www.pudn.com > eMule0.42e-Sources.zip > xmemfile.cpp

#include "xmemfile.h" 
 
////////////////////////////////////////////////////////// 
size_t CxMemFile::Read(void *buffer, size_t size, size_t count) 
{ 
	if (m_pBuffer==NULL) return 0; 
	if (buffer==NULL) return 0; 
	if (m_Position > (long)m_Size) return 0; 
 
	long nCount = count*size; 
	if (nCount == 0) return 0; 
 
	long nRead; 
	if (m_Position + nCount > (long)m_Size) 
		nRead = (m_Size - m_Position); 
	else 
		nRead = nCount; 
 
	memcpy(buffer, m_pBuffer + m_Position, nRead); 
	m_Position += nRead; 
 
	return (size_t)(nRead/size); 
} 
////////////////////////////////////////////////////////// 
size_t CxMemFile::Write(const void *buffer, size_t size, size_t count) 
{ 
	if (m_pBuffer==NULL) return 0; 
	if (buffer==NULL) return 0; 
 
	long nCount = count*size; 
	if (nCount == 0) return 0; 
 
	if (m_Position + nCount > m_Edge) Alloc(m_Position + nCount); 
 
	memcpy(m_pBuffer + m_Position, buffer, nCount); 
 
	m_Position += nCount; 
 
	if (m_Position > (long)m_Size) m_Size = m_Position; 
	 
	return count; 
} 
////////////////////////////////////////////////////////// 
bool CxMemFile::Seek(long offset, int origin) 
{ 
	if (m_pBuffer==NULL) return false; 
	long lNewPos = m_Position; 
 
	if (origin == SEEK_SET)		 lNewPos = offset; 
	else if (origin == SEEK_CUR) lNewPos += offset; 
	else if (origin == SEEK_END) lNewPos = m_Size + offset; 
	else return false; 
 
	if (lNewPos < 0) return false; 
 
	m_Position = lNewPos; 
	return true; 
} 
////////////////////////////////////////////////////////// 
long CxMemFile::Tell() 
{ 
	if (m_pBuffer==NULL) return -1; 
	return m_Position; 
} 
////////////////////////////////////////////////////////// 
long CxMemFile::Size() 
{ 
	if (m_pBuffer==NULL) return -1; 
	return m_Size; 
} 
////////////////////////////////////////////////////////// 
bool CxMemFile::Flush() 
{ 
	if (m_pBuffer==NULL) return false; 
	return true; 
} 
////////////////////////////////////////////////////////// 
bool CxMemFile::Eof() 
{ 
	if (m_pBuffer==NULL) return true; 
	return (m_Position >= (long)m_Size); 
} 
////////////////////////////////////////////////////////// 
long CxMemFile::Error() 
{ 
	if (m_pBuffer==NULL) return -1; 
	return (m_Position > (long)m_Size); 
} 
////////////////////////////////////////////////////////// 
bool CxMemFile::PutC(unsigned char c) 
{ 
	if (m_pBuffer==NULL) return false; 
	if (m_Position + 1 > m_Edge) Alloc(m_Position + 1); 
 
	memcpy(m_pBuffer + m_Position, &c, 1); 
 
	m_Position += 1; 
 
	if (m_Position > (long)m_Size) m_Size = m_Position; 
	 
	return true; 
} 
////////////////////////////////////////////////////////// 
long CxMemFile::GetC() 
{ 
	if (Eof()) return EOF; 
	return *(BYTE*)((BYTE*)m_pBuffer + m_Position++); 
} 
////////////////////////////////////////////////////////// 
void CxMemFile::Alloc(DWORD dwNewLen) 
{ 
	if (dwNewLen > (DWORD)m_Edge) 
	{ 
		// determine new buffer size 
		DWORD dwNewBufferSize = (DWORD)m_Edge; 
		while (dwNewBufferSize < dwNewLen) dwNewBufferSize += 4096; 
 
		// allocate new buffer 
		if (m_pBuffer == NULL) m_pBuffer = (BYTE*)malloc(dwNewBufferSize); 
		else	m_pBuffer = (BYTE*)realloc(m_pBuffer, dwNewBufferSize); 
		// I own this buffer now (caller knows nothing about it) 
		m_bFreeOnClose = true; 
 
		m_Edge = dwNewBufferSize; 
	} 
	return; 
} 
////////////////////////////////////////////////////////// 
void CxMemFile::Free() 
{ 
	Close(); 
} 
//////////////////////////////////////////////////////////