celeritas/phys/AtomicNumber.hh

0001 //------------------------------- -*- C++ -*- -------------------------------//
0002 // Copyright Celeritas contributors: see top-level COPYRIGHT file for details
0003 // SPDX-License-Identifier: (Apache-2.0 OR MIT)
0004 //---------------------------------------------------------------------------//
0005 //! \file celeritas/phys/AtomicNumber.hh
0006 //---------------------------------------------------------------------------//
0007 #pragma once
0008
0009 #include "corecel/Assert.hh"
0010
0011 namespace celeritas
0012 {
0013 //---------------------------------------------------------------------------//
0014 /*!
0015  * Type-safe atomic number identifier.
0016  *
0017  * Atomic numbers (Z and A) have constraints that integers do not (zero is not
0018  * an atomic number, dividing one atomic number by another is meaningless) so
0019  * this type improves the semantics and safety.
0020  *
0021  * Generally speaking, Z and A numbers are used during setup and when
0022  * evaluating expressions that use atomic charge. Z or A should not be used to
0023  * "index" data during runtime.
0024  *
0025  * Constructing with a nonpositive values gives the result in a `false` state
0026  * (\c get will throw a \c DebugError).
0027  */
0028 class AtomicNumber
0029 {
0030   public:
0031     //! Construct with an invalid/unassigned value of zero
0032     constexpr AtomicNumber() = default;
0033
0034     //! Construct with the Z value
0035     explicit CELER_CONSTEXPR_FUNCTION AtomicNumber(int z_or_a_value)
0036         : value_(z_or_a_value)
0037     {
0038     }
0039
0040     //! True if value is assigned/valid
0041     explicit CELER_CONSTEXPR_FUNCTION operator bool() const
0042     {
0043         return value_ > 0;
0044     }
0045
0046     //! Get the Z or A value
0047     CELER_CONSTEXPR_FUNCTION int unchecked_get() const { return value_; }
0048
0049     // Get the Z or A value
0050     inline CELER_FUNCTION int get() const;
0051
0052   private:
0053     int value_{0};
0054 };
0055
0056 //---------------------------------------------------------------------------//
0057 // INLINE DEFINITIONS
0058 //---------------------------------------------------------------------------//
0059 /*!
0060  * Get Z or A value.
0061  */
0062 inline CELER_FUNCTION int AtomicNumber::get() const
0063 {
0064     CELER_ENSURE(*this);
0065     return value_;
0066 }
0067
0068 //---------------------------------------------------------------------------//
0069 // COMPARATORS
0070 //---------------------------------------------------------------------------//
0071 #define CELER_DEFINE_ATOMICNUMBER_CMP(TOKEN)                       \
0072     CELER_CONSTEXPR_FUNCTION bool operator TOKEN(AtomicNumber lhs, \
0073                                                  AtomicNumber rhs) \
0074     {                                                              \
0075         return lhs.unchecked_get() TOKEN rhs.unchecked_get();      \
0076     }
0077
0078 CELER_DEFINE_ATOMICNUMBER_CMP(==)
0079 CELER_DEFINE_ATOMICNUMBER_CMP(!=)
0080 CELER_DEFINE_ATOMICNUMBER_CMP(<)
0081 CELER_DEFINE_ATOMICNUMBER_CMP(>)
0082 CELER_DEFINE_ATOMICNUMBER_CMP(<=)
0083 CELER_DEFINE_ATOMICNUMBER_CMP(>=)
0084
0085 #undef CELER_DEFINE_ATOMICNUMBER_CMP
0086
0087 //---------------------------------------------------------------------------//
0088 }  // namespace celeritas