OSL_ALLOCA #1589
OSL_ALLOCA #1589
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We use OIIO_ALLOCA in many places. Make an OSL version and put it in platform.h. Signed-off-by: Larry Gritz <lg@larrygritz.com>
src/include/OSL/platform.h
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| /// things of bounded size, but not for anything that could be arbitrarily | ||
| /// big, which should instead use heap allocation. | ||
| #if defined(__GNUC__) | ||
| # define OSL_ALLOCA(type, size) (assert(size < (1<<20)), (size) != 0 ? ((type*)__builtin_alloca((size) * sizeof(type))) : nullptr) |
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Any style guidelines here for casting? Should it be
(reinterpret_cast<type*>(__builtin_alloca((size) * sizeof(type))))
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I think I am just an old programmer whose fingers tend to reflexively use C casts and forget about the C++ style until somebody points out my error. To be honest, I don't really feel that there are many places where the more verbose C++ syntax confers any advantage in practice.
I understand their purpose and see the point: const_cast only casts away constness while changing nothing else, static_cast is a value conversion from one type to another, reinterpret_cast turns a pointer into a different pointer type (but referring to the same memory). The use of the right specialized cast is a semantic breadcrumb conveying intent, whereas the C (cast) style is just a big hammer that clobbers everything. But the return value of alloca is already just raw memory that is semantic-free, so there's nothing to clobber, it's a truly arbitrary cast. In this case, what does reinterpret_cast<type*> do or what information does it convey that (type*) does not?
I'm just thinking out loud. I have no objection to the suggestion to change this to more idiomatic C++.
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To be clear, I don't have any objection to the old C cast, just using C++ as a matter of habit and was curious if there was a style guideline in practice for the project. Although I think I like the in your face verbosity of the reinterpret_cast<>() and the wrapping parenthesis around the item to cast.
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I did update with the new style cast
Signed-off-by: Larry Gritz <lg@larrygritz.com>
We use OIIO_ALLOCA in many places. Make an OSL version and put it in platform.h. Signed-off-by: Larry Gritz <lg@larrygritz.com>
We use OIIO_ALLOCA in many places. Make an OSL version and put it in platform.h.
Signed-off-by: Larry Gritz lg@larrygritz.com