mirror of
https://gitlab.com/pulsechaincom/erigon-pulse.git
synced 2024-12-25 13:07:17 +00:00
69 lines
2.0 KiB
Go
69 lines
2.0 KiB
Go
/*
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Copyright 2021 Erigon contributors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package mmap
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import (
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"os"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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const MaxMapSize = 0xFFFFFFFFFFFF
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func Mmap(f *os.File, size int) ([]byte, *[MaxMapSize]byte, error) {
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// Open a file mapping handle.
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sizelo := uint32(size >> 32)
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sizehi := uint32(size) & 0xffffffff
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h, errno := windows.CreateFileMapping(windows.Handle(f.Fd()), nil, windows.PAGE_READONLY, sizelo, sizehi, nil)
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if h == 0 {
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return nil, nil, os.NewSyscallError("CreateFileMapping", errno)
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}
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// Create the memory map.
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addr, errno := windows.MapViewOfFile(h, windows.FILE_MAP_READ, 0, 0, uintptr(size))
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if addr == 0 {
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return nil, nil, os.NewSyscallError("MapViewOfFile", errno)
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}
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// Close mapping handle.
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if err := windows.CloseHandle(windows.Handle(h)); err != nil {
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return nil, nil, os.NewSyscallError("CloseHandle", err)
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}
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// Convert to a byte array.
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mmapHandle2 := ((*[MaxMapSize]byte)(unsafe.Pointer(addr)))
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return mmapHandle2[:size], mmapHandle2, nil
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}
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func MadviseSequential(mmapHandle1 []byte) error { return nil }
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func MadviseNormal(mmapHandle1 []byte) error { return nil }
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func MadviseWillNeed(mmapHandle1 []byte) error { return nil }
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func MadviseRandom(mmapHandle1 []byte) error { return nil }
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func Munmap(_ []byte, mmapHandle2 *[MaxMapSize]byte) error {
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if mmapHandle2 == nil {
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return nil
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}
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addr := (uintptr)(unsafe.Pointer(&mmapHandle2[0]))
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if err := windows.UnmapViewOfFile(addr); 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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