| // Protocol Buffers - Google's data interchange format |
| // Copyright 2008 Google Inc. All rights reserved. |
| // https://developers.google.com/protocol-buffers/ |
| // |
| // Redistribution and use in source and binary forms, with or without |
| // modification, are permitted provided that the following conditions are |
| // met: |
| // |
| // * Redistributions of source code must retain the above copyright |
| // notice, this list of conditions and the following disclaimer. |
| // * Redistributions in binary form must reproduce the above |
| // copyright notice, this list of conditions and the following disclaimer |
| // in the documentation and/or other materials provided with the |
| // distribution. |
| // * Neither the name of Google Inc. nor the names of its |
| // contributors may be used to endorse or promote products derived from |
| // this software without specific prior written permission. |
| // |
| // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| |
| #ifndef GOOGLE_PROTOBUF_MACROS_H__ |
| #define GOOGLE_PROTOBUF_MACROS_H__ |
| |
| #include <google/protobuf/stubs/port.h> |
| |
| namespace google { |
| namespace protobuf { |
| |
| #undef GOOGLE_DISALLOW_EVIL_CONSTRUCTORS |
| #define GOOGLE_DISALLOW_EVIL_CONSTRUCTORS(TypeName) \ |
| TypeName(const TypeName&); \ |
| void operator=(const TypeName&) |
| |
| #undef GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS |
| #define GOOGLE_DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \ |
| TypeName(); \ |
| TypeName(const TypeName&); \ |
| void operator=(const TypeName&) |
| |
| // =================================================================== |
| // from google3/base/basictypes.h |
| |
| // The GOOGLE_ARRAYSIZE(arr) macro returns the # of elements in an array arr. |
| // The expression is a compile-time constant, and therefore can be |
| // used in defining new arrays, for example. |
| // |
| // GOOGLE_ARRAYSIZE catches a few type errors. If you see a compiler error |
| // |
| // "warning: division by zero in ..." |
| // |
| // when using GOOGLE_ARRAYSIZE, you are (wrongfully) giving it a pointer. |
| // You should only use GOOGLE_ARRAYSIZE on statically allocated arrays. |
| // |
| // The following comments are on the implementation details, and can |
| // be ignored by the users. |
| // |
| // ARRAYSIZE(arr) works by inspecting sizeof(arr) (the # of bytes in |
| // the array) and sizeof(*(arr)) (the # of bytes in one array |
| // element). If the former is divisible by the latter, perhaps arr is |
| // indeed an array, in which case the division result is the # of |
| // elements in the array. Otherwise, arr cannot possibly be an array, |
| // and we generate a compiler error to prevent the code from |
| // compiling. |
| // |
| // Since the size of bool is implementation-defined, we need to cast |
| // !(sizeof(a) & sizeof(*(a))) to size_t in order to ensure the final |
| // result has type size_t. |
| // |
| // This macro is not perfect as it wrongfully accepts certain |
| // pointers, namely where the pointer size is divisible by the pointee |
| // size. Since all our code has to go through a 32-bit compiler, |
| // where a pointer is 4 bytes, this means all pointers to a type whose |
| // size is 3 or greater than 4 will be (righteously) rejected. |
| // |
| // Kudos to Jorg Brown for this simple and elegant implementation. |
| |
| #undef GOOGLE_ARRAYSIZE |
| #define GOOGLE_ARRAYSIZE(a) \ |
| ((sizeof(a) / sizeof(*(a))) / \ |
| static_cast<size_t>(!(sizeof(a) % sizeof(*(a))))) |
| |
| // The COMPILE_ASSERT macro can be used to verify that a compile time |
| // expression is true. For example, you could use it to verify the |
| // size of a static array: |
| // |
| // COMPILE_ASSERT(ARRAYSIZE(content_type_names) == CONTENT_NUM_TYPES, |
| // content_type_names_incorrect_size); |
| // |
| // or to make sure a struct is smaller than a certain size: |
| // |
| // COMPILE_ASSERT(sizeof(foo) < 128, foo_too_large); |
| // |
| // The second argument to the macro is the name of the variable. If |
| // the expression is false, most compilers will issue a warning/error |
| // containing the name of the variable. |
| |
| namespace internal { |
| |
| template <bool> |
| struct CompileAssert { |
| }; |
| |
| } // namespace internal |
| |
| #undef GOOGLE_COMPILE_ASSERT |
| #if __cplusplus >= 201103L |
| #define GOOGLE_COMPILE_ASSERT(expr, msg) static_assert(expr, #msg) |
| #else |
| #define GOOGLE_COMPILE_ASSERT(expr, msg) \ |
| ::google::protobuf::internal::CompileAssert<(bool(expr))> \ |
| msg[bool(expr) ? 1 : -1]; \ |
| (void)msg |
| // Implementation details of COMPILE_ASSERT: |
| // |
| // - COMPILE_ASSERT works by defining an array type that has -1 |
| // elements (and thus is invalid) when the expression is false. |
| // |
| // - The simpler definition |
| // |
| // #define COMPILE_ASSERT(expr, msg) typedef char msg[(expr) ? 1 : -1] |
| // |
| // does not work, as gcc supports variable-length arrays whose sizes |
| // are determined at run-time (this is gcc's extension and not part |
| // of the C++ standard). As a result, gcc fails to reject the |
| // following code with the simple definition: |
| // |
| // int foo; |
| // COMPILE_ASSERT(foo, msg); // not supposed to compile as foo is |
| // // not a compile-time constant. |
| // |
| // - By using the type CompileAssert<(bool(expr))>, we ensures that |
| // expr is a compile-time constant. (Template arguments must be |
| // determined at compile-time.) |
| // |
| // - The outter parentheses in CompileAssert<(bool(expr))> are necessary |
| // to work around a bug in gcc 3.4.4 and 4.0.1. If we had written |
| // |
| // CompileAssert<bool(expr)> |
| // |
| // instead, these compilers will refuse to compile |
| // |
| // COMPILE_ASSERT(5 > 0, some_message); |
| // |
| // (They seem to think the ">" in "5 > 0" marks the end of the |
| // template argument list.) |
| // |
| // - The array size is (bool(expr) ? 1 : -1), instead of simply |
| // |
| // ((expr) ? 1 : -1). |
| // |
| // This is to avoid running into a bug in MS VC 7.1, which |
| // causes ((0.0) ? 1 : -1) to incorrectly evaluate to 1. |
| #endif // __cplusplus >= 201103L |
| |
| } // namespace protobuf |
| } // namespace google |
| |
| #endif // GOOGLE_PROTOBUF_MACROS_H__ |
