From 0605b2b8b356441dcab3b960504dccb2889cba5b Mon Sep 17 00:00:00 2001 From: arpi Date: Wed, 18 Jul 2001 01:28:01 +0000 Subject: Initial draft of my new cache system... git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@1342 b3059339-0415-0410-9bf9-f77b7e298cf2 --- TOOLS/cache2.c | 168 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 168 insertions(+) create mode 100644 TOOLS/cache2.c (limited to 'TOOLS') diff --git a/TOOLS/cache2.c b/TOOLS/cache2.c new file mode 100644 index 0000000000..bd2db67a36 --- /dev/null +++ b/TOOLS/cache2.c @@ -0,0 +1,168 @@ + +// gcc cache2.c ../linux/shmem.o -o cache2 + +// Initial draft of my new cache system... +// includes some simulation code, using usleep() to emulate limited bandwith +// TODO: seeking, data consistency checking + +#define READ_SPEED 20 +#define FILL_SPEED 10 + +#include +#include +#include +#include "../linux/shmem.h" + +typedef struct { + // constats: + void *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) + // Note: buffer_size should be N*sector_size, where N is integer... + int back_size; // we should keep back_size amount of old bytes for backward seek + int fill_limit; // we should fill buffer if space>fill_limit + // reader's pointers: + int read_filepos; + // filler's pointers: + int min_filepos; // buffer contain only a part of the file, from min-max pos + int max_filepos; + int offset; // filepos <-> bufferpos offset value (filepos of the buffer's first byte) + // commands/locking: + int cmd_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. +} cache_vars_t; + +int min_fill=0; +int sleep_flag=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,int size){ + int total=0; + while(size>0){ + int pos,newb,len; + + pos=s->read_filepos - s->offset; + if(pos<0) pos+=s->buffer_size; else + if(pos>=s->buffer_size) pos-=s->buffer_size; + + newb=s->max_filepos-s->read_filepos; // new bytes in the buffer + + if(newbs->buffer_size-pos) newb=s->buffer_size-pos; // handle wrap... + if(newb>size) newb=size; + + // len=write(mem,newb) + printf("Buffer read: %d bytes\n",newb); + len=newb;usleep(len*READ_SPEED*sleep_flag); + // ... + + s->read_filepos+=len; + size-=len; + total+=len; + + } + return total; +} + +int cache_fill(cache_vars_t* s){ + int read,back,newb,space,len,pos,endpos; + + read=s->read_filepos; + + // 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(spacefill_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 + + s->min_filepos=read-back; // avoid seeking-back to temp area... + + // .... + printf("Buffer fill: %d bytes of %d\n",space,s->buffer_size); + len=space; usleep(len*FILL_SPEED*sleep_flag); + // .... + + 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; + return s; +} + +int main(){ + + cache_vars_t* s=cache_init(1024*1024,2048); + +// while(cache_fill(s)){ } // fill buffer: + + min_fill=s->buffer_size; + sleep_flag=1; // start simulation + + if(fork()){ + while(1){ + if(!cache_fill(s)) usleep(10000); // wait 10ms for buffer space + //cache_stats(s); + } + } else { + srand(12345); + while(1){ + int len=10+rand()&8191; + cache_stats(s); + cache_read(s,len); + } + } + +} + -- cgit v1.2.3