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30 lines
633 B
C
30 lines
633 B
C
21 years ago
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#include "iob_internal.h"
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#include <stdio.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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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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char* c,* d;
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if (e->n>=1000000) {
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d=c=mmap(0,bytes,PROT_READ,MAP_SHARED,e->fd,(e->offset|4095)+1);
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if (c!=MAP_FAILED) {
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while (bytes>4096) {
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volatile char x=*d;
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bytes-=4096;
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d+=4096;
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(void)x;
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}
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}
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munmap(c,bytes);
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}
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return;
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}
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}
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}
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