Merge pull request ClickHouse#37 from v5r/enum-iter

provide iterator for enum elements

Author: artpaul

clickhouse/types/types.cpp

@@ -212,4 +212,12 @@ bool EnumType::HasEnumValue(int16_t value) const {
     return type_->enum_->value_to_name.find(value) != type_->enum_->value_to_name.end();
 }
 
+EnumType::ValueToNameIterator EnumType::BeginValueToName() const {
+    return type_->enum_->value_to_name.begin();
+}
+
+EnumType::ValueToNameIterator EnumType::EndValueToName() const {
+    return type_->enum_->value_to_name.end();
+}
+
 }

clickhouse/types/types.h

@@ -98,8 +98,10 @@ class Type {
     };
 
     struct EnumImpl {
-        std::map<int16_t, std::string> value_to_name;
-        std::map<std::string, int16_t> name_to_value;
+        using ValueToNameType = std::map<int16_t, std::string>;
+        using NameToValueType = std::map<std::string, int16_t>;
+        ValueToNameType value_to_name;
+        NameToValueType name_to_value;
     };
 
     friend class EnumType;
@@ -128,6 +130,11 @@ class EnumType {
     bool HasEnumName(const std::string& name) const;
     bool HasEnumValue(int16_t value) const;
 
+    /// Iterator for enum elements.
+    using ValueToNameIterator = Type::EnumImpl::ValueToNameType::const_iterator;
+    ValueToNameIterator BeginValueToName() const;
+    ValueToNameIterator EndValueToName() const;
+
 private:
     TypeRef type_;
 };

ut/types_ut.cpp

@@ -58,4 +58,10 @@ TEST(TypesCase, EnumTypes) {
     ASSERT_FALSE(enum16.HasEnumName("Black"));
     ASSERT_EQ(enum16.GetEnumName(2), "Red");
     ASSERT_EQ(enum16.GetEnumValue("Green"), 1);
+
+    ASSERT_EQ(std::distance(enum16.BeginValueToName(), enum16.EndValueToName()), 3u);
+    ASSERT_EQ((*enum16.BeginValueToName()).first, 1);
+    ASSERT_EQ((*enum16.BeginValueToName()).second, "Green");
+    ASSERT_EQ((*(++enum16.BeginValueToName())).first, 2);
+    ASSERT_EQ((*(++enum16.BeginValueToName())).second, "Red");
 }