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Overview

CryENGINE has a custom reference-counted string class CryString (declared in CryString.h) which is a replacement for the STL std::string. It should always be preferred over std::string. For convenience, string is used as a typedef for CryString.

How to Use Strings as Key Values for STL Containers

The following code shows good (efficient) and bad usage:

const char *szKey= "Test";

map< string, int >::const_iterator iter = m_values.find( CONST_TEMP_STRING( szKey ) );   // Good way

map< string, int >::const_iterator iter = m_values.find( szKey );  // Bad way, don't do it like this!

By using the suggested method, you avoid allocation/deallocation and copying for a temporary string object. This is a common problem for most string classes. By simply using the macro CONST_TEMP_STRING, we trick the string class to use the pointer directly without freeing the data afterwards.

Further Usage Tips

  • Do not use std::string or std::wstring, just string and wstring and never include the standard string header <string>.
  • Use the c_str() method to access the contents of the string.
  • Never modify memory returned by the c_str() method since strings are reference-counted and a wrong string instance could be affected.
  • Do not pass strings via abstract interfaces; all interfaces should use const char* in interface methods.
  • CryString has a combined interface of std::string and MFC CString, so both interface types can be used for string operations.
  • Avoid doing many string operations at run-time as they are often causing memory reallocations.
  • For fixed size strings (e.g. 256 chars) use CryFixedStringT (should be preferred over static char arrays).
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