vb6中用zlib.dll实现压缩/解压缩字节数组

最新推荐文章于 2015-12-23 09:30:44 发布

原创最新推荐文章于 2015-12-23 09:30:44 发布 · 7.2k 阅读

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本文介绍了一种使用VBA实现的数组压缩与解压缩的方法，通过调用zlibwapi.dll库来完成数据的压缩和解压缩操作。这种方法能够有效地减少数据存储的空间需求，并提供了具体的实现代码。

(声明：魏滔序原创，转贴请注明出处。)

Option Explicit
'Declares
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" (hpvDest As Any, hpvSource As Any, ByVal cbCopy As Long)
Private Declare Function Compress Lib "zlibwapi.dll" Alias "compress" (dest As Any, destLen As Any, src As Any, ByVal srcLen As Long) As Long
Private Declare Function uncompress Lib "zlibwapi.dll" (dest As Any, destLen As Any, src As Any, ByVal srcLen As Long) As Long

Private Const OFFSET As Long = &H8

'压缩数组
Public Function CompressByte(ByteArray() As Byte) As Boolean
    Dim BufferSize As Long
    Dim TempBuffer() As Byte
    'Create a buffer to hold the compressed data
    BufferSize = UBound(ByteArray) + 1
    BufferSize = BufferSize + (BufferSize * 0.01) + 12
    ReDim TempBuffer(BufferSize)

'Compress byte array (data)
CompressByte = (Compress(TempBuffer(0), BufferSize, ByteArray(0), UBound(ByteArray) + 1) = 0)

'Add the size of the original data
Call CopyMemory(ByteArray(0), CLng(UBound(ByteArray) + 1), OFFSET)

    'Remove redundant data
    ReDim Preserve ByteArray(0 To BufferSize + OFFSET - 1)
    CopyMemory ByteArray(OFFSET), TempBuffer(0), BufferSize
End Function

'解压缩数组
Public Function UnCompressByte(ByteArray() As Byte) As Boolean
    Dim OrigLen As Long
    Dim BufferSize As Long
    Dim TempBuffer() As Byte
    'Get the original size
    Call CopyMemory(OrigLen, ByteArray(0), OFFSET)

    'Create a buffer to hold the uncompressed data
    BufferSize = OrigLen
    BufferSize = BufferSize + (BufferSize * 0.01) + 12
    ReDim TempBuffer(BufferSize)

'Decompress data
UnCompressByte = (uncompress(TempBuffer(0), BufferSize, ByteArray(OFFSET), UBound(ByteArray) - OFFSET + 1) = 0)

    'Remove redundant data
    ReDim Preserve ByteArray(0 To BufferSize - 1)
    CopyMemory ByteArray(0), TempBuffer(0), BufferSize
End Function