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WPILibC++
2020.3.2
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A discriminated union of two pointer types, with the discriminator in the low bit of the pointer. More...
#include <PointerUnion.h>
Public Types | |
| using | ValTy = PointerIntPair< void *, 1, bool, PointerUnionUIntTraits< PT1, PT2 > > |
Public Member Functions | |
| PointerUnion (PT1 V) | |
| PointerUnion (PT2 V) | |
| bool | isNull () const |
| Test if the pointer held in the union is null, regardless of which type it is. | |
| operator bool () const | |
| template<typename T > | |
| int | is () const |
| Test if the Union currently holds the type matching T. | |
| template<typename T > | |
| T | get () const |
| Returns the value of the specified pointer type. More... | |
| template<typename T > | |
| T | dyn_cast () const |
| Returns the current pointer if it is of the specified pointer type, otherwises returns null. | |
| const PT1 * | getAddrOfPtr1 () const |
| If the union is set to the first pointer type get an address pointing to it. | |
| PT1 * | getAddrOfPtr1 () |
| If the union is set to the first pointer type get an address pointing to it. | |
| const PointerUnion & | operator= (std::nullptr_t) |
| Assignment from nullptr which just clears the union. | |
| const PointerUnion & | operator= (const PT1 &RHS) |
| Assignment operators - Allow assigning into this union from either pointer type, setting the discriminator to remember what it came from. | |
| const PointerUnion & | operator= (const PT2 &RHS) |
| void * | getOpaqueValue () const |
Static Public Member Functions | |
| static PointerUnion | getFromOpaqueValue (void *VP) |
A discriminated union of two pointer types, with the discriminator in the low bit of the pointer.
This implementation is extremely efficient in space due to leveraging the low bits of the pointer, while exposing a natural and type-safe API.
Common use patterns would be something like this: PointerUnion<int*, float*> P; P = (int*)0; printf("%d %d", P.is<int*>(), P.is<float*>()); // prints "1 0" X = P.get<int*>(); // ok. Y = P.get<float*>(); // runtime assertion failure. Z = P.get<double*>(); // compile time failure. P = (float*)0; Y = P.get<float*>(); // ok. X = P.get<int*>(); // runtime assertion failure.
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inline |
Returns the value of the specified pointer type.
If the specified pointer type is incorrect, assert.