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Diffstat (limited to 'chromium/third_party/webrtc/base/template_util.h')
-rw-r--r-- | chromium/third_party/webrtc/base/template_util.h | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/chromium/third_party/webrtc/base/template_util.h b/chromium/third_party/webrtc/base/template_util.h new file mode 100644 index 00000000000..f0bf39c5f9d --- /dev/null +++ b/chromium/third_party/webrtc/base/template_util.h @@ -0,0 +1,112 @@ +/* + * Copyright 2011 The WebRTC Project Authors. All rights reserved. + * + * Use of this source code is governed by a BSD-style license + * that can be found in the LICENSE file in the root of the source + * tree. An additional intellectual property rights grant can be found + * in the file PATENTS. All contributing project authors may + * be found in the AUTHORS file in the root of the source tree. + */ + +#ifndef WEBRTC_BASE_TEMPLATE_UTIL_H_ +#define WEBRTC_BASE_TEMPLATE_UTIL_H_ + +#include <stddef.h> // For size_t. + +namespace rtc { + +// template definitions from tr1 + +template<class T, T v> +struct integral_constant { + static const T value = v; + typedef T value_type; + typedef integral_constant<T, v> type; +}; + +template <class T, T v> const T integral_constant<T, v>::value; + +typedef integral_constant<bool, true> true_type; +typedef integral_constant<bool, false> false_type; + +template <class T> struct is_pointer : false_type {}; +template <class T> struct is_pointer<T*> : true_type {}; + +template <class T, class U> struct is_same : public false_type {}; +template <class T> struct is_same<T,T> : true_type {}; + +template<class> struct is_array : public false_type {}; +template<class T, size_t n> struct is_array<T[n]> : public true_type {}; +template<class T> struct is_array<T[]> : public true_type {}; + +template <class T> struct is_non_const_reference : false_type {}; +template <class T> struct is_non_const_reference<T&> : true_type {}; +template <class T> struct is_non_const_reference<const T&> : false_type {}; + +template <class T> struct is_void : false_type {}; +template <> struct is_void<void> : true_type {}; + +namespace internal { + +// Types YesType and NoType are guaranteed such that sizeof(YesType) < +// sizeof(NoType). +typedef char YesType; + +struct NoType { + YesType dummy[2]; +}; + +// This class is an implementation detail for is_convertible, and you +// don't need to know how it works to use is_convertible. For those +// who care: we declare two different functions, one whose argument is +// of type To and one with a variadic argument list. We give them +// return types of different size, so we can use sizeof to trick the +// compiler into telling us which function it would have chosen if we +// had called it with an argument of type From. See Alexandrescu's +// _Modern C++ Design_ for more details on this sort of trick. + +struct ConvertHelper { + template <typename To> + static YesType Test(To); + + template <typename To> + static NoType Test(...); + + template <typename From> + static From& Create(); +}; + +// Used to determine if a type is a struct/union/class. Inspired by Boost's +// is_class type_trait implementation. +struct IsClassHelper { + template <typename C> + static YesType Test(void(C::*)(void)); + + template <typename C> + static NoType Test(...); +}; + +} // namespace internal + +// Inherits from true_type if From is convertible to To, false_type otherwise. +// +// Note that if the type is convertible, this will be a true_type REGARDLESS +// of whether or not the conversion would emit a warning. +template <typename From, typename To> +struct is_convertible + : integral_constant<bool, + sizeof(internal::ConvertHelper::Test<To>( + internal::ConvertHelper::Create<From>())) == + sizeof(internal::YesType)> { +}; + +template <typename T> +struct is_class + : integral_constant<bool, + sizeof(internal::IsClassHelper::Test<T>(0)) == + sizeof(internal::YesType)> { +}; + +} // namespace rtc + +#endif // WEBRTC_BASE_TEMPLATE_UTIL_H_ |