35 lines
840 B
Go
35 lines
840 B
Go
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package tsdb
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import (
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"os"
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"syscall"
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"unsafe"
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)
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func mmap(f *os.File, sz int) ([]byte, error) {
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low, high := uint32(size), uint32(size>>32)
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h, errno := syscall.CreateFileMapping(syscall.Handle(f.Fd()), nil, syscall.PAGE_READONLY, low, high, nil)
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if h == 0 {
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return os.NewSyscallError("CreateFileMapping", errno)
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}
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addr, errno := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, uintptr(sz))
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if addr == 0 {
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return os.NewSyscallError("MapViewOfFile", errno)
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}
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if err := syscall.CloseHandle(syscall.Handle(h)); err != nil {
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return os.NewSyscallError("CloseHandle", err)
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}
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return (*[1 << 30]byte)(unsafe.Pointer(addr))[:sz], nil
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}
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func munmap(b []byte) error {
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if err := syscall.UnmapViewOfFile((uintptr)(unsafe.Pointer(&b[0]))); err != nil {
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return os.NewSyscallError("UnmapViewOfFile", err)
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}
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return nil
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}
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