atom_root.cpp

6410BSP1

/*
 * The contents of this file are subject to the Mozilla Public
 * License Version 1.1 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.mozilla.org/MPL/
 * 
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 * 
 * The Original Code is MPEG4IP.
 * 
 * The Initial Developer of the Original Code is Cisco Systems Inc.
 * Portions created by Cisco Systems Inc. are
 * Copyright (C) Cisco Systems Inc. 2001.  All Rights Reserved.
 * 
 * Contributor(s): 
 *        Dave Mackie        [e-mail]
 */

#include "mp4common.h"

MP4RootAtom::MP4RootAtom() 
    : MP4Atom(NULL)
{
    ExpectChildAtom("moov", Required, OnlyOne);
    ExpectChildAtom("ftyp", Optional, OnlyOne);
    ExpectChildAtom("mdat", Optional, Many);
    ExpectChildAtom("free", Optional, Many);
    ExpectChildAtom("skip", Optional, Many);
    ExpectChildAtom("udta", Optional, Many);
    ExpectChildAtom("moof", Optional, Many);
}

void MP4RootAtom::BeginWrite(bool use64) 
{
    // only call under MP4Create() control
    WriteAtomType("ftyp", OnlyOne);

    m_pChildAtoms[GetLastMdatIndex()]->BeginWrite(m_pFile->Use64Bits("mdat"));
}

void MP4RootAtom::Write()
{
    // no-op
}

void MP4RootAtom::FinishWrite(bool use64)
{
    // finish writing last mdat atom
    u_int32_t mdatIndex = GetLastMdatIndex();
    m_pChildAtoms[mdatIndex]->FinishWrite(m_pFile->Use64Bits("mdat"));

    // write all atoms after last mdat
    u_int32_t size = m_pChildAtoms.Size();
    for (u_int32_t i = mdatIndex + 1; i < size; i++) {
        m_pChildAtoms[i]->Write();
    }
}

void MP4RootAtom::BeginOptimalWrite() 
{
    WriteAtomType("ftyp", OnlyOne);
    WriteAtomType("moov", OnlyOne);
    WriteAtomType("udta", Many);

    m_pChildAtoms[GetLastMdatIndex()]->BeginWrite(m_pFile->Use64Bits("mdat"));
}

void MP4RootAtom::FinishOptimalWrite() 
{
    // finish writing mdat
    m_pChildAtoms[GetLastMdatIndex()]->FinishWrite(m_pFile->Use64Bits("mdat"));

    // find moov atom
    u_int32_t size = m_pChildAtoms.Size();
    MP4Atom* pMoovAtom = NULL;

    u_int32_t i;
    for (i = 0; i < size; i++) {
        if (!strcmp("moov", m_pChildAtoms[i]->GetType())) {
            pMoovAtom = m_pChildAtoms[i];
            break;
        }
    }
    ASSERT(i < size);

    // rewrite moov so that updated chunkOffsets are written to disk
    m_pFile->SetPosition(pMoovAtom->GetStart());
    u_int64_t oldSize = pMoovAtom->GetSize();

    pMoovAtom->Write();

    // sanity check
    u_int64_t newSize = pMoovAtom->GetSize();
    ASSERT(oldSize == newSize);
}

u_int32_t MP4RootAtom::GetLastMdatIndex()
{
    for (int32_t i = m_pChildAtoms.Size() - 1; i >= 0; i--) {
        if (!strcmp("mdat", m_pChildAtoms[i]->GetType())) {
            return i;
        }
    }
    ASSERT(false);
    return (u_int32_t)-1;
}

void MP4RootAtom::WriteAtomType(const char* type, bool onlyOne)
{
    u_int32_t size = m_pChildAtoms.Size();

    for (u_int32_t i = 0; i < size; i++) {
        if (!strcmp(type, m_pChildAtoms[i]->GetType())) {
            m_pChildAtoms[i]->Write();
            if (onlyOne) {
                break;
            }
        }
    }
}