Ap4Descriptor.h

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/*****************************************************************
|
|    AP4 - Descriptors 
|
|    Copyright 2002-2006 Gilles Boccon-Gibod & Julien Boeuf
|
|
|    This file is part of Bento4/AP4 (MP4 Atom Processing Library).
|
|    Unless you have obtained Bento4 under a difference license,
|    this version of Bento4 is Bento4|GPL.
|    Bento4|GPL 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, or (at your option)
|    any later version.
|
|    Bento4|GPL 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 Bento4|GPL; see the file COPYING.  If not, write to the
|    Free Software Foundation, 59 Temple Place - Suite 330, Boston, MA
|    02111-1307, USA.
|
 ****************************************************************/

#ifndef _AP4_DESCRIPTOR_H_
#define _AP4_DESCRIPTOR_H_

/*----------------------------------------------------------------------
|   includes
+---------------------------------------------------------------------*/
#include "Ap4Types.h"
#include "Ap4List.h"

/*----------------------------------------------------------------------
|   class references
+---------------------------------------------------------------------*/
class AP4_ByteStream;
class AP4_AtomInspector;

/*----------------------------------------------------------------------
|   AP4_Descriptor
+---------------------------------------------------------------------*/
class AP4_Descriptor 
{
 public:
    // types
    typedef unsigned char Tag;

    // class methods
    static AP4_Size MinHeaderSize(AP4_Size payload_size);

    // methods
    AP4_Descriptor(Tag tag, AP4_Size header_size, AP4_Size payload_size);
    virtual ~AP4_Descriptor() {}
    Tag                GetTag()  { return m_Tag; }
    AP4_Size           GetSize() { return m_PayloadSize+m_HeaderSize; }
    AP4_Size           GetHeaderSize() { return m_HeaderSize; }
    virtual AP4_Result Write(AP4_ByteStream& stream);
    virtual AP4_Result WriteFields(AP4_ByteStream& stream) = 0;
    virtual AP4_Result Inspect(AP4_AtomInspector& inspector);

 protected:
    // members
    Tag      m_Tag;
    AP4_Size m_HeaderSize;
    AP4_Size m_PayloadSize;
};

/*----------------------------------------------------------------------
|   AP4_DescriptorFinder
+---------------------------------------------------------------------*/
class AP4_DescriptorFinder : public AP4_List<AP4_Descriptor>::Item::Finder
{
 public:
    AP4_DescriptorFinder(AP4_Descriptor::Tag tag) : m_Tag(tag) {}
    AP4_Result Test(AP4_Descriptor* descriptor) const {
        return descriptor->GetTag() == m_Tag ? AP4_SUCCESS : AP4_FAILURE;
    }
 private:
    AP4_Descriptor::Tag m_Tag;
};

/*----------------------------------------------------------------------
|   AP4_DescriptorListWriter
+---------------------------------------------------------------------*/
class AP4_DescriptorListWriter : public AP4_List<AP4_Descriptor>::Item::Operator
{
public:
    AP4_DescriptorListWriter(AP4_ByteStream& stream) :
      m_Stream(stream) {}
    AP4_Result Action(AP4_Descriptor* descriptor) const {
        return descriptor->Write(m_Stream);
    }

private:
    AP4_ByteStream& m_Stream;
};

/*----------------------------------------------------------------------
|   AP4_DescriptorListInspector
+---------------------------------------------------------------------*/
class AP4_DescriptorListInspector : public AP4_List<AP4_Descriptor>::Item::Operator
{
 public:
    AP4_DescriptorListInspector(AP4_AtomInspector& inspector) :
        m_Inspector(inspector) {}
    AP4_Result Action(AP4_Descriptor* descriptor) const {
        descriptor->Inspect(m_Inspector);
        return AP4_SUCCESS;
    }

 private:
    AP4_AtomInspector& m_Inspector;
};

#endif // _AP4_DESCRIPTOR_H_

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