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>('\t', 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>('\t', 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>('\t', 1);

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

}