diff options
Diffstat (limited to 'vendor/github.com/Azure/azure-storage-blob-go/2018-03-28/azblob/zc_mmf_windows.go')
-rw-r--r-- | vendor/github.com/Azure/azure-storage-blob-go/2018-03-28/azblob/zc_mmf_windows.go | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/vendor/github.com/Azure/azure-storage-blob-go/2018-03-28/azblob/zc_mmf_windows.go b/vendor/github.com/Azure/azure-storage-blob-go/2018-03-28/azblob/zc_mmf_windows.go new file mode 100644 index 000000000..1a6e83dad --- /dev/null +++ b/vendor/github.com/Azure/azure-storage-blob-go/2018-03-28/azblob/zc_mmf_windows.go @@ -0,0 +1,38 @@ +package azblob + +import ( + "os" + "reflect" + "syscall" + "unsafe" +) + +type mmf []byte + +func newMMF(file *os.File, writable bool, offset int64, length int) (mmf, error) { + prot, access := uint32(syscall.PAGE_READONLY), uint32(syscall.FILE_MAP_READ) // Assume read-only + if writable { + prot, access = uint32(syscall.PAGE_READWRITE), uint32(syscall.FILE_MAP_WRITE) + } + hMMF, errno := syscall.CreateFileMapping(syscall.Handle(file.Fd()), nil, prot, uint32(int64(length)>>32), uint32(int64(length)&0xffffffff), nil) + if hMMF == 0 { + return nil, os.NewSyscallError("CreateFileMapping", errno) + } + defer syscall.CloseHandle(hMMF) + addr, errno := syscall.MapViewOfFile(hMMF, access, uint32(offset>>32), uint32(offset&0xffffffff), uintptr(length)) + m := mmf{} + h := (*reflect.SliceHeader)(unsafe.Pointer(&m)) + h.Data = addr + h.Len = length + h.Cap = h.Len + return m, nil +} + +func (m *mmf) unmap() { + addr := uintptr(unsafe.Pointer(&(([]byte)(*m)[0]))) + *m = mmf{} + err := syscall.UnmapViewOfFile(addr) + if err != nil { + panic(err) + } +} |