| // 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 mmap |
| |
| import ( |
| "fmt" |
| "os" |
| "syscall" |
| "unsafe" |
| |
| "internal/syscall/windows" |
| ) |
| |
| func mmapFile(f *os.File) (Data, error) { |
| st, err := f.Stat() |
| if err != nil { |
| return Data{}, err |
| } |
| size := st.Size() |
| if size == 0 { |
| return Data{f, nil}, nil |
| } |
| h, err := syscall.CreateFileMapping(syscall.Handle(f.Fd()), nil, syscall.PAGE_READONLY, 0, 0, nil) |
| if err != nil { |
| return Data{}, fmt.Errorf("CreateFileMapping %s: %w", f.Name(), err) |
| } |
| |
| addr, err := syscall.MapViewOfFile(h, syscall.FILE_MAP_READ, 0, 0, 0) |
| if err != nil { |
| return Data{}, fmt.Errorf("MapViewOfFile %s: %w", f.Name(), err) |
| } |
| var info windows.MemoryBasicInformation |
| err = windows.VirtualQuery(addr, &info, unsafe.Sizeof(info)) |
| if err != nil { |
| return Data{}, fmt.Errorf("VirtualQuery %s: %w", f.Name(), err) |
| } |
| data := unsafe.Slice((*byte)(unsafe.Pointer(addr)), int(info.RegionSize)) |
| return Data{f, data}, nil |
| } |