164 lines
2.5 KiB
C++
164 lines
2.5 KiB
C++
#include "StdAfx.h"
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#include "Buffer.h"
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#include <math.h>
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#define U_PAGE_ALIGNMENT 3
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#define F_PAGE_ALIGNMENT 3.0
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CBuffer::CBuffer()
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{
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m_ulMaxLength = 0;
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m_Ptr = m_Base = NULL;
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}
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CBuffer::~CBuffer(void)
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{
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if (m_Base)
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{
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VirtualFree(m_Base, 0, MEM_RELEASE);
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m_Base = NULL;
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}
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m_Base = m_Ptr = NULL;
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m_ulMaxLength = 0;
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}
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ULONG CBuffer::ReadBuffer(PBYTE Buffer, ULONG ulLength)
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{
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if (ulLength > GetBufferMaxLength())
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{
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return 0;
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}
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if (ulLength > GetBufferLength())
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{
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ulLength = GetBufferLength();
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}
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if (ulLength)
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{
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CopyMemory(Buffer,m_Base,ulLength);
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MoveMemory(m_Base,m_Base+ulLength,GetBufferMaxLength() - ulLength);
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m_Ptr -= ulLength;
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}
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DeAllocateBuffer(GetBufferLength());
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return ulLength;
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}
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ULONG CBuffer::DeAllocateBuffer(ULONG ulLength)
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{
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if (ulLength < GetBufferLength())
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return 0;
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ULONG ulNewMaxLength = (ULONG)ceil(ulLength / F_PAGE_ALIGNMENT) * U_PAGE_ALIGNMENT;
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if (GetBufferMaxLength() <= ulNewMaxLength)
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{
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return 0;
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}
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PBYTE NewBase = (PBYTE) VirtualAlloc(NULL,ulNewMaxLength,MEM_COMMIT,PAGE_READWRITE);
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ULONG ulv1 = GetBufferLength(); //算原先内存的有效长度
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CopyMemory(NewBase,m_Base,ulv1);
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VirtualFree(m_Base,0,MEM_RELEASE);
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m_Base = NewBase;
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m_Ptr = m_Base + ulv1;
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m_ulMaxLength = ulNewMaxLength;
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return m_ulMaxLength;
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}
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BOOL CBuffer::WriteBuffer(PBYTE Buffer, ULONG ulLength)
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{
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if (ReAllocateBuffer(ulLength + GetBufferLength()) == -1)//10 +1 1024
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{
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return false;
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}
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CopyMemory(m_Ptr,Buffer,ulLength);//Hello 5
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m_Ptr+=ulLength;
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return TRUE;
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}
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ULONG CBuffer::ReAllocateBuffer(ULONG ulLength)
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{
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if (ulLength < GetBufferMaxLength())
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return 0;
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ULONG ulNewMaxLength = (ULONG)ceil(ulLength / F_PAGE_ALIGNMENT) * U_PAGE_ALIGNMENT;
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PBYTE NewBase = (PBYTE) VirtualAlloc(NULL,ulNewMaxLength,MEM_COMMIT,PAGE_READWRITE);
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if (NewBase == NULL)
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{
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return -1;
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}
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ULONG ulv1 = GetBufferLength(); //原先的有效数据长度
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CopyMemory(NewBase,m_Base,ulv1);
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if (m_Base)
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{
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VirtualFree(m_Base,0,MEM_RELEASE);
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}
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m_Base = NewBase;
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m_Ptr = m_Base + ulv1; //1024
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m_ulMaxLength = ulNewMaxLength; //2048
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return m_ulMaxLength;
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}
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VOID CBuffer::ClearBuffer()
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{
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m_Ptr = m_Base;
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DeAllocateBuffer(1024);
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}
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ULONG CBuffer::GetBufferLength() const //获得有效数据长度
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{
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if (m_Base == NULL)
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return 0;
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return (ULONG)m_Ptr - (ULONG)m_Base;
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}
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ULONG CBuffer::GetBufferMaxLength() const
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{
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return m_ulMaxLength;
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}
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PBYTE CBuffer::GetBuffer(ULONG ulPos) const
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{
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if (m_Base==NULL)
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{
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return NULL;
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}
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if (ulPos>=GetBufferLength())
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{
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return NULL;
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}
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return m_Base+ulPos;
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}
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