This library adds simple and efficient indexed strings for C++ and Unity.

An Indexed String is a data type that represents an String but is faster to compare and copy, and is smaller in memory. However, it is slightly more expensive to create.

Both in Cpp and Unity you will find the struct IdString. It can be created from an string and doesn't need any setup.

When an IdString is created or assigned from an string or const char*, its hash value is stored and a copy of the string is saved on a global table.

That is why an IdString only needs 8 bytes, and why comparing it is very fast (we are only checking that two integers match).

To return the string value, the table will find the hash we have and return it as a const String&. If the IdString was null, then the returned string is an static none value. This is done to avoid copying any strings.

Because of its size (8 bytes), it is recommended that this type is always passed by value and copied.

In Cpp serialization is not implemented in favor of any custom solution the user may have. It's recommended to store it as an string value.

In Unity an IdString is serialized as an string directly. (It also has the benefit that debugging it it considerably easier)

IdStrings have support for Multithreading. They can be created from different threads without conflicts. This is done using shared_mutex. That way the library only locks while registering a new string, but not while reading.

• If a new string is registered, it locks all reads
• If an already existing string is registered, it won't lock reads
• Reads won't lock unless a registry arrives at the same time

Registering an string is a very quick and uncommon operation so in the majority of the cases mutex won't even be locked and other threads wont be delayed.

There's one single main feature missing which is the removal of unused strings from the table. This is usually not a problem because strings are never duplicated on the table, but if we are constantly generating different names, the table won't free them.

The associated Unity project has tests for this library:

Developed for ESNE Development and Design of Videogames degree by Miguel Fernández Arce.