Fix `riegeli::Compare()` emulating `<=>` before C++20 for pointers: * Use `std::less<T*>` semantics rather than `<`. * Allow heterogeneous comparisons of compatible pointer types. Add support for ordering `SharedPtr` and `IntrusiveSharedPtr`. They follow `std::shared_ptr` and `std::unique_ptr`: like for raw pointers, but also allowing comparisons against `nullptr` of type `std::nullptr_t`. This means that ordering is supported, while all heterogeneous comparisons require compatible pointer types. Add support for hashing `SharedPtr` and `IntrusiveSharedPtr`. PiperOrigin-RevId: 918408947
Riegeli/records is a file format for storing a sequence of string records, typically serialized protocol buffers. It supports dense compression, fast decoding, seeking, detection and optional skipping of data corruption, filtering of proto message fields for even faster decoding, and parallel encoding.
See documentation.
Riegeli file format will only change in a backward compatible way (i.e. future readers will understand current files, but current readers might not understand files using future features).
Riegeli C++ API might change in incompatible ways.