BOOST 解析，修改，生成xml样例

解析XML

解析iworld XML，拿到entity和VisibleVolume的数据

int ParseiWorlds::readXML(const bpath &dir)
{
	ptree pt;
	try
	{
		read_xml(dir.string(), pt);
	}
	catch (const std::exception& e)
	{
		cout << "read error" << e.what() << endl;
		return -1;
	}

	ptree ptchild = pt.get_child("World.Levels.Level.Root.Entity.RootArea.Root.Entity.Entities");

	for (auto& data : ptchild)
	{
		entity Object;

		ptree ptchildEntity = data.second.get_child("Root.Entity");

		cout << "Name: " << ptchildEntity.get<string>("Name") << endl;
		cout << "Transform: " << ptchildEntity.get<string>("Transform") << endl;
		Object.name = ptchildEntity.get<string>("Name");
		transformMatrix(ptchildEntity.get<string>("Transform"), Object.transform);

		//cube等resource记录在PPrimitives下
		auto PrimitivesCount = ptchildEntity.get<int>("Primitives.<xmlattr>.count");
		if (PrimitivesCount == 1)
		{
			ptchildEntity = ptchildEntity.get_child("Primitives.Element.Root.Entity");

			cout << "Resource: " << ptchildEntity.get<string>("Resource") << endl;
			Object.resource = ptchildEntity.get<string>("Resource");
		}

		//visbilityVolume
		auto VisibilityCube = ptchildEntity.get_child_optional("VisibilityCube.Root.Entity.Resource");
		if (VisibilityCube)
		{
			cout << "Resource: " << ptchildEntity.get<string>("VisibilityCube.Root.Entity.Resource") << endl;
			Object.resource = ptchildEntity.get<string>("VisibilityCube.Root.Entity.Resource");
			Object.isVisibilityVolume = true;
		}

		m_objectMap[Object.name] = Object;
		cout << endl;
	}
	cout << "Object cnt:" << m_objectMap.size() << endl;
	return 1;
}

生成XML

写入XML时候,注意使用setting参数，保证文件内容样式有缩进有对齐

    boost::property_tree::xml_writer_settings<string> settings = boost::property_tree::xml_writer_make_settings<string>('	', 1);

	//把property_tree 转为XML文件
	write_xml(path, pt, std::locale(), settings);

void VisibilityVolume::WriteResourceXML(const string & path)
{
	ptree pt;   
	ptree Resource, Version, SVisibilityCubeData, tNull;

	Resource.put<int>("Version", 1);
	pt.add_child("Resource", Resource);

	ptree Entity, x_WorlBB, x_TileSize, x_SizeX, x_SizeY, x_SizeZ, x_MaxOccluID, x_EffectBitCount, x_EffectBytesPerTile, x_SampleCount;
	
	string world_Str="";
	world_Str = "(" + std::to_string(minX) + ',' + std::to_string(minY) + ',' + std::to_string(minZ) + ',' + 
					  std::to_string(maxX) + ',' + std::to_string(maxY) + ',' + std::to_string(maxZ) + ')';

	x_WorlBB.put_value<string>(world_Str);
	x_TileSize.put_value<int>(cellSize);
	x_SizeY.put_value<int>(SizeX);
	x_SizeY.put_value<int>(SizeY);
	x_SizeZ.put_value<int>(SizeZ);

	x_MaxOccluID.put_value<int>(MaxOccluId);
	x_EffectBitCount.put_value<int>(EffectBitCount);
	x_EffectBytesPerTile.put_value<int>(EffectBytesPerTile);
	x_SampleCount.put_value<int>(SampleCount);


	Entity.put("<xmlattr>.type", "SVisibilityCubeData");
	Entity.add_child("WorlBB", x_WorlBB);
	Entity.add_child("TileSize", x_TileSize);
	Entity.add_child("SizeX", x_SizeY);
	Entity.add_child("SizeY", x_SizeY);
	Entity.add_child("SizeZ", x_SizeZ);
	Entity.add_child("MaxOccluId", x_MaxOccluID);
	Entity.add_child("EffectBitCount", x_EffectBitCount);
	Entity.add_child("EffectBytesPerTile", x_EffectBytesPerTile);
	Entity.add_child("SampleCount", x_SampleCount);

	SVisibilityCubeData.add_child("Root.Sub", tNull);
	SVisibilityCubeData.add_child("Root.Entity", Entity);

	pt.add_child("Resource.SVisibilityCubeData", SVisibilityCubeData);
	//设置写入xml文件的格式，
	boost::property_tree::xml_writer_settings<string> settings = boost::property_tree::xml_writer_make_settings<string>('	', 1);

	//把property_tree 转为XML文件
	write_xml(path, pt, std::locale(), settings);
}

<?xml version="1.0" encoding="utf-8"?>
<Resource>
    <Version>1</Version>
    <SVisibilityCubeData>
        <Root>
            <Sub/>
            <Entity type="SVisibilityCubeData">
                <WorlBB>(-50.000000,-45.000000,-50.000000,50.000000,55.000000,50.000000)</WorlBB>
                <TileSize>5</TileSize>
                <SizeX>20</SizeX>
                <SizeY>20</SizeY>
                <SizeZ>20</SizeZ>
                <MaxOccluId>17</MaxOccluId>
                <EffectBitCount>17</EffectBitCount>
                <EffectBytesPerTile>3</EffectBytesPerTile>
                <SampleCount>141</SampleCount>
            </Entity>
        </Root>
    </SVisibilityCubeData>
</Resource>

修改XML

先读取XML，获得ptree，修改ptree中的节点，注意读取的时候,read_xml参数使用trim_whitespace裁剪空格和换行

read_xml(m_iworldDir.string(), pt, boost::property_tree::xml_parser::trim_whitespace);

void ParseiWorlds::WriteOccluID(map<string, entity> &iworldObj)
{
	ptree pt;
	try
	{
		read_xml(m_iworldDir.string(), pt, boost::property_tree::xml_parser::trim_whitespace);
	}
	catch (const std::exception& e)
	{
		cout << "read error" << e.what() << endl;
	}

	ptree &ptchild = pt.get_child("World.Levels.Level.Root.Entity.RootArea.Root.Entity.Entities");

	//遍历所有items
	for (auto& data : ptchild)
	{
		ptree &items = data.second.get_child("Root.Entity");
		string itemName = items.get<string>("Name");
		int occludID = iworldObj[itemName].OccluId;

		//cube resource等信息记录在Primitives下
		auto PrimitivesCount = items.get<int>("Primitives.<xmlattr>.count");
		if (PrimitivesCount == 1)
		{
			ptree &ptchildEntity = items.get_child("Primitives.Element.Root.Entity");

			ptchildEntity.put<int>("OccluId", occludID);
		}
	}

	//设置写入xml文件的格式
	boost::property_tree::xml_writer_settings<string> settings = boost::property_tree::xml_writer_make_settings<string>('	', 1);

	//把property_tree 转为XML文件
	write_xml(m_iworldDir.string(), pt, std::locale(), settings);
	
}