diff --git a/cppwinrt/text_writer.h b/cppwinrt/text_writer.h index a274d11ce..c6fc380b3 100644 --- a/cppwinrt/text_writer.h +++ b/cppwinrt/text_writer.h @@ -13,8 +13,26 @@ namespace cppwinrt { inline std::string file_to_string(std::string const& filename) { - std::ifstream file(filename, std::ios::binary); - return static_cast(std::stringstream() << file.rdbuf()).str(); + std::ifstream file(filename, std::ios::binary | std::ios::ate); + if (!file) { return{}; } + + const auto stream_size = file.tellg(); + if (stream_size == std::ifstream::pos_type(-1)) + { + return {}; + } + + file.seekg(0); + + auto size = static_cast(stream_size); + std::string result(size, '\0'); + file.read(result.data(), size); + if (!file) + { + result.resize(static_cast(file.gcount())); + } + + return result; } template @@ -218,18 +236,15 @@ namespace cppwinrt bool file_equal(std::string const& filename) const { - if (!std::filesystem::exists(filename)) + // Non-throwing file_size returns uintmax_t(-1) on errors, which shouldn't ever be the size of m_first or m_second + std::error_code ec; + if (std::filesystem::file_size(filename, ec) != m_first.size() + m_second.size()) { return false; } auto file = file_to_string(filename); - if (file.size() != m_first.size() + m_second.size()) - { - return false; - } - if (!std::equal(m_first.begin(), m_first.end(), file.begin(), file.begin() + m_first.size())) { return false;