Add Flags<F>::Iterator.
This simplifies the string code and seems generally useful for people
that want to operate on individual flags.
Bug: 160010896
Test: atest libinput_tests
Change-Id: I13aa913eb85d6294b2bf3c899a6a1ab700a40374
diff --git a/include/input/Flags.h b/include/input/Flags.h
index f3198c9..0f52e18 100644
--- a/include/input/Flags.h
+++ b/include/input/Flags.h
@@ -50,61 +50,123 @@
using U = typename std::underlying_type_t<F>;
public:
- constexpr Flags(F f) : flags(static_cast<U>(f)) {}
- constexpr Flags() : flags(0) {}
- constexpr Flags(const Flags<F>& f) : flags(f.flags) {}
+ constexpr Flags(F f) : mFlags(static_cast<U>(f)) {}
+ constexpr Flags() : mFlags(0) {}
+ constexpr Flags(const Flags<F>& f) : mFlags(f.mFlags) {}
// Provide a non-explicit construct for non-enum classes since they easily convert to their
// underlying types (e.g. when used with bitwise operators). For enum classes, however, we
// should force them to be explicitly constructed from their underlying types to make full use
// of the type checker.
template <typename T = U>
- constexpr Flags(T t, typename std::enable_if_t<!is_enum_class_v<F>, T>* = nullptr) : flags(t) {}
+ constexpr Flags(T t, typename std::enable_if_t<!is_enum_class_v<F>, T>* = nullptr)
+ : mFlags(t) {}
template <typename T = U>
explicit constexpr Flags(T t, typename std::enable_if_t<is_enum_class_v<F>, T>* = nullptr)
- : flags(t) {}
+ : mFlags(t) {}
+
+ class Iterator {
+ // The type can't be larger than 64-bits otherwise it won't fit in BitSet64.
+ static_assert(sizeof(U) <= sizeof(uint64_t));
+
+ public:
+ Iterator(Flags<F> flags) : mRemainingFlags(flags.mFlags) { (*this)++; }
+ Iterator() : mRemainingFlags(0), mCurrFlag(static_cast<F>(0)) {}
+
+ // Pre-fix ++
+ Iterator& operator++() {
+ if (mRemainingFlags.isEmpty()) {
+ mCurrFlag = static_cast<F>(0);
+ } else {
+ uint64_t bit = mRemainingFlags.clearLastMarkedBit(); // counts from left
+ const U flag = 1 << (64 - bit - 1);
+ mCurrFlag = static_cast<F>(flag);
+ }
+ return *this;
+ }
+
+ // Post-fix ++
+ Iterator operator++(int) {
+ Iterator iter = *this;
+ ++*this;
+ return iter;
+ }
+
+ bool operator==(Iterator other) const {
+ return mCurrFlag == other.mCurrFlag && mRemainingFlags == other.mRemainingFlags;
+ }
+
+ bool operator!=(Iterator other) const { return !(*this == other); }
+
+ F operator*() { return mCurrFlag; }
+
+ // iterator traits
+
+ // In the future we could make this a bidirectional const iterator instead of a forward
+ // iterator but it doesn't seem worth the added complexity at this point. This could not,
+ // however, be made a non-const iterator as assigning one flag to another is a non-sensical
+ // operation.
+ using iterator_category = std::input_iterator_tag;
+ using value_type = F;
+ // Per the C++ spec, because input iterators are not assignable the iterator's reference
+ // type does not actually need to be a reference. In fact, making it a reference would imply
+ // that modifying it would change the underlying Flags object, which is obviously wrong for
+ // the same reason this can't be a non-const iterator.
+ using reference = F;
+ using difference_type = void;
+ using pointer = void;
+
+ private:
+ BitSet64 mRemainingFlags;
+ F mCurrFlag;
+ };
+
/*
* Tests whether the given flag is set.
*/
bool test(F flag) const {
U f = static_cast<U>(flag);
- return (f & flags) == f;
+ return (f & mFlags) == f;
}
/* Tests whether any of the given flags are set */
- bool any(Flags<F> f) { return (flags & f.flags) != 0; }
+ bool any(Flags<F> f) { return (mFlags & f.mFlags) != 0; }
/* Tests whether all of the given flags are set */
- bool all(Flags<F> f) { return (flags & f.flags) == f.flags; }
+ bool all(Flags<F> f) { return (mFlags & f.mFlags) == f.mFlags; }
- Flags<F> operator|(Flags<F> rhs) const { return static_cast<F>(flags | rhs.flags); }
+ Flags<F> operator|(Flags<F> rhs) const { return static_cast<F>(mFlags | rhs.mFlags); }
Flags<F>& operator|=(Flags<F> rhs) {
- flags = flags | rhs.flags;
+ mFlags = mFlags | rhs.mFlags;
return *this;
}
- Flags<F> operator&(Flags<F> rhs) const { return static_cast<F>(flags & rhs.flags); }
+ Flags<F> operator&(Flags<F> rhs) const { return static_cast<F>(mFlags & rhs.mFlags); }
Flags<F>& operator&=(Flags<F> rhs) {
- flags = flags & rhs.flags;
+ mFlags = mFlags & rhs.mFlags;
return *this;
}
- Flags<F> operator^(Flags<F> rhs) const { return static_cast<F>(flags ^ rhs.flags); }
+ Flags<F> operator^(Flags<F> rhs) const { return static_cast<F>(mFlags ^ rhs.mFlags); }
Flags<F>& operator^=(Flags<F> rhs) {
- flags = flags ^ rhs.flags;
+ mFlags = mFlags ^ rhs.mFlags;
return *this;
}
- Flags<F> operator~() { return static_cast<F>(~flags); }
+ Flags<F> operator~() { return static_cast<F>(~mFlags); }
- bool operator==(Flags<F> rhs) const { return flags == rhs.flags; }
+ bool operator==(Flags<F> rhs) const { return mFlags == rhs.mFlags; }
bool operator!=(Flags<F> rhs) const { return !operator==(rhs); }
Flags<F>& operator=(const Flags<F>& rhs) {
- flags = rhs.flags;
+ mFlags = rhs.mFlags;
return *this;
}
+ Iterator begin() const { return Iterator(*this); }
+
+ Iterator end() const { return Iterator(); }
+
/*
* Returns the stored set of flags.
*
@@ -112,24 +174,20 @@
* the value is no longer necessarily a strict member of the enum since the returned value could
* be multiple enum variants OR'd together.
*/
- U get() const { return flags; }
+ U get() const { return mFlags; }
std::string string() const { return string(defaultStringify); }
std::string string(std::function<std::optional<std::string>(F)> stringify) const {
- // The type can't be larger than 64-bits otherwise it won't fit in BitSet64.
- static_assert(sizeof(U) <= sizeof(uint64_t));
std::string result;
bool first = true;
U unstringified = 0;
- for (BitSet64 bits(flags); !bits.isEmpty();) {
- uint64_t bit = bits.clearLastMarkedBit(); // counts from left
- const U flag = 1 << (64 - bit - 1);
- std::optional<std::string> flagString = stringify(static_cast<F>(flag));
+ for (const F f : *this) {
+ std::optional<std::string> flagString = stringify(f);
if (flagString) {
appendFlag(result, flagString.value(), first);
} else {
- unstringified |= flag;
+ unstringified |= static_cast<U>(f);
}
}
@@ -145,7 +203,7 @@
}
private:
- U flags;
+ U mFlags;
static std::optional<std::string> defaultStringify(F) { return std::nullopt; }
static void appendFlag(std::string& str, const std::string& flag, bool& first) {