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#include "iob_internal.h"
#ifdef __MINGW32__
/* not supported */
void iob_prefetch(io_batch* b,uint64 bytes) {
(void)b;
(void)bytes;
}
#else
#include <stdio.h>
#include <sys/types.h>
#include <sys/mman.h>
void iob_prefetch(io_batch* b,uint64 bytes) {
volatile char x=0;
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) {
#ifdef MADV_WILLNEED
char* c;
c=mmap(0,bytes,PROT_READ,MAP_SHARED,e->fd,(e->offset|4095)+1);
madvise(c,bytes,MADV_WILLNEED);
munmap(c,bytes);
#else
char* c,* d;
uint64 before=bytes;
if (e->n<bytes) bytes=e->n;
if (e->n>=1000000) {
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) {
while (bytes>4095) {
x=*d;
bytes-=4096;
d+=4096;
}
}
munmap(c,before);
}
#endif
return;
}
}
(void)x;
}
#endif
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