diff options
Diffstat (limited to 'ipc/chromium/src/base/basictypes.h')
| -rw-r--r-- | ipc/chromium/src/base/basictypes.h | 262 |
1 files changed, 262 insertions, 0 deletions
diff --git a/ipc/chromium/src/base/basictypes.h b/ipc/chromium/src/base/basictypes.h new file mode 100644 index 0000000000..8cd84bee59 --- /dev/null +++ b/ipc/chromium/src/base/basictypes.h @@ -0,0 +1,262 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +// Copyright (c) 2006-2008 The Chromium Authors. All rights reserved. +// Use of this source code is governed by a BSD-style license that can be +// found in the LICENSE file. + +#ifndef BASE_BASICTYPES_H_ +#define BASE_BASICTYPES_H_ + +#include <limits.h> // So we can set the bounds of our types +#include <stddef.h> // For size_t +#include <string.h> // for memcpy + +#include "base/port.h" // Types that only need exist on certain systems + +#include "mozilla/Assertions.h" +#include "mozilla/IntegerPrintfMacros.h" + +// A type to represent a Unicode code-point value. As of Unicode 4.0, +// such values require up to 21 bits. +// (For type-checking on pointers, make this explicitly signed, +// and it should always be the signed version of whatever int32_t is.) +typedef signed int char32; + +const uint8_t kuint8max = ((uint8_t)0xFF); +const uint16_t kuint16max = ((uint16_t)0xFFFF); +const uint32_t kuint32max = ((uint32_t)0xFFFFFFFF); +const uint64_t kuint64max = ((uint64_t)GG_LONGLONG(0xFFFFFFFFFFFFFFFF)); +const int8_t kint8min = ((int8_t)0x80); +const int8_t kint8max = ((int8_t)0x7F); +const int16_t kint16min = ((int16_t)0x8000); +const int16_t kint16max = ((int16_t)0x7FFF); +const int32_t kint32min = ((int32_t)0x80000000); +const int32_t kint32max = ((int32_t)0x7FFFFFFF); +const int64_t kint64min = ((int64_t)GG_LONGLONG(0x8000000000000000)); +const int64_t kint64max = ((int64_t)GG_LONGLONG(0x7FFFFFFFFFFFFFFF)); + +// Platform- and hardware-dependent printf specifiers +#if defined(OS_POSIX) +# define PRId64L "I64d" +# define PRIu64L "I64u" +# define PRIx64L "I64x" +#elif defined(OS_WIN) +# define PRId64L L"I64d" +# define PRIu64L L"I64u" +# define PRIx64L L"I64x" +#endif + +// A macro to disallow the copy constructor and operator= functions +// This should be used in the private: declarations for a class +#undef DISALLOW_COPY_AND_ASSIGN +#define DISALLOW_COPY_AND_ASSIGN(TypeName) \ + TypeName(const TypeName&); \ + void operator=(const TypeName&) + +// An older, deprecated, politically incorrect name for the above. +#undef DISALLOW_EVIL_CONSTRUCTORS +#define DISALLOW_EVIL_CONSTRUCTORS(TypeName) DISALLOW_COPY_AND_ASSIGN(TypeName) + +// A macro to disallow all the implicit constructors, namely the +// default constructor, copy constructor and operator= functions. +// +// This should be used in the private: declarations for a class +// that wants to prevent anyone from instantiating it. This is +// especially useful for classes containing only static methods. +#undef DISALLOW_IMPLICIT_CONSTRUCTORS +#define DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \ + TypeName(); \ + DISALLOW_COPY_AND_ASSIGN(TypeName) + +// The 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. If you use arraysize on +// a pointer by mistake, you will get a compile-time error. +// +// One caveat is that arraysize() doesn't accept any array of an +// anonymous type or a type defined inside a function. In these rare +// cases, you have to use the unsafe ARRAYSIZE_UNSAFE() macro below. This is +// due to a limitation in C++'s template system. The limitation might +// eventually be removed, but it hasn't happened yet. + +// This template function declaration is used in defining arraysize. +// Note that the function doesn't need an implementation, as we only +// use its type. +template <typename T, size_t N> +char (&ArraySizeHelper(T (&array)[N]))[N]; + +// That gcc wants both of these prototypes seems mysterious. VC, for +// its part, can't decide which to use (another mystery). Matching of +// template overloads: the final frontier. +#ifndef _MSC_VER +template <typename T, size_t N> +char (&ArraySizeHelper(const T (&array)[N]))[N]; +#endif + +#define arraysize(array) (sizeof(ArraySizeHelper(array))) + +// ARRAYSIZE_UNSAFE performs essentially the same calculation as arraysize, +// but can be used on anonymous types or types defined inside +// functions. It's less safe than arraysize as it accepts some +// (although not all) pointers. Therefore, you should use arraysize +// whenever possible. +// +// The expression ARRAYSIZE_UNSAFE(a) is a compile-time constant of type +// size_t. +// +// ARRAYSIZE_UNSAFE catches a few type errors. If you see a compiler error +// +// "warning: division by zero in ..." +// +// when using ARRAYSIZE_UNSAFE, you are (wrongfully) giving it a pointer. +// You should only use ARRAYSIZE_UNSAFE on statically allocated arrays. +// +// The following comments are on the implementation details, and can +// be ignored by the users. +// +// ARRAYSIZE_UNSAFE(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. + +#define ARRAYSIZE_UNSAFE(a) \ + ((sizeof(a) / sizeof(*(a))) / \ + static_cast<size_t>(!(sizeof(a) % sizeof(*(a))))) + +// Use implicit_cast as a safe version of static_cast or const_cast +// for upcasting in the type hierarchy (i.e. casting a pointer to Foo +// to a pointer to SuperclassOfFoo or casting a pointer to Foo to +// a const pointer to Foo). +// When you use implicit_cast, the compiler checks that the cast is safe. +// Such explicit implicit_casts are necessary in surprisingly many +// situations where C++ demands an exact type match instead of an +// argument type convertable to a target type. +// +// The From type can be inferred, so the preferred syntax for using +// implicit_cast is the same as for static_cast etc.: +// +// implicit_cast<ToType>(expr) +// +// implicit_cast would have been part of the C++ standard library, +// but the proposal was submitted too late. It will probably make +// its way into the language in the future. +template <typename To, typename From> +inline To implicit_cast(From const& f) { + return f; +} + +// The COMPILE_ASSERT macro (below) creates an otherwise-unused typedef. This +// triggers compiler warnings with gcc 4.8 and higher, so mark the typedef +// as permissibly-unused to disable the warnings. +#if defined(__GNUC__) +# define COMPILE_ASSERT_UNUSED_ATTRIBUTE __attribute__((unused)) +#else +# define COMPILE_ASSERT_UNUSED_ATTRIBUTE /* nothing */ +#endif + +// 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_UNSAFE(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. + +// Avoid multiple definitions for webrtc +#if !defined(COMPILE_ASSERT) +template <bool> +struct CompileAssert {}; + +# define COMPILE_ASSERT(expr, msg) \ + typedef CompileAssert<(bool(expr))> \ + msg[bool(expr) ? 1 : -1] COMPILE_ASSERT_UNUSED_ATTRIBUTE +#endif + +// 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. + +// MetatagId refers to metatag-id that we assign to +// each metatag <name, value> pair.. +typedef uint32_t MetatagId; + +// Argument type used in interfaces that can optionally take ownership +// of a passed in argument. If TAKE_OWNERSHIP is passed, the called +// object takes ownership of the argument. Otherwise it does not. +enum Ownership { DO_NOT_TAKE_OWNERSHIP, TAKE_OWNERSHIP }; + +// The following enum should be used only as a constructor argument to indicate +// that the variable has static storage class, and that the constructor should +// do nothing to its state. It indicates to the reader that it is legal to +// declare a static instance of the class, provided the constructor is given +// the base::LINKER_INITIALIZED argument. Normally, it is unsafe to declare a +// static variable that has a constructor or a destructor because invocation +// order is undefined. However, IF the type can be initialized by filling with +// zeroes (which the loader does for static variables), AND the destructor also +// does nothing to the storage, AND there are no virtual methods, then a +// constructor declared as +// explicit MyClass(base::LinkerInitialized x) {} +// and invoked as +// static MyClass my_variable_name(base::LINKER_INITIALIZED); +namespace base { +enum LinkerInitialized { LINKER_INITIALIZED }; +} // namespace base + +#endif // BASE_BASICTYPES_H_ |