FTL: Extend enum utilities imported from IF
Generalize compile-time and run-time lookup of enumerator names by
recognizing ftl_first and ftl_last to customize the range.
Add enum_range<E>() for iteration using range-based `for` loop.
Bug: 185536303
Test: Check assembly for small LUT in .rodata, and unrolled loops.
Test: ftl_test, libinput_tests, inputflinger_tests
Test: m libinputflinger
Change-Id: I0581611f4cfcf5837b0293867cb323742afb2c87
diff --git a/include/ftl/Flags.h b/include/ftl/Flags.h
index 27c8476..ae70831 100644
--- a/include/ftl/Flags.h
+++ b/include/ftl/Flags.h
@@ -1,5 +1,5 @@
/*
- * Copyright (C) 2020 The Android Open Source Project
+ * Copyright 2020 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@@ -14,79 +14,22 @@
* limitations under the License.
*/
-#include <android-base/stringprintf.h>
+#pragma once
-#include <array>
+#include <ftl/enum.h>
+#include <ftl/string.h>
+
#include <cstdint>
-#include <optional>
+#include <iterator>
#include <string>
#include <type_traits>
-#include <ftl/NamedEnum.h>
#include "utils/BitSet.h"
-#pragma once
+// TODO(b/185536303): Align with FTL style and namespace.
namespace android {
-namespace details {
-
-template <typename F>
-inline constexpr auto flag_count = sizeof(F) * __CHAR_BIT__;
-
-template <typename F, typename T, T... I>
-constexpr auto generate_flag_values(std::integer_sequence<T, I...> seq) {
- constexpr size_t count = seq.size();
-
- std::array<F, count> values{};
- for (size_t i = 0, v = 0; v < count; ++i) {
- values[v++] = static_cast<F>(T{1} << i);
- }
-
- return values;
-}
-
-template <typename F>
-inline constexpr auto flag_values = generate_flag_values<F>(
- std::make_integer_sequence<std::underlying_type_t<F>, flag_count<F>>{});
-
-template <typename F, std::size_t... I>
-constexpr auto generate_flag_names(std::index_sequence<I...>) noexcept {
- return std::array<std::optional<std::string_view>, sizeof...(I)>{
- {enum_value_name<F, flag_values<F>[I]>()...}};
-}
-
-template <typename F>
-inline constexpr auto flag_names =
- generate_flag_names<F>(std::make_index_sequence<flag_count<F>>{});
-
-// A trait for determining whether a type is specifically an enum class or not.
-template <typename T, bool = std::is_enum_v<T>>
-struct is_enum_class : std::false_type {};
-
-// By definition, an enum class is an enum that is not implicitly convertible to its underlying
-// type.
-template <typename T>
-struct is_enum_class<T, true>
- : std::bool_constant<!std::is_convertible_v<T, std::underlying_type_t<T>>> {};
-
-template <typename T>
-inline constexpr bool is_enum_class_v = is_enum_class<T>::value;
-} // namespace details
-
-template <auto V>
-constexpr auto flag_name() {
- using F = decltype(V);
- return details::enum_value_name<F, V>();
-}
-
-template <typename F>
-constexpr std::optional<std::string_view> flag_name(F flag) {
- using U = std::underlying_type_t<F>;
- auto idx = static_cast<size_t>(__builtin_ctzl(static_cast<U>(flag)));
- return details::flag_names<F>[idx];
-}
-
/* A class for handling flags defined by an enum or enum class in a type-safe way. */
template <typename F>
class Flags {
@@ -94,7 +37,7 @@
// further to avoid this restriction but in general we want to encourage the use of enums
// anyways.
static_assert(std::is_enum_v<F>, "Flags type must be an enum");
- using U = typename std::underlying_type_t<F>;
+ using U = std::underlying_type_t<F>;
public:
constexpr Flags(F f) : mFlags(static_cast<U>(f)) {}
@@ -106,11 +49,10 @@
// 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<!details::is_enum_class_v<F>, T>* = nullptr)
- : mFlags(t) {}
+ constexpr Flags(T t, std::enable_if_t<!ftl::is_scoped_enum_v<F>, T>* = nullptr) : mFlags(t) {}
+
template <typename T = U>
- explicit constexpr Flags(T t,
- typename std::enable_if_t<details::is_enum_class_v<F>, T>* = nullptr)
+ explicit constexpr Flags(T t, std::enable_if_t<ftl::is_scoped_enum_v<F>, T>* = nullptr)
: mFlags(t) {}
class Iterator {
@@ -229,16 +171,16 @@
bool first = true;
U unstringified = 0;
for (const F f : *this) {
- std::optional<std::string_view> flagString = flag_name(f);
- if (flagString) {
- appendFlag(result, flagString.value(), first);
+ if (const auto flagName = ftl::flag_name(f)) {
+ appendFlag(result, flagName.value(), first);
} else {
unstringified |= static_cast<U>(f);
}
}
if (unstringified != 0) {
- appendFlag(result, base::StringPrintf("0x%08x", unstringified), first);
+ constexpr auto radix = sizeof(U) == 1 ? ftl::Radix::kBin : ftl::Radix::kHex;
+ appendFlag(result, ftl::to_string(unstringified, radix), first);
}
if (first) {
@@ -265,15 +207,14 @@
// as flags. In order to use these, add them via a `using namespace` declaration.
namespace flag_operators {
-template <typename F, typename = std::enable_if_t<details::is_enum_class_v<F>>>
+template <typename F, typename = std::enable_if_t<ftl::is_scoped_enum_v<F>>>
inline Flags<F> operator~(F f) {
- using U = typename std::underlying_type_t<F>;
- return static_cast<F>(~static_cast<U>(f));
+ return static_cast<F>(~ftl::enum_cast(f));
}
-template <typename F, typename = std::enable_if_t<details::is_enum_class_v<F>>>
+
+template <typename F, typename = std::enable_if_t<ftl::is_scoped_enum_v<F>>>
Flags<F> operator|(F lhs, F rhs) {
- using U = typename std::underlying_type_t<F>;
- return static_cast<F>(static_cast<U>(lhs) | static_cast<U>(rhs));
+ return static_cast<F>(ftl::enum_cast(lhs) | ftl::enum_cast(rhs));
}
} // namespace flag_operators
diff --git a/include/ftl/NamedEnum.h b/include/ftl/NamedEnum.h
deleted file mode 100644
index 6e98fee..0000000
--- a/include/ftl/NamedEnum.h
+++ /dev/null
@@ -1,129 +0,0 @@
-/*
- * Copyright (C) 2020 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- * http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <android-base/stringprintf.h>
-
-#include <array>
-#include <cstdint>
-#include <optional>
-#include <string>
-
-#pragma once
-
-namespace android {
-
-namespace details {
-template <typename E, E V>
-constexpr std::optional<std::string_view> enum_value_name() {
- // Should look something like (but all on one line):
- // std::optional<std::string_view>
- // android::details::enum_value_name()
- // [E = android::test::TestEnums, V = android::test::TestEnums::ONE]
- std::string_view view = __PRETTY_FUNCTION__;
- size_t templateStart = view.rfind("[");
- size_t templateEnd = view.rfind("]");
- if (templateStart == std::string::npos || templateEnd == std::string::npos) {
- return std::nullopt;
- }
-
- // Extract the template parameters without the enclosing braces.
- // Example (cont'd): E = android::test::TestEnums, V = android::test::TestEnums::ONE
- view = view.substr(templateStart + 1, templateEnd - templateStart - 1);
- size_t valStart = view.rfind("V = ");
- if (valStart == std::string::npos) {
- return std::nullopt;
- }
-
- // Example (cont'd): V = android::test::TestEnums::ONE
- view = view.substr(valStart);
- // Check invalid enum values with cast, like V = (android::test::TestEnums)8.
- if (view.find('(') != std::string::npos) {
- return std::nullopt;
- }
- size_t nameStart = view.rfind("::");
- if (nameStart == std::string::npos) {
- return std::nullopt;
- }
-
- // Chop off the initial "::"
- nameStart += 2;
- return view.substr(nameStart);
-}
-
-template <typename E, typename T, T... I>
-constexpr auto generate_enum_values(std::integer_sequence<T, I...> seq) {
- constexpr size_t count = seq.size();
-
- std::array<E, count> values{};
- for (size_t i = 0, v = 0; v < count; ++i) {
- values[v++] = static_cast<E>(T{0} + i);
- }
-
- return values;
-}
-
-template <typename E, std::size_t N>
-inline constexpr auto enum_values =
- generate_enum_values<E>(std::make_integer_sequence<std::underlying_type_t<E>, N>{});
-
-template <typename E, std::size_t N, std::size_t... I>
-constexpr auto generate_enum_names(std::index_sequence<I...>) noexcept {
- return std::array<std::optional<std::string_view>, sizeof...(I)>{
- {enum_value_name<E, enum_values<E, N>[I]>()...}};
-}
-
-template <typename E, std::size_t N>
-inline constexpr auto enum_names = generate_enum_names<E, N>(std::make_index_sequence<N>{});
-
-} // namespace details
-
-class NamedEnum {
-public:
- // By default allowed enum value range is 0 ~ 7.
- template <typename E>
- static constexpr size_t max = 8;
-
- template <auto V>
- static constexpr auto enum_name() {
- using E = decltype(V);
- return details::enum_value_name<E, V>();
- }
-
- template <typename E>
- static constexpr std::optional<std::string_view> enum_name(E val) {
- auto idx = static_cast<size_t>(val);
- return idx < max<E> ? details::enum_names<E, max<E>>[idx] : std::nullopt;
- }
-
- // Helper function for parsing enum value to string.
- // Example : enum class TestEnums { ZERO = 0x0 };
- // NamedEnum::string(TestEnums::ZERO) returns string of "ZERO".
- // Note the default maximum enum is 8, if the enum ID to be parsed if greater than 8 like 16,
- // it should be declared to specialized the maximum enum by below:
- // template <> constexpr size_t NamedEnum::max<TestEnums> = 16;
- // If the enum class definition is sparse and contains enum values starting from a large value,
- // Do not specialize it to a large number to avoid performance issues.
- // The recommended maximum enum number to specialize is 64.
- template <typename E>
- static const std::string string(E val, const char* fallbackFormat = "%02d") {
- std::string result;
- std::optional<std::string_view> enumString = enum_name(val);
- result += enumString ? enumString.value() : base::StringPrintf(fallbackFormat, val);
- return result;
- }
-};
-
-} // namespace android
diff --git a/include/ftl/enum.h b/include/ftl/enum.h
new file mode 100644
index 0000000..dfe3a09
--- /dev/null
+++ b/include/ftl/enum.h
@@ -0,0 +1,299 @@
+/*
+ * Copyright 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+#include <cstddef>
+#include <limits>
+#include <optional>
+#include <string_view>
+#include <type_traits>
+#include <utility>
+
+#include <ftl/string.h>
+
+// Returns the name of enumerator E::V (i.e. "V") as std::optional<std::string_view> by parsing the
+// compiler-generated string literal for the signature of this function. The function is defined in
+// the global namespace with a short name and inferred return type to reduce bloat in the read-only
+// data segment.
+template <typename E, E V>
+constexpr auto ftl_enum() {
+ static_assert(std::is_enum_v<E>);
+
+ using R = std::optional<std::string_view>;
+ using namespace std::literals;
+
+ // The "pretty" signature has the following format:
+ //
+ // auto ftl_enum() [E = android::test::Enum, V = android::test::Enum::kValue]
+ //
+ std::string_view view = __PRETTY_FUNCTION__;
+ const auto template_begin = view.rfind('[');
+ const auto template_end = view.rfind(']');
+ if (template_begin == view.npos || template_end == view.npos) return R{};
+
+ // Extract the template parameters without the enclosing brackets. Example (cont'd):
+ //
+ // E = android::test::Enum, V = android::test::Enum::kValue
+ //
+ view = view.substr(template_begin + 1, template_end - template_begin - 1);
+ const auto value_begin = view.rfind("V = "sv);
+ if (value_begin == view.npos) return R{};
+
+ // Example (cont'd):
+ //
+ // V = android::test::Enum::kValue
+ //
+ view = view.substr(value_begin);
+ const auto name_begin = view.rfind("::"sv);
+ if (name_begin == view.npos) return R{};
+
+ // Chop off the leading "::".
+ const auto name = view.substr(name_begin + 2);
+
+ // A value that is not enumerated has the format "Enum)42".
+ return name.find(')') == view.npos ? R{name} : R{};
+}
+
+namespace android::ftl {
+
+// Trait for determining whether a type is specifically a scoped enum or not. By definition, a
+// scoped enum is one that is not implicitly convertible to its underlying type.
+//
+// TODO: Replace with std::is_scoped_enum in C++23.
+//
+template <typename T, bool = std::is_enum_v<T>>
+struct is_scoped_enum : std::false_type {};
+
+template <typename T>
+struct is_scoped_enum<T, true> : std::negation<std::is_convertible<T, std::underlying_type_t<T>>> {
+};
+
+template <typename T>
+inline constexpr bool is_scoped_enum_v = is_scoped_enum<T>::value;
+
+// Shorthand for casting an enumerator to its integral value.
+//
+// enum class E { A, B, C };
+// static_assert(ftl::enum_cast(E::B) == 1);
+//
+template <typename E>
+constexpr auto enum_cast(E v) {
+ return static_cast<std::underlying_type_t<E>>(v);
+}
+
+// Traits for retrieving an enum's range. An enum specifies its range by defining enumerators named
+// ftl_first and ftl_last. If omitted, ftl_first defaults to 0, whereas ftl_last defaults to N - 1
+// where N is the bit width of the underlying type, but only if that type is unsigned, assuming the
+// enumerators are flags. Also, note that unscoped enums must define both bounds, as casting out-of-
+// range values results in undefined behavior if the underlying type is not fixed.
+//
+// enum class E { A, B, C, F = 5, ftl_last = F };
+//
+// static_assert(ftl::enum_begin_v<E> == E::A);
+// static_assert(ftl::enum_last_v<E> == E::F);
+// static_assert(ftl::enum_size_v<E> == 6);
+//
+// enum class F : std::uint16_t { X = 0b1, Y = 0b10, Z = 0b100 };
+//
+// static_assert(ftl::enum_begin_v<F> == F{0});
+// static_assert(ftl::enum_last_v<F> == F{15});
+// static_assert(ftl::enum_size_v<F> == 16);
+//
+template <typename E, typename = void>
+struct enum_begin {
+ static_assert(is_scoped_enum_v<E>, "Missing ftl_first enumerator");
+ static constexpr E value{0};
+};
+
+template <typename E>
+struct enum_begin<E, std::void_t<decltype(E::ftl_first)>> {
+ static constexpr E value = E::ftl_first;
+};
+
+template <typename E>
+inline constexpr E enum_begin_v = enum_begin<E>::value;
+
+template <typename E, typename = void>
+struct enum_end {
+ using U = std::underlying_type_t<E>;
+ static_assert(is_scoped_enum_v<E> && std::is_unsigned_v<U>, "Missing ftl_last enumerator");
+
+ static constexpr E value{std::numeric_limits<U>::digits};
+};
+
+template <typename E>
+struct enum_end<E, std::void_t<decltype(E::ftl_last)>> {
+ static constexpr E value = E{enum_cast(E::ftl_last) + 1};
+};
+
+template <typename E>
+inline constexpr E enum_end_v = enum_end<E>::value;
+
+template <typename E>
+inline constexpr E enum_last_v = E{enum_cast(enum_end_v<E>) - 1};
+
+template <typename E>
+struct enum_size {
+ static constexpr auto kBegin = enum_cast(enum_begin_v<E>);
+ static constexpr auto kEnd = enum_cast(enum_end_v<E>);
+ static_assert(kBegin < kEnd, "Invalid range");
+
+ static constexpr std::size_t value = kEnd - kBegin;
+ static_assert(value <= 64, "Excessive range size");
+};
+
+template <typename E>
+inline constexpr std::size_t enum_size_v = enum_size<E>::value;
+
+namespace details {
+
+template <auto V>
+struct Identity {
+ static constexpr auto value = V;
+};
+
+template <typename E>
+using make_enum_sequence = std::make_integer_sequence<std::underlying_type_t<E>, enum_size_v<E>>;
+
+template <typename E, template <E> class = Identity, typename = make_enum_sequence<E>>
+struct EnumRange;
+
+template <typename E, template <E> class F, typename T, T... Vs>
+struct EnumRange<E, F, std::integer_sequence<T, Vs...>> {
+ static constexpr auto kBegin = enum_cast(enum_begin_v<E>);
+ static constexpr auto kSize = enum_size_v<E>;
+
+ using R = decltype(F<E{}>::value);
+ const R values[kSize] = {F<static_cast<E>(Vs + kBegin)>::value...};
+
+ constexpr const auto* begin() const { return values; }
+ constexpr const auto* end() const { return values + kSize; }
+};
+
+template <auto V>
+struct EnumName {
+ static constexpr auto value = ftl_enum<decltype(V), V>();
+};
+
+template <auto I>
+struct FlagName {
+ using E = decltype(I);
+ using U = std::underlying_type_t<E>;
+
+ static constexpr E V{U{1} << enum_cast(I)};
+ static constexpr auto value = ftl_enum<E, V>();
+};
+
+} // namespace details
+
+// Returns an iterable over the range of an enum.
+//
+// enum class E { A, B, C, F = 5, ftl_last = F };
+//
+// std::string string;
+// for (E v : ftl::enum_range<E>()) {
+// string += ftl::enum_name(v).value_or("?");
+// }
+//
+// assert(string == "ABC??F");
+//
+template <typename E>
+constexpr auto enum_range() {
+ return details::EnumRange<E>{};
+}
+
+// Returns a stringified enumerator at compile time.
+//
+// enum class E { A, B, C };
+// static_assert(ftl::enum_name<E::B>() == "B");
+//
+template <auto V>
+constexpr std::string_view enum_name() {
+ constexpr auto kName = ftl_enum<decltype(V), V>();
+ static_assert(kName, "Unknown enumerator");
+ return *kName;
+}
+
+// Returns a stringified enumerator, possibly at compile time.
+//
+// enum class E { A, B, C, F = 5, ftl_last = F };
+//
+// static_assert(ftl::enum_name(E::C).value_or("?") == "C");
+// static_assert(ftl::enum_name(E{3}).value_or("?") == "?");
+//
+template <typename E>
+constexpr std::optional<std::string_view> enum_name(E v) {
+ const auto value = enum_cast(v);
+
+ constexpr auto kBegin = enum_cast(enum_begin_v<E>);
+ constexpr auto kLast = enum_cast(enum_last_v<E>);
+ if (value < kBegin || value > kLast) return {};
+
+ constexpr auto kRange = details::EnumRange<E, details::EnumName>{};
+ return kRange.values[value - kBegin];
+}
+
+// Returns a stringified flag enumerator, possibly at compile time.
+//
+// enum class F : std::uint16_t { X = 0b1, Y = 0b10, Z = 0b100 };
+//
+// static_assert(ftl::flag_name(F::Z).value_or("?") == "Z");
+// static_assert(ftl::flag_name(F{0b111}).value_or("?") == "?");
+//
+template <typename E>
+constexpr std::optional<std::string_view> flag_name(E v) {
+ const auto value = enum_cast(v);
+
+ // TODO: Replace with std::popcount and std::countr_zero in C++20.
+ if (__builtin_popcountl(value) != 1) return {};
+
+ constexpr auto kRange = details::EnumRange<E, details::FlagName>{};
+ return kRange.values[__builtin_ctzl(value)];
+}
+
+// Returns a stringified enumerator, or its integral value if not named.
+//
+// enum class E { A, B, C, F = 5, ftl_last = F };
+//
+// assert(ftl::enum_string(E::C) == "C");
+// assert(ftl::enum_string(E{3}) == "3");
+//
+template <typename E>
+inline std::string enum_string(E v) {
+ if (const auto name = enum_name(v)) {
+ return std::string(*name);
+ }
+ return to_string(enum_cast(v));
+}
+
+// Returns a stringified flag enumerator, or its integral value if not named.
+//
+// enum class F : std::uint16_t { X = 0b1, Y = 0b10, Z = 0b100 };
+//
+// assert(ftl::flag_string(F::Z) == "Z");
+// assert(ftl::flag_string(F{7}) == "0b111");
+//
+template <typename E>
+inline std::string flag_string(E v) {
+ if (const auto name = flag_name(v)) {
+ return std::string(*name);
+ }
+ constexpr auto radix = sizeof(E) == 1 ? Radix::kBin : Radix::kHex;
+ return to_string(enum_cast(v), radix);
+}
+
+} // namespace android::ftl
diff --git a/include/input/DisplayViewport.h b/include/input/DisplayViewport.h
index a6213f3..9148fee 100644
--- a/include/input/DisplayViewport.h
+++ b/include/input/DisplayViewport.h
@@ -18,7 +18,8 @@
#define _LIBINPUT_DISPLAY_VIEWPORT_H
#include <android-base/stringprintf.h>
-#include <ftl/NamedEnum.h>
+#include <ftl/enum.h>
+#include <ftl/string.h>
#include <gui/constants.h>
#include <input/Input.h>
@@ -44,6 +45,8 @@
INTERNAL = 1,
EXTERNAL = 2,
VIRTUAL = 3,
+
+ ftl_last = VIRTUAL
};
/*
@@ -132,9 +135,8 @@
"physicalFrame=[%d, %d, %d, %d], "
"deviceSize=[%d, %d], "
"isActive=[%d]",
- NamedEnum::string(type).c_str(), displayId, uniqueId.c_str(),
- physicalPort ? StringPrintf("%" PRIu8, *physicalPort).c_str()
- : "<none>",
+ ftl::enum_string(type).c_str(), displayId, uniqueId.c_str(),
+ physicalPort ? ftl::to_string(*physicalPort).c_str() : "<none>",
orientation, logicalLeft, logicalTop, logicalRight, logicalBottom,
physicalLeft, physicalTop, physicalRight, physicalBottom, deviceWidth,
deviceHeight, isActive);
diff --git a/include/input/InputDevice.h b/include/input/InputDevice.h
index 7f0324a..22aae19 100644
--- a/include/input/InputDevice.h
+++ b/include/input/InputDevice.h
@@ -84,6 +84,9 @@
GAME_ROTATION_VECTOR = ASENSOR_TYPE_GAME_ROTATION_VECTOR,
GYROSCOPE_UNCALIBRATED = ASENSOR_TYPE_GYROSCOPE_UNCALIBRATED,
SIGNIFICANT_MOTION = ASENSOR_TYPE_SIGNIFICANT_MOTION,
+
+ ftl_first = ACCELEROMETER,
+ ftl_last = SIGNIFICANT_MOTION
};
enum class InputDeviceSensorAccuracy : int32_t {
@@ -105,6 +108,8 @@
PLAYER_ID = 1,
RGB = 2,
MULTI_COLOR = 3,
+
+ ftl_last = MULTI_COLOR
};
struct InputDeviceSensorInfo {
diff --git a/include/input/InputTransport.h b/include/input/InputTransport.h
index 9a150eb..7632b30 100644
--- a/include/input/InputTransport.h
+++ b/include/input/InputTransport.h
@@ -73,6 +73,8 @@
DRAG,
TIMELINE,
TOUCH_MODE,
+
+ ftl_last = TOUCH_MODE
};
struct Header {