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35 lines
732 B
C

#include "iob_internal.h"
#include <stdio.h>
#include <sys/mman.h>
void iob_prefetch(io_batch* b,uint64 bytes) {
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volatile char x;
iob_entry* e,* last;
if (b->bytesleft==0) return;
last=(iob_entry*)(((char*)array_start(&b->b))+array_bytes(&b->b));
e=(iob_entry*)array_start(&b->b);
if (!e) return;
for (; e<last; ++e) {
if (e->type==FROMFILE) {
char* c,* d;
uint64 before=bytes;
if (e->n<bytes) bytes=e->n;
if (e->n>=1000000) {
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long l=e->offset&4095;
d=c=mmap(0,bytes,PROT_READ,MAP_SHARED,e->fd,(e->offset|4095)+1);
bytes-=l;
if (c!=MAP_FAILED) {
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while (bytes>4095) {
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x=*d;
bytes-=4096;
d+=4096;
}
}
munmap(c,before);
}
return;
}
}
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(void)x;
}