Initial draft of my new cache system...

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@1342 b3059339-0415-0410-9bf9-f77b7e298cf2

1 files changed, 168 insertions, 0 deletions

diff --git a/TOOLS/cache2.c b/TOOLS/cache2.c
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+++ b/TOOLS/cache2.c
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+
+// 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#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(newb<min_fill) min_fill=newb; // statistics...
+
+    if(newb<=0){
+	// waiting for buffer fill...
+	usleep(10000); // 10ms
+	continue;
+    }
+    
+//    printf("*** newb: %d bytes ***\n",newb);
+    
+    if(newb>s->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(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
+  
+  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);
+    }
+  }
+
+}
+