1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
|
package bolt
import (
"os"
"syscall"
"unsafe"
)
var odirect int
// fdatasync flushes written data to a file descriptor.
func fdatasync(f *os.File) error {
return f.Sync()
}
// flock acquires an advisory lock on a file descriptor.
func flock(f *os.File) error {
return nil
}
// funlock releases an advisory lock on a file descriptor.
func funlock(f *os.File) error {
return nil
}
// mmap memory maps a file to a byte slice.
// Based on: https://github.com/edsrzf/mmap-go
func mmap(f *os.File, sz int) ([]byte, error) {
// Open a file mapping handle.
sizelo, sizehi := uint32(sz>>32), uint32(sz&0xffffffff)
h, errno := syscall.CreateFileMapping(syscall.Handle(f.Fd()), nil, syscall.PAGE_READONLY, sizehi, sizelo, nil)
if h == 0 {
return nil, os.NewSyscallError("CreateFileMapping", errno)
}
// Create the memory map.
addr, errno := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, uintptr(sz))
if addr == 0 {
return nil, os.NewSyscallError("MapViewOfFile", errno)
}
// Close mapping handle.
if err := syscall.CloseHandle(syscall.Handle(h)); err != nil {
return nil, os.NewSyscallError("CloseHandle", err)
}
// Convert to a byte slice.
b := ((*[0xFFFFFFF]byte)(unsafe.Pointer(addr)))[0:sz]
return b, nil
}
// munmap unmaps a pointer from a file.
// Based on: https://github.com/edsrzf/mmap-go
func munmap(b []byte) error {
addr := (uintptr)(unsafe.Pointer(&b[0]))
if err := syscall.UnmapViewOfFile(addr); err != nil {
return os.NewSyscallError("UnmapViewOfFile", err)
}
return nil
}
|
