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56 lines
1.0 KiB
C
56 lines
1.0 KiB
C
#include "iob_internal.h"
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#ifdef __MINGW32__
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/* not supported */
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void iob_prefetch(io_batch* b,uint64 bytes) {
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(void)b;
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(void)bytes;
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}
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#else
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#include <stdio.h>
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#include <sys/types.h>
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#include <sys/mman.h>
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void iob_prefetch(io_batch* b,uint64 bytes) {
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volatile char x;
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iob_entry* e,* last;
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if (b->bytesleft==0) return;
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last=(iob_entry*)(((char*)array_start(&b->b))+array_bytes(&b->b));
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e=(iob_entry*)array_start(&b->b);
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if (!e) return;
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for (; e<last; ++e) {
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if (e->type==FROMFILE) {
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#ifdef MADV_WILLNEED
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char* c;
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c=mmap(0,bytes,PROT_READ,MAP_SHARED,e->fd,(e->offset|4095)+1);
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madvise(c,bytes,MADV_WILLNEED);
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munmap(c,bytes);
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#else
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char* c,* d;
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uint64 before=bytes;
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if (e->n<bytes) bytes=e->n;
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if (e->n>=1000000) {
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long l=e->offset&4095;
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d=c=mmap(0,bytes,PROT_READ,MAP_SHARED,e->fd,(e->offset|4095)+1);
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bytes-=l;
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if (c!=MAP_FAILED) {
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while (bytes>4095) {
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x=*d;
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bytes-=4096;
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d+=4096;
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}
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}
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munmap(c,before);
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}
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#endif
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return;
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}
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}
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(void)x;
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}
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#endif
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