer_size),
 471             (int64_t)s->max_filepos-s->read_filepos
 472         );
 473         if(s->eof) break; // file is smaller than prefill size
 474         if(stream_check_interrupt(PREFILL_SLEEP_TIME)) {
 475           res = 0;
 476           goto err_out;
 477         }
 478     }
 479     mp_msg(MSGT_CACHE,MSGL_STATUS,"\n");
 480     return 1; // parent exits
 481
 482 err_out:
 483     cache_uninit(stream);
 484     return res;
 485   }
 486
 487 #if FORKED_CACHE
 488   signal(SIGTERM,exit_sighandler); // kill
 489   cache_mainloop(s);
 490   // make sure forked code never leaves this function
 491   exit(0);
 492 #endif
 493 }
 494
 495 #if !FORKED_CACHE
 496 #if defined(__MINGW32__)
 497 static void ThreadProc( void *s ){
 498   cache_mainloop(s);
 499   _endthread();
 500 }
 501 #else
 502 static void *ThreadProc( void *s ){
 503   cache_mainloop(s);
 504   return NULL;
 505 }
 506 #endif
 507 #endif
 508
 509 int cache_stream_fill_buffer(stream_t *s){
 510   int len;
 511   int sector_size;
 512   if(!s->cache_pid) return stream_fill_buffer(s);
 513
 514   if(s->pos!=((cache_vars_t*)s->cache_data)->read_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"!!! read_filepos differs!!! report this bug...\n");
 515   sector_size = ((cache_vars_t*)s->cache_data)->sector_size;
 516   if (sector_size > STREAM_MAX_SECTOR_SIZE) {
 517     mp_msg(MSGT_CACHE, MSGL_ERR, "Sector size %i larger than maximum %i\n", sector_size, STREAM_MAX_SECTOR_SIZE);
 518     sector_size = STREAM_MAX_SECTOR_SIZE;
 519   }
 520
 521   len=cache_read(s->cache_data,s->buffer, sector_size);
 522   //printf("cache_stream_fill_buffer->read -> %d\n",len);
 523
 524   if(len<=0){ s->eof=1; s->buf_pos=s->buf_len=0; return 0; }
 525   s->eof=0;
 526   s->buf_pos=0;
 527   s->buf_len=len;
 528   s->pos+=len;
 529 //  printf("[%d]",len);fflush(stdout);
 530   if (s->capture_file)
 531     stream_capture_do(s);
 532   return len;
 533
 534 }
 535
 536 int cache_fill_status(stream_t *s) {
 537   cache_vars_t *cv;
 538   if (!s || !s->cache_data)
 539     return -1;
 540   cv = s->cache_data;
 541   return (cv->max_filepos-cv->read_filepos)/(cv->buffer_size / 100);
 542 }
 543
 544 int cache_stream_seek_long(stream_t *stream,off_t pos){
 545   cache_vars_t* s;
 546   off_t newpos;
 547   if(!stream->cache_pid) return stream_seek_long(stream,pos);
 548
 549   s=stream->cache_data;
 550 //  s->seek_lock=1;
 551
 552   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);
 553
 554   newpos=pos/s->sector_size; newpos*=s->sector_size; // align
 555   stream->pos=s->read_filepos=newpos;
 556   s->eof=0; // !!!!!!!
 557   cache_wakeup(stream);
 558
 559   cache_stream_fill_buffer(stream);
 560
 561   pos-=newpos;
 562   if(pos>=0 && pos<=stream->buf_len){
 563     stream->buf_pos=pos; // byte position in sector
 564     return 1;
 565   }
 566
 567 //  stream->buf_pos=stream->buf_len=0;
 568 //  return 1;
 569
 570   mp_msg(MSGT_CACHE,MSGL_V,"cache_stream_seek: WARNING! Can't seek to 0x%"PRIX64" !\n",(int64_t)(pos+newpos));
 571   return 0;
 572 }
 573
 574 int cache_do_control(stream_t *stream, int cmd, void *arg) {
 575   int sleep_count = 0;
 576   cache_vars_t* s = stream->cache_data;
 577   switch (cmd) {
 578     case STREAM_CTRL_SEEK_TO_TIME:
 579       s->control_double_arg = *(double *)arg;
 580       s->control = cmd;
 581       break;
 582     case STREAM_CTRL_SEEK_TO_CHAPTER:
 583     case STREAM_CTRL_SET_ANGLE:
 584       s->control_uint_arg = *(unsigned *)arg;
 585       s->control = cmd;
 586       break;
 587     // the core might call these every frame, so cache them...
 588     case STREAM_CTRL_GET_TIME_LENGTH:
 589       *(double *)arg = s->stream_time_length;
 590       return s->stream_time_length ? STREAM_OK : STREAM_UNSUPPORTED;
 591     case STREAM_CTRL_GET_CURRENT_TIME:
 592       *(double *)arg = s->stream_time_pos;
 593       return s->stream_time_pos != MP_NOPTS_VALUE ? STREAM_OK : STREAM_UNSUPPORTED;
 594     case STREAM_CTRL_GET_NUM_CHAPTERS:
 595     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 596     case STREAM_CTRL_GET_ASPECT_RATIO:
 597     case STREAM_CTRL_GET_NUM_ANGLES:
 598     case STREAM_CTRL_GET_ANGLE:
 599     case -2:
 600       s->control = cmd;
 601       break;
 602     default:
 603       return STREAM_UNSUPPORTED;
 604   }
 605   cache_wakeup(stream);
 606   while (s->control != -1) {
 607     if (sleep_count++ == 1000)
 608       mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not responding!\n");
 609     if (stream_check_interrupt(CONTROL_SLEEP_TIME)) {
 610       s->eof = 1;
 611       return STREAM_UNSUPPORTED;
 612     }
 613   }
 614   if (s->control_res != STREAM_OK)
 615     return s->control_res;
 616   switch (cmd) {
 617     case STREAM_CTRL_GET_TIME_LENGTH:
 618     case STREAM_CTRL_GET_CURRENT_TIME:
 619     case STREAM_CTRL_GET_ASPECT_RATIO:
 620       *(double *)arg = s->control_double_arg;
 621       break;
 622     case STREAM_CTRL_GET_NUM_CHAPTERS:
 623     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 624     case STREAM_CTRL_GET_NUM_ANGLES:
 625     case STREAM_CTRL_GET_ANGLE:
 626       *(unsigned *)arg = s->control_uint_arg;
 627       break;
 628     case STREAM_CTRL_SEEK_TO_CHAPTER:
 629     case STREAM_CTRL_SEEK_TO_TIME:
 630     case STREAM_CTRL_SET_ANGLE:
 631       stream->pos = s->read_filepos = s->control_new_pos;
 632       break;
 633   }
 634   return s->control_res;
 635 }