hb-cplusplus.hh 6.0 KB

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  1. /*
  2. * Copyright © 2022 Behdad Esfahbod
  3. *
  4. * This is part of HarfBuzz, a text shaping library.
  5. *
  6. * Permission is hereby granted, without written agreement and without
  7. * license or royalty fees, to use, copy, modify, and distribute this
  8. * software and its documentation for any purpose, provided that the
  9. * above copyright notice and the following two paragraphs appear in
  10. * all copies of this software.
  11. *
  12. * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
  13. * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
  14. * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
  15. * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
  16. * DAMAGE.
  17. *
  18. * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
  19. * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
  20. * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
  21. * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
  22. * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
  23. */
  24. #ifndef HB_CPLUSPLUS_HH
  25. #define HB_CPLUSPLUS_HH
  26. #include "hb.h"
  27. HB_BEGIN_DECLS
  28. HB_END_DECLS
  29. #ifdef __cplusplus
  30. #include <functional>
  31. #include <utility>
  32. #if 0
  33. #if !(__cplusplus >= 201103L)
  34. #error "HarfBuzz C++ helpers require C++11"
  35. #endif
  36. #endif
  37. namespace hb {
  38. template <typename T>
  39. struct vtable;
  40. template <typename T>
  41. struct shared_ptr
  42. {
  43. using element_type = T;
  44. using v = vtable<T>;
  45. explicit shared_ptr (T *p = nullptr) : p (p) {}
  46. shared_ptr (const shared_ptr &o) : p (v::reference (o.p)) {}
  47. shared_ptr (shared_ptr &&o) : p (o.p) { o.p = nullptr; }
  48. shared_ptr& operator = (const shared_ptr &o) { if (p != o.p) { destroy (); p = o.p; reference (); } return *this; }
  49. shared_ptr& operator = (shared_ptr &&o) { v::destroy (p); p = o.p; o.p = nullptr; return *this; }
  50. ~shared_ptr () { v::destroy (p); p = nullptr; }
  51. T* get() const { return p; }
  52. void swap (shared_ptr &o) { std::swap (p, o.p); }
  53. friend void swap (shared_ptr &a, shared_ptr &b) { std::swap (a.p, b.p); }
  54. operator T * () const { return p; }
  55. T& operator * () const { return *get (); }
  56. T* operator -> () const { return get (); }
  57. operator bool () const { return p; }
  58. bool operator == (const shared_ptr &o) const { return p == o.p; }
  59. bool operator != (const shared_ptr &o) const { return p != o.p; }
  60. static T* get_empty() { return v::get_empty (); }
  61. T* reference() { return v::reference (p); }
  62. void destroy() { v::destroy (p); }
  63. void set_user_data (hb_user_data_key_t *key,
  64. void *value,
  65. hb_destroy_func_t destroy,
  66. hb_bool_t replace) { v::set_user_data (p, key, value, destroy, replace); }
  67. void * get_user_data (hb_user_data_key_t *key) { return v::get_user_data (p, key); }
  68. private:
  69. T *p;
  70. };
  71. template<typename T> struct is_shared_ptr : std::false_type {};
  72. template<typename T> struct is_shared_ptr<shared_ptr<T>> : std::true_type {};
  73. template <typename T>
  74. struct unique_ptr
  75. {
  76. using element_type = T;
  77. using v = vtable<T>;
  78. explicit unique_ptr (T *p = nullptr) : p (p) {}
  79. unique_ptr (const unique_ptr &o) = delete;
  80. unique_ptr (unique_ptr &&o) : p (o.p) { o.p = nullptr; }
  81. unique_ptr& operator = (const unique_ptr &o) = delete;
  82. unique_ptr& operator = (unique_ptr &&o) { v::destroy (p); p = o.p; o.p = nullptr; return *this; }
  83. ~unique_ptr () { v::destroy (p); p = nullptr; }
  84. T* get() const { return p; }
  85. T* release () { T* v = p; p = nullptr; return v; }
  86. void swap (unique_ptr &o) { std::swap (p, o.p); }
  87. friend void swap (unique_ptr &a, unique_ptr &b) { std::swap (a.p, b.p); }
  88. operator T * () const { return p; }
  89. T& operator * () const { return *get (); }
  90. T* operator -> () const { return get (); }
  91. operator bool () { return p; }
  92. private:
  93. T *p;
  94. };
  95. template<typename T> struct is_unique_ptr : std::false_type {};
  96. template<typename T> struct is_unique_ptr<unique_ptr<T>> : std::true_type {};
  97. template <typename T,
  98. T * (*_get_empty) (void),
  99. T * (*_reference) (T *),
  100. void (*_destroy) (T *),
  101. hb_bool_t (*_set_user_data) (T *,
  102. hb_user_data_key_t *,
  103. void *,
  104. hb_destroy_func_t,
  105. hb_bool_t),
  106. void * (*_get_user_data) (const T *,
  107. hb_user_data_key_t *)>
  108. struct vtable_t
  109. {
  110. static constexpr auto get_empty = _get_empty;
  111. static constexpr auto reference = _reference;
  112. static constexpr auto destroy = _destroy;
  113. static constexpr auto set_user_data = _set_user_data;
  114. static constexpr auto get_user_data = _get_user_data;
  115. };
  116. #define HB_DEFINE_VTABLE(name) \
  117. template<> \
  118. struct vtable<hb_##name##_t> \
  119. : vtable_t<hb_##name##_t, \
  120. &hb_##name##_get_empty, \
  121. &hb_##name##_reference, \
  122. &hb_##name##_destroy, \
  123. &hb_##name##_set_user_data, \
  124. &hb_##name##_get_user_data> {}
  125. HB_DEFINE_VTABLE (buffer);
  126. HB_DEFINE_VTABLE (blob);
  127. HB_DEFINE_VTABLE (face);
  128. HB_DEFINE_VTABLE (font);
  129. HB_DEFINE_VTABLE (font_funcs);
  130. HB_DEFINE_VTABLE (map);
  131. HB_DEFINE_VTABLE (set);
  132. HB_DEFINE_VTABLE (shape_plan);
  133. HB_DEFINE_VTABLE (unicode_funcs);
  134. #undef HB_DEFINE_VTABLE
  135. #ifdef HB_SUBSET_H
  136. #define HB_DEFINE_VTABLE(name) \
  137. template<> \
  138. struct vtable<hb_##name##_t> \
  139. : vtable_t<hb_##name##_t, \
  140. nullptr, \
  141. &hb_##name##_reference, \
  142. &hb_##name##_destroy, \
  143. &hb_##name##_set_user_data, \
  144. &hb_##name##_get_user_data> {}
  145. HB_DEFINE_VTABLE (subset_input);
  146. HB_DEFINE_VTABLE (subset_plan);
  147. #undef HB_DEFINE_VTABLE
  148. #endif
  149. } // namespace hb
  150. /* Workaround for GCC < 7, see:
  151. * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480
  152. * https://stackoverflow.com/a/25594741 */
  153. namespace std {
  154. template<typename T>
  155. struct hash<hb::shared_ptr<T>>
  156. {
  157. std::size_t operator()(const hb::shared_ptr<T>& v) const noexcept
  158. {
  159. std::size_t h = std::hash<decltype (v.get ())>{}(v.get ());
  160. return h;
  161. }
  162. };
  163. template<typename T>
  164. struct hash<hb::unique_ptr<T>>
  165. {
  166. std::size_t operator()(const hb::unique_ptr<T>& v) const noexcept
  167. {
  168. std::size_t h = std::hash<decltype (v.get ())>{}(v.get ());
  169. return h;
  170. }
  171. };
  172. } // namespace std
  173. #endif /* __cplusplus */
  174. #endif /* HB_CPLUSPLUS_HH */