struct std::hash< ara::core::String >

The specialization std::hash< ara::core::String > serves to calculate integer hash values for instances of ara::core::String in module core. It enables the seamless integration of the Adaptive string type into unordered standard containers. As a stateless function object declared as final, it does not possess a complex lifecycle and merely requires a valid character string for deterministic evaluation.

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Context

The structure std::hash< ara::core::String > represents a template specialization of the standardized C++ function class std::hash for the type ara::core::String within module core of the Adaptive Platform. In accordance with the general architecture of C++ standard libraries, it serves as a hash function object that maps string instances to integer hash values. Typical interaction partners are associative standard containers, such as unordered sets or maps, which rely on standardized hash interfaces for rapid indexing and distribution of elements. The declaration is specified as final, precluding any further derivation from this specialization.

Interpretation: Since no explicit requirements or document references are stored in the present specification excerpt, the role of the specialization is likely to fit seamlessly into the conventional standard library semantics of std::hash and primarily serve the interoperability between ara::core::String and hash-based data structures. Question Q-6d2835413a6e35a5 (open)

Lifecycle

As a stateless function object, std::hash< ara::core::String > is not subject to complex lifecycle phases or dynamic state transitions. Instances of the structure can be instantiated as needed or created as temporary function objects and destroyed immediately after the calculation. No persistent ownership of the passed strings exists. Because the structure is stateless, invoking the function operator for const instances of ara::core::String is likely to be inherently concurrency-safe and thread-safe, provided the underlying string is not modified concurrently during hash calculation. Question Q-bec5dd50aaf196d9 (open)

Usage Path

Regular use of std::hash< ara::core::String > occurs either implicitly via associative containers or through explicit instantiation to determine the hash value of a character string:

• Creation or referencing of a valid instance of ara::core::String.
• Instantiation of the function object std::hash< ara::core::String > or implicit use as a default hash parameter in unordered standard containers.
• Execution of the call operator while passing the character string to return the calculated hash value.

Interpretation: The sequence presumably follows the usual pattern for C++ function objects without additional configuration or initialization steps. Question (open)

Error Scenarios

Calculation of the hash value requires that the passed string instance ara::core::String is valid. Error states or specific error codes in the sense of ara::core::ErrorCode are not designated in the payload for this specialization. Based on standard requirements for hash functions, it can be assumed that the calculation is performed deterministically and regularly throws no exceptions, provided that access to the memory area of the string is guaranteed.