Rewrite of flexible type converter logic.

oss_src/flexible_type/flexible_type_conversion_utilities.hpp

@@ -0,0 +1,114 @@
+/**
+ * Copyright (C) 2015 Dato, Inc.
+ * All rights reserved.
+ *
+ * This software may be modified and distributed under the terms
+ * of the BSD license. See the LICENSE file for details.
+ */
+
+#ifndef GRAPHLAB_FLEXIBLE_TYPE_FLEXIBLE_TYPE_CONVERSION_UTILS_HPP
+#define GRAPHLAB_FLEXIBLE_TYPE_FLEXIBLE_TYPE_CONVERSION_UTILS_HPP
+
+#include <vector>
+#include <map>
+#include <unordered_map>
+#include <tuple>
+#include <type_traits>
+#include <util/code_optimization.hpp>
+#include <flexible_type/flexible_type.hpp>
+#include <flexible_type/type_traits.hpp>
+
+namespace graphlab {
+
+namespace flexible_type_internals {
+
+static void throw_type_conversion_error(const flexible_type& val, const char *type) {
+  std::ostringstream ss;
+  ss << "Type conversion failure in flexible_type converter: expected "
+     << type << "; got " << flex_type_enum_to_name(val.get_type());
+
+  throw ss.str();
+}
+
+template <typename Arg>
+static void __unpack_args(std::ostringstream& ss, Arg a) {
+  ss << a;
+}
+
+template <typename Arg, typename... OtherArgs>
+static void __unpack_args(std::ostringstream& ss, Arg a1, OtherArgs... a2) {
+  ss << a1;
+  __unpack_args(ss, a2...);
+}
+
+template <typename... PrintArgs>
+static void throw_type_conversion_error(const flexible_type& val, const char* type, PrintArgs... args) {
+  std::ostringstream ss;
+  ss << "Type conversion failure in flexible_type converter: expected " << type;
+  __unpack_args(ss, args...);
+  ss << "; got " << flex_type_enum_to_name(val.get_type());
+
+  throw ss.str();
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+template <typename T>
+static void __get_t(flexible_type& dest, const T& src) {
+  convert_to_flexible_type(dest, src);
+}
+
+template <typename T>
+static void __get_t(double& dest, const T& src) {
+  dest = src;
+}
+
+template <size_t idx, typename C, typename... Args>
+void __unpack_tuple(C& dest, const std::tuple<Args...>& src,
+                    typename std::enable_if<idx == sizeof...(Args)>::type* = NULL) {}
+
+template <size_t idx, typename C, typename... Args>
+void __unpack_tuple(C& dest, const std::tuple<Args...>& src,
+                    typename std::enable_if<idx != sizeof...(Args)>::type* = NULL) {
+   __get_t(dest[idx], std::get<idx>(src));
+   __unpack_tuple<idx + 1>(dest, src);
+}
+
+template <typename C, typename... Args>
+static void unpack_tuple(C& dest, const std::tuple<Args...>& src) {
+   __unpack_tuple<0>(dest, src);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
+
+template <typename T>
+static void __set_t(T& dest, const flexible_type& src) {
+  convert_from_flexible_type(dest, src);
+}
+
+template <typename T>
+static void __set_t(T& dest, double src) {
+  dest = static_cast<T>(src);
+}
+
+template <size_t idx, typename C, typename... Args>
+void __pack_tuple(std::tuple<Args...>& dest, const C& src,
+                    typename std::enable_if<idx == sizeof...(Args)>::type* = NULL) {}
+
+template <size_t idx, typename C, typename... Args>
+void __pack_tuple(std::tuple<Args...>& dest, const C& src,
+                    typename std::enable_if<idx != sizeof...(Args)>::type* = NULL) {
+   __set_t(std::get<idx>(dest), src[idx]);
+   __pack_tuple<idx + 1>(dest, src);
+}
+
+template <typename C, typename... Args>
+static void pack_tuple(std::tuple<Args...>& dest, const C& src) {
+   __pack_tuple<0>(dest, src);
+}
+
+}}
+
+
+#endif