ogg_timestamp.cpp

linux下的一款播放器

/* ***** BEGIN LICENSE BLOCK *****
 * Source last modified: $Id: ogg_timestamp.cpp,v 1.1.4.1 2004/11/24 18:02:52 acolwell Exp $
 * 
 * Portions Copyright (c) 1995-2004 RealNetworks, Inc. All Rights Reserved.
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 * the file under the current version of the RealNetworks Community
 * Source License (the "RCSL") available at
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 * will apply. You may also obtain the license terms directly from
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 * ***** END LICENSE BLOCK ***** */
#include "ogg_timestamp.h"
#include "hxassert.h"

COggTimestamp::COggTimestamp() :
    m_samples(0),
    m_uSampleRate(1),
    m_bLostPrecision(FALSE)
{}

COggTimestamp::COggTimestamp(ogg_int64_t samples, UINT32 uSampleRate) :
    m_samples(samples),
    m_uSampleRate(uSampleRate),
    m_bLostPrecision(FALSE)
{
    HX_ASSERT(m_uSampleRate > 0);
}

void COggTimestamp::SetSampleRate(UINT32 uSampleRate)
{
    HX_ASSERT(m_uSampleRate > 0);
    HX_ASSERT(uSampleRate > 0);

    ogg_int64_t llQ = m_samples / m_uSampleRate;
    ogg_int64_t llR = m_samples - llQ * m_uSampleRate;
    ogg_int64_t llTmp = llR * uSampleRate;
    ogg_int64_t llQ2 = llTmp / m_uSampleRate;
    ogg_int64_t llR2 = llTmp - llQ2 * m_uSampleRate;
   
    m_samples = (llQ * uSampleRate + llQ2);
    m_uSampleRate = uSampleRate;

    if (llR2)
    {
        m_bLostPrecision = TRUE;
    }
}

void COggTimestamp::SetSampleRateToHighest(const COggTimestamp& rhs)
{
    if (m_uSampleRate < rhs.m_uSampleRate)
    {
        SetSampleRate(rhs.m_uSampleRate);
    }
}

COggTimestamp COggTimestamp::operator+ (const COggTimestamp& rhs)
{
    HX_ASSERT(m_uSampleRate == rhs.m_uSampleRate);

    return COggTimestamp(m_samples + rhs.m_samples, m_uSampleRate);
}

COggTimestamp& COggTimestamp::operator+= (const COggTimestamp& rhs)
{
    HX_ASSERT(m_uSampleRate == rhs.m_uSampleRate);

    m_samples += rhs.m_samples;

    return *this;
}

bool COggTimestamp::operator <(const COggTimestamp& rhs)
{
    bool bRet = false;

    ogg_int64_t llLeftSec = m_samples / m_uSampleRate;
    ogg_int64_t llRightSec = rhs.m_samples / rhs.m_uSampleRate;
    
    if (llLeftSec < llRightSec)
    {
        bRet = true;
    }
    else if (llLeftSec == llRightSec)
    {
        ogg_int64_t llLeftFracSec = m_samples % m_uSampleRate;
        ogg_int64_t llRightFracSec = rhs.m_samples % rhs.m_uSampleRate;

        if (m_uSampleRate != rhs.m_uSampleRate)
        {
            llLeftFracSec *= rhs.m_uSampleRate;
            llRightFracSec *= m_uSampleRate;
        }
        
        bRet = (llLeftFracSec < llRightFracSec);
    }

    return bRet;
}