Source code of Windows XP (NT5)
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/*****************************************************************************\
* MODULE: stream.cxx
*
* The module contains the stream interface for file and memory access
*
* Copyright (C) 1997-1998 Microsoft Corporation
*
* History:
* 09/20/00 Weihaic Created
*
\*****************************************************************************/
#include "precomp.h"
#include "priv.h"
CStream::CStream ():
m_dwCurPos (0),
m_bValid(FALSE)
{
}
BOOL
CStream::Reset (
VOID)
{
return SetPtr(0);
}
BOOL
CStream::GetTotalSize (
PDWORD pdwSize) CONST
{
BOOL bRet = FALSE;
if (m_bValid && pdwSize) {
*pdwSize = m_dwTotalSize;
bRet = TRUE;
}
return bRet;
}
CMemStream::CMemStream (
PBYTE pMem,
DWORD dwTotalSize):
m_pMem (pMem)
{
m_dwTotalSize = dwTotalSize;
m_bValid = TRUE;
}
BOOL
CMemStream::SetPtr (
DWORD dwPos)
{
BOOL bRet = FALSE;
if (m_dwCurPos < m_dwTotalSize)
{
m_dwCurPos = dwPos;
bRet = TRUE;
}
return bRet;
}
BOOL
CMemStream::Read (
PBYTE pBuf,
DWORD dwBufSize,
PDWORD pdwSizeRead)
{
DWORD dwSizeLeft = m_dwTotalSize - m_dwCurPos;
*pdwSizeRead = (dwSizeLeft > dwBufSize)?dwBufSize:dwSizeLeft;
CopyMemory (pBuf, m_pMem + m_dwCurPos, *pdwSizeRead);
return TRUE;
}
CFileStream::CFileStream (
HANDLE hFile):
m_hFile (hFile)
{
BOOL bRet = FALSE;
LARGE_INTEGER LargeSize;
if (GetFileSizeEx (m_hFile, &LargeSize) && LargeSize.HighPart == 0) {
m_dwTotalSize = LargeSize.LowPart;
bRet = TRUE;
}
m_bValid = bRet;
}
BOOL
CFileStream::SetPtr (
DWORD dwPos)
{
BOOL bRet = FALSE;
LARGE_INTEGER LargePos;
LargePos.LowPart = dwPos;
LargePos.HighPart = 0;
if (m_bValid) {
if (SetFilePointerEx (m_hFile, LargePos, NULL, FILE_BEGIN)) {
m_dwCurPos = dwPos;
bRet = TRUE;
}
}
return bRet;
}
BOOL
CFileStream::Read (
PBYTE pBuf,
DWORD dwBufSize,
PDWORD pdwSizeRead)
{
BOOL bRet = FALSE;
if (m_bValid) {
if (ReadFile (m_hFile, pBuf, dwBufSize, pdwSizeRead, NULL)) {
m_dwCurPos+= *pdwSizeRead;
bRet = TRUE;
}
}
return bRet;
}