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 // Initial draft of my new cache system...
  20 // Note it runs in 2 processes (using fork()), but doesn't require locking!!
  21 // TODO: seeking, data consistency checking
  22
  23 #define READ_SLEEP_TIME 10
  24 // These defines are used to reduce the cost of many successive
  25 // seeks (e.g. when a file has no index) by spinning quickly at first.
  26 #define INITIAL_FILL_USLEEP_TIME 1000
  27 #define INITIAL_FILL_USLEEP_COUNT 10
  28 #define FILL_USLEEP_TIME 50000
  29 #define PREFILL_SLEEP_TIME 200
  30 #define CONTROL_SLEEP_TIME 0
  31
  32 #include <stdio.h>
  33 #include <stdlib.h>
  34 #include <string.h>
  35 #include <signal.h>
  36 #include <sys/types.h>
  37 #include <unistd.h>
  38 #include <errno.h>
  39
  40 #include <libavutil/common.h>
  41
  42 #include "config.h"
  43
  44 #include "osdep/shmem.h"
  45 #include "osdep/timer.h"
  46 #if defined(__MINGW32__)
  47 #include <windows.h>
  48 static void ThreadProc( void *s );
  49 #elif defined(PTHREAD_CACHE)
  50 #include <pthread.h>
  51 static void *ThreadProc(void *s);
  52 #else
  53 #include <sys/wait.h>
  54 #define FORKED_CACHE 1
  55 #endif
  56 #ifndef FORKED_CACHE
  57 #define FORKED_CACHE 0
  58 #endif
  59
  60 #include "mp_msg.h"
  61
  62 #include "stream.h"
  63 #include "cache2.h"
  64 #include "mpcommon.h"
  65
  66 typedef struct {
  67   // constats:
  68   unsigned char *buffer;      // base pointer of the allocated buffer memory
  69   int buffer_size; // size of the allocated buffer memory
  70   int sector_size; // size of a single sector (2048/2324)
  71   int back_size;   // we should keep back_size amount of old bytes for backward seek
  72   int fill_limit;  // we should fill buffer only if space>=fill_limit
  73   int seek_limit;  // keep filling cache if distance is less that seek limit
  74   // filler's pointers:
  75   int eof;
  76   off_t min_filepos; // buffer contain only a part of the file, from min-max pos
  77   off_t max_filepos;
  78   off_t offset;      // filepos <-> bufferpos  offset value (filepos of the buffer's first byte)
  79   // reader's pointers:
  80   off_t read_filepos;
  81   // commands/locking:
  82 //  int seek_lock;   // 1 if we will seek/reset buffer, 2 if we are ready for cmd
  83 //  int fifo_flag;  // 1 if we should use FIFO to notice cache about buffer reads.
  84   // callback
  85   stream_t* stream;
  86   volatile int control;
  87   volatile unsigned control_uint_arg;
  88   volatile double control_double_arg;
  89   volatile int control_res;
  90   volatile off_t control_new_pos;
  91   volatile double stream_time_length;
  92   volatile double stream_time_pos;
  93 } cache_vars_t;
  94
  95 static int min_fill=0;
  96
  97 static void cache_wakeup(stream_t *s)
  98 {
  99 #if FORKED_CACHE
 100   // signal process to wake up immediately
 101   kill(s->cache_pid, SIGUSR1);
 102 #endif
 103 }
 104
 105 static int cache_read(cache_vars_t *s, unsigned char *buf, int size)
 106 {
 107   int total=0;
 108   int sleep_count = 0;
 109   int last_max = s->max_filepos;
 110   while(size>0){
 111     int pos,newb,len;
 112
 113   //printf("CACHE2_READ: 0x%X <= 0x%X <= 0x%X  \n",s->min_filepos,s->read_filepos,s->max_filepos);
 114
 115     if(s->read_filepos>=s->max_filepos || s->read_filepos<s->min_filepos){
 116         // eof?
 117         if(s->eof) break;
 118         if (s->max_filepos == last_max) {
 119             if (sleep_count++ == 10)
 120                 mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not filling, consider increasing -cache and/or -cache-min!\n");
 121         } else {
 122             last_max = s->max_filepos;
 123             sleep_count = 0;
 124         }
 125         // waiting for buffer fill...
 126         if (stream_check_interrupt(READ_SLEEP_TIME)) {
 127             s->eof = 1;
 128             break;
 129         }
 130         continue; // try again...
 131     }
 132     sleep_count = 0;
 133
 134     newb=s->max_filepos-s->read_filepos; // new bytes in the buffer
 135     if(newb<min_fill) min_fill=newb; // statistics...
 136
 137 //    printf("*** newb: %d bytes ***\n",newb);
 138
 139     pos=s->read_filepos - s->offset;
 140     if(pos<0) pos+=s->buffer_size; else
 141     if(pos>=s->buffer_size) pos-=s->buffer_size;
 142
 143     if(newb>s->buffer_size-pos) newb=s->buffer_size-pos; // handle wrap...
 144     if(newb>size) newb=size;
 145
 146     // check:
 147     if(s->read_filepos<s->min_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"Ehh. s->read_filepos<s->min_filepos !!! Report bug...\n");
 148
 149     // len=write(mem,newb)
 150     //printf("Buffer read: %d bytes\n",newb);
 151     memcpy(buf,&s->buffer[pos],newb);
 152     buf+=newb;
 153     len=newb;
 154     // ...
 155
 156     s->read_filepos+=len;
 157     size-=len;
 158     total+=len;
 159
 160   }
 161   return total;
 162 }
 163
 164 static int cache_fill(cache_vars_t *s)
 165 {
 166   int back,back2,newb,space,len,pos;
 167   off_t read=s->read_filepos;
 168   int read_chunk;
 169   int wraparound_copy = 0;
 170
 171   if(read<s->min_filepos || read>s->max_filepos){
 172       // seek...
 173       mp_msg(MSGT_CACHE,MSGL_DBG2,"Out of boundaries... seeking to 0x%"PRIX64"  \n",(int64_t)read);
 174       // drop cache contents only if seeking backward or too much fwd.
 175       // This is also done for on-disk files, since it loses the backseek cache.
 176       // That in turn can cause major bandwidth increase and performance
 177       // issues with e.g. mov or badly interleaved files
 178       if(read<s->min_filepos || read>=s->max_filepos+s->seek_limit)
 179       {
 180         s->offset= // FIXME!?
 181         s->min_filepos=s->max_filepos=read; // drop cache content :(
 182         if(s->stream->eof) stream_reset(s->stream);
 183         stream_seek_internal(s->stream,read);
 184         mp_msg(MSGT_CACHE,MSGL_DBG2,"Seek done. new pos: 0x%"PRIX64"  \n",(int64_t)stream_tell(s->stream));
 185       }
 186   }
 187
 188   // calc number of back-bytes:
 189   back=read - s->min_filepos;
 190   if(back<0) back=0; // strange...
 191   if(back>s->back_size) back=s->back_size;
 192
 193   // calc number of new bytes:
 194   newb=s->max_filepos - read;
 195   if(newb<0) newb=0; // strange...
 196
 197   // calc free buffer space:
 198   space=s->buffer_size - (newb+back);
 199
 200   // calc bufferpos:
 201   pos=s->max_filepos - s->offset;
 202   if(pos>=s->buffer_size) pos-=s->buffer_size; // wrap-around
 203
 204   if(space<s->fill_limit){
 205 //    printf("Buffer is full (%d bytes free, limit: %d)\n",space,s->fill_limit);
 206     return 0; // no fill...
 207   }
 208
 209 //  printf("### read=0x%X  back=%d  newb=%d  space=%d  pos=%d\n",read,back,newb,space,pos);
 210
 211   // try to avoid wrap-around. If not possible due to sector size
 212   // do an extra copy.
 213   if(space>s->buffer_size-pos) {
 214     if (s->buffer_size-pos >= s->sector_size) {
 215       space=s->buffer_size-pos;
 216     } else {
 217       space = s->sector_size;
 218       wraparound_copy = 1;
 219     }
 220   }
 221
 222   // limit one-time block size
 223   read_chunk = s->stream->read_chunk;
 224   if (!read_chunk) read_chunk = 4*s->sector_size;
 225   space = FFMIN(space, read_chunk);
 226
 227 #if 1
 228   // back+newb+space <= buffer_size
 229   back2=s->buffer_size-(space+newb); // max back size
 230   if(s->min_filepos<(read-back2)) s->min_filepos=read-back2;
 231 #else
 232   s->min_filepos=read-back; // avoid seeking-back to temp area...
 233 #endif
 234
 235   if (wraparound_copy) {
 236     int to_copy;
 237     len = stream_read_internal(s->stream, s->stream->buffer, space);
 238     to_copy = FFMIN(len, s->buffer_size-pos);
 239     memcpy(s->buffer + pos, s->stream->buffer, to_copy);
 240     memcpy(s->buffer, s->stream->buffer + to_copy, len - to_copy);
 241   } else
 242   len = stream_read_internal(s->stream, &s->buffer[pos], space);
 243   s->eof= !len;
 244
 245   s->max_filepos+=len;
 246   if(pos+len>=s->buffer_size){
 247       // wrap...
 248       s->offset+=s->buffer_size;
 249   }
 250
 251   return len;
 252
 253 }
 254
 255 static int cache_execute_control(cache_vars_t *s) {
 256   double double_res;
 257   unsigned uint_res;
 258   static unsigned last;
 259   int quit = s->control == -2;
 260   if (quit || !s->stream->control) {
 261     s->stream_time_length = 0;
 262     s->stream_time_pos = MP_NOPTS_VALUE;
 263     s->control_new_pos = 0;
 264     s->control_res = STREAM_UNSUPPORTED;
 265     s->control = -1;
 266     return !quit;
 267   }
 268   if (GetTimerMS() - last > 99) {
 269     double len, pos;
 270     if (s->stream->control(s->stream, STREAM_CTRL_GET_TIME_LENGTH, &len) == STREAM_OK)
 271       s->stream_time_length = len;
 272     else
 273       s->stream_time_length = 0;
 274     if (s->stream->control(s->stream, STREAM_CTRL_GET_CURRENT_TIME, &pos) == STREAM_OK)
 275       s->stream_time_pos = pos;
 276     else
 277       s->stream_time_pos = MP_NOPTS_VALUE;
 278     last = GetTimerMS();
 279   }
 280   if (s->control == -1) return 1;
 281   switch (s->control) {
 282     case STREAM_CTRL_SEEK_TO_TIME:
 283       double_res = s->control_double_arg;
 284     case STREAM_CTRL_GET_CURRENT_TIME:
 285     case STREAM_CTRL_GET_ASPECT_RATIO:
 286       s->control_res = s->stream->control(s->stream, s->control, &double_res);
 287       s->control_double_arg = double_res;
 288       break;
 289     case STREAM_CTRL_SEEK_TO_CHAPTER:
 290     case STREAM_CTRL_SET_ANGLE:
 291       uint_res = s->control_uint_arg;
 292     case STREAM_CTRL_GET_NUM_CHAPTERS:
 293     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 294     case STREAM_CTRL_GET_NUM_ANGLES:
 295     case STREAM_CTRL_GET_ANGLE:
 296       s->control_res = s->stream->control(s->stream, s->control, &uint_res);
 297       s->control_uint_arg = uint_res;
 298       break;
 299     default:
 300       s->control_res = STREAM_UNSUPPORTED;
 301       break;
 302   }
 303   s->control_new_pos = s->stream->pos;
 304   s->control = -1;
 305   return 1;
 306 }
 307
 308 static void *shared_alloc(int size) {
 309 #if FORKED_CACHE
 310     return shmem_alloc(size);
 311 #else
 312     return malloc(size);
 313 #endif
 314 }
 315
 316 static void shared_free(void *ptr, int size) {
 317 #if FORKED_CACHE
 318     shmem_free(ptr, size);
 319 #else
 320     free(ptr);
 321 #endif
 322 }
 323
 324 static cache_vars_t* cache_init(int size,int sector){
 325   int num;
 326   cache_vars_t* s=shared_alloc(sizeof(cache_vars_t));
 327   if(s==NULL) return NULL;
 328
 329   memset(s,0,sizeof(cache_vars_t));
 330   num=size/sector;
 331   if(num < 16){
 332      num = 16;
 333   }//32kb min_size
 334   s->buffer_size=num*sector;
 335   s->sector_size=sector;
 336   s->buffer=shared_alloc(s->buffer_size);
 337
 338   if(s->buffer == NULL){
 339     shared_free(s, sizeof(cache_vars_t));
 340     return NULL;
 341   }
 342
 343   s->fill_limit=8*sector;
 344   s->back_size=s->buffer_size/2;
 345   return s;
 346 }
 347
 348 void cache_uninit(stream_t *s) {
 349   cache_vars_t* c = s->cache_data;
 350   if(s->cache_pid) {
 351 #if !FORKED_CACHE
 352     cache_do_control(s, -2, NULL);
 353 #else
 354     kill(s->cache_pid,SIGKILL);
 355     waitpid(s->cache_pid,NULL,0);
 356 #endif
 357     s->cache_pid = 0;
 358   }
 359   if(!c) return;
 360   shared_free(c->buffer, c->buffer_size);
 361   c->buffer = NULL;
 362   c->stream = NULL;
 363   shared_free(s->cache_data, sizeof(cache_vars_t));
 364   s->cache_data = NULL;
 365 }
 366
 367 #if FORKED_CACHE
 368 static void exit_sighandler(int x){
 369   // close stream
 370   exit(0);
 371 }
 372
 373 static void dummy_sighandler(int x) {
 374 }
 375 #endif
 376
 377 /**
 378  * Main loop of the cache process or thread.
 379  */
 380 static void cache_mainloop(cache_vars_t *s) {
 381     int sleep_count = 0;
 382 #if FORKED_CACHE
 383     struct sigaction sa = { .sa_handler = SIG_IGN };
 384     sigaction(SIGUSR1, &sa, NULL);
 385 #endif
 386     do {
 387         if (!cache_fill(s)) {
 388 #if FORKED_CACHE
 389             // Let signal wake us up, we cannot leave this
 390             // enabled since we do not handle EINTR in most places.
 391             // This might need extra code to work on BSD.
 392             sa.sa_handler = dummy_sighandler;
 393             sigaction(SIGUSR1, &sa, NULL);
 394 #endif
 395             if (sleep_count < INITIAL_FILL_USLEEP_COUNT) {
 396                 sleep_count++;
 397                 usec_sleep(INITIAL_FILL_USLEEP_TIME);
 398             } else
 399                 usec_sleep(FILL_USLEEP_TIME); // idle
 400 #if FORKED_CACHE
 401             sa.sa_handler = SIG_IGN;
 402             sigaction(SIGUSR1, &sa, NULL);
 403 #endif
 404         } else
 405             sleep_count = 0;
 406     } while (cache_execute_control(s));
 407 }
 408
 409 int stream_enable_cache_percent(stream_t *stream, int stream_cache_size,
 410     float stream_cache_min_percent, float stream_cache_seek_min_percent)
 411 {
 412     return stream_enable_cache(stream, stream_cache_size * 1024,
 413         stream_cache_size * 1024 * (stream_cache_min_percent / 100.0),
 414         stream_cache_size * 1024 * (stream_cache_seek_min_percent / 100.0));
 415 }
 416
 417 /**
 418  * \return 1 on success, 0 if the function was interrupted and -1 on error
 419  */
 420 int stream_enable_cache(stream_t *stream,int size,int min,int seek_limit){
 421   int ss = stream->sector_size ? stream->sector_size : STREAM_BUFFER_SIZE;
 422   int res = -1;
 423   cache_vars_t* s;
 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 #else
 457     {
 458     pthread_t tid;
 459     pthread_create(&tid, NULL, ThreadProc, s);
 460     stream->cache_pid = 1;
 461     }
 462 #endif
 463 #endif
 464     if (!stream->cache_pid) {
 465         mp_msg(MSGT_CACHE, MSGL_ERR,
 466                "Starting cache process/thread failed: %s.\n", strerror(errno));
 467         goto err_out;
 468     }
 469     // wait until cache is filled at least prefill_init %
 470     mp_msg(MSGT_CACHE,MSGL_V,"CACHE_PRE_INIT: %"PRId64" [%"PRId64"] %"PRId64"  pre:%d  eof:%d  \n",
 471         (int64_t)s->min_filepos,(int64_t)s->read_filepos,(int64_t)s->max_filepos,min,s->eof);
 472     while(s->read_filepos<s->min_filepos || s->max_filepos-s->read_filepos<min){
 473         mp_tmsg(MSGT_CACHE,MSGL_STATUS,"\rCache fill: %5.2f%% (%"PRId64" bytes)   ",
 474             100.0*(float)(s->max_filepos-s->read_filepos)/(float)(s->buffer_size),
 475             (int64_t)s->max_filepos-s->read_filepos
 476         );
 477         if(s->eof) break; // file is smaller than prefill size
 478         if(stream_check_interrupt(PREFILL_SLEEP_TIME)) {
 479           res = 0;
 480           goto err_out;
 481         }
 482     }
 483     mp_msg(MSGT_CACHE,MSGL_STATUS,"\n");
 484     return 1; // parent exits
 485
 486 err_out:
 487     cache_uninit(stream);
 488     return res;
 489   }
 490
 491 #if FORKED_CACHE
 492   signal(SIGTERM,exit_sighandler); // kill
 493   cache_mainloop(s);
 494   // make sure forked code never leaves this function
 495   exit(0);
 496 #endif
 497 }
 498
 499 #if !FORKED_CACHE
 500 #if defined(__MINGW32__)
 501 static void ThreadProc( void *s ){
 502   cache_mainloop(s);
 503   _endthread();
 504 }
 505 #else
 506 static void *ThreadProc( void *s ){
 507   cache_mainloop(s);
 508   return NULL;
 509 }
 510 #endif
 511 #endif
 512
 513 int cache_stream_fill_buffer(stream_t *s){
 514   int len;
 515   int sector_size;
 516   if(!s->cache_pid) return stream_fill_buffer(s);
 517
 518   if(s->pos!=((cache_vars_t*)s->cache_data)->read_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"!!! read_filepos differs!!! report this bug...\n");
 519   sector_size = ((cache_vars_t*)s->cache_data)->sector_size;
 520   if (sector_size > STREAM_MAX_SECTOR_SIZE) {
 521     mp_msg(MSGT_CACHE, MSGL_ERR, "Sector size %i larger than maximum %i\n", sector_size, STREAM_MAX_SECTOR_SIZE);
 522     sector_size = STREAM_MAX_SECTOR_SIZE;
 523   }
 524
 525   len=cache_read(s->cache_data,s->buffer, sector_size);
 526   //printf("cache_stream_fill_buffer->read -> %d\n",len);
 527
 528   if(len<=0){ s->eof=1; s->buf_pos=s->buf_len=0; return 0; }
 529   s->eof=0;
 530   s->buf_pos=0;
 531   s->buf_len=len;
 532   s->pos+=len;
 533 //  printf("[%d]",len);fflush(stdout);
 534   if (s->capture_file)
 535     stream_capture_do(s);
 536   return len;
 537
 538 }
 539
 540 int cache_fill_status(stream_t *s) {
 541   cache_vars_t *cv;
 542   if (!s || !s->cache_data)
 543     return -1;
 544   cv = s->cache_data;
 545   return (cv->max_filepos-cv->read_filepos)/(cv->buffer_size / 100);
 546 }
 547
 548 int cache_stream_seek_long(stream_t *stream,off_t pos){
 549   cache_vars_t* s;
 550   off_t newpos;
 551   if(!stream->cache_pid) return stream_seek_long(stream,pos);
 552
 553   s=stream->cache_data;
 554 //  s->seek_lock=1;
 555
 556   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);
 557
 558   newpos=pos/s->sector_size; newpos*=s->sector_size; // align
 559   stream->pos=s->read_filepos=newpos;
 560   s->eof=0; // !!!!!!!
 561   cache_wakeup(stream);
 562
 563   cache_stream_fill_buffer(stream);
 564
 565   pos-=newpos;
 566   if(pos>=0 && pos<=stream->buf_len){
 567     stream->buf_pos=pos; // byte position in sector
 568     return 1;
 569   }
 570
 571 //  stream->buf_pos=stream->buf_len=0;
 572 //  return 1;
 573
 574   mp_msg(MSGT_CACHE,MSGL_V,"cache_stream_seek: WARNING! Can't seek to 0x%"PRIX64" !\n",(int64_t)(pos+newpos));
 575   return 0;
 576 }
 577
 578 int cache_do_control(stream_t *stream, int cmd, void *arg) {
 579   int sleep_count = 0;
 580   cache_vars_t* s = stream->cache_data;
 581   switch (cmd) {
 582     case STREAM_CTRL_SEEK_TO_TIME:
 583       s->control_double_arg = *(double *)arg;
 584       s->control = cmd;
 585       break;
 586     case STREAM_CTRL_SEEK_TO_CHAPTER:
 587     case STREAM_CTRL_SET_ANGLE:
 588       s->control_uint_arg = *(unsigned *)arg;
 589       s->control = cmd;
 590       break;
 591     // the core might call these every frame, so cache them...
 592     case STREAM_CTRL_GET_TIME_LENGTH:
 593       *(double *)arg = s->stream_time_length;
 594       return s->stream_time_length ? STREAM_OK : STREAM_UNSUPPORTED;
 595     case STREAM_CTRL_GET_CURRENT_TIME:
 596       *(double *)arg = s->stream_time_pos;
 597       return s->stream_time_pos != MP_NOPTS_VALUE ? STREAM_OK : STREAM_UNSUPPORTED;
 598     case STREAM_CTRL_GET_NUM_CHAPTERS:
 599     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 600     case STREAM_CTRL_GET_ASPECT_RATIO:
 601     case STREAM_CTRL_GET_NUM_ANGLES:
 602     case STREAM_CTRL_GET_ANGLE:
 603     case -2:
 604       s->control = cmd;
 605       break;
 606     default:
 607       return STREAM_UNSUPPORTED;
 608   }
 609   cache_wakeup(stream);
 610   while (s->control != -1) {
 611     if (sleep_count++ == 1000)
 612       mp_msg(MSGT_CACHE, MSGL_WARN, "Cache not responding!\n");
 613     if (stream_check_interrupt(CONTROL_SLEEP_TIME)) {
 614       s->eof = 1;
 615       return STREAM_UNSUPPORTED;
 616     }
 617   }
 618   if (s->control_res != STREAM_OK)
 619     return s->control_res;
 620   switch (cmd) {
 621     case STREAM_CTRL_GET_TIME_LENGTH:
 622     case STREAM_CTRL_GET_CURRENT_TIME:
 623     case STREAM_CTRL_GET_ASPECT_RATIO:
 624       *(double *)arg = s->control_double_arg;
 625       break;
 626     case STREAM_CTRL_GET_NUM_CHAPTERS:
 627     case STREAM_CTRL_GET_CURRENT_CHAPTER:
 628     case STREAM_CTRL_GET_NUM_ANGLES:
 629     case STREAM_CTRL_GET_ANGLE:
 630       *(unsigned *)arg = s->control_uint_arg;
 631       break;
 632     case STREAM_CTRL_SEEK_TO_CHAPTER:
 633     case STREAM_CTRL_SEEK_TO_TIME:
 634     case STREAM_CTRL_SET_ANGLE:
 635       stream->pos = s->read_filepos = s->control_new_pos;
 636       break;
 637   }
 638   return s->control_res;
 639 }