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69 lines
2.1 KiB
C
69 lines
2.1 KiB
C
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// This code is in the public domain -- Ignacio Casta<74>o <castano@gmail.com>
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#pragma once
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#ifndef NV_CORE_FOREACH_H
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#define NV_CORE_FOREACH_H
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/*
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These foreach macros are very non-standard and somewhat confusing, but I like them.
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*/
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#include "nvcore.h"
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#if NV_CC_GNUC // If typeof or decltype is available:
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#if !NV_CC_CPP11
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# define NV_DECLTYPE typeof // Using a non-standard extension over typeof that behaves as C++11 decltype
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#else
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# define NV_DECLTYPE decltype
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#endif
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/*
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Ideally we would like to write this:
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#define NV_FOREACH(i, container) \
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for(NV_DECLTYPE(container)::PseudoIndex i((container).start()); !(container).isDone(i); (container).advance(i))
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But gcc versions prior to 4.7 required an intermediate type. See:
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https://gcc.gnu.org/bugzilla/show_bug.cgi?id=6709
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*/
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#define NV_FOREACH(i, container) \
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typedef NV_DECLTYPE(container) NV_STRING_JOIN2(cont,__LINE__); \
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for(NV_STRING_JOIN2(cont,__LINE__)::PseudoIndex i((container).start()); !(container).isDone(i); (container).advance(i))
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#else // If typeof not available:
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#include <new> // placement new
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struct PseudoIndexWrapper {
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template <typename T>
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PseudoIndexWrapper(const T & container) {
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nvStaticCheck(sizeof(typename T::PseudoIndex) <= sizeof(memory));
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new (memory) typename T::PseudoIndex(container.start());
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}
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// PseudoIndex cannot have a dtor!
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template <typename T> typename T::PseudoIndex & operator()(const T * /*container*/) {
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return *reinterpret_cast<typename T::PseudoIndex *>(memory);
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}
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template <typename T> const typename T::PseudoIndex & operator()(const T * /*container*/) const {
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return *reinterpret_cast<const typename T::PseudoIndex *>(memory);
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}
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uint8 memory[4]; // Increase the size if we have bigger enumerators.
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};
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#define NV_FOREACH(i, container) \
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for(PseudoIndexWrapper i(container); !(container).isDone(i(&(container))); (container).advance(i(&(container))))
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#endif
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// Declare foreach keyword.
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#if !defined NV_NO_USE_KEYWORDS
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# define foreach NV_FOREACH
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# define foreach_index NV_FOREACH
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#endif
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#endif // NV_CORE_FOREACH_H
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