Method Open

cpp/src/arrow/ipc/feather.cc:149–174

class ReaderV1 : public Reader {
 public:
  Status Open(const std::shared_ptr<io::RandomAccessFile>& source) {
    source_ = source;

    ARROW_ASSIGN_OR_RAISE(int64_t size, source->GetSize());
    int magic_size = static_cast<int>(strlen(kFeatherV1MagicBytes));
    int footer_size = magic_size + static_cast<int>(sizeof(uint32_t));

    // Now get the footer and verify
    ARROW_ASSIGN_OR_RAISE(auto buffer, source->ReadAt(size - footer_size, footer_size,
                                                      /*allow_short_read=*/false));

    if (memcmp(buffer->data() + sizeof(uint32_t), kFeatherV1MagicBytes, magic_size)) {
      return Status::Invalid("Feather file footer incomplete");
    }

    uint32_t metadata_length = *reinterpret_cast<const uint32_t*>(buffer->data());
    if (size < magic_size + footer_size + metadata_length) {
      return Status::Invalid("File is smaller than indicated metadata size");
    }
    ARROW_ASSIGN_OR_RAISE(metadata_buffer_,
                          source->ReadAt(size - footer_size - metadata_length,
                                         metadata_length, /*allow_short_read=*/false));

    metadata_ = fbs::GetCTable(metadata_buffer_->data());
    return ReadSchema();
  }

  Status ReadSchema() {
    std::vector<std::shared_ptr<Field>> fields;