hb-cplusplus.hh (6262B)
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 25 #ifndef HB_CPLUSPLUS_HH 26 #define HB_CPLUSPLUS_HH 27 28 #include "hb.h" 29 30 #ifdef __cplusplus 31 32 #include <functional> 33 #include <utility> 34 35 #if 0 36 #if !(__cplusplus >= 201103L) 37 #error "HarfBuzz C++ helpers require C++11" 38 #endif 39 #endif 40 41 namespace hb { 42 43 44 template <typename T> 45 struct vtable; 46 47 template <typename T> 48 struct shared_ptr 49 { 50 using element_type = T; 51 52 using v = vtable<T>; 53 54 explicit shared_ptr (T *p = nullptr) : p (p) {} 55 shared_ptr (const shared_ptr &o) : p (v::reference (o.p)) {} 56 shared_ptr (shared_ptr &&o) noexcept : p (o.p) { o.p = nullptr; } 57 shared_ptr& operator = (const shared_ptr &o) { if (p != o.p) { destroy (); p = o.p; reference (); } return *this; } 58 shared_ptr& operator = (shared_ptr &&o) noexcept { v::destroy (p); p = o.p; o.p = nullptr; return *this; } 59 ~shared_ptr () { v::destroy (p); p = nullptr; } 60 61 T* get() const { return p; } 62 63 void swap (shared_ptr &o) noexcept { std::swap (p, o.p); } 64 friend void swap (shared_ptr &a, shared_ptr &b) noexcept { std::swap (a.p, b.p); } 65 66 operator T * () const { return p; } 67 T& operator * () const { return *get (); } 68 T* operator -> () const { return get (); } 69 operator bool () const { return p; } 70 bool operator == (const shared_ptr &o) const { return p == o.p; } 71 bool operator != (const shared_ptr &o) const { return p != o.p; } 72 73 static T* get_empty() { return v::get_empty (); } 74 T* reference() { return v::reference (p); } 75 void destroy() { v::destroy (p); } 76 void set_user_data (hb_user_data_key_t *key, 77 void *value, 78 hb_destroy_func_t destroy, 79 hb_bool_t replace) { v::set_user_data (p, key, value, destroy, replace); } 80 void * get_user_data (hb_user_data_key_t *key) { return v::get_user_data (p, key); } 81 82 private: 83 T *p; 84 }; 85 86 template<typename T> struct is_shared_ptr : std::false_type {}; 87 template<typename T> struct is_shared_ptr<shared_ptr<T>> : std::true_type {}; 88 89 template <typename T> 90 struct unique_ptr 91 { 92 using element_type = T; 93 94 using v = vtable<T>; 95 96 explicit unique_ptr (T *p = nullptr) : p (p) {} 97 unique_ptr (const unique_ptr &o) = delete; 98 unique_ptr (unique_ptr &&o) noexcept : p (o.p) { o.p = nullptr; } 99 unique_ptr& operator = (const unique_ptr &o) = delete; 100 unique_ptr& operator = (unique_ptr &&o) noexcept { v::destroy (p); p = o.p; o.p = nullptr; return *this; } 101 ~unique_ptr () { v::destroy (p); p = nullptr; } 102 103 T* get() const { return p; } 104 T* release () { T* v = p; p = nullptr; return v; } 105 106 void swap (unique_ptr &o) noexcept { std::swap (p, o.p); } 107 friend void swap (unique_ptr &a, unique_ptr &b) noexcept { std::swap (a.p, b.p); } 108 109 operator T * () const { return p; } 110 T& operator * () const { return *get (); } 111 T* operator -> () const { return get (); } 112 operator bool () { return p; } 113 114 private: 115 T *p; 116 }; 117 118 template<typename T> struct is_unique_ptr : std::false_type {}; 119 template<typename T> struct is_unique_ptr<unique_ptr<T>> : std::true_type {}; 120 121 template <typename T, 122 T * (*_get_empty) (void), 123 T * (*_reference) (T *), 124 void (*_destroy) (T *), 125 hb_bool_t (*_set_user_data) (T *, 126 hb_user_data_key_t *, 127 void *, 128 hb_destroy_func_t, 129 hb_bool_t), 130 void * (*_get_user_data) (const T *, 131 hb_user_data_key_t *)> 132 struct vtable_t 133 { 134 static constexpr auto get_empty = _get_empty; 135 static constexpr auto reference = _reference; 136 static constexpr auto destroy = _destroy; 137 static constexpr auto set_user_data = _set_user_data; 138 static constexpr auto get_user_data = _get_user_data; 139 }; 140 141 #define HB_DEFINE_VTABLE(name) \ 142 template<> \ 143 struct vtable<hb_##name##_t> \ 144 : vtable_t<hb_##name##_t, \ 145 &hb_##name##_get_empty, \ 146 &hb_##name##_reference, \ 147 &hb_##name##_destroy, \ 148 &hb_##name##_set_user_data, \ 149 &hb_##name##_get_user_data> {} 150 151 HB_DEFINE_VTABLE (buffer); 152 HB_DEFINE_VTABLE (blob); 153 HB_DEFINE_VTABLE (face); 154 HB_DEFINE_VTABLE (font); 155 HB_DEFINE_VTABLE (font_funcs); 156 HB_DEFINE_VTABLE (map); 157 HB_DEFINE_VTABLE (set); 158 HB_DEFINE_VTABLE (shape_plan); 159 HB_DEFINE_VTABLE (unicode_funcs); 160 HB_DEFINE_VTABLE (draw_funcs); 161 HB_DEFINE_VTABLE (paint_funcs); 162 163 #undef HB_DEFINE_VTABLE 164 165 166 #ifdef HB_SUBSET_H 167 168 #define HB_DEFINE_VTABLE(name) \ 169 template<> \ 170 struct vtable<hb_##name##_t> \ 171 : vtable_t<hb_##name##_t, \ 172 nullptr, \ 173 &hb_##name##_reference, \ 174 &hb_##name##_destroy, \ 175 &hb_##name##_set_user_data, \ 176 &hb_##name##_get_user_data> {} 177 178 179 HB_DEFINE_VTABLE (subset_input); 180 HB_DEFINE_VTABLE (subset_plan); 181 182 #undef HB_DEFINE_VTABLE 183 184 #endif 185 186 187 } // namespace hb 188 189 /* Workaround for GCC < 7, see: 190 * https://gcc.gnu.org/bugzilla/show_bug.cgi?id=56480 191 * https://stackoverflow.com/a/25594741 */ 192 namespace std { 193 194 195 template<typename T> 196 struct hash<hb::shared_ptr<T>> 197 { 198 std::size_t operator()(const hb::shared_ptr<T>& v) const noexcept 199 { 200 std::size_t h = std::hash<decltype (v.get ())>{}(v.get ()); 201 return h; 202 } 203 }; 204 205 template<typename T> 206 struct hash<hb::unique_ptr<T>> 207 { 208 std::size_t operator()(const hb::unique_ptr<T>& v) const noexcept 209 { 210 std::size_t h = std::hash<decltype (v.get ())>{}(v.get ()); 211 return h; 212 } 213 }; 214 215 216 } // namespace std 217 218 #endif /* __cplusplus */ 219 220 #endif /* HB_CPLUSPLUS_HH */