diff --git a/include/rosa/support/atom.hpp b/include/rosa/support/atom.hpp index 9a02796..55d51c4 100644 --- a/include/rosa/support/atom.hpp +++ b/include/rosa/support/atom.hpp @@ -1,210 +1,211 @@ //===-- rosa/support/atom.hpp -----------------------------------*- C++ -*-===// // // The RoSA Framework // //===----------------------------------------------------------------------===// /// /// \file rosa/support/atom.hpp /// /// \author David Juhasz (david.juhasz@tuwien.ac.at) /// /// \date 2017-2019 /// /// \brief Facility for *atoms*, short strings statically encoded as integers. /// /// \note This implementation is based on the \c atom implementation of CAF. /// \todo Check license. /// /// *Atoms* can be used to turn short string literals into statically generated /// types. The literals may consist of at most \c 10 non-special characters, /// legal characters are \c _0-9A-Za-z and the whitespace character. Special /// characters are turned into whitespace, which may result in different string /// literals being encoded into the same integer value, if any of those contain /// at least one special character. /// /// \note The usage of special characters in the string literals used to create /// *atoms* cannot be checked by the compiler. /// /// Example: /// /// \code /// constexpr AtomValue NameValue = atom("name"); /// using NameAtom = AtomConstant; /// /// [](NameAtom){ std::cout << "Argument of type NameAtom"; }(NameAtom::Value) /// \endcode /// //===----------------------------------------------------------------------===// #ifndef ROSA_SUPPORT_ATOM_HPP #define ROSA_SUPPORT_ATOM_HPP #include "rosa/support/debug.hpp" #include +#include namespace rosa { /// Maximal length of valid atom strings. constexpr size_t MaxAtomLength = 10; /// Underlying integer type of atom values. using atom_t = uint64_t; /// Turn \c rosa::atom_t into a strongly typed enumeration. /// /// Values of \c rosa::atom_t casted to \c rosa::AtomValue may be used in a /// type-safe way. enum class AtomValue : atom_t {}; /// Anonymous namespace with implementational details, consider it private. namespace { // clang-format off /// Encodes ASCII characters to 6-bit encoding. constexpr unsigned char AtomEncodingTable[] = { /* ..0 ..1 ..2 ..3 ..4 ..5 ..6 ..7 ..8 ..9 ..A ..B ..C ..D ..E ..F */ /* 0.. */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 1.. */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 2.. */ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, /* 3.. */ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 0, 0, 0, 0, 0, /* 4.. */ 0, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, /* 5.. */ 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 0, 0, 0, 0, 37, /* 6.. */ 0, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, /* 7.. */ 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 0, 0, 0, 0, 0}; // clang-format on /// Decodes 6-bit characters to ASCII constexpr char AtomDecodingTable[] = " 0123456789" "ABCDEFGHIJKLMNOPQRSTUVWXYZ_" "abcdefghijklmnopqrstuvwxyz"; /// Encodes one character and updates the integer representation. /// /// \param Current an encoded value /// \param CharCode a character to add to \p Current /// /// \return \p Current updated with \p CharCode constexpr atom_t nextInterim(atom_t Current, size_t CharCode) { return (Current << 6) | AtomEncodingTable[(CharCode <= 0x7F) ? CharCode : 0]; } /// Encodes a C-string into an integer value to be used as \c rosa::AtomValue. /// /// \param CStr a string to encode /// \param Interim encoded value to add \p CStr to it /// /// \return \p Interim updated with \p CStr constexpr atom_t atomValue(const char *CStr, atom_t Interim = 0xF) { return (*CStr == '\0') ? Interim : atomValue(CStr + 1, nextInterim(Interim, static_cast(*CStr))); } } // End namespace /// Converts a \c std::string into a \c rosa::AtomValue. /// /// \param S \c std::string to convert /// /// \return \c rosa::AtomValue representing \p S AtomValue atom_from_string(const std::string &S); /// Converts a string-literal into a \c rosa::AtomValue. /// /// \tparam Size the length of \p Str /// /// \param Str the string-literal to convert /// /// \return \c rosa::AtomValue representating \p Str /// /// \pre \p Str is not too long:\code /// Size <= MaxAtomLength + 1 /// \endcode template constexpr AtomValue atom(char const (&Str)[Size]) { // Last character is the NULL terminator. STATIC_ASSERT(Size <= MaxAtomLength + 1, "Too many characters in atom definition"); return static_cast(atomValue(Str)); } /// Lifts a \c rosa::AtomValue to a compile-time constant. /// /// \tparam V \c rosa::AtomValue to lift template struct AtomConstant { /// Constructor has to do nothing. constexpr AtomConstant(void) {} /// Returns the wrapped value. /// /// \return \p V constexpr operator AtomValue(void) const { return V; } /// Returns the wrapped value as of type \c rosa::atom_t. /// /// \return \c rosa::atom_t value from \p V static constexpr atom_t value() { return static_cast(V); } /// An instance *of this constant* (*not* a \c rosa::AtomValue). static const AtomConstant Value; }; // Implementation of the static member field \c rosa::AtomConstant::Value. template const AtomConstant AtomConstant::Value = AtomConstant{}; } // End namespace rosa namespace std { /// Converts a \c rosa::AtomValue into \c std::string. /// /// \param What value to convert /// /// \return \c std::string encoded in \p What string to_string(const rosa::AtomValue &What); /// Dumps a \c rosa::AtomValue to a given \c std::ostream. /// /// \param [in,out] OS output stream to dump to /// \param A \c rosa::AtomValue to dump /// /// \return \p OS after dumping \p N to it inline ostream &operator<<(ostream &OS, const rosa::AtomValue &A) { OS << to_string(A); return OS; } /// Converts a \c rosa::AtomConstant into \c std::string. /// /// \tparam V \c rosa::AtomValue to convert /// /// \note The actual argument of type `const rosa::AtomConstant` is ignored /// because the \c rosa::AtomValue to convert is encoded in the type itself. /// /// \return the original string encoded in \p V template string to_string(const rosa::AtomConstant &) { return to_string(V); } /// Dumps a \c rosa::AtomConstant to a given \c std::ostream. /// /// \tparam V the \c rosa::AtomValue to dump /// /// \param [in,out] OS output stream to dump to /// \param A \c rosa::AtomConstant providing \p V /// /// \return \p OS after dumping \p V to it template inline ostream &operator<<(ostream &OS, const rosa::AtomConstant &A) { (void)A; // Shut compiler about unused parameter. OS << to_string(V); return OS; } } // End namespace std #endif // ROSA_SUPPORT_ATOM_HPP