edm4hep/utils/bit_utils.h

0001 #ifndef EDM4HEP_UTILS_BIT_UTILS_HH
0002 #define EDM4HEP_UTILS_BIT_UTILS_HH
0003
0004 #include <type_traits>
0005
0006 namespace edm4hep::utils {
0007
0008 /// Set a bit in the passed bitfield to the desired value
0009 ///
0010 /// @tparam T any integer type that can be used as a bitfield, typically an
0011 ///           unsigned integer type
0012 ///
0013 /// @param bitfield The bitfield for which the bit should be set
0014 /// @param bit      The bit (number) that should be set
0015 /// @param value    The value to which the bit should be set
0016 ///
0017 /// @returns The new value of the bitfield after setting bits
0018 template <typename T>
0019 constexpr T setBit(T bitfield, int bit, bool value) {
0020   return (bitfield & ~(0x1 << bit)) | (value << bit);
0021 }
0022
0023 /// Set multiple bits to one desired value in the passed bitfield
0024 ///
0025 /// @tparam T any integer type that can be used as a bitfield, typically an
0026 ///           unsigned integer type
0027 /// @tparam Bits A variable number of bits (numbers) that should be set
0028 ///
0029 /// @param bitfield The bitfield for which the bit should be set
0030 /// @param value    The value to which the bit should be set
0031 /// @param bits     The bits that should be set
0032 template <typename T, typename... Bits>
0033 constexpr T setBits(T bitfield, bool value, Bits... bits) {
0034   static_assert((std::is_same_v<Bits, int> && ...), "All bit numbers to set must be integers");
0035   static_assert(sizeof...(bits) > 0, "Need at least one bit to set");
0036
0037   for (auto n : {bits...}) {
0038     bitfield = setBit(bitfield, n, value);
0039   }
0040   return bitfield;
0041 }
0042
0043 /// Check if a bit is set in the bitfield
0044 ///
0045 /// @tparam T any integer type that can be used as a bitfield, typically an
0046 ///           unsigned integer type
0047 ///
0048 /// @param bitfield The bitfield that should be checked
0049 /// @param bit      The bit (number) that should be checked
0050 ///
0051 /// @returns true if the passed bit is set in the bitfield and false otherwise
0052 template <typename T>
0053 constexpr bool checkBit(T bitfield, int bit) {
0054   return bitfield & (0x1 << bit);
0055 }
0056
0057 /// Check if all the passed bits are set in the bitfield
0058 ///
0059 /// @tparam T any integer type that can be used as a bitfield, typically an
0060 ///           unsigned integer type
0061 /// @tparam Bits A variable number of bits (numbers) that should be checked
0062 ///
0063 /// @param bitfield The bitfield that should be checked
0064 /// @param bits     The bits that should be checked
0065 ///
0066 /// @returns true if all the passed bits are set in the bitfield and false
0067 ///          otherwise
0068 template <typename T, typename... Bits>
0069 constexpr bool checkAllBits(T bitfield, Bits... bits) {
0070   static_assert((std::is_same_v<Bits, int> && ...), "All bit numbers to set must be integers");
0071   static_assert(sizeof...(bits) > 0, "Need at least one bit to check");
0072   return (true && ... && checkBit(bitfield, bits));
0073 }
0074
0075 /// Check if any of the passed bits is set in the bitfield
0076 ///
0077 /// @tparam T any integer type that can be used as a bitfield, typically an
0078 ///           unsigned integer type
0079 /// @tparam Bits A variable number of bits (numbers) that should be checked
0080 ///
0081 /// @param bitfield The bitfield that should be checked
0082 /// @param bits     The bits that should be checked
0083 ///
0084 /// @returns true if any of the passed bits is set in the bitfield and false
0085 ///          otherwise
0086 template <typename T, typename... Bits>
0087 constexpr bool checkAnyBits(T bitfield, Bits... bits) {
0088   static_assert((std::is_same_v<Bits, int> && ...), "All bit numbers to set must be integers");
0089   static_assert(sizeof...(bits) > 0, "Need at least one bit to check");
0090   return (false || ... || checkBit(bitfield, bits));
0091 }
0092
0093 } // namespace edm4hep::utils
0094
0095 #endif // EDM4HEP_UTILS_BIT_UTILS_HH