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 #include "mpcommon.h"
  68
  69 typedef struct {
  70   // constats:
  71   unsigned char *buffer;      // base pointer of the allocated buffer memory
  72   int buffer_size; // size of the allocated buffer memory
  73   int sector_size; // size of a single sector (2048/2324)
  74   int back_size;   // we should keep back_size amount of old bytes for backward seek
  75   int fill_limit;  // we should fill buffer only if space>=fill_limit
  76   int seek_limit;  // keep filling cache if distance is less that seek limit
  77   // filler's pointers:
  78   int eof;
  79   off_t min_filepos; // buffer contain only a part of the file, from min-max pos
  80   off_t max_filepos;
  81   off_t offset;      // filepos <-> bufferpos  offset value (filepos of the buffer's first byte)
  82   // reader's pointers:
  83   off_t read_filepos;
  84   // commands/locking:
  85 //  int seek_lock;   // 1 if we will seek/reset buffer, 2 if we are ready for cmd
  86 //  int fifo_flag;  // 1 if we should use FIFO to notice cache about buffer reads.
  87   // callback
  88   stream_t* stream;
  89   volatile int control;
  90   volatile unsigned control_uint_arg;
  91   volatile double control_double_arg;
  92   volatile int control_res;
  93   volatile off_t control_new_pos;
  94   volatile double stream_time_length;
  95   volatile double stream_time_pos;
  96 } cache_vars_t;
  97
  98 static int min_fill=0;
  99
 100 static void cache_wakeup(stream_t *s)
 101 {
 102 #if FORKED_CACHE
 103   // signal process to wake up immediately
 104   kill(s->cache_pid, SIGUSR1);
 105 #endif
 106 }
 107
 108 static int cache_read(cache_vars_t *s, unsigned char *buf, int size)
 109 {
 110   int total=0;
 111   int sleep_count = 0;
 112   int last_max = s->max_filepos;
 113   while(size>0){
 114     int pos,newb,len;
 115
 116   //printf("CACHE2_READ: 0x%X <= 0x%X <= 0x%X  \n",s->min_filepos,s->read_filepos,s->max_filepos);
 117
 118     if(s->read_filepos>=s->max_filepos || s->read_filepos<s->min_filepos){
 119         // eof?
 120         if(s->eof) break;
 121         if (s->max_filepos == last_max) {
 122             if (sleep_count++ == 10)
 123                 mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not filling, consider increasing -cache and/or -cache-min!\n");
 124         } else {
 125             last_max = s->max_filepos;
 126             sleep_count = 0;
 127         }
 128         // waiting for buffer fill...
 129         if (stream_check_interrupt(READ_SLEEP_TIME)) {
 130             s->eof = 1;
 131             break;
 132         }
 133         continue; // try again...
 134     }
 135     sleep_count = 0;
 136
 137     newb=s->max_filepos-s->read_filepos; // new bytes in the buffer
 138     if(newb<min_fill) min_fill=newb; // statistics...
 139
 140 //    printf("*** newb: %d bytes ***\n",newb);
 141
 142     pos=s->read_filepos - s->offset;
 143     if(pos<0) pos+=s->buffer_size; else
 144     if(pos>=s->buffer_size) pos-=s->buffer_size;
 145
 146     if(newb>s->buffer_size-pos) newb=s->buffer_size-pos; // handle wrap...
 147     if(newb>size) newb=size;
 148
 149     // check:
 150     if(s->read_filepos<s->min_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"Ehh. s->read_filepos<s->min_filepos !!! Report bug...\n");
 151
 152     // len=write(mem,newb)
 153     //printf("Buffer read: %d bytes\n",newb);
 154     memcpy(buf,&s->buffer[pos],newb);
 155     buf+=newb;
 156     len=newb;
 157     // ...
 158
 159     s->read_filepos+=len;
 160     size-=len;
 161     total+=len;
 162
 163   }
 164   return total;
 165 }
 166
 167 static int cache_fill(cache_vars_t *s)
 168 {
 169   int back,back2,newb,space,len,pos;
 170   off_t read=s->read_filepos;
 171   int read_chunk;
 172   int wraparound_copy = 0;
 173
 174   if(read<s->min_filepos || read>s->max_filepos){
 175       // seek...
 176       mp_msg(MSGT_CACHE,MSGL_DBG2,"Out of boundaries... seeking to 0x%"PRIX64"  \n",(int64_t)read);
 177       // drop cache contents only if seeking backward or too much fwd.
 178       // This is also done for on-disk files, since it loses the backseek cache.
 179       // That in turn can cause major bandwidth increase and performance
 180       // issues with e.g. mov or badly interleaved files
 181       if(read<s->min_filepos || read>=s->max_filepos+s->seek_limit)
 182       {
 183         s->offset= // FIXME!?
 184         s->min_filepos=s->max_filepos=read; // drop cache content :(
 185         if(s->stream->eof) stream_reset(s->stream);
 186         stream_seek_internal(s->stream,read);
 187         mp_msg(MSGT_CACHE,MSGL_DBG2,"Seek done. new pos: 0x%"PRIX64"  \n",(int64_t)stream_tell(s->stream));
 188       }
 189   }
 190
 191   // calc number of back-bytes:
 192   back=read - s->min_filepos;
 193   if(back<0) back=0; // strange...
 194   if(back>s->back_size) back=s->back_size;
 195
 196   // calc number of new bytes:
 197   newb=s->max_filepos - read;
 198   if(newb<0) newb=0; // strange...
 199
 200   // calc free buffer space:
 201   space=s->buffer_size - (newb+back);
 202
 203   // calc bufferpos:
 204   pos=s->max_filepos - s->offset;
 205   if(pos>=s->buffer_size) pos-=s->buffer_size; // wrap-around
 206
 207   if(space<s->fill_limit){
 208 //    printf("Buffer is full (%d bytes free, limit: %d)\n",space,s->fill_limit);
 209     return 0; // no fill...
 210   }
 211
 212 //  printf("### read=0x%X  back=%d  newb=%d  space=%d  pos=%d\n",read,back,newb,space,pos);
 213
 214   // try to avoid wrap-around. If not possible due to sector size
 215   // do an extra copy.
 216   if(space>s->buffer_size-pos) {
 217     if (s->buffer_size-pos >= s->sector_size) {
 218       space=s->buffer_size-pos;
 219     } else {
 220       space = s->sector_size;
 221       wraparound_copy = 1;
 222     }
 223   }
 224
 225   // limit one-time block size
 226   read_chunk = s->stream->read_chunk;
 227   if (!read_chunk) read_chunk = 4*s->sector_size;
 228   space = FFMIN(space, read_chunk);
 229
 230 #if 1
 231   // back+newb+space <= buffer_size
 232   back2=s->buffer_size-(space+newb); // max back size
 233   if(s->min_filepos<(read-back2)) s->min_filepos=read-back2;
 234 #else
 235   s->min_filepos=read-back; // avoid seeking-back to temp area...
 236 #endif
 237
 238   if (wraparound_copy) {
 239     int to_copy;
 240     len = stream_read_internal(s->stream, s->stream->buffer, space);
 241     to_copy = FFMIN(len, s->buffer_size-pos);
 242     memcpy(s->buffer + pos, s->stream->buffer, to_copy);
 243     memcpy(s->buffer, s->stream->buffer + to_copy, len - to_copy);
 244   } else
 245   len = stream_read_internal(s->stream, &s->buffer[pos], space);
 246   s->eof= !len;
 247
 248   s->max_filepos+=len;
 249   if(pos+len>=s->buffer_size){
 250       // wrap...
 251       s->offset+=s->buffer_size;
 252   }
 253
 254   return len;
 255
 256 }
 257
 258 static int cache_execute_control(cache_vars_t *s) {
 259   double double_res;
 260   unsigned uint_res;
 261   static unsigned last;
 262   int quit = s->control == -2;
 263   if (quit || !s->stream->control) {
 264     s->stream_time_length = 0;
 265     s->stream_time_pos = MP_NOPTS_VALUE;
 266     s->control_new_pos = 0;
 267     s->control_res = STREAM_UNSUPPORTED;
 268     s->control = -1;
 269     return !quit;
 270   }
 271   if (GetTimerMS() - last > 99) {
 272     double len, pos;
 273     if (s->stream->control(s->stream, STREAM_CTRL_GET_TIME_LENGTH, &len) == STREAM_OK)
 274       s->stream_time_length = len;
 275     else
 276       s->stream_time_length = 0;
 277     if (s->stream->control(s->stream, STREAM_CTRL_GET_CURRENT_TIME, &pos) == STREAM_OK)
 278       s->stream_time_pos = pos;
 279     else
 280       s->stream_time_pos = MP_NOPTS_VALUE;
 281     last = GetTimerMS();
 282   }
 283   if (s->control == -1) return 1;
 284   switch (s->control) {
 285     case STREAM_CTRL_SEEK_TO_TIME:
 286       double_res = s->control_double_arg;
 287     case STREAM_CTRL_GET_CURRENT_TIME:
 288     case STREAM_CTRL_GET_ASPECT_RATIO:
 289       s->control_res = s->stream->control(s->stream, s->control, &double_res);
 290       s->control_double_arg = double_res;
 291       break;
 292     case STREAM_CTRL_SEEK_TO_CHAPTER:
 293     case STREAM_CTRL_SET_ANGLE:
 294       uint_res = s->control_uint_arg;
 295     case STREAM_CTRL_GET_NUM_CHAPTERS:
 296     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 297     case STREAM_CTRL_GET_NUM_ANGLES:
 298     case STREAM_CTRL_GET_ANGLE:
 299       s->control_res = s->stream->control(s->stream, s->control, &uint_res);
 300       s->control_uint_arg = uint_res;
 301       break;
 302     default:
 303       s->control_res = STREAM_UNSUPPORTED;
 304       break;
 305   }
 306   s->control_new_pos = s->stream->pos;
 307   s->control = -1;
 308   return 1;
 309 }
 310
 311 static void *shared_alloc(int size) {
 312 #if FORKED_CACHE
 313     return shmem_alloc(size);
 314 #else
 315     return malloc(size);
 316 #endif
 317 }
 318
 319 static void shared_free(void *ptr, int size) {
 320 #if FORKED_CACHE
 321     shmem_free(ptr, size);
 322 #else
 323     free(ptr);
 324 #endif
 325 }
 326
 327 static cache_vars_t* cache_init(int size,int sector){
 328   int num;
 329   cache_vars_t* s=shared_alloc(sizeof(cache_vars_t));
 330   if(s==NULL) return NULL;
 331
 332   memset(s,0,sizeof(cache_vars_t));
 333   num=size/sector;
 334   if(num < 16){
 335      num = 16;
 336   }//32kb min_size
 337   s->buffer_size=num*sector;
 338   s->sector_size=sector;
 339   s->buffer=shared_alloc(s->buffer_size);
 340
 341   if(s->buffer == NULL){
 342     shared_free(s, sizeof(cache_vars_t));
 343     return NULL;
 344   }
 345
 346   s->fill_limit=8*sector;
 347   s->back_size=s->buffer_size/2;
 348   return s;
 349 }
 350
 351 void cache_uninit(stream_t *s) {
 352   cache_vars_t* c = s->cache_data;
 353   if(s->cache_pid) {
 354 #if !FORKED_CACHE
 355     cache_do_control(s, -2, NULL);
 356 #else
 357     kill(s->cache_pid,SIGKILL);
 358     waitpid(s->cache_pid,NULL,0);
 359 #endif
 360     s->cache_pid = 0;
 361   }
 362   if(!c) return;
 363   shared_free(c->buffer, c->buffer_size);
 364   c->buffer = NULL;
 365   c->stream = NULL;
 366   shared_free(s->cache_data, sizeof(cache_vars_t));
 367   s->cache_data = NULL;
 368 }
 369
 370 #if FORKED_CACHE
 371 static void exit_sighandler(int x){
 372   // close stream
 373   exit(0);
 374 }
 375
 376 static void dummy_sighandler(int x) {
 377 }
 378 #endif
 379
 380 /**
 381  * Main loop of the cache process or thread.
 382  */
 383 static void cache_mainloop(cache_vars_t *s) {
 384     int sleep_count = 0;
 385 #if FORKED_CACHE
 386     struct sigaction sa = { .sa_handler = SIG_IGN };
 387     sigaction(SIGUSR1, &sa, NULL);
 388 #endif
 389     do {
 390         if (!cache_fill(s)) {
 391 #if FORKED_CACHE
 392             // Let signal wake us up, we cannot leave this
 393             // enabled since we do not handle EINTR in most places.
 394             // This might need extra code to work on BSD.
 395             sa.sa_handler = dummy_sighandler;
 396             sigaction(SIGUSR1, &sa, NULL);
 397 #endif
 398             if (sleep_count < INITIAL_FILL_USLEEP_COUNT) {
 399                 sleep_count++;
 400                 usec_sleep(INITIAL_FILL_USLEEP_TIME);
 401             } else
 402                 usec_sleep(FILL_USLEEP_TIME); // idle
 403 #if FORKED_CACHE
 404             sa.sa_handler = SIG_IGN;
 405             sigaction(SIGUSR1, &sa, NULL);
 406 #endif
 407         } else
 408             sleep_count = 0;
 409     } while (cache_execute_control(s));
 410 }
 411
 412 /**
 413  * \return 1 on success, 0 if the function was interrupted and -1 on error
 414  */
 415 int stream_enable_cache(stream_t *stream,int size,int min,int seek_limit){
 416   int ss = stream->sector_size ? stream->sector_size : STREAM_BUFFER_SIZE;
 417   int res = -1;
 418   cache_vars_t* s;
 419
 420   if (stream->flags & STREAM_NON_CACHEABLE) {
 421     mp_msg(MSGT_CACHE,MSGL_STATUS,"\rThis stream is non-cacheable\n");
 422     return 1;
 423   }
 424
 425   s=cache_init(size,ss);
 426   if(s == NULL) return -1;
 427   stream->cache_data=s;
 428   s->stream=stream; // callback
 429   s->seek_limit=seek_limit;
 430
 431
 432   //make sure that we won't wait from cache_fill
 433   //more data than it is allowed to fill
 434   if (s->seek_limit > s->buffer_size - s->fill_limit ){
 435      s->seek_limit = s->buffer_size - s->fill_limit;
 436   }
 437   if (min > s->buffer_size - s->fill_limit) {
 438      min = s->buffer_size - s->fill_limit;
 439   }
 440   // to make sure we wait for the cache process/thread to be active
 441   // before continuing
 442   if (min <= 0)
 443     min = 1;
 444
 445 #if FORKED_CACHE
 446   if((stream->cache_pid=fork())){
 447     if ((pid_t)stream->cache_pid == -1)
 448       stream->cache_pid = 0;
 449 #else
 450   {
 451     stream_t* stream2=malloc(sizeof(stream_t));
 452     memcpy(stream2,s->stream,sizeof(stream_t));
 453     s->stream=stream2;
 454 #if defined(__MINGW32__)
 455     stream->cache_pid = _beginthread( ThreadProc, 0, s );
 456 #elif defined(__OS2__)
 457     stream->cache_pid = _beginthread( ThreadProc, NULL, 256 * 1024, s );
 458 #else
 459     {
 460     pthread_t tid;
 461     pthread_create(&tid, NULL, ThreadProc, s);
 462     stream->cache_pid = 1;
 463     }
 464 #endif
 465 #endif
 466     if (!stream->cache_pid) {
 467         mp_msg(MSGT_CACHE, MSGL_ERR,
 468                "Starting cache process/thread failed: %s.\n", strerror(errno));
 469         goto err_out;
 470     }
 471     // wait until cache is filled at least prefill_init %
 472     mp_msg(MSGT_CACHE,MSGL_V,"CACHE_PRE_INIT: %"PRId64" [%"PRId64"] %"PRId64"  pre:%d  eof:%d  \n",
 473         (int64_t)s->min_filepos,(int64_t)s->read_filepos,(int64_t)s->max_filepos,min,s->eof);
 474     while(s->read_filepos<s->min_filepos || s->max_filepos-s->read_filepos<min){
 475         mp_tmsg(MSGT_CACHE,MSGL_STATUS,"\rCache fill: %5.2f%% (%"PRId64" bytes)   ",
 476             100.0*(float)(s->max_filepos-s->read_filepos)/(float)(s->buffer_size),
 477             (int64_t)s->max_filepos-s->read_filepos
 478         );
 479         if(s->eof) break; // file is smaller than prefill size
 480         if(stream_check_interrupt(PREFILL_SLEEP_TIME)) {
 481           res = 0;
 482           goto err_out;
 483         }
 484     }
 485     mp_msg(MSGT_CACHE,MSGL_STATUS,"\n");
 486     return 1; // parent exits
 487
 488 err_out:
 489     cache_uninit(stream);
 490     return res;
 491   }
 492
 493 #if FORKED_CACHE
 494   signal(SIGTERM,exit_sighandler); // kill
 495   cache_mainloop(s);
 496   // make sure forked code never leaves this function
 497   exit(0);
 498 #endif
 499 }
 500
 501 #if !FORKED_CACHE
 502 #if defined(__MINGW32__) || defined(__OS2__)
 503 static void ThreadProc( void *s ){
 504   cache_mainloop(s);
 505   _endthread();
 506 }
 507 #else
 508 static void *ThreadProc( void *s ){
 509   cache_mainloop(s);
 510   return NULL;
 511 }
 512 #endif
 513 #endif
 514
 515 int cache_stream_fill_buffer(stream_t *s){
 516   int len;
 517   int sector_size;
 518   if(!s->cache_pid) return stream_fill_buffer(s);
 519
 520   if(s->pos!=((cache_vars_t*)s->cache_data)->read_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"!!! read_filepos differs!!! report this bug...\n");
 521   sector_size = ((cache_vars_t*)s->cache_data)->sector_size;
 522   if (sector_size > STREAM_MAX_SECTOR_SIZE) {
 523     mp_msg(MSGT_CACHE, MSGL_ERR, "Sector size %i larger than maximum %i\n", sector_size, STREAM_MAX_SECTOR_SIZE);
 524     sector_size = STREAM_MAX_SECTOR_SIZE;
 525   }
 526
 527   len=cache_read(s->cache_data,s->buffer, sector_size);
 528   //printf("cache_stream_fill_buffer->read -> %d\n",len);
 529
 530   if(len<=0){ s->eof=1; s->buf_pos=s->buf_len=0; return 0; }
 531   s->eof=0;
 532   s->buf_pos=0;
 533   s->buf_len=len;
 534   s->pos+=len;
 535 //  printf("[%d]",len);fflush(stdout);
 536   if (s->capture_file)
 537     stream_capture_do(s);
 538   return len;
 539
 540 }
 541
 542 int cache_fill_status(stream_t *s) {
 543   cache_vars_t *cv;
 544   if (!s || !s->cache_data)
 545     return -1;
 546   cv = s->cache_data;
 547   return (cv->max_filepos-cv->read_filepos)/(cv->buffer_size / 100);
 548 }
 549
 550 int cache_stream_seek_long(stream_t *stream,off_t pos){
 551   cache_vars_t* s;
 552   off_t newpos;
 553   if(!stream->cache_pid) return stream_seek_long(stream,pos);
 554
 555   s=stream->cache_data;
 556 //  s->seek_lock=1;
 557
 558   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);
 559
 560   newpos=pos/s->sector_size; newpos*=s->sector_size; // align
 561   stream->pos=s->read_filepos=newpos;
 562   s->eof=0; // !!!!!!!
 563   cache_wakeup(stream);
 564
 565   cache_stream_fill_buffer(stream);
 566
 567   pos-=newpos;
 568   if(pos>=0 && pos<=stream->buf_len){
 569     stream->buf_pos=pos; // byte position in sector
 570     return 1;
 571   }
 572
 573 //  stream->buf_pos=stream->buf_len=0;
 574 //  return 1;
 575
 576   mp_msg(MSGT_CACHE,MSGL_V,"cache_stream_seek: WARNING! Can't seek to 0x%"PRIX64" !\n",(int64_t)(pos+newpos));
 577   return 0;
 578 }
 579
 580 int cache_do_control(stream_t *stream, int cmd, void *arg) {
 581   int sleep_count = 0;
 582   cache_vars_t* s = stream->cache_data;
 583   switch (cmd) {
 584     case STREAM_CTRL_SEEK_TO_TIME:
 585       s->control_double_arg = *(double *)arg;
 586       s->control = cmd;
 587       break;
 588     case STREAM_CTRL_SEEK_TO_CHAPTER:
 589     case STREAM_CTRL_SET_ANGLE:
 590       s->control_uint_arg = *(unsigned *)arg;
 591       s->control = cmd;
 592       break;
 593     // the core might call these every frame, so cache them...
 594     case STREAM_CTRL_GET_TIME_LENGTH:
 595       *(double *)arg = s->stream_time_length;
 596       return s->stream_time_length ? STREAM_OK : STREAM_UNSUPPORTED;
 597     case STREAM_CTRL_GET_CURRENT_TIME:
 598       *(double *)arg = s->stream_time_pos;
 599       return s->stream_time_pos != MP_NOPTS_VALUE ? STREAM_OK : STREAM_UNSUPPORTED;
 600     case STREAM_CTRL_GET_NUM_CHAPTERS:
 601     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 602     case STREAM_CTRL_GET_ASPECT_RATIO:
 603     case STREAM_CTRL_GET_NUM_ANGLES:
 604     case STREAM_CTRL_GET_ANGLE:
 605     case -2:
 606       s->control = cmd;
 607       break;
 608     default:
 609       return STREAM_UNSUPPORTED;
 610   }
 611   cache_wakeup(stream);
 612   while (s->control != -1) {
 613     if (sleep_count++ == 1000)
 614       mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not responding!\n");
 615     if (stream_check_interrupt(CONTROL_SLEEP_TIME)) {
 616       s->eof = 1;
 617       return STREAM_UNSUPPORTED;
 618     }
 619   }
 620   if (s->control_res != STREAM_OK)
 621     return s->control_res;
 622   switch (cmd) {
 623     case STREAM_CTRL_GET_TIME_LENGTH:
 624     case STREAM_CTRL_GET_CURRENT_TIME:
 625     case STREAM_CTRL_GET_ASPECT_RATIO:
 626       *(double *)arg = s->control_double_arg;
 627       break;
 628     case STREAM_CTRL_GET_NUM_CHAPTERS:
 629     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 630     case STREAM_CTRL_GET_NUM_ANGLES:
 631     case STREAM_CTRL_GET_ANGLE:
 632       *(unsigned *)arg = s->control_uint_arg;
 633       break;
 634     case STREAM_CTRL_SEEK_TO_CHAPTER:
 635     case STREAM_CTRL_SEEK_TO_TIME:
 636     case STREAM_CTRL_SET_ANGLE:
 637       stream->pos = s->read_filepos = s->control_new_pos;
 638       break;
 639   }
 640   return s->control_res;
 641 }