cbqueue.cpp

linux下的一款播放器

/* ***** BEGIN LICENSE BLOCK *****
 * Source last modified: $Id: cbqueue.cpp,v 1.6.32.3 2004/07/09 01:45:59 hubbe Exp $
 * 
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 * the file under the current version of the RealNetworks Community
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 * ***** END LICENSE BLOCK ***** */

/*******************************************************************
 *
 *	NAME:	CBQueue.h
 *
 *	CLASS:
 *		CByteQueue class declaration.
 *
 *	DESCRIPTION:
 *		Class declaration for a 'Queue of bytes' object.
 *		This object is meant to serve the needs of either clients as
 *		an abstract object, or of subclasses as a base object.
 *
 *		That is a client may use this instances of this class directly,
 *		or they may inherit from the class and provide expanded
 *
 *	NOTES:
 *		The only time a subclass MUST provide a virtual override
 *		is for the GetElementSize() method when the subclass changes
 *		the size of queued elements.  All other virtual methods
 *		provide fully functional default behavior that will ramain
 *		functional even when the ElementSize changes.
 *
 *		The assignment operator is one of the few cases where a
 *		subclass will need to provide new functionality by virtue of
 *		inheriting from the base.  Subclasses should use the base
 *		method for assigning the bits of the base class prior to
 *		performing their own assignment related operations.
 *
 *
 *******************************************************************/


#include "hlxclib/string.h"		//	for memcpy()
#include "hxassert.h"
#include "cbqueue.h"

#if defined( _WINDOWS ) || defined( _WIN32 )
#include <stdlib.h>		//	for __min()
#endif
#if !defined( __min )
#define __min(a,b)  (((a) < (b)) ? (a) : (b))
#endif	//	!defined( __min )

#include "hxheap.h"
#ifdef _DEBUG
#undef HX_THIS_FILE		
static const char HX_THIS_FILE[] = __FILE__;
#endif									 

 /*
 ** CByteQueue::CByteQueue( nSize, nGranularity )
 *
 *  PARAMETERS:
 *		nSize			Number of bytes we want to be able to put in queue
 *		nGranularity	Make our buffer a multiple of this size.
 *							(for subclasses)
 *
 *  DESCRIPTION:
 *		Parameterized constructor.
 *
 *  RETURNS:
 *		void
 */
CByteQueue::CByteQueue( UINT16 nSize, UINT16 nGranularity ) :
	m_pData( 0 ),
	m_pTail( 0 ),
	m_pHead( 0 ),
	m_pMax( 0 ),
	m_nMaxSize(0),
	m_nGranularity( nGranularity )
{
	HX_ASSERT( this );

	//	We add one here because the queue MUST maintain at least one byte
	//	free in the allocated buffer (to distinguish full from empty states).
	m_nSize = CByteQueue::Base_GranulatedSize( nSize, nGranularity ) + 1;
	m_pData = new UCHAR[m_nSize];
	if (!m_pData)
	{
		//	If we used exceptions, now would be a good time
		//	to throw one.
		m_nSize = 0;
		HX_ASSERT( 0 );
		return;
	}
	else
	{
		m_pMax = m_pData + Base_GetBufferSize();
		Base_SetEmpty();
#if defined( _DEBUG )
		HX_ASSERT( IsQueueValid() );
		//	Init our buffer w/ known garbage
		memset( m_pData, 0xfc, Base_GetBufferSize() );
#endif	//	_DEBUG
	}
	return;
}	//	CByteQueue() - Parameterized constructor


/*
 ** CByteQueue::CByteQueue( const CByteQueue &rReferent )
 *
 *  PARAMETERS:
 *		rReferent		A constant reference to the object we want to copy.
 *
 *  DESCRIPTION:
 *		Copy constructor.
 *
 *  RETURNS:
 *		void
 */
CByteQueue::CByteQueue( const CByteQueue &rReferent ) :
	m_pData( 0 ),
	m_pTail( 0 ),
	m_pHead( 0 ),
	m_pMax( 0 ),
	m_nSize( 0 ),
	m_nGranularity( 0 ),
	m_nMaxSize(0)
{
	HX_ASSERT( this );

	//	Are we copying ourselves?  It's a nop if we are.
	if (&rReferent == this)
	{
		return;
	}

	//	Ok, figure out how large a buffer to get and allocate it
	m_pData = new UCHAR[rReferent.Base_GetBufferSize()];
	if (!m_pData)
	{
		//	If we had exceptions, now would be a good time
		//	to throw one.
		m_nSize = 0;
		HX_ASSERT( 0 );
		return;
	}
	else
	{
		m_nSize = rReferent.Base_GetBufferSize();
		m_pMax = m_pData + Base_GetBufferSize();
		m_nGranularity = rReferent.m_nGranularity;

		//	Get a copy of the referent's data into our buffer
		rReferent.Base_PeekBuff( m_pData + 1, Base_GetBufferSize() );
		m_pHead = m_pData;
		m_pTail = m_pData + rReferent.Base_GetUsedByteCount();

#if defined( _DEBUG )
		HX_ASSERT( IsQueueValid() );
		//	Init our buffer w/ known garbage
		memset( m_pData, 0xfc, rReferent.Base_GetBufferSize() );
#endif	//	_DEBUG
	}
	return;
}	//	CByteQueue() - Copy constructor


/*
 ** CByteQueue::~CByteQueue()
 *
 *  PARAMETERS:
 *		void
 *
 *  DESCRIPTION:
 *		Virtual destructor for the base class.
 *
 *  RETURNS:
 *		void
 */
CByteQueue::~CByteQueue()
{
	HX_ASSERT( this );

	if (m_pData)
	{
		HX_ASSERT( IsQueueValid() );    
		delete [] m_pData;
	}
	m_pData = NULL;
	m_pTail = NULL;
	m_pHead = NULL;
	m_pMax = NULL;
	m_nSize = 0;
	m_nGranularity = 0;

#if defined( _DEBUG )
	memset( this, FILLER_BYTE, sizeof( *this ) );
#endif

}	//	~CByteQueue() - Destructor


/*
 ** CByteQueue & CByteQueue::operator=( const CByteQueue &rReferent )
 *
 *  PARAMETERS:
 *		rReferant		Constant reference to an object to assign from (rValue).
 *
 *  DESCRIPTION:
 *		This is our assignment operator.  It assigns from rReferent to
 *		an existing object.
 *
 *  RETURNS:
 *		A reference to ourselves.
 */
CByteQueue & CByteQueue::operator=( const CByteQueue &rReferent )
{
	HX_ASSERT( this );
	HX_ASSERT( rReferent.IsQueueValid() );
	HX_ASSERT( &rReferent );

	//	Do we need to allocate a new buffer?
	if (rReferent.Base_GetBufferSize() != Base_GetBufferSize())
	{
		//	Yes, Allocate the new buffer & copy into it.
		UCHAR *	pByte;

		//	Ok, figure out how large a buffer to get and allocate it
		pByte = new UCHAR[rReferent.Base_GetBufferSize()];
		if (pByte)
		{
			if (m_pData)
			{
				delete [] m_pData;
			}
			m_pData = NULL;
			m_pData = pByte;
		}
		else
		{
			//	Failed buffer allocataion request....
			//	It would be nice if we could fail gracefully or throw
			//	an exception.
			HX_ASSERT( 0 );
			return( *this );
		}
	}

	//	Now need to copy over all of the other elements
	//	Or at least set our elements to the correct data
	m_nSize = rReferent.Base_GetBufferSize();
	m_pMax = m_pData + m_nSize;
	m_nGranularity = rReferent.m_nGranularity;

	//	Get a copy of the referent's data into our buffer
	rReferent.Base_PeekBuff( m_pData + 1, Base_GetBufferSize() );
	m_pHead = m_pData;
	m_pTail = m_pData + rReferent.Base_GetUsedByteCount();

	HX_ASSERT( IsQueueValid() );    
	return( *this );
}	//	operator=()


/*
 ** BOOL CByteQueue::IsQueueValid()
 *
 *  PARAMETERS:
 *		void
 *
 *  DESCRIPTION:
 *		This is meant to validate our queue either for debugging
 *		purposes, or to ensure a queue was correctly created.
 *		(A memory allocation at create time didn't occur).
 *
 *  RETURNS:
 *		void
 */
BOOL CByteQueue::IsQueueValid() const
{
	HX_ASSERT( this );

	//	Ensure we have no NULL pointers & we have a size
	if (!m_pData || !m_pTail || !m_pHead || !m_pMax || !m_nSize ||
	 !m_nGranularity)
	{
		return( FALSE );
	}
	//	Ensure m_pTail is in range