mpv/libmpdemux/cache2.c

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#include "config.h"
#ifdef USE_STREAM_CACHE
// Initial draft of my new cache system...
// Note it runs in 2 processes (using fork()), but doesn't requires locking!!
// TODO: seeking, data consistency checking
#define READ_USLEEP_TIME 10000
#define FILL_USLEEP_TIME 50000
#define PREFILL_USLEEP_TIME 200000
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <signal.h>
#include "../linux/shmem.h"
#include "mp_msg.h"
#include "stream.h"
int stream_fill_buffer(stream_t *s);
int stream_seek_long(stream_t *s,off_t pos);
typedef struct {
// constats:
unsigned char *buffer; // base pointer of the alllocated buffer memory
int buffer_size; // size of the alllocated buffer memory
int sector_size; // size of a single sector (2048/2324)
int back_size; // we should keep back_size amount of old bytes for backward seek
int fill_limit; // we should fill buffer only if space>=fill_limit
int prefill; // we should fill min prefill bytes if cache gets empty
// filler's pointers:
int eof;
off_t min_filepos; // buffer contain only a part of the file, from min-max pos
off_t max_filepos;
off_t offset; // filepos <-> bufferpos offset value (filepos of the buffer's first byte)
// reader's pointers:
off_t read_filepos;
// commands/locking:
// int seek_lock; // 1 if we will seek/reset buffer, 2 if we are ready for cmd
// int fifo_flag; // 1 if we should use FIFO to notice cache about buffer reads.
// callback
stream_t* stream;
} cache_vars_t;
static int min_fill=0;
static int sleep_flag=0;
int cache_fill_status=0;
void cache_stats(cache_vars_t* s){
int newb=s->max_filepos-s->read_filepos; // new bytes in the buffer
printf("0x%06X [0x%06X] 0x%06X ",s->min_filepos,s->read_filepos,s->max_filepos);
printf("%3d %% (%3d%%)\n",100*newb/s->buffer_size,100*min_fill/s->buffer_size);
}
int cache_read(cache_vars_t* s,unsigned char* buf,int size){
int total=0;
while(size>0){
int pos,newb,len;
//printf("CACHE2_READ: 0x%X <= 0x%X <= 0x%X \n",s->min_filepos,s->read_filepos,s->max_filepos);
if(s->read_filepos>=s->max_filepos || s->read_filepos<s->min_filepos){
// eof?
if(s->eof) break;
// waiting for buffer fill...
usleep(READ_USLEEP_TIME); // 10ms
continue; // try again...
}
newb=s->max_filepos-s->read_filepos; // new bytes in the buffer
if(newb<min_fill) min_fill=newb; // statistics...
// printf("*** newb: %d bytes ***\n",newb);
pos=s->read_filepos - s->offset;
if(pos<0) pos+=s->buffer_size; else
if(pos>=s->buffer_size) pos-=s->buffer_size;
if(newb>s->buffer_size-pos) newb=s->buffer_size-pos; // handle wrap...
if(newb>size) newb=size;
// check:
if(s->read_filepos<s->min_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"Ehh. s->read_filepos<s->min_filepos !!! Report bug...\n");
// len=write(mem,newb)
//printf("Buffer read: %d bytes\n",newb);
memcpy(buf,&s->buffer[pos],newb);
buf+=newb;
len=newb;
// ...
s->read_filepos+=len;
size-=len;
total+=len;
}
cache_fill_status=100*(s->max_filepos-s->read_filepos)/s->buffer_size;
return total;
}
int cache_fill(cache_vars_t* s){
int back,back2,newb,space,len,pos,endpos;
off_t read=s->read_filepos;
if(read<s->min_filepos || read>s->max_filepos){
// seek...
mp_msg(MSGT_CACHE,MSGL_DBG2,"Out of boundaries... seeking to 0x%X \n",read);
s->offset= // FIXME!?
s->min_filepos=s->max_filepos=read; // drop cache content :(
if(s->stream->eof) stream_reset(s->stream);
stream_seek(s->stream,read);
mp_msg(MSGT_CACHE,MSGL_DBG2,"Seek done. new pos: 0x%X \n",(int)stream_tell(s->stream));
}
// calc number of back-bytes:
back=read - s->min_filepos;
if(back<0) back=0; // strange...
if(back>s->back_size) back=s->back_size;
// calc number of new bytes:
newb=s->max_filepos - read;
if(newb<0) newb=0; // strange...
// calc free buffer space:
space=s->buffer_size - (newb+back);
// calc bufferpos:
pos=s->max_filepos - s->offset;
if(pos>=s->buffer_size) pos-=s->buffer_size; // wrap-around
if(space<s->fill_limit){
// printf("Buffer is full (%d bytes free, limit: %d)\n",space,s->fill_limit);
return 0; // no fill...
}
// printf("### read=0x%X back=%d newb=%d space=%d pos=%d\n",read,back,newb,space,pos);
// reduce space if needed:
if(space>s->buffer_size-pos) space=s->buffer_size-pos;
// if(space>32768) space=32768; // limit one-time block size
if(space>4*s->sector_size) space=4*s->sector_size;
// if(s->seek_lock) return 0; // FIXME
#if 1
// back+newb+space <= buffer_size
back2=s->buffer_size-(space+newb); // max back size
if(s->min_filepos<(read-back2)) s->min_filepos=read-back2;
#else
s->min_filepos=read-back; // avoid seeking-back to temp area...
#endif
// ....
//printf("Buffer fill: %d bytes of %d\n",space,s->buffer_size);
//len=stream_fill_buffer(s->stream);
//memcpy(&s->buffer[pos],s->stream->buffer,len); // avoid this extra copy!
// ....
len=stream_read(s->stream,&s->buffer[pos],space);
if(!len) s->eof=1;
s->max_filepos+=len;
if(pos+len>=s->buffer_size){
// wrap...
s->offset+=s->buffer_size;
}
return len;
}
cache_vars_t* cache_init(int size,int sector){
int num;
cache_vars_t* s=shmem_alloc(sizeof(cache_vars_t));
memset(s,0,sizeof(cache_vars_t));
num=size/sector;
s->buffer_size=num*sector;
s->sector_size=sector;
s->buffer=shmem_alloc(s->buffer_size);
s->fill_limit=8*sector;
s->back_size=size/2;
s->prefill=size/20; // default: 5%
return s;
}
static void exit_sighandler(int x){
// close stream
exit(0);
}
void stream_enable_cache(stream_t *stream,int size,float prefill_init,float prefill){
int ss=(stream->type==STREAMTYPE_VCD)?VCD_SECTOR_DATA:STREAM_BUFFER_SIZE;
int min=prefill_init*size;
cache_vars_t* s=cache_init(size,ss);
stream->cache_data=s;
s->stream=stream; // callback
s->prefill=size*prefill;
if((stream->cache_pid=fork())){
// wait until cache is filled at least prefill_init %
while(s->read_filepos<s->min_filepos || s->max_filepos-s->read_filepos<min){
mp_msg(MSGT_CACHE,MSGL_STATUS,"\rCache fill: %5.2f%% (%d bytes) ",
(float)(s->max_filepos-s->read_filepos)/(float)(s->buffer_size),
s->max_filepos-s->read_filepos
);
if(s->eof) break; // file is smaller than prefill size
usleep(PREFILL_USLEEP_TIME);
}
return; // parent exits
}
// cache thread mainloop:
signal(SIGTERM,exit_sighandler); // kill
while(1){
if(!cache_fill(s)){
usleep(FILL_USLEEP_TIME); // idle
}
// cache_stats(s->cache_data);
}
}
int cache_stream_fill_buffer(stream_t *s){
int len;
if(s->eof){ s->buf_pos=s->buf_len=0; return 0; }
if(!s->cache_pid) return stream_fill_buffer(s);
// cache_stats(s->cache_data);
if(s->pos!=((cache_vars_t*)s->cache_data)->read_filepos) mp_msg(MSGT_CACHE,MSGL_ERR,"!!! read_filepos differs!!! report this bug...\n");
len=cache_read(s->cache_data,s->buffer, ((cache_vars_t*)s->cache_data)->sector_size);
//printf("cache_stream_fill_buffer->read -> %d\n",len);
if(len<=0){ s->eof=1; s->buf_pos=s->buf_len=0; return 0; }
s->buf_pos=0;
s->buf_len=len;
s->pos+=len;
// printf("[%d]",len);fflush(stdout);
return len;
}
int cache_stream_seek_long(stream_t *stream,off_t pos){
cache_vars_t* s;
off_t newpos;
if(!stream->cache_pid) return stream_seek_long(stream,pos);
s=stream->cache_data;
// s->seek_lock=1;
mp_msg(MSGT_CACHE,MSGL_DBG2,"CACHE2_SEEK: 0x%X <= 0x%X (0x%X) <= 0x%X \n",s->min_filepos,(int)pos,s->read_filepos,s->max_filepos);
newpos=pos/s->sector_size; newpos*=s->sector_size; // align
stream->pos=s->read_filepos=newpos;
s->eof=0; // !!!!!!!
cache_stream_fill_buffer(stream);
pos-=newpos;
if(pos>=0 && pos<=stream->buf_len){
stream->buf_pos=pos; // byte position in sector
return 1;
}
// stream->buf_pos=stream->buf_len=0;
// return 1;
#ifdef _LARGEFILE_SOURCE
mp_msg(MSGT_CACHE,MSGL_V,"cache_stream_seek: WARNING! Can't seek to 0x%llX !\n",(long long)(pos+newpos));
#else
mp_msg(MSGT_CACHE,MSGL_V,"cache_stream_seek: WARNING! Can't seek to 0x%X !\n",(pos+newpos));
#endif
return 0;
}
#endif