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-rw-r--r--src/common/bit_field.h28
1 files changed, 16 insertions, 12 deletions
diff --git a/src/common/bit_field.h b/src/common/bit_field.h
index 21e07925d..902e668e3 100644
--- a/src/common/bit_field.h
+++ b/src/common/bit_field.h
@@ -34,6 +34,7 @@
34#include <limits> 34#include <limits>
35#include <type_traits> 35#include <type_traits>
36#include "common/common_funcs.h" 36#include "common/common_funcs.h"
37#include "common/swap.h"
37 38
38/* 39/*
39 * Abstract bitfield class 40 * Abstract bitfield class
@@ -108,15 +109,9 @@
108 * symptoms. 109 * symptoms.
109 */ 110 */
110#pragma pack(1) 111#pragma pack(1)
111template <std::size_t Position, std::size_t Bits, typename T> 112template <std::size_t Position, std::size_t Bits, typename T, typename EndianTag = LETag>
112struct BitField { 113struct BitField {
113private: 114private:
114 // We hide the copy assigment operator here, because the default copy
115 // assignment would copy the full storage value, rather than just the bits
116 // relevant to this particular bit field.
117 // We don't delete it because we want BitField to be trivially copyable.
118 constexpr BitField& operator=(const BitField&) = default;
119
120 // UnderlyingType is T for non-enum types and the underlying type of T if 115 // UnderlyingType is T for non-enum types and the underlying type of T if
121 // T is an enumeration. Note that T is wrapped within an enable_if in the 116 // T is an enumeration. Note that T is wrapped within an enable_if in the
122 // former case to workaround compile errors which arise when using 117 // former case to workaround compile errors which arise when using
@@ -127,6 +122,8 @@ private:
127 // We store the value as the unsigned type to avoid undefined behaviour on value shifting 122 // We store the value as the unsigned type to avoid undefined behaviour on value shifting
128 using StorageType = std::make_unsigned_t<UnderlyingType>; 123 using StorageType = std::make_unsigned_t<UnderlyingType>;
129 124
125 using StorageTypeWithEndian = typename AddEndian<StorageType, EndianTag>::type;
126
130public: 127public:
131 /// Constants to allow limited introspection of fields if needed 128 /// Constants to allow limited introspection of fields if needed
132 static constexpr std::size_t position = Position; 129 static constexpr std::size_t position = Position;
@@ -163,16 +160,20 @@ public:
163 BitField(T val) = delete; 160 BitField(T val) = delete;
164 BitField& operator=(T val) = delete; 161 BitField& operator=(T val) = delete;
165 162
166 // Force default constructor to be created 163 constexpr BitField() noexcept = default;
167 // so that we can use this within unions 164
168 constexpr BitField() = default; 165 constexpr BitField(const BitField&) noexcept = default;
166 constexpr BitField& operator=(const BitField&) noexcept = default;
167
168 constexpr BitField(BitField&&) noexcept = default;
169 constexpr BitField& operator=(BitField&&) noexcept = default;
169 170
170 constexpr FORCE_INLINE operator T() const { 171 constexpr FORCE_INLINE operator T() const {
171 return Value(); 172 return Value();
172 } 173 }
173 174
174 constexpr FORCE_INLINE void Assign(const T& value) { 175 constexpr FORCE_INLINE void Assign(const T& value) {
175 storage = (storage & ~mask) | FormatValue(value); 176 storage = (static_cast<StorageType>(storage) & ~mask) | FormatValue(value);
176 } 177 }
177 178
178 constexpr T Value() const { 179 constexpr T Value() const {
@@ -184,7 +185,7 @@ public:
184 } 185 }
185 186
186private: 187private:
187 StorageType storage; 188 StorageTypeWithEndian storage;
188 189
189 static_assert(bits + position <= 8 * sizeof(T), "Bitfield out of range"); 190 static_assert(bits + position <= 8 * sizeof(T), "Bitfield out of range");
190 191
@@ -195,3 +196,6 @@ private:
195 static_assert(std::is_trivially_copyable_v<T>, "T must be trivially copyable in a BitField"); 196 static_assert(std::is_trivially_copyable_v<T>, "T must be trivially copyable in a BitField");
196}; 197};
197#pragma pack() 198#pragma pack()
199
200template <std::size_t Position, std::size_t Bits, typename T>
201using BitFieldBE = BitField<Position, Bits, T, BETag>;