inbuffer.cpp

nsis是一个流传比较广的程序安装和解安装封装软件

/*
 * InBuffer.cpp
 * 
 * This file is a part of LZMA compression module for NSIS.
 * 
 * Original LZMA SDK Copyright (C) 1999-2006 Igor Pavlov
 * Modifications Copyright (C) 2003-2006 Amir Szekely <[e-mail]>
 * 
 * Licensed under the Common Public License version 1.0 (the "License");
 * you may not use this file except in compliance with the License.
 * 
 * Licence details can be found in the file COPYING.
 * 
 * This software is provided 'as-is', without any express or implied
 * warranty.
 */

#include "StdAfx.h"

#include "InBuffer.h"

#include "../../Common/Alloc.h"

CInBuffer::CInBuffer(): 
  _buffer(0), 
  _bufferLimit(0), 
  _bufferBase(0), 
  _stream(0),
  _bufferSize(0)
{}

bool CInBuffer::Create(UInt32 bufferSize)
{
  const UInt32 kMinBlockSize = 1;
  if (bufferSize < kMinBlockSize)
    bufferSize = kMinBlockSize;
  if (_bufferBase != 0 && _bufferSize == bufferSize)
    return true;
  Free();
  _bufferSize = bufferSize;
  _bufferBase = (Byte *)::MidAlloc(bufferSize);
  return (_bufferBase != 0);
}

void CInBuffer::Free()
{
  ::MidFree(_bufferBase);
  _bufferBase = 0;
}

void CInBuffer::SetStream(ISequentialInStream *stream)
{
  _stream = stream;
}

void CInBuffer::Init()
{
  _processedSize = 0;
  _buffer = _bufferBase;
  _bufferLimit = _buffer;
  _wasFinished = false;
  #ifdef _NO_EXCEPTIONS
  ErrorCode = S_OK;
  #endif
}

bool CInBuffer::ReadBlock()
{
  #ifdef _NO_EXCEPTIONS
  if (ErrorCode != S_OK)
    return false;
  #endif
  if (_wasFinished)
    return false;
  _processedSize += (_buffer - _bufferBase);
  UInt32 numProcessedBytes;
  HRESULT result = _stream->Read(_bufferBase, _bufferSize, &numProcessedBytes);
  #ifdef _NO_EXCEPTIONS
  ErrorCode = result;
  #else
  if (result != S_OK)
    throw CInBufferException(result);
  #endif
  _buffer = _bufferBase;
  _bufferLimit = _buffer + numProcessedBytes;
  _wasFinished = (numProcessedBytes == 0);
  return (!_wasFinished);
}

Byte CInBuffer::ReadBlock2()
{
  if(!ReadBlock())
    return 0xFF;
  return *_buffer++;
}