Inefficient output stream operator implementation #38

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1. chronoxor commented on Dec 15, 2020

   

   chronoxor

   on Dec 15, 2020

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   FBE protocol spec allows to declare enums with duplicate values:

   // Byte enum declaration
   enum EnumByte : byte
   {
       ENUM_VALUE_0;
       ENUM_VALUE_1 = 0;
       ENUM_VALUE_2;
       ENUM_VALUE_3 = 254;
       ENUM_VALUE_4;
       ENUM_VALUE_5 = ENUM_VALUE_3;
   }
   

   In this case switch statement will generate:
   error C2196: case value 'enums::EnumByte::ENUM_VALUE_0' already used
error C2196: case value 'enums::EnumByte::ENUM_VALUE_3' already used
2. chronoxor commented on Dec 15, 2020

   

   chronoxor

   on Dec 15, 2020

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   Enum value string is rarely used outside struct's dumps in logs. So << operator is more suitable. In case you need string equivalent try:

   std::string to_string(EnumByte value) const { std::stringstream ss; ss << value; return ss.str(); }
   
3. herolover commented on Dec 15, 2020

   

   herolover

   on Dec 15, 2020

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   FBE protocol spec allows to declare enums with duplicate values:

   // Byte enum declaration
   enum EnumByte : byte
   {
       ENUM_VALUE_0;
       ENUM_VALUE_1 = 0;
       ENUM_VALUE_2;
       ENUM_VALUE_3 = 254;
       ENUM_VALUE_4;
       ENUM_VALUE_5 = ENUM_VALUE_3;
   }
   

   In this case switch statement will generate:
   error C2196: case value 'enums::EnumByte::ENUM_VALUE_0' already used
error C2196: case value 'enums::EnumByte::ENUM_VALUE_3' already used

   So it means only an alias. And it could be handled, couldn't it? Ok, I just wanted to point it out.

   Enum value string is rarely used outside struct's dumps in logs. So << operator is more suitable. In case you need string equivalent try:

   std::string to_string(EnumByte value) const { std::stringstream ss; ss << value; return ss.str(); }
   

   Yes, such cases are rare, but they are. This way(using std::stringstream) has a huge overhead(comparing to getting const char * from switch statement).
4. bitbugprime commented on Feb 8, 2021

   

   bitbugprime

   on Feb 8, 2021

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   Yes, such cases are rare, but they are. This way(using std::stringstream) has a huge overhead(comparing to getting const char * from switch statement).

   Since this is a C++17 library, an std::string_view would be a more appropriate return type.

   👍React with 👍1Reacted by Anton Zhvakin