109 lines
3.8 KiB
VB.net
109 lines
3.8 KiB
VB.net
#Region "Microsoft.VisualBasic::2bc81f82cf1a26d06e4d18edad34ebe8, Microsoft.VisualBasic.Core\Net\HTTP\Stream\ZipStream.vb"
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' Author:
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'
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' asuka (amethyst.asuka@gcmodeller.org)
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' xie (genetics@smrucc.org)
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' xieguigang (xie.guigang@live.com)
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'
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' Copyright (c) 2018 GPL3 Licensed
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'
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'
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' GNU GENERAL PUBLIC LICENSE (GPL3)
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'
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'
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' This program is free software: you can redistribute it and/or modify
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' it under the terms of the GNU General Public License as published by
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' the Free Software Foundation, either version 3 of the License, or
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' (at your option) any later version.
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'
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' This program is distributed in the hope that it will be useful,
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' but WITHOUT ANY WARRANTY; without even the implied warranty of
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' MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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' GNU General Public License for more details.
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'
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' You should have received a copy of the GNU General Public License
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' along with this program. If not, see <http://www.gnu.org/licenses/>.
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' /********************************************************************************/
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' Summaries:
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' Module ZipStreamExtensions
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'
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' Function: Deflate, UnZipStream
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'
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'
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' /********************************************************************************/
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#End Region
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Imports System.IO
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Imports System.IO.Compression
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Imports System.Runtime.CompilerServices
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Imports Microsoft.VisualBasic.Linq
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Namespace Net.Http
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Public Module ZipStreamExtensions
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''' <summary>
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''' 进行zlib数据流的zip解压缩
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'''
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''' > https://bbs.csdn.net/topics/392275364
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''' </summary>
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''' <param name="stream"></param>
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''' <returns></returns>
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''' <remarks>
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''' ###### 2018-11-15 经过测试，没有bug，与zlibnet的测试结果一致
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''' </remarks>
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<Extension>
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Public Function UnZipStream(stream As IEnumerable(Of Byte), Optional noMagic As Boolean = False) As MemoryStream
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Dim pBytes = stream.SafeQuery.ToArray
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' Deflate 算法压缩之后的数据，第一个字节是 78h（120b），第二个字节是 DAh(218b)
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If pBytes.Length < 2 Then
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Return New MemoryStream(pBytes)
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ElseIf (Not pBytes(0) = 120 AndAlso Not pBytes(1) = 218) Then
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If noMagic Then
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' 最开始的两个字节不是magic标记
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' 并且也指定了没有magic头的参数选项
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' 在这里直接尝试解压缩
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Using compress As New MemoryStream(pBytes)
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Return compress.Deflate
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End Using
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Else
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Return New MemoryStream(pBytes)
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End If
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End If
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Using compress As New MemoryStream(pBytes)
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' 先读取前两个deflate压缩算法标识字节，然后才能用deflateStream解压
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' 这个行为与 zlib库、sharpZiplib库等不同（这些库都是直接传入解压）
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Call compress.ReadByte()
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Call compress.ReadByte()
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Return compress.Deflate
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End Using
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End Function
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''' <summary>
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''' 在这里应该是正确的跳过了deflate压缩算法标识字节的数据流
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''' </summary>
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''' <returns></returns>
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<Extension>
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Public Function Deflate(compress As Stream) As MemoryStream
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Dim deflatMs As New MemoryStream()
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Using deflatestream As New DeflateStream(compress, CompressionMode.Decompress)
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deflatestream.CopyTo(deflatMs, 8192)
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End Using
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Return deflatMs
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End Function
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End Module
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End Namespace
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