) As Long
Dim fl As Long
If m_LastBuff = False Then
If m_OffSet = MAX_FILE_BUFF Then
fl = ReadFileToBuff
Select Case fl
Case 0
GetByte = 0
Case -1
GetByte = -1
Case Else
ch = m_fb(0)
m_OffSet = 1
GetByte = 1
End Select
Else
ch = m_fb(m_OffSet)
m_OffSet = m_OffSet + 1
GetByte = 1
End If
Else
If m_OffSet < m_MaxBytes Then
ch = m_fb(m_OffSet)
m_OffSet = m_OffSet + 1
GetByte = 1
Else
ch = EOF_CHAR
GetByte = 0
End If
End If
End Function
''''写一个字节,如果正确表示1，错误为-1
Public Function PutByte(by As Byte) As Long
If m_OffSet < MAX_FILE_BUFF Then
m_fb(m_OffSet) = by
m_OffSet = m_OffSet + 1
m_DirtyFlag = True
Else ''''已写满一个缓冲区
WriteBuffToFile
m_fb(0) = by
m_OffSet = 1
m_DirtyFlag = True
End If
End Function
''''看当前指针是否到达文件最尾端
Public Function FEof() As Boolean
If m_LastBuff = False Then
FEof = False
Else
If m_OffSet = m_MaxBytes Then
FEof = True
Else
FEof = False
End If
End If
End Function
''''///////////////////////////////////////////////////////////////////////////////////////
''''预读字节到缓冲区,并返回实际读到的字节,如果返回-1，则表示出错了。
Private Function ReadFileToBuff() As Long
Dim dwReadNum As Long
If ReadFile(m_Handle, m_fb(0), MAX_FILE_BUFF, dwReadNum, 0) = 0 Then
ReadFileToBuff = -1
Else
If dwReadNum <> MAX_FILE_BUFF Then
''''最后一个缓冲区
m_LastBuff = True
m_MaxBytes = dwReadNum
m_OffSet = 0
m_DirtyFlag = False
ReadFileToBuff = dwReadNum
Else
m_LastBuff = False
m_MaxBytes = MAX_FILE_BUFF
m_OffSet = 0
m_DirtyFlag = False
ReadFileToBuff = MAX_FILE_BUFF
End If
End If
End Function
''''写缓冲区到文件，并返回实际写的字节数
Private Function WriteBuffToFile() As Long
Dim dwWriteNum As Long
If m_OffSet = 0 Or m_DirtyFlag = False Then ''''如果写入数为0或者写入标志错则不写入
WriteBuffToFile = 0
Else
If WriteFile(m_Handle, m_fb(0), m_OffSet, dwWriteNum, 0) Then
WriteBuffToFile = dwWriteNum
Else
WriteBuffToFile = -1 ''''出错
End If
End If
m_OffSet = 0
m_DirtyFlag = False
End Function
Private Sub Class_Initialize()
Dim i As Long
m_OffSet = 0
m_Handle = 0
m_DirtyFlag = False
m_FileName = ""
m_LastBuff = False
m_MaxBytes = MAX_FILE_BUFF
End Sub
Private Sub Class_Terminate()
CloseFile
End Sub
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