1 /* 2 Copyright (c) 2010, 2021, Oracle and/or its affiliates. 3 All rights reserved. Use is subject to license terms. 4 5 This program is free software; you can redistribute it and/or modify 6 it under the terms of the GNU General Public License, version 2.0, 7 as published by the Free Software Foundation. 8 9 This program is also distributed with certain software (including 10 but not limited to OpenSSL) that is licensed under separate terms, 11 as designated in a particular file or component or in included license 12 documentation. The authors of MySQL hereby grant you an additional 13 permission to link the program and your derivative works with the 14 separately licensed software that they have included with MySQL. 15 16 This program is distributed in the hope that it will be useful, 17 but WITHOUT ANY WARRANTY; without even the implied warranty of 18 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 19 GNU General Public License, version 2.0, for more details. 20 21 You should have received a copy of the GNU General Public License 22 along with this program; if not, write to the Free Software 23 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA 24 */ 25 /* 26 * jtie_tconv_enum.hpp 27 */ 28 29 #ifndef jtie_tconv_enum_hpp 30 #define jtie_tconv_enum_hpp 31 32 #include <jni.h> 33 34 // --------------------------------------------------------------------------- 35 // Java value <-> C enum conversions 36 // --------------------------------------------------------------------------- 37 38 // currently, only Java int <-> C enum mappings are supported 39 40 /** 41 * A root type for enum value argument/result mappings. 42 * Unlike the root class definitions for object (array etc) mappings, 43 * this class does not derive from a JNI type. Therefore, a conversion 44 * constructor/operator is used to facilitate the static type conversion 45 * between the Java formal and actual type in this mapping. 46 * While this approach (conceptually) involves creating instances of this 47 * root class at runtime, which hold the the enum value, this should be 48 * detectable to the compiler as purely type-changing copy operations. 49 */ 50 struct _jtie_jint_Enum { 51 // the enum value (cannot be const to enable assignment) 52 jint value; 53 54 // conversion constructor _jtie_jint_Enum_jtie_jint_Enum55 _jtie_jint_Enum(jint v) : value(v) {} 56 57 // conversion operator operator jint_jtie_jint_Enum58 operator jint() { return value; } 59 }; 60 61 /** 62 * Defines the trait type aliases for the mapping of 63 * an integral Java type to a C++ enum type. 64 * 65 * The macro takes these arguments: 66 * C: A C++ enum type name. 67 * T: A name tag for this mapping. 68 * 69 * Naming convention: 70 * type alias: specifies a mapping: 71 * ttrait_<T>_i jint <-> C 72 * ttrait_<T>_c_iv jint <-> const C 73 */ 74 #define JTIE_DEFINE_JINT_ENUM_TYPE_MAPPING( C, T ) \ 75 typedef ttrait< jint, C, _jtie_jint_Enum \ 76 > ttrait_##T##_iv; \ 77 typedef ttrait< jint, C const, _jtie_jint_Enum \ 78 > ttrait_##T##_c_iv; 79 80 /** 81 * A helper class template that predicates the supported type conversions 82 * by presence of specialization. 83 */ 84 /* 85 template < typename J, typename C > 86 struct is_valid_enum_type_mapping; 87 */ 88 89 // XXX to document 90 #define JTIE_INSTANTIATE_JINT_ENUM_TYPE_MAPPING( C ) 91 // template struct is_valid_enum_type_mapping< jint, C >; 92 93 // --------------------------------------------------------------------------- 94 95 #endif // jtie_tconv_enum_hpp 96