C++ LineReader::ValueAsSignedInt方法代码示例

// ------------------------------------------------------------------------------------------------
void DXFImporter::ParsePolyLine(DXF::LineReader& reader, DXF::FileData& output)
{
    output.blocks.back().lines.push_back( std::shared_ptr<DXF::PolyLine>( new DXF::PolyLine() ) );
    DXF::PolyLine& line = *output.blocks.back().lines.back();

    unsigned int iguess = 0, vguess = 0;
    while( !reader.End() && !reader.Is(0,"ENDSEC")) {

        if (reader.Is(0,"VERTEX")) {
            ParsePolyLineVertex(++reader,line);
            if (reader.Is(0,"SEQEND")) {
                break;
            }
            continue;
        }

        switch(reader.GroupCode())
        {
        // flags --- important that we know whether it is a
        // polyface mesh or 'just' a line.
        case 70:
            if (!line.flags)    {
                line.flags = reader.ValueAsSignedInt();
            }
            break;

        // optional number of vertices
        case 71:
            vguess = reader.ValueAsSignedInt();
            line.positions.reserve(vguess);
            break;

        // optional number of faces
        case 72:
            iguess = reader.ValueAsSignedInt();
            line.indices.reserve(iguess);
            break;

        // 8 specifies the layer on which this line is placed on
        case 8:
            line.layer = reader.Value();
            break;
        }

        reader++;
    }

    //if (!(line.flags & DXF_POLYLINE_FLAG_POLYFACEMESH))   {
    //  DefaultLogger::get()->warn((Formatter::format("DXF: polyline not currently supported: "),line.flags));
    //  output.blocks.back().lines.pop_back();
    //  return;
    //}

    if (vguess && line.positions.size() != vguess) {
        DefaultLogger::get()->warn((Formatter::format("DXF: unexpected vertex count in polymesh: "),
            line.positions.size(),", expected ", vguess
        ));
    }

    if (line.flags & DXF_POLYLINE_FLAG_POLYFACEMESH ) {
        if (line.positions.size() < 3 || line.indices.size() < 3)   {
                DefaultLogger::get()->warn("DXF: not enough vertices for polymesh; ignoring");
                output.blocks.back().lines.pop_back();
                return;
        }

        // if these numbers are wrong, parsing might have gone wild.
        // however, the docs state that applications are not required
        // to set the 71 and 72 fields, respectively, to valid values.
        // So just fire a warning.
        if (iguess && line.counts.size() != iguess) {
            DefaultLogger::get()->warn((Formatter::format("DXF: unexpected face count in polymesh: "),
                line.counts.size(),", expected ", iguess
            ));
        }
    }
    else if (!line.indices.size() && !line.counts.size()) {
        // a polyline - so there are no indices yet.
        size_t guess = line.positions.size() + (line.flags & DXF_POLYLINE_FLAG_CLOSED ? 1 : 0);
        line.indices.reserve(guess);

        line.counts.reserve(guess/2);
        for (unsigned int i = 0; i < line.positions.size()/2; ++i) {
            line.indices.push_back(i*2);
            line.indices.push_back(i*2+1);
            line.counts.push_back(2);
        }

        // closed polyline?
        if (line.flags & DXF_POLYLINE_FLAG_CLOSED) {
            line.indices.push_back(static_cast<unsigned int>(line.positions.size()-1));
            line.indices.push_back(0);
            line.counts.push_back(2);
        }
    }
}