Function xml_parse_status load_stream_data_noseek

Tools/EditorFramework/pugixml.cpp:3926–3982

template<typename T>
PUGI__FN xml_parse_status load_stream_data_noseek(std::basic_istream<T>& stream, void** out_buffer, size_t* out_size)
{
	buffer_holder chunks(0, xml_stream_chunk<T>::destroy);

	// read file to a chunk list
	size_t total = 0;
	xml_stream_chunk<T>* last = nullptr;

	while (!stream.eof())
	{
		// allocate new chunk
		xml_stream_chunk<T>* chunk = xml_stream_chunk<T>::create();
		if (!chunk)
			return status_out_of_memory;

		// append chunk to list
		if (last)
			last = last->next = chunk;
		else
			chunks.data = last = chunk;

		// read data to chunk
		stream.read(chunk->data, static_cast<std::streamsize>(sizeof(chunk->data) / sizeof(T)));
		chunk->size = static_cast<size_t>(stream.gcount()) * sizeof(T);

		// read may set failbit | eofbit in case gcount() is less than read length, so check for other I/O errors
		if (stream.bad() || (!stream.eof() && stream.fail()))
			return status_io_error;

		// guard against huge files (chunk size is small enough to make this overflow check work)
		if (total + chunk->size < total)
			return status_out_of_memory;
		total += chunk->size;
	}

	// copy chunk list to a contiguous buffer
	char* buffer = static_cast<char*>(xml_memory::allocate(total));
	if (!buffer)
		return status_out_of_memory;

	char* write = buffer;

	for (xml_stream_chunk<T>* chunk = static_cast<xml_stream_chunk<T>*>(chunks.data); chunk; chunk = chunk->next)
	{
		assert(write + chunk->size <= buffer + total);
		memcpy(write, chunk->data, chunk->size);
		write += chunk->size;
	}

	assert(write == buffer + total);

	// return buffer
	*out_buffer = buffer;
	*out_size = total;

	return status_ok;
}