microsoft-visualbasic-runtime/CommandLine/Stream.vb

56 lines
2.2 KiB
VB.net

Imports System.IO
Imports System.IO.MemoryMappedFiles
Namespace CommandLine
Public Enum FileTypes
DiskFile
PipelineFile
MemoryFile
End Enum
''' <summary>
''' + file path: C://path/to/file
''' + standard input: std_in://
''' + standard output: std_out://
''' + memory mapping file: memory://file/uri
''' </summary>
Public Module StreamExtensions
Public Function FileType(reference As String) As FileTypes
If reference.TextEquals("std_in://") OrElse reference.TextEquals("std_out://") Then
Return FileTypes.PipelineFile
ElseIf reference.ToLower.StartsWith("memory://") Then
Return FileTypes.MemoryFile
Else
Return FileTypes.DiskFile
End If
End Function
Public Function OpenForRead(reference As String) As Stream
If reference.TextEquals("std_in://") Then
Return Console.OpenStandardInput
ElseIf reference.TextEquals("std_out://") Then
Throw New InvalidProgramException()
ElseIf reference.ToLower.StartsWith("memory://") Then
reference = reference.GetTagValue(":/").Value
Return MemoryMappedFile.OpenExisting(reference).CreateViewStream
Else
Return New FileStream(reference, FileMode.Open, access:=FileAccess.Read, share:=FileShare.ReadWrite)
End If
End Function
Public Function OpenForWrite(reference As String, Optional size& = 1024 * 1024 * 1024) As Stream
If reference.TextEquals("std_in://") Then
Throw New InvalidProgramException
ElseIf reference.TextEquals("std_out://") Then
Return Console.OpenStandardOutput
ElseIf reference.ToLower.StartsWith("memory://") Then
reference = reference.GetTagValue(":/").Value
Return MemoryMappedFile.CreateOrOpen(reference, size).CreateViewStream
Else
Return New FileStream(reference, FileMode.OpenOrCreate, access:=FileAccess.Write, share:=FileShare.Read)
End If
End Function
End Module
End Namespace