[#1] Add CppRuntimeException from Zserio C++ runtime

* without support for bitmasks
* new support for std::string_view

runtime/src/CMakeLists.txt

@@ -20,6 +20,8 @@ project(ZserioCpp17Runtime)
 set(ZSERIO_CPP17_RUNTIME_LIB_SRCS
     zserio/BuiltInOperators.cpp
     zserio/BuiltInOperators.h
+    zserio/CppRuntimeException.cpp
+    zserio/CppRuntimeException.h
     zserio/CppRuntimeVersion.h
     zserio/RebindAlloc.h
     zserio/Span.h

runtime/src/zserio/CppRuntimeException.cpp

@@ -0,0 +1,83 @@
+#include <algorithm>
+#include <array>
+#include <cstring>
+
+#include "zserio/CppRuntimeException.h"
+
+namespace zserio
+{
+
+CppRuntimeException::CppRuntimeException(const char* message) :
+        m_buffer()
+{
+    append(message);
+}
+
+const char* CppRuntimeException::what() const noexcept
+{
+    return m_buffer.data();
+}
+
+void CppRuntimeException::append(const char* message)
+{
+    const size_t available = m_buffer.size() - 1 - m_len;
+    const size_t numCharsToAppend = strnlen(message, available);
+    appendImpl(Span<const char>(message, numCharsToAppend));
+}
+
+void CppRuntimeException::append(const char* message, size_t messageLen)
+{
+    const size_t available = m_buffer.size() - 1 - m_len;
+    const size_t numCharsToAppend = std::min(messageLen, available);
+    appendImpl(Span<const char>(message, numCharsToAppend));
+}
+
+void CppRuntimeException::appendImpl(Span<const char> message)
+{
+    if (message.size() > 0)
+    {
+        (void)std::copy(message.begin(), message.end(), m_buffer.begin() + m_len);
+        m_len += message.size();
+    }
+    m_buffer.at(m_len) = '\0';
+}
+
+CppRuntimeException& operator<<(CppRuntimeException& exception, const char* message)
+{
+    exception.append(message);
+    return exception;
+}
+
+CppRuntimeException& operator<<(CppRuntimeException& exception, bool value)
+{
+    return exception << (value ? "true" : "false");
+}
+
+CppRuntimeException& operator<<(CppRuntimeException& exception, float value)
+{
+    std::array<char, 24> integerPartBuffer = {};
+    std::array<char, 24> floatingPartBuffer = {};
+    const char* integerPartString = nullptr;
+    const char* floatingPartString = nullptr;
+    convertFloatToString(integerPartBuffer, floatingPartBuffer, value, integerPartString, floatingPartString);
+    CppRuntimeException& result = exception << integerPartString;
+    if (floatingPartString != nullptr)
+    {
+        result = result << "." << floatingPartString;
+    }
+
+    return result;
+}
+
+CppRuntimeException& operator<<(CppRuntimeException& exception, double value)
+{
+    return exception << (static_cast<float>(value));
+}
+
+CppRuntimeException& operator<<(CppRuntimeException& exception, std::string_view value)
+{
+    exception.append(value.data(), value.size());
+    return exception;
+}
+
+} // namespace zserio

runtime/src/zserio/CppRuntimeException.h

@@ -0,0 +1,200 @@
+#ifndef ZSERIO_CPP_RUNTIME_EXCEPTION_H_INC
+#define ZSERIO_CPP_RUNTIME_EXCEPTION_H_INC
+
+#include <array>
+#include <exception>
+#include <string>
+#include <string_view>
+#include <type_traits>
+#include <vector>
+
+#include "zserio/Span.h"
+#include "zserio/StringConvertUtil.h"
+
+namespace zserio
+{
+
+/**
+ * Exception thrown when an error within the Zserio C++ runtime library occurs.
+ */
+class CppRuntimeException : public std::exception
+{
+public:
+    /**
+     * Constructor.
+     *
+     * \param message Description of the error.
+     */
+    explicit CppRuntimeException(const char* message = "");
+
+    /**
+     * Method generated by default.
+     * \{
+     */
+    ~CppRuntimeException() override = default;
+
+    CppRuntimeException(const CppRuntimeException& other) = default;
+    CppRuntimeException& operator=(const CppRuntimeException& other) = default;
+
+    CppRuntimeException(CppRuntimeException&& other) = default;
+    CppRuntimeException& operator=(CppRuntimeException&& other) = default;
+    /**
+     * \}
+     */
+
+    const char* what() const noexcept override;
+
+    /**
+     * Appends a message to the description.
+     *
+     * \param message Description of the error to append.
+     */
+    void append(const char* message);
+
+    /**
+     * Appends a message of a known length to the description.
+     *
+     * \param message Description of the error to append.
+     * \param messageLen Length of the message.
+     */
+    void append(const char* message, size_t messageLen);
+
+private:
+    void appendImpl(Span<const char> message);
+
+    std::array<char, 512> m_buffer; // note fixed sized array is deeply copied on copy operations and it's OK
+    size_t m_len = 0;
+};
+
+/**
+ * Appends a message to the exception's description.
+ *
+ * \param exception Exception to modify.
+ * \param message Description of the error to append.
+ *
+ * \return Reference to the exception to allow operator chaining.
+ */
+CppRuntimeException& operator<<(CppRuntimeException& exception, const char* message);
+
+/**
+ * Appends a bool value to the exception's description.
+ *
+ * \param exception Exception to modify.
+ * \param value Bool value to append.
+ *
+ * \return Reference to the exception to allow operator chaining.
+ */
+CppRuntimeException& operator<<(CppRuntimeException& exception, bool value);
+
+/**
+ * Appends a float value to the exception's description.
+ *
+ * \param exception Exception to modify.
+ * \param value Float value to append.
+ *
+ * \return Reference to the exception to allow operator chaining.
+ */
+CppRuntimeException& operator<<(CppRuntimeException& exception, float value);
+
+/**
+ * Appends a double value to the exception's description.
+ *
+ * \param exception Exception to modify.
+ * \param value Double value to append.
+ *
+ * \return Reference to the exception to allow operator chaining.
+ */
+CppRuntimeException& operator<<(CppRuntimeException& exception, double value);
+
+/**
+ * Appends a string_view to the exception's description.
+ *
+ * \param exception Exception to modify.
+ * \param value String view to append.
+ *
+ * \return Reference to the exception to allow operator chaining.
+ */
+CppRuntimeException& operator<<(CppRuntimeException& exception, std::string_view value);
+
+/**
+ * Appends an integral value to the exception's description.
+ *
+ * \param exception Exception to modify.
+ * \param value Integral value to append.
+ *
+ * \return Reference to the exception to allow operator chaining.
+ */
+template <typename T, typename std::enable_if<std::is_integral<T>::value, int>::type = 0>
+CppRuntimeException& operator<<(CppRuntimeException& exception, T value)
+{
+    std::array<char, 24> buffer = {};
+    const char* stringValue = convertIntToString(buffer, value);
+    return exception << stringValue;
+}
+
+/**
+ * Appends a string value to the exception's description.
+ *
+ * \param exception Exception to modify.
+ * \param value String value to append.
+ *
+ * \return Reference to the exception to allow operator chaining.
+ */
+template <typename ALLOC>
+CppRuntimeException& operator<<(
+        CppRuntimeException& exception, const std::basic_string<char, std::char_traits<char>, ALLOC>& value)
+{
+    exception.append(value.c_str(), value.size());
+    return exception;
+}
+
+/**
+ * Appends a vector value to the exception's description.
+ *
+ * \param exception Exception to modify.
+ * \param value Vector value to append.
+ *
+ * \return Reference to the exception to allow operator chaining.
+ */
+template <typename T, typename ALLOC>
+CppRuntimeException& operator<<(CppRuntimeException& exception, const std::vector<T, ALLOC>& value)
+{
+    return exception << "vector([...], " << value.size() << ")";
+}
+
+namespace detail
+{
+
+// inspired by C++ ostreams - see https://cplusplus.github.io/LWG/issue1203
+// note that e.g. in gcc implementation of ostreams there are two constraints, but the second one:
+//      typename = decltype(std::declval<EXCEPTION&>() << std::declval<const VALUE&>())
+// is probably unnecessary and since it caused a compilation error in MSVC 2017 Conformance Mode,
+// we intentionally skipped it (even though it was probably a compiler bug)
+template <typename EXCEPTION, typename VALUE,
+        typename = typename std::enable_if<std::is_base_of<CppRuntimeException, EXCEPTION>::value, int>::type>
+using CppRuntimeExceptionRValueInsertion = EXCEPTION&&;
+
+} // namespace detail
+
+/**
+ * Appends any value for which operator<< is implemented to the exception's description.
+ *
+ * Overload for rvalue to enable operator<< on a temporary object, .e.g. CppRuntimeException() << "value".
+ * Moreover note that this overload preserves the concrete type of the exception!
+ *
+ * \param exception Exception to modify.
+ * \param value Value to append.
+ *
+ * \return R-value reference to the original exception to allow operator chaining.
+ */
+template <typename CPP_RUNTIME_EXCEPTION, typename T>
+detail::CppRuntimeExceptionRValueInsertion<CPP_RUNTIME_EXCEPTION, T> operator<<(
+        CPP_RUNTIME_EXCEPTION&& exception, const T& value)
+{
+    exception << value;
+    return std::forward<CPP_RUNTIME_EXCEPTION>(exception);
+}
+
+} // namespace zserio
+
+#endif // ifndef ZSERIO_CPP_RUNTIME_EXCEPTION_H_INC

runtime/test/CMakeLists.txt

@@ -13,6 +13,7 @@ gtest_add_library("${ZSERIO_CPP17_PROJECT_ROOT}/3rdparty/cpp/googletest")
 
 set(ZSERIO_CPP17_RUNTIME_TEST_SRCS
     zserio/BuiltInOperatorsTest.cpp
+    zserio/CppRuntimeExceptionTest.cpp
     zserio/CppRuntimeVersionTest.cpp
     zserio/SpanTest.cpp
     zserio/StringConvertUtilTest.cpp