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|
/*****************************************************************
|
| AP4 - schm Atoms
|
| Copyright 2002-2008 Axiomatic Systems, LLC
|
|
| 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.
|
****************************************************************/
/*----------------------------------------------------------------------
| includes
+---------------------------------------------------------------------*/
#include "Ap4SchmAtom.h"
#include "Ap4AtomFactory.h"
#include "Ap4Utils.h"
/*----------------------------------------------------------------------
| dynamic cast support
+---------------------------------------------------------------------*/
AP4_DEFINE_DYNAMIC_CAST_ANCHOR(AP4_SchmAtom)
/*----------------------------------------------------------------------
| AP4_SchmAtom::Create
+---------------------------------------------------------------------*/
AP4_SchmAtom*
AP4_SchmAtom::Create(AP4_Size size,
AP4_Array<AP4_Atom::Type>* context,
AP4_ByteStream& stream)
{
AP4_UI08 version;
AP4_UI32 flags;
if (AP4_FAILED(AP4_Atom::ReadFullHeader(stream, version, flags))) return NULL;
if (version != 0) return NULL;
if (size < AP4_FULL_ATOM_HEADER_SIZE+6) return NULL;
// check the context to see if this is a short form atom or not
bool short_form = false;
if (size < AP4_FULL_ATOM_HEADER_SIZE+8) short_form = true;
if (context) {
AP4_Size context_depth = context->ItemCount();
if (context_depth >= 2 &&
(*context)[context_depth-2] == AP4_ATOM_TYPE('m','r','l','n')) {
short_form = true;
}
}
return new AP4_SchmAtom(size, version, flags, short_form, stream);
}
/*----------------------------------------------------------------------
| AP4_SchmAtom::AP4_SchmAtom
+---------------------------------------------------------------------*/
AP4_SchmAtom::AP4_SchmAtom(AP4_UI32 scheme_type,
AP4_UI32 scheme_version,
const char* scheme_uri,
bool short_form) :
AP4_Atom(AP4_ATOM_TYPE_SCHM, AP4_FULL_ATOM_HEADER_SIZE+4+(short_form?2:4), 0, 0),
m_AtomHasShortForm(short_form),
m_SchemeType(scheme_type),
m_SchemeVersion(scheme_version)
{
if (scheme_uri) {
m_SchemeUri = scheme_uri;
m_Flags = 1;
m_Size32 += m_SchemeUri.GetLength()+1;
}
}
/*----------------------------------------------------------------------
| AP4_SchmAtom::AP4_SchmAtom
+---------------------------------------------------------------------*/
AP4_SchmAtom::AP4_SchmAtom(AP4_UI32 size,
AP4_UI08 version,
AP4_UI32 flags,
bool short_form,
AP4_ByteStream& stream) :
AP4_Atom(AP4_ATOM_TYPE_SCHM, size, version, flags),
m_AtomHasShortForm(short_form)
{
stream.ReadUI32(m_SchemeType);
if (short_form) {
AP4_UI16 short_version;
stream.ReadUI16(short_version);
m_SchemeVersion = short_version;
} else {
stream.ReadUI32(m_SchemeVersion);
}
if (m_Flags & 1) {
int str_size = size-(AP4_FULL_ATOM_HEADER_SIZE+8);
if (str_size > 0) {
char* str = new char[str_size];
stream.Read(str, str_size);
str[str_size-1] = '\0'; // force null-termination
m_SchemeUri = str;
delete[] str;
}
}
}
/*----------------------------------------------------------------------
| AP4_SchmAtom::WriteFields
+---------------------------------------------------------------------*/
AP4_Result
AP4_SchmAtom::WriteFields(AP4_ByteStream& stream)
{
AP4_Result result;
// scheme type
result = stream.WriteUI32(m_SchemeType);
if (AP4_FAILED(result)) return result;
// scheme version
if (m_AtomHasShortForm) {
result = stream.WriteUI16((AP4_UI16)m_SchemeVersion);
if (AP4_FAILED(result)) return result;
} else {
result = stream.WriteUI32(m_SchemeVersion);
if (AP4_FAILED(result)) return result;
}
// uri if needed
if (m_Flags & 1) {
result = stream.Write(m_SchemeUri.GetChars(), m_SchemeUri.GetLength()+1);
if (AP4_FAILED(result)) return result;
// pad with zeros if necessary
AP4_Size fields_size = 4+(m_AtomHasShortForm?2:4);
AP4_Size padding = m_Size32-(AP4_FULL_ATOM_HEADER_SIZE+fields_size+m_SchemeUri.GetLength()+1);
while (padding--) stream.WriteUI08(0);
}
return result;
}
/*----------------------------------------------------------------------
| AP4_SchmAtom::InspectFields
+---------------------------------------------------------------------*/
AP4_Result
AP4_SchmAtom::InspectFields(AP4_AtomInspector& inspector)
{
char st[5];
AP4_FormatFourChars(st, m_SchemeType);
inspector.AddField("scheme_type", st);
if (m_AtomHasShortForm) {
inspector.AddField("scheme_version (short)", m_SchemeVersion);
} else {
inspector.AddField("scheme_version", m_SchemeVersion);
}
if (m_Flags & 1) {
inspector.AddField("scheme_uri", m_SchemeUri.GetChars());
}
return AP4_SUCCESS;
}
|
