id_string.h - エンジンの C API リファレンス

id_string.h
  1. #pragma once
  2. #include <stdio.h>
  3. #include <stdint.h>
  5. #include "platform.h"
  7. namespace stingray_plugin_foundation {
  9. #define ID32_FORMAT "#ID[%08x]"
  10. #define ID64_FORMAT "#ID[%016llx]"
  12. // An IdString64 is a 64-bit hash of a string value. It can be used
  13. // instead of strings to save memory and processing time.
  14. //
  15. // If you know that the keyspace is small and want to save memory
  16. // you can use an IdString32 instead of an IdString64. IdString32
  17. // uses the same hash function as IdString64, but just keeps the
  18. // first 32 bits of the hash so you can do a reverse lookup using
  19. // the same tables.
  20. class IdString64
  21. {
  22. public:
  23.     IdString64();
  24.     explicit IdString64(uint64_t id);
  25.     explicit IdString64(const char *s);
  26.     IdString64(const char *s, uint64_t id);
  27.     IdString64(unsigned len, const char *s);
  29.     // Returns the stored hash value.
  30.     uint64_t id() const {return _id;}
  32.     // True if this is the empty string.
  33.     bool empty() const {return _id == 0;}
  35.     // True if this is not the empty string.
  36.     bool nonempty() const {return _id != 0;}
  38.     bool operator==(const IdString64 &o) const {return _id == o._id;}
  39.     bool operator!=(const IdString64 &o) const {return _id != o._id;}
  40.     bool operator<(const IdString64 &o) const {return _id < o._id;}
  42.     // Converts the id to a string on the format #ID[xxxxxxxxxxxxxxxx].
  43.     // Returns a pointer to a static copy of the result. This will be
  44.     // overwritten by next call.
  45.     const char *to_string() const {return to_id_hex();}
  47.     // Converts the id to a string on the format #ID[xxxxxxxxxxxxxxxx].
  48.     // Returns a pointer to a static copy of the result. This will be
  49.     // overwritten by next call.
  50.     const char *to_id_hex() const;
  52.     static const int HEX_BUFFER_SIZE = 17;
  54.     // Writes a hexadecimal null terminated string to the memory pointed
  55.     // to by `s`. There must be 17 bytes of allocated memory where `s`
  56.     // is pointing.
  57.     void to_hex(char *s) const {sprintf(s, "%016llx", (unsigned long long)_id);}
  59. private:
  60.     uint64_t _id;
  61. };
  63. // A 32 bit hashed string value. If your keyspace is too big and you
  64. // get collisions with this hash, you should switch to an IdString64
  65. // instead.
  66. class IdString32
  67. {
  68. public:
  69.     IdString32();
  70.     explicit IdString32(unsigned id);
  71.     explicit IdString32(uint64_t id64);
  72.     explicit IdString32(const char *s);
  73.     IdString32(const char *s, unsigned id);
  74.     IdString32(unsigned len, const char *s);
  76.     template <class STREAM> void serialize(STREAM &s) {
  77.         s & _id;
  78.     }
  80.     // Returns the stored hash value.
  81.     unsigned id() const {return _id;}
  83.     // True if this is the empty string.
  84.     bool empty() const {return _id == 0;}
  86.     // True if this is not the empty string.
  87.     bool nonempty() const {return _id != 0;}
  89.     bool operator==(const IdString32 &o) const {return _id == o._id;}
  90.     bool operator!=(const IdString32 &o) const {return _id != o._id;}
  91.     bool operator<(const IdString32 &o) const {return _id < o._id;}
  93.     const char *to_string() const {return to_id_hex();}
  94.     const char *to_id_hex() const;
  95.     static const int HEX_BUFFER_SIZE = 9;
  96.     char *to_hex(char *s) const {sprintf(s, "%08x", _id); return s;}
  98. private:
  99.     unsigned _id;
  100. };
  102. struct idstring_hash {
  103.     unsigned operator()(const IdString64 &t) const {return (t.id() >> 32);}
  104.     unsigned operator()(const IdString32 &t) const {return t.id();}
  105. };
  107. }
  109. #include "id_string.inl"
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