From 2b37d7ed86926f0c7c865651b4dee29aaae2015b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Th=C3=A9o=20DELRIEU?= <theo.delrieu@tanker.io>
Date: Mon, 18 Jun 2018 10:53:30 +0200
Subject: [PATCH] from_json: add overload for std::unordered_map
Fixes #1133
---
.../nlohmann/detail/conversions/from_json.hpp | 20 ++++++++
test/src/unit-conversions.cpp | 50 +++++++++++++++++--
2 files changed, 66 insertions(+), 4 deletions(-)
diff --git a/include/nlohmann/detail/conversions/from_json.hpp b/include/nlohmann/detail/conversions/from_json.hpp
index e77ad5d2..7fe19f57 100644
--- a/include/nlohmann/detail/conversions/from_json.hpp
+++ b/include/nlohmann/detail/conversions/from_json.hpp
@@ -9,6 +9,7 @@
#include <string> // string
#include <tuple> // tuple, make_tuple
#include <type_traits> // is_arithmetic, is_same, is_enum, underlying_type, is_convertible
+#include <unordered_map> // unordered_map
#include <utility> // pair, declval
#include <valarray> // valarray
@@ -297,6 +298,25 @@ void from_json(const BasicJsonType& j, std::map<Key, Value, Compare, Allocator>&
}
}
+template <typename BasicJsonType, typename Key, typename Value, typename Hash, typename KeyEqual, typename Allocator,
+ typename = enable_if_t<not std::is_constructible<
+ typename BasicJsonType::string_t, Key>::value>>
+void from_json(const BasicJsonType& j, std::unordered_map<Key, Value, Hash, KeyEqual, Allocator>& m)
+{
+ if (JSON_UNLIKELY(not j.is_array()))
+ {
+ JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(j.type_name())));
+ }
+ for (const auto& p : j)
+ {
+ if (JSON_UNLIKELY(not p.is_array()))
+ {
+ JSON_THROW(type_error::create(302, "type must be array, but is " + std::string(p.type_name())));
+ }
+ m.emplace(p.at(0).template get<Key>(), p.at(1).template get<Value>());
+ }
+}
+
struct from_json_fn
{
private:
diff --git a/test/src/unit-conversions.cpp b/test/src/unit-conversions.cpp
index 79ccf681..0691bbf4 100644
--- a/test/src/unit-conversions.cpp
+++ b/test/src/unit-conversions.cpp
@@ -40,6 +40,14 @@ using nlohmann::json;
#include <unordered_set>
#include <valarray>
+namespace
+{
+template <typename MapType>
+void map_type_conversion_checks()
+{
+}
+}
+
TEST_CASE("value conversion")
{
SECTION("get an object (explicit)")
@@ -1088,14 +1096,48 @@ TEST_CASE("value conversion")
CHECK(m == m2);
json j7 = {0, 1, 2, 3};
+ json j8 = 2;
CHECK_THROWS_AS((j7.get<std::map<int, int>>()), json::type_error&);
- CHECK_THROWS_WITH((j7.get<std::map<int, int>>()), "[json.exception.type_error.302] type must be array, but is number");
+ CHECK_THROWS_AS((j8.get<std::map<int, int>>()), json::type_error&);
+ CHECK_THROWS_WITH((j7.get<std::map<int, int>>()),
+ "[json.exception.type_error.302] type must be array, "
+ "but is number");
+ CHECK_THROWS_WITH((j8.get<std::map<int, int>>()),
+ "[json.exception.type_error.302] type must be array, "
+ "but is number");
SECTION("superfluous entries")
{
- json j8 = {{0, 1, 2}, {1, 2, 3}, {2, 3, 4}};
- m2 = j8.get<std::map<int, int>>();
- CHECK(m == m2);
+ json j9 = {{0, 1, 2}, {1, 2, 3}, {2, 3, 4}};
+ m2 = j9.get<std::map<int, int>>();
+ CHECK(m == m2);
+ }
+ }
+
+ SECTION("std::unordered_map (array of pairs)")
+ {
+ std::unordered_map<int, int> m{{0, 1}, {1, 2}, {2, 3}};
+ json j6 = m;
+
+ auto m2 = j6.get<std::unordered_map<int, int>>();
+ CHECK(m == m2);
+
+ json j7 = {0, 1, 2, 3};
+ json j8 = 2;
+ CHECK_THROWS_AS((j7.get<std::unordered_map<int, int>>()), json::type_error&);
+ CHECK_THROWS_AS((j8.get<std::unordered_map<int, int>>()), json::type_error&);
+ CHECK_THROWS_WITH((j7.get<std::unordered_map<int, int>>()),
+ "[json.exception.type_error.302] type must be array, "
+ "but is number");
+ CHECK_THROWS_WITH((j8.get<std::unordered_map<int, int>>()),
+ "[json.exception.type_error.302] type must be array, "
+ "but is number");
+
+ SECTION("superfluous entries")
+ {
+ json j9{{0, 1, 2}, {1, 2, 3}, {2, 3, 4}};
+ m2 = j9.get<std::unordered_map<int, int>>();
+ CHECK(m == m2);
}
}