Method ReadFileHeader

code/AssetLib/STEPParser/STEPFileReader.cpp:84–137

------------------------------------------------------------------------------------------------

static constexpr char FILE_SCHEMA_Token[] = "FILE_SCHEMA";
// ------------------------------------------------------------------------------------------------
STEP::DB* STEP::ReadFileHeader(std::shared_ptr<IOStream> stream) {
    std::shared_ptr<StreamReaderLE> reader = std::shared_ptr<StreamReaderLE>(new StreamReaderLE(std::move(stream)));
    std::unique_ptr<STEP::DB> db = std::unique_ptr<STEP::DB>(new STEP::DB(reader));

    LineSplitter &splitter = db->GetSplitter();
    if (!splitter || *splitter != ISO_Token ) {
        throw STEP::SyntaxError("expected magic token: " + std::string( ISO_Token ), 1);
    }

    HeaderInfo& head = db->GetHeader();
    for(++splitter; splitter; ++splitter) {
        const std::string& s = *splitter;
        if (s == "DATA;") {
            // here we go, header done, start of data section
            ++splitter;
            break;
        }

        // want one-based line numbers for human readers, so +1
        const uint64_t line = splitter.get_index()+1;

        if (s.substr(0,11) == FILE_SCHEMA_Token) {
            const char* sz = s.c_str()+11;
            const char *end = s.c_str() + s.size();
            SkipSpaces(sz,&sz, end);
            std::shared_ptr< const EXPRESS::DataType > schema = EXPRESS::DataType::Parse(sz, end);

            // the file schema should be a regular list entity, although it usually contains exactly one entry
            // since the list itself is contained in a regular parameter list, we actually have
            // two nested lists.
            const EXPRESS::LIST* list = dynamic_cast<const EXPRESS::LIST*>(schema.get());
            if (list && list->GetSize()) {
                list = dynamic_cast<const EXPRESS::LIST*>( (*list)[0].get() );
                if (!list) {
                    throw STEP::SyntaxError("expected FILE_SCHEMA to be a list",line);
                }

                // XXX need support for multiple schemas?
                if (list->GetSize() > 1)    {
                    ASSIMP_LOG_WARN(AddLineNumber("multiple schemas currently not supported",line));
                }
                const EXPRESS::STRING *string = dynamic_cast<const EXPRESS::STRING *>((*list)[0].get());
                if (!list->GetSize() || nullptr == string ) {
                    throw STEP::SyntaxError("expected FILE_SCHEMA to contain a single string literal",line);
                }
                head.fileSchema =  *string;
            }
        }

        // XXX handle more header fields
    }

    return db.release();
}


namespace {