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// Copyright 2011 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package index
import (
"log"
"os"
"syscall"
)
func mmapFile(f *os.File) mmapData {
st, err := f.Stat()
if err != nil {
log.Fatal(err)
}
size := st.Size()
if int64(int(size+4095)) != size+4095 {
log.Fatalf("%s: too large for mmap", f.Name())
}
n := int(size)
if n == 0 {
return mmapData{f, nil}
}
data, err := syscall.Mmap(int(f.Fd()), 0, (n+4095)&^4095, syscall.PROT_READ, syscall.MAP_SHARED)
if err != nil {
log.Fatalf("mmap %s: %v", f.Name(), err)
}
return mmapData{f, data[:n]}
}
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