WPILibC++  2020.3.2
PointerUnion.h
1 //===- llvm/ADT/PointerUnion.h - Discriminated Union of 2 Ptrs --*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file defines the PointerUnion class, which is a discriminated union of
11 // pointer types.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef WPIUTIL_WPI_POINTERUNION_H
16 #define WPIUTIL_WPI_POINTERUNION_H
17 
18 #include "wpi/DenseMapInfo.h"
19 #include "wpi/PointerIntPair.h"
20 #include "wpi/PointerLikeTypeTraits.h"
21 #include <cassert>
22 #include <cstddef>
23 #include <cstdint>
24 
25 namespace wpi {
26 
27 template <typename T> struct PointerUnionTypeSelectorReturn {
28  using Return = T;
29 };
30 
40 template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
42  using Return = typename PointerUnionTypeSelectorReturn<RET_NE>::Return;
43 };
44 
45 template <typename T, typename RET_EQ, typename RET_NE>
46 struct PointerUnionTypeSelector<T, T, RET_EQ, RET_NE> {
47  using Return = typename PointerUnionTypeSelectorReturn<RET_EQ>::Return;
48 };
49 
50 template <typename T1, typename T2, typename RET_EQ, typename RET_NE>
52  PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>> {
53  using Return =
54  typename PointerUnionTypeSelector<T1, T2, RET_EQ, RET_NE>::Return;
55 };
56 
59 template <typename PT1, typename PT2> class PointerUnionUIntTraits {
60 public:
61  static inline void *getAsVoidPointer(void *P) { return P; }
62  static inline void *getFromVoidPointer(void *P) { return P; }
63 
64  enum {
67  NumLowBitsAvailable = PT1BitsAv < PT2BitsAv ? PT1BitsAv : PT2BitsAv
68  };
69 };
70 
87 template <typename PT1, typename PT2> class PointerUnion {
88 public:
89  using ValTy =
91 
92 private:
93  ValTy Val;
94 
95  struct IsPT1 {
96  static const int Num = 0;
97  };
98  struct IsPT2 {
99  static const int Num = 1;
100  };
101  template <typename T> struct UNION_DOESNT_CONTAIN_TYPE {};
102 
103 public:
104  PointerUnion() = default;
105  PointerUnion(PT1 V)
106  : Val(const_cast<void *>(
108  PointerUnion(PT2 V)
109  : Val(const_cast<void *>(PointerLikeTypeTraits<PT2>::getAsVoidPointer(V)),
110  1) {}
111 
114  bool isNull() const {
115  // Convert from the void* to one of the pointer types, to make sure that
116  // we recursively strip off low bits if we have a nested PointerUnion.
117  return !PointerLikeTypeTraits<PT1>::getFromVoidPointer(Val.getPointer());
118  }
119 
120  explicit operator bool() const { return !isNull(); }
121 
123  template <typename T> int is() const {
124  using Ty = typename ::wpi::PointerUnionTypeSelector<
125  PT1, T, IsPT1,
126  ::wpi::PointerUnionTypeSelector<PT2, T, IsPT2,
127  UNION_DOESNT_CONTAIN_TYPE<T>>>::Return;
128  int TyNo = Ty::Num;
129  return static_cast<int>(Val.getInt()) == TyNo;
130  }
131 
135  template <typename T> T get() const {
136  assert(is<T>() && "Invalid accessor called");
137  return PointerLikeTypeTraits<T>::getFromVoidPointer(Val.getPointer());
138  }
139 
142  template <typename T> T dyn_cast() const {
143  if (is<T>())
144  return get<T>();
145  return T();
146  }
147 
150  PT1 const *getAddrOfPtr1() const {
151  return const_cast<PointerUnion *>(this)->getAddrOfPtr1();
152  }
153 
156  PT1 *getAddrOfPtr1() {
157  assert(is<PT1>() && "Val is not the first pointer");
158  assert(
159  get<PT1>() == Val.getPointer() &&
160  "Can't get the address because PointerLikeTypeTraits changes the ptr");
161  return const_cast<PT1 *>(
162  reinterpret_cast<const PT1 *>(Val.getAddrOfPointer()));
163  }
164 
166  const PointerUnion &operator=(std::nullptr_t) {
167  Val.initWithPointer(nullptr);
168  return *this;
169  }
170 
173  const PointerUnion &operator=(const PT1 &RHS) {
174  Val.initWithPointer(
175  const_cast<void *>(PointerLikeTypeTraits<PT1>::getAsVoidPointer(RHS)));
176  return *this;
177  }
178  const PointerUnion &operator=(const PT2 &RHS) {
179  Val.setPointerAndInt(
180  const_cast<void *>(PointerLikeTypeTraits<PT2>::getAsVoidPointer(RHS)),
181  1);
182  return *this;
183  }
184 
185  void *getOpaqueValue() const { return Val.getOpaqueValue(); }
186  static inline PointerUnion getFromOpaqueValue(void *VP) {
187  PointerUnion V;
188  V.Val = ValTy::getFromOpaqueValue(VP);
189  return V;
190  }
191 };
192 
193 template <typename PT1, typename PT2>
194 bool operator==(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
195  return lhs.getOpaqueValue() == rhs.getOpaqueValue();
196 }
197 
198 template <typename PT1, typename PT2>
199 bool operator!=(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
200  return lhs.getOpaqueValue() != rhs.getOpaqueValue();
201 }
202 
203 template <typename PT1, typename PT2>
204 bool operator<(PointerUnion<PT1, PT2> lhs, PointerUnion<PT1, PT2> rhs) {
205  return lhs.getOpaqueValue() < rhs.getOpaqueValue();
206 }
207 
208 // Teach SmallPtrSet that PointerUnion is "basically a pointer", that has
209 // # low bits available = min(PT1bits,PT2bits)-1.
210 template <typename PT1, typename PT2>
212  static inline void *getAsVoidPointer(const PointerUnion<PT1, PT2> &P) {
213  return P.getOpaqueValue();
214  }
215 
216  static inline PointerUnion<PT1, PT2> getFromVoidPointer(void *P) {
218  }
219 
220  // The number of bits available are the min of the two pointer types.
221  enum {
222  NumLowBitsAvailable = PointerLikeTypeTraits<
223  typename PointerUnion<PT1, PT2>::ValTy>::NumLowBitsAvailable
224  };
225 };
226 
229 template <typename PT1, typename PT2, typename PT3> class PointerUnion3 {
230 public:
233 
234 private:
235  ValTy Val;
236 
237  struct IsInnerUnion {
238  ValTy Val;
239 
240  IsInnerUnion(ValTy val) : Val(val) {}
241 
242  template <typename T> int is() const {
243  return Val.template is<InnerUnion>() &&
244  Val.template get<InnerUnion>().template is<T>();
245  }
246 
247  template <typename T> T get() const {
248  return Val.template get<InnerUnion>().template get<T>();
249  }
250  };
251 
252  struct IsPT3 {
253  ValTy Val;
254 
255  IsPT3(ValTy val) : Val(val) {}
256 
257  template <typename T> int is() const { return Val.template is<T>(); }
258  template <typename T> T get() const { return Val.template get<T>(); }
259  };
260 
261 public:
262  PointerUnion3() = default;
263  PointerUnion3(PT1 V) { Val = InnerUnion(V); }
264  PointerUnion3(PT2 V) { Val = InnerUnion(V); }
265  PointerUnion3(PT3 V) { Val = V; }
266 
269  bool isNull() const { return Val.isNull(); }
270  explicit operator bool() const { return !isNull(); }
271 
273  template <typename T> int is() const {
274  // If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3.
275  using Ty = typename ::wpi::PointerUnionTypeSelector<
276  PT1, T, IsInnerUnion,
278  return Ty(Val).template is<T>();
279  }
280 
284  template <typename T> T get() const {
285  assert(is<T>() && "Invalid accessor called");
286  // If T is PT1/PT2 choose IsInnerUnion otherwise choose IsPT3.
287  using Ty = typename ::wpi::PointerUnionTypeSelector<
288  PT1, T, IsInnerUnion,
290  return Ty(Val).template get<T>();
291  }
292 
295  template <typename T> T dyn_cast() const {
296  if (is<T>())
297  return get<T>();
298  return T();
299  }
300 
302  const PointerUnion3 &operator=(std::nullptr_t) {
303  Val = nullptr;
304  return *this;
305  }
306 
309  const PointerUnion3 &operator=(const PT1 &RHS) {
310  Val = InnerUnion(RHS);
311  return *this;
312  }
313  const PointerUnion3 &operator=(const PT2 &RHS) {
314  Val = InnerUnion(RHS);
315  return *this;
316  }
317  const PointerUnion3 &operator=(const PT3 &RHS) {
318  Val = RHS;
319  return *this;
320  }
321 
322  void *getOpaqueValue() const { return Val.getOpaqueValue(); }
323  static inline PointerUnion3 getFromOpaqueValue(void *VP) {
324  PointerUnion3 V;
325  V.Val = ValTy::getFromOpaqueValue(VP);
326  return V;
327  }
328 };
329 
330 // Teach SmallPtrSet that PointerUnion3 is "basically a pointer", that has
331 // # low bits available = min(PT1bits,PT2bits,PT2bits)-2.
332 template <typename PT1, typename PT2, typename PT3>
333 struct PointerLikeTypeTraits<PointerUnion3<PT1, PT2, PT3>> {
334  static inline void *getAsVoidPointer(const PointerUnion3<PT1, PT2, PT3> &P) {
335  return P.getOpaqueValue();
336  }
337 
338  static inline PointerUnion3<PT1, PT2, PT3> getFromVoidPointer(void *P) {
340  }
341 
342  // The number of bits available are the min of the two pointer types.
343  enum {
344  NumLowBitsAvailable = PointerLikeTypeTraits<
345  typename PointerUnion3<PT1, PT2, PT3>::ValTy>::NumLowBitsAvailable
346  };
347 };
348 
349 template <typename PT1, typename PT2, typename PT3>
350 bool operator<(PointerUnion3<PT1, PT2, PT3> lhs,
352  return lhs.getOpaqueValue() < rhs.getOpaqueValue();
353 }
354 
357 template <typename PT1, typename PT2, typename PT3, typename PT4>
359 public:
363 
364 private:
365  ValTy Val;
366 
367 public:
368  PointerUnion4() = default;
369  PointerUnion4(PT1 V) { Val = InnerUnion1(V); }
370  PointerUnion4(PT2 V) { Val = InnerUnion1(V); }
371  PointerUnion4(PT3 V) { Val = InnerUnion2(V); }
372  PointerUnion4(PT4 V) { Val = InnerUnion2(V); }
373 
376  bool isNull() const { return Val.isNull(); }
377  explicit operator bool() const { return !isNull(); }
378 
380  template <typename T> int is() const {
381  // If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2.
382  using Ty = typename ::wpi::PointerUnionTypeSelector<
383  PT1, T, InnerUnion1,
385  InnerUnion2>>::Return;
386  return Val.template is<Ty>() && Val.template get<Ty>().template is<T>();
387  }
388 
392  template <typename T> T get() const {
393  assert(is<T>() && "Invalid accessor called");
394  // If T is PT1/PT2 choose InnerUnion1 otherwise choose InnerUnion2.
395  using Ty = typename ::wpi::PointerUnionTypeSelector<
396  PT1, T, InnerUnion1,
398  InnerUnion2>>::Return;
399  return Val.template get<Ty>().template get<T>();
400  }
401 
404  template <typename T> T dyn_cast() const {
405  if (is<T>())
406  return get<T>();
407  return T();
408  }
409 
411  const PointerUnion4 &operator=(std::nullptr_t) {
412  Val = nullptr;
413  return *this;
414  }
415 
418  const PointerUnion4 &operator=(const PT1 &RHS) {
419  Val = InnerUnion1(RHS);
420  return *this;
421  }
422  const PointerUnion4 &operator=(const PT2 &RHS) {
423  Val = InnerUnion1(RHS);
424  return *this;
425  }
426  const PointerUnion4 &operator=(const PT3 &RHS) {
427  Val = InnerUnion2(RHS);
428  return *this;
429  }
430  const PointerUnion4 &operator=(const PT4 &RHS) {
431  Val = InnerUnion2(RHS);
432  return *this;
433  }
434 
435  void *getOpaqueValue() const { return Val.getOpaqueValue(); }
436  static inline PointerUnion4 getFromOpaqueValue(void *VP) {
437  PointerUnion4 V;
438  V.Val = ValTy::getFromOpaqueValue(VP);
439  return V;
440  }
441 };
442 
443 // Teach SmallPtrSet that PointerUnion4 is "basically a pointer", that has
444 // # low bits available = min(PT1bits,PT2bits,PT2bits)-2.
445 template <typename PT1, typename PT2, typename PT3, typename PT4>
446 struct PointerLikeTypeTraits<PointerUnion4<PT1, PT2, PT3, PT4>> {
447  static inline void *
448  getAsVoidPointer(const PointerUnion4<PT1, PT2, PT3, PT4> &P) {
449  return P.getOpaqueValue();
450  }
451 
452  static inline PointerUnion4<PT1, PT2, PT3, PT4> getFromVoidPointer(void *P) {
454  }
455 
456  // The number of bits available are the min of the two pointer types.
457  enum {
458  NumLowBitsAvailable = PointerLikeTypeTraits<
459  typename PointerUnion4<PT1, PT2, PT3, PT4>::ValTy>::NumLowBitsAvailable
460  };
461 };
462 
463 // Teach DenseMap how to use PointerUnions as keys.
464 template <typename T, typename U> struct DenseMapInfo<PointerUnion<T, U>> {
465  using Pair = PointerUnion<T, U>;
466  using FirstInfo = DenseMapInfo<T>;
467  using SecondInfo = DenseMapInfo<U>;
468 
469  static inline Pair getEmptyKey() { return Pair(FirstInfo::getEmptyKey()); }
470 
471  static inline Pair getTombstoneKey() {
472  return Pair(FirstInfo::getTombstoneKey());
473  }
474 
475  static unsigned getHashValue(const Pair &PairVal) {
476  intptr_t key = (intptr_t)PairVal.getOpaqueValue();
478  }
479 
480  static bool isEqual(const Pair &LHS, const Pair &RHS) {
481  return LHS.template is<T>() == RHS.template is<T>() &&
482  (LHS.template is<T>() ? FirstInfo::isEqual(LHS.template get<T>(),
483  RHS.template get<T>())
484  : SecondInfo::isEqual(LHS.template get<U>(),
485  RHS.template get<U>()));
486  }
487 };
488 
489 } // end namespace wpi
490 
491 #endif // WPIUTIL_WPI_POINTERUNION_H
wpi::PointerUnion::is
int is() const
Test if the Union currently holds the type matching T.
Definition: PointerUnion.h:123
wpi::PointerUnion4::isNull
bool isNull() const
Test if the pointer held in the union is null, regardless of which type it is.
Definition: PointerUnion.h:376
wpi::PointerUnion::operator=
const PointerUnion & operator=(const PT1 &RHS)
Assignment operators - Allow assigning into this union from either pointer type, setting the discrimi...
Definition: PointerUnion.h:173
wpi::PointerUnion::getAddrOfPtr1
PT1 * getAddrOfPtr1()
If the union is set to the first pointer type get an address pointing to it.
Definition: PointerUnion.h:156
wpi::PointerUnion3::isNull
bool isNull() const
Test if the pointer held in the union is null, regardless of which type it is.
Definition: PointerUnion.h:269
wpi::PointerUnion3::operator=
const PointerUnion3 & operator=(const PT1 &RHS)
Assignment operators - Allow assigning into this union from either pointer type, setting the discrimi...
Definition: PointerUnion.h:309
wpi::PointerUnion3::operator=
const PointerUnion3 & operator=(std::nullptr_t)
Assignment from nullptr which just clears the union.
Definition: PointerUnion.h:302
wpi::PointerUnionUIntTraits
Provide PointerLikeTypeTraits for void* that is used by PointerUnion for the two template arguments.
Definition: PointerUnion.h:59
wpi::PointerUnion4::operator=
const PointerUnion4 & operator=(const PT1 &RHS)
Assignment operators - Allow assigning into this union from either pointer type, setting the discrimi...
Definition: PointerUnion.h:418
wpi::PointerUnionTypeSelectorReturn
Definition: PointerUnion.h:27
wpi::PointerUnion3::is
int is() const
Test if the Union currently holds the type matching T.
Definition: PointerUnion.h:273
wpi::PointerUnion::operator=
const PointerUnion & operator=(std::nullptr_t)
Assignment from nullptr which just clears the union.
Definition: PointerUnion.h:166
wpi
WPILib C++ utilities (wpiutil) namespace.
Definition: EventLoopRunner.h:17
wpi::PointerUnionTypeSelector
Get a type based on whether two types are the same or not.
Definition: PointerUnion.h:41
wpi::PointerUnion::get
T get() const
Returns the value of the specified pointer type.
Definition: PointerUnion.h:135
wpi::PointerUnion3::get
T get() const
Returns the value of the specified pointer type.
Definition: PointerUnion.h:284
wpi::PointerUnion::isNull
bool isNull() const
Test if the pointer held in the union is null, regardless of which type it is.
Definition: PointerUnion.h:114
wpi::PointerUnion
A discriminated union of two pointer types, with the discriminator in the low bit of the pointer.
Definition: PointerUnion.h:87
wpi::PointerUnion::dyn_cast
T dyn_cast() const
Returns the current pointer if it is of the specified pointer type, otherwises returns null.
Definition: PointerUnion.h:142
wpi::PointerUnion4::dyn_cast
T dyn_cast() const
Returns the current pointer if it is of the specified pointer type, otherwises returns null.
Definition: PointerUnion.h:404
wpi::PointerUnion4::operator=
const PointerUnion4 & operator=(std::nullptr_t)
Assignment from nullptr which just clears the union.
Definition: PointerUnion.h:411
wpi::PointerUnion4
A pointer union of four pointer types.
Definition: PointerUnion.h:358
wpi::PointerLikeTypeTraits
A traits type that is used to handle pointer types and things that are just wrappers for pointers as ...
Definition: PointerLikeTypeTraits.h:26
wpi::PointerUnion4::is
int is() const
Test if the Union currently holds the type matching T.
Definition: PointerUnion.h:380
wpi::DenseMapInfo
Definition: DenseMapInfo.h:29
wpi::PointerUnion4::get
T get() const
Returns the value of the specified pointer type.
Definition: PointerUnion.h:392
wpi::PointerUnion3::dyn_cast
T dyn_cast() const
Returns the current pointer if it is of the specified pointer type, otherwises returns null.
Definition: PointerUnion.h:295
wpi::PointerIntPair< void *, 1, bool, PointerUnionUIntTraits< PT1, PT2 > >
wpi::PointerUnion::getAddrOfPtr1
const PT1 * getAddrOfPtr1() const
If the union is set to the first pointer type get an address pointing to it.
Definition: PointerUnion.h:150
wpi::PointerUnion3
A pointer union of three pointer types.
Definition: PointerUnion.h:229