45 lines
1.6 KiB
VB.net
45 lines
1.6 KiB
VB.net
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)) 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 OrElse (Not pBytes(0) = 120 AndAlso Not pBytes(1) = 218) Then
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Return New MemoryStream(pBytes)
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End If
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Using compress As New MemoryStream(pBytes)
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Dim deflatMs As New MemoryStream()
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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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compress.ReadByte()
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compress.ReadByte()
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Using deflatestream As New DeflateStream(compress, CompressionMode.Decompress, False)
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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 Using
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End Function
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End Module
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End Namespace |