www.pudn.com > DCPlusPlus-src.zip > BitInputStream.h

/*  
 * Copyright (C) 2001-2004 Jacek Sieka, j_s at telia com 
 * 
 * This program is free software; you can redistribute it and/or modify 
 * it under the terms of the GNU General Public License as published by 
 * the Free Software Foundation; either version 2 of the License, or 
 * (at your option) any later version. 
 * 
 * This program is distributed in the hope that it will be useful, 
 * but WITHOUT ANY WARRANTY; without even the implied warranty of 
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
 * GNU General Public License for more details. 
 * 
 * You should have received a copy of the GNU General Public License 
 * along with this program; if not, write to the Free Software 
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 
 */ 
 
#if !defined(AFX_BITINPUTSTREAM_H__EAF695A9_6D5C_4791_88A2_3FA0D47697AF__INCLUDED_) 
#define AFX_BITINPUTSTREAM_H__EAF695A9_6D5C_4791_88A2_3FA0D47697AF__INCLUDED_ 
 
#if _MSC_VER > 1000 
#pragma once 
#endif // _MSC_VER > 1000 
 
#include "Exception.h" 
 
STANDARD_EXCEPTION(BitStreamException); 
 
/** 
 * A clumsy bit streamer, assumes that there's enough data to complete the operations. 
 * No, doesn't operate on streams...=) 
 */ 
class BitInputStream   
{ 
public: 
	BitInputStream(const u_int8_t* aStream, size_t aStart, size_t aEnd) : endPos(aEnd*8), bitPos(aStart*8), is(aStream) { }; 
	~BitInputStream() { }; 
	 
	bool get() throw(BitStreamException) { 
		if(bitPos > endPos) { 
			throw BitStreamException(STRING(SEEK_BEYOND_END)); 
		} 
		bool ret = (((u_int8_t)is[bitPos>>3]) >> (bitPos&0x07)) & 0x01; 
		bitPos++; 
		return ret; 
	} 
	 
	void skipToByte() { 
		if(bitPos%8 != 0) 
			bitPos = (bitPos & (~7)) + 8; 
	} 
	 
	void skip(int n) { 
		bitPos += n * 8; 
		return ; 
	} 
private: 
	size_t bitPos; 
	size_t endPos; 
	const u_int8_t* is; 
}; 
 
#endif // !defined(AFX_BITINPUTSTREAM_H__EAF695A9_6D5C_4791_88A2_3FA0D47697AF__INCLUDED_) 
 
/** 
 * @file 
 * $Id: BitInputStream.h,v 1.12 2004/09/26 18:54:08 arnetheduck Exp $ 
 */