State: Use std::vector
#97
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The vectors in `State` are never memory-mapped, so we can use `std::vector` instead of Marisa's vector. `std::vector` is smaller in size. This reduces `State` size from 80 bytes to 64 bytes, making it fit into a single cache line.
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Perhaps in a future PR we can merge |
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Please wait. |
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I think the only exception it can throw is |
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I was also wondering what the advantage of using |
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I cannot remember the details. Even if the design is strange, we should not change the behavior for compatibility. |
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I've added exception rethrowing. It increases For a major version bump, I think it'd be useful to consider not having this custom behaviour. Most code out there doesn't customize exceptions from the standard library this way, so it can be unexpected. For example, in the rare situation where a program actually handles allocation failure, there is usually an |
| #ifndef MARISA_USE_EXCEPTIONS | ||
| #if defined(__GNUC__) && !defined(__EXCEPTIONS) | ||
| #define MARISA_USE_EXCEPTIONS 0 | ||
| #elif defined(__clang__) && !defined(__cpp_exceptions) | ||
| #define MARISA_USE_EXCEPTIONS 0 | ||
| #elif defined(_MSC_VER) && !_HAS_EXCEPTIONS | ||
| #define MARISA_USE_EXCEPTIONS 0 | ||
| #else | ||
| #define MARISA_USE_EXCEPTIONS 1 | ||
| #endif | ||
| #endif |
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Do you assume an environment that disallows exceptions?
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This supports such environments on GCC, Clang, and MSVC.
Exceptions are commonly disabled in environments such as Google and game development.
It is usually possible to compile individual libraries with exception support in these environments (as long as there is no exception handling in public headers) but it's pointless to catch-and-rethrow in this case.
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Thank you for the information.
I didn't know this.
If exceptions are disabled, an application is terminated by an exception?
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Yes, if exceptions are disabled, then throwing an exception terminates the program.
Internally at Google we use explicit error handling with absl::Status (std::expected is the standard library equivalent in C++23).
There is generally no sensible way to handle things like out-of-memory errors or internal logic errors, so we do not try to handle them and simply allow the program to crash in those cases.
The vectors in
Stateare never memory-mapped, so we can usestd::vectorinstead of Marisa's vector.std::vectoris smaller in size (24 bytes vs 32 bytes).This reduces
Statesize from 80 bytes to 64 bytes, making it fit into a single cache line.Benchmark on my machine shows a tiny improvement on a large file (best run of 3, so could just be noise):
Before:
After: